Welding of plastic tubing

For a major Czech automotive manufacturer, we implemented a system of laser welding of plastic corrugated tubing and couplings for fluid distribution in cars. The task of OptiXs was to design a suitable method of welding the plastic tubing with a termination coupling and to supply the entire laser subsystem. In cooperation with the integrator, we were also involved in the design of the laser workstation.

We designed the welding system with sufficient variability so that even if the shape or size of the coupling was changed, there was no need to make major changes to the welding laser configuration.

At the beginning of our cooperation, we selected the Coherent Compact SE diode laser in combination with the Coherent PHFS0-BK radial laser head with a diameter of 94 mm as the most suitable for the task. Unlike scanning heads or conventional fixed-focus heads, this laser head allows the entire part to be welded in a single step without the need to rotate the part or move the laser head during the process. In addition, the PHFS0-BK / 90 mm welding head has sufficient internal space for easy handling of the parts to be welded as well as possible future changes in size and design. The entire assembly is completed with a 5 m optical fiber with a core diameter of 200 µm.

In a second step, we visited Coherent's application laboratory in Germany with the customer to verify the functionality of the designed welding assembly for several types of connectors and materials supplied by the customer in practical tests.

The welding assembly used:

Laser source Coherent Compact SE

Coherent Compact is a comprehensive range of diode lasers designed especially for plastic welding, soldering or soldering. The Compact SE model is a single-emitter fiber-coupled diode laser that provides output power up to 100 W @980 nm or 50 W @808 nm. The air-cooled design is easily integrated into production machines or laboratory environments without the need for additional cooling and auxiliary components. The design allows use as a stand-alone or can be easily integrated for mounting in a 19" rack.

Process Head Coherent Radial Welding Head PHFS0

The Coherent Radial Welding Head PHFS0 radial welding head allows simultaneous welding of a radially symmetrical component without rotating the part or optics. The dimensions and optical settings can be adjusted to the size and shape of the part to be welded up to a diameter of approx. 160 mm.

Conclusion

The designed welding assembly is suitable for welding defined parts with the required quality. During the inspection measurements and scans of the welded parts, it was found that due to the high quality of the weld joint, it will be possible to reduce the contact area of the coupling and the tubing and thus reduce the material cost of the part. The working time for welding a part varies in the range of 0.7~1.2 seconds/weld depending on the type of material used and the weld requirements.

More information About laser welding of plastics and polymers.

Products:

• Diode lasers
• Process heads and optical components