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Design Course
Designing of Plastic Products for Injection Moulding
Manufacturing Methods and Technologies
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Metallization
Metallizing is a technique of depositing or coating the plastic parts with metals. Metal coatings are applied for decoration as well as for functional reasons. Metal coated plastic parts are economical lightweight alternatives for various automotive applications like grills. Functional coating provides electromagnetic shielding, circuit paths or reflective surfaces for lightening applications.
The processes for applying metallic coating on plastics are
- Electroplating – In this process the plastic part first undergoes an electroless chemical process to deposit a conductive metallic layer. In electroless process part is immersed in a series of aqueous baths to clean, etch and activate part surface. Then a metallic film layer such as copper is chemically deposited on the part through conventional electroplating process.
- Vacuum metallization – In this process a very thin film of about 1.5 microns is deposited on to plastic part in a vacuum chamber. The first stage of the process involves the application of a base coat to the parts to improve metal adhesion to the surface. Then the parts are moved on to a rack which rotates in the vacuum chamber for uniform deposition of the metal over the surface. Deposition take place by vaporizing the metal using tungsten filaments or electron beams. The final step involves the application of a clear top coat to protect thin metal film from abrasion.
