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Can toothbrush bristles be printed?
Is it possible to print toothbrush bristles using a common FDM 3D printer? I am particularly interested in the width of bristles, closeness together of each bristle, and the flexibility of each particular bristle.

Hello @J. Roibal, I noticed your question has been up for a while now. Have any of the answers below been able to solve your question? If so, would you mind accepting the appropriate answer. If not, what is missing so that we may help you further? Also, if you have figured it out on your own, you can always answer and accept your own solution. Thank you.

Actually last year a group did use a normal FDM printer to 3d print hair, brushed, etc. See the press release from Carnegie Mellon University
https://www.engadget.com/2015/10/29/3d-printing-hair-is-as-easy-as-using-a-hot-glue-gun/
http://technabob.com/blog/wp-content/uploads/2015/11/3d_printed_hair_by_Gierad_Laput_Xiang_Chen_Chris_Harrison_1.jpg
That said as far as I know you will not have access to this process, and is probably under a mountain of patents and other innovation killers.
Now how to do this outside of fancy software.
For a FDM printer the smallest nozzle I ever got was 0.1mm, it jammed instantly. One could print rows at this precision.
Now we have to move to something more advanced, such as DLP. Not the materials you want, but closer to the size you want. a formlabs can print at 25 microns. Which as a hair is 17 microns, you are "close enough" .. but a resin would be brittle and break. They do have other materials such as flexibles, but I am not familiar with them enough.
Also just going to mention. Tiny slivers of plastic is more likely to cut you than comb you.

One additional note on the formLabs  (form1+) it can create features that are 25 microns but in my experience getting it to reliably print that is hit or miss, especially when they're printed extremely close together like on a bristle.

At this point, an FDM printer probably wouldn't produce good results if you intend on printing the same design as current toothbrushes.
Each strand is about 0.007" in diameter which is slightly larger than the typical minimum diameter that can possibly be extruded. This doesn't leave much room to provide a well enough surface between layers.
With features this small you might run into issues with resolution and accuracy of the machine. The resolution may determine how well the strands are printed separately. The accuracy may determine how well each layer print over each other. If your machines accuracy is about 0.0005", then expect your layers to have run-out of about 0.0005"-0.001" on a 0.007" size feature. I'm also not accounting for how well the machine is maintained/tuned, which could detriment both resolution and accuracy.
So, it's possible on an FDM, but not probable at this time.
To help your odds:

Slow your feed rate way down (maybe 30-40mm/s)
Watch over and under extrusion. It will be more evident on smaller features like this. It either will look like a big blob or pretty much nothing. You should have settings in your slicer to help compensate.
Clean your extruder and drive gear and tune the tension on filament in the extruder assembly.
Use quality filament! If the filament is out of round, then over/under extrusion will occur.
Be mindful of any health organization requirements on the type of materials you're allowed to use for something that goes in your mouth. The same logic goes for ensuring you don't print the bristles in something that can mold. I believe nylon is safe, at least in the US, but don't quote me on this.

Just to add to this, even FDA approved printed materials would not qualify for in the mouth. As ones printer will not meet FDA standards.

@StarWind do you happen to know how the printed part would not meet FDA standards? Not even for natural PLA or Nylon?

We had a long conversation about it in the facebook group I run, 3d printing hobbyists. The issue comes down to your machine is not going to meet food grade / clean room standards. The member who worked in that space was very sure about it. The plastic will.

I thought it was silly, given the temps we are talking about

That's right! There's the issue with contamination in the nozzle and build plate setups (tape, glue, etc.), right?

Theres a lot of points of failures for contamination. This discussion was primarily about the machine it self. Oil, blood from cuts, unwashed hands from employees. Then the enviorment it is in. A Chipolte grill is cleaned and  taken care of. Employees have hairnets and so on. A dirty workshop is another vector.

I have had a go at doing something for a christmass tree using a drop loop technique. You could use the same method or somthing similar to try and create something that looks like toothbrush bristles, but I don't think you would want to try cleaning your teeth with it.

Could you maybe add a bit more detail? What's a "droop loop" technique?

Basically, the printer prints a line out from the model in thin air and then back to the model creating a loop or string of filament.


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What is the biggest size of an object that iBox Nano can print?
Since iBox Nano is the smallest public-production-available 3d Resin printer (and the cheapest so far), I assume it has a huge size limitation. So far I've only seen pictures of its outputs that are miniature things. I've never tried it nor have I seen it in action in person so I'd like to be sure.
For example, my 3D models are of the size of beads to figurines to a standard sized pencil cup holder.
I want to know in inches or millimeters the dimension (width, length, height) of the biggest possible object the iBox Nano can print.

It's not likely that you can consider the iBox Nano as a public production available printer, as the majority of Kickstarter backers have never received a printer nor a refund. Use care if you are going to be sending money to someone promising this model of printer.

On their website, I found the following picture, which states a build area of 40 mm x 20 mm x 90 mm (1.57" x 0,79" x 3.54").

From their website I found a comparison between 300 microns down to 50 microns print quality. My answer would be somewhere around this range.

The question asks for maximum print size, not minimum feature size.

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CubePro 3D Printer
How to check leveling of printer bed ?
What should be ideal values on x,y and z to ensure printer bed is flat and there is no angle between plane of nozzle and plane of printer bed ?

The CubePro printer appears to have a comprehensive leveling system built into the menu. The direct instructions for this process can be found here:
CubePro Calibration
I would suggest that "ideal values" are those created by the calibration process that confirms the necessary settings for a good print.

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Differences between moving build plate vs. extruder
What are the differences, and pros & cons, between 3D printers with varying layouts for moving head vs. moving build plate?
Example layouts would include:

X Head; YZ Bed;
XY Head; Z Bed;
XYZ Head;
etc.

In particular, what are their respective strengths, weaknesses, specializations, maintenance considerations, etc.?

I believe this question falls into the "too vague" category. I believe this answer falls into the not-specific-enough-answer category.

I tried an answer underneath, because even though I agree that it is 'too vague', I think it is an answer that is of many people's concern in exactly that way when they begin. I would leave it as a portal to more specific questions which I would try to link in my answer.

The page http://reprap.org/wiki/Category:Mechanical_arrangement has links to "Cartesian-X-head", "Cartesian-XY-head", "Cartesian-XYZ-head", "Cartesian-XZ-head", "Cartesian-Z-head", etc. which give a list of (some) printers that use each arrangement.

I'm glad this question has stayed up, it provides a good overview on the topic.

Without going into too much detail, since this is a very exhaustive topic, I'll write some pro's of each down from the top of my head:
Cartesian XZ hotend, Y bed (eg. Prusa Mendel):

easy to build (relatively)
easy to maintain
easy to modify
understandable kinematics
with the right frame, no x-y-z orthogonality (90 degree angles) needs to be adjusted
affordable
bad for timelapse recordings
print quality will theoretically always be inferior at the same speeds and accelerations to kinematics that have less mass to move (heavy printbeds will lead to ghosting)
z-wobble is only existent in this approach
big build-plates are no option for this design (last feasible size might be 20x30 cm)

Cartesian XY hotend, Z bed (core-XY, sparkcube, Ultimaker, Makerbot)

less mass to be moved -> faster print speeds possible
almost no size limitaions
construction is easy to enclose in most models due to the cubic frame
looks almost always professional
enclosure can be hard to modify due to constraints in space

XYZ hotend (Delta bots)

master of circles
less mass to be moved -> faster print speeds possible
impressive to watch
more load on the processing unit due to more complicated kinematics (32 bit needed for fast print speeds and responsive control with display)
kinematics not easily understandable
error-cause search can be very complicated
more accurate in the center than on the outer limits due to the kinematic approach

The list is for sure not complete, and as a major disclaimer: print quality will always, with every approach, depend more on the setup and calibration of the printer than on the model. There are people around that produce great prints from an acrylic frame cartesian printer and lots of people that produce mediocre results with expensive printers in fancy designs.
I will add some links to the list items when I find the time, for now you have to believe me. I am highly appreciating corrections and additions!

I think this is simple, breaking it into simple parts... It is much easier to calibrate a machine where each axis does one thing. For instance, the Ultimaker; one of the few XY-on-the-same-axis printers... It has such a crazy complicated pulley system. If one thing gets out of whack, everything will start binding. Thankfully this doesn't happen as they did a good job, but it comes at a price. All the double pulleys and double rods - that costs money.
However if you break it into smaller bits then less will go wrong.
When I upgraded my MendelMax 1.5 to use a PBC linear solid slide for the X axis, it instantly solved all my issues with the rods binding (two rods into one big slide).
To quote my coworker,

It's like balancing a stool. Is it easier to balance a 4 legged stool or a 3?

Following from that, there is probably a good hour's worth of mechanical engineering information that can be said in regards to the linear motion itself. I would rather calibrate one axis at at time, and not worry about weird behavior caused by a XYZ head.


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Extruder is running backwards?
I have a (HIC) version of the Prusa i3. I have recently installed the E3D v6 hotend and titan extruder. After fixing some other issues, I noticed that there is no filament being extruded. In addition, the gear looked like it was going in the wrong direction. How can I fix this?

You can either flip the connector for the motor around (i.e. plug it in backwards) or (if you are using Marlin firmware) look for the following line in configuration.h:  (using the Arduino editor open the Marlin file For your 3D Printer,  one of the tabs is labelled "configuration.h" click on that tab to bring it to the front for editing.  use the Edit, Find and put E0 in the find box, click find.  When you find the line below
#define INVERT_E0_DIR false

change false to true (or vice-versa). Note that if you go for the connector-flipping route, make sure that you only do this when the printer is turned off.

Flipping the connector can be described more precise, if your connector allows it: You can flip two leads of one(!) coil, flip the whole assembly, exchange the two coil leads (without flipping them). Whatever is easiest for you.

Also, make sure everything is POWERED OFF before you start messing with stepper motor wires.

The setting it to true didn't work for me.

@AustinDarga You should probably turn that into a separate question. One simple thing you should at least test: what happens if you command the extruder to turn backwards? Does it reverse direction to turn "forwards"?

