Method of lengthwise folding thermoplastic strip material and apparatus for achieving same

摘要

A flat stock strip of thermoplastic material is passed through a heating station in contact with the edges of longitudinally oriented heated knife blades to heat soften the stock strip along narrow longitudinal lines to define localized fold lines for the stock strip. The strip is fed sequentially through prebending device and a chilled forming die to set the reformed strip at the fold lines. Preferably the knife blades and any strip contact surfaces of the prebending device and the chilled forming die are TEFLON covered to eliminate scratching of the thermoplastic stock strip material during heating, reforming and cooling.