Quality Parts Company supplies gizmos for a computer manufacturer located a few miles away. The company produces two different models of gizmos in production runs ranging from 100 to 300 units.
The production flow of models X and Y is shown in Exhibit 14.14. Model Z requires milling as its first step, but otherwise follows the same flow pattern as X and Y. Skids can hold up to 20 gizmos at a time. Approximate times per unit by operation number and equipment setup times are shown in Exhibit 14.15.
Demand for gizmos from the computer company ranges between 125 and 175 per month, equally divided among X, Y, and Z. Subassembly builds up inventory early in the month to make certain that a buffer stock is always available. Raw materials and purchased parts for subassemblies each constitute 40 percent of the manufacturing cost of a gizmo. Both categories of parts are multiple-sourced from about 80 vendors and are delivered at random times. (Gizmos have 40 different part numbers.)
Scrap rates are about 10 percent at each operation, inventory turns twice yearly, employees are paid on a day rate, employee turnover is 25 percent per year, and net profit from operations is steady at 5 percent per year. Maintenance is performed as needed.
The manager of Quality Parts Company has been contemplating installing an automated ordering system to help control inventories and to âkeep the skids filled.â (She feels that two days of work in front of a workstation motivates the worker to produce at top speed.) She is also planning to add three inspectors to clean up the quality problem. Further, she is thinking about setting up
a rework line to speed repairs. Although she is pleased
with the high utilization of most of her equipment and labor, she is concerned about the idle time of the milling machine. Finally, she has asked the industrial engineering department to look into high-rise shelving to store parts coming off machine 4.
Questions
1. Which of the changes being considered by the manager of Quality Parts Company are counter to the lean philosophy?
2. Make recommendations for lean improvements in such areas as scheduling, layout, kanban, task groupings, and inventory. Use quantitative data as much as possible; state necessary assumptions.
3. Sketch the operation of a pull system for running Quality Parts Companyâs current system.
4. Outline a plan for introducing lean at Quality Parts Company.
exhibit 14.14 Gizmo Production Flow Machining Dept. Receciving Мachinc no. 1 Мachine no. 2 Mill Lathe Skid Table Tabke Machine no. 4 Machine no.3 Drill Skid Drill Tool crib Assembly Dept. Finishing Dept. Skid Skid 11 From To Oven ceiving assembly Skid 15 10 Skid Skid Subassembly arca for purchased parts gaing into final asse mbly Paint 6 booth 13 Skid Shipping Skid Skid Offices Operator Part-time worker Scak: 1/4" = 1 ft. Assembly bench Packing bench exhibit 14.15 Operations and Setup Time Operation Number and Name Operation Time (Minutes) Setup Time (Minutes) MIling for Model Z 1 Lathe 2 Mod. 14 drill 3 Mod. 14 drill 4 Assembly step 1 Assembly step 2 Assembly step 3 5 Inspection 6 Palnt 7 Oven 8 Packing 20 60 50 30 15 5 40 50 45 50 30 30 50 20 5
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