The weld area must be kept clean at all times. Surface preparation is necessary. Every particle that remains in between the weld and the parent material will affect the strength of the actual weld.
The best way to clean the weld area is to scrape off the first layer of the material surface.
All hot air-, extrusion-, or injection-welding joints should have a root bead on the opposite weld side to avoid a cracking area and to give more strength to the weld. It is necessary to weld down to the welding root.
If it is not possible to weld from both sides, the weld zone should be baffled out in an angle of 60� - 70� for all hot air and extrusion welders or 80� - 90� for injection welders. See the sketch below for the right bead angles.
Another important component is the weld size. As a sample and an easy to follow "rule of thumb," you can use the following:
Fabrication starts with material selection. After you know what kind of plastic is to be used and the dimensions are determined, you can determine what equipment you will need.
"Stick welders" require some skill. You must prepare the weld area and the welding rod. Maintaining consistent pressure can be difficult with these units because the touch of the person who makes the weld is what applies the pressure.
The distance of the welder抯 nozzle to the welding rod also has to be constant. The welding rod will melt faster than the parent material. For this reason a larger area of the parent material needs to be preheated.
Extrusion welders are much bigger and heavier than stick- and injection-welders. They provide a large weld bead. Many different sizes of extrusion welders can be found on the market today. Basically the welder position should be downward to use the weight of the machine to apply some of the required pressure.
Injection welders offer other advantages. They are light weight, fairly easy to use and the weld quality is typically high. You can weld different bead sizes by changing the aluminum tip to the proportions you need to weld.
To produce lots of long straight welds to join sheets together, a Sheet Butt Welding Machine is very efficient. This machine works like a hot plate welder.
For hot plate welding, the two parts to be welded must have the same shape. If a hot plate weld has to be done, e.g. in pipeline joints, the earlier mentioned parameters will apply for this kind of welding as well.
It does not matter what kind of welding equipment you use: temperature, pressure and time are always important. The equipment manufacturer and/or material supplier should have parameter charts for hot plate welding various materials.
Employee education is essential if you wish to achieve quality welds. Plastic welding looks
easy, but if you do not understand the importance of all the parameters, preparations and techniques, it can be difficult to achieve quality welds.
Therefore, we highly recommend spending some time and money on training. Many manufacturers and manufacturer抯 representatives offer courses.
Date: 2023-04-10 hits: 437 Return
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