Sharon Johnson, WPI, email: sharon@wpi.edu
Michael Elmes, WPI
- To involve students in a lead time reduction exercise, which illustrates a number of methodologies for reducing lead time (e.g. identifying bottlenecks, material control though kanban, and setup time reduction).
- To illustrate to students the critical role that measurement can play in improvement efforts, and the value of good information for production planning.
- To allow students to explore the role that culture, and particular organizational structures, play in process improvement efforts.
- To encourage students to consider how such improvement efforts can be transferred to other locations and projects.
- To build students' communication skills, and their confidence in their technical expertise.
This case focuses on the reduction of interval (lead time) in the Patriot Shop at AT&T during 1991 through 1993. During this period, the Patriot Shop produced approximately 350 different circuit packs for three product lines, and reduced interval from approximately 8 weeks to less than 2 weeks. Impetus for the reduction came from an unexpected surge in demand. The interval reduction began by identifying an appropriate metric, then using this metric to develop streamlined reports that proved to be extremely useful for decision-making. The reports pulled in information from two MRP systems, as well as information from the shop floor. Next, the team identified bottlenecks in the process flow, which were sensitive to the product mix. Progressive assembly, kanbans, and setup reduction were then used at different points in the process to attack bottlenecks, and reduce confusion on the shop floor. The skills and enthusiasm of process engineers, managers, and shop floor personnel were key success factors in the improvement effort.
The case is organized into several modules, which can be used individually or as a sequence:
- The first module provides background on the Patriot shop, describes the production process and asks students to consider the dilemma of Maurice Henderson, Focus Factory Director of Diversified Products at AT&T's manufacturing facility, who has initiated an interval reduction program and must now provide direction on how to implement it.
- In the second module, which occurs six months later in the setting of a production planning meeting, students learn that AT&T began their interval reduction effort by developing simple reports to highlight and pull together important information. A number of suggestions for reducing interval are also presented. Students are then asked to carry out analyses to improve particular bottlenecks, and as a class to determine which project(s) should have the greatest priority. For example, dedicating heads on machines in the sequence area reduced the amount of setup time required to place unique components on circuit packs. Students are given data on demand and sequences, and asked to make the head assignments. Other student groups are responsible for developing lot-sizing rules, kanbans, a more efficient layout, or progressive assembly lines.
- In the third module, which takes place two years later, students are asked to examine the cultural and structural factors which contributed to the project's success, and discuss how these improvements could be transferred to other manufacturing settings.
Case Study
Upper level undergraduate students in Industrial and Manufacturing Engineering, MBA students.
MG 3401 - Production Planning and Control, B-term (October-December) 1996, 50 students. Aspects of the case could also be presented in an organizational behavior course.
4 hours of class time (1 hour each for modules 1 and 3; 2 hours for module 2), 7-12 hours homework (1 hour each for modules 1 and 3; 5-10 for module 2).
Case, Instructor's Manual, Spreadsheets with data and models.
In development.
Spreadsheet. May be some additional requirements as the case is developed.
Presentation at Cornell Workshop on Experiential Learning in Manufacturing System Design.