Should I use different nozzles for different materials? I know I should use different nozzles for filaments that use vastly different temperatures but what about filament types that use similar temperatures?

For example, PLA and PLA composites like ColorFabb Woodfill filament.  Should I use a separate nozzle for that?

There is absolutely no reason to use different nozzles, not even if filaments do require different temperatures.

The only exception is when printing abrasive filaments (such as glow-in-the-dark and carbon-fiber) in which case you should use an abrasion-resistant, stainless steel nozzle. This nozzle can also be used to to print "regular" filaments but a regular brass nozzle has slightly more favorable properties if you do not require abrasion resistance.


Why all the excitement about linear rails? Whenever a 3D printer that uses linear rails is announced (case in point: the cetus), the Internet (well... at least that corner of it dealing with 3D printing) gets abuzz with excitement.

I researched a bit the topic myself, and while I understand that linear rails can be produced to a fantastic degree of precision for super-heavy machinery, it escapes my comprehension why they are considered superior "by default", relative to the classic linear bearings on a shaft.

3D printing is a lightweight application, and the motion of at least 2 axis does not happen against a solid surface (where you could bolt a linear rail every few cm) but suspended between the 2 ends of the axis.  Furthermore, the internals of the bearings used on linear rails are substantially identical to those used on a shaft.

The cetus site says under the heading "Quality Linear Rails":

  Self-lubricated | Maintenance Free | High Precision | Long Lifespan | Quiet

but this - in my experience - can be said of "Quality Linear Bearings on a Shaft" as well, and in some cases even bushing deliver to a high standard on 3D printers.

So, what am I missing?

The following is a compilation of the input from a number of sources.

Linear rails in general are mechanical components that - when designing equipment - offer great flexibility.

The profile of the rail can be designed in nearly infinite ways. This in turn allows for:

Different levels of stiffness in different directions (for example you may have stresses only on a given plane, or you may actually want the rail to slightly flex in one plane but not in another one).
Placing the surfaces for the rollers strategically, for example in a location that is unlikely to get contaminated, or where the maximum force will be applied.
Curved paths, so that the carriage can move along a line that is not straight.

Because the contact surface between the rollers and the bearings is flat, cylinders can be used instead of spheres.  This in turns diminishes the mechanical stresses, and the amount of play, increases longevity and allows for more bearing capacity, among others.

Linear rails can be anchored along their full length, rather that at their extremes, thus increasing the accuracy of their positioning, their stiffness and their bearing capacity.

Linear rails can be machined while pre-loaded, thus achieving maximum accuracy when in use, rather than when coming out of the factory.

The bearings on a linear rail only allow for one degree of movement.  There need to be two rods with linear bearings/bushes to achieve the same result.

All that said, when it comes to the specific application of consumer-grade FDM 3D printers, it seems that none of the above is very relevant, nor confers any real advantage to the printer in terms of quality of the final print:

the mechanical stresses involved in 3D printing are very small,
the movements all happen along straight lines,
most of the axis cannot be anchored to a large, rigid body,
...

On the other hand, the design with rods + linear bearings is cheap, effective, simpler and lightweight, all characteristics that are highly desirable in a 3D printer.

All in all, it seems that there is no good reason to prefer linear rails over rods in general.

Still, there may be specific designs that may benefit from their adoption. I postulate that the Cetus printer linked in the question may be such a design: the cantilever arrangement of its axis - for example - is well served by the fact that a single rail locks movement in all but one direction, and the orientation of the X rail offers maximum rigidity against the action of gravity.


Anet A6 ERR MAXTEMP BED error Out of the blue my A6 printer displays a ERR MAXTEMP BED error and shows about 100 degrees on the bed even when just powered on.

A quick thermistor check shows that it's working properly : about 80 kOhm at room temperature, similar to other units (didn't bother to really check the specs).

Swapping the bed thermistor for the head thermistor connector does not change the temperature readings : the one connected to the bed input gets 100 degrees, while the other one works as expected, proving that the connector and thermosensor are ok.

It has to be in the board. How do I fix it?

I'm posting the answer here hoping that will help anyone that encounters a similar issue. A post on another site indicated that these boards are known to be problematic.

After some digging, I came up with the schematics of this part of the mainboard :

I'm not an electronics genius, but clearly it's not the capacitor; so that leaves the pull-up resistor or the microcontroller.

Since the printer is already unusable, no harm in trying to replace the resistor, which is located just next to the connectors; for the bed it was the second from left, but if you encounter the same issue with another input, you may need to locate the proper one.

Make sure you have the proper tools and knowledge for removing and soldering SMD components; in my case it was a 4k7 resistor in 0805 footprint.

Bottomline : replacing a less-than-one-cent resistor saves a month of waiting for the delivery of a $25 board.


Ultra high precision and accuracy printing I work in a teaching hospital and we have a research project we're interested in pursuing.  We'd like to 3D Print tubes we'd implant into rats to help with nerve regeneration.  We're interested in the shape of the tubes right now, more so than what material it is or whether it's biocompatible etc..

So this question isn't necessarily about what type of plastic or whatever we should print in.  My question is more so:

  We'd like to print a tube that's 1 mm in diameter, about 1 cm
  long and has as many micro "tubes" crammed through it as possible,
  something like this:

I currently have a Stratasys j750 in my lab, a UPrint Se and a Prusa i3 Mk3s.  They all work well but for the detail I'm looking for, come up a bit short.  They have advertised accuracies of 14 microns (well, the j750) but thats just in the z direction, x and y are more like 200.  If I went to get PRECISE, what technology should I look into?

This is an interesting question. A good thing to note when we start talking about SLA and other jewelry grade 3d printing, that you will have to factor in the materials toxicity when we start talking about medical applications. You can also look into DLP 3d printers but they will not have as good quality.

What can help you right now is these SLA printers I see that form 3 has 25 microns, with a laser dot of 85. Well within your tolerances. Just make sure to get dental grade or medical grade resin.

Note that if there are bends, then you will have issues with SLA printing, depending how steep the angles are.

There are other technologies, such as metal 3d printing or SLS printing, that will likely be out of your price range such as the HP Metal Jet that can do 21 -xy by 50 -z microns. Or binder based 3d printing which will have the best internal geometry, as powder will act as support, and is easily removed.

There are many specifically in the bio printing area that might be what you are looking for as well, this is more an alternative. You can look into what the researchers at Penn has been doing, where they have been using Sugar to create vascular networks. As far as I know they do not sell it as a product at this time. Here is more information about scaling vascular networks

See here for more information about other printing technologies


What should I use to clean buildtak(knock off)? My printer came with a knock off BuildTak like build surface. What can I use to clean it? I don't want to damage it.

Isopropyl alcohol (IPA) is the general recommendation I've heard and it works well for me.


Teflon tubing in nozzle throat coming out? I have a HE3D prusa XI3 printer with an MK8 extruder. While printing or testing, the extruder makes a clicking noise as if the filament isnt getting hot enough to extrude. I began my investigation and read about many reasons why this could be happening. Eliminating most of them, I finally took off the fan on the extruder and looked at it while it was trying to extrude. I noticed the teflon tubing and tried to push it back into the throat. Then the extruder worked fine. I put everything back together and began testing again. The clicking came back,  - I then took the fan and heatsink back off and there it was again. Pushing back down and this time extruding some material and noticing the tubing slowly coming up. Is there anyway to fix this without upgrading to a better hot end?

It looks like you got too tight nozzle, too cold hotend or extruding speed is too high (all could be in the same time of course).
As filament goes into the teflon tube (coldend) and then into hotend it doesn't have enough time to go out throught the nozzle. So it causes that melted filament accumulates in hotend and pushes out teflon tube.

Check application and arduino settings for

nozzle diameter (increase it), check if it's not plugged with something inside
hotend temperature (increase it), check for your filament settings
extrude ratio (decrease it), check also gearing on extruder motor


Which is a more accurate linear motion system? If someone looking for accuracy, which is the better linear motion system:

Maker slide,
Smooth rod - bearing,
Linear guide way,
V slot,
Open rail

Please let me know if there's a better one other than above list.

I used a few different linear rail systems in my build:

plain smooth rods for Z motion
smooth rods bonded to a T-haped steel base for a 1200mm Y axis (similar to those at https://cdn.automationdirect.com/static/specs/suremotionlinear.pdf)
igus "low profile linear slide" for X (https://www.igus.com/drylin/profile-rail-guide)

They all seem to work pretty well. The one problem I had was with the igus slides, which I found had a little too much play -- so each change of direction on X had a slight backlash, from the "cars" twisting a tiny bit within the rails. I improved that with careful tuning: shifting the rails a tiny bit farther apart, so they kept the cars under a little tension against the inner sides of the rail -- some call this "preloading".

I think systems that use actual bearings should generally be more accurate than spring-loaded slides. But the igus rails are still pretty good, and they're quite light, compact, and reasonably priced. I still use them, though once in a while I think about swapping them out to do a serious comparison.

The rails aren't the only factor in accuracy, though. I can't detect any play or warp in my Y rails, but that says nothing about accuracy and repeatability of motion along them. That's controlled by the motor and the belt, leadscrew, or other things actually moving them. Leadscrews, in particular, vary quite a bit in accuracy, depending on the shape of their threads, the kind of "nut" riding on them, and other factors.

You can even make your own leadscrew system from just a threaded rod and a nut -- but those threads are not the same, and they allow far more play than a real leadscrew does. Nice article on the "backlash" problem at https://www.liutaiomottola.com/Tools/Backlash.htm.


What's a good way to secure bushings in a 3D printed part? I'd like to secure bushings in 3D printed parts. They would be used for a drilling jig. I've seen heat-set inserts, but they've all had threaded interiors. The best idea I can come up with is printing the plastic hole several thousandths of an inch larger than the bushing and applying a lot of epoxy to the OD of the bearing and inserting it. Is there a better way?

As an aside, I had a hard time finding proper tags.

If the outside of the bushing will bond well to the epoxy, your method is simple and likely to be effective.