@AustinDarga After changing the setting, you need to Flash the firmware and do a full seeding of the settings again.

Reverse the plug for the motor on the board. Or do firmware. Doesn't matter. *** assuming you have ramps and a standard stepper..

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Why is my print getting messed up mid-print?
I am using Slic3r to generate the GCode for my Marlin-based printer. For some reason with increasing height my print starts to get messed up. On another part it starts to act like this when there are small parts. Is this related to my Slic3r settings, maybe to much filament being extruded or is this due to something else?
Any help is highly appreciated and I can provide more pictures of messed up parts or slic3r config if necessary.

Can you please upload another image, it's hard to see what might have happened. From the current picture, it looks like the part was set on fire lol

@tbm0115 Just added another picture of a different part. It's hard to make the camera focus on the messed up part. I am printing the same part again with less infill right now to make sure it's not an overextrusion.

I can help you out if you provide the printing and the model of our printer. I have my own 3D printing company with 2 years of experience.

To me, this looks like a combination of bad filament, high temperature and/or fast speeds.

Too high extrusion temperature will make difficult to let each layer cool enough before the next layer begins. This is why you see the poor results on the smaller areas of the print in your second photo.
If you're using bad filament (out of round, non-virgin, or poorly stored filament) you might see a series of over/under extrusion areas or smoke from moisture in the filament.
Slowing down your feed rates can be tricky if your extrusion temps are too high. By slowing down, you're allowing layers to cool down a little bit more and solidify. If your previous layers are still relatively molten, you'll notice that the new layer of filament will adhere to it and potentially drag the previous layers as the nozzle continues to move. You'll see the results of this in the top-arc layers with an uneven curvature.

The filament has a constant diameter, I measured using a caliper. I reduced the temperature and also reduced the infill for that part, which solved the problem.

For me, this looks like a cooling problem. Try to print this part 2-4 times in one print and get sure your fan is cooling all the time.
It is a known problem, if the layers get smaller, that they do not have time to cool down. So you're printing on a wobbling bunch of still soft layers, which result in what you showed on the photo.
In my opinion, this has nothing to do with the filamen.

This can happen if your filament is having to be pulled off the spool and slipping in the extruder. Check if slippage is happening at the extruder, perhaps see if results change by providing some hand powered help.  I have seen this with some glossy PLA I have used.

The filament is not on a spool anymore as I also figured out this could be a problem.


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HE3D Prusa Z-Axis Motor Error
I have an HE3D Prusa XI3 that I have assembled but the z axis motors aren't functioning properly, they will whine instead of turn. They will turn if I use Z babystepping or position changes but will not when doing a fast position changes or in normal use

You are probably driving the motors with insufficient current. Try increasing the motor current, by adjusting the potentiometer on the respective stepper driver. Turn it clockwise until your motors stop skipping steps.

I've been playing with that... The Z-axis motors are running in parallel in this model, I think the A4988 isn't strong enough to torque two Nema 17's in parallel, but all this is rather foreign to me.

I realize that the motors are wired in series, not parallel. Sorry for the confusion.


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Good methods to clean extruder gear (hobbed) from filament pieces?
I'm using a CraftBot original to print PLA, but some of the filament has become stuck in the teeth of the extruder gear on its way into the hot end.  I'm having issues with the gear becoming stuck and "clicking" instead of turning, and I suspect it is because of the clogged teeth.  I haven't changed materials in a long time.  I've cleared several print head clogs, but each time the gear gets back around to the one spot, it seems to get stuck again.
Are there any good ways to clean this gear?  I was thinking of putting it in a toaster oven and trying to melt the PLA off it, ideally without setting my house on fire in the process.  Anyone have better ideas?

If you hear a clicking sound, it might be as well not enough power that is delivered to the motor, so that it loses steps. You can increase the current limit given (most likely by your pololu compatible stepper drivers).

I mostly use a tooth brush for that kind of problem

My coworkers got to the gear before I did, and used a tooth brush and alcohol to clean it off.  We have a new print job running now, and it appears to be working so far.

If your gear skips at the same place each time I have found on my machine that the gear does not fit the motor shaft properly and has a larger gap between the gear and the idler roller.
Check to see if there is a thicker buildup on one side of the gear than the other.
On my machine what I had to do was to use a spare motor cable and watch the gear as it turned, and at one point on the gear it would slip and shave off a small amount of filament.
If that turns out to be your problem use a good caliper to measure your motor shaft, and the inner diameter of the gear.
Sometimes the minimum shaft diameter and the maximum bore diameter of the gear are just enough to allow that small variance in the outer rotation diameter of the gear.
Sometimes just replacing the gear will solve the problem, and sometimes it will require a new motor and/or gear.
As an alternative you can clean the gear using Acetone and a toothbrush, but that will be required often and you will have buildup in the chamber below the gear which can also cause feed problems, and you must make sure that all Acetone has dried before using the extruder again.
I suggest starting with changing gears since they are the cheapest and using the Caliper to find the closet fit possible.
You can get gears on e-bay at very reasonable prices. and I bought several to get the best fit possible.
Good luck and consider if you want to make a more permanent repair or temporary repair when making your choice. I chose the more permanent one because the slippage was affecting some of my prints.

If you are able to remove the gear, as I suspect you can, a useful tool is the file card. It resembles a flat hair brush but the bristles are short wire, very stiff. In traditional use, it removes metal shavings from conventional metal files. It will easily remove plastic from between the gear teeth. If you are unable to remove the gear, but can access a portion of the exposed teeth, a suitably named dental pick can remove slowly the clogged material.
Cooking the gear may not cause a fire, but could carbonize the plastic onto the teeth, perhaps creating a greater problem.

I've also used the small brush for my razor. Just about the perfect size.

I got the impression, although normally I don't do impressions, that the OP was having difficulty removing the plastic. If it's simple powdering getting stuck in the teeth, your razor brush is a good idea. They are also stiff and reasonably short bristled. It's less likely the OP will set the house afire using a razor cleaning brush.

Thanks.  The plastic feels fairly well stuck in the gear teeth, but I'm going to acquire a file card brush and give that a try.  I'll let you know if it works.

I use an air bulb to clean dust out of teeth, but the clicking sounds like the stepper has too much mechanical load so i am guessing there is something solid stuck at that point. Poke it off with something sharp.

Yep, it's not dust, it's hardened bits of PLA that seem fused to the gear teeth.  The teeth are meant to dig into the incoming filament a bit, but they can't when they're full of old plastic, so the incoming filament can't move past the gear, and the stepper motor strains.


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What are some cheaper versions of Multi Jet 3D printing?
I noticed 3Dsystems has Multi Jet 3D printing where wax is used provide support and give users with high resolution 3D printed objects. I was wondering if there were cheaper and smaller Multi Jet 3D printing?
Can Form 1+ from FormLabs be considered to do the same job with resin?

Objet by Stratasys is a comparable technology (they call it PolyJet). SolidScape is also somewhat comparable (they also use jetting).
The FormLabs printers are not comparable. They use a completely different process, which can only print in one material. With jetting, you can mix different materials in the same part.


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How to create tappered thread in OpenSCAD?
Is there any simple way of creating tappered thread in OpenSCAD? I need something like 10 mm in diameter at the end, 9 at the top and the height of 10 mm.

Could you elaborate on what approach you took, what you've already tried and why it failed? That might help possible asnswers to know where to start explaining.

There's plenty of libraries for OpenSCAD for creating threads. Just couldn't find any for tapered thread (i.e. pipe thread).

I have contacted Dan Kirshner (the author of openscad threads library) and he has updated the library. Now it supports tapered threads. Thanks, Dan!
Thread-drawing modules for OpenSCAD

If your math and OpenSCAD skills are superior to mine, you may be able to make use of the OpenSCAD Metric Nut, Bolt & Threads Library located here:
OpenSCAD Metric Nut, Bolt & Threads Library
It uses various means to generate polygons about a radius and includes the formulae for partial revolutions. It is presumed in the design that the center of rotation for the generated polygons is constant. I looked over the code for outside thread and could easily determine the radius references.
With proper coding, you could generate a variable radius based on the height of the cylinder at a specific point and achieve the tapered effect you require.
I expect that you'd have to reduce your desired radius by a fraction, say 0.05 mm in order to embed the thread forming polygons within your tapered cylinder.
If you aren't a strong coder, disregard this answer.

So, no ready solution. Thanks for the comment. Will play with the library.


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How much work would be converting Prusa firmware/software for CNC use?
I have an option to purchase a hobby multi-purpose device (lathe/mill/drill/grinder/cutter) which is manually controlled, but easily converted for driving by stepper motors (all 3 axis are controlled by turning knobs that can be replaced by gears, with convenient mount to couple each to a stepper motor). I have the right motors and can easily obtain drivers for them.

That is the way to overcome the worst problem of converting Prusa to CNC: the flimsy mechanics not able to withstand stress and vibrations of machining. Then I can connect the drivers to the 3 axis of Prusa's electronics, optionally connect some driver of the spindle to the extruder output (or just control it manually), and it seems the hardware side of the device is done.
The problem is the rest - adapting the software. RepRap family of 3D printers being open source means their software and hardware can be adapted. It's only a matter of how hard it is.
Does anyone have any experience in that direction? What would such conversion involve? Just recalibration to the new gear/leadscrew ratios, or something more involved, like editing the sources to get rid of all the temperature safeguards and the likes?

Can you clarify specifically what you mean by "Prusa's electronics"? Many different control boards are used by Prusa i3 type printers.

@RyanCarlyle: I wasn't aware of that. Maybe instead of me clarifying, could the answer provide a short overview or make a suggestion of which board would be most suitable for the task?

Well, the really short answer to that specifically is that 3d printer electronics are designed for 3d printers, and don't necessarily have the right inputs/outputs, command options, or motion control style for CNC machines. You can certainly do it -- lots of people build crappy little mills that run on Marlin (the most widely used 3D printer firmware) -- but I wouldn't recommend it. Likewise, CNC controllers generally aren't good at 3D printing. The best "all-in-one" controller option is probably MachineKit, but it has a very steep learning curve and I would not recommend it for newbies.

