[xrayxray]

Hi to all, after much research I'm still in two minds as to use reduction gearbox or reduction belt assembly.

Proposed machine- 3 m x 1.5 m combination router/plasma, rack and pinion on all axis, stepper motors of either 1200 oz or 1600 oz, dual racks either side on X axis.

I have a good price for 1600 motor and combine reduction gearbox of 7.5 to one....what are the pitfalls of this set-up as against a belt drive system....would backlash be a problem ?

Are there any other issues I should be aware of before I commence.

And yes I have searched for these answers but am still left in a little doubt through conflicting opinions, so a consensus of real application would be great appreciated.

Regards Xrayxray.

[awerby]

Gearboxes usually give you some amount of backlash, while belt drives typically don't. Also, if you gear down a stepper motor, you trade speed for torque, which isn't necessarily a good idea, since steppers lose torque as they go faster (or try to). With servo motors, this works better, since they generally want to go faster than your machine could handle if it was driven directly.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[ger21]

I think Mechmate builders have determined that belts offer much better performance.

Before purchasing motors, make sure you know what you're doing.
More often then not, when people here buy motors because they think they're getting a good deal, they end up replacing the motors, drives, or other components because the "good deal" motors were a poor match for their machine, and performed poorly. With steppers, bigger often times isn't better.

[xrayxray]

Thanks for your advice guys,

I guess the biggest problem I have is the incredible amount of resources dedicated to cnc..like this forum for instance.

I'm finding that there is an overwhelming amount of different opinions and information and filtering the good from the bad is a challenge.

I guess it's all part of the learning curve but when I want to invest my hard earned I want to make sure I am purchasing wisely.

Regards.