You could use the same method used for threaded inserts by roughing the exterior of the bushing, heating it and forcing it into a correctly sized hole printed in the model.

The threaded inserts are knurled or otherwise textured to provide stronger bond with the melted plastic. Knurling your bushing is more complex than a good epoxy bond.

I've discovered a product called "castable bushings" which would appear to meet the above requirements for heated inserts:

The product listing indicates that these are used for drilling jigs.

It might be less messy but more expensive to purchase and use these as opposed to epoxy and a bit of sanding.


Creating "pie slice" in OpenSCAD? When making a cylinder, sometimes I need to only take a pie slice. I'm currently using this neat trick to make pie slices for angles under 90 degrees. However, I have need of a few angles over 90 but under 180 degrees. Is there a way to generalize/extend this to work for these bigger angles?

module pie_slice(r=3.0,a=30) {
   intersection() {
    circle(r=r);
    square(r);
    rotate(a-90) square(r);
  }
}

pie_slice(r=10,a=15);

My current workaround is to use union instead of intersection. Unfortunately, that means I have to use an if clause which makes the code have two paths instead of one clean approach. Also, unlike the above method, this does not result in a clean cylindrical shape but must instead by combined with a proper cylinder to get the final pie slice

   size = length + 2;
    if (angle_deg <= 90) {
      translate([0,0,-1])
      intersection() {
        cube(size);
        rotate(angle_deg-90) cube(size);
      }
    } else if (angle_deg <= 180) {
      translate([0,0,-1])
      union() {
        cube(size);
        rotate(angle_deg-90) cube(size);
      }
    } else {
      echo(str("FAILURE - Angle cannot exceed 180"));
    }


Configuring BLTouch with Marlin firmware Has anyone configured BLTouch with Marlin firmware?

I could only find videos about older firmware version. I followed this document. To avoid causing any damage to the printer, I removed all connections, took the board out and connected a stepper to Z-axis terminal and BLTouch to Z-min and servo 1. All other axes are not connected. X-min and Y-min end stops were shorted using jumper (Mine is NC configuration).

After updating the firmware, I can move the X and Y steppers, but not Z stepper. There's a blue light glowing inside BLTouch, which turns off if I remove Servo connections.

The M119 command shows all end stops are open.

Do I have to change pull up settings of end stop?

I cuurently have:

Marlin 1.1.6
BLTouch Classic

Here's my configuration file

For security reasons, you cannot move Z until home position is applied to X, Y and Z.

With the level sensor attached, we need to home X and Y, and then Z will be homed in the middle of the bed (as configured). Execute G28 to home all axis and then you shall be able to run 'Z'.

To test that, you can unplug just steppers (with power switched off to prevent damaging the stepper drivers) and move X and Y manually to home position, then just give a touch to the BL sensor (when servo/pin) is deployed to confirm home position.


Ender 3 unknown (maybe bed leveling) issue I halfway feel like I walked into a landmine, neighbor's kid saved up and bought an Ender 3 base model printer.  Just before it was given to me he installed a BL touch I bought him in exchange for him printing some parts I was modeling and so our story starts...don't think I can go into my full sob story so I'm going try and cut to the chase but I have little knowledge of how this is put together and coming in in the middle and backpaddling whether is was put together correctly.
As a 3D modeler I attempted to print a demo file or two in preparation to print a case for a raspberry pi camera I've been working on during COVID.  At some point during the print while I wasn't around the bed flew off, and there was an inch of plastic melted around the head.  Long story short I spent the last week finding, buying and replacing the whole hot end assembly as it was cheaper then repairing it.  So now I believe I'm back to square one.
While watching something print, I noticed the PLA wasn't getting bunched off on one part of the print so I stopped it before a repeat of earlier in the month happened.  While sitting on the floor I began to notice the right side of the bar where the hot end/nozzle attaches is about 1 cm or so higher then the right.  As I have no frame of reference I'm hoping someone can confirm whether that should be the case.
Raising the Z to the top and measuring to that cross bar  I don't know that it's the bed but I don't have a small enough level to put on the bed.
I'm seeing if I print something like a calibration cube it's printing OK, but if I go for something wider like 3D Benchy or my camera case the filament only touches on one part of the bed.  This is occurring on both the original bed and the glass bed I installed and readjusted the Z for.
Sorry...Hope that's not TMI, there's a lot going on.  Also I'm using a spool of Hatchbox PLA if that matters and the new hot end is a Creality one from Microcenter as I didn't trust what was on Amazon to be 'authentic'.

Non-square gantry is a common problem with the Ender 3. You should be able to compensate by adjusting the bed leveling screws so that the nozzle at Z=0 is touching the bed at each of the four adjustment points. This will leave some skew, which you may or may not care about. But the right thing to do is leveling the gantry.
Both sides' Z carriages have some play in how the gantry mounts to them - the holes are larger than the machine screws that go through them - so after loosening the screws you can make adjustments. The screws on the side with the Z motor are hidden between the carriage and Z axis extrusion it rolls on, so to adjust it you need to roll the whole assembly off the top of the printer (with the cross beam at the top removed). Since you can't tighten it in-place, you just have to do your best to get it straight before putting it back on. The unpowered side, however, has screws that are reachable with the whole assembly in place, so you can square the gantry with the Z extrusions before tightening them.
Keep in mind that the whole Z axis system is severely over-constrained, with 6 wheels where 3 should suffice to constrain it. People have a lot of different ideas about how you should deal with this, and I'm still not sure what's best, but I think you want to get each of the V-roller sets tight (using the eccentric nuts to adjust the inner wheels) before leveling and tightening down the gantry. Otherwise the wheels may have uneven tension, causing the assembly to want to twist.


Is it possible to run 2 Ender 3's off one power supply? I have 2 Ender 3's and I am limited to wall sockets to power both the printers at the same time. So I was wondering if it was possible to wire both the printers to a single PSU? As the printer uses a single xt60 connecter for power to the mainboard, so there is a spare screw terminal on the PUS where the xt60 for the other printer could be screwed in. I am just afraid if I run both printers off one PSU, I might see some magic smoke or else the psu may not be able to provide enough power for them both and may cause print/power failure.

The heated bed alone draws 220 W of 24 V power, so I'm going to say no, you shouldn't attempt to run two Ender 3 machines from a single power supply.
Instead, because the whole machine only draws about 3.5 A at 115 V (or half that at 230 V), you should consider installing a power strip or (better) a small UPS to both power both machines from your existing outlet(s) and also protect the machines from power surges and short power interruptions.  You won't overload your outlets, and you won't risk burning out a power supply by drawing twice the power it's built to provide.


Always keep printer hot and ready to print We are using a Prusa i3 MK2 printer in a structural design firm to print the buildings we design as well as print individual panels and components. Projects can have 100s of pieces that need to be printed quickly, but the printer cools of quickly after the print finishes. When we go to start the next print we have to wait 10-15 minutes for the printer to warm up again.

We tried preheating it using the built in function hoping that it would keep the heaters on after the print is complete but had no success.

Is there any way to set the printer to stay warm after the print to be able to quickly print back to back?

Just set values in your end code for your slicer.  Set the bed to the temp you use, set the nozzle to roughly the Tg temp of the filament you use.  Typically the bed heatup time is the worst offender here.  I wouldn't keep the nozzle at extruding temps, though.


Using auto-bed leveling, do I need to initiate G29 before every print? Various methods to scan the top surface exist to improve the bed adhesion to prevent prints to come loose from the bed during printing: e.g. BLTouch and clones or inductive and capacitive sensors/probes.
In order, for the print head, to use this so-called auto-bed leveling (ABL) you need to add the G29 command in your start G-code of your slicer.
Is it necessary to call G29 before every print?

The rationale behind this is that scanning the surface takes up some time, certainly on very short prints, it would be great if the surface geometry could be saved.

No, it is not necessary to call G29 before every print to "auto level the bed" 1) provided that:

the bed surface has not changed (e.g. large load or force has been exerted on the build platform, leveling screws are accidentally adjusted, etc.),
the carriage of the hotend is stable (some printers, e.g. the cantilever type, or single side Z lead screw driven printers are more prone to an unstable or level axis), and
the scanned surface geometry is saved in the controller board memory.

There are several solutions to solve this. You could manually run the G29 command once in a while storing the scanned surface with an M500 command  to save the mesh to the EEPROM (memory) of the controller board (this can be done from the printer controller display for Marlin operated printers, an interface like a terminal or a print server application, or from pre-stored .g/G-code files on an SD card). If you use the SD-card, note that it is possible to auto-launch G-code files from the root of the SD-card upon inserting.
Do note to remove the G29 command in the start code of the slicer. The G29 command needs to be replaced with M420 S1 for Marlin firmware operated printers. This command will load the saved mesh at the start of the print from memory. This is especially useful when using a large amount of probing points (e.g. a large bed mesh using a 10 x 10 mesh of 100 probing points, to ensure the mesh is up-to-date, once in a while initiate the scanning sequence to store an updated mesh).

1) Please note that auto-bed leveling might be confusingly indicating that some magic leveling of the build platform/surface itself is taking place (this is also possible in Marlin when there are multiple Z steppers and lead screws used), but, that is not actually what is meant with this phrasing. The process of the auto-bed leveling actually scans the surface of the build surface and compensates the height of the print head/nozzle during a predefined printing height (usually 10 mm, set in the firmware or through G-code: M420 Z10 ; Gradually reduce compensation until Z=10), during this printing process the nozzle gradually be less and less compensated.


Starting G-code for auto Z probe offset So, I like to take off my glass build plate from my printer bed because I don't like to put any force on the bed bearings but this presents an issue. I have an inductive bed leveling probe and each time I remove the plate the Z offset seems to be off on the next print.

Instead of re-leveling my bed and setting the Z offset by hand, I thought of adding starting G-code to do that for me but I've hit a snag. I have an Ender 3 and use Slic3r.

