Filament Leaking During Automatic Bed Leveling Before the print has actually started I have set up Auto Bed Leveling using a BLTouch sensor, during the period that this runs I find that material leaks out of the nozzle and curls back onto itself and by the time it finishes it is substantial enough to cause problems when the nozzle is primed  drawing the line to the left of the print. The material that leaks out catches on the material extruded to prime the nozzle, before printing the model so when the first line of the model are extruded to very quickly pulls up off the bed and becomes a massive tangle of material.

I try to catch it my self using various thin instruments to scrape it off the nozzle as it starts the priming but this isn't always successful and is far from ideal. I have also tried adding a retraction before the bed levelling starts suing the gcode commands added to the beginning of every print, at the moment however I find that a retraction large enough to stop the leaking material also means that material doesn't come out for the priming in time so the first lines of the print don't work.

The gcode at the beginning of the print is as follows:

; Ender 3 Custom Start G-code
M104 S{material_print_temperature_layer_0} ; Set Extruder temperature
M140 S{material_bed_temperature_layer_0} ; Set Heat Bed temperature
M190 S{material_bed_temperature_layer_0} ; Wait for Heat Bed temperature
M109 S{material_print_temperature_layer_0} ; Wait for Extruder temperature
G28 ; Home all axes
G1 F1800 E-3 ; Retract filament 3 mm to prevent oozing
G29 ; BLTOUCH Mesh Generation
G92 E0 ; Reset Extruder
G1 Z5.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
G1 X0.1 Y20 Z0.3 F5000.0 ; Move to start position
G1 X0.1 Y200.0 Z0.3 F1500.0 E15 ; Draw the first line
G1 X0.4 Y200.0 Z0.3 F5000.0 ; Move to side a little
G1 X0.4 Y20 Z0.3 F1500.0 E30 ; Draw the second line
G92 E0 ; Reset Extruder
G1 Z5.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed

I am using an Ender 3 running Marlin 1.1.9 with BlTouch Auto Leveling, With slicing done by CURA 3.5.6

Any suggestions you have that would help to stop this would be greatly appreciated.

The oozing is due to hot-end getting hot before the bed leveling procedure: if you move the hot-end warm up command after the G29 line you avoid that oozing

; Ender 3 Custom Start G-code
M104 S{material_print_temperature_layer_0} ; Set Extruder temperature
M140 S{material_bed_temperature_layer_0} ; Set Heat Bed temperature
G28 ; Home all axes
G29 ; BLTOUCH Mesh Generation
M190 S{material_bed_temperature_layer_0} ; Wait for Heat Bed temperature
M109 S{material_print_temperature_layer_0} ; Wait for Extruder temperature
G1 F1800 E-3 ; Retract filament 3 mm to prevent oozing
G92 E0 ; Reset Extruder
G1 Z5.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
G1 X0.1 Y20 Z0.3 F5000.0 ; Move to start position
G1 X0.1 Y200.0 Z0.3 F1500.0 E15 ; Draw the first line
G1 X0.4 Y200.0 Z0.3 F5000.0 ; Move to side a little
G1 X0.4 Y20 Z0.3 F1500.0 E30 ; Draw the second line
G92 E0 ; Reset Extruder
G1 Z5.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed

The above code will activate the heating elements but starts homing and leveling procedure without waiting for the elements to get up to temperature. Only after the bed leveling is finished the printer will pause and wait for the heating elements reach the desired temperature.

This will prevent oozing on a cold start, but you will still be affected if you start a print right after another print, when the hot-end is still close to  melting temperature.

If you prefer to avoid that condition you might want to also move the M104 and M140 commands after the G29 bed leveling command.


Using 2x CAT6 cable for 24 V hotend I'm looking to replace the troublesome ribbon cable of my Duplicator 6 with a 2xCAT6 arrangement for all things extruder.

Are 4 26AWG wires (2 sets of 2 twisted pairs) enough copper for 50W heater at 24 volts?
Are 2 26AWG wires (1 set of 2 twisted pair) enough copper for the ground connection of the heater?
Can I consolidate ground connections of the low power fans/sensors to free up more wires?
Is it okay if I have some pins be 24 volt like for the heater and others be 12 volt for the fans?
Should I get a lower gauge CAT6 cable like 24 AWG? 23 AWG seems to exist too.

Do not consolidate ground wires, use as many as the positive ones. In fact, use one wire of each twist for ground and one for the related positive, so that they balance each other.

Mixing voltages is fine, the CAT 6 cable will hold 24 V fine.

Concerning the number of wires, you should check the allowed current per wire and calculate the required number of wires.

Each pair can carry 0.36 A. 50 W is 2 A, you need 6 pairs for the heater.

You get two spare pairs, which can carry in total 0.7 A at the voltage you prefer. You could use two for the thermocouple and two for the fan, or two different fans.


Sunlight powered metal 3D printer Could concentrated sunlight be used to build a metal 3D printer, sintering or melting metal powder?

Related question on physics stack exchange https://physics.stackexchange.com/questions/143049/what-temperature-is-achieved-in-focus-point-by-5000-flat-1x1cm-mirrors-onto-a-sa

Let's start with the obvious: this printer would need to be really big. Not because of a large print volume, but because it needs to collect a lot of sunlight or needs a really big focussing array. The linked question states that the array there, about 0.6 m² large, has roundabout 600 W of power to focus on that one point.
Power draw needs
What powers are we dealing with?
A typical laser cutter uses a laser tube that at least 20 W for thin material and up to 300 W for thicker material. But we need to weld steel, so we need to be roughly equivalent to a cutting laser for the same material. We are not talking mere hundreds of watts, we are talking an industrial 2000 to 20000 W in a laser of less than a millimeter in diameter. Why do I say the later? Well, power need scales with the area, which scales with the square of the radius.
Let's use a ballpark, a nice round 10000 W Laser with a somewhat large 1 mm² crossection. We're talking about the ballpark of 100 Gigawatt per square meter.
$L=P/A=\frac{10000\ \text W}{0,001\times 0.001\ \text m^2}=10^{10}\frac{\text W}{\text m^2}$
Solar power harvester size
Luckily, we don't need to illuminate a whole square meter, so we only need some 10 Kilowatts of sunlight for our application. But we need this number to calculate how much sunlight we need to harvest in our smelting machine.
At the stratosphere, Earth gets about 1400 W/m², and on a sunny day, about 1 kW/m² makes it to the surface, we call this the solar constant $S$. Now, if we compare the ballparks, we get to quickly see the ballpark size of our machine:
$P/S=A=\frac{10 \text{ kW}}{1 \frac {\text{kW}} {\text m^2}} = 10\ \text m^2$
10 square meters of harvesting area gets us the same power. Incidentally, this scales linearly with the item discussed in the linked question, as that one already uses square meters.
Sizing down
But 10 square meters of mirrors into a focal point and then lenses to a focal point is huge, can we make it smaller? And to that I must say somewhat. First of all, we could get our focal point smaller: We need to get 10 Gigawatt per square meter for our $L$, but we can turn two screws here: what if we get from 1 mm² to only 0.1 mm²?
$P=L*A=10^{10}*(0.0001\times 0.0001)\ \text W=100 W$
100 Watts focussed on 0.1 mm² is a sixth of the power that array can deliver, so totally feasible in terms of power, as long as you can achieve such a small focal point.
Conclusion
Yes, with a focussing array good enough or a mirror array large enough you could achieve the powers needed to melt metals on a spot focus. Note though, that you need to have a really good focus setup that creates pretty much a solar-powered laser, which means that such a machine will be extremely expensive due to the high precision machinery needed for that - and that this focusing aperture will be most likely the largest part of your machine. We're talking building-size scale. I'd be cheaper and easier to just put lots of solar panels onto the roof of the building you run a conventional metal 3D printer in.


Ball valve to be prototyped Hey so theres a product we have been prototyping.
We cant do FDM. The item has a ball valve.
and the ball ~ 1.6-1.9mm
I cant seem to prototype it. I have tried SLS, SLA, Polyjet.
Anybody knows what could be wrong, or what should be the dimension i should be using?
I thought I would post this at engineering section, but since I have to prototype I thought its best if its in 3D Printing section

Edit:

Update:

So heres a figure showing the direction of air flow.

Update:
Thanks both answers are helpful. though not a precise answer. Then again, there is no correct answer.
Thanks a bunch. Lets see how the coming months are. :p

Hey why to make it soooo sophisticated and poor?
Air valve cannot be designed with 2 stiff elements - it will never work.

Make the air your friend but not the enemy. Use old good rubber (silicone) "flake" instead. Especially when you have such small design.

Take a look on the picture.

Here you have black element which is rubber or silicone. It's sticked on one side. When air goes from the pipe (goes up) then rubber is slack so the air can flow. When you suck then rubber seals the pipe.

[edit]

You can find such solution in for example bike pumps, inflatable matterss pumps also gas masks and so on. It's pretty fine for low pressure.

Of course ball valves are also widely use but then such device has to have "rubber" ball nest so ball lies on the rubber ring to seal it. There has to be a spring to tight the ball to the ring. Without such spring turning the device upside down would cause the valve would not work at all.
Ball solutions are intended to higher pressure.

Please note the spring which tights a ball creates kinda threshold on the pressure level which means that pressure has to exceed a spring force to reduce a pressure. This doesn't occure in rubber valve.

I don't know what device you are trying to prototype but I'm pretty sure a rubber valve will be just fine.

Please also note that sealing surface is very low in ball valve solution but in rubber valve it can be almost unlimited so it can seal quite well even when the surface is not perfect.


Is there any (relatively simple) way to determine whether a stepper is being directed to move by the voltage signal across its winding? This may be a long shot, but I was wondering if the signals seen across a stepper motor's windings could indicate whether the stepper was being told to move over some short time period.  This is in particular for the stepper used on extruders.

I've read that PWM in used in stepper drivers and controls current patterns to move the motor.  And that a current must also be maintained through the windings if the motor is to hold its position.  So it would seem that there is always a pulsing waveform across the windings whenever the stepper is energized, correct?  When the motor is holding its position, is there anything distinctive about the waveform?

