Original Date: 06/26/1995
Revision Date: 01/18/2007

Dayton Parts, Inc. (DPI) assembled a team to investigate problems with and initiate continuous improvements to its Hille Computerized Hot Rolling Taper Mill. Used in the production of tapered spring products, the Hille machine represented a production bottleneck, while business projections in 1992 indicated significant growth would occur in the tapered spring market. Because between $1.5M and $2.0M was projected to be required to purchase additional taper rolling capacity, DPI management decided to assemble a continuous improvement team to investigate problems with the existing machine.

The team was initially led by the Director of Manufacturing and included members from engineering, maintenance, and the Hille operators’ group. The team’s stated mission was to continuously improve the machine availability and production output. Data was collected and charted to show key factors such as average ends per shift, set-up hours, downtime hours, material handling hours, and maintenance by operators. A Pareto analysis was performed looking at every element contributing to downtime on the machine. Problems contributing most to the bottleneck problem were addressed first. For example, the initial analysis highlighted a major problem with hydraulic leaks. These were corrected by designing and installing two new seamless piping lines. The leak correction also reduced the disposal of used oil by six to eight drums per quarter.

Another major contributor to the reduced production capacity of the Hille machine was in set-up time requirements. Major line set-up changes required four hours, and average set-up across the entire spectrum was 30 minutes. The team investigated quick-die change systems and worked with vendors to develop a system for the Hille. A new system was developed and installed at a total cost of $149.1K. Installation of the system was projected at two weeks but only required four days from transport arrival to full production running. This was attributed to team familiarity with the new system. Since its implementation, overall average set-up has dropped to as low as 18 minutes, and the four-hour major set-up has been reduced to 30 minutes. As a result of these improvements, the Hille is no longer a bottleneck and now contributes to the overall throughput improvement that the company is experiencing. Improvements to the machine and its operations have increased capacity to meet an even larger growth than anticipated, and it is expected to meet additional future requirements.

The team continues to monitor data and implement changes that impact the operational capability of the Hille machine. The results achieved by this team not only allowed the company to avoid a major capital equipment investment, but also provided the opportunity to demonstrate how employee involvement in continuous improvement activities can have a major impact on the company’s overall business outlook.

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