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How to control 4 thermistors in a heated bed?
My print area is ~ 17x16 inches (431.8 mm x 406.4 mm = 175,158.4 mm/2). To that end I need four (4) 200mm square heaters, and associated mosfets to run it. Each heater has it's own thermistor and can potentially reach the target temp independently (theoretically they could, since there will be deviations in manufacturing).
My mainboard (the SKR Pro) has support for 4 thermistors; however my solution in this configuration has 5.
When I double the size of the printer later this year, I expect that I will need 8 heaters.
Is there a solution to control that many heaters such that non of them over shoot their temps, or am I going to have to design and build a dedicated thermal management board to control beds of this nature?

As far as I know it hasn't been implemented in Marlin, but there is this issue tracker that says it is fairly simple to implement. Alternatively (since you need more than 2 zones), you could use an Arduino Uno to communicate with the SKR and let the Uno handle the individual heating of sub beds. E.g. return the average temperature of the 4 beds, or the lowest temperature etc. It would be a cost saving if the Uno is able to enable beds or not, for small prints, you could use the e.g. left front heater!

You can use the Klipper firmware which accepts an arbitrary number of heaters.
Then you can write a Klipper macro which takes one input and applies it to each heated bed (or not, as you prefer).
With Klipper you can also add another Arduino and connect it to klipper as well, in case you don't have enough pins on your board: klipper is not limited to controlling one single board per printer.
Check the docs.

Therefore Klipper can operate across different µControllers by design?

Yes. For example, my 3d printer board has soldered drivers. I want to add Trinamic drivers, but I cannot fit enough due to lack of pins. I can connect a simple Arduino Nano (5 euro?) to the Raspberry Pi in addition to my board, connect the TMC to the Nano, and Klipper will control both at the same time.

Added link to multi-mcu configuration.


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How to prevent model from peeling off of resin printer buildplate during print?
Recently I have started using a fairly large LCD resin printer. (Yidimu Falcon Pro)
It has a fairly large 260x160mm perforated and coated steel build plate and a decent dual rail Z axis with a ballscrew. It has a 10" LCD. It prints ChiTuBox files from a USB stick.
I have been having a mostly successful print, at good quality, but the bed adhesion keeps haunting me. The best print on this machine had parts curling up from the build plate, however most of the print succeeded.

Two times I have had a very well adhering raft, however delamination occured directly after the raft.
Usually the left side lifts from the bed while the model stays on the build plate.

I have tried:
Changing resin (tried Druckwerk Pro D Black and Anycubic Black)

Decreasing lift speed
Increasing lift distance
Increasing bottom layer exposure time (from 60 to 180, as suggested by Druckwerck supplier)
Increasing bottom layer count to 9
Using a large raft
Using a very large raft
Using a very small raft
Leveling build plate without vat in place, using paper
Leveling build plate while keeping vat in place

What would be a good next troubleshooting step?

Are you sure the room temperature is not too low?

looks like you have done a lot of work to try to get it working.
considering you are having issues on one side of the build plate my thought is that it is a levelling issue or an issue with the plate itself. Try levelling it using the video "Getting Started: Leveling the Build Plate" it's for a different printer but pay attention to the part where he goes over making sure the left and right sides are level and how to check that. I had a problem like yours, and the issue was that as I tightened the screw to keep the build plate in the levelled position I ended up causing it to move. I made the same mistake a few times before realizing that I was messing it up the same way every time because I'm right-handed. after realizing that it was easier to fix.
If the issue is the build plate it's self it may be a matter of it not being flat (unlikely), Or not providing a good bonding surface. if the latter I suggest you do some research and decide for yourself as there are a lot of dividing views on how to fix that issue.
It also looks like you are having issues with the print after the bottom layers. It could be caused but the separation issue but it could be that you just need to increase your exposure time for your non-bottom layers

It was indeed found that my plate was not level. The manufscturer shipped a new plate, the issues did however not go away. I will try your advice regarding tightening of the screws and such.. If that does not work, I will try different resin (Sirayatech).

I had an issue with my Vat Bolts, one being cracked and leveling at a greater tension than the other.  With the compressible feet of my Vat this caused a problem in the FEP.  This was enough to cause failure on one side more than the other.  Cause was verified by switching the left and right knobs, thus shifting the failures to the opposite side of the print.
Just a thought.

Did you mean "this caused a shift in the FEP"?

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Deactivate combing in first layer
I noticed a problem with the combing feature. When I print the first layer with combing set to “not in skin” the extruder does not retract on the first layer. That leads to ugly oozing strings in the visible parts of the prints and also to other problems. E.g. if I want to print a model with tiny circles in the first layer (like for screw holes) the circles get easily pulled away because the extruder is not retracting. At first I thought I’m having sticking problems with the first layer, but I improved that a lot and my prints are perfectly fine now, when I turn off combing completely. In that case the extruder is retracting as desired and the circles stay in place. But turning combing off isn’t always a good option. Sometimes large prints take so much longer and may even have little marks in the visible surfaces where the retractions happened. So I don’t want to turn combing off completely just to be sure the first layer is okay. I saw this behavior with a lot of different models now, so I’m sure, Cura doesn’t always handle the first layer as skin. Setting combing to “not in skin” does definitely not help.
Here are two pictures of the first layer of a print. The first one with combing turned off. You can see the light blue travel lines which mean, the extruder is retracted.

And the second one with combing set to “not in skin” where you can see the dark blue lines. The extruder is not retracted there which produces the described problems.

Updated question to answer:
Thanks a lot for explaining that to me. But I’m afraid the problem still persists. The value of “retraction minimum travel” was at 0.8 mm, which should be fine I assume. Now I’ve set it to zero, just to be sure. The extruder does still not retract as you can see in the picture below.

But when I turn combing off completely, the retraction is happening. So I think it is a problem with the definition of “skin” for the combing mode “not in skin”. The bottom layer doesn’t seem to be treated as skin. By the way, I’m running the latest version of Cura of course (4.6.1).

If you set it to Not in Skin it will not comb and as such it will retract. Retraction travel moves are shown as light blue lines

Light blue are retraction moves.  Dark blue are non-retracting moves.  Both types are non-extruding moves.

In that respect you would expect that if you set Combing to Not in Skin, it will retract and move to the other position:

If you wouldn't comb at all, you would see the same:

If you would comb all layers, so no retractions, we would expect dark blue lines:

Basically, Cura does exactly what it needs to do as seen in the screenshots, I cannot place/reproduce the screenshots in the question. To explain this (as commented below by @R..) another setting or settings may have caused preventing retraction like the Retraction Minimum Travel (retract_min_travel) in Cura.

It's possible there's a bad non-default setting for max travel distance without retraction in OP's config. Just looked it up and that setting is called Retraction Minimum Travel (retract_min_travel) in Cura.

@R..GitHubSTOPHELPINGICE That could be a perfect rational explanation!

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Calculating gear ratio for leadscrew
My calibration at my printer is okay. When I try to move 10 mm, it's exactly 10 mm.
But I want to know what is my precision for Z-axis.
(not posting the link of the product maybe it's not okay for the platform)
Spec for leadscrew:

Lead screw diameter: 8 mm
Screw pitch: 2 mm
Lead of thread: 8 mm

My question; is my gear ratio 4:1 or 1:4? It's giving different results.

This answer gives insight in leadscrews.

In my experience, with decent stepper drivers (e.g. A4988), sticking to full steps for Z axis does not seem to be important (doesn't seem to make any difference to print quality).

My question is not just for 3D printers, I'm thinking about modifying to high precision CNC :) Thanks in advance

In short: It's 1:1, and your "pitch" for that calculator is 8 mm. Pitch and lead are frequently confused.

Your lead screw nut advances 8 mm every complete rotation of 200 full steps, so a single full step would change the height by 8/200 = 0.04 mm. This implies you need to set the layer height a multiple of 0.04 mm.
The gear ratio of 4:1 (a reduction) is required to get to your desired 0.01 mm layer height, but that is a very uncommon and a too small layer height to use.


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What are pros and cons of piezo Vs strain gauges bed leveling sensors?
I'm designing a dual hotend carriage for a HEVO printer that will run in an enclosed heated chamber and I'm evaluating which bed leveling sensor I should use.
I read that BLTouch and similar sensors stop working in a hot environment, and likewise, capacitive and inductive sensors are affected significantly. Piezo and strain gauges (force-sensitive resistors) are my choices.
What are the differences in practice? Both related to the heated chamber (70+ °C) and in general at room temperature.


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Causes of over-extrusion?
What could be the causes of a consistent over-extrusion? I know about these:

steps/mm of extruder motor set too high
larger filament diameter
slicer setting: filament diameter - setting it lower makes the printer extrude more filament
slicer setting: extrusion multiplier - setting it higher makes the printer extrude more filament
unlikely but possible bug in slicer or in printer firmware
other: low/high tempereture, too much/little tension on the extruder gears, wrong nozzle fitted,...

Now to my problem. I had to replace the entire hotend assembly on my Prusa i3 MK2,5. Before that, there was no issue. After the replacement and after noticing the issue, I followed the list above. I recalibrated the extruder and in fact I had to increase the steps/mm to match the extruded length.
I have printed with different filaments and the issue is still present. Also I checked the diameter of all the filaments which are quite consistent (1,75 +-0,3 measured, 1,75 +- 0,5 given by the manufacturer). All of them were the same brand.
I also checked slicer settings and the default values that I used before were still there.
Slicer and firmware versions are the same as before the issue started occuring.
I use the same print settings as before and have checked the extruder gears tensioner multiple times over. The nozzle came with the hotend and according to the E3D dots it is in fact the default 0,4 mm nozzle. However, I cannot check the real diameter.
I know I can solve this issue by altering the steps/mm or extrusion multiplier because the over-extrusion is consistent. I want to know if there is something I am missing that could cause this.
Thank you for your valuable time and suggestions.
Edit:

Did you ever find a solution to this?

