ABSTRACT
For the last four decades, reflectors of car headlights, car signal lights and a few lighting elements have been metallized by aluminum evaporation in large batch coaters1,2. In the mid-seventies, subsequent plasma polymerization for corrosion protection of the aluminum deposit was integrated into the procedure3,4. Nowadays, the process sequence usually also includes plasma pretreatment and sometimes a plasma polymerized base coat for better adhesion and corrosion resistance of the aluminum coating in the same chamber. Some manufacturers also add an evaporated SiO top coat in order to avoid
fogging on car headlight reflectors. In contrast to this high degree of process integration, loading, evacuating and unloading of up to several hundred parts is still a very discontinuous (cycle time 30 to 45 minutes) and labour consuming process, interrupting materials flow in production. While the plastic reflector bodies come out from the moulds piece by piece or pair by pair each minute, lots of these parts are collected and stored near the aluminum batch coater before they are mounted manually onto the fixtures. These fixtures usually are tailored to specific parts, and if masking is also required then these become quite expensive. For mass production, hundreds of such fixtures, mostly of different shapes, have to be manufactured and stored. So, for the sake of continuous materials flow and cutting costs for equipment and labour, a coating system having short cycle time for small batches (close to the moulding machine) is highly desirable. Loading and operation should be simple, and the complexity of substrate holders should be low.
