Plastic welding is basically the process of welding plastic parts together.The equipment used to accomplish this is known as plastic welding machine.The two pieces are heated and then pressed together and as a result cross linking of their molecules takes place.A filler material may or may not be used in between the two pieces which are to be joined.
There are many different types of Plastic Welding machines.These are:
Hot gas welding (or HGW) machine,hot plate welding (or HPW) machine,ultrasonic welding (or UW) Machine,spin welding (or SW) machine and vibration welding (or VW) machine HGW machines utilize the heat of a hot gas stream.The gas usually air is heated by the electric heating of the elements inside the welding gun.
The welding gas is directed towards the work pieces and the filler material (if used). The edges of the work pieces and the filler material are pressed together which causes fusion. Cross linking takes place when the materials cool down. As a result, a very strong joint is formed. This process requires a very high operational skill. HGW is applied in tanks, containers, tubes and repair works.
HPW Machines include a hot plate, which is placed between the pieces being worked upon. The hot plate is pressed to the work pieces and the heat of the hot plate causes the work pieces to soften. The plate is removed after sometime and work pieces are brought in contact and are then pressed with one another. As the materials cool down, cross linking of their molecules takes place.
Hot plates are usually made up of aluminium alloy. HPW Machines are used in the welding process of domestic electric devices like washing machines, dishwashers, etc and in the automotive components like fuel tanks, batteries, etc.
UW Machines is another type of Plastic Welding Machine.In this, the work pieces are pressed together and simultaneously high frequency acoustic vibration (ultrasonic) is applied onto them. The ultrasonic vibration is transmitted through a metal tool.The vibration causes friction between the work pieces- as a result of which local heating of the work pieces takes place.
This in turn causes the plastic to melt and coelesce in the mid-section. After some time when the materials cool down, cross linking of their molecules takes place. It has a wide range applications including medical equipments, electronics and computer components, etc. In a SW Machine, two cylindrical parts are brought in contact by friction pressure while one of them keeps on rotating.The friction between parts causes them to heat and soften.The rotation is stopped after sometime and the materials fuse together and cool down to form a joint. This welding machine is used to manufacture circular parts,floats,aerosol bottles,etc.In VW Machine,the two work pieces are vibrated at certain amplitude and frequency. This makes them rub with one another thus generating friction.
The friction in turn generates heat which causes the materials to weld and fuse together.As the materials begin to cool down, cross linking begins to take place causing a strong joint to form. VW Machines are used in the manufacture of domestic and automotive appliances.
Plastic Welding: How To Instructional Video by Techspan