No. I have once again tried recalibrating the extruder, this time I decreased steps/mm. As you have said, it is minor overextrusion so I might just roll with it.

This is almost surely the source of your problem:

I had to replace the entire hotend assembly on my Prusa i3 MK2,5. Before that, there was no issue. After the replacement and after noticing the issue, I followed the list above. I recalibrated the extruder and in fact I had to increase the steps/mm to match the extruded length.

There is no plausible physical reason for extruder steps/mm to change due to replacement of the hotend. Steps/mm is purely a function of stepper motor steps per rotation and extruder gear radius. Set it back to its original value.
If the extruded length is not matching what it should, you have a problem with blockage/flow rate in the hotend restricting advance of the filament and causing the extruder gear to grind without moving it, or the motor to skip steps. Adjusting steps/mm to "compensate" will not fix this; it will just grind/skip more. Instead go back to the beginning, with steps/mm set correctly to the original value, and start looking for the cause of your hotend problem.

I have disassembled and reassemled the assembly, recalibrated the extruder and still nothing. Also, your answer does not make any sense when talking about over-extrusion (it would make a lot of sense when talking about under-extrusion). A blockage in the filament path cannot increase the flow of the plastic consistently. It can do it repeatedly: pressure builds up in the fillament because of a blockage, when the pressure is large enough, the filament gets released, therefore momentarily increasing the flow of the material. But that is not what I am experiencing. My over-extrusion is consistent

@MStarha: The overextrusion happened even before you made any adjustment to the steps-per-mm? You said you increased the steps/mm which absolutely would cause overextrusion.

Yes, it happened before the first extruder adjustment and after the hotend change. That's the problem, it was over-extruding even when in fact the extruded length was shorter than requested.

What you're describing is physically impossible (less length at same diameter but more volume). Are you sure what you're seeing is overextrusion? Can you provide some pics?

Added pictures to the original post. I know it is not logical, thats why I am here. Cannot figure it out myself. The over-extrusion is subtle, but it is there. As long as it is there, I cant trust the dimensional accuracy.

Are those with steps/mm reverted to original setting? Or increased?

I have not written down the original steps/mm. This is after all changes (first change of step/mm, dissassembly, reassembly, second calibration). It is what I have now.

What is the value you have now? Can you not do a factory reset? The E steps per mm should be equal to (assuming a 1.8°/step motor and 16 microsteps) 3200/(pi*d) where d is the diameter of the gear.

The steps/mm value is 152,6. I might try a full reset, but if the end effect is only reduced steps/mm to compensate for over-extrusion, then I can set it manually.

From the photo it looks like you have some fairly minor overextrusion and possibly a misleveled bed making it looks more severe on the bottom surface. If you're going to "set it manually", at least figure out first what the ideal value should be, based on the gear diameter, so that you know if your new empirically calibrated setting is theoretically over-extruding or under-extruding.

I will try to compensate for it with steps/mm then as there does not seem to be a problem with anything else. The issue with theoretical calibration is that you cannot measure the diameter of the gear since the teeth bite into the material. How much they sink in depends mostly on the material and the tension. I did a quick check and based on the step/mm value, the diameter would be ~6,6mm, which is possible. But anyways, thank you very much for your help. I will post an update.

The gear should have a data sheet giving you an accurate measurement. And if it needs compensation for biting into filament, that's per-material so should probably be modelled in your slicer's material settings not changing esteps.


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Different Probe Z offset for G28 and G29
After trying to solve this for the whole weekend I've run out of ideas.
I've fitted an BLTouch to my Ender-3 with an SKR mini e3 V2.0 board, firmware is Marlin 2.0.
My issue is the following:
when I do autohome (G28) it uses the Z-Probe (BLTouch) to home (this is expected).
I then set Z Probe offset to 0 (using M851 Z0) and move Z down until it the nozzle touches a piece of paper.
I then set the Probe Z offset to whatever value Z is at (M851 Z-4.10), save the settings to EEPROM and restart the machine. When doing another G28 and moving Z to 0 afterwards the distance is perfectly the same. This is repeatable.
However when I do G29 it measures the bed to be sitting around -1.9 mm, therefore moving Z to 0 will crash the nozzle to the bed. I can change my Probe Z offset have this fitting (M851 Z-2.20), however then the nozzle sits ~2 mm above the bed when doing another G28 with "Bed Leveling" disabled.
All of this is perfectly repeatable, so I think my I've got something off in my Marlin configuration, but can't find anything wrong.
What I've tried so far:

Setting the Z offset as default in config -> this yields the same result as saving it to EEPROM
Reflashing the firmware and resetting the EEPROM -> this didn't change anything
Connecting the probe as Z-Endstop and as Z-Probe -> after matching the configuration (setting/unsetting Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN) it just gave the same result.

Did anyone encounter this issue before or can give me any idea how to fix this? Any help would be appreciated.
EDIT: I've just flashed the precompiled stock firmware from the BTT Github and it works. So im quite sure i've got something wrong in my config. But since I can't find the configuration.h for that .bin file, I can't realy compare both

Hi welcome to 3DPrinting.SE! Just out of curiosity, how did you define NOZZLE_TO_PROBE_OFFSET? Note that you need to  autohome G28 after you set M851 Z0.

I've tried using #define NOZZLE_TO_PROBE_OFFSET { -42, -6, 0 }, and #define NOZZLE_TO_PROBE_OFFSET { -42, -6, -2.20 } but this value should be overwritten with M851 right?

For your information, if you don't use @[username] the commenter doesn't get pinged. Comments under the question will always ping the question owner!

Better to leave the Z offset to 0, then there is no question whether is is overwritten or not. Note that -1.9 - 2.2 equals -4.1, so this might be the cause. Furthermore, a BLTouch doesn't need to have such a large offset, you can place the sensor a little higher. My values are in between 1 - 2 mm. Please add a photo of the sensor in relation to the nozzle.

@0scar thanks for your help, I finally figured it out. The issue was that i set Z_MIN_POS to -2 to be able to measure the offset. (I believe having read doing that somewhere, but cant find it now) after setting that back to 0 and it works now. I guess that the 2mm were added somehow, but I can't understand how that this is expected behavior.

I'm answering my own question here.
The Issue was that I set Z_MIN_POS to -2.0 I guess these 2 mm were subtracted from G28 but not from G29.
I don't know wether this is expected behaviour but changing Z_MIN_POS back to 0 fixed the issue for me.


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Pretty ugly surface remains after using support ramp. Are my slicer settings correct?
I'm printing a object with a pretty sizable overhang.  And the results, after support removal, are pretty ugly.
Here is the print before support removal.

And here is the final product, sigh.

Finally here are my slic3r settings:

Generate Support Material: [✔]
Overhang threshold: 60°
Max Layer Count for Supports: 0 layers
Enforce Support for the First: 0 layers
Raft layers: 0 layers

Options for support material and raft

Contact Z distance: 0.2 mm (detachable)
Pattern: pillars
Pattern spacing:  2.5 mm
Pattern angle: 0°
Interface Layers: 3 layers
Interface pattern spacing: 2 mm
Support on Build Plate Only: [✔]
Don't support bridges: [ ]

The material I'm using is ABS, 230 °C temperature setting.  Layers, Adaptive Slicing, Adaptive quality: 75 %, Match horizontal surfaces.  Vertical shells, 3 perimeters minimum. Horizontal shells, solid layers: top: 3, bottom 3.
Is there a way to improve this?
Note: for anybody interested... these are small disposable spatulas used to place bondo mix onto a flat surface at the bottom of a restricted space, to fill small holes in wood. Its too tight in there to use a normal putty knife.

Some more print settings
Included here are the speed settings from Slic3r:

G-code analysis

I'm wondering why there is such a large gap between the gold colored E shaped interface to the blue spatula handle?  And that makes me wonder, what support material and raft settings should I be using?  Why is that gap so big?  (And I have to go back into SolidWorks and check, but I'm nearly certain that handle is 2 mm wide. That gap to the support is really big.)

It appears as if the support is just too far away, and then the bridging fails as of the high print temperature and minimal amount of cooling. This prints much easier in PLA.

Judging from the print quality of support material (very "fat") and of top surfaces (which look with ripples and a lot of material), you have at least 3% overxtrusion, which will result also in stronger connection between support and print, and more difficult removal, lower quality parts.
I would reduce extrusion by 3%, to start, and see if it goes better. In your case you can tolerate underextrusion, since the part is likely not stressed significantly, so in doubt reduce it even more.
You can also print this test part to check optimal extrusion.
Also, remember that extrusion is (almost always) dependent on speed: if you get perfect extrusion at 60 mm/s, infill at 80 mm/s will be slightly underextruded and outer perimeters (30 mm/s) will be overextruded. In general, set everything to the same speed.

I'm not terribly familiar with slic3r, but it looks like you have a setting (possibly a default one) to slow down on printing overhangs. This was a popular "feature" in slicing software (Cura has it I know) but it's exactly the opposite of what you should be doing. When slowing down to print an overhang, the pressure in the nozzle forces the material to keep coming out at the same rate it was coming out until it subsides, and you end up with a big hanging glob of ooze like in your photo.
If your printer firmware has linear-advance/pressure-advance functionality, this can mostly be eliminated. But if not (most stock firmware), you need to maintain full speed on overhangs, and might even need to turn up your acceleration limits so that you don't get a significant slowdown just by decelerating to go around the corner.