The sequence of events I would like is as follows:

G28 - home axis
G0 X150 Y130 Z5 - Moves to X150 Y130 Z5
G30 S1 - Performs a bed leveling probe at the current point. This raises the head 10 mm and stops when the probe is triggered. The current Z height this stops at is what I want for the next command.
M851 Z[insert Z height from prev command here]

I know Slic3r has these placeholder values for some commands like M109 S[temperature_0] in the square brackets. Is there one for the current Z height?

The inductive sensors trigger to the metal plate under the glass bed. This implies that if you remove the slate of glass, the distance between the trigger point and the print bed is increased by the thickness of the glass slate. But, the trigger point is still exactly the same as if there were a slate of glass (as it triggers on the metal bed underneath). This extra distance need to be compensated for.

The method you are using is incorrect in determining the distance between the nozzle and bed with respect to the sensor trigger point. This answer on question: "Z Offset on autoleveling sensor setup" describes how you need to determine the distance between nozzle and bed from the trigger point. It includes a manual step to lower the nozzle a paper thickness above the build plate.

If you insist on using G-code (e.g. in your start G-code script), you can redefine the Z=0 level by adding a G-code G92. In case of a 3 mm glass plate, you should add after the homing (G28) and probing of the bed (G29) the following:

G1 Z0  ; This will move the nozzle to Z=0 as if there was a slate of glass,
         but in fact it is still 3 mm offset
G92 Z3 ; This redefines the old Z=0 (with glass) to be Z=3 mm


How is a Thermistor supposed to be installed between Heated Bed and the Glass? opposed to what the title of this question might impose, I'm not new to 3d printing itself and have operated more than one printer for years, however, I feel dumb with installing the Thermistor on this new Heated Bed I got from RepRap.me: Aluminum Heatbed MK3 400x300

The old Mk2b 214x214 Mendel/Prusa heated bed that I have been using for quite a while now has a through-hole in the center, where the thermistor-leads could be fed to from below.

On this new heated bed however, there is a lowering in the very center of the Heated Bed to place the Thermistor in, yet the pads to connect the thermistor leads to right beside it are level with the rest of the Heated bed.

I tried using just a tiny amount of SMD solderpaste and just soldering the thermistor leads as flat as possible to the pads, nevertheless, the glass plate on top is not laying flat and stable on the heated bed with the thermistor installed.

Any suggestions are greatly appreciated on how improve the thermistor-installation onto this heated bed!

Try to use a silicone heat conductive pad between heater and glass, where you can make a hole for the sensor. It also helps to improve the contact between aluminium heater and glass, which otherwise may be inhomogeneous (as expected between two quite rigid materials).

They sell them in rolls and you can choose a 1 mm thick one or even 0.5 mm. They are "sticky" but they don't have glue, so you will be able to separate the glass from the pad, even if not so easily as it would be with a clip.


Prusa i3 MK2 Heated Bed Thermal Runaway Problems I'm having an issue with my Prusa i3 MK2 MMU.

It starts printing just fine, and everything gets up to operating temp quite quickly. However, after printing the first few layers, it seems as if the heated bed can't keep up with the demand, and its temperature starts to drop, first it can barely hold 80 °C and then it slowly drops down to 77-76 °C before the printer shuts off due to BED THERMAL RUNAWAY.

The LED is continuously on for the bed, so it seems to be supplying power when this happens. Setting the printer down from high power to "silent" helps a bit, so could this be that it is not getting enough power?

Ambient temp is around 17 °C.

The local library makerspace (prior to COVID-19 shutdown) has a Prusa i3 MK2 (no MMU) that had a similar problem. The model being printed was relatively small, compared to the bed and was being printed nearly atop the temperature sensor.

The part cooling fan was cooling the bed sensor while the rest of the bed was not being used.

Moving the model away from the sensor resolved the problem. If you're printing in the center of the bed, consider to re-slice in a position offset from the center.

If you are using the PEI sheet as the library machine is/was, consider to shuttle your prints around the bed over time. The library's printer wore away the PEI from always-centered prints. It had to be replaced after about a year. The replacement is going on two years with little complications.


Estimating filament consumption in length per time I printed a lot of models in last month. I spent 2 kg filament in total. I want to know how many hours have been passed while printing. As far as I read, 1 kg PLA (1.75 mm) is about 110 meters long. My default print speed is 70 mm/s. The nozzle diameter is 0.4 mm. The nozzle multiplier in the simplify3d is 0.9 .
In a very basic math,
220÷(0.7×0.04÷0.0175×0.9)=~ 153 hours.
Is this correct?

Your math looks correct, and is also a good approximation for what I've seen in the first few weeks with my own Ender 3.
Another way to calculate (to check yourself) is to calculate the volume extruded (nozzle area times extrusion percentage times print speed -- be sure you convert everything to the same units!) in a given second, multiply by the density of your filament (common PLA runs about 1.2 g/cm^3), and get a rough figure for how long it takes to print a kilogram of filament.  Your actual print time will always be higher than this approximation, because there are moves during which the extruder isn't running, infill is often set to lower extrusion level, and of course there's setup and cleanup time to account for.


Cleaning IPA with the help of Mercury wash-and-cure? I have seen that you can clean used IPA from resin by putting it in the sun a while, making the resin dissolved in the IPA cure. Could I do the same thing just using the cure-mode in with the Elegoo Mercury wash-and-cure-station?

Based on the frequencies of most UV cure resins, your suggestion has merit. Other factors come into consideration, however.
These illumination devices have a limited life span. Running the UV diodes for the purpose of curing out the resin from the IPA will "use up" the portion of time otherwise useful for curing models.
Additionally, the UV light which would otherwise be "applied" to the surface of a printed model now has to pass through the IPA. While the IPA is perfectly transparent to the 405 nm used to cure resins, there could be attenuation and refraction by impurities in the liquid.
Sunlight is mostly free, broad-spectrum, and (on a sunny day) far more powerful than most affordable UV illumination systems.
In a pinch, sure, use the curing feature, but the sun is your cheap friend.


Is this the correct motherboard for my Creality CR-10S Pro V2? When trying to solve the issue described in this post I followed the advice in the accepted answer and I found that the timing pulley holes for the Y axis (to "secure" the pulley to the motor shaft) were only half drilled (!!!). I suppose that everything worked fine (even without blind screws) for the first month (probably because the belt was extremely tight) but just a bit of wearing and it started to slip.
While I already replaced the pulley I also contacted the Creality technical support to obtain (at lest! funny...) a reassurance that it didn't possibly stressed the belt or the bearing balls. My experience with their technical support has been horrible and I am still waiting (after weeks) my answer (probably it's easier for them to try to ignore their sloppy assembly and QA) but they sent me a procedure to follow to "debug" any issue with my printer.
One of the pictures in that procedure is this:

To my surprise this is the motherboard I have:

Now I am puzzled. Which one is the correct motherboard for the Creality CR-10S Pro V2 (not the old version but the newer V2)?
Is this just [another] sloppy mistake from the technical support or I do have the wrong motherboard? Differences with V1 are not many then I suppose it could even work with the old one...

The board that's installed in your machine appears to be the Creality v2.4 / v2.4.1 board, which is the correct board for your printer.
It is distinguishable by the 30-pin ribbon connector, which is used to connect to the rest of the printer.
The board in the tech support pictures is the v2.5.2 "silent board", designed for printers such as the non-Pro CR-10 series. It features two 10-pin connectors for the LCD screen.
It also uses individual connectors for all functions, so, contrary to the "Pro" boards, is also easily swappable with aftermarket boards.
A third type of board (e.g. v1.1.5) exists, mostly for the Ender 3 series of printers, which features only one 10-pin connector for the display.


Chocolate printing vs casting? I need to make chocolate busts.
Is it better to make silicon reverse of the bust and cast the bust or directly print it using chocolate printer (I prefer cost and process speed over quality)? I don't have chocolate printer so if this method will be better I will need to use some 3D printing service.
I need to make quite a large amount of the busts.

In my experience, direct printing of chocolate is tedious because:

It has to be around 88 C to melt; and
It doesn't solidify very quickly at normal room temperature.

Unless you can print in a chilled environment (freezer is better than refrigerator), you will likely wind up printing a chocolate puddle. Even then, you have to heat not only the reservoir but also the entire nozzle (or it may solidify in the nozzle).
Also, some chocolates have issues if they freeze or become overheated, so it's a very tight tolerance with the temperatures.


How to obtain high resolution prints in a shorter period of time? When I've printed an object I've had to choose between high resolution and quick prints.  What techniques or technologies can I use or deploy to speed up my high resolution prints?

You could experiment with slicing. For example, you might not need high resolution all over the object, but you can speed up some straight parts by using greater layer high there. See a part of Slic3r manual about such thing.

It is also possible to print thicker infill every Nth layer, see Infill optimization in Slic3r.

Other slicers might have those features as well.


Preview 3d printing process Is there any type of software in which you can animate the way the .stl object will be printed?

I'm not talking about what the end result looks like. I'm talking about a tool which acts like it's printing the given object as an animation.

I know it somehow depends on your printer but is there anything I can use?

You may wish to consider Craftware for your purposes. It's a free program in beta form that does provide a tool-path animation for printing the layers. It is not so much specific to a printer as it is configurable for your own requirements. The video shows what I believe you are seeking at about the two minute point.

Simplify3D also provides such information, but is not a free program.


What material should I upgrade the teflon tube to? I'd like to print PET on an Ender 3 v2, but I see that some people recommend upgrading the hotend because it will melt the teflon filament feeder tube. I'm not sure if the hotend will even get hot enough to use PET, even though it's listed in the specs for the printer.  I didn't know Teflon could melt, if that's the case, should I get rid of my teflon cooking pans?

What is the max temp range for a stock Ender 3 V2?
What material tube should I upgrade to?
What are the benefits of an all metal hotend as far as hotter temps?  Why is that the recommended solution for PETG printing?

