Issue link: https://www.e-digitaleditions.com/i/954267
POWDER COATING, March 2018 25 • Ease of future expansion • Service costs (labor and parts) • Life expectancy of the oven and/or main components • Other considerations Boosting productivity Productivity can be improved in different ways, but typically it is achieved by speed- ing up the line or maintaining a more constant line speed. When you have products of different sizes and shapes, it is sometimes hard to cure them at the same rate. This is where IR can help. If you have a product that takes longer to cure, IR can be used to apply direct heat and bring the product's surface temperature up very quickly. IR can also melt and begin the flow of the pow- der faster than convection heat can. An example of a temperature chart is shown in Figure 1. Booster ovens are often used to improve existing systems. It may be as simple as installing a 1- to 3-minute booster oven in front of an existing convection oven. This boost will take the surface of a given part from ambient to anywhere between 300°F to 500°F, depending on what is desired to melt and flow the powder. This boost in temperature will then allow the existing convection oven to complete the cure of the powder. Bottom line, you can increase the line speed of your system or maintain your line speed with the heavier products by adding a booster oven. Choosing the best type of IR for your product can be complicated on your own, so the best thing is to contact sup- pliers who offer testing and installing of IR ovens. These types of suppliers will have a solid grasp of which oven or emitter will work with a particular product or powder coating. Testing is the best thing you can do to ensure that the right wavelength is used. Even slight changes in coating composition can change the emissivity of the coating and change the oven requirements. Testing will catch these changes. Test- ing can also determine if IR heat will af- fect the gloss or texture of the coating. It cannot be emphasized enough that testing, testing, and more testing should be done before you choose and install any type of IR. Saving money To justify the cost of adding an IR oven to your powder coating process, you have to ask some key questions. What is the revenue of the system (the money generated) where the oven is going? How much revenue per hour does this production line generate? How much revenue does the system generate per foot related to fpm? You need to know these things in order to base your cost savings on more than just capital cost. Here are a few things to consider in terms of cost savings: • Capital cost • Operating cost Figure 1