I see your words written here, but I don't understand what you are talking about.  "Slow down on printing overhangs" ?  Where is that set?  You mentioned Cura, does that mean Slic3r has a similar setting (and fix)?     Then you jump to firmware.  I'm using Slic3r --> Printer Settings --> General --> Firmware, G-Code Flavor: Sailfish Makerbot  Can that setting be corrected in Sailfish?  many thx.

Hmm, I thought slic3r had an option like this but I can't find documentation on it. Can you open up your gcode in a viewer that shows speeds and see if it's using a lower speed for the overhang? If not, it may be just an acceleration issue.

I'm trying.  Based on your comments I created vebose G-Code.  I'm playing with https://ncviewer.com/ but there is too much stuff in the way to see the specific g codes at the interface between the overhang on the desired part and the support.  Note, I do see varying F codes (which I believe affects the speed of the head)  and E codes (extrude commands)  Do you have a suggested G-Code analysis system that would make this easier?  Hmmm. Let me add my GCode to the problem statement.  oops. no go on file upload, sigh.

@zipzit: I like https://www.gcodeanalyser.com/ and http://gcode.ws/

See edit #2. I'm wondering if print speed really is a root cause here.


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weird part slices with horizontally printed holes
I just made a remix of that mod to have a more rigid chassis for Z axis.
While the parts are a little too heavy to my taste, I did import the STL to FreeCAD and made some adjustments before printing. I noticed weird defects on the layers in the range of a hole. It seems that all the layers belonging to a hole have a small offset, and sometimes the part is literally sliced, like for the layer tangent to the bigger hole (8 mm diameter) or the small hole (3 mm) on the left of the picture where I can see through the part (!)

That part was printed without any support on my CR-X and I noticed that the mirrored part printed in a different position has the same defects on the same layers, so I doubt if can be an issue with the hardware. The slicer is Cura 4.6.1. It takes 6 hours, so I did not watched it and cannot tell if the print is making a pause at some points (I suspected the minimal time for a layer setting for the smallest part, but it is probably not the case for the biggest hole).
Do you know where these weaks could come from?

Here is some additional info to help for the diagnosis:

one proposed explanation is clogging, but i think it is not the case for the following reasons:

I replaced the stock spool holders by ball bearing mounted holders from this design (no issue to print it) and the general setup (after the chassis mod - so is was less rigid to build the part of my question) is now this one, the parts mentioned in my initial post being the ones used to mount the threaded rods so the resistance to extruder steppers is minimal
as told, I printed for the chassis mod 2 x 2 parts from 2 initial designs, and the mirrored part for left/right sides, the defects are quite identical (same Z layer) in each pair of parts, while the mirrored part was turned is a different rotated position around Z axis, but in different layers between each pair (not the same distance from bed). Here is an example of the top mounts for threaded rods (and I remark there is a slice in the middle of a hole, not tangent to it)
I managed to print additional pieces without issue and with satisfactory aspect and no defect at all e.g a improved part for my coffee machine (right of picture) 110 mm diameter / 12.5 mm height

The black parts were printed using basic PLA, 0.15 mm per layer, 190 (or 200 ?) °C for nozzle / 60 °C for bed, 60 mm/s with 8 mm long & 70 mm/s for retraction (and possible Z hop while retracted and during layer change). I am unsure because I did not keep this Cura project but these are my usual settings for now. I have only the machine for a few weeks.
Also: I have checked the belts but they seem neither too loose nor too tighten, while it is difficult to get an accurate idea of the tension. I would rather suspect a Z axis problem (for the slices), but it is driven by dual square threaded rods.

This is typical behavior for low end budget printers, I've seen seen before. Higher end printers generally have a more rigid frame which improves the accuracy of laying down filament. You frequently see this happening where the hotend needs to suddenly change in direction (e.g. the holes), could be high acceleration or jerk settings or just plain high printing speed. For the missing filament, you might be facing clogging or filament that is entangled on the spool. Please add more information on settings and setup of the spool.

@0scar: I don't find it typical. Almost surely there's play in the belts whereby the final position ends up depending on the direction of the move leading up to it. Tightening them should fix it fully.

@0scar: thanks for your attention, I am not sure of what info you want actually so i have edited my question add more context and settings

@R..GitHubSTOPHELPINGICE: the belts seem ok, no too loose, not too tighten but it is difficult to be precise, and to it seems weird that a whole range of layers would have a reproductible offset only on the interval of a hole

You might want to test printing without the heavy spools on top of the frame, that is usually not a good idea (on the other hand you did strengthen/rigidized the frame). Also, 0.15 mm is probably not a native stepper revolution size, try 0.16 or 0.2 mm.

@0scar: I totally agree about the issue of suspended mass, but it is the vendor design. I am planning to build a box around the printer for ABS printing and the spools will be moved to the box frame. Your remark about steppers is interesting. I will try to find steppers and rods accurate specs.


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Material "clumping" when printing
I recently started swapping out my nozzle for different sizes. After a few times using a 0.4 mm, then 0.8 mm, then back to 0.4 mm, I now have this "clumping" going on when printing. The photos are of PLA but this happens with PETG also. Before I started changing nozzles, my prints were perfect.
The blue filament is Overture PLA, printing at 45 mm/s 210 °C (I lowered the temp to 200 °C and it's still happening).

Some things I've noticed (which did not exist when my prints were good):

Melted filament on the rubber piece that covers the underside of the
extruder. Could something be backing up, melting, and then falling in
a clump on top of my print?
The bottom metal piece on the extruder is slightly loose. It's the flat piece attached to the main extruder body with two screws. I don't know what it's called, so I couldn't even search for how to tighten it.

The questions:

Does this "clumping' have an actual name?
What did I potentially do when swapping nozzles that could have caused this (if that's in fact how it started)?
How can I fix it?

Update:
The print stopped and I removed the shroud. My train of thought was spot on as I saw a pool of blue PLA inside the housing and on the nozzle. But I still don't know how this happened.

Looks to me like the bed level is just too high and there's thereby more material extruded than fits in the space.

@R..GitHubSTOPHELPINGICE I added an update, does it concur with your line of thinking or are we now at a different problem?

That means you have at least one other major problem. Probably the nozzle was not properly tightened and material exited at the gap. Having the pressure of the bed being too high would have contributed, but you had a problem either way..

@R..GitHubSTOPHELPINGICE I had assumed nozzles from the same manufacturer were the same height, but I did need to lower the bed. And I tightened the nozzle as much as possible. Problem solved. Thank you

I've adapted these comments into an answer, with some additional content.

From your initial photos, it looks like the bed level was too high, and there was thereby more material extruded than fit in the space. Even with an "identical" nozzle, the distances involved here are on an order of magnitude (less than 0.1 mm) that you're not going to get identical distance to the bed from one nozzle to another.
Further, as you found out following up, not having the nozzle tightened all the way will affect its height, and allow molten material to exit around the gap. It's always a problem not having your nozzle tightened all the way to make a good seal (I actually had nearly the same problem the first time I ever changed a nozzle), but having the bed too close probably made even more material ooze out at the gap due to backpressure.
Hopefully fixing these two things gets you back to printing right. It might be some work to clean out any material left in the hotend, especially if it worked its way around into the threads where the nozzle screws in. Be gentle if you have to clean that out further, since it's easy to strip the threads if you use abrasive tools, and then you'll be looking at replacing the heater block.


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How is a Thermistor supposed to be installed between Heated Bed and the Glass?
opposed to what the title of this question might impose, I'm not new to 3d printing itself and have operated more than one printer for years, however, I feel dumb with installing the Thermistor on this new Heated Bed I got from RepRap.me: Aluminum Heatbed MK3 400x300
The old Mk2b 214x214 Mendel/Prusa heated bed that I have been using for quite a while now has a through-hole in the center, where the thermistor-leads could be fed to from below.
On this new heated bed however, there is a lowering in the very center of the Heated Bed to place the Thermistor in, yet the pads to connect the thermistor leads to right beside it are level with the rest of the Heated bed.
I tried using just a tiny amount of SMD solderpaste and just soldering the thermistor leads as flat as possible to the pads, nevertheless, the glass plate on top is not laying flat and stable on the heated bed with the thermistor installed.
Any suggestions are greatly appreciated on how improve the thermistor-installation onto this heated bed!

Contact the manufacturer and complain, maybe they improve the design or at least refund you.

Try to use a silicone heat conductive pad between heater and glass, where you can make a hole for the sensor. It also helps to improve the contact between aluminium heater and glass, which otherwise may be inhomogeneous (as expected between two quite rigid materials).
They sell them in rolls and you can choose a 1 mm thick one or even 0.5 mm. They are "sticky" but they don't have glue, so you will be able to separate the glass from the pad, even if not so easily as it would be with a clip.

I tried this solution by FarO and can confirm that two 3M 5516-10 thermal pads serve this purpose perfectly. Thanks!


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Over-extrusion on curved surfaces?
I am having issues with my Creality CR-10 S5 running Cura 4.6.1. If I use the Ender-3 G-code, it prints perfect. If I do the exact same print with S5 printer selected, I get garbage prints with lots of burps.

Have you calibrated your E steps?

If both files are printed on the same machine, then incorrect E steps would affect both prints (unless there is M92 call in one of the files, fixing or spoiling the print, e.g. in the start G-code). The one at right looks like it has fuzzy skin enabled. I added an answer with troubleshooting hints, maybe someone can make use of them.

could be diffeerend print speed settings...

