gr5

This is your cad software - when you export from cad to stl you can set how many line segments appear in a given arc. (stl format doesn't support arcs and cura doesn't either) Some cad programs do this in distance possibly "error" which might be in mm. Some do it in degrees/angle. But beware - if you set this too precise it will create too many points and your printer (assuming it has marlin in it - for example 99% of printers on the planet) then it can only plan out 16 points ahead of time and if those 16 points are all in the next 4mm it will slow down like crazy on corners and print ugly corners. So there is a happy medium between more points on a curve and not too many.

That pattern is classic underextrusion which can have many causes. Nozzle size .06mm? That sounds like the problem right there. Maybe you want 0.6mm? If you truly have a .06mm nozzle then you need to either make the layer height smaller or the print speed much slower. Or maybe you have a .6mm nozzle but put .06 in the slicer (this print would take days I suspect if you did that). Are you using cura or a different slicer? Which version of the slicer and what kind of printer?

@ahoeben - I just checked and there are these files - are these not printer configuration files? They sure seem to have javascript to control the parameters. This is from fdmprinter.def.json. Now I'm even more sure than before that you can do this kind of thing that the poster asked for. Sort of. "wall_line_count": { "label": "Wall Line Count", "description": "The number of walls. When calculated by the wall thickness, this value is rounded to a whole number.", "default_value": 2, "minimum_value": "0", "minimum_value_warning": "1", "maximum_value_warning": "10", "type": "int", "value": "1 if magic_spiralize else max(1, round((wall_thickness - wall_line_width_0) / wall_line_width_x) + 1) if wall_thickness != 0 else 0", "limit_to_extruder": "wall_extruder_nr", "settable_per_mesh": true }

You got the wrong impression then. Well then how come when I set the shell width to various values there is clearly some kind of formula for auto calculating the wall line count? Or is wall line count not part of profiles? It looks like at a minimum one can do division (divide shell width by line width to get wall line count perhaps) in a profile. I thought I saw other examples of math happening but maybe none of those are part of the profile and they are all hard coded by cura?

You have to upgrade to the "plus" firmware. There are twice as many steps/mm because of the 2:1 gear ratio. Plus I think it might turn the other way? Also you have to do a factory reset to move the steps/mm setting from default firmware setting into the eeprom. Without a factory reset it tries to use all your previous values (including steps/mm on z axis). Also it's possible you connected a fan cable to the Z 8/16 microsteps jumper. You want the jumper not connected - it's right in the middle of the board. Some people connect one of the fan cables to that by accident. If you look carefully it says something about 8 versus 16 microsteps for Z axis. And the fan cable is close enough to a short to make the stepper switch to 16 microsteps and hence move half as far.

It's not exactly caused by the part shrinking. It's because as it extrudes, PLA sticks to itself like snot. Like a liquid rubber band. And it is also shrinking rapidly while still liquid so it is pulling inward. and when you go around any corner it pulls inward. It's a little worse on corners. It gets better as you get farther from the heated bed. It seems to help if you have double pass walls (e.g. line width .4mm and shell width .8mm) as the inner wall helps hold the outer wall in place.

I'm wondering if you purposely level the second nozzle "wrong" you can get it to squish the pva into the pla harder enough so that this works nicely. On the other hand the second nozzle would have a tendency to scrape/scratch the pla on the layer below.

You want the capacitive plate as close to the glass as possible to get more accuracy. The aluminum plate on the UM2 in my opinion is much too far. I'm going to just wildly guess that the accuracy is proportional to the square of the distance so 2X farther away will be 4X less accurate (it's probably linear not square). Also the larger the plate the better.

Well just glancing at UM recommendations they say 220C for um2 nozzle and 100C for bed temp. The 100C bed temp implies the softening temp is somewhere around 90C or much hotter. Therefore I would print it similar to ABS and use very little fan. Maybe 30% on UM2. Maybe a bit less as long as it spins (20%?). Looking at the photo I don't have any obvious ideas. It looks like *maybe* you are printing too cold or *maybe* not enough fan or *maybe* you are underextruding. I really don't know. I just don't know this material well. I would consider printing at one third the speed you are printing at just to see if that helps - that would certainly help underextrusion issues - just play with all 3 of these settings while printing from inside the TUNE menu and keep good notes because a month later you will forget half of what you learned.

> - Should I contact the Singaporean reseller to ask for replacement of the broken feeder and will it be charged? Absolutely. yes. Ask them to send you just the spare part. It may take a week or two. > - or should I try to create and print a support hanger with screw hole to attach the broken feeder? You should do that also. Do both. Don't modify the printer without the reseller's permission but you should be able to get permission. They usually would rather just send you one spare part than have to receive and ship another entire printer *and* the fix it themselves.

