JOINING AND ASSEMBLY | INNOVATION
Laser welding is an important method for joining moulded parts in automotive and other applications. Peter Mapleston reports on this growth area and the latest equipment introductions in alternative technologies
Join together: options for welding moulded parts
From applications in hot and oily environments under the car hood, to clinical conditions in care facilities, laser welding is an increasingly attractive option for joining plastics parts together quickly, efficiently, and permanently. In this feature article, Injection World looks at what is out there now, using laser welding and other joining technologies. Laser welding began as a process that could only be used where at least one of the materials used for the parts being joined was translucent or optically clear (to allow the laser beam to pass through it to reach the join) – hence its popularity for headlamp assembly. But as it has matured, plastics producers have developed grades that, while transparent to laser light frequencies, are opaque to the human eye. Covestro, one of the leading global producers
of polycarbonate, points to the advantages of laser welding for various automobile components: not only headlights and taillights, where the technology is well established, but also items such as battery cases used in electric vehicles (EVs). Batteries used in EVs need to keep cool to function properly and retain their life span. One cooling process, known as fluid cooling, requires
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airtight seals to keep fluids contained and avoid spills. While several joining methods can be used to weld plastic battery packaging components, those like laser welding that do not require external agents (welding rods, for example) tend to be more cost-efficient. In the US, Covestro has worked with Leister
Technologies to develop process and material solutions for laser welding fluid-cooled battery modules used in various types of EVs, from passenger cars to buses and trucks. Battery cases injection moulded in an opaque flame-retardant Bayblend PC/ABS blend can be laser-welded shut. Flame-retardant plastics are preferred and often required for battery enclosures as they can help prevent or delay the spread of fires. “Using Bayblend FR3010, we developed effective
and reliable laser welding solutions for production- ready battery modules that can withstand battery abuse testing,” says Terry Davis, principal engineer, Covestro. Bayblend FR3010 has high impact strength, chemical and hydrolysis resistance, thermal stability, and a good balance of high distortion temperature under load and physical performance. For production of such modules, Leister offers
May 2020 | INJECTION WORLD 31
Main image: Lanxess has added three new products to its selection of laser- transparent Durethan PA and Pocan PBT materials
IMAGE: LANXESS
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