Comparing printing results of some G-code with results of samples generated by a slicer with many unknown settings is too superficial. You need to do more insight.
You can learn by comparing G-code files, but I suppose it would not be sufficient to have successful prints. You can also learn from tutorials on how to properly configure slicer. Understanding slicer setting, common printing issues, physics of plascic and printing is very helpful for troubleshooting.
Between files there are number of parameters which could be different, including:

slicer software, its approach (algorithms) and settings - most probably it was Cura in both cases, but many settings could be different - if you have both profiles, then you may comare them setting by setting (thoguh it is not easy in Cura, but see next)
notes in comments (in opening and ending sections of file) - Cura is printing lot of profile settings at the end of the file
G-code initialization commands in opening section of file - *there may be key changes to printer configuration, and also information about following *
temperature settings - you can read it from G-code or from LCD, when print is started
retraction and speed settings - you can read it from E move commands
layer height - you can read it from Z move commands
total use of filament per print - use analyzer, see below
printhead movements (including experimental Fuzzy Skin) - check settings, and use visualisation in Cura just after slicing

Machine profile ("S5 printer selected") in Cura intoduces subset of default settings. In CR-10 S5 profile created by Creality many settings may be very different than in profile for Ender 3. And still author of original G-code file could update many of these settings before slicing.
You can compare two G-code files for the same shape in GCode Analyzer. For easier work you may open two or more analysers in separate browser tabs. There are many useful information calculated from G-code - about Model (like "Total filament used") and and Layer (like "Retract speeds"). Layers may be changed in 2D view with right scroolbar (clik the square scroll indicator and use Up and Down arrows on keyboard).


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Ender 3, unable to level the heating bed
I have an Ender 3 3D printer.
I am having an issue with leveling it, everything I do does not make any change.
The right side of the bed is higher than the left side, that will make me loosening the right side springs completely.
I’ve worked with this printer before and I know it’s should not be like this.

The printer is sitting on a leveled surface.
I have 90° in each of every connection of the stands.
X-Axis is corresponding to the upper stand.
I’ve replaced the regular bed cover for 4 mm ״milky” glass.
I’ve replaced the springs to the stronger ones.
I’ve modify the location of the Z-switch to the lowest corner of the bed.

The frame is prob bent. Can you post a pic of the left and right side bed leveling screws. See this is why I'm an advocate of 3 point leveling (tramming).

Can you add a photo?

Note that a printer itself hasn't to be placed on a leveled table top.

When you do the homing and then do the leveling how much thread you have left that passes the tuning wheel? Verify this on all the four wheels. If you have no thread left then you may consider to lower the Z end-stop.
Check also the Y gantry to see if it is parallel to the base, and make adjustments if needed.


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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

Yes that could be possible, I've seen that before, but that printer used a Fresnel lens that melted sand to glass. But I doubt whether it would be practical. Are you coming from a planet builder perspective?

I was mainly wondering whether oi could be practical to make cheaper printers without an expensive laser

That expensive laser will create a highly concentrated focused bundle of energy (light), it is probably undoable to positioning 5000 mirrors to achieve the same accurate focal point.

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.

authors: حصه القحطاني


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Are there attempts to standardize G-code for FFF/FDM printers?
Rep-Rap project wiki contains information about different G-Code dialects for FFF/FDM 3D printers.
I googled but couldn't find if there were any attempts in DIY community to standardize existing dialects more or less?
For example, M115 command should return meta-information about firmware version and capabilities. But almost each popular firmware doing it in a slightly different way: sometimes they are just using different separators, sometimes constants are structurally different as well.
The result (as I see it) is some standard subset of G-Code commands that can be extended with dialects from different firmware providers. Probably something similar (but better) to what's is SQL world.
Are there any major cons for doing this?

G-Code Is RS-274/NGC
There is no need to attempt to standardize G-Code, the G-code itself already is standardized: it is the NIST RS274/NGC, or often short AIN RS-274 and was not designed for just FDM printers but any moving tool. Power lathes, CNC and laser cutters all can run on RS-274! G0 and G1 always move, G28 is always the homing procedure and so on. To show how the RS-274 standard evolved over time, check out an older variant of the document, the NISTIR 597 Canonical Machining Commands.
Implementation is not standardized!
However, due to the design of a given machine, the exact procedure for these commands has to be different for different designs. For example in a carthesian, prusa style printer Homing is usually moving negatively in X, Y and Z, in that order, one after another. But in a Delta Printer, that would most likely get your printhead to an illegal position: the printhead would first be moved out of the print volume and then never hit any endstop as those are mounted at the top of the printer. Instead, all axis on a delta are moving up simultaneous on homing, stopping each axis as they hit their endstop at the top, then the whole setup moves down to the printbed in unison. On a mill, lathe or router, the G28 operation usually starts by backing the tool away from the work volume, then moving to the 0 and only then moving the tool back into the work area to avoid fixtures.
G & M-command gaps
Another caveat is, that the standardization via the NIST document only encompasses codes G0 to G99 and M0 to M49 - with gaps. Which brings us to the code block M - Miscellaneous. It is not fully defined in the document. FANUC setup uses a few more common M-commands but might contain more. The CNCcookbook has only 16 common M-commands, none of them a reporting one. Autodesk declares even only 11 M-block commands most common: M0 to M9 and M30. Of these the coolant related ones are usually irrelevant for FDM.
M115
M115 and M503 are reporting functions outside of the areas that were pretty much defined by the norming agency and thus have cropped up as development needed them until they formed undefined de-facto industry standards. This means that the standard itself does not contain them, but everybody and bob know that these commands are meant to report firmware and report settings respectively because some popular machines started with it.
These two commands are to inform a programmer what is the brains of the machine and settings, and as such, they are also subject to the style guide of the programming institution - the norm document does not contain a style guide, leaving it free for any implementation to chose style. A working example is Marlin's M115.
However, there are reasons why a programmer might disable M115 but keep M503: Industrial machines, especially such with maintenance contracts, usually don't allow users to access the firmware in some ways to on one hand keep them out from messing with the machine too much and on the other make sure that only a licensed technician can access some reporting functions by using proprietary commands. M503 on the other hand reports on the current status of settings that might be changed by the user or their service technician to account for different print requirements.

Thanks for putting so much effort in your answer. It's really good and I appreciate it. But my point was exactly about some common standards about commands that are not specified by NIST RS274/NGC. The problem, as I see it, is that firmware for hobby/low-end printers are community-driven and everybody is implementing protocol in a bit different way. It's very natural - we had the same in the beginning of WEB era. But my point is if we should bring everybody and initiate discussion about some common protocol and/or format?

The De-Facto standard for G-code is mainly coined by Marlin, which very much works with almost the complete FANUC set (safe for very few afaik) and more commands afaict. If you want to ask someone, you'd have to ask NIST about including 3D printers into the RS274/NGC standard, who then might take what is the de-facto standard.

I can agree with that. Except there Prusa is also very influential on this sector of the market. Rep-Rap wiki page is a great coordination point but it would be nicer to go further. :)

To my knowledge, what we use as G-code is the FANUC base upon which Prusa Research, Ultimaker (via Cura) and the Marlin crews, which are somewhat intermingled, pretty much worked out what they needed more based on that and defined a common set of new commands, but I can not find out what they specifically added.


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Mesh bed levelling does not update any more after MemoryError
I have had issues with printing on my i3 MK3, especially when it came to the first layer. In March 2020, I have installed the Prusa Mesh Leveling plugin for Octoprint. With that plugin and a Nylock nut modification, I was able to reduce the bed variance from 0.6 mm down to 0.014 mm and prints were great. That took about 25 rounds of calibration and I didn't have any issues with the graphics not updating.

Shortly after that, my filament sensor stopped working and I ordered a replacement, which I installed yesterday. But today, my prints are bad again, especially the first layer. So I thought I would simply run through the calibration and mesh bed leveling again.
First, I turned the screws in the wrong direction, so the result became worse and I needed several attempts until the results went into the correct direction. I'm currently at ~1.0 mm bed variance, which is very bad and I need to continue leveling the bed.

Now, the graphics does not update any longer. It always shows the same picture.
I also noticed some different behavior of the mesh bed levelling procedure. Usually, after running the mesh bed levelling, the printer needs some time (~5 secs) before it will react to other commands like a move on the Z axis. I used the following technique to find out when to reload the graphics:

run mesh bed levelling
tell the printer to move up 10 mm on the Z axis
as soon as the print head moves up, it was possible to reload the graphics

Now, the print head moves up immediately after the mesh bed levelling, without the ~5 secs delay and the graphics does not update.
I have already tried:

click the "reload heat map" button
run mesh bed leveling again
restarting Octoprint
resetting the printer using the X button
looking for disk space via SSH

.
pi@octopi:~ $ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       7.3G  1.9G  5.1G  27% /
devtmpfs        182M     0  182M   0% /dev
tmpfs           186M     0  186M   0% /dev/shm
tmpfs           186M  2.7M  183M   2% /run
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           186M     0  186M   0% /sys/fs/cgroup
/dev/mmcblk0p1   42M   21M   21M  51% /boot
tmpfs            38M     0   38M   0% /run/user/1000

In the log file (octoprint.log) with output level set to DEBUG, I could see an entry:
2020-06-06 12:19:52,261 - octoprint.plugins.PrusaMeshMap - INFO - Generating heatmap
2020-06-06 12:19:52,288 - py.warnings - WARNING -
    /home/pi/oprint/local/lib/python2.7/site-packages/matplotlib/pyplot.py:522:
    RuntimeWarning: More than 20 figures have been opened.
    Figures created through the pyplot interface (`matplotlib.pyplot.figure`) are
    retained until explicitly closed and may consume too much memory.
    (To control this warning, see the rcParam `figure.max_open_warning`).
    max_open_warning, RuntimeWarning)

As you can see, this was at 12:19. The last graphics I saw is from 12:37.
The logs also contain a message on 12:40:
2020-06-06 12:40:39,262 - octoprint.util.comm - ERROR - Error while processing hook PrusaMeshMap:
Traceback (most recent call last):

  File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 2849, in _readline
    ret = hook(self, ret)
  File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint_PrusaMeshMap/__init__.py", line 90, in mesh_level_check
    self.mesh_level_generate()
  File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint_PrusaMeshMap/__init__.py", line 236, in mesh_level_generate
    fig.savefig(self.get_asset_folder() + '/img/heatmap.png', bbox_inches="tight")
[...]
  File "/home/pi/oprint/local/lib/python2.7/site-packages/matplotlib/image.py", line 512, in _make_image
    output = self.to_rgba(output, bytes=True, norm=False)
  File "/home/pi/oprint/local/lib/python2.7/site-packages/matplotlib/cm.py", line 259, in to_rgba
    xx = (xx * 255).astype(np.uint8)
MemoryError

On 12:46 I rebooted the system
2020-06-06 12:46:08,761 - octoprint.server.api.system - INFO - Performing command for core:reboot: sudo shutdown -r now

but of course that graphics is still missing and the last available graphics is the one from 12:37. So, after the reboot one needs to run the mesh bed leveling again.
Still, no luck...
OctoPrint version is 1.4.0, OctoPi version 0.15.0PE, Prusameshmap Plugin: 0.3.0. As far as I can tell, that's the latest version available.
What can I do to make mesh bed leveling work again?

