Plastic welding can be used in the creation of very complex parts.
Often plastic welding is used when replacing metal parts with injection moulding technology to allow the production of complex structures which otherwise would not be feasible.
Why choosing plastic welding?
If you have to create a tight container.
If you want to join two parts by a high mechanical resistance
If you want to cover with a functional part with a design part
If you want to insert a metal part into the plastic
You have several technologies to weld plastic. These have to be selected on the basis of the desired final result as every technology has its own features.
Techpol masters all state of the art processes to weld plastic parts:
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What is needed for welding?
A welding machine of the chosen technology! Then in relation to the part which has to be welded special welding masks need to be produced.
Design of the welding profile
Independently from the chosen welding type the design of welding profile is crucial for an efficient welding. Every technology has its own peculiarities which need to be evaluated accurately.
In ultrasonic welding - as an example - the energy conveyor (the edge which will be finally melted) shall always have a sharp profile. The reason for this is that melting should start from the smaller point.
Similarly the edge on the physical mould should never be done by milling but only by etching, as with milling you could have a radius on the edge itself.
In the fiction welding on the contrary the joint should be flat and have enough room to move during friction thus allowing it to melt and join with the counterpart.
The design of all welding joints foresees containment barriers.
The reason for this design is:
How do you ensure that the welding of the two parts was properly performed?
There are 4 typical tests for this purpose:
The last two tests are indicated in case you have a product with tightness requirements like for example a tank.
These tests can guarantee that the welding process was well executed and that there are no areas where the joint is just "squeezed" and not welded.
The problem of a squeezed joint must be carefully analysed
We have a squeezed joint when there is no melting but just a superficial sticking of the surfaces.
It is a very serious problem as it cannot be seen from the outside, so it must be verified with the previously listed test methods.