Quality Parts
Which of the changes being considered by the manager of Quality Parts Company are counter to the JIT philosophy?
The most conspicuous proposed change is the manager's request that the industrial engineering department look into high-rise shelving to store parts coming off machine 4. Any parts coming off of any machine, not just machine 4, should be immediately sent to the next machine for further processing. Even though a 10% scrap rate is inordinately high, she should hold off on the rework line as this adds an additional level of complexity to the process, which is certainly counter to the JIT philosophy. More specifically, if it is only being used to remanufacture 10% of the factory's output (10% being the scrap rate), look at how much more floor space (a scarce resource that needs to be maximized) is going to be required just to solve that 10% problem -- with no guarantees that all 10% of the scrapped units can be successfully remanufactured. If her quality control efforts pay off, a rework line won't be necessary anyway. That's the third thing -- the quality control inspectors. If she is serious about solving the quality control problem, she needs to think about re-designing the assembly process to minimize the number of times people have to touch the parts; this is almost always where the problems enter that lead to...
These are then stored.
2. Make recommendations for JIT improvements in such areas as scheduling, layout, kanban, task groupings, and inventory. Use quantitative data as much as possible; state necessary assumptions.
The machines requiring setup times are the mill, lathe, the two drills, and the paint booth. Since they can be setup concurrently, and since the mill and lathe require the most setup time, on days in which production starts with Gizmo Z (Gz), the maximum setup time for the whole assembly line is 60 minutes, and 30 minutes on days in which production starts with either Gizmo X (Gx) or Gizmo Y (Gy). Actual manufacturing times for Gx and Gy are therefore 395 minutes (6.58 hours) for the first unit of each, and 445 minutes (7.42 hours) for the first unit of Gz. Thereafter, since there is no manufacturing step longer than 50 minutes, the assembly line can produce 1 Gizmo every 50 minutes. This assumes that the paint booth and oven can each operate on only 1 unit at a time. If we also assume that the factory operates continuously for 24 hours daily and 7 days weekly, it can produce the minimum and maximum quantities ordered by the customer in only 123.08 hours (5.13 days)…
