Re: Stepper motors miss stepps

What kind of motors are you using? What sort of guide rails and bearings? How big is the mechanism? How heavy is the X axis?

If things are misaligned, the motors will struggle to move the mechanism. Make sure the mechanism can move easily without the belts in place. Next put the belts on tensioned loosely and make sure the mechanism still moves easily. Tighten up the bets and see if things start to bind. If you over tighten the belts you put a lot of lateral force on the bearings and guide rails. If they flex it will cause problems.

Pictures of the printer would help...