Thermal Welding
There are a couple different types of thermal welding. These are hot plate welding and heat staking using a thermal press.
The process of hot plate welding uses a heated platen to melt the joining surfaces of the two halves of a thermoplastic part. The part halves are brought into contact with a precisely heated platen for a predetermined period. After the plastic interfaces have melted, the parts are brought together to form a molecular, permanent, and often hermetic bond. A properly designed joint welded under precise process control often equals or exceeds the strength of any other part area.
Advantages of hot plate welding include precise control of the melt temperature, excellent weld strength, ability to weld large, complex parts, and ease of attaining hermetic seals.
The simplified diagram below shows the stages in the hot plate welding process:
- Parts are loaded in their nests.
- The heated platen moves forward between the parts.
- The parts contact the heated platen. The plastic begins to melt.
- After the parts' joint interfaces are plasticized, the nests move back allowing the heated platen to retract.
- The parts are pressed together so that a molecular bond forms.
- The nests move apart and the finished assembly is unloaded.
Typical applications include automobile lighting, batteries, fuel tanks, and washer bottles.
Thermal press applications include heat staking, inserting, embossing, date coding and degating.
Dukane heat staking thermal presses can work with a variety of materials including most amorphous and semi-crystalline thermoplastics as well as liquid crystal polymers. Some difficult to weld plastics are well suited to the thermal process including lubricious materials such as PTFE. Soft thermoplastics such as PE and PP react favorably to thermal inserting along with brittle materials such as 50% mineral-filled PPO (Ryton) which flakes when subjected
Heat staking is used in the Automotive industry for door panels, map pockets, light-pipe staking, consoles, arm rests and switch clusters. Medical applications include blood-processing equipment, chemical pumps, fittings, flow meters, IV drug delivery and surgical instruments. Consumer Product applications include personal computers, portable telephones, laser printers, copy machines, video games, speakers and appliance components. Industrial applications include conveyor systems, gears, pulleys, couplings, and motor housings. Thermal presses are also used in Toy Manufacturing and the Sporting Goods industry.
For heat staking: http://www.dukcorp.com/us/PTH_ThermalPress.htm
For hot plate welders: http://www.dukcorp.com/us/PHO_HotPlate.htm