So there are a few possible questions I think you might ask. "How do I convert this multi-purpose fabricating device into a 3D printer?" or perhaps something more specific like "How do I use a 3D printer controller like Marlin/RAMPS to do CNC milling?"  Or "How do I pick a controller for a multi-purpose fabricating device?"  But I have to add that this is a 3D printing Q&A community, and we don't really focus on all-in-one machines or CNC milling.

@Ryan: That's why instead of these, I'm asking a top-level one that skims the surface of these. One that will help me compile a checklist of things that I'll need to learn, the right questions to ask and the right places to ask them. I definitely don't expect a complete working solution in the current answer - just an overview of the problems I'm going to face.

Do your 'turning knobs that can be replaced by gears' set speeds or positions?

@kamuro: positions. The original, beyond the one lathe/drill/bit motor is fully manual, unmotorized. The knobs turn leadscrews that move the table (x,y) and the head (z) in mill mode, the blade (x,y,z) in lathe mode. It's a modular device which you can assemble in various configurations; three rail/leadscrew/knob assembly modules, a motor module with replaceable heads (radial vise, drill/bit head, grinder disc), a worktable with attachable vise, the "unmotorized side" lathe axis module, plus some "dumb structural" modules. You assemble them in any configuration, building the machine you need.

None, if I choose the right control board.
The Smoothieboard supports CNC "out of the box"; it requires initial configuration, which, while somewhat different, is actually easier than for a 3D printer. Boards supporting Grbl or Teacup will be compatible for XYZ too, but may require some tinkering if you want to control the spindle.
You can use the same CAD software, but the set of CAM tools will need to be considerably different.

Disclaimer
Questions about other machines is still in kind of a grey area right now 06/2016 and your question is, in my opinion, a bit too broad. However, I think it's a great topic to perhaps help direct the scope of this community.
The lowdown

3D printers, CNC Mills, CNC Lathes, CNC Routers, and Lasers are all very different! There are certainly areas where each of these may overlap, but the methodology is very different overall.
Software is not always interchangeable across machines (even within the same machine type) due to hardware requirements/communication.
Hardware is not always interchangeable across machines (even within the same machine type) due to design/scope of the purpose of the machine.

Things to consider
(In a nut-shell)
3D Printers
Hardware

Minimal speed/torque requirements compared to subtractive machine tools.
Good designs focus on temperature control via enclosures and/or electronics.
(Typically) uses heat block/nozzle/stepper motor to control material size/flow.

Software

Emphasis on "plug-n-play" UI/UX
Conceptually easier to generate tool paths. STL's provide outlines and software fills in the blanks like a coloring book.
Focus is on understanding material properties and temperature variability.

Common Variability

Material quality/shape
Environment temperature

CNC Mills/Routers/Lathes
Hardware

Maximum speed/torque requirements.
Good designs focus on rigid designs and handling harmonics.
Tighter tolerance components to ensure mechanical repeatability.
Relies on cutting tool size/shape to control material size/flow.

Software

Requires more manual input (typically) to account for where its tool is located. The mathematics heavily depend on accurate dimensions for the cutting tools, otherwise you could damage your part or the machine.
Good software allows many different "canned" tool paths for efficiency, tool types, and achieving desired surface finish.
Focus is on variability in cutting tool and speeds/feeds (as recommended by cutting tool suppliers for materials)

Common Variability

Material shape/hardness
Cutting tool shape/hardness
Cutting tool path

Lasers
Hardware

Minimal speed/torque requirements.
Good designs focus on consistent beam quality and spot focus, which is relative to constant power.
Uses focusing lens (sets spot size) to control material size.

Software

Emphasis on "plug-n-play" UI/UX and interoperability.
Dimensions are easier to achieve as less variability in the process compared to 3D printing/machining.
Focus is on laser power (typically for material type and depth).

Common Variability

Laser type
Spot size
Power supply

Summary
Overall there are many, very different variables to consider between these technologies. I only focused on variables you might see out of a hobbyist-style machine and if you've operated any of these you'll know that there are many more variables that pop up for any of these machines.
So, do not expect such a plug-n-play solution as each machine requires quality construction of its hardware, the ability to handle the variability of the process in its software, and, above all, an operator that understands the correlation and balance of these components.
All of that being said, there are some machines that seem to be tailored to this such as the machine by Diyouware and ZMorph (No affiliation, just examples). However, notice that they have created their own software to meet a lot of these communication requirements.
Update
I forgot to mention the fact that a kink in creating a interchangeable machine is the control interface. The controller converts the "software speak" into an easily parsed series of functions (typically G-Code) for the small computer to process its predetermined hardware processes. Ie, The slicer or CAM software determines that a layer of a circle be 3D printed, milled, routered, or lasered, so the controller should G02I2 which could parse to (For all intents and purposes in javascript, not a practical language) CWCircularInterpolation(2,null,null,null,null,null) and run as:
function CWCircularInterpolation(i,j,k,x,y,z){
 //Some code to take current position and command to create a canned circle path
}

The point is that the software needs to handle the conditions and constraints of a different machining process and provide a well-equipped machine with the right commands. There are a lot of different things to consider in attempting to combine these machining techniques into a single machine and get quality results.

I've worked with CNC professionally for a time, though only observed 3D printing from sidelines. I think I have the CAD/CAM software side covered - produce G-code that accounts for tool geometry, depth variance (layering), and so on. The hardware side would be covered too, to a degree. A rigid frame, good steppers, a drive with little play.

The problem is "the middle" - a driver (both electronics and firmware/software) that can interpret the G-code, respect the speeds encoded (and possibly allow on-the-fly adjustments), and drive the 3 motors (or 4, incl. spindle), allow easy calibration (each time the tool is replaced, new "origin" must be established), and pause/abort (and optionally allow "rewind" a couple steps back) in case the tool breaks and needs to be replaced/re-sharpened.

Why did you answer a question that is, in my opinion, too broad, with an answer that is even more broad? The question seems to be "what do I need to do to adapt the firmware to CNC machines" but your answer seems to focus on hardware.

Also, every decent CAM program meant to handle CNC milling will handle generation of the right G-code. The question is how robust is the Prusa's controller in interpreting the G-code. Obviously it won't be too happy if it's told to M04 S3500 as it can't get the extruder to spin at 3500RPM counter-clockwise. But how would it handle this? Ignore? Abort? Crash? If it ignores unknown codes, I'm happy with it. Otherwise my work would involve finding/writing a sanitizer/simplifier for g-code, to make it comprise pretty much of only G00, G01 and possibly G50.

@TomvanderZanden: If the first sentences would be 'Your goal is in my humble opinion way too broad and unfocused because the respective focuus of the machines you are trying to unify are too different. I will elaborate on this by highlighting the differences in methodology of each machine:', would that be better? I think this broad answer gives an excellent idea of what is needed to adapt 3D printer firmware to CNC machines, because it shows how flexible firm- and hardware need to be to be utilized for a hybrid machine.

@kamuro thank you, you got it! I recognize that the question is too broad, but it's also a grey area for this community. So, I wanted to encourage the questions at least,by answering this one. I figured there would be a meta post about it soon. I'll add a better preface to my post.

I haven't done this myself. But the temperature safeguards only apply to the 4th, the E axis for the filament. So configuring the right steps per mm would get you started.
The question is more what do you want to do with it and where do you get the G-Code to do that. You can not use a slicer to generate the G-Code for you.
But there is software for PCB Milling out there that should work with the configured Firmware.

I know any professional CAM software can produce G-code. I don't know about amateur/free options, but that's not a question for your site :) And as for slicing... once you reverse the Z axis and put restrictions on travel between work points, that becomes pretty analogous.


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Tinkerine 3D Printer
I am trying to print model for Prosthetic Hand
(File Here: http://www.thingiverse.com/thing:596966) using Tinkerine 3D Printer. It went smooth for first hour and after that it started messing up(attached image).
I checked the leveling of plate and it was fine. Also, the nozzle didn't get clogged anywhere. Can anyone suggest, what could be the reason for this or what should be inspected in order to overcome this?
Expected Result

Actual Result

Your question is very vague. In what way did it mess up? What printer are you using, and what model are you trying to print? What kind of settings did you slice it with?

I agree. Without knowledge about the way the printer fails there is no help. Consider taking some photos or  even making a video if it cannot be described in words.

Hello and welcome to 3D Printing SE! We've temporarily put a hold on your question in hopes that you might be able to review your question and provide more detail. Please update your question with more details so that we, as a community, can help you better.

Do you have a picture of the failed print?

Thanks for feedback.
I have updated the question, could you please check it once and let me if I sound clear about this issue now ?

Thanks for uploading the image! Since we do not know what the model is supposed to look like, could you explain what has gone wrong? Is there more than what looks obviously wrong (but might not be)? It would be great to explain what the printer's behavior was, - did it stop extruding, go to home positions, etc...

The issue occurring here is similar to a question asked over here. It looks as though this is a result of a hardware fault related to the stepper drivers. @DarthPixel recommended placing heatsinks on the stepper driver(s) and/or properly placed fans.

Depending on the design of your machine, some stepper drivers are going to be worked harder than others. For example, a MakerBot Replicator will work the X-Axis stepper driver more than the Z-Axis stepper driver. Therefore, you have a higher chance of overheating your X-Axis stepper driver.(Images are of A4988 Stepper Driver, not directly compatible with MakerBot Replicator)
Alternatively, I personally have seen the issue repeated by manually triggering one of the limit switches. The effects seemed to take effect on the next layer.

Thanks for your answer, its very helpful. Did your try placing heat sink on the stepper driver ? I just had a look on my machine and fans around the nozzle. I can see one of the fans wobbling, probably that could be the reason for not being able to provided constant damp for heat generated.

@AkankshaVishwakarma My Replicator doesn't accept the A4988 stepper drivers very easily. So, no, I didn't try placing a heat sink on my machine, but I have seen it help for other machines. The "wobbling" is a little concerning though. You should double check what temperatures you need to extrude your material. If you're extruding too high, missing insulation, etc. then your fans can burn up, leading to other serious print issues.


