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Bricked Mks Rumba+ Board after Power Supply Trouble
This is my first time posting on this forum, so bear with me:
This is my first attempt at a RepRap project, and my go-to board has been the RepRapDiscount MKS Rumba+ since I wanted to have functionality with the Makerbase TFT28 Touch-Screen Display. The printer that I have been converting is a 3D Systems Cube 3rd generation. I have successfully modified the printer to accommodate my board and electronics, but have had many issues finding a power supply up to the task of driving the steppers and the heaters (my most recent attempt was using the Makerbase PWC 2.0 auto-off module
I followed all of the connections to the letter, looking at numerous forums to verify everything was correct, connections were very tight, modifying the original supply cord. My printer powered up and everything functioned properly, except there was no way to turn it off after initially turning it on (M80 and M81 had no effect). I read on the above link that I had to change my value on PS_SUPPLY to 2 and add a PS_ON_PIN in Marlin (not sure to which one on a Rumba+), which I was to perform. However, when I tried to upload my revised firmware through USB, for whatever reason my USB port was not responding at all when I plugged it into my computer (it doesn't show up in device manager anymore either, which is strange since I was able to upload an updated firmware sketch less than a week ago), although everything that was previously on my board was still there, and hence I had a functional printer board.
Unfortunately, I convinced myself that in order to make the changes I needed to get my PWC module to work as intended, I needed to get the updated firmware onto the board somehow. So I looked up forums regarding the original Rumba (I couldn't find nearly any regarding Rumba+) on how to program it through using a USBasp programmer, which involved converting a ten-pin ribbon cable to a six-wire ISCP connection on the Rumba+. I paid extra-close attention when wiring these, following a diagram outlining where to connect each of the six wires detailed in the following YouTube video at 4:25.

I then selected "USBasp" as my programmer, and attempted to upload this way. I could see my Rumba+ responding, which gave me hope, but then the upload failed. Unfortunately, as I was to later learn, uploading via ISP also undoes the bootloader pre-configured into the board; and thus, I also managed to brick my board amidst all of this trouble.
I have been searching every forum possible, reading about ten Instructables on how to undo a bricked printer board (none for Rumba+, but for other ATmega2560-based boards, so I tried to work off of them). (I have since removed my power supply). I have used both my USBasp and my Arduino Uno as ISP, and tried using the guidance provided by Nick Gammon at http://www.gammon.com.au/bootloader, which seemed to re-download the bootloader according to the sketch, but all of my attempts to re-upload the Marlin firmware have still failed. My most recent error has been:
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer

In my experience, this error has been very vague in what it entails, and I'm inclined to believe that my USB-to-serial ATMega16U2 was damaged when I powered on using the Mks PWC (I suspect this because I don't recall any issues prior-to using the MKS pwc), though I read that the Rumba board does occasionally have this issue at random. My question is that am I on the right track in trying to restore my board through ISP via my Uno and/or UsbAsp, or is my board damaged beyond repair and unuseable? I can live with not having a serial connection to my board via USB (since I have a wifi module for my TFT28 display), I just need to find a way to get Marlin back onto my Rumba+ (I will resolve the power supply issues later).


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Creality CR-10 problems with extrusion while printing
I have an extrusion problem with my creality CR 10 3D printer while printing.
I am using a standard 0.4 mm nozzle with a 1.75 mm diameter PLA and I use Cura as my slicer.
This printer worked perfectly fine and I stopped using it a few months ago right after the problem started.
When I try printing a .gcode file, the first layer is very thin but visible (it seems like the glass bed is engraved). However, after the first layer is complete, the extruder stops working properly. It moves forward then jumps backwards so it looks like the filament isn’t moving (I can also see the extruder’s marks on the filament). Also, the axis seem to move fine in all directions as I’m able to see a clear first layer.
However, when I go into the “prepare” menu of my printer and move the extruder, it works great as the filament flow is very smooth.
Hence, the problem is only visible while printing. I don’t think there’s a problem with the .gcode files as I printed them perfectly fine beforehand.

It looks like your nozzle is clogged. You need to perform a “cold plug“ (google it).

Please provide photos of the problem!

Without images of the problem it is difficult to diagnose, but, the described symptoms sounds as if the nozzle is too close to the bed. If the nozzle is too close to the bed, and the extruder not strong enough, the filament flow is very limited due to pressure caused by a very small opening between the nozzle and the bed. Skipping of the extruder may wear out (grind) the filament and stop extrusion altogether.
Re-level the bed with a (thicker) piece of paper or with a feeler gauge. Alternatively, increase the height of the nozzle by re-defining the height or add an extra Z raise in the slicer (see question: "How can I add an offset to the first layer to increase clearance?").

"Re-level the bed with a (thicker) piece of paper or with a feeler gauge." The CR 10 has an automatic bed level system. When in doubt, run that program. The Z-adjustment is located near that option.

Clearly you're having an extrusion problem. Extrusion problems usually come either from a clogged nozzle (as @Adam S. said) or from the extruder it self. To determine where the problem is located I would first do a flow rate test using this. When doing this test you can determine if the extruder is grinding the filament or if it's not grabbing it too much. After the calibration of the flowrate you can be certain that the printer is (by .gcode) pushing the correct amount of filament. If the problem persist I would first do an unclogging (since it's cheaper than the following option) using something like this.
If both previous options do not solve the problem, I would highly recommend you to by a mk-8 like metal extruder. After a while, the plastic one that comes with the printer loses force and you'll lose steps. Personally, I had a similar problem where the first layer was printed in a droplet pattern and was solved by changing the extruder to a metal one.
Try these options and if the problem persist you could upload some pictures of the first layer or a video. Other possibilities I think of are that the filament is having trouble passing through the Bowden tube or maybe you'll have to reasemble the hotend.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

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Nozzle jiggles when screwing into heating block
I've had the Ender 5 Pro, as is, for 3 months.
After I tried a cheap PLA filament (maybe too cheap), it clogged the nozzle. I cleaned it, but any other filament I have would have similar problems from then on. After some days doing test prints, it clogged again. This time, I heated it up to 240 ºC, I unscrew the nozzle, cleaned it up, chopped the Capricorn tube (it had clear symptoms of a previous tube not reaching the bottom of the hotend and leaking material around it), perfectly aligned, cleaned the heating block with a brass brush, started screwing the nozzle… and it never reaches the end. It even jiggles a little bit (by "jiggles", I mean that when the hotend is hot, you can push the nozzle back and forth, and it does move... like it was a joint, and not a threaded bolt), like it was too small for the block. I try screwing a new nozzle. Same happens.
To me it looks like the heating block thread broke, but I can't be sure. I tried a thicker nozzle (0.8 mm, but same thread in the end) and it worked. I could feed filament and it wouldn't look like clogged (at least for 15 cm of feeding filament, when in previous cases it was almost instantaneous).
Time to get a new heating block? Any recommendation?
Would another kind of heating block be better?
Edit: Here's a picture of the bottom of the heating block. Now it's clear there's a metal chip glued with material, and almost (if any) no thread at all.

Another question. Could it have been that cheap material that caused the clogging, or was it just a lack of proper maintenance?

By "jiggles", do you mean you can continue turning it indefinitely without it stopping, or just that once it stops, it's not rigigly held in place. I think you almost surely have damaged threads in the heating block, possibly with just barely enough working to hold some nozzles but not others. Can you get suitable light and camera angle to take a picture that would let you look at the threads? This would likely be the best way to confirm. If they are damaged badly enough not to hold a nozzle rigidly, you should replace the heating block, but there might be hacks you could do to keep using it.

You need to order a new heating block (just a few bucks/euros, so order 2, and spare nozzles, you don't want to install the old nozzles), you completely worn out the threads, this is beyond repair. It looks as if you used too much force to secure the nozzle into place.
This is how it is supposed to look:

You can find these cheaply at those typical Chinese vending platforms or online marketplaces. Just search for and Ender / CR-10 heater block.
Typical dimensions are found below:

Thanks! Do you recommend also buying a new throat (or maybe the whole hotend straight away)?

@Korcholis Yes buy new throats also, always handy to have spares.

If the threads are damaged badly enough not to hold a nozzle rigidly, you should replace the heating block, but there might be hacks you could do to keep using it for a while until you're ready to replace. I've had luck replacing threads in completely unrelated applications with epoxy, and if you can get one that handles and transmits the heat well enough (maybe JB Weld? not sure) it might work here.
I don't think there's any indication you need to change to a different kind of heating block. That would only be indicated if there were lots of other people reporting the same problem you're having with your printer model or similar ones. It seems more likely that, if they're damaged, you just did it by over-tightening or over-vigorous cleaning with the brush.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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CTC i3 Y-axis thin / no filament deposition
I have this CTC i3 printer; when I print square test prints, as it moves along the Y-axis back to zero (front). It extrudes lines but very thin or none at all.
But opposite direction along the Y axis is 100 %

I can see a couple of problems in your images:

Your bed is clearly and awfully unleveled. Check on Youtube some manual leveling using a paper.
Though I think your problems will be solved by correct leveling, if not, check this thread where I explain a little bit about E-step and flow rate calibration. Having these parameters right is crucial for a good first layer.
I don't know what you are using for layer adhesion but if after doing steps 1 and 2 the problem persists I would heat up a little bit the bed and change the adhesion material (glue, hairspray).

