Thread: stepper motors

Hi John,
First, although we try to answer questions you have given us very little to help you. A photo of your current setup would be valuable so we can see if your motors are Nema17, 23 or 34, how you are driving the axes, etc.

Without that I'll try to answer but I might be way of the mark so allow for that.

On 0.4 and 0.5mm pitch screws (effective pitch after calculating your pulley reduction) you are not going to run the machine too quick anyway. Perhaps reverse your pulleys so you double the pitch to 10 and 2 mm pitch and see if you get any better speed from it. Hopefully as simple as changing the pulleys around.

Printer steppers are only small and not a lot of torque so maybe new motors are the way to go. If you have done it on a tight budget then you probably have the best performance you are going to get. Lots of factors come into it and a few are - weight of the moving axis, pitch of the screw, friction of the linear rails, allignment of the rails and ballscrews, motor choice, power supply (higher voltage better performance) and driver board matched to the motors.

At a very rough guess without seeing your machine a starting point for you might be:
Price wise Nema 23 260oz/in motors and 24 volt 2.5 amp bipolar driver.
Performance wise Nema 23 378 oz/in motors and 48 volt Gecko540 bipolar driver.

If you go on the Gecko site there is plenty of good information about motor choices and driver boards.

There's an excellent stepper selection tutorial over at mycncuk.com forum.
It includes a spreadsheet for doing your own calculations.