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Any fix for PLA prints getting more brittle over time?
I've been printing small quantities from a PLA filament spool on a Craftbot printer for about two months now.  Recently the printed objects have been coming out very brittle.  Some structures that printed fine two months ago are now difficult to re-print.  The print head gets clogged easily, and when the object does print, it's quite brittle and 1/4" to 1/8" rods will easily snap off if not handled gently.
I'll admit to not following the precautions for storage of PLA.  It's much easier to just leave the filament installed rather than trying to remove it after each print, so this one spool has just been sitting on the back of the printer for all these weeks now.  I'm sure it's been humid some of the days, we've had some rain here.
Has the spool of PLA been damaged just by leaving it exposed to room air for two months?  Could that be the sole cause of the brittle prints, or are there other possible causes?  Is there any way to fix the spool or future prints from this spool, or do I have to scrap it and get a new spool?

Have you tried drying the filament (eg in an oven on "warm")?

Haven't tried anything yet.  What temp is "warm"?  Less than 400F I would guess :)

Yeah, you don't want to overly soften the filament or it will go out of round and jam. Maybe 120F / 50C for a couple hours.

I had this as an answer, but the question was about PRINTS, not FILAMENT.
There is no question that PLA filament grows brittle with age. It grows so brittle that it will spontaneously break when subjected to stress.
I experience this as PLA breaking along the path between the spool and the printer when left untouched for a few hours. This happens even during the depth of a New England winter when the humidity is very low.
Part of this problem comes when the PLA is tightly coiled onto a spool with a small hub.  ...

The PLA seems to anneal the strain induced by winding so that when the filament is unwound the filament is again strained. The strain may open tiny cracks, which develop into larger cracks and breakage.
I have not had this problem with newer spools where the diameter of the hub is larger. Recently I threw out 4 spools that were 80% used because the remaining 20% broke several times during printing. I don't see this with open but less used rolls of filament I bought around the same time.
I do not have hard data on when I bought each spool.
Now, I avoid spools with small hubs.

Use an electric oven.  A gas oven generates combustion products that I think include water vapor.

Increase nozzle temperature. When the filament is new it will print easier, requiring less heat to print well. So if you didn't store your filament properly to begin with, increasing print temperature will make it jam less and increase layer bonding.
The reason for this is because the moisture that accumulates in the filament will absorb heat and evaporate when printed, meaning that the filament itself isn't getting the same amount of heating as it used to.
That being said, the storage suggestions mentioned by tbm should be your first priority. I personally put my filament in Zip Lock plastic bags and store these in a dry location not exposed to sun or temperature changes.

Awesome tip!  And yes I've been taking better care of my PLA these days, getting it off the printer and storing in a ZipLoc bag etc.  But cranking up the temp seems to help a lot.

Throw some silica gel moisture absorber packs into the ziplocs.

I save all of the little desiccant packages I get for exactly this reason!

PLA absorbs moisture, so keeping the filament dry is a key factor. Aside from that, PLA is naturally more brittle than other plastics like ABS and Nylon Sorry, tried to find a graph to prove it, but couldn't find one.
There's a good Google Group discussion and many other resources that go over good storage habits, but as for fixing the existing filament.
Try the following:

Place PLA in an enclosure (plastic bin, Zip-loc bag, etc.)
If you have some, add some moisture absorber(s)
Place the tub in a warm environment (naturally or artificially) and make sure the area is dry as possible (not in the shed in the back, by the woods...). Possibly next to a heater vent or space heater in your house?

Essentially, you're trying to treat the material. When the material goes through a heat treatment (aka the heat block in the extruder), the mechanical properties are beginning to change. The brittleness can be set by how quickly the material cools. I'm speculating that the moisture does any of the following:

Keeps the filament from heating up to the desired extrusion temperature.
Burns the filament.
The moisture is evaporated, leaving gaps in the extruded filament (under microscope).

I looked into this a few years ago and have forgotten most of what I found out, but I'll keep looking and update my answer here.

If you have some, add some moisture absorber(s) (desiccant packs).  If you don't have some, buy some and then add some moisture absorber(s).


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What should I pay attention to after taking a 3d printer from extended storage
So I have a self build Mendel Reprap style 3d printer.
I've not used it in sometime after moving house but I'm looking to use it again. What should I pay attention to before calibrating and running it again?

After storage you can check the following things before taking the machine into operation again:

Are all cables intact? You wouldn't want lose cables shorting your circuits, nor cables that may have become brittle or loose to break the circuitry during operation.
Wipe off dust of the axes. Depending on your design, this might not be a big issue. However, it does not take too much time and doesn't hurt. If you're using bushings, you don't want the dust shortening the lifetime of your rods/bushings if it is that easily avoidable. (side-note: the lifetime of bushings in regular 3D Printing use is more than you can print)
Apply fresh grease/oil, depending on what design your printer follows. The old grease/oil might have come off or aged.
Wipe off dust from the bed. - No dust on the nozzle, no dust embedded in your print.
While they most likely will not change, there is a chance that your thermistors are off. This property should be given by the manufacturer as max. drift/year.
Check your belts and pulleys. The belts might have come loose - tighten them again. If they lost their elasticity (does the 'curve' it made around the pulley stay to some extent?) they might need to be replaced.
Check your fans when turning on the printer. You wouldn't want to lose electronics when you can cover this with a look, however unlikely it might be.

Happy calibrating after that ;)
*edit:
As Tom already pointe out, most of these things are unlikely, due to the usually rigid construction of the printer. These are merely more or less likely possibilities of things that can go bad or worse in storage.
*/edit

I don't think thermistor drift is something that you need to worry about in 3D printing. Its effects are far too small to be noticed.

I agree, that's why I introduced it as 'while they most likely will not change' and used 'might'. Just wanted to take it into the list for covering all possibilities.

The main thing that might have changed is the bed level, so you should level the bed again. If your printer is sufficiently sturdy, this may not even be necessary (but this should become apparent during your first print). The remaining calibration parameters (steps per mm for all axes, PID tuning, etc...) should not have changed.
You should perhaps also check for any bolts/nuts/cables that might have come loose during transport. This is not particularly likely to have happened, unless something was loose to begin with.


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Can aged PLA be refurbished?
Inspired by another question and due to the fact that some of my filament will face the same problem when I will use them again, I wanted to know if there are proven recipies to get rid of water that has ben incorporated to PLA filament from humidity? One knows the filament had too much exposure to humidity when hearing tiny puffs during extrusion and/or more brittle prints.
I know about suggestions to heat the water out of the filament at a temperature well below the glass transition temperature, but can someone provide first hand knowledge or even evidence?

The easiest way to freshen up filament is hot air, although there are other options.
There is an optimal melt processing moisture level for every plastic, typically in the range of 0.1-0.2% water content by weight. But the equilibrium moisture content of most plastics in humid air can be more like 1%. As a consequence, hot air dehydration is standard practice to prepare plastic pellets for extrusion in industry. Pretty much every injection-molded and extruded plastic product in the world -- including 3d printer filament -- is made with pre-dried pellets. Hot air is blown through the pellets until they are below the moisture limit.
Different plastics tolerate extrusion with different amounts of moisture, and absorb different amounts of moisture. They can also tolerate different drying temperatures. So the ideal storage and drying conditions vary by material.

PLA absorbs relatively little moisture, but in humid environments can accumulate enough water content to cause steam bubbles during extrusion. In some cases, steam bubbles can contribute to hot end jamming. Extreme wetness has been known to cause swelling that can increase filament feed drag. It's arguable whether wetness actually causes brittleness, or if that is a separate aging issue. People who keep their homes below ~50% relative humidity usually don't have any problems. Leaving PLA in a dry environment for a week or two should adequately re-dry it, or it can be gently heated to about 120F / 50C for a couple hours. (Some people dry it hotter. but that risks deforming the filament.)
ABS also doesn't absorb very much water, but perhaps a little more than PLA. It also experiences steam bubbles, but that's typically the only issue. Homes below ~45% RH usually don't have problems. Storing ABS with fresh silica gel for a couple weeks will dry it. Or it can be oven-dried up to about 180F / 80C for an couple hours. HIPS can be treated the same.
The kind of PET used in plastic bottles is rapidly degraded into tar by hydrolysis when melted with any significant water content. So PETG filaments are specially blended to absorb less water and to be less damaged by water than PET. But there is still the possibility of bubbles and cloudy strands due to steam expansion at higher temperatures, and there is some evidence that wet PETG produces weaker, more brittle prints than dry PETG. Different manufacturers' blends require different conditions: some people report Taulman t-glase needs oven-drying and careful storage while Esun PETG is fairly tolerant of normal home humidity levels. Oven-drying at 150F / 65C should work well.
Nylon absorbs a huge amount of water, which causes it to swell considerably, produce massive steam bubbles, look cloudy, warp more, and adhere less than properly-dried nylon. It's nearly unprintable when wet. It should be oven-dried at around 150F / 65C for 4+ hours -- desiccant will not strip enough moisture from it. In fact, nylon will pull water out of used silica gel! Once dry, it should be stored with an aggressive desiccant (either bone-dry silica or preferably calcium chloride). It only takes a few hours of exposure to air for it to become excessively moist. Building a sealed drybox feed system is highly recommended to avoid exposed time during and between prints.
Polycarbonate is similar to nylon in that is is an aggressive water-absorber. It will look cloudy, produce steam bubbles, warp more, and provide very poor layer bonding when wet. It should be oven-dried at 180F / 80C if on a plastic spool (up to 250F / 120C if dried alone) for 4+ hours and then stored in a drybox with aggressive desiccant just like nylon. Note that some modern PC blends like Esun ePC are less prone to water absorption, at the cost of some decrease in mechanical properties.
PVA is basically destroyed by airborne humidity, since it literally dissolves in water. Store in a drybox with an aggressive desiccant at all times.