Is this still a problem? I suspect this is a bug in the plugin. Note this bug report, this is probably the same issue, but it has been closed!

@0scar: it has been closed, but there's no code fix associated with it.

I have formatted the SD card and installed Octoprint from scratch. That's nasty, because I lost all the models I uploaded.
It seems to be a bug in __init__.py of OctoPrint-PrusaMeshMap (archived Github repository).
That code saves the heatmap in this line:
fig.savefig(self.get_asset_folder() + '/img/heatmap.png', bbox_inches="tight")

It uses Pyplot
import matplotlib.pyplot as plt

and thus the code should probably use (untested!)
plt.close(fig)
del fig

to free the resources.
Unfortunately it's not possible to file this as an issue because the Github repository is in archived mode and thus readonly.

You have found a bug in the OctoPrint plugin. As you noticed, not more than 20 graphs can be created/open at a time. This implies that the developer has not implemented pyplot correctly, this is a common mistake that I have ran into myself once or twice. You should notify the developer.
The problem is that the old graph is not destroyed or not properly updated (I think it is intended to update the graph). The code passes the create plot multiple times and after 20 graphs it will drop the error message.
If you reset the Pi or reload the Octoprint server you are probably good to go for another 20 graphs.


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Enclosed volumes with stereolithography 3D printers
I have no prior experience with stereolithography 3D printers.
For a research application I am considering the SLA approach but I have a more basic question.
I would like to use SLA in order to print porous structures from ice cores. Using X ray tomography I have raw data of very high resolution 3D images of the cores. The idea is to use this information in order to print representations of these cores to perform a diffusion study.
Some of these cores come from depths below 50 m thus the snow has compacted in such way that volumes of air are occluded.
My question is if it is possible for SLA printers to print in such enclosed volumes. Imagine for example a solid cube with a gas bubble in the middle. Is that possible for an SLA printer and if yes will the bubble contain air or the liquid resin of the printer?

I like your question.  I don't have an SLA printer.  It is somewhat unnatural to have enclosed volumes in an SLA printer.  It could be either filled with uncured resin, or, if the size of the opening, the viscosity of the resin, and the draining time per layer are right, perhaps partially filled with air.  "Partially" because uncured resin will stick to the inside.  It might be later cured in the UV soak process, but I think you lose control of the geometry.

@cmm here is a video of a scan, where you see white think void, black is filled solid material (in the real case ice and in the #D printer case plastic)
https://youtu.be/oTDOVxpl6PU

VERY related: Why is cupping bad in SLA prints?

@Dr.MantisTobbogan - Finally, I posted a meta post on some editing guidelines.

yes..but.. practically you'll want to add a pair of vent holes to let the fluid escape (one for air one for fluid) you can have a large void in the print, but you'll need some post-processing to deal with it. You'll first have to drain the bubble, then clean it, then fill it with the gas you want, then seal it. I can't think of a simpler way, but there might be?

The bubble will contain air, but this will vary by printer. Most resin printers lift the printed part out of the bath slightly after each layer. Some printers, however, don't lift the piece completely out of the bath. This will cause the resin to become entrapped. Once those entrapped pockets of resin are exposed to light, they will also undergo photopolymerization. It may be possible however to program those printers to lift the part completely out of the resin for each layer.

actually, due to how easy it is and speeding up the print, these days most don't lift it out of the resin vat but just raise it enough to separate it from the build surface. However, it's just a modification of the g-code increasing the raise it over that threshold... or the firmware.

Some (all?) slicers allow you to control the lift distance. If you put a lift that's higher than your vat depth, you'll get the part out of the resin bath completely every time, at the expense of a huge increase in print times.


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How to solve ABS deformation at the bottom?
I am printing small mechanical pieces in ABS:

100 ºC bed temperature
70 ºC Room temperature
250 ºC nozzle temperature
0.4 mm nozzle, at 0.15 mm per layer.
100.8 % scale to compensate ABS dimensional innacuracy.

The first layer is printed correctly, but later, corners warp and first 10 mm get deformed (See images).

How do I solve this? Unfortunately, I cannot increase room temperature over 70 ºC
Here is a picture while printing, we can see that the edges get warped even far over the first layer. (Sorry, the picture quality is not so good):

Are you using anything to aid bed adhesion?

No, because the piece seems to stick enough (at least first layers). I will try with some acetone/abs mixture

A warmer room and enclosing the printer can help, too.

Warmer room than 70 ºC? Supposing that electronic inside could manage it, which temperature do you suggest?

My ABS printing experience is limited and from a long time ago, but, the up-curling of overhangs is also common for e.g. PETG, it is a part fan cooling problem. What part cooling settings do you use, none, partly or full?

For this print, I set the part-fan to 0 % (trying to increase cool-down time) . Should it be 100 %? 50 %?

I thought so you weren't using cooling, you should, but not 100 %. You could also look into minimal layer time.

Great report on your several tries, good to see you varied a lot of options. Note that I have learned that because of the heated chamber, you might need more cooling a single fan can provide! Maybe the whole part should be an answer on itself, I'll vote for it, this shows some thorough variation of print parameters and draws conclusions from the research. Please consider moving this to an answer!

Hi, I agree with @0scar, I think your last edit detailing the 5th and successful attempt should be posted as an answer. :-)

The up-curling of overhangs is frequently seen when printing PLA or PETG when the just deposited layer hasn't been cooled enough. The residual heat will allow the curling as the plastic has not been fully set (above the so called glass temperature) because of insufficient part cooling.
Knowing that ABS doesn't need much cooling (to improve the inter-layer bonding), you most probably will not require full power of the fan (depending on the cooling power of the fan). You do need a little cooling though, but not for the first (few) layer(s), so keep the fan off at the first layer. Be sure it is up to speed at the layer you require the cooling as the first few percentage of the fan is generally not enough to rotate the fan. E.g. my fans start spinning at about 20-25 %.

Results of the suggestions in comments and answers
Following are the results, coming from the great answers received on this page. I post them here in case it can helps further readers in achieving good results.

Note: when two numbers are indicated, the first is for the first layer, and the second for the rest of the piece. (e.g. 250 ºC / 230 ºC)

If you want to see the result, go now directly to the bottom of the answer :-)

Note2: Pictures are taken from the worse side. In some cases, other sides are much better.

First try:

Nozzle temperature: 250 ºC / 240 ºC
Platform temperature: 100 ºC
Chamber temperature: 70 ºC
Speed: 60 mm/s
Fan: 0% / 50%

Second try:

Nozzle temperature: 250 ºC / 240 ºC
Platform temperature: 100 ºC
Chamber temperature: 70 ºC
Speed: 20s / layer
Fan: 0% / 50%

Third try:

Nozzle temperature: 250 ºC / 240 ºC
Platform temperature: 100 ºC
Chamber temperature: 70 ºC
Speed: 20s / layer
Fan: 0% / 100%
95% flow

Forth try:

Nozzle temperature: 245 ºC / 230 ºC
Platform temperature: 100 ºC
Chamber temperature: 50 ºC
Speed: 20s / layer
Fan: 0% / 100%
95% flow

Fifth try (succeed):

Nozzle temperature: 245 ºC / 225 ºC
Platform temperature: 100 ºC
Chamber temperature: 40 ºC
Speed: 20s / layer
Fan: 0% / 200% (I added an additional fan)
95% flow

My current settings: (in case it helps)
At the end, I opted for the following setup, which seems to adapt better to all kind of shapes:

Nozzle temperature: 250 ºC / 250 ºC (slighty higher temperature help adhesion between layers and give better piece resistance)
Platform temperature: 100 ºC / 80 ºC (80 ºC I had some piece deformation over 85 ºC, especially big pieces)
Chamber temperature: 50 ºC
Speed: 40 mm/s, or even 30 mm/s (Help adhesion and good precision)
Fan: 0% / 200% (I added an additional fan, helps avoid deformation in corners, as described in the question)
Scale the piece 100.5% (ABS shrink)
Minimum layer time: 20s (For small pieces, this allows each layer to cool enough)
Build Plate Adhesion: Brim
100% flow

Conclusions:

The solution is to cool each layer as much as possible and as soon as possible, BUT avoiding warping.

Use a very strong adhesion to avoid the warping, allowing a better cooling of each layer. In my case I started to use a cheap and strong hairspray (which works surprisingly well).

