Pulling tension monitoring during the melt impregnation of glass roving

Abstract The force required to pull a 2400 tex glass roving through a melt impregnation compounding process was studied. Pulling force was continuously measured by suspending the double belt puller in a sling held stationary by a force transducer. Process variables such as roving pulling speed, number of cylindrical pins, pin diameter, and melt temperature were studied using polymide 66 and polypropylene polymers. The results suggest that the tension build‐up in the roving is caused by a combination of two effects: viscous shear stresses in a thin polymer‐rich layer between the roving and the pin, as well as frictional forces caused by roving contact with the pin. A simple mathematical model is developed and used to adequately describe the experimental results.