Composite filaments should be treated like the base material.
Some drying and prevention options:

Oven: The "warm" setting will usually work pretty well. Let the oven preheat and settle out for a while, and measure temperature with a good oven thermometer or thermocouple. Shield the filament from direct radiant heating and hot spots with aluminum foil, cookie sheets, etc. Electric ovens will dry faster than gas ovens, because burning natural gas produces some additional moisture. Do not leave the oven unattended if using temperatures above the glass point of the filament, or bad things may happen!
"Light bucket": A 5-gallon plastic bucket with an incandescent lightbulb inside is a pretty effective way to gently warm low-temp filament like PLA for drying or medium-term storage. Leave the lid slightly open if drying.
Food dehydrator: Works great. Set temperatures as per the oven temps above. The main challenge is getting a large enough space inside for a filament spool.
Desiccant: In order for desiccant to actively dry filament, it must be significantly more attractive to water than the filament is. And affinity for water is a function of how wet the material already is. That means dry desiccant can easily pull some water out of very wet filament, but wet desiccant can actually give water TO the filament! Rechargeable indicator desiccant (such as an Eva-Dry E-333 unit) is ideal. It's also important to have ENOUGH desiccant: silica gel can only absorb 10% of its weight in water at 20% RH. That means to pull 1% moisture content out of a wet 1kg spool, you would need to start with at least 100g of bone-dry, fresh-baked silica! "Used" silica is basically useless, it already contains too much water to pull any more from the filament. But you can re-dry the silica in an oven. 250F / 120C for 6 hours should be safe for all types of silica gel, but more aggressive drying (including microwave drying) is possible for some silica gels. Follow the gel manufacturer instructions.
Rice: Does not work. It's basically a myth that rice has drying power. A bag of rice you buy at the store is already pretty close to moisture equilibrium with the air, so it has minimal capacity to pull water from filament (or a soaked iPhone, for that matter). If you dry the rice in an oven to drive out its water first, it will work to some degree, but silica gel is considerably more effective.
Kitty litter: Silica gel style kitty litter is nearly identical to desiccant silica gel. Like rice, it is fairly close to saturated when you open the container, but can be dried in the oven to be a good cheap bulk desiccant. Clay type kitty litter is not as effective. Be careful of getting kitty litter dust all over your filament.
Dry storage A thick plastic box with an airtight seal is preferable. Look for recycling code 2 (HDPE) or 5 (PP) on the box. 5 gallon buckets with sealing lids also work fine. Ziplocks and other thin plastic bags are better than nothing, but are permeable to water (yes, really) and can only be relied on as long as there is fresh desiccant in the bag. Acrylic/plexiglas dryboxes have been sold by various people, but acrylic is very permeable to water, so I don't recommend that option.
Air conditioning: Simply keeping the air in your printing environment reasonably dry will protect PLA and ABS and other low-absorption filaments. It may help to buy a humidity monitor to get an understanding of your ambient humidity.

Now, considering the original question here, it's important to note that moisture content is not the only way filament can age or be damaged. PLA in particular is prone to becoming brittle over time. There are different theories for why this occurs. One is gradual chemical aging because poly(lactic acid) simply is not a very stable polymer. Moisture could contribute to that aging process, but true chemical aging would be irreversible even if the filament is later dried. How much this occurs should depend on the specific polymer blend and storage conditions.
Another theory for PLA aging is that the residual filament extrusion stresses (from being drawn down to the correct diameter and rapidly quenched in a water bath) are slowly creeping over time. Anyone who has placed a PLA part under heavy load for more than a few weeks will see PLA creep. It's a rather odd polymer in that it will "creep to failure" and crack at very low creep elongations rather than progressively deform in a ductile manner like most creep-prone materials. So if the PLA has significant stresses locked-in from the initial extrusion process (which is very common) it may be creeping into a more brittle arrangement of polymer molecules over time. That would explain the aging effect, and it would explain why "drying" sometimes rejuvenates the PLA: heating the filament near its glass point will allow the polymer molecules to gently relax and basically anneal to a less brittle state.

Thanks for the great overall information (which would have been another question of mine, too) and the specific infromation regarding the original question!

Storing PLAs in plastic zip locks along with Silica Gel helps with extraction of water from PLAs. If you don't have silica gel, grains of rice can be other work around for serving the purpose.

Be aware that zip-lock bags may not be perfectly air-tight or probably humidity-tight - but much better than nothing.
I have a food vacuum bagger, and have vacuum-sealed zipper type bags and placed them in the refrigerator, where they do not maintain their tight fit, i.e. air is seeping in.
I haven't done a study, but bags tagged for the freezer should be better, I know they are thicker.
"America's Test Kitchen" tried various bags, and liked the Ziploc brand double-zipper freezer bags.  To my amazement, a spool of filament "just" fits a gallon bag (YAY!).
If you can get true food-vacuum bags large enough for a spool for long-term storage, this is the best way.
I was pleased to learn what I SHOULD have known, namely that UV can be a factor -- and until right now had been storing my filament inside an east window that gets sun.

Calcium chloride is an excellent desiccant - often sold as a "closet dehumidifier", or in cold climates, as a very inexpensive by-the-bag ice melting "salt" (check the ingredients).
In absorbing moisture, the CaCl2 puddles, and is harmful such as to leather, so be sure you empty the liquid and refresh the crystals occasionally.
A US$7 humidity gauge may be purchased (Amazon, eBay, etc) and placed in a container with filament and desiccant to see how it is doing.
/Ward C, inventor of Xmodem & BBSs

Keep in mind gas ovens produce water when the gas is burned, so it isn't as effective as an electric oven for drying.
Silica desiccant is excellent for drying filament, but you will want at least some of the desiccant beads to be "indicating" type.  That is they show a color change when saturated with moisture.  Silica desiccant can be recharged in a 220 °F (104 °C) oven, and can withstand a higher temperature than the filament, and it expels water when warm even though a lot is present in a gas oven.  Indicating silica is typically blue or orange dry, pink or green when wet.  If you have white silica beads with just a small percentage of indicating beads in it, they will equalize in moisture so the indicating beads can be trusted to indicate for the whole batch.  Non-indicating silica is cheaper and can be spiked with a small dose of indicating beads.
I use an x-large (~5 gallon) double zipper ziploc "big bag" with my entire supply of filament inside, along with a cloth bag holding 2.5 pounds of indicating silica beads.  Even if the ziploc seal isn't perfect, the silica will maintain a low humidity until spent.  It is rated to reduce humidity to 40 % and hold 40 % by weight in water (not the 10 % mentioned above, past 40 % water and the humidity will rise past 40 %), but in my 46 % rh (relative humidity) house, my filament bag dropped to 15 % rh within 20 minutes (measured with a HVAC humidity meter).  The 2.5 pounds (1.1 kg) of silica can absorb 1 pound of water (0.45 kg).  You can weigh your silica to get an indication of how much water is in it.  I stored my filament in a vacuum chamber for a week while I waited for my order of desiccant to arrive, so the filament was quite dry before I filled the bag.  The vacuum chamber is not practical for storage as you have to evacuate it every time you open it, and it doesn't hold much.

I have turned unusable PLA into filament that printed well by putting it in a dry oven for a couple of hours.  I've used 90 degrees C (194 degrees F), which may be too hot as it distorts round filament to be flat sided as the filament softens and relieves stresses.  It printed well.  Perhaps 70 degrees C (158 degrees F) would less deform the filament.
Today I have a large plastic bin with rolls of filament and three color-changing rechargeable drying cartridges.  As soon as they look other than absolutely dry, I plug them in to recharge.  It may be insufficient for PETG and Nylon -- I don't yet have much experience.


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How does the sizes of nozzle diameter and the Z-axis layer resolution work?
I have a 3D Printer with 0.4 mm (400 micron) nozzle length and the printer guide suggests that it can print up to a layer thickness of 60 micron and has a accuracy up to 100 micron.
What I'm trying to understand is that, how does the 0.4 mm nozzle output a filament size lesser than it? How does that process work?  Does it reduce the speed at which the filament flows or something?

Yes, they do reduce the speed. Basically, the speed at which you feed filament determines how large of a volume comes out, and the distance you move the extruder means this volume gets distributed over this distance. However, this is not the whole story.
The size of your nozzle determines only two things: the maximum layer height and the minimum feature size. It does not affect minimum layer height (and obviously doesn't affect maximum feature size) although there are some practical constraints (you wouldn't want to print 0.1 mm layers with a 5 mm nozzle).
The nozzle squishes the filament down as it is extruded; the filament is basically forced into the gap between the nozzle and the previous layer. There's no limit to how thin of a layer you can print (the 60 micron figure is just something the marketing department made up, you can likely print even thinner layers). So long as you can position your Z-axis with sufficient accuracy (which is usually no problem) you can print arbitrarily thin layers.
On the other hand, the nozzle size does determine the maximum layer height. Your need the filament to be squished a bit, or else it won't stick to the previous layer properly. You can't print layers thicker than your nozzle size, and it is generally recommended to print with a layer size that is at most 80 % of your nozzle size (e.g. with a 0.4 mm nozzle you shouldn't attempt to print layers thicker than 0.32 mm) but this is just a guideline.
Your extrusion width is the width of the line deposited by your nozzle. This is generally (due to the mentioned squishing) a bit larger than your nozzle size. With a 0.4 mm nozzle you should set your extrusion width to something slightly larger, like 0.5 mm. It is technically possible to print with an extrusion width that is the same as (or even smaller) than your nozzle size, but this results in very weak prints: as mentioned before, you want the plastic to get squished slightly.
They claim an accuracy up to 100 micron. This doesn't mean that you can print features as small as 100 micron (since you can't, due to the extrusion width being much larger). What this means, is for example, that if you print a 10 mm cube, you should expect its real size to be between 9.9 mm and 10.1 mm. Such a cube does not have any features that are smaller than your minimum feature size, but its outer walls can be positioned with greater precision than this minimum feature size.
I should caution you that the 100 micron figure is "up to" and in practice you will have a hard time achieving this.

I knew about the accuracy part! Thank you for answering the the question really comprehensive. +1


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ABS Filament safety concerns
I have the XYZPrinting da-Vinci-1.0 with ABS filament. I am concerned about ventilation. If this is used inside, what safety precautions are necessary, which are recommended, and/or which are optional?

