Casting of the Year
Alternator/Air Conditioning Bracket Dotson Iron Castings, Mankato, Minnesota
Material: Ductile iron. Process: Green sand. Weight: 10.7 lbs. Dimensions: 15 x 6 x 5 in. Application: Skid loader engine bracket. Converted from: 11-piece steel weldment.
manufacturing company. “I sit in the factory next to the as-
R
sembly line and offer tactical support,” he said. “If there is a problem with a part, I see that.” That’s just the beginning of what
Vonnahme does, but simply sitting near the assembly line and watching the way it operates was a critical step in a recent casting conversion that eventu- ally slashed the cost of an alternator/ air conditioning bracket that fi ts on a Deere skid loader. What Vonnahme noticed during
MODERN CASTING / June 2010
on Vonnahme, a design en- gineer for John Deere, Mo- line, Ill., has a humble way of describing his position with the heavy equipment
• The bracket is used to mount a 12-lb. high output alternator and 14-lb. air conditioning condenser to the engine of a John Deere skid loader.
• The component offered 48% cost savings, accuracy improvements and better space utilization over the steel weldment it replaced.
• The customer realized a 10% reduction in scrap on its skid loader assembly line over its welded predecessor.
the skid loader’s assembly was that a weldment used to mount a 12-lb. high output alternator and 14-lb. air condi- tioner compressor to the engine was being scrapped at the line repeatedly. That’s too late to be fi nding defective parts, he said, but it was diffi cult to determine just who—or what—was at fault in the supply chain. “The supplier made sure they made a good part,” Vonnahme said. In the end, it wasn’t human error
but process error. The original weld- ment consisted of 11 pieces of steel stock. Because the pieces had to be machined prior to welding, the com- ponent required eight different set-ups for profi le sizing and machining. The bracket also required four unique angle
bends. With so many processing steps, even slight variations in machining, angle bending and welding resulted in a dimensionally inaccurate part and all the scrap that was ending up at the Deere assembly line. “It never should have been a fabri- cated part,” Vonnahme said. Vonnahme didn’t know immediately
what the part should have been, but another Deere designer with experi- ence working with metal castings did. And by collaborating with a machine shop with which Deere works on a number of components and metalcaster Dotson Iron Castings, Mankato, Minn., the company eventually replaced the weldment with a one-piece green sand casting that reduced the bracket’s piece
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