Modeling of the tensioning system on a braiding machine carrier

Abstract Braiding is a manufacturing process for making tubular braided products like braided ropes, sutures and braided composite tubes. A yarn or tow tensioning system is required that consists of pulleys, two springs and a ratchet with the ratchet gear on the spool. The tension is nearly constant, varying within an acceptable range during braid formation and releasing a discrete amount of material from a spool when an upper limit on the tension is reached. A mathematical model of tension versus yarn displacement of a standard package tensioning system is presented. The response before ratchet release is a series of piecewise linear kinematic regions that include two separate spring preload regions, a single spring tensioning region, and a two spring tensioning region. During ratchet release the system is first modeled as kinematic, and later, more accurately as a single degree-of-freedom dynamic model. Ratchet reengagement that incorporated impact with an elastic yarn was required to improve model accuracy of response. Correlated experiment and simulation response validate the mathematical model, for use as a designer's tool.