Looking at the first image, it appears that the nozzle is a little too close to the glass build plate. You clearly see that the nozzle scrapes over the glass and filament is deposited on either side of the nozzle. Re-level the bed with a (thicker) piece of paper or with a feeler gauge. Alternatively, increase the height of the nozzle by re-defining the height or add an extra Z raise in the slicer (see question: "How can I add an offset to the first layer to increase clearance?").


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Face where there should be no face
When importing this .stl file in Creality Slicer another face appears in the middle when viewed in layered view. This face is not visible in my 3d modeling software Blender. I tried cleaning up the model a bit and to triangulate the faces myself, neither helped and the problem is still there. Also I didn't find anything online.

At the intersection of the top and bottom planes of the cross-piece and the cylinder, there are non-manifold edges. Meshmixer is able to identify this problem but cannot repair it. My slicer, Simplify3D also identifies the faults and prints a solid cylinder between the planes. Prusa Slicer 2 also creates a solid at that location.
As you've indicated that you are the creator, consider to use the 3D printing features within Blender to assist you with repairing the problem locations.

File ‣ User Preferences (or Ctrl-Alt-U)
  to open the User Preferences menu.
In the Add-ons tab, start typing 3d print into the search bar. Once
  the “Mesh: 3D Print Toolbox” shows up, click the checkbox on the far
  right to enable this add-on.
Close the User Preferences window.
In the Tool Shelf, there should be a new 3D Printing tab.


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FLSUN QQ doesn't print and stops at Z=15 mm
When I try to print something that is not the test model already on the SD, which means when I try to slice something in Cura 4 and than I start the print, the nozzle stops at Z=15 mm and only the extruder motor goes foward and backward. I tried to modify the G-code but I didn't solve the problem. I need help because it's my first delta 3D printer and I don't know what to do.

Can you add an image of your print and the stl image?

Did you use the pre-configured profile in Cura?

have you configured z-offset yet?

A distance of 15 mm is about the height of the probe or Z-offset. That can be a clue.
Compare the G-code from the testprint with the G-code you sliced. It can give you other clues.


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Dots in Cura on Prepare-mode
When I load a figure in Cura 4.6.1 I get weird dots all over my figure in Prepare-mode.

How come, and can I turn it off?
It's on every model I load :( I am fairly sure the normals are facing the correct way as well.

Solution found!
If Display model errors is disabled, the dots appears.
Check the setting, hit OK, click on the box and they disappear.


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Prevent raising Z-axis after homing
I've recently configured my Bigtreetech mini e3 v1.2, and I have every aspect of the printer running well except for the initialized homing sequence (the problem is sometimes small enough to where I can still get a good print). Originally what I was running into was that because I used two Z stepper motors, any movement that wasn't manual input on Pronterface would cause the motors to vibrate and make noise (not enough current). Now the only time the Z motors make noise/vibrate is right after the homing is complete and they briefly move up when the nozzle begins to heat, as well as right after the heating is done and the nozzle dips down to begin the print. I suspect it's because of a fast increase in Z speed that I don't necessary need. I've tried changing a multitude of settings in Configuration.h but haven't had any luck. Does anybody know the command that dictates the Z motors to very quickly move upward just after homing and before heating?

Just solved my own problem. Instead of looking in Marlin for the command, I found out the reason it was lifting up quickly was because of a custom command embedded in the G-code by the slicer. I got rid of the command and the problem was solved.

Maybe you could add some detail on the actual G-code command and the reason it got inserted by the slicer, that may help others facing similar issues!

I think I'm having the same issue any detail on the exact G-code would be helpful.


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How do I compress 3D files
I'm trying to compress different 3D files, but find it difficult to find the right software to compress the file.
What are the most suitable 3D file compressors to compress 3D files like STL, OBJ and STEP?
I have tried Draco, and mac zip compressor.

These are all binary formats, I believe, which generally don't compress well.

Technically STL can be either ASCII or binary. Although the latter is a LOT more common. But even the binary STLs compress pretty well actually.

3D files differ greatly in size and what they contain:
STL
STL Stereolithography files were invented by 3D Systems to store surfaces. Originally it used ASCII text to store information by naming triplets of vertex positions for each triangle (facet). Since that got too large, newer STL are Binary, which is quite smaller.
Many programs can export them, their size is dependant on the number of surfaces. You can reduce the size of an STL by lowering the number of surfaces at the cost of detail.
OBJ
OBJ was invented by Wavefront as a means of storing 3D information. It stores the data as plain text by storing vertices, to which they connect and what texture is on surfaces spun up by the vertices.
In comparison to STL, they can be bigger if they include surface information. Programs that can't do STL usually support OBJ. Slicers take either. You can reduce the size of the file by reducing complexity.
STEP
STEP files don't save 3D items per se, they store instructions for CAD programs to generate a 3D item. This makes them extremely information-dense and can create highly complex items with a somewhat minimum of file size. They also allow us to easily modify the file.
However, STEP files can't be sliced directly and need to be opened by a CAD program.
Comparison

This is a simple object generated by a mere extrusion, rounding corners, extruding again and a sweep, then copying the item and moving it into position.

But how does that compare as STL and OBJ? Well, the results of this item are rather small in either case, but you get a rough gist of their general comparability.
The STL is 74.3 kB, STEP is 90 kB, OBJ is 95.4 kB.

However, in a maximum compressed .zip archive, things change a lot:

STEP shrinks by 86 % to 13 kB
OBJ by 84 % to 16 kB
STL by a mere 73 % to 21 kB.

Conclusion
STEP is the best to give out in a zip archive if you want others to edit it. OBJ is a tad smaller in a zip archive than STL, but also can contain additional data.

If a general-purpose compression tool using a good compression algorithm, such as 7zip or gzip (for linux and command line enthusiasts) is not providing good compression it is not likely that your files can be compressed very much.
This applies to a wide variety of binary files beyond just 3D print files. There is always  a fundamental limit on compression (since it works by finding patterns and removing redundancy in files), and well-designed binary file formats generally can't be compressed very far.
You may however have some luck with changing the settings on your CAD tool to output less detailed files (though you this is obviously a tradeoff.)


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Homing X and Y after stopping print through display
How can I include homing X and Y  of a Marlin firmware operating printer after I press the stop printing in the display?
In which folder I need include the command?

It's EVENT_GCODE_SD_STOP in the configuration_adv.h file.
It appears to have been added to Marlin 2.0.x on 2019-04-03.

Maybe you can expand the answer, to include whether it is possible to include the command(s) in a file as stated in the question.


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Optimum ratio of line width to layer thickness for overhang performance?
When I have overhangs in my model, Cura colors them red. However, I noticed if I make layer thickness thinner, the red area is reduced or disappears.
This could mean that thinner layer thickness is better for overhang, but it could also mean that a larger ratio of line width to layer thickness is better. It makes sense that if line width is 4X the layer thickness (such as 0.15 layers with 0.6 line width), overhang performance should be better than if line width is only 2X (such as 0.3 layers with the same 0.6 line width.
Is there a model that explains the optimum ratio of line thickness to layer height? Is only the ratio important, or is layer height also important by itself?

A wide line works if there is something below it to squeeze the filament against, but if you don't have a full layer below it, it will stay thinner and it will droop. I would not use extreme ratios on overhangs. Still, do a parametric test: a overhang tower (a compact one) at different line widths and layer heights. If you test 3 layer heights and 3 line widths, it's only 9 short prints.
However, as you can see in filament reviews, different materials behave differently. I think there is no a priori optimal value.

Cura high-lights overhangs in red if the printer would end up printing completely into thin air.
If your overhang is angled instead of being a purely vertical-to-horizontal transition, a much thinner layer height can increase the chances that enough of the prior layer exists to support the next layer being printed.
Basically, the thinner the layer (within reason), the greater the allowable angle of overhang that is safe to print.

In terms of Cura's model for showing overhangs, I'm nearly sure it's just the ratio - rise over run, or rather run over rise. And indeed that's what makes sense mathematically:
At least some portion of the wall extrusion in layer N+1 needs to sit on top of the corresponding wall extrusion in layer N. For a given 3D surface slope, the "run" - the distance the cross-section moves from one layer to the next, which needs to be bounded by some fraction of the line width - varies proportionally to the "rise" - the layer height.

In that case, there seems to be little downside of maximizing the ratio. Are there any other downsides of wide lines, but thin layers? I think for me with a 0.4mm nozzle, that 0.1 layer and 0.7 line width would be the practical limit--a ratio of 7.

You can't actually make lines wider than your nozzle width without something to press down against under the nozzle orifice. You'll just extrude the nozzle width into thin air.

I routinely use 0.7mm line widths with my 0.4mm nozzle. I think the limit is related to the size of the flat area at the end of the nozzle. Sadly, nobody seems to specify the diameter of the flat area of nozzles, though it would seem to be a relevant parameter.

You can use 0.7 line width fine as long as there's either bed surface or existing printed material under a decent portion of the nozzle orifice. You can't when the nominal line only overlaps the one below it by 0.15 mm because there's no surface below the nozzle orifice to make the extrusion spread out to 0.7 mm. It'll just extrude 0.4 mm into thin air. Essentially, line width greater than nozzle size makes at best minimal improvement to ability to print overhangs

I have an open feature request for Cura that could improve this and allow printing near-arbitrary overhangs, but it's unlikely to happen anytime soon. https://github.com/Ultimaker/CuraEngine/issues/1215

The need for something on which to squeeze the new layer is the reason for the slicers to completely ignore line width on unsupported bridges, which assume a perfectly round extrusion, as wide and as thick as the nozzle (more or less).