Using chamber temperature over 50 ºC make it more difficult to cool each layer quickly, thus, it is not recommended.

Using ventilation is a must.

Different configuration for first layer and consecutive layers helps.

Is the fan speed based on layer time? what are the settings? 0%/200% is unclear

0% is for the first layer, and 200% (full speed of both fan) for the 2nd and further layers.

We usually stick the masking tape on the printer's bottom plate, so that the model is formed on the side of the masking tape which without glue, which looks good.
When there is no masking tape, we sometimes manually adjust the height of the bottom plate to make the nozzle appress to the bottom plate when printing the first layer. At this time, the melted material can hardly flow out. The strong pressure will adhere the material tightly to the bottom plate, which can effectively solve this problem. However, this may damage the extruder motor.


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

For your application, you should 3d print a positive model, then make a silicone mould negative of that model. Then use the silicone mould to make the final chocolate. Clean the silicone thoroughly before initial use. Fill gaps in the 3d printed model with a light epoxy resin. Use mould release and ensure you wash and sterilize that silicon mould before using it with chocolate.
An actual chocolate printer is not easy to come by, as a normal 3d printer converted to use chocolate is not able to be sterilized for food use.
The video in the link illustrates one person's attempt at this process.

That video was spectacular.

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

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

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

I prefer ... process speed

Printing is unlikely to win that battle. You might print a plastic mold once you can use for casts, but if you do make sure you use a liner of some kind. 3d-printed plastics are not considered food-safe.

I got idea to make the bust from plastic and use it for making the mold from some food-safe silicon.

That could work very well.

Direct printing of chocolate is tedious because if it doesn't solidify very quickly (like, print in a chilled environment) you wind up printing a chocolate puddle. I've done it.

authors: أريان ديلا كروز


text:
Converting / measuring bottle threads for creating an adapter to it
I'm trying to model the threads of a "Poland Spring" 500 ml bottle so I can 3D print an adapter for it. But I can't find information about it. I emailed them but they said they didn't have the information.
How can I find this information out?
The bottle seems to use non standard threads. It uses 3 threads 120 degrees apart that does not go all the way around.   Any information on how to get this information?

You can use a program known as OpenSCAD with the threads library to assist your objective.
The important aspects of a thread are the major diameter (outside diameter at the thread surface), the length of the bolt/nut and for your project, the start count. The noted library has a parameter called n-starts, which covers your triple start requirement.
It may require some trial and error processing, but you have a good foundation with OpenSCAD library.
Even if the bottle is manufactured with Imperial reference (unlikely), you'd probably have an easier time with metric threads. I just checked a Dasani water bottle, which measured at 27.27 mm major diameter, 10 mm length, thread pitch 2 mm. The thread pitch in metric is the distance between peaks (or valleys) from one to the next. This particular bottle has an interrupted thread, but that should not be a factor for creating an adapter.
This Dasani bottle does not have a multi-start thread. It's not a complete thread, but it is single start. Considering that a water bottle top has minimal length, you may also have an interrupted rather than a multi-start thread.
The code for the measured thread in OpenSCAD is relatively simple.

use <threads.scad>;
thread_dia = 27.27;
thread_pitch = 2;
thread_length = 10;
metric_thread(thread_dia, thread_pitch, thread_length, n_starts = 3);

The above code would generate a 3-start thread in the form of a bolt. Using a difference() code would provide for the inverse required for your proposed adapter.

top image is single start, bottom is triple start.
Top view comparison:

It's really unlikely that a bottle is using nonstandard threads; the engineering and tooling cost for doing so would not make sense. Most plastic drink bottles use PCO 1881 or PCO 1810 threads. If not, it should be one of a number of other less widely used standards.
The industry term for drink bottle thread is "neck finish". Searching on that, or on one of the standard names like PCO 1881, will find you a lot of information. You can then try to find a match for your threads. Note that the breaks 120 degrees apart do not affect the thread design, and may or may not be part of the neck finish standard, so you can ignore them.
There are existing OpenSCAD libraries for some of these, including

threadlib
IoP-satellite

And some related articles on Hackaday about their development and use:

Learn The Secrets Of Matching Bottle Cap Threads To One Another
Generating Nice Threads in OpenSCAD


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Is there a more efficient methods of removing support in a model?
Is there a way of reducing the amount and strength of Model support when slicing in Cura?
Cleaning a model with large amounts of support can consume large amounts of time.

There's a lot that can be done to improve the removability of supports, and much of this is not widely known/published.
One big wrong default in Cura that contributes to problems with support is Limit Support Retractions, which defaults to on. This causes heavy stringing between components of the support structure that should be separate, and poor layer adhesion between layers of the support and between layers of whatever is printed right after the support (!!), making support more brittle and difficult to remove in clean chunks. This setting should be turned off.
I find Enable Support Brim is also useful. Its nominal purpose is to make supports adhere to the bed better, but it also gives them more of a solid bottom so that the structure is rigid and admits snapping off as a chunk.
A nonzero Support Wall Line Count (it's zero by default for zigzag and most support patterns, but one by default for support tree and others) can make chunks of support easier to remove by making them more rigid.
Connect Support Lines (also called zig_zaggify_infill) helps with rigidity too, and with reducing time wasted on retractions once you turn off Limit Support Retractions.
Aside from these less-well-known tunables, the obvious ones are Support Z Distance and Support X/Y Distance, especially Z. You can increase this slightly from the default to make supports easier to remove, but it will hurt the quality of the surface just above the support (making it less flat, more stringy like a bridge). And the biggest one of all is Support Angle. Generally increase it as high as you can go, after doing some test prints to determine the maximum overhang angle you can print without support. This will save material and make it easier to remove what supports remain.
Finally, aside from support options, you want to make sure you don't have underlying print problems causing oozing, bulging, or other dimensional-accuracy/extrusion-accuracy issues. This is because any material that is printed or expands into the wrong place will, if it's adjacent to support material, bond to the support material and make it hard to remove.

I am getting heavy stringing so I will look into your comments. Thank you

You could reduce the Support Density:

A higher value results in better overhangs, but the supports are harder to remove.

Furthermore read this answer on question: "Difficult to remove support material".


text:
Is there such thing as a sealed dual extruder hot end?
Does anyone know of a hot end that is sealed? What I meaning is that the hot end has a rubber seal where the filament enters to keep the top airtight (in order to eliminate oozing).
I am looking to build a dual extruder printer but, I do not want any oozing from the hot end which is not in use. I could build a system to retract and 'close' the nozzle but it would be much more elegant if it would work to just seal the top of the hot end. Thus achieving the same effect as when you pull up water with a straw by covering the top with your finger.

In a true dual-extruder / dual hot-end printer, having a seal isn't necessary.
On my dual-extruder printer, the non-active extruder does an aggressive retraction and then drops the hot-end temp down to a stand by temperature which is lower than the melting point of the filament.  Because it had an aggressive retraction ... and it's cooling ... the filament doesn't seem to ever make it out before it has cooled to the point where the filament drops below the melting point.  While there is no 'seal' ... it doesn't ooze.
The slicer software (I use Cura) estimates the time remaining before the extruder needs to become active and will start to pre-heat the hot-end so that there wont be much (if any) delay.  Once the extruder becomes active, it will re-prime and will usually move to a prime tower to get the filament flowing again ... while the other nozzle (the one that just became inactive) does a retraction and starts cooling down.
With this technique of retracting and lowering the inactive hot-end to a standby temperature, I have never personally experienced an issue with oozing.

Is there any noticeable increase in print time using this method? :)

Cura seems to estimate the amount of time needed to raise the hot-end back to print temp.  While one toolhead is printing, it seems to work out how far in advance it should start heating the next toolhead -- which (amazingly enough) always seems to reach printing temp just as the active toolhead finishes.  I never really experience a delay (except for extruding a little into the prime tower to get the filament flowing nicely again.)

I should add ... only one of my printers is a dual-extruder.  So I don't know if I'm just lucky ... and/or if others do experience delays with their printers.

It doesn't work that way, or perhaps in some sense it already does.
The "straw effect" you're describing depends on the water not being under any pressure that exceeds the outside atmosphereic pressure. If you squeeze the straw or otherwise apply pressure, it will immediately spill out.
If you're printing at more than a ridiculously slow print speed (slow enough that it would fail for other reasons, like the nozzle melting the already-printed part just by proximity to it), the filament is under very high pressure from the extruder gear. The primary function of retraction is not to move the filament back out of the nozzle orifice, but simply to relieve that pressure. (A little bit more is needed to prevent oozing, however.) When retraction happens, it's exactly like the "straw effect" you're describing. The material pulled back out of the hotend into the heatbreak hardens enough that it makes a nearly air-tight seal, preventing the molten material below from flowing out of the nozzle due to gravity.
If your hotend does not have design problems and if you're using retraction correctly (that means using it everywhere that you're making a move that's not an extrusion one, not skipping it with "Limit Support Retractions" or "Combing"), you should not see oozing, ever. The system already works the way you want it to. But you can't magically get rid of the need for retraction. It's part of how the system you want works.

Assuming there is no humidity in the filament which expands with heat and keeps pushing the filament out (typical with humid nylon and PETG).

This appears only to be valid for single nozzle extruders, since the inactive nozzle will be ”printing at insanelt slow speeds” when it’s not in use.

@BeaconofWierd: that part of the answer is just explaining why retraction is needed. You're talking about what's a travel move for the inactive nozzle, and as long as it's made retracted everything should apply. The duration of travel for the inactive extruder is so long that you might get some oozing due to imperfection of the system/model but that's independent of the part of the answer you seem to be objecting to.