The Ender 3 (original, pro, or v2) does not need any modifications/upgrades to print PETG. Temperatures of 230-235 °C are sufficient for PETG and well under the 250 °C that's not recommended to be exceeded on a machine with PTFE lining all the way to the hotend. PTFE doesn't melt above these temperatures, but it does start to break down and release chemicals that can be harmful. Note that teflon pans achieve temperatures comparable to or exceeding what you'd print PETG at all the time while cooking, and especially if you burn food. The smoke point of peanut oil is roughly the same as the temperature you print PETG at.
If you did want to change it (I wouldn't recommend this) there is no different tube you can "upgrade" to. Instead, users who want to be able to print higher temperatures switch to an "all metal" hotend, which means the tube doesn't extend through the heatbreak to the hotend, but instead stops in the cold part, with a metal passageway for the rest of the filament's path to the hotend/nozzle. You still use the same PTFE before that, though. All-metal hotends are not necessarily an upgrade; they're a tradeoff. The PTFE tube all the way through is a highly desirable feature because it has very low friction and no ridge/boundary between materials for semi-molten filament to get caught on when retracting and unretracting.


Good sources of filament "sampler" pack? The local stores have started to stop selling filaments in the smaller 0.5 kg spools, and it's getting harder to maintain an assortment without buying lots of big spools.

I mainly just want a bunch of different colors (red, black, blue, green, etc.), ideally as a bunch of small spool "samples" or like a "sampler pack". -- Even if they're at .25 kg spool sizes... -- I don't want to spend a ton of money on buying and storing a ton of 1.0kg - 2.0kg spools.

I prefer to print in PLA, but ABS is fine.  I can only print 1.75mm filament.

The seller should to be able to ship to western US, and have filament of decent quality that's not going to ruin my printer.

What do you recommend?

Amazon, of course.   I found a pack of 20 colors, maybe 50g each or so, 1.75 PLA. (that link is direct to this product).

edit:

Well, dang,  I blinked at that particular item is off the list.  Here are two other multicolor packages currently available (2PM EDT 20 Oct 2016)

one , and  ...    two


Error "TMC2208 or TMC2209 on Z2 requires Z2_HARDWARE_SERIAL or Z2_SERIAL_(RX|TX)_PIN I am getting this error when I try to enable the Z2 driver for MKS Gen L V2.1
Could anyone help?
Error "TMC2208 or TMC2209 on Z2 requires Z2_HARDWARE_SERIAL or Z2_SERIAL_(RX|TX)_PIN
Thanks

Your question is missing important information, but I can try to figure out something. You didn't say what kind of firmware it is. I assume it is Marlin.
Your problem is that there are no Tx Rx pins specified for Z2 (because there is X, Y, Z, E0, E1 by default on the MKS Gen L board)
I assume you want to use the E1 driver for the Z2 instead of a second extruder. In that case, you have to tell the firmware that you want to use that driver for Z2.
Search the source code for file "pins_MKS_GEN_L_V21.h"
There should be E1_SERIAL_TX_PIN and E1_SERIAL_RX_PIN defined.
Rename them to Z2_SERIAL_TX_PIN and Z2_SERIAL_RX_PIN.

In "pins_RAMPS.h" file, find a block of a few lines that starts "E1_STEP_PIN", and rename E1 to Z2 for all those lines.

It may (or may not) work now. If it doesn't, please somehow post those configuration files.


Wrench drops temperature of heater block when tightening nozzle I've noticed when heating up the hotend to maximum operating temperature to tighten the nozzle against the heat break, after putting a wrench on the heater block, the temperature of the heater block drops by as much as 60 °C.  Do you ignore this or have a procedure to correct?

Mitigating "heat loss"
Technically, we don't lose heat, we have a drain of thermal energy out of the parts, but let's stay simple.
To combat the loss into the holding/steadying wrench, I use a vise: it might lessen the heating curve by the added thermal mass if used bare, but by adding two pieces of wood on either side of the heater block, I can insulate the block against the thermal drop from the steadying vise and atop that prevent scratches.
If you use an adjustable wrench for the heater block, one can add wooden "soft jaws" with a little cyanoacrylate glue, otherwise, some painter's tape or Kapton might aid.
It might help that my small wrenches have a super sturdy surface coating making them rather comfortable to use when left out in the cold and prevents rust. This layer also seems to prevent the flow of thermal energy into the wrench. Note that they are not chrome-plated but more like an enamel-look, a glassy powder-coat or actually lacquered.
Conclusion
When I need to mount something installed on the printer, I do the tightening as quickly as possible - the temperature of the measurement point and the temperature of the nozzle getting pressed into the heartbreak do not drop in the same instance, the nozzle will still be at the aimed for temperature when the thermosensor already has dropped.


Boolean operation on two objects in Blender I'm trying to draw a strange cup, with a kind of empty handle (actually, it's not a cup, but it looks like one).

I need to print this object with a 3D printer, so I exported the model to 3D printing software (Simplify3D) to obtain relative G-code for the printer.

I can correctly export (in .stl) both parts separately (cup [a] and handle [b]), and obtain a good G-code. But when I try to match the two parts with a boolean operation, the result becomes chaotic.

I've added a (G-code) picture to show how the slicer creates strange triangles inside the cup; I really can't understand how to prevent it.

I'm designing the print using the Blender 3D software modelling tool.

I've uploaded my file for reference.

The file has the bezier curves from witch I do screws in the origin. the result that I'm trying to export in stl is on the side.
Note: to have correct dimensions, I scale the model after 90° rotation on x-axis (base on bottom for printing), I then change the scale to 1:10 (bigger model), before exporting as stl.

I would obtain a sort of vase with an empty handle (the cylinder should work as an hole).

here what I do:

I convert curves to meshes
I screw the cup (360° y-axis)
I screw the handle (60° after rotation -30° on y-axis)
I solidify the handle
I add 2 operations to cup, (a) solidify, (b) boolean
to match the two solid I adjust the solidify (a) looking to boolean result of an intersection (cup to handle).
when I have the right overlapping I apply (a) solidify and then (b) union-boolean (cup to handle).
at the end I apply a difference-boolean modificator to cup/handle with cone, to create the hole.

I hope someone should explain me what I am doing wrong. I have made a somewhat simpler version here.

Check your settings in the slicer software you use: if you look at the sliced print carefully, you see only one line in each layer that crosses the inner section. The lines are also yellow, not green. This strongly hints that these are movement commands, not actual print commands.

On the other hand, you might want to carefully check in blender: at times, the normals in places get swapped inside out and then mess up the whole geometry without being visible in blender. Recalculate Normals can fix that at times, other times choose the messed up vertices and flip normals.

Make sure not to include voids in the model.

The model in question

Looking at the model, I also spotted that there was a lingering solidify modifier. Applying that resulted in this:

This is a particularly bad thing. Fixing is easy though: remove the offending inner vertices.

Atop that, the center points are a clustered mess of vertices - surely you want to merge them into just two vertices.

Applying the Boolean modifier now created a solid shell.

Before exporting, all other items had to be removed (deleted), then the export gives this nice model:


Extreme under extrusion Ender 3 Pro I'm having some severe under extrusion and I cannot figure out what's going on I replaced the extruder with the all metal one I've also replaced all the Bowen fittings and the tube with Capricorn tubing replaced the nozzle made sure everything was butted up tight can't figure out what's going on at all can someone please help I've only had the printer for 4 months and I've never had a problem like this before

I had a similar problem to you with my Ender-3 but now it is fine.
There are so many causes of under-extrusion that I doubt I can tell you what is specifically wrong in your case but perhaps I can give you some pointers.
In addition to what you have done, check if you can manually extrude the filament by releasing the grip on the filament (depress the lever on the feeder mechanism) and push the filament through with your hand (while the nozzle is heated to the correct temperature for your filament).
If that works well without too much force then it suggests one of two things:

an issue with the feeder mechanism (e.g. worn or clogged up teeth on cogs, spring too tight or too weak) or
extrusion settings on your slicer need modification (e.g. your slicer made G-code with too frequent retractions and this causes the filament to wear down thin preventing the extruder feeder cogs from gripping it. A solution is to reduce the maximum number of retractions possible by altering your slicer settings - this was an important factor for getting my machine to work again).
I found the following YouTube video helpful in giving me pointer of where to start - perhaps it will help you too:


Is B-REP a ready to print mesh before a mesh can be printed it needs to be 'repaired'. According to most tutorials that is including making the shape close and removing inner shapes. Reading through B-REP in Wikipedia there is no layman term or explanation how it differs form the traditional polygonal mesh create for example from scanning or exporting from CAD. Is B-REP a mesh that only represents a boundary and therefore ready to be printed?

a) about

  Is B-REP a mesh that only represents a boundary [..] ?

B-Rep contains more information, see here:

  There are two types of information in a B-rep: topological and
  geometric. Topological information provide the relationships among
  vertices, edges and faces similar to that used in a wireframe model.
  In addition to connectivity, topological information also include
  orientation of edges and faces. Geometric information are usually
  equations of the edges and faces.

b) about

  and therefore ready to be printed

it is need not only check that the model is correct (no lack of a face, no wrong face normals, ...) but also that is valid for a 3d printer (no "floating" parts, addition of supports, ...).

Finally, recall the model is not what drives the printer, the printer is controlled by the machine instructions, usually gcode. Thus, the usual evolution is: parts description (.scad, ...), model format (.stl, ...) and machine instructions (.gcode).


Brief very slow moves near top layers I've been trying to change to the latest Cura (v2.4) from the older v15.04 (I'm sure there's a good story about why they reset the numbers).

There's an annoying behaviour in my prints now, and I can't track down what is happening.  Everything goes fine, but during the print (maybe mostly near later layers) there are these moments when the print head doesn't move with the normal 30-50 mm/second, but perhaps 1-2 mm/second.

Watching the filament closely, it appears to retract filament at that moment, then the head moves painfully slowly around the part. Then 10 seconds later it goes flying around again.

Can't see a "print speed during retraction" setting. I see a speed at which the filament is retracted setting - I'm guessing that's unrelated.

