[Gashmore]

Working on an idea for a filament winding rig for making carbon fiber tubes and need the technique for calculating the torque required to drive the sled.

The sled runs back and forth a distance of 12' on a pair of square tubes. The sled weighs right at 8 lb and rides on ball bearing rollers. Tension on the filament is 10 lb. Friction loss is only a couple of ounces. Drive is 3/8"XL belt. PD of the 32 tooth drive pulley is 2". I would like to make one 12' pass every 20 seconds.

How do I calculate the right size stepper to handle the torque? I can figure the running torque but how do calculate the acceleration/deceleration torque?

[Askari]

Hi Ghashmore
Usually the most bigger part of running torque is belong acceleration/deceleration so if you use servo motor/drive you would able to read the average 10 last cycle torgue /current of your system.This method is so useful but you should 1-use servo system 2-at the first time you should use larger motor to find haw much is your RMS Torque(average torque).
For example if that parameter show 65 it means your requirement torque is about 65%*Motor rated Torque.
note:Its beter not chose system that cause upper 85-90% because after a while your system go older and the friction would increase so the current consumption get bigger.

By Stepper motor:
You can use these formula.
F=m*a
T=J*a
or look this page:
Servo Motors and Servo Drives | Technical Guide | Thailand | Omron IA

[harryn]

Hi, are you very concerned about thread placement accuracy ? I suspect that that narrow of belt will stretch a lot with that run rate.