1. Consider the principles of the Toyota Production System (TPS, which the rest of the world calls just-in-time or lean operations). How do its pieces fit together into a strategic capability? In particular, what are the roles of quality, and of the various activities Toyota pursues to improve quality?
Waste reduction is at the top of the TPS architecture. The methods that help support the goal of waste reduction are JIT (just-in-time) and quality improvement methods. Both require standardization of work to eliminate variability, the flexibility to scale up and down process capacity in response to fluctuations in demand, and a set of human resource management practices.
JIT seeks to ...view middle of the document...
There are two forms of process control in this system:
a. Kanban-based pull: the upstream replenishes what demand has withdrawn from downstream
b. Make-to-order: work is released into a system only when a customer order has been received for that unit
TPS’ emphasis on quality lets Toyota overcome the buffer-or-suffer tension: by producing with zero defects and zero breakdowns, the company neither has to suffer (sacrifice flow rate) nor to buffer (hold excess inventory). To achieve few defects, TPS relies on the following:
1. Defect prevention: Components are designed in a way that there exists one single way of assembling them giving very little room for error.
2. Rapid defect detection: The idea of jidoka is to stop the process immediately whenever a defect is detected and to alert the line supervisor. A defective machine should shut itself off automatically in the presence of a defect. Shutting down the machine forces a human intervention in the process, which in turn triggers process improvement.
3. Strong worker responsibility with respect to quality: Every resource should only let those flow units move downstream that have been inspected and evaluated as good parts. Quality inspection is ‘built-in’ and happens at every step on the line as opposed to relying on a final inspection step alone. Additionally, quality circles bring workers together to jointly solve production problems and to continuously improve the process. Like the production process, the process of improvement is standardized.
2. Does Toyota respond to customer orders in a “just-in-time” way? What steps of production do they do just-in-time?
Toyota has a ‘just-in-time’ response to customer orders depending on the type of order. One form of the pull system is the make-to-order process in which resources in a process only operate after having received an explicit customer order. Typically, the products corresponding to these orders then flow through the process on a first-in, first-out basis. Make-to-order should be used when (a) products or parts are processed in low volume and high variety, (b) customers are willing to wait for their order, and (c) it is expensive or difficult to store the flow units.
3. What are the pros and cons of mixed-model assembly (i.e., making a mix of products on the line at one time)?
Mixed-model assembly is designed to avoid large batches of the same variant. Spreading out the demand for parts as evenly as possible relieves suppliers of a surge of workload and facilitates their JIT production. Offsetting cars that required a particular operation against those that did not prevents any particular work station from becoming a severe bottleneck or remaining unreasonable idle. While a disadvantage of mixed-model assembly is that it may complicate line operations to some extent, it serves the purpose of simplifying upstream operations. Another disadvantage of mixed-model assembly happens when the setup time occurs at...