Re: OT: Are desktop 3-D printers ready for prime time?

John Doe wrote in news:r9rc68$k17$ snipped-for-privacy@dont-email.me:

If it is a toothed belt the drive side tension is all that matters. In a gantry/trolley transition set up, maybe two drive motors and the tensioned belt between them and the transitioning 'head' tied directly onto the belt at a fixed location.

Chain drives (bicycles) work with excess length because the top, drive side of the chain and sprocket combination does the "tractoring" over a toothed wheel (sprocket) zero forward backlash, but a lot can be had the other way.

dence.org:

it moves both way so both sides are "drive side" and there needs to be tens ion to keep the teeth from slipping

you don't need two motors just one motor and an idler pulley

Lasse Langwadt Christensen wrote in news: snipped-for-privacy@googlegroups.com:

Well, the two motor thing reduces backlash, but things like that get compensated for these days in the software.

I made an 800V amplifier for a piezo lathe head. It was a 20 -

20kHz amplifier and the piezo stack drove a lever that made a 2:1 gain for a 2mm total transition.

One could put a rod segment pellet in the lathe and it could turn it into a square peg with high surface quality.

Now they have lasers on lathe heads pre-conditioning surfaces as they are being cut by hard insert standard cutting methods.

getting the right length is easy, just cut the aproximate length needed and clamp both ends to the carriage,

--
  Jasen.