This is for a filament sensor I'd like to make.  The sensor would be located at the extruder motor.  It would monitor movement/flow of the solid filament.  A lack of filament flow could be because of filament runout, tangled or caught filament, or non-extruding travel moves. I'd like to be able to tell the first two causes from the last one (when it's not supposed to be extruding for some hundreds of milliseconds or so).  It would also be nice to tell 'no directed movement' from 'very slow movement' which would happen with small nozzles, slow speed or other slow extrusion situations.

I watched the waveforms with an oscilloscope while printing, but travel moves were quick and relatively rare, so I couldn't definitely see if there was something I could use during those times. Could I just filter the pulse waveform (what corner frequency?) to get an approximation of the current waveform going through the coils -- on the idea that the waveform should resemble a DC level during non-extruding but still energized times.  Perhaps another low-pass filtering of that DC level, or a high-pass of the waveform to indicate directed extrusion?  Using DSP on a micro, of course.

Are there any experts here on the subject of low-level stepper motor control?

So it would seem that there is always a pulsing waveform across the windings whenever the stepper is energized, correct?

Correct.

  When the motor is holding its position, is there anything distinctive about the waveform?

Yes there is. This video contains a short example of what the current waveforms would look like.

If I understand you correctly: You want to detect filament events based by doing current sensing on the phases of the stepper motor. The simple of it is that, if the motor is not turning then the Back ElectroMotive Force will be zero. As the speed increases the BEMF goes up, which causes the current levels to go down. Is this how stall detection in some driver systems work.

You may be able to determine if what you want to do is even practical by studying the fundamentals of stepper motor driving; both voltage mode and current mode.

Apart from that it may be just as practical to use a rotary encoder upstream of the extruder motor to detect the filament movement, or lack thereof.

In your case detecting if the filament is present but not moving calls for stall detection. If the PWM pulse occurs but the rate at which the voltage increased (the slope) did not change, then there was no BEMF event. The lack of such an event would indicate that the rotor did not move. If there is no filament to push, then when the rotor moves it will ring (overshoot it's target position and fluctuate back and forth until it settles into the electrical position that the controller intended), because the mechanical load has changed.

For a NEMA17 stepper, these would be very small change in a very brief event. I would start with installing current sensors on both phases, and then doing some signal processing on top of that.


Infill is rough - how to enhance? My i3 MK3 is printing very well for solid parts of an object, but it messes up with infill.

As you can see in the image, the infill is broken into pieces and bends to that the surface becomes rough and the nozzle touches it next time it moves there, which probably does not make things better.

I've read the Prusa problem page, where they suggest three solutions:

change infill type
flexible filament (I'm using PETG, so this does not apply)
lower printing speed

I'm printing with 20% infill and I believe that this worked before at the same speed, so I'm tempted to say that both remaining options are options, but it should work without them.

It also seems to me as if the infill is thinner that ordinary walls. Is the extrusion speed lower in case of infill? Is there a way of changing the extrusion speed for infill?

Side note: my printer always tells me to upgrade to the latest firmware 3.5.1. Since I have just received the printer back from a warranty repair after the last firmware upgrade, I don't want to upgrade the firmware. Could the issue be related to firmware?

Infos requested from comments:

I'm basically using the Slic3r default settings for PETG. The only thing I adjusted is the temperature, since I'm using HDGlass PETG and there was a recommended temperature written on the spool. Relevant settings seem to be

Filament settings

fan speed min 30 % max 50 %
bridges fan speed 50 %
enable fan below 20 s
slow down below 20 s
min print speed 15 mm/s

Speed settings

Perimenters 45 mm/s
Small perimeters 25 mm/s
External perimeters 35 mm/s
Infill 200 mm/s
Solid infill 200 mm/s
Top solid infill 50 mm/s

From your comments can be read that you print infill at 200 mm/s.

Know that 200 mm/s is ridiculously fast (like high travelling speed), close to the limits of printing on certain machines (for an AtMega)! It is hard for the filament to keep up at this speed. A value of 60 mm/s would be a good value to start experimenting. Your infill is not rough, it just failed printing. I have printed kilometers of PETG, normal print speeds for my PETG are recommended at 30-50 mm/s by my manufacturer; I get good results at 50-60 mm/s. On my Ultimaker 3, 70 mm/s is also feasible.

Note that the filament you use seems to have rather low printing temperatures (195-225 °C) as opposed to the PETG filament (co-polymer) I'm used to. The manufacturer does not specify advised print speeds (other than "high", but what defines "high"?), but this user posted some of his print settings for this material. The overall speed of 60 mm/s seems to support lower than 200 mm/s print speeds.


M3D Micro printer stops extruding but is not clogged I have an M3D Micro 3D printer that printed fine for a couple of weeks and then was plagued with issues afterward. I've done the fixes from the forum to get proper heating and cooling of the nozzle (I've added aluminum foil around the nozzle to make sure the hotend is fit snug against the nozzle and I've added an external fan, powered externally, to compensate for heat creep).

This works very well for short prints and it usually finishes successfully. When I do a longer print it always stops midway and usually at the same exact point.

I tried printing at 200 °C with black PLA and then again at 215 °C with the same filament and it stops at the same exact point. I also tried M3D brand white filament. I am using CURA slicer with Octoprint GCODE sender and M3D Fio.

I know it is not clogged because if I stop the print and press extrude without letting it cool down, it extrudes fine.

What is causing my printer to stop printing?

I'm not sure how similar the two systems are, but I use a Stratasys uPrint SE Plus and I've run into a similar problem.

There are two rollers in the head that pull the filament through to the extruder nozzle, and in one instance they appeared to have heated up, melted the filament enough to create two "indentions" on either side of the filament, making it such that the rollers had no purchase on the filament itself. There was never any clog, no material feed error, but it was still failing to print. Wound up having to replace the head altogether.

Again, not sure how similar the extrusion mechanics are in the M3D, but suggest checking the components that actually advance the filament, and the filament itself.


Access uncapped 5 V output on 3D printer controller board Typically in Arduinos, most of the 5 V outputs that have a limited amount of current (40 mA).

Are there any 3D printer boards, or is there even a more usual spot, where you can get a 5 V output that isn't capped by the microcontroller?

I know that USB 2.0 is (typically) limited to 500 mA especally when connected to a laptop. Just wondering if there was a way to for e.g. get a 200 mA output from one of the 5 V pins, or more if there is a stronger power supply connected to the USB port.

Any pin that is labeled as "5 V" can supply the full amount of current. Looking at, for example, the Arduino MEGA pinout, we can see several pins labeled in red with "5 V". These are the pins you can use. Most 3D printer boards will expose the 5 V pins at several points. For example, the endstop connectors often have a 5 V pin that can be used.

The pins that are limited to 40 mA that you are thinking of are the digital pins, i.e. the pins that can be switched on/off by the microcontroller. These are actually more limited than this, and while in some cases drawing 40 mA from them may be possible, it is not a good idea.


Calibrating steps/order Does anybody have an overview of what things should be calibrated (and in what order) for a certain 3d printer or after changing the printing material?

I only know about:

calibrating the extruder steps per mm, e.g. Tom's youtube tutorial
determining the print temperature, e.g. RepRap Neo's youtube tutorial
calibrating the extrusion multiplier (for each different filament), e.g. RepRap 101's youtube tutorial

How to calibrate/determine the maximum speeds or accelerations?

How to Calibrate. Oh man that is a good 2-3 page long blog post.. So I will try to give you the bullet point section.

High level

Mechanical
Firmware
Software
repeat

Mechanical
Level everything. Bed. The X axis. Make sure there is no binding, etc. Also make sure the surface you are on is flat before leveling the printer by it.

Firmware
Get that printer moving. This is where you do you Steps per MM. I like Triffids guide.

Now is when you go into the software and start setting your slicer settings. This includes your filament measurements etc. You should go back 2-3 times between this step and the previous to make sure your extruding EXACTLY what you think you are. As mentioned by others filament calculation is hard. You need to measure across a lot of material. Take the averages. You will never get it perfect as the plastic is never perfect. Picking a solid supplier is a factor here too.

Once you think you have that all working. Repeat. Start at step one.

After your done looping though you will start with the slicer calibrations. Which is the meat of your question. You will take collections like this one or this one and tweak settings until you can pass each test. Do your tests in this order

single wall test
hollow cube
solid cube Here is a Bonus solid cube
bridging test (honestly I rarely do this one..)
part fitting test

Now for testing when switching material. Honestly its best to start with their settings, and tweak them. I like to have a spread sheet of xy speed, Z lift, temps. Massage it till you are happy. The firmware settings like jerk and acceleration will be less of a factor between materials. Get it perfect once and don't touch it (till you decide it is not perfect).

You will be testing the new material with the same STLs as I mentioned in the precious section. You also might want to look into Simplify 3d (no affiliation) if you get really into it. Also SAVE THE SETTINGS. Nothing sucks more then losing all this work and having to recreate these profiles for materials. Do not trust slic3r to back them up, or to not randomly delete them. Hard lesson there.

Far as max speeds and accelleration..

Max speed will really be a function of how fast can you hear up plastic. If you have a e3d with Volcano mod you can really crank the speed up. So you go to the point where your extruder just cannot hit target temps AND you are unable to print solid infill. Far as acceleration and jerk. When you knock your extruder causing your print to shift, then you know it is accelerating / jerking too hard.

Best of luck! Let me know if I can clear up a section for you.


How to prevent layer separation, when printing tall vase-like (tube) objects? I am experiencing a minor layer separation when printing a body for a tipping-bucket rain gauge, which is basically a hollow tube with thin walls (3 mm). I am using Prusa I3 MK2 and a Fillamentum ABS white plastic. The model has been sliced in Siplify 3D with the following settings:

layer height: 0.2 mm
perimeter shells: 3 layers (almost entirely
fills up the wall)
extruder temperature: 230 °C
printing speed: default - 50 mm/s, outline - 35 mm/s, infill - 35 mm/s

Is it possible to prevent the irregular and layer separation by adjusting some of the settings, and not significantly increasing the printing time, which is already 13 hours?

