Design Notes
Plastics locked down and laser welded Jonathan Magee • Managing Director • ACSYS Lasertechnik UK Ltd, Coventry, U.K.
Laser plastic welded automobile speedometer clock faceplate to housing.
Industrial lasers are used for diverse processing of engineering plastics across many markets. Some examples of the common processes are shown in figure 1, including laser marking, cutting, and welding. Well-recognized markets in the field of laser plastics welding include automotive (see figure 2), and medical devices. The rationale for laser plastic welding Laser-based welding has several advantages for plastics versus conventional contact methods. Laser welding is a non-contact process at the point of welding that generally takes place at the interface of overlapped parts, and thus the weld zone is encapsulated. This results in an aesthetically pleasing weld, which is sterile and does not contaminate the surface of the parts being welded. It seems counterintuitive that parts in contact can be welded together, om the top down, without disturbance to their outer surfaces. With conventional plastic welding techniques such as ultrasonic or hot stamping, contact with the outer surfaces of the parts to be welded together is inevitable. Non-contact laser plastic welding works on the principle of partial transmission, reflection, scattering, and absorption of laser light within the polymer chains being joined. By carefully selecting the plastics and laser’s optical properties, sufficient heat is generated at targeted locations to melt and fuse the materials.
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June 2021
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