Forum talk:Motors

If using an X,Y, system, why not use cogged wheels and teethed rails to give an accurate movement - it reduces the need for encoding and for belts that can stretch over time, loosing their base measurement. This would also allow for the use of cheep DC motors.

Oh, and give us the ability to create a quick mockup in lego technic easily enough.

Badspyro 04:28, January 27, 2010 (UTC)

If we want 300dpi, resolution, you'll probably need active control. I don't think a cog could position the write head within 0.003".

Well, the printhead is significantly bigger than just one nozzle, and to be honest, without getting a commercial nozzle at a cost of $90+ (without a datasheet) or ripping one out of an old BJ30 printer cartridge, you are never going to get 300 dpi, so we are most likely talking nearer, say, 100 dpi at best for something truly home fabricated.

If we are going down a more commercial parts list, then maybe use a servo to get higher accuracies between each cog-point? even then, I doubt it needs to be that exact as standard printers run off belts and cogs, which are even more inexact due to environmental differences and age/wear.

Badspyro 06:41, January 27, 2010 (UTC)

Stepper motors will give the best open loop control. If more precise control is needed then a closed loop control system will have to be introduced.