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:
containment of melded material, which during welding can be generated in the form of burrs.
An improved welding result as melted material meets the containment chamber and joints with the walls in this area.
How do you ensure that the welding of the two parts was properly performed?
There are 4 typical tests for this purpose:
Sectioning of the joint and visual test
Traction test on the joint
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.