Cutting and sealing process for thermoplastic materials

A process for cutting multiple plies of oriented thermoplastic material having thickened sections and simultaneously sealing severed margins thereof comprising the steps of:

• (a) clamping the material adjacent the area thereof to be cut and sealed;
• (b) selecting a cutting and sealing element with an elongated cross-section having a height to width ratio from about 5:1 to 2:1, capable of being heated and for a length at least as long as the section to be cut and sealed;
• (c) heating said element to a temperature sufficient to cut and seal said material;
• (d) biasing the travel of said element so that an engaging edge thereof passes through the thickened section for a distance no less than that through the rest of said material and without the entire element passing beyond the last ply to be engaged by the element but sufficient to sever all such plies;
• and
• (e) permitting the severed plies of material to retract a given distance and form a sealed edge.