I'm building a CNC router with belt drive x & y axis, looking at using dual closed loop belts and stepper motors, one on each side to drive the gantry along the x axis (normally longer axis but will be the shorter one on this machine). I already have the linear slide rails for X (18" THK SR20), the Y (26" IKO WLW15) axis and two 170 in-oz steppers with encoders to drive the gantry along the X axis. The steppers will move the gantry by reduction belt drives to the main closed loop belts to allow the use of the smaller motors and changing drive ratios. Both steppers will be driven via gecko drives (the new G450) and slaved via Mach3. Currently looking at using GT2 5mm pitch PowerGrip 15mm wide belts and pulleys.
My question is:
Do I need a mechanical means to ensure synchronization of the dual belt drive so there is no skewing of the gantry due to lost/missed steps?
I see some designs are doing this. With the belts orientated for horizontal drive shafts mechanical synchronization is cheap and simple by using one long shaft connecting pulleys at the same end of both belts. But I've been considering vertical orientation of motor shafts and belts so debris falls away from the belt rather than getting caught in the teeth as is possible when mounted horizontally. By mounting vertically I'm hoping less debris will go between the belt and pulley thus reducing any precision errors in cutting (such as wave lines of the cut surface). Only way to mechanically sync for vertical is via another belt and set of pulleys, from what I can determine. This adds to cost of the project so I'm wondering if it's really necessary since my X axis is short. I haven't tested the encoders on the steppers but I'm assuming I may be able to use them to help measure any missed/lost steps.
Any guidance on this is appreciated.