Painting Q&A: Proper Oven Design
What kind of design is best for optimal efficiency of my painting line?
Q. How would I go about determining the proper oven design for optimal functionality for my paint line?
A. There are many variables that must be understood before beginning any selection process. First, always start with the parts and ask these questions: what are you coating, how big, how many and how will they be racked or carried through the heated stage of the process? When thinking about choosing the right oven, there are a few options depending on whether you choose radiant energy or convection heat. I will focus on convection heat and break down two methods for curing or force drying a paint film: cure oven or cure chamber. While the way heated air is created is very similar, the way that it is distributed through the oven or chamber shell is different. The main difference is the maximum heat that is created over the other. The cure chamber is typically for applications below 160°F and the cure oven can be used up to 400°F, even above if required.
Once you determine the size and weight of your parts, then you can determine the interior dimensions of the oven and the amount of energy it will take to fully heat up the product. Whether you are using a cure chamber or cure oven, you want to heat up your substrate at a rapid rate to reach full cure in the shortest amount of time. You do this not only with the convection heat you distribute, but by optimizing the number of air turns in the oven. You will typically use more air turns for a liquid coating than a powder coating because of the flashing that takes place during the curing of a liquid material. The last thing to keep in mind is how the air is distributed through the interior of the oven. When designing an oven, consider that the part and the part’s mass and configuration are part of the design consideration. The way the air moves through the chamber around the part will become a very influential factor in how consistent the temperature in that chamber becomes. If you keep these things in mind when designing and/or selecting an oven for any given application you will be able to optimize its functionality.
Steve Houston has been a business leader for more than 30 years. He is currently the chief marketing officer at Col-Met Engineered Finishing Solutions in Rockwall, Texas.
Originally published in the December 2015 issue.
Coating problems and solutions associated with particle size reduction...
Simply heating up the substrate does not cure the coating. There are many variables to consider when choosing the best cure oven for your application...
Specific questions about zinc phosphate and pretreatment are answered in one article...