PVC Window and Door Manufacturing

The manufacture of PVC and plastic profiles often involves ‘welding’ two PVC frame sections together.  This is accomplished by melting the two adjoining ends so that the melted plastic joins together and hardens in its welded state. The completed frames can be used to make windows, skylights, and some door profiles. Equipment used can be single point welders, 2 point welders, or 4 point welders.

Protection of Heat Platen During Corner Weld Process - PTFE glass tape or fabric is applied to weld plates to allow for heat to pass through the tape to accomplish a joint weld. The melted PVC will not adhere to the tape or fabric surface which allows for a clean weld. 

The equipment used for this process can vary in size and complexity. The simplest equipment is referred to as a single point welder. This equipment allows the operator to weld one window corner at a time. It is typically used for custom window profiles, or by small companies with relatively low volumes of window production. The next style of equipment is semi-automated and is referred to as a two-point welder.  As expected, this equipment allows the operator to weld two window corners at one time. The most popular style of equipment is used for high volume facilities – the equipment is referred to as a four-point welder. This equipment is usually more automated and allows for the sealing of a complete 4 corner window or door in one step.

The moving image shows a hot platen which is covered with PTFE-glass tape on both sides. The angle edge of the PVC profile becomes molten against the platen. The platen is then automatically removed and the two molten ends are pushed together and held in place while the molten plastic is held in place, forming the corner of a PVC window frame.

Key Considerations:

  • Tape or Fabric? - What style of material is being used to protect the welding plates? PTFE coated glass tape or fabric?
  • Die Cut - if volumes are sufficient, the customercan save cost and increase precision andconsistency with die cut tape profiles.
  • Fabric Sleeves - Can the customer benefitfrom die cut PTFE fabric sleeves?
  • Operating Temperature should not exceed the recommended temperature threshold of 250°C / 480°F for tape or 287°C /550°F for PTFE glass fabric.

Recommended Materials

For protection of heat platen during corner weld process, we recommend the following materials:

  • 100-5s, 100-6s, or 100-10s PTFE Coated Fiberglass tape with silicone adhesive
  • DXL 5s, 6s, or 10s PTFE Coated Fiberglass Tape with silicone adhesive – for better wear resistance
  • 100-5, 100-6, or 100-10 PTFE Coated Fiberglass Fabric which can also be die cut and fabricated into sleeves for quick change-overs
  • DXL 5, 6, or 10 PTFE Coated Fiberglass Fabric – for better wear resistance – which can also be die cut and fabricated into sleeves for quick change-overs.