Plastic welding techniques

Matrelec specializes in the manufacture of high-frequency, impulse and thermal welding machines.

Impulse

Impulse welding is a thermal welding process in which a thin blade is heated by short pulses of heat directly on the weld zones.

This process is similar to high-frequency welding, with welding and cooling cycles, as the blade rises and falls in temperature very quickly.

The process will be effective on thin materials when compared with HF welding, but will require a lot of power for large widths and thick products.

Finally, shaped tools are much more complex and costly than HF tools.

Hot air / hot iron

The main advantage of these machines is cost, compared with HF machines, without compromising production speed. However, they transfer heat from the outside to the inside of the material, making it difficult to weld thicker materials. Unlike HF, thermal welding overheats the outer surfaces and weakens the weld.

As with ultasonics, being able to work with a wheel makes it easier to handle a variety of shapes.

Compared with this technology, HF welding produces stronger, more uniform welds, thanks to a more controlled process. Hot air welding lacks precision, requiring greater control of the tool and constant visual inspection. What’s more, they don’t allow you to regulate the electrode temperature, unlike HF, leading to the risk of weld irregularities or drift.

This technique requires more experience, and is often more time-consuming than HF.

HF soldering makes it possible to redo a solder joint in the same place, guaranteeing air, water and bacteria tightness that is impossible with hot air or a hot iron.

Finally, unlike the HF process, these tools emit far more noxious gases, causing health risks, and also consume more energy, making them ultimately more expensive.

Ultrasonic

Ultrasonic welding of plastics relies on the use of high-frequency sound waves to generate local heat, inducing fusion of the surfaces to be welded. The advantage of this technology is that it can be used to weld or cut virtually all plastics, but will be more difficult to weld thicker materials or work with PVC.

Another important factor is the tooling, which is more complex and expensive than high-frequency welding, even if the possibility of working with a continuous cutting wheel makes it easier to process different shapes, to the detriment of weld quality.

Bonding

Another, even more economical method is to glue plastic materials together. HF welding saves a significant amount of time and creates much sturdier joints, avoiding the risk of welded seams breaking on the inflatable and promoting watertightness. However, gluing requires considerable preparation time and the use of adhesives containing solvents that are potentially harmful to health and the environment.