PICTURES:

The best thing you can do for a large ABS print is to have an enclosure heated to 50C or better. For example, see this, this, this, and other search results.


What is the best method of printing joints for action figures? I'm interested in 3D printing toy action figures, but what I don't quite know how the joints should be designed to allow flexibility.

I could imagine maybe something like a screw and nut for the arms and legs that are separated with a hole in the middle that can join them, but I don't know how to get a wider range of motion on shoulders and hips.

(NOTE: Converting comments to an answer.)

An interference fit would probably work. There are a couple of styles I can think of which would do. Here are some ideas from thingiverse.com which may work for your needs.

(image taken from this design by OgoSport)

With this style of ball/socket, you'd have very good articulation. More than enough movement to allow for a posable action figure.

Another idea from thingiverse.com is this:

(image from this design by NEMO_from_saturn)

The idea behind this style of joint is to insert it into each part (part fits over the end). This is premade and would be easy to utilize. The thing about this is, they are covered by the licensing involved with patterns found on thingiverse.

As with anything printed or mechanical, it will wear over time. You won't ever get anything which doesn't wear. It's just a fact of how it works. Some printed filaments will have better wear properties than others, like ABS, NylonX (polyamide with chopped carbon fiber strands), nylon, PET (PETG/PETT), or polypropylene (this is not all inclusive). Each filament has its own printing properties and idiosyncrasies, so pay attention to what needs to be done to print with them. This doesn't mean all of the parts need to be printed out of this material, but rather if using a joint (like the second image), you could print it out of the better wear material and print the rest out of filament which is cheaper and is easier to work with.


Best method to make dissolvable supports? Sometimes supports are very difficult to remove (physically) when I print with ABS. The image below, from Thingiverse - MOF-5 unit cell, is after significant effort to remove the yellow ABS supports from a black ABS model.

I've learned about polyvinylalcohol (PVA) as a 3D-printing filament which is soluble in water. It seems like a great option for dual-extruder printers, where you can print the model with ABS or PLA and the supports with PVA, then throw the whole thing in water and let the supports dissolve.

I've considered other options since PVA is ~4x more expensive than ABS.

Doing a PLA print with ABS supports, followed by dissolution of ABS with acetone, is my best idea currently.

Has anyone found success with another option?

I've had great success printing with HIPS (high-impact polystyrene) as a support for both PLA and ABS. Most sites recommend it for use with ABS because the materials melt at similar temperatures and work best with heated beds, but I've had good luck using it as a support material with PLA on a bed at 60°C. It doesn't stick as well to PLA as it does to ABS, so supports tend to peel away very readily. The downside is that, if you need the support to anchor your print at all, it doesn’t really stick well enough to accomplish this task. For that, you must pair HIPS with ABS.

When you print with ABS or have complicated interwoven support structures, HIPS can be dissolved with D-limonene, a citrus based cleaner sold under various names like Citrisolv (others exist), or with dipentene (a mixture of L and D-limonene that doesn't smell as pleasant).

Regarding cost: I've found HIPS to be slightly more expensive than PLA/ABS, but only 1.5x the cost, not 4x like PVA. Additionally, it isn't hydroscopic in the same way as PVA so it lasts longer out of the package. Since you're using it as support, you also tend to use far less filament than you do for the main print (sparse support structures as opposed to solid print structures).

Water-soluble alternatives: There are a few proprietary blends of polymers sold by the big commercial printer manufacturers (3DSystems, Stratasys) that only work in their machines… these are generally soluble in basic solutions (water + sodium hydroxide or sodium carbonate). These are usually very expensive and you'd have to rewind the filament on a spool, as they come in cartridges made for specific printers. You'd also have to experiment with the right build conditions and solution blends to remove the material afterward. Airwolf has a support material called Hydrofill that purports to be soluble in plain water… I'm not sure how this is different from standard PVA, though I assume it is different. Hopefully more companies will work on developing water-soluble options to help us keep the 3D printing world full of renewable, less-environmentally-harmful options for filaments (both print and support).

Update:

Ultimaker now has a material called Ultimaker Breakaway. After using it for a few models, it works remarkably well, allowing me, for the first time, to print nice rounded surfaces on the bases of my prints. It really does just break away from the surface, much like HIPS but without the lack of adhesion problems between HIPS and PLA.


Limit X axis due to direct drive Recently I printed this direct drive mod and installed into my Ender 3.
After installation, the stepper motor constantly bangs into the right Z frame of the printer. I have already set the bed X axis size to 190 mm within Cura slicer and my OctoPi printer profile but when homing, it will home to left and move towards right at a fairly fast speed and "BANG", I can hear the motor skipping a few steps, not sure how to proceed from here...

Try using a pancake stepper I heard those work quite well, they do have less torque but you can overcome that with gear ratio's like on the bondtech extruders. It should be thin enough so you can use the full volume again. If you dont think that's worth it you should move you X-axis endstop since the homing is where it goes wrong, as far as firmware goes I can't help you in that aspect as well as other would be able too. I hope this helps.


What is the best way to adhere an old printed part to the bed? I am currently trying to print a company logo on another part I have printed in a different colour. To try and maximise the strength of the part, I need to print the part on a different orientation to what I intend on printing the logo on. As a result I need to in a sense re-adhere the part to the bed so I can print the logo. I am using PLA filament on a spring steel sheet (the default sheet with a Prusa Mini).
Any ideas would be appreciated before I accept defeat and just glue the parts together.

I have not done this, but I believe this is the best method and I want to test it at some point soon:
Model a negative for the footprint of the part you want to adhere to the bed, in the orientation you want to adhere it, with just a few mm of height, and clearance suitable for your printer (probably around 0.25 mm) in the XY plane, and print that with thick extrusions on the initial layer so that it adheres well to your bed. It should look exactly like a "thickened brim" for the part you want to re-adhere. Don't let the bed cool after printing it.
Now, you have a slot to insert your part into that will not only hold it to the bed, but holds it to particular coordinates you chose to print at, which you can align to the coordinates of the new model you want to print on top of it.
If you can't get the clearances right to hold without knocking off the negative footprint from the bed, you could try adding some threaded holes to it, so that you can put a couple set screws through it to hold the part in place. This technique can also be used if you want to avoid modeling a full negative (e.g. if you don't have the original in CAD form where you can easily negative it) - just print a few posts to hold set screws in approximately the right places on the bed.


Can 3D printer models be used in video game engines and vs versa? If someone creates a 3D model of a character for 3D printing can I import that model into Unreal engine or Unity 3D for use in a video game? Also is the inverse true? Can I get 3D model of Mario and send that to a 3D printer?
Specifically, it’s more important to know if I can pull a 3D printer model into an unreal game project

Yes. You can import it into Blender, but it will need "bones" and "armature" if you want it to move at all.   In Blender, you can manually add armature and "Rig" it, if you want animations.
You can probably convert whatever file type the 3D model is (probably STL) to fbx with Blender
For animating, start with a super basic 2-bone rig YouTube tutorial, then learn about vertex weights or automatic weighting.
But you'll have to UV map it too. The UV map tells textures where to go on the model, STL doesn't have those.
Your time is 100% better spent finding a model that's ready and moving on with your project.
Check Unreal Marketplace.
Also,
https://www.turbosquid.com/3d-model/free/low-poly/character
https://www.cgtrader.com/free-3d-models/character?polygons=lt_5k


Why use G29 during a print? Why do printers, like the Ender 5 Plus, execute the G29 routine prior to every print?  I understand the purpose of this step when MANUALLY leveling the bed since you are presented with the 16 measurements and can adjust the four corners of the bed.  However, from what I can tell, there is no way any of the printers out there (Creality, and others) to actually level the bed.  Since there are only TWO Z-axis motors... one on each SIDE of the bed... then, at most, the only thing the printer COULD do at this stage is to gradually TILT the bed from side to side to adjust the height of the left or right side.
Now, all of that aside, I guess, in theory, it WOULD be possible for the printer to use these 16 measurements to dynamically ADJUST the height DURING THE PRINT based on where the head is SUPPOSED to be versus where the ACTUAL height of that spot actually IS.  However, I cannot find anything that claims this is what happens.  From everything I find, the G29 routine is run and is done.  This means you can only benefit from it during the manual leveling process.
Am I missing something?

Now, all of that aside, I guess, in theory, it WOULD be possible for the printer to use these 16 measurements to dynamically ADJUST the height DURING THE PRINT based on where the head is SUPPOSED to be versus where the ACTUAL height of that spot actually IS. However, I cannot find anything that claims this is what happens

This is actually what happens. This behavior is clearly specified in the firmware documentation:

Mesh leveling measures the height of the bed at several points to generate a 3D mesh representing bed imperfections. With compensation enabled, the nozzle follows the bed contours by dynamically adjusting the Z position (using bilinear interpolation between the measured points). The nozzle follows the contours of the bed more accurately with more mesh points and/or finer segmentation of moves.


Which material should I use to print a mounting adapter for the y-carriage? I have purchased a replacement bed for my 3D printer. I wish to have it mounted on a single linear rail.
Currently I am unable to drill properly into aluminum (due to problems with my drill).
Therefore, I'd like to print and use an adapter piece/plate to fasten the Y-carriage to the linear rail block. The bed has a thermal insulation foam so the area around the bottom of the Y-carriage plate/bed assembly doesn't seem to go over 60 °C.
My question is:

Which material should I use for this adapter piece, and why? (I have access to PLA, PETG and ABS.)
Should I use threaded inserts or fasten the Y-carriage with nuts?

Please see the image below to have an idea as to what I mean by an adapter.

Any thermoplastic is a bad choice to carry a heated bed. For an unheated bed, monolithic (cast, not printed) acrylic plate of sufficient thickness can be used.
To get the needed stiffness and temperature resistance, steel plate of about 2+mm is the best choice, followed by aluminium of a higher thickness. The latter can be sawed with woodworking equipment, if done slowly.


Are there biocompatible materials available to the general public? I am currently working on parts for a custom prosthesis.