There have been many questions about safety before. This is quite likely to be a duplicate of one of them. Have you looked existing questions yet? They might contain the answer you're looking for.

You might be able to find the information here: http://3dprinting.stackexchange.com/questions/1292/should-i-enclose-my-3d-printer/1293 of http://3dprinting.stackexchange.com/questions/2/is-3d-printing-safe-for-your-health/12 and http://3dprinting.stackexchange.com/questions/49/are-there-any-methods-of-limiting-exposure-of-hazardous-fumes-and-odors-emitted

@kamuro This printer is enclosed. I did look through at 2/3 of those already. Also, I am not just concerned about when heating, but even when it is off. Or heated via ambient temperatures. Ventilation in general

Hi @MathFromScratch. I noticed there haven't been much activity to this question in a while. Did any of the links above answer it for you? And if not, how might we be able to fill the gap?

Yes... The issue with all 3d printing materials. Not just ABS, but worse with ABS is the fine air particulate and Ultra fine it creates during the 3d printing process. PLA is considered safer than ABS. But I fear people will use this as justification, it is like saying I only smoke one cig a day instead of two so I am safe and healthy. No it really should be taken seriously.
There are a number of scientific papers and articles proving that this is an issue. Specifically that 3d printers release ultra fine particles into the air. Which can damage the lungs over time. I would STRONGLY advise not using a 3d printer around children, or at least putting it in the garage where you will not contaminate your homes air supply.
I.E.

http://www.sciencedirect.com/science/article/pii/S1352231013005086
http://built-envi.com/portfolio/ultrafine-particle-emissions-from-3d-printers/
https://www.ncbi.nlm.nih.gov/pubmed/11139166
http://www.3ders.org/articles/20160201-new-study-shows-health-hazards-of-3d-printing-suggests-pla-could-be-your-safest-bet.html

Lot of these have some scary looking graphs. Note that I am being a bit sarcastic when I say "scary looking graphs" the take away is ABS has twice the Fine Partical emission as PLA. However should you be worried, is still up to debate. The idea is that FPE can maybe contribute to cancer or other illnesses. FPEs are thought to irritate the lungs.
These graphs are of the ultra fine particle emissions.

as you can see PLA is MUCH safer in this regard.
I cannot find the paper at the moment, but the recommendation is a full air cycle several times an hour. As someone that lives in a Cold state I personally just use PLA and am rolling the dice.
There is another SO where I cover my future plans for an air scrubber.
I will note that other materials such as Polycarbonate should just be plain avoided.
I also want to provide these links on WHY ultra fine particles are bad. In summary they really upset your lungs and are thought to cause lung cancer over time.
Wikipedia on Ultra fine particulates.
White paper on ultra fine particulates.

I am nearly offended at the "scary looking graphs" part. The graphs depict data, and that data has some interpretation. You can't tell whether something might be dangerous based on looking at graphs and saying "that looks scary!". You don't mention what the graphs depict (for the first graph, you haven't even listed the units of the vertical axis). According to the last graph, PLA emits 10 times fewer particles than ABS but I'm not sure how that justifies your "MUCH safer" claim. Perhaps the level of ABS is nothing to worry about to begin with, or even the level of PLA might pose a risk.

Fair point though try to not get offended by graphs haha. The issue is it's unknown exactly how dangerous but it is generally agreed that both pla and abs are dangerous. I think it's important to note that it's implied one should read the articles I posted along with the graphs  I'll also point out both graphs are of the same measurement. Ultra fine particles

“ABS has twice the Fine Partical emission as PLA” The graphs you posted are log scale. The second graph shows ABS having about 10x the UFP emission rate of PLA. In the first graph, the differences are in the 100x to 1000x range.

Most reputable suppliers of filament should have MSDS (Material Safety Data Sheet) available for the material they are providing. This sheet should provide you with some mechanical, electrical, and chemical properties as well as safety concerns. For the most part an ABS MSDS will tell you that it can be harmful to inhale or consume ABS in any phase state (solid, gas, liquid, etc.).
Although you didn't explicitly state it in your question, your ventilation tag will lead to some pretty good answers to a somewhat related question about air filtration options.

The second paragraph of this answer seems more suited as a comment.

I haven't printed much ABS but I rapidly realised that printing ABS in an enclosed space soon fills up with fumes, which apart from their toxic nature, see answer above, really stink. I close off the print space rest of the house and wear a two-filter painters respirator when in the same environment and ventilate the room when finished - I live in a temperate zone so leaving the window open isn't always an option and drafts can affect the print. Ideally, I should enclose the printer and filter the airflow but for the amount of ABS I print, it's not an economic option so a respirator it is.

your fine at practical temperatures.
source: https://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene#Hazard_for_humans
recommended would probably be set your controller to not go above 380c if your really worried. but it's not needed.

380C is WAY to hot for 3D printing. 230C is a more appropriate temperature. Also, the OP is requesting safety precautions related to the harmful fumes that ABS gives off during printing.

380 is too hot. 260 is probably far above what you would want but I wouldn't set a hardware limit at that.


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Can I use a metal filament on M3D Micro (or Pro)?
Can I use a metal filament such as Copper, Zinc Alloy, Silver filaments on M3D Micro? The Pro hasn't come out yet but I assume it would if the Micro can since the Pro is suppose to be the improvement edition.
An example of a metal filament that I found is this Silver PLA 1.75mm Filament. Here's one for Cooper PLA 1.75mm Filament.
I would like to make small sculptures or bracelet beads/charms, and whatever else I could think of making using metal. And, I'm asking because I'm new to 3d printing, I want to learn how to work with a 3d printer and M3D is very affordable for me. So I'm making sure before I buy. Note that I've emailed M3D twice and I didn't get any reply.
If not M3D, can any other 3D Printer comparable to M3D do this? The MBot Mini, maybe?

Most 3D printers that use non-proprietary filament can print exotic filaments, such as the ones you mention. One thing to be aware of, though, is that some of these filaments wear down the nozzle far more quickly than ordinary PLA, and therefore should be used with reinforced nozzles (unless you have extra nozzles to spare). Carbon fibre and metallic filaments are generally known to increase nozzle wear, while softer alloys such as wood and bamboo generally are less abrasive.
A quick google search reveals that many people have used non-proprietary filament on the M3D Micro successfully, but be aware that using such filaments is not covered by your warranty. If you are going to use abrasive filaments with your Micro, I would check that M3D allows you to replace the nozzle first.

It is my understanding that the metals are so fine and mixed in with other ingredients that you cannot tell that there is metal at all. But looks like its 100% metals.

I'm not sure that this really addresses the question of whether metal can be printed on the M3D, unless you meant to say "yes, because you can't tell there's metal so it prints like plastic" (in which case your answer wouldn't be entirely correct because of the issues raised by Tormod).

This answer might be okay if it was elaborated a bit more. My interpretation is that @Jeanie was hinting towards the idea that it is possible to technically print with "metal" filament without completely wearing down the extruder. If my interpretation is wrong, Jeanie, then please feel free to correct me and in the meantime, consider adding to your answer to avoid conversion to a comment.

I meant to say....yes you can use metal filament because it is blended into PLA at such a fine rate that you can't even tell it's in there except for the "look" as for wearing down the extruder...I don't know and I never mentioned the extruder. Nor was it mentioned in "the question"


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How can I program a 3D printer to move using Arduino?
I search about that topic, but all what I found, was the mechanical part of the 3d printer. But I didn't find, how to program it using arduino.
I want to make a cartesian 3d printer. I don't have a printer yet, but I will buy all the components that I need actually.
I know, how to control stepper motors, but I don't know, how I can program it in order to make the shape that I want.
This is my question: what I need to learn in order to let this 3d printer make this shapes?

It's really unclear what you need in terms of programming 3D printer using arduino. Do you have printer already? Are you gonna build or buy it? What kind of 3D printer you consider (cartesian / delta / scara)? Have you review the code of existing arduino 3D printer software? And the most important question - what do you want to programm? I hope you don't mind but I suspect that whole issue is too complicated if you cannot find any materials about programming 3D printed using ardiuno. I suggest reading about geometry and numeric methods and articles/tutorials about programming arduino.

Hi, and welcome to 3D printing SE! As @DarthPixel has stated below, answering your question can be very difficult because we do not understand specifically what your are asking about. Could you please let us why you are asking, what you have done/tried so far, and what specifically you want to know? I have put this question on hold until you have the time to make your edits.

I would be very happy to find interpunctuation in this question, now that it has been edited. And then, you might want to look up 3d printer firmware here http://reprap.org/wiki/List_of_Firmware . The most common firmwares might be Marlin and Repetier.

As @kamuro says, It sounds like what you are looking for is a firmware (unless you want to make it on your own)!

The question "how to design a 3D printer?" could be the subject of an entire book. It's far too broad for a stackexchange question. Engineering SE wouldn't accept "How to design an airplane?" as a question either.

@TomvanderZanden, although that is the title of the question, it seems that the actual question is about how to make a "printer move as a printer" (in Jeopardy, the question would be "What is Firmware". :)) I fully agree that the title needs to be changed, though!