@FarO: Sadly they don't do this correctly at all, which is why unsupported bridges end up being a bunch of loose strings on the first layer or two...

@R..GitHubSTOPHELPINGICE are you sure? in PrusaSlicer you can see that the line width changes for bridges. And if you tune bridges, they usually need very little flow rate compensation. https://www.youtube.com/watch?v=M0kkCw7LGhk If it doesn't work it's more likely that parameters are not optimal: https://www.youtube.com/watch?v=4KAMFamy3zw

@FarO: Cura has that too but it doesn't do the calculations right. If the layer height is 0.2 mm but you have an 0.4 mm nozzle, extruding an unsupported bridge requires more than the nominal extrusion amount to make the lines 0.4 mm wide, and they still won't bond with one another even if you adjust the flow up that much. They'll also interfere in the space below that's supposed to be empty. To do this right, bridges would have to be compensated by lifting the nozzle (essentially starting with the second layer or third of theb bridge), printing lines closer together than the nozzle width,

and adjusting the flow. Doing this all by hand for the layer height in effect is tedious and error-prone. Aside from the lifting part, I think it can be done with current slicers, but it's not automated at all.


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Still got poor printing quality after calibrating my Anycubic Predator
I've got an Anycubic Predator (aka Anycubic D). I followed the official instructions and leveled my printer.
The first annoying problem I ran into is that after the auto-leveling, the level test printing shows that the printer wasn't leveled at all. I tried about 4-5 times, and finally leveled the printer (I thought I just got lucky).
The second problem that isn't solved is that the prints I get are of poor quality. Shown in figure 1 and figure 2. The cube should be 20x20x20 mm, but what I got here is 19.6(x) x 20.4(y) x 20.5(z) mm.

Figure 1 - X-Y (side) view of calibration square

Figure 2 - Z (top) view of calibration square
Does anyone have any idea about how to improve the printer's printing quality? Thanks in advance.

A few tenths of a millimeter are pretty common for 3D printed parts; these are related to the printer hardware. These inaccuracies can be exaggerated by over- or under-extrusion; e.g. if too much filament is extruded, it increases the outer dimensions (and decreases the inner dimensions of holes).
The images show some signs of over-extrusion, maybe a little too hot also.

It also looks like it wasn't printed very finely, as in, the layer height is pretty big, like a 0.2 or 0.3 mm layer height. The layers seem fairly coarse. When I printed the same cube on my printer at 0.1 mm, the layers were nowhere near that jagged or stepped (like you see in the Y and X faces of the cube). Printing at a 0.1 mm layer height might produce a lot better results.

Yes. Not very finely. The layer height is 0.2 mm. I tested my estep, it turns out it is actually under-extrusion. Maybe the temperature? I'll try to decrease the temperature and print another one.

I assume you just assembled it.

Check the grub-screws in your pulleys at the top (remove blue covers). They are often too loose or even lost, causing a slipping belt.
After that, check your belt-tension, not too loose not too tight and the same for the three towers.
Also check that the wheels are not tightened too much.

It is actually best to break down the three towers and reassemble them carefully.

It might be a good idea to verify that there is a minimum amount of backlash in your system.  With the hotend cold, home the printer, and then using your fingers try to move the effector in all six directions (up, left, right, forward, back) and note if there is any play.  There should be as close to zero as possible.
If there is any play, then figure out where it is coming from.  Check that the pulleys are firmly screwed to the motor shafts.  Check that the carriages cannot wobble, and adjust the eccentric nuts if necessary.  Check that the belts are reasonably tight and all have the same tension.
Usually the universal joints in the arms are OK on a new printer, but they tend to wear and become loose after a while.
Note: I build and sell replacement arms for the Anycubic Predator, which use zero-backlash, magnetic ball joints.  I had this problem on my first printer, and magnetic ball joints solved it.


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Can UV cure inside opaque or more massive printed object?
From what I understand, UV curing of resin prints works by starting a chemical reaction that hardens the resin permanently.
Also, a curing step after print is needed to speed up the print and also to reduce the curing during print, which would cure resin beyond the current layer.
However, what is the transmissivity of UV light in partially cured prints? If I print a more massive object, or if I use an opaque resin, how deep will the object harden properly? Absorption is always exponential, meaning that it decreases quickly with depth.
Depending on the resin, how thick prints can be effectively cured? This information is not provided with the resin, which I actually would expect from reputable manufacturers.

My background
I am not a polymer chemist.  I know some, and I've talked about UV curing resins with them.  These are my conclusions based on that informal education.  Your expertise may well be better.
Minimizing curing on the printer is good
For the maximum print rate and best layer adhesion, the resin should cure during the printing exposure the minimum amount that is consistent with the object supporting itself during the print, being removable from the bed, being rinsed in isopropyl alcohol, and stand on its own during curing.
If you are curing too completely during exposure, you won't get optimal mixing of polymer chains between layers.  The layers will be attached by the glue-like action of the new layer on the old, rather than having their polymer chains cross-linked and extending between layers.
If you are curing too little, the object won't be strong enough to support itself and survive post-processing.  Soft, gummy bits may dissolve, or be swept away by currents in the cleaning solution.  Small details may not be robust enough.  Supporting structures (as added supports or parts of the model) may not be strong enough to resist gravity and handling.
If you are curing too completely, your print will take longer than it could take.
Curing is not binary
Curing will take place spontaneously over a long time.  If it didn't, a bottle of resin might last a very long time.  But, curing is not a self-catalyzing process that runs quickly to completion.  If it were, then the first stray UV that came through an open bottle top would turn the contents solid.  If exothermic (which it seems like it must be), the bottle would get hot.
UV curing may fail
UV curing the inside of a large, opaque object probably doesn't happen.  Before I get all excited, though, I would need to place some bounds on "large" and "opaque".
Absorption of UV light depends on the pigment or dye used in the resin.  This absorption is never absolute.  It is not 100% gone after the first, thinnest penetration.  The light is attenuated by an amount per distance it penetrates.
Transmission is the complement of absorption, and the numbers are easier to work with, so lets work with transmission factors of T rather than absorbtion factors of A.  $T=1-A$
If a factor of T is passed for millimeter, then one centimeter into the object the light intensity is $T^{10}$ of what it is on the surface, which is a small, but non-zero, number.
Keep in mind that opaqueness depends on wavelength.  For example, Window glass is transparent (very little absorption) to visible light, but highly attenuating to UV light.  Were I to design a black resin, I would look for a black pigment that was relatively transmissive to UV.
Will it cure?
A low UV dose delivered to a 0.2mm layer of resin will partially cure the resin.  1 mm into an object, the dose is lower, but it still exists.  1 meter into the object, the absorption is probably too high pass a useful level of UV.
If the transmission factor is 0.8 for a 0.2 mm layer, it is $0.8^5$ for a 1 mm layer (0.33).  It would take only three times as much UV exposure to cure a 1 mm thickness as a 0.2 mm thickness.  If the object were 1 meter thick, the transmission to the inner bit would be $0.8^{5000}$, which is a very tiny number, roughly $2.82×10^{-485}$.
Finally, consider if the object is or must be truly be solid.  UV curable resin is relatively expensive.  Many UV printable objects include drainage paths for uncured resin to flow out of the object during printing.  Perhaps your object could similarly be hollowed out.

The question was generic, but of course the implications were: attainable strength and reasonable amount of hollowing. What would be nice is to get some reference values for some common resins. I mean, getting UV only 1-1.5 mm in the object would be quite bad.

From what I know about the various resins, once they are printed they are cured enough. Some of the transparent ones require additional curing, however the manufactures of the machines only test based on the max size that their machines can print.
The resin never stops curing apparently, going into diminishing returns; curing slower and slower as time goes on. Only way you will know for sure is by experimentation. You should get a poly-carbonate tube, place black tape along one side then spray paint the rest black. This will leave a window that you can use for future observation. Seal the bottom, and pour in uncured resin. Leave it under a UV source for 2 weeks then peal the tape off to see how much of it has cured. Then come back here and ask Trish to do the math on what the co-efficients of absorption are for the material :)

I thought that after lifting them from the vat they are still flexible. Maybe it applies only to transparent ones.

Meanie to let me do the math! I point to the Penetration depth formulae and Beer-Lambert's laws: photons penetrate to some degree dependant on the energy of the light and the material structure penetrated. An article that popped up with the relevant keywords is this but I have not yet read more than the abstract. Note that the paper used gamma ray and polymers that substitute ...

tissue - the material closest to the resin might be the nylon and water substitute. While not a good analogue, note the general shape of the graphs, which shows the general behavior of high energy photons in matter - little interaction till some depth (mean free path, MFP), then a huge peak and then a falloff of energy deposition. This can be altered by altering the energy (=wavelength) of the photon beam and depends on the material...

@trish at the energy levels of the UV, I think thus would behave more like light than gamma rays -- more driven by scattering and diffusion than particle interactions.  The energy is more like vibrational energy than ionization energy.  The activator is special in that it is the path between these low energy photons and the creation reactive radicals.

@cmm Gamma radiation is light of 10^19 Hz/100+ keV. UV is 10^13-10^16 & <100 eV. Between the two lies X-ray, but all the 3 behave exactly the same but for the energy and free lengths shifting around. Gamma radiation, X-Ray, UV and visible light, just as much as microwaves and radar are all the same: LIGHT. It's the amount of energy deposition that acts either ionizing (gamma) or heating (Infrared). Lifting an electron to a higher level to make the atm more reactive is technically ionizing!