My main concern at the moment is to find biocompatible materials that can be 3D printed from a UP or a Reprap.
The piece would need to be in contact with the skin for extended periods of time, probably around 17 hours a day on average.

The main concerns I have are:

Skin reactions caused by prolonged contact
Skin reactions and bruising caused by friction
Degradation of the materials due to prolonged exposure to skin secretions and sweat
Risks of toxicity in the compounds generated by the aforementioned material degradation

Which materials can you recommend?

Any extensive data (from testing) would be greatly appreciated.

There are printers designed for medical use, and the manufacturers supply them with varying levels of certification and testing, however I've not seen a filament manufacturer certify their material as bio-compatible separate from the printer. The printing process changes the material slightly in the best case (and significantly with poor temperature control or badly set parameters), so even if bio-compatible filament were found, the resulting product might not achieve the same level of bio-compatibility.

If your intent is to use hobbyist level machine for medical purposes, you might simply want to use an interface, such as a sock or a molded/cast polymer that you know to be bio-compatible between the printed part and the skin.


What hairspray brands are known to contain PVA / PolyVinylpyrrolidone It's common to use hairspray, especially AquaNet, as a bed adhesive. My understanding is this works because the spray includes a chemical called polyvinylpyrrolidone, or PVA.

What other brands of hairspray are known to contain this chemical in sufficient concentrations to work as an effective adhesive in 3D printing applications?

From an MSDS for AquaNet hairspray:

  Water (Aqua), Dimethyl Ether, SD Alcohol 40-B (Alcohol Denat.),
  VA/Crotonates/Vinyl Neodecanoate Copolymer, Acrylates Copolymer,
  Aminomethyl Propanol, Sodium Benzoate, Cyclohexylamine, Triethyl
  Citrate, Cyclopentasiloxane, Sodium PCA, Masking Fragrance (Parfum)

The MSDS doesn't mention polyvinylpyrrolidone.

I suspect that the "PVA" here is the VA/Crotonates/Vinyl Neodecanoate Copolymer.  A little googling indicates that this is a common ingredient of hair sprays, and works by forming a thin coating over hair to prevent it from adsorbing moisture.

I stumbled upon three types of Loreal(R) hairspray that have these ingredients.  It seems likely that there are more.

Disclosure:  I use AquaNet on an aluminum bed as a PLA bonding agent, and on my Prusa PEI covered bed as a PET-G release agent.


Printing with HDPE plastic Just out of curiosity is it possible to print with HDPE?

Would it be easy or hard?

I know they don't make HDPE filament* but I know people with a filament extruder could make some HDPE because it is a common plastic, which means it can be given a second use or something.

*To my knowledge

It can be done, although PE is not the best material to 3D print, as it has very low melting point (HDPE is just over 100°C), it is unpleasantly waxy to the touch and needs specialised paints and glues.

I never tried myself, but I know the RecycleBot is supposed to be able to use PE waste to produce a filament.


Will Mod Podge work with PLA prints? Looking for something to smooth out a PLA print. Would Mod Podge be a good solution? Will it stick?

From what I've read about Mod Podge, it is an adhesive with a vinyl acetate base. As such it is similar to both PVA (used for wash-away support) and ordinary white glue. One of the more common references to the product refers to it not being water proof, although the outdoor version of the product presents as being water-resistant.

As part of the research for this answer, I found references to overly-thick coats becoming milky. This follows a reference to applying thin multiple coats and allowing proper cure time between coats. That proper cure time is listed as 28 days.

Another set of posts suggest to cure the MP more rapidly than 28 days, one can heat the item in an oven to 175°F (80°C) which should not cause the PLA to melt, but may allow for sagging of unsupported parts. Testing is recommended.

MP is an adhesive, is known to stick to non-porous surfaces and would be no more harmful than glue stick for a PLA (or ABS) model.

Durability is uncertain. If you intend to paint the item after sealing/smoothing, you'll gain durability and water resistance.


When I attempt to calibrate extruder steps the increased values don't correspond to physical increases I am attempting to follow these instructions to calibrate the extruder, however when I increase the value for DEFAULT_AXIS_STEPS_PER_UNIT the change in physical output does not correspond with the changes.

I started by testing how much filament goes through the extruder when sending G1 E100 F100 to my printer, instead of the 100 mm I get about 38 mm (#define DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 400, 93 } in Marlin). I increased the value to DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 400, 149.73 } which should take it to 100 mm, when I tested the physical output the increase was only negligible so I repeated the calculation with DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 400, 387.8007 } as the new value. The new physical output is about 64 mm, I think this suggests a mechanical problem rather than a firmware configuration problem, but I am not sure where to go from here.

My printer is the Ender 3, running Marlin 1.1.9 with a BlTouch and an aluminium bowden extruder mod

(installed after the extrusion problem began).

Any help you can give will be greatly appreciated.

Mechanical?

You basically answer your own question that there could be a mechanical issue.

If 93 steps gives you 38 mm, to get to 100 mm, you need to divide 100 by 38 = 2.63 times. This implies that you need 2.63 x 93 = 244.7 steps/mm (not 149.73).

You even tried close to 400 steps per mm to see you are not extruding 100 mm of filament. This implies that you are either missing a lot of steps (increasing the stepper current or increasing the temperature of the hotend would help out) or the extruder gear slips on the filament (increasing the pressure on the extruder gear and filament could solve this).

Or not mechanical?

Furthermore, it could be another issue than mechanical. If your extrusion rate is too fast, the stepper might not be able to cope the high speed and miss steps. I have had this before with a too high of a retraction speed.


First layer prints too thin causing gaps everywhere I'd assume insufficient z offset but some areas of the first layer look fine. I've been struggling with this problem despite lots of attempts including z offset, infill overlap, belt retensioning, etc.

Anyone else experienced this type of issue and have suggestions to fix it properly?

I'm using polylite PLA and a E3D steel nozzle. 60 °C bed temp, 230 °C first layer.

Edit: Print speed is 30 mm/s first layer, 60 mm/s normal. This issue occurs on the first few layers then the rest get increasingly better, with the final layer being excellent.

Edit2: Despite lowering the temp to 205--210 and increasing the z offset downwards, the problem persists, though to a lesser degree. Just gaps at ends of infill lines and between straight and circular walls. But seems it only occurs on the lower left and upper right (birds eye view) of the print.

Edit3: The lower left and upper right being further from the nozzle coincides with my removal process using the knife on the lower left and upper right.. Maybe this part of the problem I'll have to bend back in place?

Nozzle bed measurements below:

Edit4: Optimizing the Z offset according to the first layer thickness remained only a partial solution especially as my bed unevenness (1mm+) was past the auto-leveling limitations (<0.5mm), but I found a great thread (link below) with a "correct" solution that worked for a lot of people! After I try this I will come back and write about my experience with the solution.

https://forum.lulzbot.com/viewtopic.php?f=36&t=7904&hilit=bed+leveling+SOLVED

From the picture it is clearly seen that the filament is not flattened properly. This implies that your nozzle bed distance is too large. Try decreasing the gap by leveling the bed at temperature and have a piece of "A4" or "Letter" print paper between the nozzle and bed have a little friction when pulled.

Also reduce the temperature, 230 °C is too hot for PLA (unless your printer temperature is way off, but that is not very likely), try 200 °C.

Another thing that you could check is if the extruded length is exactly what is instructed to be extruded; i.e. calibrate the extruder.


Problems with elephant's foot I recently got an Ender 3 Pro for my birthday, and I am having some problems with elephant's foot (as the title suggests). I have tried several fixes; lowering the print speed, changing the print micron size (quality) in my slicer, and I have also tried the masking tape trick (it definitely does not work). I want to know if there are any other ways to prevent elephant's foot on my prints. I first noticed it on a game-cartridge holder. It was four and a half millimeters thick on the bottom. I think that it could be an issue with the design, but I'm not entirely sure. I can send the specs for the design if you want to look at them.

Elephant's foot can be caused by different causes.

Incorrect leveling or incorrect nozzle to bed distanceThis answer describes that it can be caused by a too low nozzle to bed distance.
Bed temperatureA too high bed temperature and weight of the print can cause bulging out of the bottom layers. This also frequently occurs as the result of an uncooled/too less cooled first layer.

Improved cooling, lowering bed temperature or adjusting nozzle to bed distance and proper leveling are the most obvious solutions to fight this problem. Other solution can be found in using chamfers on the bottom of the print (requires modifying the model) or printing on a raft, this latter solution does lead to losing the nice bottom layer finish.


How to tell if A 3d printing kit has a replaceable nozzle I was looking at the prusa i3 3d(the original i3, not the mk2) on sale and I wanted to know how I could tell if it(and printers like it) had a replaceable nozzle, since I wanted to try out different nozzle sizes, and I need to be able to use a .1 mm nozzle for micro armor 3D printing(8mm height miniatures, I'm not too picky about their appearance) so anyways, does anyone know how to tell if a printer has a replaceable nozzle?

Prusa has a replacable nozzle. Usually all printer does have an replacable nozzle. Since this is a part of a printer which could get jammed during a printer life.

As written here: https://www.prusaprinters.org/prusa-i3-is-now-1-75-mm/ The Prusa i3 uses an E3D Hotend. This Hotend has many diffenez nozzles. You can search on E**ay for E3D V6 0.1mm nozzle and you will find a lot of offers.


PLA print warping on heated bed I am trying to print the 3 jaw lathe chuck on Thingiverse. This specific piece is the scroll.stl, but it applies on every big piece. The print material is (transparent) PLA, that I print on custom glass bed, which is heated by a regular heated bed at 65 °C. However, my print is warping on the external edges of a solid 2 mm for a 85 mm diameter print.

I didn't use the cooling fan. And I don't have an enclosure to keep the warmth inside the printing area. The nozzle temperature is around 200 °C.

What could be wrong?
The printer is a slightly modified Prusa i3 MK2.

