Slow Speed Lines

I have listened in on a number of the Barrier Deposition presentations at Roll-2-Roll Converting (AIMCAL) Web Handling Conferences over the years. One thing that struck me was the need for low-speed lines for coating barriers and conductive layers on film. The speeds mentioned were from 1 to 3 MPM. We are not good at making electric web handling lines for these slow speeds.

To run at low speed, we need high gear ratios, on the order of 300:1 or 400:1. These gears introduce a large friction component. I have had success at these speeds using mechanical clutches. Clutches require no speed reducers.

Another option would be using eddy-current drives which act like clutches.

If available, we could make good use of low-power motors with extremely low base RPM. We would require base speeds of 50 RPM or lower. Along with low RPM motors we require encoders capable of producing accurate speed readings at low RPM. Sine-Cosine encoders are available with the equivalent of 4M pulses per revolution.