I mainly linked to the article to show the pattern: to deposit the energy in the material needed to start curing, there needs to be several factors given: The energy of the wave needs to be in a specific, material dependant band. The Mean Free Path has little to no influence on the position of the energy position, but the larger the MFP, the faster the energy deposits, telling us a density dependency of the process. The main interesting chart is on p.123: The 15 keV = 0.826^-12 m = 362*10^18 Hz chart shows us a huge dependency on the material for penetration depth.

Trish, I may be wrong, but I think there are several mechanisms at play.  One has to do with lifting electrons to higher energy levels, one has to do with having that life be to such a high energy level that the electron is functional free from the atom, but another has to do with adding energy to vibrational modes of the atomic bonds, which is not an electron process.  You probably know the chemistry.  What exactly is changed by the UV light?  I strongly suspect it is a bond change, I am often wrong.

Would Autoacceleration affect the polymerization rate any?


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Sketchup Free STL import in FreeCAD not working with Fasteners Workbench
Hoping to get some help with something I'm trying to accomplish. Unfortunately, due to my being a noob with 3D modeling in general, I'm coming here for hopefully more direct help.
Env. Details: OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13541 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 9948ee4f1570df9216862a79705afb367b2c6ffb
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)

Essentially, I have a need to design some housing for a small electornics board. Due to the nature of 3D printing being less than ideal for bending/snapping locks, I've decided to use small screws to hold multiple layers of housing together.

SketchUp Free proved to be a super intuitive, easy to understand 3D modeling software, tho is limited in functionality due to paid tiers.
Unfortunately, FreeCAD felt like a confusing cross between early 2000s Microsoft Paint and Eclipse (Java). However as the open source alternative, I understand it's incredibly powerful and can/should be able to do what most 3D modeling software is capable of, if you know how to use it properly - and that's where my lack of understanding shines through. Research into my use case revealed a plugin (Fasteners Workbench) which seemed purpose built for dealing with screws/threads, and I greatly prefer this approach due to being able to select standardized sizes.
On to the problem:
I decided to sketch out the main design for the housing in Sketchup, and am happy with it, though I am missing the holes in the four corners. To add this, I decided to export the file from Sketchup as STL and import it to FreeCAD. Once in FreeCAD, I switched to the fasteners workbench and created a screwtap of arbitrary length. Now, from most tutorials I've watched, removing one piece from another is a boolean operation, often a cut or an intersection. However, when I highlight both the part object and the screwtap and select the CUT boolean operation, what I expect to happen (the screwtap was "cut" or carved out of the part object) did not.

I'm wondering if:
- My understanding of the boolean operation is wrong. There is a different function that is used for "boring" threaded holes?
- My process is wrong. Does exporting an STL from sketchup free not work for certain operations when importing to FreeCAD?
- My models are off. I have an understanding that "grouping" parts of models is big when putting a model together from parts, so as to simplify life. I'm wondering if it's also required in these cases? Attempting to do the boolean operation in sketchup failed but did require having grouped components. I'm not sure this is the case in FreeCAD, or if I'm already doing this?
Would appreciate any help with this. Attaching the FreeCAD file here.

Note that you don't need to insert a hole with threads, it is far more easily to a) make a little smaller hole than the screw and tap the threads in, b) use knurled inserts (this is my preferred solution). Also note that threads in plastic wear out pretty fast.

If you tap plastic, use a fine thread if you can!

Stls may not properly import as solids.  This is likely what is happening in your case.  Stl format is ultimately just a bunch of triangles without a proper definition of a solid.  The boolean Difference found faces to attach to the circle so it used them.  The trouble is, there were even more faces at the same location (not uncommon).
You could manually delete and repatch the triangles in Mesh Design or if the shape is simple enough (I think your box fits the bill), redraw it.  I don't know how far sketchup has come with file formats, but a different format may convey your solid better between software.
That said, in your shoes, I'd be making cylindrical and hexagonal cutouts and gluing a nut into my part.

There are a number of steps to importing an STL file into FreeCAD and being able to use it.
This page discusses this in detail, but to summarize:

Import the STL
In the Part workbench, use Create shape from mesh.
Use the Advanced utility and select Solid from shell.

Now I will tell you from personal experience, you still may not be able to what you want to do. FreeCAD really isn't designed to work on STL files and really isn't the right choice.
Good luck.

I have been down that road with FreeCAD and STL files and never ever succeeded. I actually use Prusa Slic3r whenever I need to edit STL files such as resize, cut or split and object.
That said, FreeCAD is extremely powerful when you learn how to use it. It took me several months to get a good workflow with part design and the ability to write scripts/tools with Python opens up a lot of possibilities to automate various tasks, especially when interacting with 3D printing software.
I would recommend starting with some tutorials in using part design and the sketcher. Your design is very easy to redo in FreeCAD and if you are making many different enclosures, all dimensions can be put in a spread sheet inside the FreeCAD project and referenced wherever a numerical constraint/constant is used.
That makes it very easy to parameterize a design so it can be reused in various projects. I have for example a parameterized thread that I use to print parts that can be screwed together with printed threads or using standard M-thread screws directly in holes with printed threads.


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First layer rippling and no filament in certain areas
I'm new to 3D printing and I noticed some problems with my print.
I've printed it 3 times and releveled the bed. Now, I found that the right lower corner always has holes,

and some stringing problems

Lastly, the place where there should be a full line suddenly becomes string-like, and it always happens at the same place.

It's like my extruder pulls out the filament or fails to create filament in the area that should be filled with filament. Is it normal or did I set my printer wrong? I'm afraid it might cause holes in my new print.
There's also some stringing problem that causes the layer to be uneven.
Slicer: Cura 4.6
Settings:

My printer is Anycubic 4Max Pro

Please share what slicer you're using and relevant settings, especially speed, retraction, and temperature. Since you mention stringing, that's likely the root cause of the underextrusion in the corner there - any stringing is material lost in one place that then doesn't get deposited in the place it was supposed to go, and it's usually caused by wrong retraction settings (wrong = off or too low, in most cases).

Anycubic 4Max Pro appears to be a direct drive printer (extruder motor is right on top of hotend). The 6.5 mm retraction on in your slicer settings is more typical of a Bowden setup, where the extruder motor lives off of the moving carriage, and has to move extra to compensate for slack in the tube to the hotend. Direct drive retraction distance is typically 1 mm to 3 mm. I bet you can retract faster than 25 mm/s- the speed matters. Also, 60 mm/s travel speed is quite slow. 150 mm/s is typical. Faster travel means less time to ooze.
Your initial layer print speed of 20mm/s is good, slow slow makes the first layer stick better. I don’t see your 1st layer thickness setting, but I have had good success with using a thick first layer with a chunky, wide line width (like 150% of nozzle size), even if the following layers are fine. The idea being that more plastic and height in the initial layer makes it less temperamental as far as bed leveling goes, and it holds together nicely.
The cobweb-like lines are from the Combing Mode setting in Cura, that ignores the retraction when traveling through infill. Unfortunately there is a setting that also ignores retraction on the bottom layer, you want to change that under “combing mode” it is set to “not in skin”, or combing is set to off.

I see this is an old post but I type anyway if someone else stumbles up in here with the same problem.
First of all, I have a Qidi X-max printer and it printed exactly as in the picture. I am not 100 percent sure because pictures don't tell everything. I googled it very hard to find people that had the same issue. I only find this but it didn't help me so much.
I took apart my printing head on the machine, it is built with a direct extruder. I found some screws were not tightened and the block was a bit loose. I could screw it in 1 whole turn. After that, I cleaned the gear for the extruder so all the old filament was gone. There was not much filament but better do it properly. After that, I screwed all back and it was gone. I can't say for sure what was the exact cause. But if I have to guess I think it was because of not having properly tightened screws. This problem occurred every time when it was starting a new layer. It was not squeezing properly from the beginning and after maybe 3-4 mm everything squeezing as it should. New layers and seams were affected by this. Holes at the beginning of the layer and holes in seams. I also tried increasing the temp and flow. Flow helped a little but not much. So check all the screws. The ones I found were holding the print head. If that doesn't help do as I did and see if that fixes the problem.

From the wispy horizontal lines within the perimeters in your second image, it appears that the nozzle is still oozing material during the travel moves. This is likely causing the hole in the corner and the wispy perimeters too. When the extruder reinserts the filament into the hotend after a travel move, it expects the same amount of material to be in the nozzle as when it extracted the filament, but some material has oozed out during the travel move so that is not the case. I had a similar issue with my printer, and was able to mitigate the problem by increasing the retraction extra prime amount in the material section of Cura. This should compensate for the material loss during the travel move by reinserting the filament slightly farther when starting the extrusion. This solution is not perfect as different lengths of travel allow different volumes of filament to ooze from the nozzle. If you want perfect prints, you may have to tune this to the model you are printing: larger models usually require larger travel moves which would allow more time for plastic to ooze from the nozzle.
If you try this, make sure to look for blobs at the start of extrude moves. If the prime amount is set to high, it can create blobs on the side of the model (or inside depending on which perimeter is extruded first) which could cause tolerance issues on more complex parts.
Personally, I have also added a small coast distance to the end of each extrusion (located in Cura's experimental section). This allows the nozzle to ooze into the perimeter of the part which should decrease the stringing on travel moves, and thus loss of material on travel moves.

