Electrofusing of thermoplastic heating elements and elements made thereby

An electrical resistance heating element, comprising:

• a first polymeric component having a first surface thereon for receiving a resistance heating material:
• a resistance heating material disposed on said first surface, and
• a second polymeric component having a second surface for covering over said resistance heating material on said first surface;
• a substantial portion of said first and second surfaces being fused together by heat, pressure or both, whereby an unmelted portion of the polymer in said first and second polymeric components is stress relieved.

A method of manufacturing an electrical resistance heating element, comprising:

• a) providing first and second molded thermoplastic components containing a plurality of stress-raising features therein, and having first and second facing surfaces thereon, and a resistance heating material;
• b) sandwiching said resistance heating material between said first and second thermoplastic components to form a seam;
• and
• c) electrofusing a portion of said first and second surfaces of said first and second thermoplastic components so as to substantially eliminate said seam;
• and
• d) stress-relieving by heating a remaining unmelted portion of said first and second thermoplastic components which contain a portion of said plurality of stress-raising features.

A method of manufacturing an electrical resistance heating element, comprising:

• a) providing first and second mating polymeric components having first and second facing surfaces thereon respectively, and a resistance heating material disposed between said first and second facing surfaces;
• and
• b) joining said first and second polymeric components together at least along said first and second facing surfaces, whereby said resistance heating material is captured between said first and second mating polymeric components,
• i) wherein said first and second polymeric components comprising retention means including a plurality of male connectors located on said first polymeric component, and a plurality of female receiving recesses located on said second polymeric component for mating with the male connectors of the first polymeric component.

An electrical resistance heating element, comprising:

• a first polymeric component having a first surface thereon for receiving a resistance heating material;
• a second polymeric component having a second surface thereon;
• a resistance heating material disposed between said first and second surfaces;
• said first and second polymeric components comprising retention means including a plurality of male connectors located on said first polymeric component, and a plurality of female receiving recesses located on said second polymeric component for mating with the male connectors of the first polymeric component.