This project had the stated objective of improving the productivity and profitability of a large polyester processing plant located south of Columbia, South Carolina.
The primary area of focus within the plant transformed polyester pellets into polyester fiber. Examples of the eventual use of this fiber include filling for disposable diapers and polyester fabrics and yarns. The overall process involved heating the pellets into a liquid, then extruding the liquid into various deniers of polyester filament. The filaments were then cooled and twisted together, with up to thirty-nine other filaments, to form a length of yarn. This yarn was then joined with a number of comparable lengths of yarn to be later heated and crimped and, if for fabric or disposable diapers, finally chopped into small pieces.
The project was logically divided into three working areas: Extrusion, Processing, and Support Services (maintenance, waste recovery, and quality control).
Extrusion
The purpose of the Extrusion area was the conversion of polymer pellets into polyester filaments through a combination of heat and pressure. Each type of filament was assigned a specific lot number. This lot number dictated the melt temperature target to be used and the size of the holes through which the polymer was to be extruded.
During the course of the project, it became evident that the keys to productivity and profitability of the Extrusion area were as follows:
- the weight of the polymer pellets fed into the extruders;
- the number of extruders actually operating during each shift and production run;
- the amount of time which the extruders were out of production, individually and in aggregate;
- the temperature in the extruders;
- the proportion of time during which the extruder melt temperature varied from the specified temperature;
- the number of extruder filter changes which were required during each shift; and
- the number of production changes required during the shift.
After leaving the extruders and cooling, the filaments were joined with filaments from the other extruders on the same processing line and inventoried in large metal cans. Once the entire batch of the specific lot number was processed, the batch was transferred to the Processing area.
Processing
The Processing area is responsible for the final conversion of the polyester filaments into polyester fiber.
When each batch was ready for processing, the ends of each cord-like collection of filaments in the cans mentioned above were gathered together. The filaments were washed and heated. While hot, the filaments were crimped to ensure that the polyester fiber adhered to other types of fibers and textiles when they reach the customer. After drying, the fiber for fabric or diaper filling was cut into one-to-two inch pieces and baled.
As the project progressed, the following keys to the productivity and profitability of the Processing area were identified:
- the temperature at which the fiber was heated prior to crimping;
- the pressure at which the fiber was crimped;
- the amount of downtime experienced by the processing line;
- the speed of the processing line; and
- the quality of the filaments received from the Extrusion area as indicated primarily by the consistency of the melt temperature during the extrusion process.
Support Services
The two production departments depended on the support areas to provide such services as product quality analysis (post-production acceptance sampling), equipment maintenance, and technical improvements to maintain product quality, productivity, and utilization.
The Quality Services Laboratory was responsible for determining, on a timely basis, whether or not finished goods and their components met quality specifications.
The key indicators in the Lab were the turnaround time of the samples and the same-sample variance.
The Maintenance Department provided equipment maintenance, modifications and repairs to the production departments. Its chief responsibilities were to keep the production equipment running smoothly and to make technical improvements as identified.
The prioritization and timely, accurate completion of assigned work orders were found to be the critical factors in the Maintenance Department’s contribution to Division productivity and profitability.
Project Results
The premise under which the project team operated was that a primary cause of sub-optimal productivity and profitability was lack of control. Within the client organization, management felt responsible for continually seeking ways to employ its assets and resources toward the improvement of its products, its methods of production, and the profitability of its business unit. Each of the various layers of management within the organization had different resources available to it yet each had the responsibility for the proper management of those resources.
Given the premise and the degree of responsibility felt by Division management, the project team proceeded to develop tools necessary to enable each layer of management to be more effective in their work. These tools allowed plant supervision and management to not only assign work, check quality, ensure that people and equipment were “moving,” and to report results, but also to plan, organize, and schedule the work and to anticipate, prevent, identify, and reduce the impact of operating problems.
The system of tools developed to achieve this included the following:
- the ability to correlate operating and quality problems in one department with those in another; and
- the ability to accurately pinpoint specific root causes of operating problems so that they could be systematically eliminated.
Project results included the following:
- an increase in Extrusion department attainment versus plan from 91% to 97% in less than six months;
- a reduction in Extrusion department unscheduled downtime from 6.5% to 2% in less than six months; and
- a reduction in processing line operating time by over two hundred hours per week despite an increase in average weekly production from 3.8 million pounds to 4.5 million pounds (mostly through reduction in scrap and re-work) in an operating unit that had historically experienced more demand than they could meet.
The decreased labor was valued in excess of one million dollars annually. The increase in effective capacity was valued at approximately $700,000 weekly in revenue with no increase in raw materials and the reduction in labor.