This is all hacks to try to work around a problem that's entirely eliminated by correct use of retraction.

authors: роман чертов


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Use fixation holes instead heated bed
I think that heated bed have some disadvantages - they arent always reliable, they consume additional electrical power.
I can imagine one way how HB can be replaced - in some flat surface - glass or iron sheet we can drill some specific holes (probable a bit conic). Then, before detail printing start, printer could fill it with material and continue print detail connecting to these fixations. That can fixate detail in X,Y and probably even Z axis. After printing we can just take detail or cut fixations (if there were Z fixations)
I almost sure someone in industry already thought about this bud didnt release and I dont understand why. Defineteley there is pitfails,  but I dont see them. Why this method cant be used to replace heated beds?

the heated bed is to keep the bottom layers the same size as the currently printing layer, I don't see how your idea replaces that.

OK. Can we combine both methods? When we need more adhesion - use holes, when layer size - heating

I do not think this is a question fit for the question-and-answer format of this site. This seems more like an attempt to start a discussion on a novel idea.

It is a good idea, but this site doesn't support extended discussion.

I've used a 3D printer that had a perforated (and heated) bed for adhesion. It was some incarnation of the Up printer -- and this was several years ago (2014 or 2015) when 3D printing was very hyped but hadn't reached its present level of technological maturity.
(this was also before things like BuildTak and PEI sheet.)
The bed was made of a perforated fiberglass material similar to PCB boards (without soldermask or copper), black in color, and it was terrible. Prints were printed with a raft, which remained stuck to the bed holes and resisted all efforts to remove them short of a chisel or something similar, and before long all the bed plates (there were several) were marked and gouged from people trying to scrape plastic off of them. (they also warped).
I do not think that this is something we want to imitate, especially as it seems like Buildtak-like plastic coatings or glass work so well.
As to the use of holes alone to fix parts: They are going to be under stress, possibly too much shear stress for them to hold, you won't get the other benefits of heating, and you'll have trouble as you build upwards. For an extreme example, look at the difficulties of printing the insanely high temperature plastic PEEK, which basically requires not merely a heated bed but a heated chamber.


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Issues With Cura 4.6.1 Effecting Text Width On The Initial Layer
I'm have an issue where Cura 4.6.1 is effecting the width of certain characters if the part is orented to print them on the the bottom. The initial layer seems to be the only layer that is effected. It is also only effects certain characters, in this case characters 4,6,8 and 9. Picture 1 shows the part oriented to print text on the bottom. Picture 2 shows the same part oriented where the text is on the top, which results in the text looking correct.

I have looked for the setting that causes this but, so far, have been unable to locate it. Any help would be greatly appreciated.

The Brim setting was causing the issue.

Doesn't Cura have a setting to prevent generation of brim in "holes"?

Yep. It's called "Brim Only On Outside" (brim_outside_only).


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Can't print the top part of a circle
I'm trying to print the painter's tripod from this tutorial:

I can't get it to finish the print. It always fails towards the top when it's closing the circles. I've tried brims and even glue for adhesion, and different settings for inlays, perimeters, etc... my bed levelling is correct and my first layer is perfect. The prints come out beautiful, but they always fail there. I have a theory but since I don't have a camera set up I can't confirm, but I feel like the nozzle gets stuck against the previous layer, as if when it's coming from the other side of the "bridge" completing the upper layers of the circle, it get's to the other side of the gap and it finds that the filament has hardened just a bit higher than when it's going to print, and therefore knocks the piece to the side (despite using glue!!), and from that point on, obviously, total mess and I have to cancel. Just a theory though. Any ideas of what else could this be or what to do about it?
Printer is a Prusa i3 Mark3S

did you try support structure?

You are trying to print an unsupported edge up there - the top edge has nothing to rest on and thus sags down. As a result, the print failed.
To remedy this, activate printing with support. With a support angle of 80° or tree support, you could minimize the needed material.

This answer could be a lot more useful/helpful suggesting how to configure support for this model. It's likely to be a huge waste of material and hard to remove without tuning. I suspect "tree" support might do well. But classic support set for just sharp overhangs may work well too.

Hi Trish, I thought about that but i've printed circles before (not as big and not in a slanted plane, however) and I worked always fine. I always understood that the printer would be able to do the "angle" of the circle without the support, as opposed to a hanging 90deg corner. I'll give it a try anyway. Thanks

Added supports and printed like a charm. Thank you!


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Monoprice select mini underextrusion?
Can someone please review the picture and tell me things to try to fix, the threads are full of little gaps. The layers that are solid, below the threads have a tiny bit of space between them. Is it underextrusion, or a clog? The bottom layer seems good. Also I have taken a picture of grooves on the filament after the extruder. Is the the groove from the extruder normal?

The grooves (notches, more accurately) are acceptable and indicate that your hobbed gear has a good grip on the filament.
Many factors will cause your probably-correct diagnosis of under-extrusion. If you are confident that your extrusion settings are correct, you could have this problem from under-temperature on the nozzle.
One method to assess this is to increase the nozzle temperature by five degrees C and examine a test print. If the gaps are reduced but do not disappear, consider an additional step or two of five degrees.
If you are so inclined, locate one of the many temperature tower models and modify them accordingly for your printer. This will give you a good range of temperatures for best results.
Also note that different filaments will have different temperatures and the temperatures will vary between colors from the same manufacturer and between different manufacturers.

I have been using the same pla when I got the printer almost a year ago. I have switched slicers from cura to ideamaker since in the model view of cura, holes were shown in the model. It seems like only fine details are really affected. Is it possible that the nozzle is slightly clogged?

@NickSantitoro Maybe you should add print settings to you question, that may help in the analysis. Also, if you think that Cura is creating holes in the model view, this might be worth another question!

After doing some more research I have found out that as pla gets older it may require a higher temperature because of the moisture it absorbs. I have always used the same slicer settings, so hopefully this will solve the problem. I have also changed the extrusion width from .4 to .48. This may also help.

If moisture may be a problem here, you can bake it in the oven at a very low temperature (research the numbers) or use a cheap food dehydrator to push it out over a couple of days.


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Best/Simplest/Easiest way to secure a lid
This is a part I designed, a kind of a frame:

Into the frame I want to be able to place a flat object of variable (but uniform) thickness - like paper, glass, sheet metal, etc. The inserted object should then be covered by some kind of a lid and secured. The lid should keep the inserted object pressed against the "ledge" you see in the frame. The object in the frame will be repeatedly replaced, so the lid will be repeatedly taken off and placed again. When placed, the lid needs to hold, not fall off randomly.
What would be the best/easiest/simplest way to secure the lid? Considering ease of printing, so ideally no supports, as little additional separate parts as possible (but adding a few is not a big problem), etc. The side of the frame you see in the picture can be modified, stuff can be added.
Considered:

threaded inserts in the corners of the frame, screws through the lid. Screws are a little impractical. Threaded inserts for screws big enough to be practical when handled repeatedly take up a lot of space both in area and depth
rubber bands stretched from one side across the lid to the other side. Rubber bands seem a little weak to hold the lid securely, but I guess it could be done.

What methods would you choose?

Don't know how big your parts are, but if repeated use is a concern and you need pressure that screws can deliver, consider screwing on some toggle clamps if you have the real estate.
You could also make a 3d printed version of one that's sized to your needs.  There are some models available.

The toggle clamp base could easily be printed directly on the frame. Then I only need to add additional 3 easily 3D printed parts and connect them with some pivot axes (screws or rivets).
I don't actually need as much pressure as this could provide, I need security more than pressure, but a toggle clamp looks like it can supply that too.
It would be practical for the mounting solution to lie as flat as possible, but I guess I can design a clamp to minimize height. Probably need 4 clamps total, so in total 12 small additional parts.
Good idea, thanks! Will wait a while and mark the answer.


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Ender 3 underextrusion
I am a beginner in 3D printing and recently bought an Ender 3. With the filament included in the package, my first print ever was flawless. However, after the first print, I tried printing with ABS, which did not work out, so changed to PLA, and ever since then, all my prints were under extruded. I have tried everything. I bought a new nozzle to make sure it wasn't clogged, I cut the last 20 mm of the PTFE tube, I performed cold pulls, I leveled my bed before every print, made the line width in the profile 0.48 mm instead of 0.4 mm, increased the flow, tried printing with every temperature between 185-210 °C, looked at different Ender 3 suggested profiles on the internet, and more. I also made sure there was nothing wrong with the extruder. Attached are pictures of my most recent prints. Anyone who can tell me what I am doing wrong???

in what way did the ABS print fail? you might want to check the extruder mechanism and ensure it still bites into filament properly. shredded filament on the hobbed gear can cause unpredicatble underextrusion.

Have you found and fixed the problem? If so, has the answer below led you to the solution? Please vote to accept the answer so this question is not bumped up once in a while and can be removed from the unanswered question list. You may even add your own solution and accept that after 48 hours! If you have not been able to address the problem please update your question.

The Ender 3 V2 doesn't have this setting???

there are at least 5 large variants of the Ender 3 out there, and I have seen some 8 firmware distribution versions since I bought my first.

The helical exterior is an indicator of a filament diameter mismatch or volumetric mode enabled for linear commands
From ref:

Then you probably enabled volumetric extrusion by accident.
On LCD go to

Control
Filament
Disable
Save EEPROM
Revert estep cal if applicable.