@R..GitHubSTOPHELPINGICE I'm not saying it's a bad answer, but from what I've read oozing is an issue with dual extruders for the inactive nozzle and that retraction only temporarily fixes oozing, which is enough for single nozzles. But as you said, there's pretty much a seal already in the hotend itself after the retraction, so adding another seal probably won't do much.

@BeaconofWierd: Indeed. I suspect the problem is that you don't have the surface tension effects you would with water, so the molten plastic eventually runs down. Not a lack of seal. The only real solution I can see, if the "travel time" for the idle nozzle is long enough that this starts happening, is actively cooling it below the temperature that the material can flow.

@R..GitHubSTOPHELPINGICE Actively cooling the nozzle would probably work, though it can take time and require rather expensive hardware. I guess I would have to investigate further into why oozing happens in an inactive nozzle, the surface tension of PLA around 200 degrees is only about half that of water, so my initial guess is that there's something else going on here. It might simply be that the filament doesn't have a perfect seal and that air is slowly leaking in to equalize the pressure over time. I guess simulating it would give some answers. Fluid Mechanics, we meet again!

I can't actually get my nozzle to steal against the aluminium heat block. No matter how tight I turn it air always leaks through, would you mind testing this too? Maybe I just have cheap, poorly made nozzles, but if that's normally the case it could explain why retraction only prevents oozing temporarily.

@BeaconofWierd: How do you measure that it's not sealing? Does your setup have PTFE all the way through to butt against the nozzle, or is it "all metal" in the hotend with PTFE (if any) ending in the coldend/heatbreak? A diagram might help understand what you're saying

@R..GitHubSTOPHELPINGICE I have a PTFE tube all the way down to the nozzle. My "highly scientific" method of measuring the seal was just to suck and blow into the tube and directly into the heat block with only the nozzle attached. There were clear leaks both times.

Let us continue this discussion in chat.


text:
3DTouch activating but responding too late
I installed a knockoff BLTouch called the 3DTouch on my Sidewinder X1. The sensor triggers correctly, however, the printer responds to the signal way too late.
For example, I was testing it and decided to trigger it with my finger to see if it was responding at all. After the trigger the printer continued downwards for another 3-4 inches, this would put the head below the bed if I let the bed trigger it. The printer just seems to get the message way too late.
Has anyone encountered an issue like this before, part of me thinks it's a calibration issue but honestly it is so far off that I am not sure.
I think it is firmware but I followed this tutorial, Touch Mi vs BLtouch on the Artillery3D X1 + MKS TFT babystepping, specifically for the sidewinder X1 to a T so I don't know what I am missing.

The head is stopping once triggered, it's just stopping too late. If I trigger it while it is up high when it goes down a couple of inches and then starts the rest of the self-level procedure.

This sounds like the firmware isn't correctly configured, have you double checked your changes? Do note that the quality of the kick-off sensors isn't that good, I've had multiple fail, the original works fine. The retraction of the pin does not necessarily imply that the signal arrives correctly to the printer controller board.

I think it is firmware as well but I followed this tutorial specifically for the sidewinder X1 to a T so i don't know what i am missing.
https://www.youtube.com/watch?v=V3zEJGOcz7s
The head is stopping once triggered, its just stopping too late. If I trigger it while it is up high when it goes down a couple of inches and then starts the rest of the self-level procedure.

If the pin retracts, that means that the sensor itself is working fine (unless a huge firmware bug is present, which is unlikely) and detected the touch. I would recheck the firmware configuration.


text:
Resume print but no extrusion
Had a print stop about 20 % through and read through some old questions (3+ years) so I'm posting again.  Apologies if it's in here some where...
Found the layer to restart, deleted everything from layer 0 to layer 77 (in my case)
The set the E value to the value in layer 76, but still no extrusion.  Using Ultimaker Cura.  I can dump this but really want to know for future issues with larger prints...
EDITED AFTER ANOTHER ATTEMPT:  (Same effect)
Sorry, I'm at a loss
also made change to G92 code subtracting 5
Here is the start sequence:
;FLAVOR:Marlin
;TIME:41644
;Filament used: 21.0489m
;Layer height: 0.2
;MINX:29.678
;MINY:92.227
;MINZ:0.2
;MAXX:198.806
;MAXY:194.503
;MAXZ:65.6
;Generated with Cura_SteamEngine 4.6.1
M140 S50
M105
M190 S50
M104 S200
M105
M109 S200
M82 ;absolute extrusion mode
; Ender 3 Custom Start G-code
G92 E0 ; Reset Extruder
G28 ; Home all axes
G1 Z2.0 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 Z2.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
G1 X5 Y20 Z0.3 F5000.0 ; Move over to prevent blob squish
G92 E0
G92 E0
G1 F2700 E-5
;LAYER_COUNT:328
G0 Z15.6

G92 E1744.14148
;was G92E1749.14148

;TIME_ELAPSED:19808.769206
;LAYER:77
;TYPE:SUPPORT
G1 F2700 E1754.14148
G1 F1500 X73.481 Y110.942 E1754.14217
G1 X74.078 Y110.968 E1754.16204
G1 X74.527 Y110.792 E1754.17808
G1 X75.311 Y110.007 E1754.21498

You asked it to extrude 1.7 m of filament.

What is the purpose of those 19 non-printing moves?

Not sure Davo, I just cut out the layer detail, I can delete that also if it doesn't do anything

The line you added:

G1 E1749.14148

asks the printer to extrude 1.7 meters of filament. The firmware likely has a feature to ignore such excessive requests as bogus. Then, subsequent extrusion amounts are also huge (1.7m+) relative  to the current extruder position (0) and also get ignored. What you meant to do was:

G92 E1749.14148

which means "set the logical extruder position for its current physical position to 1749.14148 mm" so that subsequent extruder positioning commands are interpreted relative to that initial position.

added and edited op, same result though, unfortunately.  gears still not turning (checked just in case I had a clog)

I just noticed the E-5 retraction just before the start - if not reversed, is going to prevent any extrusion from happening for a while. Could that be all that's happening? I would set the logical position to 5 less (1744) so that the first extrusion move also undoes the retraction.

so change G92 E1749.14148 to G92 E1744.14148?  Or could I just delete the E-5 line?

If you delete the E-5 you should expect to see oozing all the way from the end of the prime line to the place where printing resumes. That's why I'd prefer doing it the way I suggested.

OK I'm sorry I know this is something I'm doing wrong.  changed the line and updated the op to current config and still no love.

Do you see the extruder trying to turn at all? Is the hotend at 200°C?

200 degrees yes, extruder does not move at all, I can push manually through and filament passes like I'd expect, though.

he's operationg under M82 ;absolute extrusion mode, and sets the extruder to position 17-meters-something G92 E1744.14148, so subsequent extrusions should be higher than that.

@Trish: See edit history.


text:
Sending a 3D model from Fusion 360 to Ultimaker Cura for printing fails
How do I 3D print to Ultimaker Cura from Fusion 360?
(from: File > 3D Print)
I added Cura to the 3D print list, but whenever I click OK, the application does not open.

Works just fine for SuperSlicer / PrusaSlicer. Fusion 360 simply creates an .stl and opens your specified slicer with it - similar to dragging the file over a link to the application.
Must be a Cura problem.

If you use the "Custom" option, you can set that to Cura.exe from the correct directory and use that.


text:
Is nozzle no longer heating up correctly related to hotend insulation being pulled off?
The insulation of the heater block got pulled off...
I was trying to print ABS on my TEVO Tornado, overnight. But I not-so-smartly left the window open overnight, thinking it was alright (as to remove the fumes) but then it warped so much that it pulled off the insulation of the hotend.
It is no longer heating up to over 200 degrees Celcius. It starts showing a message saying PRINTER HALTED: PLEASE RESET Should I just re-insulate it? if I should, what do I use for insulation?

Yes I had this same problem myself.
You will need to re-insulate it using a silicone block and next time don't leave the window open while printing. Just keep the fan or AC on to circulate the air.

the printer halted error could be caused by thermal runaway

And it would be a good idea to do the PID tuning for the hotend after changing the insulation.


text:
Additional mods for printing metal filled filament with Ender 3 V2?
I am thinking about getting into the 3D printing craze and currently looking at purchasing a Creality Ender 3 V2 as an entry-level unit. I would like to print using the normal PLA, PETG, ABS, etc. but I'm also thinking of metal-infused PLA or similar for printing jewelry. The suggested modification that I have found in researching is the Micro Swiss All Metal Hotend in order to reach the higher temps for printing metals.
Am I correct with this additional mod? Are there other Hotends that would better? Any additional mods for working with metals?

What do you mean by "metals"? You can get PLA infused with metal particles that looks vaguely metallic, and shouldn't need any special equipment for it, but you cannot print actual metal with a normal FDM printer. Real metal printers need high power lasers to melt metal powder and cost tens of thousands of dollars.

Yes, I was looking at using infused PLA. I will edit to clarify.

