Laser welding of plastics allows precise control of the welding process, avoiding the risk of fume and debris and improving the appearance of plastic components in the automotive, medical device and electronics markets. The Polyscan is a turnkey system for 2D welding of thermoplastic polymers — all the essential parts of the system are integrated into a compact and ergonomic enclosure allowing operation by a seated operator. Using any of the diode lasers or diode-pumped YAG lasers of the StarWeld series, three different wavelengths of laser source are provided by Rofin-Baasel (808 nm, 940 nm and 1064 nm) allowing solutions to be found in a wide range of applications.

Dynamic beam positioning allows the laser weld profile to be achieved without motion of the component to be welded, simplifying fixturing and clamping of the component. Laser welding is a comparatively new technology in the joining of thermoplastic polymers and offers a range of advantages including: superior optical quality of the weld, non-porous surface quality, minimal surface contamination (no debris), minimal thermal stress of the component (minimum heat input), high tear-resistance of the weld, and no vibration introduced into sensitive electronic assemblies.

In almost all cases the overlap joint configuration is used. The top layer of material is transparent to the laser beam and the bottom layer absorbs the laser energy to form an invisible weld bead at the interface of the two layers. A wide range of polymers including PP, ABS, PBT, PA and PC can be welded provided attention is paid to the absorption behaviour at the wavelengths of light used. In most cases, theoretical evaluation is not enough and practical trials are recommended.

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