Powder on Heat-Sensitive Substrates
When it comes to powder coating heat-sensitive substrates, many factors must be considered to ensure the proper finish.
In the world of oven design, there’s engineering, there’s experience, and sometimes there is even a little art. When you add the challenge of working with heat-sensitive substrates, it becomes exponentially more difficult. When finishing a heat-sensitive substrate, all types of heat technologies must be considered. Powder coating for these applications requires an investment in process design to ensure a good outcome, and the answer is seldom based on an engineering chart. For the best outcome, the business as well as operational needs need to be considered.
For the purposes of this article, a heat-sensitive substrate is a part that by its composition or design is very reactive to applied heat. When working with a piece of steel sheet metal, there is not much an oven can do to harm the part. If finishing with powder coating, the powder would eventually burn once it is past its overbake protection, but the part itself will be fine. When a part is made from plastic, fiberboard or even wood, however, it is going to be a challenge to incorporate heating to the process. To powder coat a plastic part, for instance, the part would melt long before it would reach the 450°F required temperature to gel and cure most powders. Heat-sensitive issues can also apply to any part that restricts your powder line design such as part geometry. As well, some metal assemblies can contain a material that is heat sensitive, such as the foam core of a door.
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