Proper Group International’s automotive specialty landed the company a large multi-national, tier one supplier who was challenged with meeting a very aggressive piece price and capital budget for an automotive front and rear door module program. According to Proper’s Joe Grippe, Vice President Sales and Marketing, the customer’s choices for part production were to build two conventional 1 + 1 cavity molds, which would require molding in a 2500 to 3000 Ton press; or to build four single-cavity molds to run in multiple 1200-ton machines. In each case, the piece price was not going to be acceptable for the targets the OEM had set, Grippe notes.
“We engaged with the customer to discuss the possibility of building two 1+1 cavity stack molds, which would run in 1500-ton presses,” Grippe elaborates. “Stack molds have been used in a number of industries to produce high volumes of parts of relatively low complexity. In this case, we were looking at highly complex, thin-wall interior parts with actions on the cavity and core. In addition, the material was a high glass content—an engineered resin that ultimately had to meet very stringent flatness tolerance once molded.”
Proper developed a business case that weighed building the stack molds against building the conventional, 1+1 cavity molds. In this business case, we factored in the piece price impact to mold the product in a 1500-ton press versus a 3000-ton press. “The annual volume of the program was projected to be 180,000 vehicles annually (720,000 doors),” Grippe says. “The upcharge for each stack mold was approximately $80,000 over the conventional 1 + 1 molds,” he states. “The difference in piece price as a result of running in a 1500 ton verses a 3000 ton, represented a savings of approximately $1.05 per part. Stack tooling offers this benefit by optimizing the required injection tonnage by placing symmetrically opposite parts on top of one another in mold position, opposed to next to one another in conventional mold position.”
Proper Tooling built two stack molds, one for the front door and one for the rear door. “The total upcharge for the tooling was $160,000,” Grippe notes. “The annual piece price savings was $756,000. This program is projected to run for five years. So, the life of the program savings is projected to be $3,780,000.00. This produced a return on investment on the upcharges to the mold for our customer inside five months.”