Original Date: 06/29/1995
Revision Date: 01/18/2007
Best Practice : Deep Draw Metal Stamping
Wainwright’s deep draw stamping process for motor housing production has been successfully re-engineered and refined since 1985 (Figure 2-1). This process uses progressive tooling and requires two 400-ton presses and one 600-ton press for different motor housings. The capability to make the deep drawn housings using progressive tooling provides a significant cost advantage over Wainwright’s competition.
Examples of process enhancements include using a pre-coated material instead of plating the part after stamping. This had led to significant savings in lead time since the part does not have to be sent out for plating. The cleaning process has been improved with the addition of rust inhibitors in the cleaning solution to increase the parts’ shelf lives. The process has also been improved by performing the pre-rinse and the media tumbling in-line with the press, instead of in an off-line operation. Using the pre-coated material instead of plating afterwards has resulted in a 35% cost reduction that was passed on to the customer. Production lead time was also reduced from 8.75 days to 15 minutes.
The motor housing production rate is currently 425,000 parts per week of 10 different part numbers. In-die sensors have been installed for three part numbers, with more planned in the near future. The sensors detect the absence of any portion of the tool at each operation. The press can then be stopped before damage is done to the die by a portion of a broken tool progressing to the next stage of the process. In the six months since the sensors have been installed, ten instances of potential serious die damage have been averted. Returnable packaging material is recycled by Wainwright customers and is used on 225,000 housings per week.
Figure 2-1. Synchronous Organization Continuous Improvement Process
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