Yes.
Look up Arduino Ramps 1.4
http://reprap.org/wiki/RAMPS_1.4
Following the programing is all done for you in the firmware. That said you can edit it. Just open the firmware files -- it is compiled when you upload them. Generally however one usually sticks to the preferences header alone..
http://reprap.org/wiki/List_of_Firmware
Over all you are trying to reinvent the wheel. When I started 5-6 years ago it was barely a thing. Now you buy a proven kit and get to the printing. That said if you are truly interested in designing check out.
https://www.facebook.com/groups/cncbuilddesign/
If you want help on picking a kit. Or what I really think you are looking for. A good place to start. This is one of the larger 3d printing groups. Full disclosure I run this one, but at 6k members I don't recruit.
https://www.facebook.com/groups/3DPrinterHobbyists/
I got my start in reprap IRC
http://reprap.org/wiki/IRC
Be aware there are trolls that now camp the IRC looking to sell you a printer. I would not engage with them, their printers are usually overpriced and sub par.
Best of luck.
Most of all I think you need to know it's Reprap all the way. Reprap forums, Reprap printers, Reprap kits, Reprap community. All the commercial printers started off the reprap project. Even if you buy a makerbot (don't) it's Reprap in it's roots.
https://vimeo.com/5202148

While Star Wind's answer is best as far as addressing what was not asked, but was probably the intent of the question, for educational purposes:
To control the printer you need an microcontroller (most popular are Arduino) which will interface with the motor drivers. Microcontrollers cannot output the current needed to control the motors, so motor drivers (such as this https://www.pololu.com/product/1182 ) are easy ways to control a stepper motor with higher current (and usually voltage). You can build your own if you are particularlly adventurous, they are essentially two H-bridge circuits.
The Arduino programming environment has a library for controlling stepper motors through a driver built in, you just tell it which pin to send the pulses to, and how fast, and a separate pin tells it to spin clockwise or counterclockwise.
For a 3D printer you need at least four motors working in unison, one for the X, Y, Z axis, and one for the extruder (E axis).
The existing programs that 3D printers use (Marlin, Sprinter, Teacup, etc) are all doing these simple steps at their core, but have implemented libraries of G-code that the printer uses to make control the stepper motors in unison to make the correct shape. Slicing programs such as Cura or Slic3r take in the 3D model and output the Gcode that the microcontroller is programmed to understand.

Hey Jex. I am sorry you did not understand their question. They asked how do I program an Arduino for a Cartesian 3d printer. They want to know how to make their printer work with an emphasis on Arduino. Your answer touches on Arduino but is clearly about microcontrollers in general. You also did not provide them with how to accomplish their goal which is 3d printing with a cartesian design. Please read the question more carefully as well as the other answers. See mine for an example on how to answer the specific question as well as the real intent behind the question.

authors: Александр Александрович


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Advance extrusion, extruder code help?
I not sure what this code does..... I recently bought a titan extruded that needs to be calibrated with my printer (417 microsteps http://wiki.e3d-online.com/wiki/Titan_Assembly#Firmware_Calibration).
I am having a hard time understanding why they have D_Filament at 2.85 (my printer was made using 1.85mm filament) and why they used it twice in there equation. Also, what are the arc interpretations for?
#ifdef ADVANCE
#define EXTRUDER_ADVANCE_K .0
#define D_FILAMENT 2.85
#define STEPS_MM_E 836
#define EXTRUTION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
#define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUTION_AREA)
#endif // ADVANCE

// Arc interpretation settings:
 #define MM_PER_ARC_SEGMENT 1

 #define N_ARC_CORRECTION 25

The extruder advance feature is probably not enabled on your printer, so this code effectively does nothing (and you don't need to mess with it). Extruder advance is a feature that tries to compensate for the delay between feeding (or retracting) the filament and the point at which it actually starts to extrude, but it's generally not used. The fact that the manufacturer left D_FILAMENT at the default of 2.85 probably means they didn't enable this. You can check whether it is enabled by seeing if there is an (uncommented) #define ADVANCE.
The reason D_FILAMENT appears twice is because they're computing the cross-sectional area of your filament, which proportional to the square of its diameter.
The arc interpolation settings have nothing to do with extruder calibration at all, but define the resolution at which G2/G3 approximate arcs. G2/G3 are currently not supported/used by most slicers, so you can safely ignore these settings since they don't do anything that would influence regular printing.
The only thing that you should change is the following line in the Configuration.h file:
#define DEFAULT_AXIS_STEPS_PER_UNIT   {80,80,4000,500}

Leave the first three values as-is (they may be different for your printer) and change the last one to 417.
You could also avoid changing the firmware at all, and use M92 E417 to set the steps per mm for your extruder, or (if you have an LCD) use the LCD to adjust the steps per mm.

Sailfish and MachineKit both have effective advance algorithms that everybody always uses with those firmwares. RepRapFirmware also has a working advance algorithm but I don't think many people are using it. Otherwise, Repetier, Marlin, Slic3r -- their advance implementations simply don't work, which is why they aren't used. It's just code bloat from failed experiments that didn't work. And Smoothie doesn't have any advance algorithm at all. So... there are perhaps 100,000 working 3d printers out there using pressure advance with good results, but not in the "mainstream" hobbyist community.


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How can I export a Materialise Magics Project as a STL file?
I created a new project in Materialise Magics, added a few parts (different STLs), moved them around in certain positions and now I want to export this project into another STL, containing my recent work.
The export menu seems to be all grey, like this function is not available. Do I have to do some repairing first or something similar? Or Magics needs other software in order to export a Magics Project to a STL file?

It's pretty common for software to prevent export of a failed model. From the little I've researched via YouTube videos, there is a wizard to help you find the failure points, some automatic repair and then perhaps manual repair required. I expect you'll find the export option returns when completed.

consider to also check each STL for validity (manifold) or need for repair.

I just finished doing that. I think the Support Generation module is not working or missing at all. I may need to find another software that supports adding multiple STL files in the same workspace, lets me do rotation and translation movements, edit coordinates and combine them in a single mesh to export the final model into a single STL instead of multiple. Do you know such of software? I have a student account at Autodesk and I'm now currently download Inventor.

I'm a big fan of blender and meshmixer, both free, but I can't say with certainty if either will do as you require. They are both more "organic" modeling programs while Inventor or SolidWorks and it's ilk are parametric and engineering oriented.

I found a workaround eventually. I moved each STL in the designated coordinates, exported them separately from Magic's "Save Part As" option and just imported them in 123D Design, because it keeps the original coordinates, and exported the design after in a single STL. Anyway, thanks :D

I gather from your post that you are trying to export a build file containing multiple individual pieces, possibly to be printed. I suggest using the 'Merge' tool to join each of the individual STL's into one file. You can then save it as as single part or export it to a printer. This information comes from my experience as an Additive manufacturing technician. The following link is a Github repo containing a workflow on this process:
Magic's Build File Creation

Instead of using save project as or export click save part as, this defaults to an STL file.


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First Layer problems?
I am using the E3D v6 hotend with the titan extruder. Everytime I go to do a test print, just enough stringy filament oozes comes out of the hotend "right before" it lays down the first layer. I have no idea why it oozes out the little bit of filament before it prints.... The unwanted filament builds up while some of the first layer is done. As a result, what has been printed or about to be printed get stuck together as it tries to do the rest of the print....

Hi, Chris! What filament and temperature are you printing at? FYI, this is common for bowden pinters: my bowden printer also oozes as the hotend heats up due to the hystiresis (or "spring effect") of the bowden tube. I do not know if the Titan extruder could be susceptible to this since it isn't (?) bowden.

Maybe you could post your start G-code (and a bit of the first layer) so we can see what your printer is actually doing.

Hmm, just to be sure, do you mean the plastic is oozing from the tip of the nozzle (normal) or is oozing out from between the nozzle and hot block?

As the filament in the melt chamber heats up, it's going to inevitably ooze a little bit.  Make sure you watch for this and clean it off as the hot-end heats up, and setup you slicing software to print a skirt, which will print a few loops around the outside of your print, separated by a few mm, to deal with ooze and get filament flowing properly.
If it oozes a lot, try reducing your print temperature a bit.

I would even say it's good to reduce temp as a first step, then when ozzing is slightly reduced you could consider skirt as Ian Williams said. Why? It's because skirt is time and material consumming, so it's better to have as less skirts as possible (if it's used only to stabilize extruding process)

The material and time used when printing a skirt are negligible.  It's better to stabilise the extruding process to make sure your first layer is good, than to worry about a few seconds of time and a tenth of a gram of plastic.

He he - I fell I misdescribe it. Of course it's good to have stable extrusion but as the temperature is too high the first step is to reduce it so it won't ozzing that much. Heavy ozzing is a signal that there is something wrong so reducing temp is to fix it and when it's fixed then it can appear that many skirt loops is unnecessary. Let's say - you can first patch the tire and then remove the nail but it's better to do it in the oposite order ;)

One possible solution is to "park" the hotend on the print bed as it is heating up. The bed blocks the nozzle, and prevents ooze from coming out. If any does come up, it tends to stick to the bed, not to the nozzle. You can do this by including an appropriate G1 command in your start G-code.

In general, it's a bit normal to have some filament ooze during warm-up. However, if it seems to be an abnormal amount, you may want to consider reducing your target temperature.
Keep in mind that ideal extrusion temperatures are subjective to the source of your filament. Not all filament is of the same material quality and differing degrees of purity. Sometimes, the same filament will be of different quality from the same source. It might be worth dedicating the first bit of each spool to a bar test to determine what the appropriate extrusion temperature should be.
A simple test would be to use the control panel on your machine or use your software (whichever is easiest for you):

Manually set the extruder to extrude filament
Stop the extruder
Clean excess material from nozzle
Watch for ooze
Gradually reduce the temperature
Repeat until the amount of ooze is an appropriate to your liking

Also remember that there will be some left-over material from a previous spool when swapping spools.

As others have said, printers ooze when heating up. I keep a business card by the printer and do a wipe on the nozzle just before it starts the print.


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What are the costs per meter of filament for PLA, ABS and PET?
My Craftbot Plus Craftware slicer estimates cost per job based on filament prices I add as parameters.  What costs per meter would you use?  I created spreadsheets to calculate this for 1.75mm diameter filament and arrived at PLA = 6.6 cents per meter, ABS = 6.1 and PET XT = 18.6 cents per meter.
Edit:  thanks for feedback!  I paid \$22 per kilogram for PLA and ABS.  I paid \$57 for .75 kilogram of Colorfab XT Black.

You might want to specify 1.75mm or 3mm filament. Although it's easy enough to calculate both.

A quick note from the economist part of my brain: While the raw material cost (and energy, etc.) is a contributor to product cost, the product price has to be based on consumer demand.  Craft fairs, and etsy.com, are littered with stuff priced by labor cost and unsold because nobody wants it.

I pay 36 euro for a spool (2.85 mm) of 90m PLA. That is 0.4 euro/meter. And that's a fact. And it's a lot higher than the numbers you guys are stating here.

