Plastics Application Fundamentals e-Book
Covers in detail about Polyethylene plastic, its properties and uses. Also covered is Welding plastics to gluing plastic pipes so you can trust them, as well as fiberglass construction and repair.
Plastic welding is one of the most innovative and different kinds of processes. It is specially designed for welding plastic materials, which are otherwise difficult to weld using conventional welding processes. For how to weld plastic parts, the films are fused and pressure is applied against them. The technique of plastic welding is diverse in nature, and has many variants with high number of applications for industrial use.
Various types of Plastic Welding
Hot gas welding
Hot gas welding is almost similar to gas welding, but it employs lower temperatures. A specially designed gun produces hot air with a feed for plastic, which makes the parts to melt and join them together. It is required for the plastic welding materials to possess similar chemistry. The technique is commonly used for manufacturing plumber fittings, big chemical tanks, and heat exchangers, etc.
In this process, the parts to be welded are placed together and the heated tips punch them, melt, and join them together. It is similar to the spot welding process; however, electric conduction is replaced with the puncher tips to perform the overall task.
Hot Plate welding
In this technique, a hot platen is used to melt the parts to be welded, as the two parts are held in the nests mounted on two anvils placed opposite to each other. The hot platen is allowed to move between the two parts. The two parts are pressed on the platen and kept as such until the plastic welding materials melt, and then the platen is removed, and parts are pressed together to create a permanent joint.
High frequency welding
High frequency electromagnetic waves are being used in this process, as certain plastics having chemical dipoles can be heated with these waves. This is one of the special variants of plastic welding and has very specific applications.
In this technique, high frequency sound waves are used in ultrasonic welding to melt the parts to be welded.
In Friction welding, also known as vibration welding, the parts are made to produce friction between them, and the effect of vibration between the clamping and the parts make the plastic welding material to melt, resulting in a weld.
The process involves holding a part stationary and the other one to spin against the stationary one with high velocity and pressure, and hence creating a weld.
In this process parts are pressurized while a laser beam is passing through. The parts that are to be welded are required to be translucent and opaque with a difference in their opacity.
This technique uses a solvent to dissolve the polymers temporarily, for, the polymer chains become free to move and can be made to entangle with other dissolved polymer.
Areas of application of Plastic Welding
Some of the areas of application are given below, however the technique may be used in various other fields also.
" Assembly welding for mass produced domestic appliances
" Fabrication welding of pipelines
" High speed seam welding of films and fabrics
" Precision welding of medical devices
See the next page for Plastic Welding Kits
We also have a chart about how to determine various plastic welding materials