Printing problems with tolerances  

RE: Printing problems with tolerances

RE: Printing problems with tolerances

Your top layer seems overextruding. Lower your extrusion multiplier in prusaslicer. Maybe decrease step by step from 1 to 0.99 , 0.98 until the results meets your requirement.

RE: Printing problems with tolerances

I think this is a filament related issue, as i haven't noticed this with other materials.

Do you think this could be the cause of the problem I mentioned?

RE: Printing problems with tolerances

You can make individual profile for each filament in prusaslicer, because not all filament have same diameter. You need to calibrate each filament/color/spool. 

RE:

Do you use this method for calibration?

https://help.prusa3d.com/en/article/extrusion-multiplier-calibration_2257

I guess this operation has to be repeated for each new spool (and update the profile accordingly)

RE: Printing problems with tolerances

Yes, i use that method at first, but now if i see any issue like that, i just change the multiplier (increase/decrease the value) and see is there any sign of overextrude or under. I rarely use that method, except if i need to print something that need high precision, i use that method again.

RE:

I only noticed the overextrusion problem after taking the picture, without magnification i hadn't noticed it (usually i print with different materials, i tried the PolyMax in this case due to the mechanical features)... . Thank you very much for pointing me in the right direction (i'm still in the beginning and i have to learn a lot yet), tomorrow I will try to do some tests and see if it works out.

RE: Printing problems with tolerances

I have tried with some Prusament filaments and the problem is always present.

The strange thing is that doing the precise test indicated on the PRUSA website in theory the result would be that of an under-extrusion (on average I measure 0.41 / 42 on three sides and 0.44 / 45 on one side).

At this point I think that there may be a problem of another type. I haven't tried to correct the flux values yet, but if I have to do it for any filament type it's clear that something is not working well.

RE: Printing problems with tolerances

My thought about the differences size between every wall in precise test is because of bowden tube of the prusa mini. When the hotend move closer to the right, the filament/bowden tube will stressed out and bent, that will give more friction to the filament feed, so that will affect to the amount of filament being extruded to the nozzle. I think this will happened to all bowden tube 3d printer, i don't know if mk3s (direct drive) will show same results or not, i don't have mk3s so i can't say that my opinion is 100% true.

So you have to tweak the extrusion multipler to get the best results.

RE:

Also i've tried now to print https://www.prusaprinters.org/prints/1707-tolerance-coin and it seems to work fine (only 0.05 is fused but from 0.10mm everything works fine).

RE: Printing problems with tolerances

0.05 is almost impossible for me to achieve with prusa mini, because of every filament roll have different diameter tolerance, some layer would stuck/fused together. I think 0.1 is very good results. So if you can print that tolerance test coin and 0.1 is fine but the bag clip is failed, there must be something wrong with the bag clip settings in prusa slicer.

RE: Printing problems with tolerances

Posted by: @sandysasmita

So you have to tweak the extrusion multipler to get the best results.

Ok, i'll make some tests as you suggested above.

Thanks

RE: Printing problems with tolerances

Could you please add a gcode of a working bag clip (only if and when you have the time to do it)?

Anyway i'm trying to print bag clip with 0.98 just to see the difference.

RE: Printing problems with tolerances

Ok i will try to test the clip with 0.15 tolerance, i will update the results

RE: Printing problems with tolerances

Thank you!

RE: Printing problems with tolerances

I tried to print bag clip with 0.20 tolerance and extrusion multiplier to 0.97 and now it works perfectly (also there are now no visible sign of overextrusion on the top layer)... now i'm trying with 0.15 tolerance and 0.98.

So you are right... i need to tweak with extrusion multiplier in similar cases.

RE: Printing problems with tolerances

this object has large overhang that don't have something to stick on it. so i lower the speed only for the overhang parts. actually i try the original file that has 0.10 mm tolerance because you said the coin test was successful, so i try that one. here i attach the 3mf file and the gcode. the gcode was made for my eSUN PLA+ but i think it's ok to print using prusament PLA, you can change it to your filament settings in prusaslicer.

RE: Printing problems with tolerances

Thanks a lot.

Meanwhile I tried to print with tolerances 0.15 and 0.98 and this time the print was successful.
Tomorrow I'll try to print using your file. Anyway I think you were completely right ... better to rely on the visual method than on the precise one ... I was not considering the problem of over-extrusion, so thanks for your help.

I also noticed some interesting things in your file, I mean the changes you made. Gradually I am beginning to understand better how the printer works and the many settings i have to consider to get better results.

RE:

I tried your file (3mf) with my PolyMax filament and it failed at the value of 1 (extrusion multiplier). It works fine with 0.98 and perfectly with 0.97 (with no sign of over-extrusion on the top layer).

I haven't tried it with Prusament PLA (which guarantees greater accuracy of the filament diameter... but i had some problems with it few days ago) as i have to finish some prints today with PolyMax (i'll try tomorrow)

So if the problems persists with many filament (only when dimensional precision is required)... could it be a problem involving the extruder or the nozzle? Because i think i should have no problems at least with Prusament PLA (with diameter tolerance of +-0.02mm).

PS.
But... the coin test was succesfull (0.10) with PolyMax with the value of 1.0 in extrusion multiplier (with few signs of over-extrusion on the top layers)