This strongly depends on the cost of the spool in question. Prices are not consistent among materials at all; a spool of ABS can cost anywhere from \$15 to \$60 and the same price range applies to pretty much all other plastic.
For the purpose of this question I am going to assume that a 1 kilogram spool costs \$25 (regardless of material) but you can scale the figures to what is appropriate for your brand of filament.
ToyBuilder Labs lists the density of ABS at 1.04g/ml, whereas PLA is somewhat more dense at 1.25g/ml. As such, a 1kg spool of ABS would be 400 meters (1.75mm filament) or 156 meters (2.85mm filament). PLA would come out to 333 meters (125 meters for 2.85mm filament)
We thus have the following costs (cost per meter for 2.85mm filament in parenthesis):

ABS: 6.25 cents/meter (16)
PLA: 7.5 cents/meter (20)

The density of PETG is roughly the same as PLA, so they have the same cost per meter (for similarly priced spools).
In general, to compute the cost per meter, you would use the following formula:
$$[\text{\$/m}]=[\text{cost of 1 }kg] \times [\text{density in }g/mm^3] \times \frac{[\text{diameter in }mm]^2\ \times \pi }{4000}$$

Thanks Tom, good info.  I googled PET density and saw 1.38 grams per mm^2 while PLA was listed as 1.25 g/mm^2.  If so, that would make PET around 10% more expensive.  Colorfab XT is much more expensive.  The results from it are excellent.  I'm still a newbie.  :)

@DennisRose - PET is more expensive for the same volume of filament.  In reality though, you may use different materials in different ways.  For example: since PETG is notoriously a tougher material than PLA, you may end up using a lot less material by printing in PETG (say: infill 20% instead of 40%) than using PLA, so you may actually find that using PETG is in certain situations cheaper than using PLA.  Also (unrelated) you may be interested in checking this out.

The simplest method is to divide spool price by its length. That's obvious I think. If PLA 1.75 (1kg net) has about 120m length and it costs 16usd then it looks like 1m costs arount 13c. =price/length
I think everyone can buy different filament at different price from different vendors so there is no good general price to enter into your slicer app. It has to be calculated each time you use new filament.
There are also other parts of the price. Electricity, time, wear, depreciation, know-how even the rent is some part of the ending price of the final product. Of course most of them are incalculable as they are permiles or so. But if you don't plan to sell it you can base on the filament price only.

+1 For mentioning additional costs. Further more time might be a factor to consider: both the time required to print, but also the time you personally spend to prepare, trial and error, and so on.

The spools I have bought report weight but not length.  How do you get length info for spools you buy?

@DennisRose If spool doesn't have it specified on the label then you can ask vendor or google it. Rewinding with measuring is definitely bad idea.


text:
Prints get really messy for no apparent reason
I have a serious problem and I can't find a way to solve it because I have no idea why is it happening.
For some reason the things I print get really messy, like a mountain range growing on the print. It looks like overflow but it can't be because I'm already using 0.82 flow modifier and if I go any lower the printout will fall apart as the extrusions won't touch at all. I've double checked my extruder steps and my filament and also my nozzle width, all are set up correctly. The whole thing looks like the printer is over-extruding just in some parts of the print.

It definitely looks like over extruding. But similar effect can appear with proper extruding (or not too much exceeded) but with too high temperature.
If it appears only on some parts of the first layer then it can be:

bed leveling issue (or eventually bed is bent)
caret mechanism issue (dispositioned/bent)

You can also check different speeds just to be sure.

Your printer could be calibrated too close to the bed: if your slicer is set to use a 0.4mm first layer height, but the printer actually moves the nozzle 0.2mm from the bed, then you will get this result.
If this is the case, the first layers look over extruded and squashed, while layers after sparse infill has been printed will look fine. The support structure will in this case give room for the extra filament, making the extrusion look normal again (although it probably was fine all along).

That might really be the issue. I'll look into it

This is happening on the first or second layer, correct? It looks like your nozzle is trammed too close to the build plate. If there is less gap between the nozzle and bed than the slicer expects, it will over-extrude the first layer. That tends to produce "bacon" patterns of ripples on the bottom of the print as the plastic gets unevenly squeezed out to the side of the strand.

You beat me to it by 3 minutes! :-)


text:
Bed leveling method not working with Repetier firmware 0.92.9?
I homebuilt a delta 3D printer (like Kossel mini) with a Z probe near the hotend with manual deploy and RAMPS 1.4 board:

I configured the Repetier firmware with the online tool;
All my endstops (included the Z probe endstop) work in reverse mode, so I reversed the endstops triggering option;
I enabled Z-probing and set the BED_LEVELING_METHOD to 1 (n*n grid);
I set Z_PROBE_REPETITIONS to 3, and;
Finally I downloaded it and uploaded to my Mega 2560.

Then I tested it inside Repetier-Host and all seems to work well (homing, moving, extruding) except for the Autobed leveling method.
Specifically, it always starts measurement of 3 Points (with 3 probe repetition each) even if I change the type of measurement.
It never does a grid measurement or a 2 points mirror measurement.
I also tried to re-upload the firmware with EEPROM_MODE to 0 but didn't work.
Does anyone have the same issue, or can explain to me why this happens?

As a guess, you are using the wrong command. If set for n x n grid, you get 3 point measurement with G29, but that is not auto leveling, it is just setting Z height - based on average height at 3 points.
What you need is G32 S2 with S2 to store result in EEPROM (and therefore you should have EEPROM enabled with auto leveling. It is also used to store endstop offsets).

Ho thanks man! I thought it was the same as the Marlin firmware code. So the right procedure is: G29 then G32 and at the end G33 ? Please can tell me where can i find a reference to all codes in the Repetier firmware? thanks

No, skip G29 completely, no need for that. G32 S2 is all you need. G33 makes sense only after you have calibrated parameters to best fit bed. The less it has to do the better or you get wavy surfaces higher where it is disabled.
All gcodes can be found in Repetier.ino file with description. www.reprap.org -> gcodes has also a good overview of most commands.

Delta bed leveling has been dodgy in Repetier for a long time. There are a number of fixes occurring in the dev branch right now (June 2016) if you look at Github. So it's getting better, but I wouldn't call it mature yet. (Delta auto-calibration is one of the only big shortcomings of Repetier, in my opinion.)
The problem with approaches like bed plane compensation and grid/mesh leveling for Deltas is that they don't fix print geometry errors caused by imprecise printer construction. They just help get the first layer down. What I would recommend is to use one of the non-Repetier delta auto-calibration techniques available in order to get your firmware settings correct, and then you won't need to use "slap a bandaid on a calibration problem" solutions like grid leveling. Two popular options:

Load Rich Cattell's Marlin branch, perform auto-calibration, record the adjusted values, and then load those parameters into Repetier. This will usually work well enough that you don't need to attempt any kind of auto-leveling in Repetier. (I don't recommend actually printing with Marlin on a Delta due to lack of performance optimization. Repetier can print much, much faster while managing more features like LCDs. Marlin gets bogged down doing all the Delta kinematics math unless you print very slow.)
Use David Crocker's awesome online delta calibration tool. I'd recommend using six-factor calibration with 10 probe points. This is the manual version of the auto-calibration technique built into dc42 RepRapFirmware, and it's practically magical compared to the routines built into Repetier.

Sidenote: Grid leveling can be a very useful technique for large printers where bed flatness is difficult to achieve. It's just very limited as a way to deal with delta calibration problems.


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da Vinci Jr. nozzle diagram
Has anybody taken apart a da Vinci Jr. 3D printer nozzle?
My first time trying to clean the nozzle after it jammed, I broke off the filament immediately before it gets heated, inside the nozzle assembly. The XYZprinting video, "da Vinci Jr. 1.0 - Advanced Nozzle Cleaning", shows the filament coming out easily when heated, but now I'm seeing that I should have cut the filament by the feeder and pulled it out after heating.
I have a long length of wire that is similar to the tiny cleaning wire that comes with the kit. Is it safe to heat up the nozzle and push the wire all the way through?
I tried pushing from the other direction with the large cleaning tool (as shown in video). I also tried heating the tip of the filament and pushing it to the jammed filament inside the nozzle and reconnecting it. It held a while as I tried wiggling it when heated but did not break the jam loose and broke off again...
What should I do?

If the wire is the same diameter as teh cleaning wire (or less), then OK to use.  There's a number of kits out there which provide what are essentially  ultra-small diameter drill bits for cleaning nozzles.   For that matter, replacement nozzles are pretty cheap, tho' I'm not knowledgeable about compatibility with daVincis

OK well I tried with a drill bit, not long enough so I unscrewed the small gromet bushing that holds in the feeder tube one the top of the black nozzle assembly box ( it sticks up about a quarter inch, it looks like stainless steel and has a black rubber washer gromet connected to the top to connect feeder tube.) Then, after trying again (no luck) I noticed the female threads that were inside the assembly were now gone... The top connector piece was screwed onto a small nut and now it is trapped inside the black box....

Now can how can I take the dang thing apart or do I even need extra small torq bits???     please don't reply unless you have dealt with this machine before I'm trying to fix the one I have if possible and not break it

Have you managed to resolve your issue yet? If so, could you post the solution in an answer? I think that a tried, and tested, solution would be rather useful for other users. Have you tried emailing XYZprinting tech support for a solution?

After watching the video, it looks this is a Bowden style extruder.  The extruder assembly is encased in the black box the OP mentions.  The assembly is user removable.  It appears they also include two cleaning tools

Small (0.4mm?) wire to clean the nozzle tip
Large (1.7mm?) rod for pushing filament down that is stuck in the cold end

It appears the OP tried accessing the filament in the cold end by removing the fitting at the top of the assembly without opening the assembly.  Unfortunately that caused the nut holding the fitting on from the inside fell off.  At that point he was in a bit of a mess.
I believe the manufacture's intent is to "ram" any broken pieces in the cold end through the hot extruder by using the provided rod and pushing while the extruder is on.  It seems that it should work but would not be easy to do if the filament broke off outside the extruder (which seems to be the case).
At the point he left it, it would seem that he would either have to do surgery or replace the extruder assembly.