In reviewing some questions recently it became apparent that a key factor that keeps causing problems is a lack of stability or consistency in the process. My definition of the process in this case covers everything from the incoming materials onwards.
If the substrate is variable then it makes sense that the final product will be variable. Similarly throughout the whole process the target must be to try to make everything consistent and reproducible as much as possible.
An example of where improving the consistency before the vacuum deposition process might improve the product might be; Some substrates may be pre-treated by corona or flame to increase the surface energy and the lifetime of the treatment may be a variable depending on storage time and temperature after treatment. This can mean that the surface energy of the substrate can be as high as just after the treatment or back to the original level of the substrate before treatment. Ideally you want consistency with the surface energy the same every time. It is better to have the consistency even if the surface energy is not at the optimum value rather than have some rolls high and others low.
Within the vacuum deposition process too you need to be looking for the same stability. You want the wire feed to be as free and easy on every coil of wire and guide tube so that the friction is equal on every wire so that the feed will be consistent. A consistent wire feed helps towards a consistent molten pool which minimises spitting and keeps the coating quality high.
Once the major variables have been taken care of it is then these minor variables that take attention to detail that become the ones that are important to take care of.
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