There is a lot of misinformation in the 3D printing world about "all-metal hotends" being an upgrade. Some of them, especially clones, are not even all-metal but just poor lookalikes that create all sorts of problems. But even if you get a real one, it's a trade-off, not an upgrade. It lets you print materials that need a hotend temperature over 250 °C (over which the PTFE liner will begin to degrade and possibly release small amounts of harmful gasses) up to the temperature your heating element can achieve, at the cost of losing the extremely-low-friction PTFE pathway all the way to the nozzle, which aids with smooth extrusion and retraction and avoids jams. Depending on your particular all-metal hotend, it may be harder to get retraction working correctly than with a normal PTFE-lined one. Some users report very good results, others lots of problems.
There are very few materials that need temperatures over 250 °C to print that don't also need a much more expensive machine (or at least a heavily-modified one) for other reasons, such as requirement of a high-temperature enclosure. The main materials that can be printed on an Ender 3 with an all-metal hotend but not the standard PTFE-lined hotend are polycarbonate (needing 255-300 °C) and some forms of nylon (which may need up to 250-270 °C). All the other non-exotic materials, including PLA, ABS, PETG, and TPU, and even some exotic ones like POM (aka delrin or acetal) and many nylons, can be printed just fine with a stock Ender 3 (possibly with a minimal enclosure built around it).
In particular, for the purpose you want - printing metal-infused PLA - there is no point whatsoever in an all-metal hotend. Metal-infused PLA is printed within the temperature range of PLA, which is typically 230 °C at the absolute highest (and preferably much lower) and the printer you're looking at should print it just fine out-of-the-box (or rather, once you assemble it).
If you're concerned about abrasive wear from the filament, this affects the nozzle not the hotend. Technically the nozzle is "part of" the hotend assembly, but it's easily removable and generally considered a consumable item that you replace periodically. You can get hardened steel nozzles and all sorts of other exotic replacements designed not to wear out from abrasive materials, but the standard brass has the best thermal (heat conduction) properties and is so cheap you're generally better off sticking with it and buying a pack of 20 or so to have on hand when they eventually need replacement. In any case, there's no need to replace the hotend with an all-metal one to deal with nozzle wear; you can get either type of replacement to fit the original one.

Within that misinformation you speak of, is it true that metal-infused filament will ruin/damage the print nozzle quicker than regular filament?

Yes, metal-filled or even wood PLA will damage your nozzle. As long as you don't plan to print higher-temp materials (Nylon, Polycarbonate), a hardened nozzle will be sufficient without the potential drawbacks of an all-metal hotend.
https://www.youtube.com/watch?v=uvlMeTnjriQ

@agarza: No, the misinformation I speak of is the claim that all-metal hotend is "an upgrade" and something you're "supposed to do" to improve your printer rather than something you do only because of a very specific need. It's not misinformation that certain filaments will damage the nozzle quickly, but that's completely unrelated to your question about an all-metal hotend. If you're using abrasive filaments you either replace your brass nozzles frequently (they're dirt cheap so this is no problem) or buy a steel nozzle. (Steel is also a trade-off since brass has better thermal properties.)

To clarify since I realized it may not be obvious: the nozzle is a replaceable part of the hotend, generally considered a consumable. You can get all sorts of different sizes and materials of nozzles for the original hotend that comes with your printer.

So it's better to use a normal, PTFE lined hot-end for materials like PLA where an all-metal could be helpful for ABS? If that's so, I can imagine switching hot-ends whenever switching filament.

You do not need to change your hotend for ABS either. Or for PETG, or for TPU, or even POM (delrin) or many nylons. Of things printable without an extreme machine, pretty much only PC (polycarbonate, 255-300) and some high-temp nylons (250-270) need an all-metal hotend.

@R..GitHubSTOPHELPINGICE Thank you for the insight. It will definitely help in reducing certain costs.


text:
Three RAMPS boards wasted by plugging in a heated bed
I have a DIY 3D printer. Everything works fine except the heated bed. When I plug my heated bed to the D8 terminal smoke comes out.
This is my third RAMPS board that I have had this problem with. After it burns the RAMPS still works but the heated bed doesn't stop to heat. I am using a 12 V 30 A power supply.
Is it something about my power supply?

We will need some more details on the heated bed you're using and how it is connected. The RAMPS can only handle around 11A for the heated bed. Maybe your bed draws more than that?

It's probably not the power supply.
Please measure the resistance between the two wires which lead to your heated bed - perhaps there's a short which causes an excessive current draw.
It's also usually recommended to use an external MOSFET for the bed - which is easier and cheaper to replace than the entire RAMPS in case it fails.

my bed is 1-1,2 Ohm. Its drawin too much current for ramps. I will use externel Mosfet. Can the externel Mosfet stands my power supply?  Its 30A

It could be a couple of issues:

the heated bed tries to use more power than the ramps board is capable of because the traces on the board aren't big enough to get rid of the heat.

the thermistor is broken / not properly connected or configured, and it keeps on heating the bed forever.

a short somewhere in the wiring.

My advice:
Check the wiring. If there is no short, check your thermistor. Is it reporting the right temperature? If it reports the right temperature, try using a external mosfet module for the heated bed. These are fairly cheap, and easy to connect.


text:
"print" menu not loading on Monoprice MP Select Mini V2
I have an MP Select Mini V2 and when I turn on the printer and select the "print" menu it hangs while saying "please wait" instead of listing the .gcode files stored on the SD card.
I have been using that printer with that SD card for hundreds of prints without error. It started when I took it out and added a new .gcode file (sliced in Cura with the same settings as I always use) and placed it back into the printer to print it. When I connect the SD card into my computer (Windows 10) everything seems normal with the card.
What could be causing this issue?

Please remove this file and see if standard behavior resumes. It's possible that the file name is too long, or has a special character.

Too many files on SD card
I removed some files and now it works, it seems like the menu would not load if the SD card contained more files than the printer could display on the print menu (they didn't take up a lot of space in memory, though).


text:
LCD/DLP resin curing system
I'm trying to develop a device to burn a glass slide surface with a special pattern of UV light (between 300 nm and 360 nm) in a 5 cm square surface.
I've read several threads asking questions about LCD printers and their way of functioning but I am not entirely sure how they work. So far I have found two methods that explain LCD printers:

The LCD screen emits light in UV spectrum that causes the resin to cure. I don't believe there are any LCD screens that can emit at 360 nm.

Initially there's a UV light bulb 'behind' the LCD screen which is translucent when off. The pattern is drawn in the LCD screen interfering with UV light's path drawing the image in the plate.

If option two is the right one, do you know any devices (uv light and lcd screen) to develop what I want within the 360 nm wavelength?
Alternatively, can a DLP projector to emit UV light (by adding a UV light bulb)? Would it still need to be cured?

LCDs can't emit light full stop. There is always a light source behind the LCD which is blocked by the LCD.

It's almost always what you call system 2:
The LCD screen is acting as a "mask" for the UV backlight, which is a strong bulb under it. This also is the reason that the screen degrades over time and that the machines need replacement bulbs: the heat from the UV source burns out the screen and itself over time. Both parts are consumable, just like the screen.
You could technically swap out the light source for any one that fits the machine. However, a 360 nm light source won't help you for printing resins at all: most resins you can buy cure between 395 and 410 nm.
Yes, even by curing with an UV light source, you need to post-cure the print. The reason for that is to get rid of any uncured, not washed away resin that still sticks to the surface and that a 3D print right of the platform actually isn't cured fully - especially the inter-layer-bonds are not formed fully and curing in the lightbox increases the stability to the print a lot.

This would imply a transparent LCD screen then... I'm trying to find one (or an OLED one) that I could use for my project but without luck.

@Shupper you need to take apart a full LCD screen and remove the backlight.


text:
How do I remove a stuck resin print
I have stuck resin print that won't detach from the bed of my Creality LD-002R LCD Printer. I guess I could break the print off piece by piece, but it won't budge with pressure, pulling with all my strength, or even hitting it pretty hard.

Being wary of getting any resin anywhere you don't want it, can you put the bed+print in a fridge for an hour or so?

Very carefully :D

The freezer did it, but the thermal shock broke the print (and I still needed a spatula!). Perhaps the fridge is indeed the way to go... trying that with the second round.

Nomenclature ERror: it's an LCD printer. not an LED

There are generally 3 ways, in order of least to most desirable, and at times you need to combine them in an escalation:

Toss the vat. This is the most expensive and generally should only be the last resort, for example, if you damage your film.
Careful Brute Force. This can damage the film, but carefully getting a wedge between the film and the print might be the only option to remove the last bits sticking to the film. If you have to resort to this, take your time.
Using thermal expansion. We all know that materials expand when you heat them. The reverse is also true: materials shrink if you cool them. Different materials shrink differently. So by cooling the vat with as little liquid resin and the print inside can lead to the print 'popping' free, just like in an FDM printer. Note however that this might not work on its own in case you made a suction cup (then you need to resort to brute force or drill a hole into the top), and you should take extreme caution not to contaminate any food with resin, as the stuff is not safe for consumption at all. With the right setup, you might be able to heat the build plate carefully while the print itself is kept cool.

The freezer works, and I have a plastic box I use to avoid food contamination, courtesy of my better half. I am going to try compressed air next, as a way to bring thermal expansion.

actually you'd use cooling-contraction :)

I found another convenient approach: while rinsing the print to remove residual resin, I wash the print with cold water, and immerse it in the same in a takeout-food box dedicated to the purpose. I then rinse the printing plate with really hot water. The difference loosens the print enough to make its removal much easier.

@0xF2 oh my! That's thermal shock too, but different direction!

I don’t think compressed air is going to change the temperature of your part, unless you know different.  Do you expect the temperature to go up or down?

@Frog compressed air can act as a coolant

@Trish It can, but only if the air is cooler than the object being cooled, or in a situation where the air pressure is dropping, such as a venturi.  I don’t think that’s what the OP is proposing

@Frog well, in most cases the air pressure of air coming from a compressor has the pressure dropping form.. 2 bar to 1 bar, meaning it usually cools rapidly. heating with compressed air can be done if you have the air carry some kind of granulate (sandblasting) which then transforms a lot of kinetic energy into heat energy in the part

That is true, but the kinetic energy is partially converted to heat as the air meets the surface.  It’s not an effective method of cooling in this context (i.e. lowering the temperature of an object significantly below ambient.

@Frog depending on air pressure and impact angle. As said, it can, but is not always.