I'm worried these frequent slow move sections are having two effects:

The hot print nozzle sitting on the part is deforming the surface features;
The hot print head is overheating the filament feeding into the nozzle and I get jams or sometimes swollen filament that won't go back into the nozzle as it tries to proceed further, causing a jam.

Any idea what makes these super slow movements? The older Cura never caused any of them.

I'm using a Monoprice Select mini printer, with six months of good results before this showed up, and only with G-codes created with new Cura 2.4.

Are the layers where this is happening smaller than previous layers? Many slicers have a minimum layer time setting where if the layer takes less than X time, it will either slow the layer down or possibly pause until the time is reached.

This can be useful to allow the previous layer to cool down and harden up a bit before more hot plastic is added.  If you're not having issues cooling the print then you could disable this.  I've only ever used Slic3r, KISSlicer, and Simplify3D so I'm not sure where the setting would be in Cura but those slicers all had/have the option.


How can I print a 1 cm overhang with minimal supports? Here's the thing I want to print.

The red ring is 3.5 mm above the bottom of the orange cylinder. The red ring is 1cm thick. I'd prefer not to use supports because I tend to break as much as I clean up.

I know this could be done in two pieces but then I'd have to make sure the pieces fit and then glue it in at that's too much. It'd be ideal to print this as one piece. How can I do this with as few supports as possible?

Three ideas

If either side of the red ring can have a chamfer to meet the cylinder, add the chamfer and print with the chamfer side down.
If both sides of the red ring must be perpendicular to the axis of
the cylinder, can you print the cylinder lying on its side?  You
might get good enough print quality, especially if printing with
thinner layers toward the top.
If that is unsatisfactory, try explicitly adding an inner support
ring as part of the model. Don't depend on the slicer to do what
you want, do it yourself.  You would then be bridging to make the
red disk, but that can work surprisingly well with a good cooling
fan and printer.

In all three cases, consider the slot holes you have in the red ring.  For case 3 you may need to add a support around those holes as well.  In case 2, they would want to be pointed vertically.  In case 1, the chamfer would be modified to have holes of cavities matching the slot holes.


Does anyone know how Slic3r determines its infill adjacent strand spacing, instead of using fill density? I'm doing research on changing the fill density into the air gap width, adjacent strand spacing, or whatever, instead of using the fill density, as it will give me more precise controls.

Question 1:

All I can work out is from Slic3r's the source code in ~/Slic3r/xs/src/libslic3r/Flow.cpp,

Link to Flow.cpp source code

/* This method returns the centerline spacing between an extrusion using this
   flow and another one using another flow.
   this->spacing(other) shall return the same value as other.spacing(*this) */

float Flow::spacing(const Flow &other) const {
   assert(this->height == other.height);
   assert(this->bridge == other.bridge);

   if (this->bridge) {
      return this->width/2 + other.width/2 + BRIDGE_EXTRA_SPACING; //Line A
   }
   return this->spacing()/2 + other.spacing()/2;                   //Line B
}

If I am right, will changing Line A or Line B, be the right way to change its infill adjacent strand spacing?

Question 2:

And since we're on this topic, what does the bridge variable represent?

This answer should have been a comment, except I have included the relevant code.

To answer question 2, at a guess, bridge is simply a boolean (bool) that specifies whether there is a bridge or not.

From Flow.hpp line 32

/// Represents material flow; provides methods to predict material spacing.
class Flow
{
    public:
    float width, height, nozzle_diameter;
    bool bridge;

    Flow(float _w, float _h, float _nd, bool _bridge = false)
        : width(_w), height(_h), nozzle_diameter(_nd), bridge(_bridge) {};

Additionally lines 68-73, may also be of interest:

    private:
    static float _bridge_width(float nozzle_diameter, float bridge_flow_ratio);
    /// Calculate a relatively sane extrusion width, based on height and nozzle diameter.
    /// Algorithm used does not play nice with layer heights < 0.1mm.
    static float _auto_width(FlowRole role, float nozzle_diameter, float height);
    static float _width_from_spacing(float spacing, float nozzle_diameter, float height, bool bridge);

However, your best bet, to get an accurate answer to both of your questions, is to contact Alessandro Ranellucci - alexrj, and ask him - as he is is the designer of the Slic3r code. When you get a reply, maybe you would like to post the answer here... it may be useful for someone else.


How to unclog a clogged extruder? I have a Wanhao Duplicator i3 v2 (A.K.A. Maker Select, Cocoon Create).

My extruder got clogged: I noticed that it wasn't extruding, so I stopped my print, removed the fan, heatsink and the extruder motor and I saw that the clog is at the heater block level.

This is a what I have:

As you can see, there is some PLA clogged at the very beginning of the 1.75mm hole in the extruder block.

I can see there is something white inside (a stone? something that is not PLA?). I tried to heat up the extruder to 250°C and pushing with an hex tool but the block did not move.

I solved a lot of clogged nozzle issues with the cold pull method, it always worked like a charm, this time I tried too but as a result the PLA filament broke and the "stone" is still there.

Does anyone know if there is a way to unclog the extruder in this situation?

Do I have to change it?

I'm sure this is not the best solution, and if you have some ethyl acetate you should try that before going "the hard way".

Ethyl acetate is a solvent for PLA, so if you soak the extruder into it PLA should melt and free the extruder.

That said, this is the "hard" solution that worked for me.

You'll need:

A drill
A 1mm drill bit
A 1.5mm drill bit

Insert the 1mm drill bit into the drill. If your drill has a setting to reduce the drilling speed, take this to the minimum speed. If your drill doesn't have such options, you'll need to push the drill button very gently.

Put the drill bit on the pla block (be sure to not touch the cooling block, you might ruin it). Start drilling at the minimum speed and push very gently, until you get a side-to-side hole on the PLA (you know it because you feel no resistance at all while pushing the drill).

Take the 1.5mm drill bit and repeat the same operation. At this point my PLA block literally exploded (now I have some broken PLA inside my room, don't know where) and the extruder was finally free.

I hope this helps someone. Please notice that you need to be very gentle in order to avoid breaking parts of your extruder, but if I managed to do it, you can do it too ;)

As previously said, if you have ethyl acetate try soaking the extruder into it to make PLA dissolve before trying this. Try this solution only if all other options didn't help.


What type filament should I use to produce stamps? My wife wants me to use an FFM 3d printer to make custom stamps for her to use on paper (scrap books, letters, etc.). She is convinced, however, that they will be too rigid to make good stamps.  A quick google search showed ones made from PLA and ABS. Logically, though, a TPU or similar would address her concerns.  A good quality stamp needs to hold ink and make good, even contact with the paper. It would probably need to be able to be sanded or smoothed in some way.

I am supposed to receive my printer next week or so and am trying to get some filaments, STL files, and accessories I will need ready in advance so I can rapidly learn how to use it.

I see three options...

1. Print with a flexible filament:

Many options: TPU as you pointed out, the flexible PLA that Tom mentioned, and others.  Here's an article with a few options from Matter Hackers
I'd suggest printing the stamp side down so you get a nice flat stamp with no post processing.  For any wide gaps, mind your bridging...use fillets or chamfers so the "roof" of the gap is an upside down V or U shape.

2. Print with any hard filament, but use a rubber mat under the paper.

The idea here is to use a semi-flexible surface under the paper to help get uniform contact pressure between the paper and the hard stamp.  As long as your stamp holds ink, this should work okay.

3. Print your stamp shape, then use it to make a rubber stamp.

Making a model and then copying it with your desired non-printable material is a common manufacturing technique that can be used in many situations.  Use of molds for casting and related processes can really expand your possibilities.  Check out Smooth On.  They have several rubber and flexible compounds that you could use for stamps.


What filaments allow air to pass but not water vapor? In some situations it useful to have a material in which air passes but water, and water vapor, does not. Printing cell membranes or cases for something that must be immune to humidity changes (like something that holds a highly oxidative metal) are two examples.

Teflon (PTFE) is a material that has this property. But PTFE is horrendous to 3D print.

Silicone is another material that has this property. 3D printing silicone can be done with a syringe mechanism. But there are also thermoplastic rubbers (e.g. TPU, TPE) that are designed to mimic Silicone.

Are there any filaments on the market which naturally form holes with the porous diameter for this feature? Is there any way to manipulate the diameter of this hole, even starting from pellets? Are some filaments more likely than others to have this feature?

It is difficult enough to make 3D-printed objects water-tight (unless you paint them). Making them permeable to air but not water vapour is too big an ask, I think.


Does the Da Vinci line of 3D printers come with a heated bed? I'm now currently looking at getting my next 3D printer, after my success with the Prusa i3 Reprap Build, and I have had my eyes on the Da Vinci line of printers for some time now.

What I want to know is, does this line of 3D printers include a heated bed? Or does it come with a stock aluminum bed?

Yes. The Da Vinci Duo 2 (most common one) has a heated bed.


Sparkmaker SLA resin not curing My model layers are printing much as I expect but the parts when removed from the plate are very soft and flexible and fail to harden any further in sunlight or UV lamplight.  A tall or slender part will bend and distort under its own weight while printing.  I am using LCD-T resin, I have increased time and reduced thicknesses and am now using 0.04 mm layers at 20 s and 255 brightness with no improvement.
Can anyone suggest what I need to change?

It might be the case that the resin separated into layers in the tray. Try mixing the resin well in its container.

I have also heard it can help to filter the resin prior to mixing.


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.

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.


Writing G-code: Audible Alert at end of print Often, the pre-generated G-code is enough for start and end. However, sometimes we want to have something different. In this case: how to generate an audible alert of something like 4 bleeps at the end of the print, after putting the printer into the end position and when the bed has reached a "safe" 30 °C?


Heatercartridge bolt stuck After a brownout a print failed and it got the whole hotend covered in PLA. I am now in the process of replacing some parts on the hotend (one of the thermistor legs broke of) and also wanted to take the heater cartridge out. The problem is that the bolt that locks the heater cartridge is stuck and I am now afraid to strip the head.

Is there a trick to remove the bolt with the smallest probability of stripping the head? Is it better to apply heat or not? Should I soak it in Acetone or some other solvent? etc.

