Don’t Tune Your 3D Printer To Middle ‘C’ After All

3D printer belt tension seems like a simple thing to deal with — you set the tension and then check it's good now and then. If it gets really loose, then the teeth can slip and you’ll get some shifts in the print, ruining it, but its an easy fix. But, we hear you ask, how do you determine what the correct tension is? Well, here's [Lost in Tech] with a video showing some measurement techniques and analysis of a typical 3D printer, (video, embedded below) using nothing more special than a set of luggage scales. A simple theory suggested was that a tighter belt tension would result in increased radial load on the stepper motor bearings, which in turn, due to friction, would result in an increase in temperature of the motor. After setting a few tension values on one of the belts, it was noted that tension values at the upper end of the range, resulted in a measured increased in temperature of two degrees celcius, and a large increase in noise. This can't be good for the motor.

Looking at the specification sheet of a typical NEMA17 stepper motor showed a value for the maximum working radial force of 28N, so it was simply suggested that tension values resulting in a load beyond that, would offer nothing other than reduced motor lifetime. Print quality did not noticeably change, even with really loose settings, until the belt was loose enough for axis movements to significantly lag the motor input.

As [Lost in Tech] suggests, maybe that old adage of tuning belt tension to a ‘middle C’ might actually be far too tight and cause more problems for you than problems it solves?

Obviously we’ve covered many 3D printer hacks over the years, like this huge belt driven printer, just beware that even something as simple as a belt clamp can go wrong with bad design, and finally, whilst we’re thinking about belt drives, here's a cool belt drive extruder to ponder.

Thanks to [Zane] for the tip!