What is it? M200
Its a feature of Marlin firmware which interprets E moves as mm3 instead of linear mm. It is poorly described in the menu, and tends to be enabled by accident.


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Printer froze mid print, stepper motor driver and MCU extremely hot afterwards. MCU seems dead now (?)
A strange problem occured while 3D printing. I've been printing for a long time now, and I consider myself fairly expeienced. normally, with every problem I've encountered with my printers (Anet, Ender, Prusa), there's always an answer online. However, the strangest thing just happened and I cannot find an answer.
I upgraded my ender 3 to a 32 bit BigTreeTech SKR v1.3 motherboard with A4988 stepper drivers. I've printed several objects successfully. However, on one simple print, it suddenly stopped working. the LCD was pale blue and flickering slightly. even after turning the printer off, moving the Y axis by hand felt stiff and erractic.
Turning the printer on resulted in the same flickering pale blue screen. Doing a power cycle did nothing. at this point, I noticed my MCU and ONE stepper driver was scorching hot (~100 °C) only a few seconds after start-up. I unplugged the Y axis stepper driver from the motherboard and suddenly the printer could turn on again (bootup sequence executed). All the controls on my menu still work (even moving of axes, as tested with working drivers). However, the reading on my thermocouples are all way off now, reading 55 ° Cat 30 °C room temperature. Note that the MCU was still scorching hot even when doing nothing.
Some additional info to note, the stepper motors themselves were warm while printing, but not unbearably hot. The Vrefs (current sense resistor 0.1 Ω) were tuned to supply 0.75 A to the axes and 0.9 A to the extruder. I also attached small heatsinks to the drivers and have a small fan blowing on them. I'm running marlin-bugfix-2.0.x. also, on the 4th last layer before the print failed, there was a very slight layer shift on the X axis. I've also reflashed the same firmware onto the board, but it's still hot enough to fry an egg. the board also can't connect to Pronterface anymore.
I can always swap back with the stock Ender 3 motherboard, but I want to know what's the reason for this tragedy so i can prevent the same mistake.

The reason for this tragedy is kinda outside the scope of the site. But basically BigTreeTech has been having some quality control problems lately. People on the facebook group have been reporting sudden deaths of their BigTree equipment. One fellow was able to find soldering issues with the board.

i see, thats unfortunate i guess...


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PLA Issue printing first 3 mm with Ender 3 Pro
I´ve tried tunning printer settings with different Nozzle(190-210 ºC)/ Bed(0-60 ºC) Temperatures, Fan Speeds (0-100 %), Cura and Slicer adjustemens but nothing worked. I still get the same bubbles in the first 3 mm of every print.
I also tried a glass bed and the magnetic bed that comes with Ender 3 pro and the result is still the same.
The last thing I tried was moving the 0 position of the Z axis 10 mm up, but it didn´work.
What else could I try? Any idea of which could be the issue. Thanks in advance.

Did you disable the fan for the first 3 mm?

No, it was enabled. I have tried different fan speeds to see it it affected and all the prints show the same issue. Do you have any idea of what else I could try? Thanks

This is caused by the nozzle being too close to the bed, try level with a thicker piece of paper or increase the height by redefinition of the Z level.

This answer hints to the correct diagnosis but doesn't explain how to fix this in Cura or any other solution other than babysteps. You don't want to adjust babysteps at every print...
Basically, your nozzle is too close to the bed (from comment 0.1 mm to be exact). To increase the distance between the nozzle and the bed you can:

level with a little thicker paper,
move the bed down on all corners,
move the Z endstop up,
redefine the Z=0 in your start code,
G1 Z0.1 ; Move to 0.1 mm height
G92 Z0  ; Redefine zero height
install Cura plugin "Z Offset Setting" from fieldOfView (through the Cura Marketplace) and define a Z Offset of 0.1 mm, and/or
increase the first layer height a little.

It seems like your bed might be too close to the nozzle, hence the large elephants foot (bulge on the first layer). You can try using babystep Z to increase the distance between the nozzle and the bed and see how that works out. I think you might need to reduce the flow multiplier (extrusion multiplier) a little too.

I tried to reduce the multiplier to 90% to see if it affects, but the issue is still there. It still has bubbles in the same layers.

@eltrompeta The multiplier does not help you like I mentioned, you could try to increase the bed to nozzle distance Harel mentions, that may help you!

I tried different babysteps Z and finally I got it right, but I found the best results adding a 0.1 mm babystep every layer in the first 1 mm of the print. In addition, I tried leveling the bed to increase the distance between the nozzle and the bed but the first layer didn't attach properly to the bed. Do you know if Z babysteps can be added automatically in cura since it's a problem that appears in every print? (or something that works in the same way) Thank you for your help.

i dont use cura, but there should be a setting for you to adjust the extrusion width. in cura it might be called "line width". normally, slicers allows you to set a different extrusion width for the first layer from other later layers. as to whether you can do that for the layers in the first 1mm... i highly doubt so.

your best bet is to tune your E steps/mm, bed level and extrusion width to fix the first 1mm. oh, in slic3r, there's also a setting called "elephant foot compensation". in cura it should be called "initial layer horizontal expansion". if it's set at 0, change it to a small negative value like -0.1 or -0.2

@eltrompeta You can add a Z-offset in Cura if you install the plugin of FieldOfView. But you can also redefine the Z height or re-level with a thicker piece of paper, or move the Z endstop up. If the answer didn't contain the flow multiplier hint it would be an upvote. :)


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

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

It looks mostly normal but you might have some overextrusion.

I would firstly do a flow rate calibration:https://www.thingiverse.com/thing:2490893
print this using: 0.2 mm layer resolution;0.4 mm layer width; wall count= 2; infill=100%
print it at the same temperature you printed the cat.
measure the walls width a couple of times in different places, get the average and then do : 100*0.8/average. the result is your new flow rate or extrusion multiplier.
I would then do a E-step calibration, use this:

Once you have this two parameters, re-print the block. I would suggest to print not faster than 50 mm/s and raise it by 5 mm/s if you see the thing is going right. Try a typical grid-20 % infill with 3 top layers and 1 superficial layer (usually you shouldn't need more than one). For these trials try scaling the blocks by 50% so you don't waste that much material. Try not to use the ironing function yet, you should get a uniform surface without it.
The weird thing is the holes pattern you get in all the pieces. Just in case, tighten your x and y belts, re-level your bed and try moving the extruder with your hand (gently) to see it doesn't wobbles.


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Levelling issues
I just got a Dremel 3D20. I unpacked the machine, and raised the bills platform as documented to setup the spool. Then I tried to level the surface and was able to adjust the left and right knobs but not the rear -- the knob came off completely, but the platform was not lowered. It was firmly pushing against the extruder.
I tried to print an object anyway and the rest part of the object was not forming properly as expected.
I cancelled the job. A few hours later, I tried leveling again. This time around the front knobs also started having the same problem.
I went to the jog mode in the settings screen, and lowered the platform, but it returns to where it was if I try leveling again or print another object.
Printing another object this time around is even worse because the platform completely fails to lower.
There's not enough documentation on Dremel's website.
Does anyone know what's going on?

Something similar happened to me during the firsts weeks of 3D printing.
I would recommend you to look for real case scenario leveling steps. Leveling is not that simple and sometimes user manuals don't even mention the many issues you may encounter.
Youtube is a great source of other user's experiences:

Just keep trying until you make it. Some people give up.

authors: Дмитрий Толкунов


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Filament that is resistant to ozone
Does a filament exist that can resist ozone (like certain silicone tubing's can). Most glass bottles come with tin or plastic screw hard tops and I would like to replace the screw caps with something that is more resistant to ozone.
The reason for this is I make my own homemade ozonated oil in glass bottles and I would like to print out different hard screw top caps for some of the bottles.

What about a coating? Either for your original tops or your 3d printed replacements.

@R..GitHubSTOPHELPINGICE It could work.  The original screw cap has completely fallen apart and rusted.  But if I print another screw cap with PLA / PETG and coat that part it could also work (as long as the screw cap can be closed)

You can also use a protective foil between the screw cap and the bottle. Just be sure it doesn't get torn when you screw/unscrew, but since it could be made of plastic, it shouldn't happen.

If plastic caps don't work out for you, you can get glass reagent bottles with glass stoppers.

You cannot 3D print it but you can make a gasket out of cork. It will hold well. And you can use any cap for that, just cut a round disk out of 2-3 mm cork. https://websealinc.com/technical-info/additional-materials/cork-gaskets/ Do not use PLA-cork filament, PLA does not resist to ozone. Or just use a normal cork from wine bottles...

If making your own caps ends up being the best solution, TPU (thermoplastic polyurethane) is probably your best bet. I don't have specific information on printed TPU filament and ozone, but TPU is widely regarded as one of the most chemical-resistant materials you can easily print with, and this page by Ozone Solutions rates polyurethane (no mention of specific types) A/Excellent described as:

Ozone has no effect on these materials. They will last indefinitely.

Being at least slightly flexible, TPU will also yield a good seal without any additional gasket. You should probably choose an unpigmented "natural/clear" TPU filament in case the pigments do react.
It might (probably would) also work to coat an existing cap with polyurethane. I'm not sure how you'd best get it to adhere, but lightly sanding the plastic then using a spray in multiple coats is what I'd try first.