Don't Panic!
First of all, a printhead caked in PLA is usually not a death sentence, it is often a temporary setback. Let's start in steps!
Step 1: remove the extruder
We want to work on the hotend, so we remove the extruder feed first. For direct drive, we unload it, then remove it depending on your printer, so the cooling of the hotend remains. For a Bowden, unload and, if possible, remove the Bowden tube from the cooling block. If not disconnect it from the extruder.
Step 2: remove from the carriage
Now that we have the whole hotend assembly bared, we remove it from the carriage. Usually, it is 2 to 3 bolts, more if the cooling solution is mounted separately and has to be removed to access it.
Step 3: remove the cool-end
If you can, remove the cooling fins - we want to have the heatbreak to hold on to.
Step 4: Clamp it up
Take a fire-proof surface (ceramic tile!) and put down the hotend. Rig it up that it can't jump away, best with a small vise. Don't bend the cables!
Step 5: Free the thermosensor
Let's start to clean! If your cartridge still works, get 12V onto the heater and let the stuff melt a little. Use pliers and a scraping tool to clean the thermistor cartridge.
As you have no heat control only heat in short bursts to prevent fire and destroying the cartridge too.
As an alternative and if you can't get the cartridge to work, use a hot air gun or a hot-air soldering station. A soldering iron with a broad tip also works well to scrape off the plastic with controlled heat an as a scraper to remove large chunks.
If you use an external heat source, free the heater cartridge first and remove it, hoping that it is not also dead.
As soon as you can, get the thermosensor out. If you run on the heater cartridge,  install a fresh Thermosensor, even into the goopy heater block, and wire it to the board to regain temperature control and use the board to provide the power.
Step 6: Finish cleaning
I usually clean up the final stretch (and as far as I can: all steps) under board controlled heat:
Make sure that heater cartridge and thermosensor are installed well and working. Set the hotend to 170 to 180°C and do the last cleaning under the use of regulated temperatre.
Step 7: Do steps 1 to 4 in reverse order.
Reassemble, following the steps backwards.
Step 8: Hot Tighten!
Heat the assembled hotend to 240°C, then tighten the nozzle against the heatbreak to ensure tightness. Let cool, done.
Alternative
Replacement/Upgrade!
One could go down to step 3 and replace the hotend assembly (Heaterblock, Thermosensor, heatbreak, nozzle) with fresh parts and reassemble. This is much more expensive than reusing but cleaner and faster - if you need to print now, you might want to keep one hotend assembly on hand as spare and clean the one replaced while the machine runs.
External heat sources
As mentioned, a hot air gun or soldering iron can provide heat to remove the plastic caking.
The soldering iron has the benefit of doubling as a scraping tool and providing localized heat, allowing to possibly free the thermosensor without unsoldering anything in it, and it won't melt the heater block.
A heat gun provides gentle, overall heating of the beater block, but needs extra care where the hot air is going - it can easily char wood and might remove the solder from the heater cartridge.
A gas torch might be used to burn off any residue on a totally stripped heater block, but it also would be able to melt and deform an aluminium heater block! Do not use it on a still assembled heater block, or it will melt any solder in the heater cartridge and destroy it.
In any case, working on a fireproof surface is mandatory!
Chemically cleaning (for non-PLA)
PLA can be removed chemically, but the solvents are rather nasty and some take quite some time to work. Very toxic dichloromethane was used to make a solution of PLA to create thin layers used in this paper, and most other solvents the study mentions are at least equally nasty. The available working options - ethyl acetate and propylene carbonate - have high price tags associated with them. So chemically cleaning PLA from cheap nozzles is not an economically viable option. However, it is a viable option to use acetone if you have your hotend caked in ABS.


How can I make bed leveling improvements in the middle of my Ender 3 V2 bed? Got my Ender 3 v2 and stack with the bed leveling.
Used default settings, Creality slicer 4.2, test PLA from the kit and print model https://www.thingiverse.com/thing:3013319 (4 squares in each corner and 1 in the middle), nozzle 200 °C, bed 60 °C.
After some adjustments, I have good solid pieces on the bed corners  but the center one has small gaps. Is it possible to fix this problem?
Corner pice:

Center piece:

The gaps are, because the nozzle is to far from the bed at this point. It may sound like a big deal, but actually this is not leveling alone, but it looks like the bed is not a perfect plane/perfectly flat. This is normal, my ikea mirror and my stock bed show the same thing. Now here's one solution:
Print calibration stickers, like you already did on various places around the bed to get a feel, where it is too low. Let it cool and put painters tape (the very very thin tape, that should not burn) on areas, where the bed is too low. Print more calibration rectangles and check if you have enough. Repeat until you cannot see a difference.
It took me about 2h to level everything absolutely perfectly. This was 2 years ago and I didn't have to touch the tape below my bed ever since. It just works.
Alternative solutions involve mesh bed leveling and buying a new bed surface or even the surface below the bed. However, I found that to neither of them work reliably, whereas the simple tuning does what it's supposed to.


Using both .gcode and .gbr files in a hybrid 3D printer + circuit etching machine? (RepRap 1.4 with Marlin firmware) I'm making a hybrid 3D printer and circuit etching (CNC milling) machine that can both 3D print and etch prototype circuit boards. I'll be using Marlin firmware with an Arduino Mega & RepRap 1.4 board. It will have a 3D printer head and a milling head side by side. I'd like to have it be able to read both .gbr (for circuit etching) and .gcode (for 3D printing) files. How should I configure Marlin to read both types?

You can use both .gcode and .gbr files one one machine. We do it where I work.

However, when we make prototype circuit boards, we don't print them; we acquire circuit board blanks, and then we either:

Use a diode laser to burn off the top layer of garolite for isolation traces, then do a chemical dip to remove that copper, then another laser burn to expose pads for surface mount components; or
Use a spindle tool to remove the top layer of garolite where needed for pads, as well as mill through the copper layer for isolation traces.

We have not found a printable material that has the conductivity we want in a circuit board.

Source: I work for Hyrel 3D

Note: we don't use Marlin on Arduino, we use in-house firmware on STM32F429 boards.


Slic3r not interpreting STL correctly I'm very new to 3D printing, I purchased a Monoprice Maker Select Plus last week and I'm just getting started with printing my own models.

I can create fairly simple models in Sketchup without a problem, export in .obj, then using Slic3r, covert the STL into G-code. This method worked fairly well for some simple cubic bearing holders I was printing, however when I tried to slice a complex shape (a wheel), the slicer shows an incomplete version of the .obj file, missing faces and transparent from some angles.

Here is now what the wheel looked like on the slicer

There is obviously something I'm doing wrong in Sketchup, maybe I have to put it through some filters in MeshLab? Or I'm not constructing the model properly?

Sketchup is notorious for creating non-manifold models for 3D printing. The first recommendation would be to consider using a different resource for your models. I'm not a big fan of TinkerCAD, but it is similar in operation to many features of Sketchup. I've used it on a couple occasions where it was the fastest simplest way to create a particular model.

There are other programs that are more complex in the learning curve. Meshmixer is good for more organic shapes, although it will perform reasonably well for engineering-type models such as yours.

Blender is a great piece of free software with an extremely steep learning curve, but again, better suited to organics.

I'm quite a fan of OpenSCAD which is script/text based and quite well suited to creating engineering-type models, especially if you need parametric modeling. The model you have in your pictures would be an easy build, perhaps twenty minutes creation time, a few dozen lines of text. I see two cylinders, some boolean subtraction and some radial primitives. If the code is clean (easy to do), the result is a manifold object.

On the even more challenging level, there are programs such as SolidWorks but the learning curve there is steep too. In the same ballpark would be Autodesk Fusion 360, for which a free hobbyist version exists.

Of course, with all of the above, there are YouTube tutorials to assist your learning process.

More to the point, one can use an online 3D model repair service. I've attempted to use a couple with mixed results.

Netfabb is a commonly recommended online repair service. I've not used that one, or if I have, the results were poor. A bad model (your example) will likely fail with most services.

I've used MakePrintable in the past as well. Again, a bad model will fail and Sketchup is the culprit here.

You can use Meshmixer in Analysis mode to find the errors and use Auto Repair All, but the results aren't going to be pretty!


Moving Extruder Gear Assembly So I am getting a Creality CR-10S which has a similar print frame with a lot of other printers. Eventually I'm sure I will want to print using flexible materials, but the bowden system is not optimal since you're basically trying to push cooked spaghetti through a tube. I could replace the bowden with a direct drive but that can be expensive (and potentially shave off 15 mm from one of my axes). Not to mention that the print head is now heavier which can affect print speeds and quality.

That's when I thought about moving the extruder gear and motor from the side of my printer to the top. The tube then goes down the Z axis so the flexible filaments are pulled by gravity and controlled by the gear instead of just being pushed by the gear. (Please refer to my wonderful sketch)

I can't be the only one to think of this, but I've only seen one website that has talked about this issue and thinks that the solution is a second gantry to follow the hot end. If you're interested, here's the link.

Are there any potential issues with this new setup? Though I would mount the servo above the cross beam instead of to the side so that there's full range of motion along the z axis. (sadly that thought came to me AFTER making the picture in paint)

Hanging up the Bowden system won't fix the problems with printing flexible filament: the filament will still press into the bends of the tube and thus lead to under extrusion. Another issue is, that the flexible filament can compress - and the longer way it has to the melt-zone, the more filament it can "store" on the way to it. These bunched up zones will release suddenly, resulting in pulses of high output and between those under extrusion.

Direct drive (like in a Prusa i3) is pretty much the only way to reliably print flexible materials. You could, with some engineering, move your existing motor to the carriage and turn your Bowden into a direct drive.


3D scanner data acquisition I found an old Creaform3D EXAscan laying around at the company I work for, and tried to plug it on a computer to see if it still works.

I discovered that it uses a software called RapidForm for data acquisition, but its license is expired.

I looked in the manufacturer site for drivers or something similar but there isn't anything.

