Plastics Welding Training - · PDF fileTWI was invited to review the internal welding ... Mechanical testing Tensile Flexural ... Plastics Welding Training
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Plastics reduced the weight of the average passenger car built in 1988 by 66 kg Saves millions of gallons of petrol each year Will save the energy equivalent of 21 million barrels of oil over
the average lifetime of those cars
By the 1993 model year, over 114 kg of plastics were used in the average vehicle
By 2020 plastic will account for 18% of average vehicle weight
Global trends are pushing automakers to reinvent their product and manufacturing processes
Replacement of engine components such as the engine manifold requires advanced engineering thermoplastic materials, which need to be moulded into a complex 3D structure
Such structures will often be designed and moulded in two halves
Advanced new-materials with complex designs demand suitable joining solutions
Weld quality of plastics is very much dependent on both the material and the joint design for the specific welding process
Companies have their own internal specifications for Welding of Plastic Parts which dictates both design and welding/joining aspects of plastic components
Verification of weld quality has been a challenging task:
CT images of a welded vapour separator: a) complete component with the six critical locations (1-6) marked b) a slice through the part exposing the weld interface and weld-flash
“Design Rules” for vibration welding dictate critical dimensions which should be adhered to if a good weld is to be expected
In most investigations the unwelded parts of the component are not available to measure and compare against the “Design Rules”
One major advantage of CT is that the joint design dimensions of the welded part under investigation can be measured on the CT images using software which allows live measurement analysis of the weld-lines
Scope Under the direction of WEE/3 is responsible for the preparation of
British Standards specifically in the welding of thermoplastics materials using the following processes: laser, linear vibration, spin, hot plate, infrared, hot ’convection’ gas and ultrasonic welding. The group also provides the UK input into CEN/TC249/WG16
Who is currently involved
BSI Secretary - PRI/-1
TWI Ltd
Jaguar Cars
Ford Motor Company
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Committee: WEE/3 Welding of thermoplastic moulded components
Day – 1 Introduction to plastics & welding principles Heated tool, infrared & hot gas convection welding Vibration welding Demonstrations of heated tool & vibration welding Tour of the facilities
Day – 2 Ultrasonic welding Laser welding Spin welding Ultrasonic & hot air stacking Vibration welding Demonstrations of ultrasonic & laser
welding
Day – 3 Mechanical & non-destructive testing
of plastics welds Design Rules Other welding techniques for plastics Adhesive bonding Multiple-choice examination Feedback & discussion
CT has proved to be an impressive tool which provides a non-destructive test of welded parts
Enables direct comparison against “Design Rule”
X-ray, CT highlighted:
Non-uniform weld flash around the perimeter of the weld
The weld step-H (tongue and groove), weld-flash created and the weld-gauge were inconsistent and did not pass the criteria set by automotive company’s Design Rules