Hot Plate Welding of Plastics

Hot plate welding works by heating the two surfaces to be welded by pressing them against a hot plate with a non-stick PTFE surface.  Once the surfaces are hot enough, the hot-plate is removed and the surfaces are pushed together and allowed to cool.  Hot plate welding is popular because of low capital cost and wide process window.  The joint strength are very high and can approach parent material strengths.  However, cycle times are longer, 10-30 seconds, as compared to other techniques such as ultrasonic welding.

The PTFE coating can be used for plastics that can be heated below 250C; for temperatures greater than that one has to use either a plate without any coating or a heat the surface with a radiant non-contact heating.  Another approach would be to heat the surfaces with infra-red energy source.

Conventional hot plate welding is at temperatures in the range of 30 to 100C above the melting point of the thermoplastics.  In non-contact hot-plate welding, temperatures are 300-400C above melting point of the plastic.  Other factors include pressure/time/displacement during heating, joining pressure, and cooling time.

Applications include plastic barrels, air intake manifolds, fuel tank assembly and ports, and transport pallets.

For additional information or consulting services, please contact us.