Types of Plastic Welding Techniques Used Today
Plastic welding is actually welding for the semi-finished plastic materials and is also described as a process to unite softened material surfaces with the use of heat, except for solvent welding. Welding thermoplastics can be accomplished in 3 different stages and these are surface preparation, application of pressure and heat and lastly, cooling.
There are various welding methods that have been introduced and developed for joining semi finished plastic materials. Depending on the mechanism of heat generation at welding interface, welding methods for thermoplastics may be deemed as internal and external heating methods. In reality, there are countless of welding techniques that are being used for semi-plastic products which include the following:
Hot gas welding – this is also called as hot air welding which is a kind of plastic welding technique that is using heat. It is using special heat gun that’s called as hot air welder which produces jet of hot air that is softening both end parts that have to be joined and plastic filler rod.
In fabricating and manufacturing smaller items such as plumbing fittings, heat exchangers, chemical tanks and water tanks, hot air/gas welding is used.
Welding rod – plastic welding rod is also called as thermoplastic welding rod which is a rod with a triangular or circular cross section that is used for binding 2 pieces of plastic together. They are available in different colors to be able to match the base color of material.
Air bubbles or voids in the rod will come up if the plastic welding rod has high porosity. The welding quality greatly diminished if this happens. For this reason, it is highly recommended to use plastic welding rods that have zero porosity or known to be voidless.
Heat sealing – for this process, it seals one thermoplastic to the other such as thermoplastic using pressure and heat. Direct contact method for heat sealing with the use of constantly heated sealing bar or die in order to apply h eat to a specific path or contact area to either seal or weld the thermoplastic together.
Believe it or not, there are many different functions for heat sealing such as thermally activated adhesives as well as film, foil sealing or heat seal connectors. A common application for heat sealing process is joining PCBs to LCDs in different consumer electronics and sometimes, in telecommunications and medical devices. Heat sealing of products using thermal adhesives is to hold clear display screens to the consumer electronic products and also, for other sealed thermo plastic devices or assemblies where ultrasonic or heat staking welding isn’t an option because of part design requirements or any other assembly consideration.