Is there any other software or way to read the data coming from such scanner?

The Creaform EXAscan is according to the manufacturer a laser based machine. This means that it determines data points and their positions by some triangonometry done with a laser, 32.000 times a second, resulting in very high density point clouds. This demands a powerful program to work with.

At some point, your company used Rapidform, which costs a wooping 10 to 30 grand for a license. Other software in this niece are - according to a solidworks thread - Geomagic and PolyWorks. The gist of the thread seems to be that these "big 3" were the best ones at the market in 2011. However I have no idea if they work together with the given hardware or what the later two cost.


Does PETG fade in the sun? I'm looking at scanning in a statue on my pond and making a print of it. I'm wondering if PETG will fade and how fast. I'm thinking of using white or maybe a bone color if possible.

If PETG fades kinda fast, what material should I use? Keep in mind this will deal with all weather types, full sun, and it will have water coming out of it.

I've been 3D printing for a bit, but I never made anything to stay outside for looks. I know PETG is pretty good at water, and I think it's stronger than ABS when it comes to weather. But I'm in NC, and I even lived in FL at a point. Shockingly, I found the sound in NC can bleach wood in a matter of days to weeks in the mid of summer where it might take all summer in FL. So I'm worried what I might make will get that yellow fade look that plastic does in the sun.

tl dr: For the most part, yes it should be color fast in the sun. It should be good for outdoor use.

This website claims the following:

  Filament materials ... for outdoor use include ASA and PETG that are perfect for use in extreme conditions without changing shape or appearance. Printed pieces do not change colour either with the sun's UV rays and do not take on a yellowish appearance as does ABS, for example.

Please realize, this is partially an advertisement (and no, I have no affiliation). What it boils down to is, PETG and ASA are going to be better for outdoor use, but every brand of each is going to be a little different in how well it reacts to the elements. Without advertising on the site, you'd need to do a little investigating on your own, with the possibility of testing different brands to come up with what you believe is the best. Beyond that, it's just an opinion.

I doubt any filament, no matter what it is made of, is going to be perfectly colorfast in the sun. The sun is a harsh beast. It will bleach a printed object over time. Some colors are going to be more susceptible than others, especially red. This is due to the color of the sun. Again, some filaments are going to be better than others, but I'd not expect any filament to be perfect.


E3D V6 underextruding always? I have an E3D v6 1.75mm bowden.

When I print, there is a gap between infill lines, and also when printing rectilinear/hexagonal infill lines seem to be pretty slim.

My settings:

Slicer: Slic3r
Nozzle size: 0.4mm
Print speed: 30mm/s
First layer print speed: 15mm/s
Travel speed: 90mm/s
Retraction length: 0.8mm
Retraction speed: 40mm/s
Extrude ratio: 1 (tried also with 0.48mm extrusion width, I remember it's the default S3D setting, so I gave it a try)
Print temperature: 220 °C
Material: PLA

Firmware settings:

Firmware: Marlin 1.1.0-1
Motion system: CoreXY
Acceleration: 1000
VMax X: 300
VMax Y: 300
VMax Z: 5
VMax E: 80
Xsteps/mm: 80.05
Ysteps/mm: 80.05
Zsteps/mm: 400
Esteps/mm: 96.5

Disclaimer: I set Esteps/mm to 96.5 because I calibrated the printer as described here, so I'm 100% sure it's an accurate setting. Same for X,Y,Z steps. I printed a cube and calculated the real steps per millimeter, and it's accurate too. The extruder motor works, it's not the issue.

Here you can find some pictures that show what I'm trying to describe:

While printing I tried to release the extruder motor clamp and push the filament by hand: it extruded 1mm thick lines, so the extruder is not clogged and is perfectly capable of extruding the required amount of PLA.

Is it possible that the VMax E parameter is preventing the extruder motor to extrude properly? I mean, could it be that it's trying to extrude at a higher speed than the maximum allowed? Seems weird to me, because comments in Marlin's Configuration.h file say Default Max Feed Rate (mm/s) for that parameter, so if the limit is set to 80mm/s it should extrude just fine. If this is the issue, how should I solve it?

Major factors affecting extrusion:

Nozzle diameter
Extrusion ratio
Extrusion stepper calibration
Filament actual diameter
Extrusion width setting
Nozzle temperature

According to the photos, temperature is acceptable (may be a bit high, but it is not a problem in this case). Extrusion ratio is 1 and should not be changed in normal operation. Extrusion width is often set to auto but sometimes calibrating it gives better results in slic3r. If stepper is calibrated properly, then I would check for nozzle and filament diameters. For nozzle it should be enough to verify that 0.4 bit fits in and 0.5 doesn't. Filament can be measured by digital caliper. Difference between 1.75 and 1.73mm may have significant difference resulting in under-extrusion.


Top surface scarring even with Z hop When the print is finished, it looks like the extruder is digging into the top layer as it returns to home?

I tried adding Z hop at 5 mm but it's not really helping.

Sorry for the picture, white on white is hard to show.

I tried a range of speeds from 40-90 mm/s and over extrusion of 100-105 %, but the scar remains.

Any suggestions?

Here is the end code:

;TIME_ELAPSED:333.340017
G1 F1500 E417.35346
M140 S0
M141 S0
M107
M104 S0
M140 S0
;Retract the filament
G92 E1
G1 E-1 F300
G28 X0 Y0
M84
M82 ;absolute extrusion mode
M104 S0

Z-Hops only occur when the slicer is retracting Filament automatically (i.e. when Cura detects a move between parts/around outer walls where stringing would be a problem).

In your end G-Code, you do retract your filament, but manually. This means that Cura does not add the Z-Hop code.

Solution:
Add this before your G28 X0 Y0 command:

G91   ;Change Positioning to relative
G1 Z5 ;Move head up by 5mm (or bed down, depending on your machine)

The G91 command is needed because otherwise you wold need to provide an absolute Z position which is guaranteed to be above your last layer (so you would either need to set the height to the top of your build volume (takes ages to move the head there) or to adjust the height for each printed part (annoying)).

Documentation for the G91 command: http://marlinfw.org/docs/gcode/G091.html

Manual for Z-Hop and other travel moves in Cura: https://ultimaker.com/en/resources/52507-travel

Edit:

Note that this is only a good idea if MAX_SOFTWARE_ENDSTOPS are enabled in your Marlin configuration.h. Otherwise, the head could move ABOVE the maximum Z height (zMax) if the print height h >= zMax -5mm.

Thanks to @0scar for mentioning this!


How to create attachable/detachable printed parts I am making a part that needs to come apart, so I don't want to use glue or similar adhesives. I saw an article about printing snap-fit pieces, but it seems like you would need a lot of expertise to make it work well. Does anybody know of an easy way to non-permanently attach PLA parts, while still maintaining a sturdy connection?

EDIT: (more detail about specific project)
I need to attach plastic to plastic, in a pretty small surface area. This is a prop knife/sword in which the "blade" retracts into the handle.  For the prototype I printed the handle in two halves lengthwise, which I do not want to do for the final product. I want to print as much of the handle in one piece as possible. Because I need to get the blade into the handle (and remove it for working on parts, painting, etc) I need part of the handle to detach. I am thinking that the front bit (examined more closely below) would be the best place to detach.  As the wall thickness is about 1/4 in, there is not a whole lot of room to work with. However, I remain hopeful that there is a way to attach it such that it will remain securely together and retain the "blade" properly.

Thanks for the help so far.

This question may yet fall into the too-broad category, but I'll give it a shot.

You don't want to use glue or adhesives, but does that exclude bolted or screwed fasteners? Threaded inserts are metal "nuts" with knurled grip extrusions that enable one to use a matching bolt. The insert is heated with a soldering iron or similar source and embedded into the part. It's especially useful when the part thickness provides sufficient strength and the threaded insert is on the surface of the part opposite the bolt head.

Another option you have is to design into the part a "conventional" joint such as a dovetail or slot with the matching dovetail or T shape on the adjoining part. This requires access to the end of the part to enable the sliding action of joining them together, of course. Some testing of prints should be performed to ensure proper mating.

Directly related to that method is pins and holes. With suitable testing, one would create a hole on both parts and print a pin to match. If one is well versed in the software of choice, one hole with a built-in pin on the adjoining part would work too.

Yet another extension is provided free from 3DKitbash:
http://www.3dkitbash.com/free3dmodels/
in the form of friction fit pins. I've constructed one of their models using this design and find the straight-line pins eventually work free. The pin model with "mouse ears" allows for a bit stronger gripping due to the compression of the shape on insertion.

The friction fit pins would be considered to be the snap-fit parts you want to avoid, but the level of expertise should not be beyond that of a model designer.

Trial and error works wonders when it comes to putting these things together. I printed an Overwatch logo for a fellow makerspace member. The part used a pin on the insert and a hole on the logo. I was astonished when the two different colored parts slid together quite snugly. I have not calibrated my printer and it was indeed a snap together build. On the flip side, when I pried the two pieces apart (low infill) the pin remained in the hole, snapping cleanly off the insert. Should I be asked to do this again, I would have much more infill on the pins.

For clarification, consider also to note what software you are using for your design. Some programs lend well to creating connections, others not so much.


Are there practical reasons to NOT use a stepper motor with lead screw for the X and or Y axes? After a few months of printing with my Prusa Mk3 (with plans to get a second one soon), I have been wondering about making my third printer a home-built one was a larger print bed than the Mk3. One thing I wondered about is perfectly expressed in the title question.

Are there practical reasons to not use a stepper motor with lead screw for the X and or Y axes?

I am certainly happy with the GT2 belts used in my current printer, but I wonder if the design might be simpler with lead-screws on all three axes.

I am going to answer this as someone who actually did rework their Prusa i3 fleabay clone to use leadscrews for all axes. Before digging into the matter, the backlash issue can be solved easily with spring-loaded brass nuts, kinda like how ballscrews work. That's the simplest problem to solve though as there are a lot of other issues.
Short version / tl;dr

Hardware can't handle that many microsteps.

