UM 2013 - the next generation in accuracy?

[alaris2 1]

So we can print at about 0.1mm resolution. that's good enough right? but no, many of us want better, especially for repeatability (accuracy!=repeatability).

so I thought I'd ask the obvious question - just where is the backlash and inaccuracy in the current design? what prevents us printing at 10 microns repeatably? which parts are most to blame and should be upgraded /replaced

my starter for 10 is the belts. several of us have observed these stretching over time and continuously needing re-tightening (and how tight is tight anyway?). would re-inforced belts help perhaps?

what do others think (or can anyone categorically say exactly where the inaccuracies arise from?)

[noctis 0]

when you replace the belts with ballscrew drives, the long time accuracy will increase (in my opinion)

BUT: that causes in higher costs and lower printing speed.

A further option is the distance measurement with a Linear Position Sensor. But these are temperature sensitive, so ...

[destroyer2012 0]

I read somewhere that the belts we are using are not intended for precise back and forth motion, only precise motion in one direction. Switching to belts with a more curved (and maybe slightly bigger) tooth profile like reprap does would probably be one good step to take. The curved tooth profile ensures that the teeth cannot slide on the gear pulley.

THe next thing we would need is a good way to tension the belts, ideally with some kind of spring to literally apply tension to the belt (as opposed to the "stretch the belt till it's taut" method). This is the way all commercial 2d printers do it, and it allows the belt to be relieved of stress; that means no belt stretching over time.

[alaris2 1]

I read that too - something about GT vs GLX belts or something but I can't find the post now i want it.

what you're saying makes good sense - you don't happen to have any links to photos or other info about how commercial printers are doing this do you? none of the ones i've dismantled used belts so I have no comparison point.

The method of tensioning seems flawed at present - I quite liked what I saw in corexy which seems to make tensioning easier and uses less belts (= less problem?)

[fluxline 0]

A dual rail track and an arm using linear motors on a system about a meter in length is what I dream of. Perhaps just a bit a bit pricey and a little overkill for the rates plastic can be extruded but accuracy and speed improvements would be huge ... and quiet.