A manufacturer of truck springs finishes suspension coil springs and torsion bars for the global automotive market using four coating lines. Customer demands forced the company to expand beyond traditional electrocoating and implement a powder coating system - a change that required the manufacturer to retrofit one of its four existing E-coat lines.
Conventional thinking dictated that two separate ovens would be required. However, "adding new curing ovens would negatively impact other parts of the production process and consume much-needed production space," said the plant manager.
An Infrared SolutionThrough the efforts and teamwork of the infrared (IR) equipment manufacturer and the Tennessee Valley Authority (TVA), the local utility, a unique solution was found. It had already been determined that electric infrared would be used to speed up the powder coating process, increase production and bring the unit cost down. But trying to squeeze ovens into the existing lines was not the answer due to the facility's space limitations.
A novel approach to put an IR booster oven inside the convection oven was then considered and implemented. Locating IR components inside the oven is possible with specially designed refractory boards and medium-wave quartz tube IR emitters, which are essentially impervious to the high-temperature atmosphere inside the convection oven. In addition, the refractory board reaches high enough temperatures that the board essentially becomes a secondary emitter and is basically self-cleaning.
The PaybackThe IR equipment design addressed all anticipated floor space problems and enabled the manufacturer to increase line speed and productivity. Now the company can quickly gel the powder just before the parts hit the highly turbulent area of the convection oven. The facility has also begun using IR in its E-coating line for dewatering.
Adding the IR booster system also changed the cure cycle substantially, since the direct heat was much faster than convection, and the radiant heat is now being recaptured. The company can turn down the convection oven set points and further save on energy consumption.