Crosstalk and motor inductance limit speeds and acceleration.

Print quality suffers in really weird ways because of (2).

Leadscrews are not made for quick movement over extended periods of time and will wear, even with grease.

You'll need additional bearing surfaces to prevent your motors from grinding themselves apart, and to eliminate backlash due to the flex couplings.

The system becomes a lot more prone to highly destructive failure modes.

Long explanations
First
You're going to notice is that you're constrained to horribly, horribly slow movement and acceleration rates. My screws are 8 mm screws, with 8mm pitch. That means it takes 200 steps to travel 8 mm. Multiply by 1/16th microstepping, and that's 3200 microsteps per 8 millimeter of travel. Multiply by whatever speed you're trying to print at, then the number of axes you're using, and you'll find that your RAMPS board starts to stutter on complex moves if you print fast enough.
Second
You'll quickly hit the inductance limits of your motors. At "standard" power levels (ones that don't fry my knockoff NEMA17 motors), even after switching to 24 V for the entire setup, the fastest I could spin my motors was about 5 revolutions per second, which translates to 16,000 microsteps per second with 8mm pitch screws. For reference that means that under ZERO load, the fastest my N17 w/ 8 mm pitch could travel, is about 40 mm/s.
You're basically running the motor coils at several kilohertz, which means you have to be really careful about keeping your wires separate and shielded to prevent crosstalk, in addition to the fact that as your step frequency goes up, your step torque goes down dramatically. Not only does this limit the weight of the bed that the motor is capable of pushing at a given speed, but you even have to worry about the inertia of the motor and bed much more than with a belt-driven system. So instead of 30 mm/s jerk with 200 mm/s2 acceleration, suddenly you're limited to, say, 5 mm/s jerk and 40 mm/s2 acceleration.
As mentioned, for best results, the whole system needs to be converted to 24 V, and not all boards are configured for this to be easily done. My cheap RAMPS clone only needed a single diode removed and everything else was fine, but YMMV in this regard.
You could solve this particular problem by gearing the motors down, but at that point you've now introduced a new source of backlash either between the gear teeth or in the belt drive system, and kinda defeated the point.
Third
Due to this effect, is that you run into extrusion pressure artifacts. Basically, the plastic in the nozzle is a fluid, a very viscous one, being forced through a small hole. The fluid pressure will "lag" somewhat behind what the extruder motor thinks is happening.
The end result is that while you're accelerating, the lines you're laying are thinner than they should be, and will be thicker than they should be while decelerating, and you tend to get weird "globs" on each corner when you come to a stop. For me, with a 0.4 mm nozzle, 0.8 mm line width, and 0.2 mm layer height, these artifacts actually completely offset the additional accuracy I was getting with a tightly-coupled leadscrew with spring loaded dual nuts on it. The parts ended up being even less dimensionally accurate than before, with very strange deformities.
There ARE settings you can use in the firmware to try and combat this specific effect, but the process is tedious and takes a lot of trial-and-error, and recompiling the firmware every 30 seconds is annoying, not to mention the variables are dependent on line width, speed and acceleration settings, and layer height, so you have to recompile your firmware any time you want to change the print quality. Super, super annoying.
Fourth
Leadscrews aren't actually designed for this. The constant back-and-forth motion will wear the brass nuts and even the steel threads of the screws over time. You end up with a black powdery residue on everything underneath the screw, which, in the X axis, typically also means your print. Nobody wants steel powder messing up their layer adhesion.
In my case I used Superlube, which is a silicone/PTFE grease, to help prevent this problem, but that only works so well when you've got spring-loaded brass nuts. Eventually they push most of the lube out. Additionally, the lube tends to grab and hold any metal powder that does form, accelerating wear in areas that are still lubricated.
Fifth
Bearings. Turns out motors have internal bearings, that generally suck and aren't made for heavy loads in any direction. I found that out when my Y-axis N17 motor failed because the bearing did, and spread powder all over the coils, some of which got pushed through the enamel and shorted the wires out.
Additionally, because tiny amounts of misalignment turn motors into shrapnel in a hurry, you're almost certainly going to be using flex couplings. Flex couplings have a certain amount of yield to them axially, and are primarily designed to be under compression loads, and tend to fail when stretched repeatedly.
For the Z axis this is normally not an issue because the whole system is held down by gravity, but in the X and Y axes, you'll get some weird offsets of even a millimeter or two each time the carriage or bed switches directions. So you'll want to make sure that the motors aren't load bearing themselves, and the screw remains locked relative to the frame while still being able to rotate.
You can accomplish this by having a ring fastened to each end of the leadscrew that either pushes on a thrust bearing or rides in a regular ball bearing. Ideally, you can do both, but this turns into an expensive venture with a whole lot of brackets in odd places that you may not have space for. I ended up losing about 20 mm of bed travel solving this problem.
Sixth
You need to think about what happens when a component fails. For me, it was my endstops. The first failure was from the crosstalk issue I mentioned above. Y-stops triggered, bed started shifting towards the front of the printer over time, and eventually the printer started trying to move the bed through the front of the printer frame.
It was successful.
The second time was simply the endstop switch failing mechanically. Belt travel stops at the pulley. Leadscrews go all the way to the end of the screw, and because they're geared so much lower than belts are, there's a lot more torque involved. I destroyed my printer frame three separate times because of this problem, and once more when the Y-axis flex coupling snapped. This allowed the motor to spin the screw easily in one direction but not in another - which this time forced the print bed backwards instead of forwards, yanking the Y motor through its bracket and the frame again.
Conclusion
X/Y screws are not necessarily a bad idea, simply an expensive and tedious one in 3D printing. They're much better suited to low-feedrate applications like CNC mills, mechanical engravers, and the like. You may notice that even high-accuracy applications like laser printers tend to have belt-fed carriages rather than screw-driven ones. Screws are much better suited to high load, low-speed applications, and printers tend to be the opposite of that.
If you're trying to eliminate backlash due to the belts not being tight enough, as I was, the answer is to make a better printer. I couldn't tighten the belts enough to get my prints accurate before the motors started failing, because I didn't have the motor-end pulley supported by a bearing. Start there, literally just support on either side of the pulley on the motor shaft with a small bearing braced against the frame to take the radial load off the motor. If your belts are stretching too much, use steel-core GT2 belt. If your system is overall just sloppy, build a more robust system. My current project is a Hypercube Evo, and I found a supplier that makes steel-core GT2 belt. I'm going to use that to maximize rigidity in the CoreXY belt system. The frame is made from 30x30 mm T-slot extrusions, with 12 mm Z-axis rods and 10 mm X/Y axis rods. Bigger, more expensive components that are way more robust and will flex much less than the 400 mm long 8 mm rods on my cheapo printer.
Hope this helps.
(edited to get my math right on the microsteps)


Printing a part from two materials I am trying to print a large part from PolyPro but can't get it to stop warping when I remove it. It also doesn't stick well. I have tried playing with printing speeds, temps, extrusion % etc. Even tried putting packing tape on the bed (which helped it stick but didn't prevent the warping).

I thought I might try printing a base layer (2 mm) of PLA, the print the rest of the the part in PP right on top of it. The PLA hopefully will stick and keep the walls of the part straight. My question is how to do this. Is it as easy as cutting off the bottom 2 mm of the part and telling the design software that the part rests 2 mm above the bed, then tell Cura not to print a support?

You could just let it print the 2mm you want for the base, then pause the print and change the filament to PP and then resuming the print after you change the filament.


What is wrong with my "disable sensor" gcode? I have a spool of translucent PLA filament that doesn't work well with the filament sensor on my Prusa i3 MK3. The translucency trips up the sensor, making it think the filament ran out. I thought I'd create a filament profile in Slic3r and disable the sensor in the "Start G-code" block that gets inserted at the beginning of the exported gcode file.

I've got the following code:

M900 K{if printer_notes=~/.*PRINTER_HAS_BOWDEN.*/}200{else}30{endif}; Filament gcode
M406 ; Disable filament sensor
M117 Filament sensor OFF

The first line is provided by Prusa's default PLA profile. The second line should disable the sensor, and the third line should print the "Filament sensor OFF" message. If I look in the gcode, it's there:

G92 E0.0
M221 S95
M900 K30; Filament gcode
M406 ; Disable filament sensor
M117 Filament sensor OFF
G21 ; set units to millimeters
G90 ; use absolute coordinates
M83 ; use relative distances for extrusion
;BEFORE_LAYER_CHANGE

But if I print this gcode file, I see no message, and when checking the sensor in the "Tune" menu while printing, the sensor is still on.

I thought I might have a problem with line endings, but looking at the file in a hex editor, all the lines seem to end with a 0A line feed character, including mine.

Why isn't my printer doing anything with the M406 and M117 messages? Full gcode file here.

As per github PR this is not implemented - see this PR for details
Please check if your printer is processing M406 by issuing it manually.

In meantime, a sticker on the sensor will help you to print :)


What is the MakerBot Grip Surface lifespan? I've done a few prints on my MakerBot Replicator+ now and I'm curious if anyone else knows what the typical lifespan is signs of degradation are for the grip surface tape?

I'm used to using Kapton tape in the past. Which will bubble, scratch, and even tear at times, indicating that the tape should be replaced. However, this new MakerBot "Grip Tape" is a very stiff, precut material, with extruded plastic anchors to help evenly spread the tape and keep it secure on the build platform. The tape also has texturing on the top face that helps with adhesion.

So, this new tape seems somewhat impervious to bubbling, scratches, and tears. I'm curious what signs I can look out for that indicate that this new grip tape needs to be replaced.

Obviously the tape isn't a permanent solution, so what are some signs that the tape should be replaced?

There's no quantitative formula for the lifespan of any grip material, be it tape, glue, or PEI sheet.  If you find a lack of stiction and it's not due to small changes in the Z-origin (50 microns can make a big difference in the way the first layer grabs the bed!), then replace the tape.  It's cheap.

Just to be pedantic, torn and scarred tape should be replaced :-)