This is highly relevant: PETG is very resistant to Ozone.
https://www.plasticsintl.com/chemical-resistance-chart

Link only answer. Please [edit] and add the chart to your answer. If the link dies your question won't be of much use to others.

According to https://www.calpaclab.com/polyetherether-ketone-peek-chemical-compatibility-chart/ and https://www.polyfluor.nl/en/chemical-resistance/peek/ PEEK is very resistant to ozone.
PEEK does cost about as much per gram as silver.

PEEK also requires a printer capable of temperatures over 370°C, which tend to be quite expensive or extensive mods to an inexpensive printer.

Does that make anything in my post inaccurate?

No, just likely less useful to OP and other readers.


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When do I need to get a BLTouch upgrade?
I've found many Youtube videos of makers upgrading to BLTouch sensor.
I have a Creality CR-10S Pro, so far bed leveling hasn't been an issue (after some days of trial and error).
My question is what are the problems/issues users need to face in order to need (or justify) an upgrade?

A touch or an inductive/capacitive sensor is useful when you cannot get prints to stick to the build surface because of a  skew bed platform/heated plate or if the plate has a bend, large concave or convex area.
Even with such a sensor, you need to provide a bed that is as level (trammed) as you can get. Automatic Bed Levelling (ABL) is not magic, it is just a tool that can help out if you have a problematic bed surface. But, recent versions of Marlin have "manual bed levelling"; i.e. you can map the surface using your printer without a sensor and store that geometry in memory.

Thanks for your answer. In my case, the CR-10S PRO, has a 'auto level' feature that you can include in your pre-print g-code. This means you can set different temperatures and run the auto level function before printing, it will add around 1 minute. So, I'm still not sure if the BLTouch would improve my printing.

@PhilippeDelteil You asked what issues you need to face in order to use an ABL sensor, so I've answered that. But indeed, if you have no problems with the first layer adhesion (from an irregular shaped build plate surface), it doesn't always add something to the printer. For some the biggest pro is the ease of use. I'm running printers with touch, inductive and no sensors, they all work fine! Sometimes it is fine to "Not change the winning team!".

I don't know your printer but I don't have BLtouch, and I have to set the height every time because the bed expands with heat.
If you print at variable bed temperature (PLA, ABS, PETg, nylon require different values) then that sensor helps a lot.
BL touch can also speed up bed calibration: you scan the bed, see the values to be corrected, adjust the bed without having to guess (given the thread pitch and required correction).
Also, if you print only in the center it's easy but if you print fully using the size of the bed, I doubt you can get very flat bed. The BLtouch helps for that too.
Also, there are clones like 3D touch which were tested and work equally well. Depending on your budget, they may be an interesting alternative.

Thanks for your answer. When I change filaments or temperature I just re run the auto leveling function of the printer. I'm using a mirror as a bed, it works much better than the stock bed surface.

@PhilippeDelteil how does the auto leveling works then?

Pretty much like this https://all3dp.com/2/auto-leveling-3d-printer-do-i-really-need-it/ . In my case I can add it to the beginning of the printing process.

authors: كمال الرويحي


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What's the purpose of the "outlines" around prints?

I am curious, what is the purpose of printing a single-height outline around the objects to be printed?
Also, how would it affect the outline if the object to be printed extends to (very near) the very edge of the print area?

Update, I received a hint that an existing question has the answer; that link was not really to my satisfaction -- but it did link to another one that did: What are main differences between rafts, skirts and brims?

Hi welcome to 3D Printing.SE! Note that this question is similar to "Random lines are being printed?", one of the answers discusses the purpose of the skirt.

It's a skirt, skirts are a method of adhesion. I print without usually, but for very thin objects I use a brim

Does this answer your question? Random lines are being printed?

Thanks for the update, but the question you linked does not describe all the benefits of the skirt, it is a good question from the beginning of the beta days!

I am curious, what is the purpose of printing a single-height outline around the objects to be printed?

The (equidistant) lines at distance from the print object is called the "skirt", the skirt is an option found under the "Build Plate Adhesion" options in your slicer. The primary function of the skirt is to get the flow going, but there are more benefits you can get from the skirt:

You can find out whether the bed is correctly levelled, or if the bed has concave or convex areas (the skirt should be a line, I prefer at least 2 lines, of consistent thickness, if not, this may hint to incorrect levelling;
You can find out if there is enough or a sufficient amount of adhesive (e.g. glue stick, hair spray, specific print adhesion sprays like 3DLAC or DimaFix, etc), if not the bed might be greasy or lacking the adhesion product;
You can configure the skirt height to use the skirt as a shield for draft or ooze and distance to product);

Also, how would it affect the outline if the object to be printed extends to (very near) the very edge of the print area?

Do note that a skirt limits the useable build area by the distance and width of the skirt.

Basically this has been answered (see this answer and this answer) in a different question ("Random lines are being printed?"), but it might be beneficial to answer this question rather than closing this for a dupe.  This question is focussed on the skirt, the equidistant lines around the print object, while the other question focuses on the priming line.

My understand is that's is basically a purging extrusion, so that you get flow through the extruder before you start printing the object, as filament that's been inside the hotend during warm-up might have been "overcooked" by spending too much time in the hotend at temperature. It also helps stabilise the PID loop controlling the extruder temperature by allowing the PID loop to stabilise the temperature of the hotend as it's got filament flowing through it compared to it being idle.
It also shows the user where it intends to start printing, which is a useful check if something went wrong with Gcode generation.

Aha, so based on your first paragraph, it might as well be shaped as a squiggle in some corner of the bed, yes? The way it is usually presented means the amount of purging depends on the area of the base of the model.

Exactly, the idea is that the printer purging line handles most of the purging of the "bad" plastic, and the outline is just handles the "temperature stabilisation", which scales with the model for probably no other reason than that the slicer doesn't have to figure out where it can put the purging lines (since there's never going to be a print outside the models on the bed).

It's also a good check of whether the print bed is level/at the correct height. I frequently make small Z babystepping adjustments while the skirt is being printed so it's in the exact right position when printing starts.

@KlaymenDK: Indeed, I find a prime line along the very edge of the bed far better than skirts. Every time I've tried enabling skirt, the inconsistent extrusion at the very beginning (from the nozzle not being primed yet) causes some material not to adhere right and get dragged around, and in some cases this actually messes up the beginning of the actual print! Doing priming as nothing but a straight line ensures that nothing can get pulled around before it starts adhering.


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Any defacto standards for controlling new tooling options on generic 3D printers (firmware control and signaling)?
Are there any defacto standards for interfacing between common 3D printers and custom extruders or other tooling? I was thinking how it would be good to have switchable nozzle widths mounted on the same heat block and switched between using a solenoid so you could have say a 0.25 mm for surface layer and details, then swap to 0.6 mm for the infill.
What would be the path of least resistance so it could be accessed in generic firmware?
The design I was thinking would be similar to a generic aluminium heat block with two nozzles screwed in side by side with there inputs meeting in an inverted Y junction with its center drilled out and replaced by a rod with appropriate channeling to divert the already molten plastic between nozzles. Turning the rod would be done from a solenoid mounted somewhere behind the heat-break.with a clamping mechanism.

you mean swapping the nozzles or whole printheads?

Just the nozzle

That will be challenging to fabricate a rotating/sliding mechanism. In firmware it is easy, just select the next tool and handle the tool change in the tool change script. But, I think this idea is outweighed by dual nozzle designs or tool changer designs. Actually, my Ultimaker 3E can already have multiple nozzle sizes. The only thing to do is to appoint the correct nozzle to the correct section to print (infill extruder in Cura).

Generally: nozzles are not changed, the whole tool head is
While "tool change" is easy to implement in a G-code and could be easily adapted in the firmware, there are several practical issues to hot-swapping nozzles without swapping the whole hotend assembly:

The hotend is a fluid-dynamic system that needs to be sealed to operate under pressure and temperature.
The seal of the nozzle-heatbreak system is in most systems a metal-on-metal pressure seal
Rubber seals are not an option in a system that runs over 180°C
Moving metal seals are very hard to make and run smoothly.

Your idea: especially No
There is literally no way to design a turning Y-switch that fits the following bills:

sealed
filament path ~2 mm
screw-in diameter for heatbreak and nozzles M6
creates enough free space between the lower outlets to mount 2 M6 nozzles with enough space to hold a wrench (=15mm diameter of centers)
fit into the form factor of a conventional heater block

Your idea would need to be considerably larger, need a stronger heater element and creates an impossibly to clean area around the turning junction peg. Atop that, you would trade 1 area of possible leak (between heatbreak and nozzle) for 3 areas of possible leaks (nozzle-block and heatbreak block) and one area of guaranteed leak (the turning peg).
How is it done then?!
Currently, there are the following ways to swap between different of nozzles mid-print that have been proven to work somewhat reliably:

fixed independent print heads with independent carriages.
fixed independent nozzles and heaters on one carriage.
swapping print heads on one carriage.

The first design is used for example in the Leapfrog Bolt, combined heads are for example the e3D Chimera, Cyclops and Kraken. e3D also designed on a reliable printhead - or rather tool  - swapping system starting about 2018 and did release it to the public in late 2019.
Type 1 needs you to level the printheads well and to the same height in the easy case, but with the right setup of firmware, a Z-offset of the two tools can be included and compensated for - possibly even automatically. Type 3 does usually demands you to include very accurate offsets of the used tools or includes a way to measure the offset during operation, though I lack insight into how e3D solves it. Both setups can mitigate oozing of the unused nozzles out of the printing volume.
Type 2 not only demands hyper exact leveling, but it also is very prone to create some sort of oozing of the unused nozzle.

