Issue link: http://www.e-digitaleditions.com/i/901126
16 POWDER COATING, November 2017 does not have to reach the cure tem- perature. This allows for reduced dwell time in the IR oven and ensures that the tanks cool down much more quickly than the old process. • Previously unidentified problem solved: Moving tanks outside to cool — The faster cool down means that external fittings can be added to the tank while still on the production line. Previously, the tanks were moved out- side as they took so long to cool down. This involved extra handling of the tanks that is no longer required. Lessons learned It is clear that there have been many positive improvements that were not envisaged at the start of this real-world example. Most of us do not like sur- prises when we have just made major investment decisions, but extra cost sav- ings are always a welcome bonus. Overall, there are some takeaways our company has learned over the years that are worth sharing. The largest being that IR is not just a "like for like" powder coating oven replacement. IR is a sophis- ticated replacement option that offers a The first major decision was to move from an LPG (liquefied petroleum gas) batch powder coating convection oven to an inline continuous flow (0.75 to 1 meter per minute) natural gas catalytic IR system. This move alone would have a significant impact on production vol- ume. This simple change could have been achieved by installing a conven- tional, relatively low cost, convection oven. However, lack of available space was an issue. The move to gas catalytic IR not only solved the space problem, but it also al- lowed the oven to be split into 10 sepa- rately controlled zones. Each zone is PLC controlled, enabling stable, verti- cally programmable output heat distri- bution in each of the 10 zones. Just think about the infinite number of pro- files that can be created, saved in the memory of the PLC control, and re- called and activated within a few min- utes. Also, remember the lack of consis- tent cure on the collars and feet of the tanks? Problem solved! This is one of the features that sets gas catalytic IR apart — It has the ability to precisely control the application of IR heat to the point where it is needed most. Unintended consequences The main problems that were initially outlined by Metsa were resolved by in- stalling the natural gas catalytic IR sys- tem. Production was increased to meet demand, and a potential quality prob- lem was solved. In addition, several other benefits were achieved after the system had been installed and inte- grated into the complete manufactur- ing system at the customer's plant. • Problem solved: The move from LPG to natural gas reduced unit energy costs. Unintended consequence: The new IR system was so efficient that it resulted in an overall 75 percent drop in energy bills, even after taking the in- creased production into account. • Problem solved: The increased pro- duction output was achieved. Unin- tended consequence: It required no in- crease in labor overhead. • Previously unidentified problem solved: Cool down time — Because IR heats the coating, the entire tank Photo 1 Photo 2