First of all you need to learn about layer view in cura. This would have shown you the problem before you started printing. When viewing your model in cura there are 3 modes - find layer view. Nextly the problem is in your cad model. If you switch to xray view you can usually see the problem - if you see anything in red then that is the problem. Most likely you have overlapping volumes of extra walls somewhere in your cad model. Was this sketchup? Sketchup isn't the best for making real things but I used it for a year so it can be done. Here is a guide to making manifold parts with sketchup: https://i.materialise.com/blog/3d-printing-with-sketchup/

By changing the way you print you put more stress on the Y axis and it is slipping. But the root problem is that one of the pulleys is loose. There are 5 or 6 pulleys on the Y axis - you need to tighten the little set screw in each one. Tighten the hell out of that little screw - so much that the tool is twisting almost. usually the most important one - the problem one - is the hardest to get to - one of the two pulleys on the short belt: either the one on the stepper motor or the one just above. You might be able to tighten the one on the motor without removing the left rear cover but if you do have to remove the cover it's only one or 2 screws (depending how old your printer is). More info about all this here: http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide

What? No microstepping? If you take away the 16X microstepping and want the same positional accuracy you would have to add a 16X gearbox. Also I'm not sure if the steppers can run 16X faster - they would need to handle 40,000 steps per second to hit 300mm/sec.

3dsolex.com has ruby cores.

yep. If you followed that chart in the link I posted above you can see that tinkerCad is recommended if you want something free and simple and want to do precise parts versus sculpting.

There are many reasons this can happen. The model can be too big. The model can have walls that are too thin (thinner than nozzle). The model can have holes in the walls (so cura doesn't know inside from outside of any point in the model). A picture of your model would really help.

It's a cad issue. You could fix this with meshlab. Or maybe there is a way in freecad to merge all overlapping objects into one object? I know DSM. In DSM I select everything and there is a button to merge.

Go to menu item "preferences" then "configure cura" then uncheck "ensure models are kept apart".

I answered those questions once years ago. Now I just choose the last option which is something like "I don't want to answer this" because I don't want to send duplicate info. But you can just always choose that (I have to do this every time I upgrade cura).

It's called underextrusion and happens if you print too cold (too viscous) or too fast (in volume not print head speed). It could be your printer is faulty or it could be you are above the expected max speed for your printer. What kind of printer is it?

I love DSM but it's not for everyone. Please go through this flowchart as I think it's pretty damn good: https://www.gliffy.com/go/publish/5271448

You should be able to get a 0.8mm chinese nozzle for about $5 on ebay. I believe any e3dv6 style nozzle will work but I'm not certain as I don't have a prusa. I think telling the printer you have a 0.8 is fine. Worst case it will underextrude and give you mabye .6mm walls. You can measure with micrometer after it is done. If you print hotter (e.g. 240C should be okay) and slower the printer can definitely keep up. I would just experiment as it's printing within the TUNE menu and play with temperature and speed from there. Actually this is good to know in general so I would slice a 30mm cube with no shell (set shell=0) and 100% infill, then once it is up to speed I would play with temperature and print speed to see where you get gaps in the infill and take good notes. Test temperatures from 190C to 240C in 20C increments and graph it for future knowledge (speed versus temp). I did this very thing with my UM2 ages ago. The results depend a lot on temp sensor and even more on feeder power - how hard the feeder can push.

Strange. Yes, go cooler on the bed. Print walls 2 layers thick (e.g. shell 0.8mm and line width .4mm) so that the inner wall helps hold the outer wall as it is being laid down. Fan is important - are you using 100% fan by the 4th layer? You can go to 40C on the bed I think. Just beware the part may lift off the bed if you go too cold. You could even switch to blue tape washed with isopropyl alcohol (never use blue tape without washing with alcohol). With blue tape you can turn off the bed completely. You can also drop the bed temp by 10C as soon as the first layer is done. The heat has 3 purposes - if it's above the glass temp of 55C then the PLA is more flexible so that warping forces from above don't pull the part off the bed. But you are below that so you aren't using that purpose. The second purpose is allow the filament to flow better into micro cracks in the glass or at least flow onto the glass well. The temperature needed for this is around 35 to 45C. Cooler than 35C and parts barely stick at all. The third thing is to not change the temperature much after you start because the plastic shrinks much more than the glass so you increase stresses and the part might pop off. But 10C drop in temperature should be safe. So you could start the print at 45C bed temp and then lower to 35C as soon as the first layer is done.

Get rid of arduino please. UM4 needs 32 bit motion planner. Keep the dual computers though -that part I hope continues into the UM4 design.

If the numbers don't agree then your printer might be underextruding.