Tool change is M06 (then some value specifying what change to occur). You will need to implement the necessary changes in the firmware to support whatever electronics is required to perform the tool change (eg stepper driver | hobby servo, mosfets to run the solenoid).
Once done, your slicer now has to do the work of knowing that there is a different nozzle size for different parts of the model. I know of no, slicer that can do that for different sizes on the same layer.
As for your idea: manual "tool changes" might be a better way to go, otherwise you would have to put the entire hot end on a carousel.
Proposed hot end ejection mechanism
The link (authored by me) describes a fast removal system for manually changing the hot end nozzles before prints. The electronics would need to be connected via pogo pins so that the installer doesn't need to connect any wires.
Further in this video (Printhead swapping), the author shows a magnetically attached and registered quick swap hot end, which can even swap the extruder.


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Upgrade Ender 3 with Diamond Hotend
As I want to print with multiple colors I plan to upgrade my Ender 3 with the diamond hotend.
So far I found all information I need, except what power supply I need for my RUMBA board.
Can I use the default Ender 3 power supply or do I need an additional power supply or wires?
Parts I am going to order:

1x Lite6 Heatsink
3x Diamond Universal mount
1x 12 V 40 W 6 mm x 20 mm Cartridge Heater Reprap For 3D Printer
1x Thermistor 100K 1 % NTC Temperature Sensor Line for 3D Printer
1x Fan 50x50x15 mm 12 V 125 mA
1x Diamond Hotend Insulator
1x Nema17 stepper motor 48 mm 1.8° 42BYGHW804 1.2 A 5.5 kg•cm
3x MK8/9 Dual Extruder Feed Device Part For 3D Printer 1.75 mm Filament
3x Bowden tube 1 m with fitting 4/2 mm (for 1.75 mm filament)
1x RUMBA 3D printer controller board
6x StepStick DRV8825 Stepper Motor Driver

Ender 3 is a 24v printer so you have to address the heater and fans at minimum.

The RUMBA boards run up to 36 V, so reusing the (24 V) power supply from your printer should be fine. As the 2 extra steppers do not take much extra power (note you are ordering only 1!), your supply should be sufficient. Note that a 12 V heater cartridge is not going to work on a 24 V board (you'll get a massive overshoot and probably over-temperature warnings and printer shutdowns).

Thanks! Your answer really helped me. I changed the 12 V heater cartridge to 24 V and added two extra stepper motors.

@Janik In total you need 3 stepper motors, you could salvage 1 from the current extruder,so that you need to order 2 not 3. But, I would also order 3 to have 3 the same.


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What can these horizontal lines be caused by?
I have changed stock Anet A8 board (Anet v1.5) to new SKR 1.4 with TMC2209. Then I found out these lines on the walls, I don't know how to determine it. Previously this wasn't so visible, but now it bothers pretty much.

Does this happen when printing with different filaments as well? Is the calibration cube dimensionally accurate? Please post settings report with M503 command for more info.

Please tag your printer, some printers have inherent problems.

Looks like an over/under extrusion. This can be fixed by:

decreasing/increasing your extrusion multiplier (flow)

lowering your print temperature

checking the diameter of your filament. Do you use the correct diameter?

I tried different values of Flow i.e. 90,95,100% - I think 95 works the best. I use the same printing temperature as you and the same filament diameter. Also i calibrated e-steps. I have been trying to solve this problem for several days and I have no idea.

authors: Марина Барановская


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PLA support material suddenly a problem on Ender 5
I have an Ender 5 that I meticulously calibrated with good success and was regularly getting great print quality with PLA. I stopped using it for a couple of months and when I resumed (without having changed anything), anything I print with support material is a real problem. The supports are really fused to where they touch the part and even tend to melt into the part. It ruins the print and isn't remotely removable without damage.
I've tried the other advice I've found here and from other sources: printing at cooler temps, increasing print cooling, checking bed leveling, etc. I was setting support in Cura, but switched to MeshMixer, which didn't improve the problem. Also, I had been using zig-zag pattern support, and lowered the density in settings, switched to tree supports...but nothing helps.
Before I resort to getting into granular settings to tweak how the supports are generated, am I missing something bigger, more general or more obvious? I find it strange that an idle printer started having such a specific problem.

New version of Cura? For settings see this answer, it might help you to create more distance between support and print object.

I honestly don't remember...but that's highly possible. I just tried these settings on a very small print and it's looking much better. If you want to post this as an answer, I'll accept.

As the commenter suggested (thanks, 0scar!), the culprit appears to have been a Cura update and a change to the support material settings.
In my case, the defaults for Z distance and even the X/Y distance for support material, in addition to the density, was creating very effective supports, but very tricky to remove. I should add that the model was a character sculpture, which I've since learned creates much more complex support scenarios versus the more uniform models I've been accustomed to printing.


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Why did my extruder motor stopped working?
Before it stopped working, the stepper motor worked very well and didn't show any problem. I experienced this after I fixed a filament problem. The filament got stuck soI retracted to pull the filament out of the heat nozzle. But when I finished this, the extruder didn't work anymore...
I restarted the system but it didn't work. All the motors work fine, even the extruder motor. The A4988 driver has the right voltage at 1.0 - 1.2 V. I have already replaced my RAMPS shield and AtMega board, but it still does not work! I changed the extruder motor to another axis port and it worked good. The voltage input is stable at 11.2 V
I can't figure out why the extruder motor is not working for the extruder port?

I have found an answer. So dumb♂♂. It need to heat up nozzle before use extrude or retract command

This means that you have #define PREVENT_COLD_EXTRUSION and something like #define EXTRUDE_MINTEMP 170 enabled in your configuration file (which is a good thing!).

Yes, I have this in my configuration file when I update new Marlin firmware but I forgot it

Glad you found the solution yourself and posted this! Happy printing!

To be honest, I've had a similar experience once :-)  But somehow, your question did not trigger my memory. Maybe because you don't mention temperatures; people assume that after the problem you tried to print, but instead you tried to extrude through the display or an attached print application over USB. If this had been added, people may have helped you sooner. If you [edit] the question to include that, you may receive upvotes to your question! :-)

Oh i see. Thanks for your suggestion. I will try to edit  my question more precise:))

When you pulled the filament out of the extruder you most likely induced a voltage back into the stepper driver which fried it.

But when i checked the motor, it still worked

Does the stepper driver what was attached to that motor still work?

Yes it stil work. I had changed it to work as x axis and it worked

You tried the motor on another stepper driver, but it still doesn't work? If not do you have a way of shorting the motor leads together? If so then do it and try turning the motor by hand. It should give much more resistance to turning when the leads are shorted than when they are not.

I tried to use another stepper driver from x axis on E0 but it not working. So i changed ramps

I already ordered a new driver and will try it tormorrow

I will try turning by hand and see it hard to turn or not.


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Surface artifacts when formation of object changes (Layer inconsistency)
When my Ender 3 prints a top or bottom layer, it leaves a line on the layer.

Slicer Cura
Linear Advance: 0.57
Retraction: 3 mm @ 35 mm/s
Max Speed: 100 mm/s
Ironing enabled
Minimum wall flow: 20 %
Temperatures: 205 °C hotend and 65 °C bed

My belts are tight enough as I push them they spring back up. I bought a support block for my Z lead screw to help with z banding (I also removed it to see if it will fix the issue but it didn't). I tried 50 mm/s, No Infill, swapped out to brand new 0.6 mm nozzle (the picture has 0.4 mm), Minimum wall-flow to 0 % but no improvement. It has to lead me to think its a mechanical issue but I am not sure where to start.

Try calibrating again it E steps and, if it doesn't help, try reducing the extrusion multiplier by 1-2%

@FarO I have calibrated e steps and flow rate from E3Ds guide. I tried 95% and 98% extrusion but it made it more more prominent. My current extrusion multiplier is 99.3%

However you see that the excessive extrusion happens only near the edges, where there is deceleration. Are you sure the linear advance calibration is correct?

In the calibration test, there is a bump but its the best compared to the others. I will do another test without LA and check the difference.

There is no difference.just the corners are more bumpy

Sigh... I am running into exactly the same issue. Whenever the layer changes to a new shape, there is a clear line. Have no idea how to get rid of it... Did you remove it eventually?

@YuxiangWang Yes, I have, I have posted the solution for my particular case.

I have found the issue. My extruder gear was deformed after 4 months of continuous use which made the extruder have a difficult time when a rapid change in extrusion happened. I swapped it out to a new stainless steel one and it has been working well so far.
EDIT:
These inconsistencies are mainly caused by the pressure in the nozzle not changing fast enough. So to solve this you should look at the extruder setup as that is where the pressure is being controlled. Get any gunk out of there and make sure the path is clear and make sure nothing is grinding and you have a good grip on the filament.
To reduce the change in pressure you should play with printing speed, hotend temperature, linear advance if applicable and you may tune extruder jerk and acceleration although not necessary.

Thank you! I did the same thing (I was already using aluminum extruder and switched to BMG) and it improved slightly. I found another person having similar issues and I think he was pointing to the same thing - sudden changes in extrusion totally caused it: https://www.reddit.com/r/3Dprinting/comments/ag1xq5/horizontal_lines_on_material_densitygeometry/

My next step will be switching to direct feed. Will update once I have it :)