Several things I've done to stop warping when it occurred:

Use a wider brim.
If the brim isn't sticking, use a higher bed temperature for the first layer.
If the brim comes up only on one side or warping is only on one side, make sure the bed is level.
Slowing down the print will keep you from having as long of a strand cooling down.  This will lower the contraction force and reduce warping.
A hotter bed temperature will reduce the temperature difference between the extrusion and the bed, thus reducing the contraction force.

200 °C is a good temperature for getting PLA to stick.  I've tried lower extrusion temperatures to reduce the temperature difference between the extruder and the bed, but this decreases adhesion to the bed and is counterproductive.


Makerbot Smart extruder+ heat block and nozzle question I am looking for information on the smart extruder+ heat block and nozzle?  I have looked online and from several forums come to the conclusion it is either a MK10 or MK11 assembly.  Can anyone shed some details on the heat block and nozzles.

Caveat emptor: This answer is probably not what you're expecting.

As far as I can make out after looking at this un-jamming video on YouTube, where at time 00:01:24, the video shows a label that needs to be cut to open up the extruder. However, as mentioned at the end of the same video, cutting that label will void Makerbot's warranty cover on the extruder.

From that, I can make out that Makerbot will actively discourage any efforts to disseminate the kind of information you're looking for, at least until the product is discontinued. That would usually include a DMCA takedown notice to Google to remove search engine results, as well as similar takedown notices to other places where such information is hosted. I expect you will not find such information easily.


On which board can 32 bit Marlin run? Does anyone know on which board that can be bought today is possible to run current Marlin x32 ?

The  platformio.ini file, given in Zac's comment, does not seem to list all of the boards supported.

However, The Marlin 2.0 32-bit thread appears to have a table that is much more complete (at the time of writing):

Board                           MCU         State            To-Do
RAMPS, etc.                  Arduino AVR    good
Due, RAMPS FD (v2.A!), etc.  SAM3X8E        good
Archim 1.0                   SAM3X8E        ❓unknown    Only US$170!
Archim 2.0                   SAM3X8E        beta       needs confirmation
Re-ARM                       LPC1768        beta       NEOPIXEL_LED,M100,ENDSTOP_INTERRUPTS,Tones,etc.
MKS-SBASE                    LPC1768        beta       NEOPIXEL_LED,M100,Tones, etc.
Smoothieboard                LPC1769        beta       NEOPIXEL_LED,M100,Tones, etc.
Azteeg X5 GT                 LPC1769        beta       NEOPIXEL_LED,M100,Tones, etc.
Cohesion3D Remix             LPC1769        beta       NEOPIXEL_LED,M100,Tones, etc.
Selena Compact               LPC1768        beta       NEOPIXEL_LED,M100,Tones, etc.
Malyan M200                 STM32F103C8     beta       EMERGENCY_PARSER,NEOPIXEL_LED, etc.
Borg                        STM32F765ZGT6   ⚠beta       EMERGENCY_PARSER,NEOPIXEL_LED, etc.
Chitu3D V3.9                STM32F103ZET6   alpha      EMERGENCY_PARSER,NEOPIXEL_LED, LCD, SDCard, MAX6675, etc.
Teensy 3.5                  MK64FX          alpha      (need shields)
Teensy 3.6                  MK66FX          alpha      (need shields)
STEVAL-3DP001V1             STM32F401VE     alpha      (need boards)

From [Question] Most promising 32 Bit Platform for Marlin 2.x

  The reference platform IS Re-Arm with a RAMPS shield. You can find instructions for both obtaining it and getting setup with it at #7076

It appears the you have to use the bugfix branch:

  Right now, there are two branches. Bugfix-v1.1.x and Bugfix-v2.0.0. They are almost identical from a feature set perspective. But Bugfix-v2.0.0 is modified to have a hierarchical file layout. That was needed to clean up the code and to support 32-bit.

  The AVR code is fully debugged and working in both branches. The 32-bit code only exists (and works) in the Bugfix-v2.0.0 branch. And while the code does work... And some people are using it to print, it isn't entirely painless to get to that point.

You may also want to read Recommendations for a good 32 bit microprocessor to run Marlin. To list a few examples:

Atmel ATSAM3x8e on the Due board
Anyhow, there are a lot of 32bit Controller. Take a look at mbed.org for example.
You can use the arm-none-eabi-xxx for STM32, LPC, also the Arduino Due use it
Duet board (now called DuetWifi) is available for pre-order. It has a 120MHz Cortex M4 with hardware FPU
AZSMZ ARM 32bit controller board
RedBear: https://redbearlab.github.io/arduino/package_redbear_index.json

RedBear Duo (Cortex-M3, WiFi + BLE)
RedBear discussion forum

Konekt Dash/DashPro (Official): http://downloads.konekt.io/arduino/package_konekt_index.json

Cortex M4-based global cellular dev kits, support for all board variants, support for USB and over-the-air programming straight from within Arduino IDE

Another link that might be useful is Unofficial list of 3rd party boards support urls, although not all of these are 32 bit.


Raised lines on top layer surface Ender 3 I have an Ender 3 for two weeks now, my first 3D printer. I think I have a problem with top layers. See the left 3 stones on the first picture. It looks like lines and it feels like raised lines. The outer lines (walls) are perfectly flat, but the surface in between has heavily raised lines. I started with the standard Cura profile for the Ender 3 and tried .2 and .12 mm layer height, 2-5 top layers, 1 to 2 top surface skin layers and 5-20 % infill, all gave similar results. The only setting that solved it is the ironing feature (the fourth stone). While this solved it, it feels like I'm hiding an error in my printing with this feature and I would like it to print decently without ironing. The cat shows that my printer prints fine if no top surface is present. I have an Ender 3, upgraded with some fan guards and bowden clips and use Cura 4.5. SKR mini E3 and upgraded bowden tubes are on the way.

Is this normal?
What could be wrong?
Is ironing a commonly used solution?
Any idea what might fix it (apart from ironing)?

I would firstly do a flow rate calibration:https://www.thingiverse.com/thing:2490893

print this using: 0.2 mm layer resolution;0.4 mm layer width; wall count= 2; infill=100%
print it at the same temperature you printed the cat.
measure the walls width a couple of times in different places, get the average and then do : 100*0.8/average. the result is your new flow rate or extrusion multiplier.

I would then do a E-step calibration, use this:

Once you have this two parameters, re-print the block. I would suggest to print not faster than 50 mm/s and raise it by 5 mm/s if you see the thing is going right. Try a typical grid-20 % infill with 3 top layers and 1 superficial layer (usually you shouldn't need more than one). For these trials try scaling the blocks by 50% so you don't waste that much material. Try not to use the ironing function yet, you should get a uniform surface without it.

The weird thing is the holes pattern you get in all the pieces. Just in case, tighten your x and y belts, re-level your bed and try moving the extruder with your hand (gently) to see it doesn't wobbles.


Material for printing flowerpots I want to print a flowerpots, for advanced watering system.

Plants are going to be eaten.

What is the most suitable material, when we consider the fact, that we do not want to just make forms and do clay flowerpots(which may seem most healthier), but having them directly printed.

What are the temperatures that makes plastics emit dangerous components in surrounding water, and what are those components?

Is there some "totally safe" material out there? I was thinking of PLA or PETG, because I've already heard that ABS is not safe for edibles.

I printed some pots for sprouting seedlings this year from PLA.  A square array of pots with tiny drainage holes in the bottom.

The array filled the bed of a Prusa3d i3m3.

The seeds sprouted, except for the ground cherries, which I think failed because the seeds were bad.

I had good germination rates for tomatoes and basil.

According to the FDA, ABS is generally safe for food, although like any filament the pigment and any added chemicals may be contraindicated for continued health.


How to add internal supports/localized infill, preferably in Cura? I'm currently designing a very large and complicated model, because it's large and should be strong enough completely hollow I want to print it with no infill to save material.

However, there are some points in the model where there are indentations in the top shell.

The bottom of those indentations are lower then the surrounding shell (pretty mush the dictionary definition of indentation) and so they are printed earlier with nothing to connect to.

For example, in the image below from Cura's layer view you can see two round surfaces just hanging in mid air

Obviously this can't be printed.

What I'm currently doing is designing internal spaces inside the model where the internal space shell is holding the "detached" surfaces.

What I want is a mostly automatic process that will generate a support structure inside where needed or that will generate infill but only between the floating surface and the nearest solid shell below it.

Reorienting the model is not an option because a. it wouldn't fit on the build plate and b. even if it did it has a lot of internal parts with different orientations so it would just move the problem from one part of the model to another.

I usually use SketchUp for designing and Cura for slicing so I prefer something I can do in Cura - but since I strongly suspect this can't be done in Cura I'll accept answers that work with other tools

I'm not really sure if i get you right but it seems like you gotta switch on support material. That's all. Correct me if I'm wrong but it sounds like very common situation where some parts are hanging like your yellow disks.

Otherwise if your model is going to be closed at the bottom and at the top you can mock support on your own to have better control of it. How? Just add hollow cylinders under your disk so in fact cylinder will stay on the bottom layer then its walls will be support and finally your yellow disk will be a top cover of the cylinder. I hopw you can imagine that properly.

Another way is to design support elements wich would grow out of walls and this way support your disks

Maybe if you would explain a bit more, what the model is then I could support you more.

[edit]

To make it more automatic, you could try to use parametric CAD apps. I would say, Autodesk Inventor is one which I can suggest. You can use for example its Ribs functionality as support (varsion C).

[edit2]

After Tormod Haugene's and tbm0115's comments I decided to fill some gaps in my answer. Here go pros and cons of options A, B and C.

option A

The simplest one and more or less automatic one. Which means when user add support then this option will be a result of it. Of course if user needs to have support only for the disk but over the disk there will be... a "ceiling" then option A cannot use regular support as it will generate a support also for the ceiling. For such situation user needs to add a cylinder manually (filled one) or

option B

User can add hollow cyliner (just its walls). This option can give similar or higher stiffness as regular support because solid walls increase endurance tahn thin support grid.

option C

This option (my personal choose) has some advantages unavailable in A or B option. First - support doesn't have to have "ground" base. It means the yellow disk can really hang even if there is no bottom layer at all. Second - it joins walls with disk and walls together so the stiffness concerns other surfaces.

