AUTOMOTIVE MOULDINGS
With each new motor car model the number of plastic components is increasing. Similarly GAM is being more widely used as designers become accustomed to the advantages and greater freedom in design which the process offers.
Currently applications include :
* interior panels, glove boxes, dashboards, spare wheels
* internal and external door handles
* external trim, bumpers, side mirror casings
* under-the-bonnet engine components, sometimes made in glass-filled nylon. |
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| Recently an innovative application for the process has been oil conveying pipes including fixing brackets and other features, moulded as one component and replacing sub-assemblies of up to five or six parts. The gas core out forms the hollow tubular section in configurations which would be impossible for conventional extruded tube. |
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| CONSUMER DURABLES |
| This industry is starting to apply a wide range of applications in products such as refrigerators, air conditioners, washing machines, microwaves, and others. In refrigerators, applications include door handles, cabinet top covers, sub-frames, door and drawer front mouldings. GAM has solved problems in making thick section microwave and other oven handles in high temperature resistant materials such as PBT/PET with glass fibre. |
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| GAM CAN OFTEN BE RETROFITTED |
There any many examples of products and moulds being designed for conventional injection moulding when the application of GAM can solve problems such as eliminating sink marks and distortion. Gas injectors can often be fitted into the mould to achieve cost reductions and quality improvements. An example is shown of a CD case in which it was impossible to eliminate sink marks on the front visual face by conventional moulding.
| EXTERNAL GAS MOULDING - EGM |
EGM has been available for three or four years but is only now being applied effectively in large quantity production mouldings. A recent example includes a hand-held computer casing of a thickness of 1.5mm. Gas pressure is applied to the inner surface of the plastic in the mould in order to improve the opposite visual surface. At the same time the mouldings are flat, improving the joining of two halves of the computer case. This application could be applied to the ever-growing volume of mobile telephones in the future.
Estimates indicate that there are now over 2,500 GAM moulders worldwide, and current forecasts predict one in five machines sold in the future will be for use with GAM. Improvement in techniques and confidence in the process will accelerate its use, together with new versions of the process all using gas as a medium for applying pressure. Domestic appliance and mobile telephone industries are predicted to be the next major breakthrough for GAM.
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Courtesy :Terrence .C. Pearson & Rajesh .R. Wadhwa
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