Stepper physical connectins

[billsp]

I'm considering the purchase of a Sieg X3 and converting it to CNC. I was wondering the pros and cons between direct coupled stepper motors on the X, Y, & Z axis and offset steppers with a gear and belt?

thanks

[philbur]

Correctly designed direct drive works fine. Why complicate it.

Phil

Originally Posted by billsp I'm considering the purchase of a Sieg X3 and converting it to CNC. I was wondering the pros and cons between direct coupled stepper motors on the X, Y, & Z axis and offset steppers with a gear and belt? thanks

[mxtras]

Well, for starters - using a belt and pulleys allows you to effectively multiply the output (torque) potential from the motors and increase your potential accuracy. The cost of doing so is that you loose some speed.

Scott

[philbur]

You could just use a bigger stepper with direct drive. The normal issue with steppers is they are to slow for decent rapids so gearing down just makes it worse.

The critical issue with steppers is you need a bit extra in the size department in order to avoid the risk of lost steps.

A direct drive will give more than enough accuracy for the capabilities of an X3.

Just some thoughts from a novice.

Phil

Originally Posted by mxtras Well, for starters - using a belt and pulleys allows you to effectively multiply the output (torque) potential from the motors and increase your potential accuracy. The cost of doing so is that you loose some speed. Scott

[in2steam]

Originally Posted by mxtras Well, for starters - using a belt and pulleys allows you to effectively multiply the output (torque) potential from the motors and increase your potential accuracy. The cost of doing so is that you loose some speed. Scott

You loose speed in proportion to the amount of torque you gain not including loses for friction of the belt which can be enough to make a difference. I am direct coupling, this size machine and the average size stepper will be just fine. The only benefit I have seen in the belt drive is getting the stepper out of the way.

chris