Depending on needs the cylinder (option A or B) can be transformed into a cross or pillar (thinner than cylinder itself). It can be more taper expandint to the top or to the bottom.

There could be even option where the above one would be joined with option C. So these (3) ribs would raise from the bottom but not from the walls.


Linear advance calibration technique Marlin has a Linear Advance calibration pattern generator, but I find it's hard to use because:

It only prints the initial layer on the bed, where bed irregularities interfere with accurate reading of it.
It doesn't do proper retraction and priming, so a mess of strings and underextruded initial segments/non-adhesion mess up the results.
It's hard to visually evaluate.
Getting a very wide range of K values involves multiple runs.
It's hard to clean up.

Is there a better procedure for calibration of K value for linear advance?

The same effect as Marlin's test pattern, with alternation between fast and slow segments, can be achieved with a skewed tower and Cura's overhang settings, providing the opportunity to interactively adjust K value during the print, or insert changes at particular layers in the gcode for automated test towers.

I'm using the following OpenSCAD to make a skewed cylinder:

multmatrix(
   [[1,0,1/8,0],
    [0,1,0,0],
    [0,0,1,0],
    [0,0,0,1]])
cylinder(d=40,h=40);

with Cura set to:

no top/bottom layers or infill
single walls
treat walls with 1° overhang as overhangs
print overhangs at 25% speed

These values can of course be tuned, but the extreme low overhang angle and 8/1 slope is to prevent actual physical overhang-printing considerations from messing up the test.

Vase mode might work even better for this if it supports overhang settings, since it would avoid the layer seam.


Are Fusion 360 drawings sufficient to design and enforce tolerance in a hole of a solid? I uploaded a 3D object for this project to Fusion 360 and printed it out straightforward:

Yet its middle hole is too small for the stepper motor (Nema 17 Stepper-M) I am using so I wanted to increase its tolerance before reprinting it.
So, I followed the tutorial by Tyler Beck of Tech who lead me to drawings:

I was wondering if doing a drawing (sketch in Fusion 360) was sufficient to expect the shaft of the step motor to go through?
Here are the gear and the shaft before I add the drawing constraints:

Besides offsetting the clearances you want into models, you can and should also calibrate your printer to compensate for included holes - because often inner holes are solved to be smaller than actually designed out of necessity.
However, the option can also be used to fix problems that stem from the slicing and printing itself, and thus offers to fix some problems that are endemic to your setup or where you can't easily fix the model by setting an offset to create the wanted clearances in it.
In Ultimaker Cura, the option for this fix is called Hole horizontal expansion since 4.6 in April 2020, which only affects internal perimeters as I know from testing.
SuperSlicer, a PrusaSlicer branch offers hole_XY_compensation, though I can't quite pinpoint the time when it was added. I guesstimate sometime before October 2020.
PrusaSlicer offers XY size compensation, which does affect outer perimeters. A hole-only is requested almost since that option was available the first time. An attempt to implement a hole-only compensation again appears to be worked on since mid-2020. It seems that in the beginning of March some implementation has been tested.
The first work for such a function was tried by Slic3r before PrusaSlicer was started on, using an Arc-compensation formula in at latest 2009, but the function proved to be overcompensating. As Prusa-Slicer is a fork of Slic3r, some of this work might remain in the code.


Adding custom M or G codes to Marlin 2.0 Adding custom M Codes to Marlin doesn't work for Marlin 2.0

How would one go about adding custom G codes or M Codes to Marlin 2.0? The Marlin_main.cpp file does not exist.

In general for Marlin 2.0, things are organized better, but split into more files.

The code in 2.0.x is similar to the old branch 1.1.x, G-code is parsed in gcode.cpp, specifically in process_parsed_command:

void GcodeSuite::process_parsed_command(const bool no_ok/*=false*/)

In the case statement the codes read from the G-code files are parsed (interpreted) and the appropriate method is called (e.g. G28() calls void GcodeSuite::G28())

If you want to create your own codes, it could be an idea to start there. Also think of using a different letter and/or codes in the 10,000 range so that it will not collide with new implemented G-codes.


CoreXY Carriage moves on the Y when moving the X I have a custom designed and built CoreXY printer. I have noticed that when I order the X to move from one side to the other (right to left) that the Y axis moves back about 0.6 mm as well. When I move the X back (from left to right) the Y also moves forward approximately the same amount.

What property of the CoreXY system could be causing this? Note, I am using 608 bearings instead of toothed idler pulleys; which I hope to rectify soon.

Steps per mm from the Marlin configuration.h:

DEFAULT_AXIS_STEPS_PER_UNIT   { 475.79, 482.87, 468.66, 188.1 }

Note, they are not the same for X and Y. This is because I am trying to run a calibration cube test on the machine.

For a CoreXY printer to move an axis (X or Y) it requires both stepper motors to turn. If both turn the same direction (at the same speed with the same pulleys), the X-axis will move, if they rotate both in a different direction (at the same speed with the same pulleys) the Y axis will move (see image of CoreXY kinematics below). Rotation of a single stepper would cause a 45° printing pattern.

All four corner points (two top pulleys and two bottom steppers) are fixed to the CoreXY frame

It is therefore highly illogical that you need to use different values for your steps per mm (X = 475.79 steps/mm, Y = 482.87 steps/mm). If you need to use such values, this implies that your mechanical layout/mechanics is/are incorrect (skew frame, different pulley diameters, slip on pulley, incorrect tension of belts, etc.). It is advised to make them equal and check the mechanical layout and inspect all parts (pulley diameters) and make the tension equal (e.g. using a Belt Tension Gauge). If the head still moves in the perpendicular direction as commanded, you could try to calibrate from there.


3D Printer seem to "Forget" Tool Path I've run into a strange error that keeps reoccurring my with my prints. Part way through the printing process, it appears that the printer "Forgets" the tool path and stops all together or starts to move in random patterns. It still extrudes material and the result is mess of wasted filament.

At first I thought this might be a levelling issue, but this does not appear to be the case. This only seems to occur on prints taking longer than maybe 2-3 hours. Does anyone have any idea whats going on and how to correct it?

I am running an Ultimaker 2 Extended with using Cura for slicing.

I believe what you are experiencing is the stepper motors getting offset during  the print, usually due to the nozzle colliding into the model (but possibly also due to very high printing speeds).

Basically, the stepper motors used in most 3D printers will always make moves relative to their current position (as opposed to absolute positioning). In other words, the stepper will for example be told to move 10 steps left, regardless of where it is currently at. If you therefore forcefully move the printhead out of position during the print, the electronics will never know it happened, and continue with instructions that are no longer viable.

In order to fix this, do what you can to avoid the nozzle colliding into the model:

Make sure your printer does not leave large deposits of filament, typically due to over extrusion or too close Z-leveling of the first layer.
Make sure the model sticks to the bed, so that warped parts don't lift up, obstructing the toolpaths.
Add Z-lift in your slicer software, so that the printhead lifts slightly between travel moves.
Reduce travel speed (if it is set very high): the strength of stepper motors is lower at higher speeds, which means nozzle collisions at higher speeds most likely will offset the motors.


How to connect a NEMA 17 stepper to RAMPS 1.4? I have an NEMA 17 stepper motor 17HS4401 and a RAMPS 1.4 driver unit.

The motor pinouts are:

RED   A+
BLUE  A-
GREEN B+
BLACK B-

while the RAMPS board has the following:

2B 2A 1A 1B

Could someone point me in the right direction? How can I connect the driver to the motor? I have a feeling I already messed things up.

There are very many combinations that will work. A bipolar stepper has 2 coils. Swapping the coils, or reversing the polarity of a coil, will simply cause the stepper to rotate in the opposite direction.

On RAMPS, one coil should connect to 1A and 1B, whereas the other coil should connect to 2A and 2B.

On the stepper, one coil is A+ and A-, the other coil is B+ and B-.

A possible wiring is A+ to 1A, A- to 1B and B+ to 2A and B- to 2B, but there are 15 other possibilities. The only "wrong" way is one that connects a coil of the stepper to two different coil outputs on the RAMPS (so connecting, for instance, A+ to 1A and A- to 2A wouldn't work).


Help to reconcile nozzle diameter, deposited line width, and wall thickness in Cura I need help resolving some conflicting logic between the nozzle width and shell thickness--parameters in Cura 16.021--and the physical deposited line width (width on x-y plane).

DEFINITIONS

For clarity, let me define a few terms I'm using:

Nozzle size - nominal diameter of the nozzle / Cura parameter

Nozzle diameter - true diameter of the nozzle

Extrusion diameter - diameter of circular cross-section extrusion upon leaving the nozzle

Deposited line width - width of the rectilinear layer deposited on the build surface in the x-y plane (not the z-layer height).

Shell thickness - Cura parameter for part wall thickness

Cura - Cura version 16.021

PROBLEM 1

Physics suggests that for regular continuous flow out of the nozzle the extrusion diameter (cylindrical material extrusion) would be slightly larger than the nozzle diameter, and the deposited line width (rectangular prismatic extrusion) on the x-y plane should be even wider than the extrusion diameter.  I'm assuming the deposited line width is equal to the shell thickness as set in Cura.  However, I am finding conflicting advice as to whether one should set the shell thickness slightly greater than or slightly less than the nozzle diameter.

In this post on the Ultimaker forum, the moderator seems to suggest that the nozzle size and deposited line width are one and the same.

In this post on StackExchange, the discussion seems to agree with my understanding.

PROBLEM 2

A commonly referenced procedure for calibrating extrusion suggests printing a 25mm cube with an open top and bottom.  My understanding is that by printing four walls of a single shell thickness, we should correct the extrusion rate to achieve a deposited line width equal to nozzle diameter (Cura requires the shell thickness to be a multiple of nozzle diameter) .  The problem I have with this is, as stated above, I don't understand a physical basis for targeting nozzle size = shell thickness (deposited line width).  I'd expect to calibrate the extrusion to something slightly wider than the nozzle diameter.

