heatwelded

Heatwelded refers to joints or seams created by heat-welding, a bonding process that fuses thermoplastic surfaces by applying heat to reach a molten state and then pressing the parts together under pressure while they cool. This method produces continuous, often watertight, joints without the need for adhesives.

The process relies on localized heating at the interface and can be performed with several methods. Common approaches include hot plate welding, where two opposing surfaces are heated by a platen; hot gas or air welding, which directs warm air to the joint; spin welding for circular parts; vibration welding, which converts high-frequency oscillation into heat at the interface; ultrasonic welding, which uses high-frequency vibration to generate heat; and extrusion or mold welding, where molten material is extruded onto the joint as a filler.

Heat welding is typically used with thermoplastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), polycarbonate, and acrylic. Success depends on material compatibility, surface cleanliness, joint design (grooves or beads), and controlled temperature profiles to avoid burning or weakening the parts.

Applications include automotive interiors and exteriors, packaging films, roofing membranes, plastic tanks and piping, inflatable structures, and sheets or films used in construction and consumer products. Advantages include strong, watertight seams without adhesives, good chemical resistance, and suitability for automation. Limitations include the need for compatible materials, precise temperature control, potential thermal distortion, and equipment cost.

Safety considerations involve burns from hot equipment and fumes from heated plastics; proper ventilation, personal protective equipment, and training are recommended. See also heat sealing and plastic welding.