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deformed shape

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Hi. I'm experimenting the deformation of shapes, specially circular ones. In the pic you see what I mean (curiosly, the inner circle got a deformation in a direction, the external one have it in another direction). I'm on a Prusa I3 mk8 (a Geetech...), which since a year so far didn't gave me such a problem. I'm with the latest Cura and nozzle .4 mm, printing PLA.IMG_20171009_110311.thumb.jpg.fae780495f334ed2ccaa606591d63849.jpg

IMG_20171009_110311.thumb.jpg.fae780495f334ed2ccaa606591d63849.jpg

Edited by Guest

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BUMP. The no reply problem is? That I'm not with a Ultimaker printer?

Well that looks like a mechanical problem not a gcode/cura problem. So is hard to help without knowing the machine as good as we know our UMs

Does that only happen with Cura? Maybe because slic3r prusa uses slower accel/jerk settings that doesn’t happen. Try to print it slower? Maybe someone of Prusa made a correct Cura profile mimicking the m slic3r prusa settings ?

Edited by Guest

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It could be a visual photo-effect, but there appear to be other deformations too: the shape being oval instead of round, different ring thicknesses...

I have no idea what a Prusa printer looks like, but I would guess this is caused by too much play in the mechanics? So, when changing direction, you get a sort of hysteresis effect?

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It could be a visual photo-effect, but there appear to be other deformations too: the shape being oval instead of round, different ring thicknesses...

I have no idea what a Prusa printer looks like, but I would guess this is caused by too much play in the mechanics? So, when changing direction, you get a sort of hysteresis effect?

Well that looks like a mechanical problem not a gcode/cura problem. So is hard to help without knowing the machine as good as we know our UMs

Does that only happen with Cura? Maybe because slic3r prusa uses slower accel/jerk settings that doesn’t happen. Try to print it slower? Maybe someone of Prusa made a correct Cura profile mimicking the m slic3r prusa settings ?

No hysteresis or visual effect. The problem is actually physical and it does present in any printing attempts.

Well, I'll try with Slic3r too, though I myself do not think it is a matter of slicer's brand. I used Cura so far, and until the current version this issue didn't showed up (though I wouldn't say that's an issue generated by Cura). Though, I might refer to some problem called backlash, such as described here:

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#circles

it seems to refer to an ultimaker test machine, but I wasn't able to "easily fix" my printer following this page, also 'cause I'm not sure of what pieces he's referring to). I lubricated the belts and the rotors, and thightened them in many ways, until the latest extent, but the problem stills efface.

This is a page from this very forum:

https://ultimaker.com/en/community/4732-cant-get-round-circles

BTW, sorry for my english: I'm not anglophone.

Edited by Guest

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Is this the top side (on your picture), or the bottom of the part? It's hard to see, but to me it looks like the printed object came (partially) loose from the buildplate and the softened material was just dragged around a bit in this area. The visible surface seems to be not flat and a bit "smeary"?

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Is this the top side (on your picture), or the bottom of the part? It's hard to see, but to me it looks like the printed object came (partially) loose from the buildplate and the softened material was just dragged around a bit in this area. The visible surface seems to be not flat and a bit "smeary"?

 

It is the prime layer: I didn't leaved the printer to continue to print, in order to avoid waste of time and material. All times when the prime layers started this way, the full object went deformed overall. The object was just removed from the build plate and placed upon a paper sheet, in order to be photographed, that's all. That's why it looks so deformed. Though, deformed or not, originally the deformation highlighted in the pic appeared when printing.

Edited by Guest

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the object indeed does not appear to be flat, inconsistent shadow so it could be adhesion too. I would not rule out any mechanical issues. The fact this behavior appears when you used a new version of Cura does not mean it is related. Or maybe something in Cura (accel/jerk) emphasizes a mechanical offset which was hidden before. Two events can manifest simultaneously without any relation. That it shows in any printing attempt may even vouch for this (mechanical) theory.

Also not familiar with Prusa, but is it ever necessary to lubricate belts?

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Perhaps I found the solution, after many experiments.

1) Tighten the belts (all of them), testing several tensions: I guess there's no universal recipe

2) Lubricate all mechanical parts, belts included

3) Always allow a brim plate (this seems to allow kinda break-in of the mechanisms). At least this seemed to work for me.

the object indeed does not appear to be flat, inconsistent shadow so it could be adhesion too. I would not rule out any mechanical issues. The fact this behavior appears when you used a new version of Cura does not mean it is related. Or maybe something in Cura (accel/jerk) emphasizes a mechanical offset which was hidden before. Two events can manifest simultaneously without any relation. That it shows in any printing attempt may even vouch for this (mechanical) theory.

Also not familiar with Prusa, but is it ever necessary to lubricate belts?

It doesn't appear to be flat simply 'cause I photographed it after I removed unkindly from the building plate... Though the evident problem was related to the jerks which I highlighted, and it faced in the print still firmly stuck on the building plate.

I also thought that the newer versions of Cura could be the culprit, but I was forced to abandon the idea: Cura was so far the most reliable slicer around: and I tried many of them. Perhaps with time it became more and more cluttered with many options which most "primitive" printers have no motivation to use for (and I wrote to them asking 'em to add my printer too: also 'cause it became one of the most used around, as for very economical ones: they answered that it was ME the one who had to ask Geetech to write to Cura's coders sendind 'em the specifics of their printer, in order to add 'em to the list... I did it, but no answer from Geetech crew...).

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