My printing experience seems to confirm my intuition.  If I reduce extrusion rate to achieve shell thickness = nozzle diameter my prints appear visually under-extruded with poor layer adhesion.  Calibrating to about 110% of the nozzle size looks about right.

PROBLEM 3

Although Cura constrains shell thickness to be a multiple of nozzle size, it will not slice thin shapes on the x-y plane equal to nozzle size, they need to be slightly wider.  I have verified this multiple times by designing a part in SolidWorks with a 0.4mm wall, exporting it to Cura as an STL, and previewing the slices (using a 0.4 mm nozzle size).  If I increase the wall thickness in the model to 0.41mm, Cura will slice the wall.  This seems to suggest to me that Cura does account for a deposited line width > nozzle diameter.  It calls to question whether the shell thickness is actually a physical dimension for the 3D print or just a parameter for the slicer engine.  I have taken it to mean the number of passes around the perimeter in units of nozzle size, similar to other slicers that ask for a shell count.

Thanks in advance to anyone who has put in the time to read this post and kindly share some knowledge.

EDIT 1: My interchanging of terms "width" and "thickness" made it sound like I'm referring to z-layer height.  Also, Trish pointed out that "line width" is the better term rather than "layer width" so I have updated this.  My post is only concerned with the deposited layer width in the x-y plane--"line width".

So, I think I may have found a satisfactory answer. Cura 3.6 includes separate parameters for line width and shell count:

This seems to decouple the line width from the specified nozzle size and target what I believe is a more optimal width (~110% the nozzle diameter).  It was the other version of Cura that was driving a lot of confusion with the line width being defined by the nozzle size.  This also removes the weirdness of not being able slice lines equal to the line width.

Thanks to all who responded.


How does G-code for belt bed printers work? Are there any good resources on understanding how G-code/slicing for belt bed printers works? I'm told the upcoming Creality 3DPrintMill is being used with Blackbelt Cura, which seems to be a fork of a really old Cura modified in some way for belt bed printers, but I didn't find much information on how it actually works.
In particular, do these printers use normal gcode? What is the coordinate system like? Conceptually the axes are not orthogonal but skew (e.g. 45°) to the belt axis, and part of my question is whether the coordinate system is in this skew basis, or somehow transformed in firmware to an orthogonal basis.
In asking this, I'm partly aiming to determine how hard it would be to use existing/unmodified software (e.g. upstream Cura) to slice for such a machine, possibly with postprocessing of the gcode.

Belt printers use existing 3d printer hardware, including controllers and steppers. The Z axis is tilted at 45 degrees (usually). So to answer the first part of your question: yes, you can use G-Code to control the printer, just as you would with an upright printer.
I don't know a good resource that describes everything, but I will try my best here: it's not enough to just skew everything. Basically, you need to rotate all you models at 45 degrees along the x axis, using an imaginary 45 degree plane as the "build plate". Then, the model needs to be skewed, so that everything that would otherwise be on the build plate is now at y=0. Z needs to be scaled by sqrt(2) to make up for the diagonal belt. The result should be a working G-Code.
But if that's not enough, the issues are in the details. Supports will not work as expected at all. Supports in positive y need to start at 0 degrees, whereas in negative y, you need no support at all. Rafts need to be placed quite counterintuitively on zero y instead of zero x. And giving the build plate/belt a different extrusion temperature is also difficult, because every build plane touches the belt at some point unless it is a bridge. Oh, yeah, and bridges work perpendicular to the build plate instead of parallel to it.
So, yeah, it's not easy at all to generate good G-Code for a belt printer.


Filament gets coiled inside the extruder A while ago bought a Bowden extruder to replace the old built-in one (It was malfunctioning or something that I cannot remember well). This one in particular has been acquired:

The thing is, that almost a year has passed since the printer did something rather than getting jammed and not work properly. The extruder itself seems to work properly, when I heats up and push the filament by hand seems to pass properly.

When assembled and start to print, the printer at first seems to work, but after a minute or so, it stops extruding (gets jammed or something).

The last time that I removed the filament and I've found out that it was coiled inside (Very strange):

My first thought was that the filament was thinner than the extruder's specs, but the seller says that is for 1.75mm, and all my filaments have that diameter.

What I am missing? Something maybe that is not properly mounted?

The product is not official, bought on Amazon (I didn't know about e3d v6).

Printing temperature should be 180ºC but I've seen now that Cura sets the first layers to print at 200ºC. Material: PLA

My printer is a BQ Prusa i3 Hephestos.

As long as there is no more information about the printer itself (I searched a bit and around half of buyers were severely unhappy with the result), I'd advise you to make a full check of all of the important parts that make up a 3D printer making ok prints:

Are motors moving as they should?
Is the extruder actually extrude filament when told so (do the check "2cm" = 2cm extruded)?
Is the Z calibration ok (<- VERY important, will make tons of weird problems if extruder is too close to the bed, believe me, don't skip out on this one. A blue tape or not a blue tape makes a world of difference).

Also of course check your filament (no variations too big of the diameter).

For the temperature, IMO go for the higher for starters (maybe no, see "heat creep" below), you won't be able to bridge / less good quality etc. but you'll get pieces done.

NOW, the image you posted shows a twisted (I don't know how to handle that) or a grinded filament.

When I say 'grinded' I mean that the filament got stuck somewhere (see below) and the (cogged) wheel pushing the filament is so strong that is grinds off plastic from it, forming waves on the filament. Eating away parts so it looks like your photo.

If that's the case, then you should check out "heat creep", it's basically the heat in the lowest part of the extruder (the thing you call a bowden extruder) will heat up the filament and make it melt Above the heat block, making a blob of half melt plastic stopping the forward movement of the filament.
This is usually mitigated by two things, that lacks more or less in cheap chinese knock offs:
* The fan and it's cooling efficiency (the fan must blow when the heat block is hot, even if there is no printing going on. Even if the heat block is no longer heating. I shut the fan off at around 60°C).
* The Heat break: if it's heavy it will conduct too much heat, if it's thin it might work but will break easily.

3D Printing is not obvious or easy, but spend some time and it'll start to work well!

Cheers


Anycubic i3 MEGA not heating past 140 ºC [SOLVED] on [EDIT 3]
I just finished changing my i3 Mega's PTFE tube and brass nozzle, reassembled it, always taking care not to damage the heating element and thermistor wires.
Then I check the temperature and it was cooling down, despite the set temperature being higher (210 ºC). I turned it off, let it cool down and turned it back on. I set it again to 210 ºC and it only reaches about 135 ºC-140 ºC, not going over it.
So I change the heating element and thermistor for fresh new ones (original ones, that came with the printer) and the same behavior takes place: not heating up beyond 140 ºC.
Any ideas on why this is happening or how to fix it? I checked the connectors and they all seem to be fine. Cooling fans run normally as well.
Printer: Anycubic i3 MEGA. All stock parts, except the new nozzle (standard brass nozzle) and the PTFE tube (a blue one with 1.9 mm internal diameter). I'm setting the temperatures through the printer's interface, as I have always done.
[EDIT]
I did check some stuff with the multimeter and what I got is that:

The cables leading to the print head are fine;
The heating element's voltage is correct and the MOSFET seems to be
working fine both by checking the voltage and from the LED that
lights up when it is sending current to the HE;
The resistance of the HE is correct as well;

Form that, I am guessing the problem is the current fed to the HE. Later today I will try to heat both the nozzle and the bed to the (safe) max temperatures and see if the bed heating is problematic too. If so, the problem should be related to current.
If anyone has any other ideas, they are appreciated! :)
[EDIT2]
Heating up the print bed and the hotend at the same time didn't affect the bed at all. It heated up at the same pace as usual. Since the cables are fine, it shouldn't be a problem related to the power supply.
So I'm gessing the problem is the motherboard (Trigorilla 1.1). It didn't seem to have any burned components at a glance but I'm gonna check with a multimeter.
[EDIT3]
Turns out I messed up the heatbreaker, so the heatsink was cooling the hotend way too much... This is one way of learning I need to be careful with the heatbreaker, I guess. I'll leave a solution here for the newbies like me that end up in a similar situation.

I recently had similar problem with my Prusa i3 MK2.5. It was not able to maintain the set tempereature. I measured the heater catridge (which was new) and its resistance was correct (about 4 ohms). So I changed the hotend MOSFET on the stock board with no result. So I changed the heater catridge for the older one and the issue was gone.
Since you have changed the heater, it is unlikely that you have multiple bad ones. Thus the only thing that remains is the MOSFET and the power supply. Make sure your power supply is stable under load and can deliver enough current.
More likely it is the MOSFET. It behaves like a resistor in the path for the current. If it is swithced off, it is like a large resistor (units or tens of megaohms) in series therefore no or very little current can flow. If it is switched on (units or tens of milliohms) the resistance is very small allowing the current to flow through the heater. If a MOSFET is bad, when it is switched on it can have higher resistance (units of ohms) and thus limiting the current and creating a voltage divider. Which you can measure.
You have to get to the bare wires that lead to the heater. Turn on the heater. Place your voltmeter lead on one wire and the other lead on the otehr wire. The voltemeter should show voltage close to your power supply voltage. If it is showing less, the MOSFET is bad and needs replacing.
For that you will need soldering tools and skills. You probably have an SMD MOSFET soldered directly to the board. I suggest removing it and replacing it with a THT MOSFET that you would place separately from the board with its own heatsink. When on the board, the board acts as a heatsink.
If you cannot do that yourself, ask someone to do it for you.
Before replacing the MOSFET, find whether it is a n-channel or p-channel MOSFET. It will most likely be an n-channel MOSFET but make sure it is.
If you replace it with THT MOSFET I would suggest these two: IRFZ44N (n-channel) or IRF4905 (p-channel). They are general purpose MOSFETs and should work well enough for drop-in replacement.
If it is not the MOSFET, power supply or the heater, then I have no idea.
You should be able to trace one of these loops:
power supply -> (fuse ->) heater -> n-channel MOSFET -> power supply
power supply -> (fuse ->) p-channel MOSFET -> heater -> power supply
Most likely will be the first loop.
NOTE: Checking the heater resistance might help but does not have to. At room temperature the resistance might be within limits (as with mine example) and when heated up the resistance increases with temperature and thus limiting the current. You would have to measure the resistance when heated up and disconnected from all circuits. (Heat up -> disconnect heater -> measure -> cooldown).
Hope that helps and good luck.


