Printer Resolution

[AClark1983]

The Solidoodle has a small gear head for the belt drive. If the error in the stepper motor is what the main error is then making that gear smaller would cause there to be less error. The assembly would probably need a larger stepper motor after losing some mechanical advantage. I am going to check the Taz 4 tomorrow and see what the motors and steps per mm are rated to. If they are close to 88 steps per mm like the Solidoodle then the MFG must just rate the machines off the error in the stepper motors.

[truly_bent]

AClark;

There is a little bit more to changing drive pulley tooth counts than just swapping in a new one. Unless you can reconfigure your software parameters for the axes drives (assuming you plan to do both X and Y axes), your dimensioning will be out of whack - by a bunch. You have to be able to let the stepper drives, or the software commanding the stepper drives, know what the new gearing ratios are. You might want to tinker with the ramp rates while you're in there as well (ignore this part of the message if you already know this).

Personally, i don't think you're going to gain much by dropping the tooth count on an already small pulley. I mean, how small can you go - another 20% maybe? If you were to add step down gearing you'd be onto something, but that would require a major revision of the drive mechanism and it would likely end up being a much slower system. Maybe that's an acceptable tradeoff.

[AClark1983]

Okay, so I checked the Taz4 this morning. The printer is set to 100.5 steps per mm in the X and Y axis. The stepper motors are 200 steps per turn making motion 1.99 mm per stepper motor turn. At an error of 5% the machine could be commanded +/- .0995 mm. .0995 mm on the Taz4 is a little better than +/- .1136 mm on the Solidoodle. Maybe we have something now. Anybody out there have a machine that is rated to .05 mm or .2 mm?

[Marm]

The simple solution is a reduction gear. Turn those same 2mm steps into .25mm steps. or whatever. But again, you'll have to adjust the software to compensate.

[truly_bent]

AClark;

Bukobot 8 says their system is good for 0.05mm ($1300).
Ultimaker 2 says theirs is good to 0.02mm ($2500).
I guess you get what you pay for...

[richardphat]

AClark;

Bukobot 8 says their system is good for 0.05mm ($1300).
Ultimaker 2 says theirs is good to 0.02mm ($2500).
I guess you get what you pay for...

Most printer with 1.8 step can achieve 0.02mm
Both bukobot and ultimaker can probably go lower than 20microns since they used threaded rods.

Just typical marketing to avoid backfire....

[AClark1983]

Does anybody have experience with the Bokubot or Ultimaker that can testify to the resolution? By my math the Bokubot has 111.98 steps per mm so with 5% error that is right at +/- .089 mm. I would believe a system that was all threaded rods with 200 steps per mm would be +/- .05 mm. If the system is using higher quality stepper motors that error might be lower.