Original Date: 07/23/1996
Revision Date: 01/18/2007
Best Practice : Quick Mold Change
Nascote, as a high production supplier of automobile parts to several manufacturers, accommodated almost 900 tooling changes per year at 1.8 hours per change. To decrease the tooling change time and increase productivity, a team was formed with a superintendent, supervisor, technician and one tool changer from each shift to determine how to reduce the required time for changing molds weighing in excess of 30 tons.
The team applied an “As Is” analysis technique. First, the team mapped a common tool change through each team member explaining his/her specific role during the tool change. The next step required the accurate timing of an actual tool change, noting all problems encountered during the change process. The process reflected the 1.8 hours needed to complete a mold change from the last part of the previous tool to the first acceptable part of the subsequent tool. This figure became the corporate baseline for process improvement initiatives.
The “As Is” analysis also reflected:
Twelve steps within the current process A 20-minute delay while the mold was brought to operating temperature
Employees involved in the change process had limited skills
Variety of hose lengths were needed for the water connection
Ergonomic implications from attaching 30-pound swivels above waist level
Slippage from fluids lost during mold changes created safety concerns
Irregular regulator and electrical connections
Markings for connections needed to be made
16 large bolts were needed to secure the mold to the press
60-pound impact gun was needed to secure these bolts
Tool changer had to lay on his/her back under the mold
Acquiring the initial location of the mold on the stationary platen was difficult
Physical arrangement of the tool changer’s tool box was important
Inability to locate the tool changer due to rotational assignments was a problem
Scheduling did not provide ample notice for change preparation
Armed with management’s endorsement and a 30-day time line for implementation, the team developed a four-day, continuous process improvement plan. Each task was assigned to one or two members for action with a milestone for completion. The team met on a regular basis to monitor progress and provide resolution of problems encountered during the improvement process. To better develop a target of improvement, the team benchmarked two companies with a similar product line and mix.
As a result of its commitment, Nascote has become the model for companies of similar size, product, and part mix. The findings of the “As Is” state have provided the company with the “Perfect” state, or current six-step process. In addition, using an existing pre-heater eliminates the 20-minute heating delay, and mold changers are trained to open and close the press instead of a technician. There are common locations and hard connections for water connections to allow standardized hose lengths. Swivels are delivered prior to the molds to reduce handling, and non-slip surfaces reduce possible injuries. Regulator and electrical connections are positioned at the same location on each mold, and all water connections are marked “in” and “out” to eliminate connection errors. Hydraulic clamps have been designed to eliminate the 16 mounting bolts, and a more suitable impact gun has been procured. Common connection locations have eliminated the need for tool changers to lie on their backs under the molds during the change process, and location positions painted on the stationary platen have simplified the initial location of the mold. The company purchased a new cart for the tool changer’s tools and tools to be ergonomically located. Tool changers have been reassigned to the re-grind room to make them accessible without disrupting the product flow. And finally, scheduling has been prepared to provide a two-hour notice to allow sufficient change preparation.
The changes implemented resulted in a process with a completion time of less than 0.52 hours, reflecting a savings of 1.28 hours per mold change. This savings, multiplied by the number of tool changes performed, netted a dollar savings of $215,040 per year. The increased capacity now available effected a cost avoidance of $3 million because an additional molding press purchase was no longer necessary. Faster tooling changes also reduced the company’s product inventory. With an improvement of this magnitude, Nascote has now changed its Tool Specification Book to ensure all future molds procured are designed for their “Perfect” state tool change process.
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