Infrared Ramping Solves Powder Curing Quality Problem
One of two Kawasaki Consumer Products Division plants in the United States, the Lincoln plant produces motorcycles, jet skis, all-terrain vehicles (ATVs), mules and industrial robots. The 1 million ft2 of facilities at Lincoln include office, manufacturing and warehousing space. Manufacturing operations at the plant include fabrication, molding, finishing and assembly. Its finishing operation for wheels for ATVs and mules was encountering quality problems in powder paint curing.
The plant's output of about 6,000 wheels daily for Kawasaki and competitive products is finished in a range of colors including white, silver, pearl gray and black. Curing, which was performed with a convection oven system, was resulting in "bleed-through - a yellowing of the finish coat - from the gray electrocoat beneath it," according to Dave Reinke, production engineer at Kawasaki.
The company determined that a lower oven temperature combined with a longer dwell time would solve the problem, but accomplishing this with convection heat would have required expanding the oven cavity size and adding burner capacity. "We didn't explore that possibility very far because of space limitations," Reinke said.
The company decided that an infrared "ramping" system, which would quickly raise the parts from ambient temperature to final curing temperature, would be a key to improved quality.
After deciding on an infrared system, Kawasaki called on Catalytic Infrared Systems, Independence, KS. "Some people we talked with who had catalytic infrared systems told us that if they had it to do over, they would use Catalytic Industrial Systems," Reinke said. After consulting with Catalytic personnel and talking with some of the company's references, Reinke selected Catalytic.
With catalytic infrared, natural gas is brought into contact with oxygen in the air in the presence of a catalyst. The resulting reaction - which is flameless - generates long-wave infrared radiation, which is readily absorbed by most materials. A few minutes of electrical ignition brings the system to starting temperature, after which the reaction is self-sustaining. The process is fuel efficient and offers energy savings.
"The oven's convection zone then is used to hold the parts' temperature and allow the heat to 'soak' through the entire product," Reinke explained. The wheels spend a total of 30 min. in the oven system, moving through it on a chain conveyor.
The use of the convection system alone had been unable to bring all sections of the complex products to optimum curing temperature. "We had to set the temperature higher than we wanted to in order to bring the product up to curing temperature. Most of the product never did reach the oven setting temperature [380°F]," Reinke said.
The new system has solved the plant's quality problem, reduced the oven's operating temperature, and avoided the need for facility changes.
Catalytic Industrial Systems, Independence, Kansas custom engineers and manufactures high-efficiency heating and oven equipment. For more information from Catalytic Industrial Systems, call (800) 835-0557; e-mail firstname.lastname@example.org or visit www.catalyticirovens.com.