Printing straight from the browser Are there any browser extensions or printers with OctoPrint built in that would allow me to print straight from the browser?
Thinking of a workflow like this:

Make something with Tinkercad (or other online service)
download stl or obj
select print from bookmark or dropdown menu
print is sent to printer and starts printing

There was the CuraEngine plugin, but it's not really maintained anymore. It should still work though


What's so special about cleaning filament? What is different about cleaning filament to make it effective? What is it made out of? How does it work?

You may discover that "cleaning filament" is also described as nylon filament. Nylon requires higher temperatures than most commonly used filaments. As you raise the hot end to the required temperature to melt the nylon (typically 250°C, all of the other debris has either carbonized or melted.

The hot end is allowed to cool (30-50°C) at which point the nylon filament is pulled out in the reverse direction. Some 'net references suggest a hard pull, but I disagree with violent mechanical forces being applied to delicate mechanical devices. Perhaps that's why my cleaning process takes two to four attempts. Some net references also suggest to start the nozzle heating after reaching the cooling point and to begin applying force upward during the re-heating.

My Sigma 16 uses the above method and also suggests a "strong pull" which is a translation from "sharp yank," in my opinion.

This will collect the debris from the nozzle and heat break and may completely clean the filament path.

I use "natural" clear nylon for cleaning and perform the sequence two to three times, until the heated portion of the nylon no longer has contamination visible.

Even nylon filament that is not dry enough for printing works for cleaning. The moisture bubbles turn the filament into flimsy punctured nylon thread, but it causes no problem with the cleaning process.

FilamentOne website references most of what I've posted.

The above image resembles my experience, although the severely "dirty" image is much more excessive than my cleanings. The worst is to have PVA support material that has been "cooked" at ABS temperatures or higher for long periods. An almost guaranteed nozzle clog is the result of those conditions.


A free simulation program With some of the items I am designing I would love to put them through a simulation. Like crushing, for example. I want to know how well my object can handle any situation I put it through so I can make changes before I print out the object, only to find out there was a weak spot.
I have been trying to learn ParaView but it is a little complicated off the bat, I would like something easy to use.
If anybody knows of a program that would be fantastic!

Fusion 360 will do finite element analysis (simulation), although I haven't used it. Whether it will perform the type of analysis that you are looking for, I do not know. Check Autodesk's tutorials.

One problem that you will encounter is that items printed using FDM technology are highly anisotropic. In other words, they have a grain, and are stronger/weaker in some directions than in others. I do not think that Fusion 360 can take account of that in its analysis.

Autodesk: Fusion 360


Combining multiple STL files I have a collection of STL files, each containing a separate moving part of an object I want to print. (Imagine a set of gears, or similar, that prints as a single object with multiple moving parts.)

My plan was to import them all into Cura, then hit print, then take my fully assembled object off the build plate. However, Cura ignores the coordinate system in the STL files and automatically separates the components from each other on the build plate. This is usually helpful, but it isn't what I want in this case.

So I'm looking for a quick and simple way to combine my multiple STL files into a single STL file. I know that the objects don't overlap, so I don't need to do a CSG union operation - it's enough just to concatenate the objects.

I tried OpenSCAD, which works, but it takes a really long time, because the meshes are fairly complex and it does the full Boolean operation. Is there another quick and simple way to perform this task?

I'd prefer a command line utility, but I'd also be happy if there's a quick and simple way to do it in some free graphical software. (However, I don't want to spend time manually positioning the objects - they're already in the right places in the STL files, so I just want to import them and go.)

Edit I've accepted Trish's answer (use Blender), but I'd still appreciate a command-line option if anyone knows one.

The operation you want is almost just cat'ing the files together. However you need to remove the 80 byte header from all but the first, and add up the 32-bit triangle count from each file immediately after that. Output should be:

Copy of first 80 bytes of file 1
Sum of int32 from offset 80 of each file.
Bytes 84-end from each file.

See https://en.m.wikipedia.org/wiki/STL_(file_format)


I am getting bubbles and a bulge at the bottom layer of my 3D print I am printing ABS on an Ender 3 printer at a temperature of 240 °C on the nozzle and 110 °C on the bed. I am getting the following result:

Is there any way I can fix this?

I think that your bed is too hot because the bubbling is only on the bottom layer, if it was through out the entire print, I would say that it is your nozzle temp and you should do a temp tower, but because that isn't the case try lowering your bed temp


Prusa i3 - First layer does not stick and looks jagged My first layer is suddenly not sticking for every new print I'm trying. When it lays down the first layer it has this weird jaggedness to it, doesn't firmly stick to the plate, and gets dragged by the nozzle. I've printed previously successful prints without an issue, but any new print I export from Cura is having this issue. I'm using the same profile that I do for the previously successful ones.

My relevant print settings are:

Material: PLA
Layer height: .2mm
Hotend: 205c
Plate: 60c
Fan cooling: 50%
Speed: 60mm/s

Your nozzle is too far from the build plate. You should make some changes to bring the nozzle closer to the build plate for the first layer. There are a number of possibilities for doing this:

Adjust the Z-axis endstop
Loosen the bed leveling screws
Add an offset in G-code

This will squish the plastic down more, enabling it to stick to the build plate.

With solution (3), you have to be careful that you don't crash into the endstop. This solution works best if your printer homes towards max (and not min) or if you have non-mechanical (hall or optical) endstops.


how to control fine details from overhanging part to not build upwards I noticed that when printing small teeth on a pulley that the angle is not matching the design angle. I am printing without any support structure.
Overview:

Detail:

Printed:

The printed overhang incline angle under the tooth looks good (maybe not quite steep enough;) but the top angle of the reclining section looks too flat. It is as if the tooth is too perky.
(I have observed a similar behavior when printing overhanging corners. They build upward more quickly.)
What is causing this, and how to prevent it?
I reduced the speed for the outer layer to 30 mm/s, the infill is set to 40 mm/s. Layer (Z) is set to 0.1 mm. Material PLA 1.75 mm, nozzle 0.4 mm.
Cura layer detail:

Cura Prepare

Cura Preview

I think the issue is unsupported overhangs. There is not enough material to support the first layer of each small tooth. Have a look at how your slicer slices the first couple layers at the bottom. It might be that it tries to reduce the angle to 45°, so that it can print overhangs, or the overhangs are drooping before the next layer can assist with support.
Looking at your first two images, I think the printed top part of the tooth is actually quite similar to your 3D design.
You can fix this by making the tooth profile from the side have a 45° slope to maximum height, and the same on the top if you want the teeth to appear symmetrical.


How to Make Use of 3mm Filaments? I'm not really sure if I'm asking the right question here, but I just made a noob mistake of buying 3 mm filaments instead of 1.75 mm. I have a Makerbot Replicator 2 which I've been using and so far it is pulling in 1.75 mm quite well.

Is there any way I can still make use the 3mm filaments, or do I need to use the filaments on different models? If it is the latter, which particular model is able to pull in 3 mm filament well?

This is not a definitive answer (and has turned into a ramble), as I have not yet had to change my filament size.

However, initially, I would have thought that only the hotend and the hotend's nozzle would need to be changed, from one that can handle the 1.75 mm filament to 3 mm. If the extruder is spring loaded, then it should adjust itself to the thicker filament, without a problem. If not, then you may have to do a slight manual adjustment.

However, after doing some further reading, there may be other factors that need to be considered, such as:

Extruder gearing;
Melt time (which would imply a different feed rate)

It could be worth having a close look at the aperture of your hotend. If, in the unlikely situation, it looks as if the hotend would accept 3 mm (or if you could remove the lining so that it can), you may not need to actually change any hardware, but instead just try tweeking the feedrate in the software, because as your nozzle is less than the width of the filament anyway, then it will be fine for both 1.75 mm and 3 mm. A 3 mm filament would require more heating, and therefore a slower feedrate than a 1.75 mm feedrate. Once the filament has melted, so long as the pressure from the extruder is sufficient, then the molten filament should come out of the nozzle. However, this may be a less than satisafctory method and result in some dubious prints.

There is an interesting thread on the RepRap wiki, 1.75mm Filament vs 3mm Filament, that discusses most of the points above.

It should be noted that the advantages of 3 mm filament has over 1.75 mm are that it is:

cheaper
stiffer (less flexible) and thus "easier" to push through the hotend.

As an aside, one interesting point raised in the thread, is that maybe a smaller extruder can be used, for the narrower 1.75 mm filament, thus resulting in a lighter print head. I am not sure how true that is.

This article, Converting a 3D printer from 3mm to 1.75mm, does the reverse of what you want, and comes with a video. It states that, as you have already found, that the hotend needs to be changed:

  The printer [Thomas] is changing out to accept 1.75mm is the Lulzbot
  Mini, one of the most popular printers that would ever need this
  modification. The only required materials is a new hot end suitable
  for 1.75mm filament, a 4mm drill, and a few wrenches and allen keys.
  It would be a smart idea to get a hot end that uses the same
  thermistor as the old one, but that’s not a deal-breaker as the
  problem can be fixed in the firmware.

Alternatively, you could leave your printer as it is and use a 3mm to 1.75mm filament converter, which may be a bit of overkill for just one reel of filament1.

The bottomline

To be honest, is it worth the hassle, time and expense of having to modify and re-calibrate your printer (or worst case, change the model of the printer), just for the price of a reel of filament (assuming that you did not bulk purchase a bunch of reels)? It may be better to stick to one filament size (i.e. your original size) for all of your projects, and so resell the reel of 3 mm and stick with the 1.75 mm printer and buy the correct filament2.

1 See also Conversion of 3mm ABS filament to 1.75mm

2 See also Tom's answer to Conversion of 3mm ABS filament to 1.75mm

See also Can 1.75mm filament be used in a printer that takes 3mm filament?