Lean Production

Lean Production of Paper Airplanes

 Example: Assume that you and another person are tasked with making a large number of paper airplanes. Each unit requires three operations: (1) marking, (2) cutting, and (3) folding.

Describe the mass and lean ways to deploy your resources. Which might generate airplanes with higher quality?

Solution:A mass production method would be to have one person doing all the marking and cutting and the other person doing all the folding. The lean way would have both people doing marking, cutting, and folding to make complete airplanes. The lean way would probably produce higher quality because, during folding, people might detect issues in marking and cutting. That information would be used the next time to improve marking and cutting with no possible loss associated with communication. (Mass production might produce units more quickly, however.)

In addition to studying Toyota’s lean production, observers compare many types of business practices at European, Japanese, and U.S. companies. One finding at specific companies related to the timing of design changes at automotive companies. In the automotive industry, “Job 1” is the time when the first production car roles off the line. A picture emerged,  implies that at certain automotive companies in Japan, much more effort was spent investigating possible design changes long before Job 1. At certain U.S. car companies, much more of the effort was devoted after Job 1 reacting to problems experience by customers. This occurred for a variety of reasons. Certain Japanese companies made an effort to institutionalize a forward-looking design process with “design freezes” that were taken seriously by all involved. Also, engineers at these specific companies in Japan were applying design of experiments (DOE) and other formalized problem-solving methods more frequently than their U.S. counterparts. These techniques permit the thorough exploration of large numbers of alternatives long before Job 1, giving people more confidence in the design decisions.

Another development in the history of quality is “miniaturization”. Many manufactured items in the early 2000s have literally millions of critical characteristics, all of which must conform to specifications in order for the units to yield acceptable performance. The phrase “mass customization” refers to efforts to tailor thousands of items such as cars or hamburgers to specific customers’ needs. Mass customization, like miniaturization, plays an important role in the modern work environment. Ford’s motto was, “You can have any color car as long as it is black.” In the era of global competition, customers more than ever demand units made to their exact specifications. Therefore, in modern production, customers introduce additional variation to the variation created by the production process.

ExampleFreezing Designs

With respect to manufacturing, how can freezing designs help quality?

Solution:Often the quality problem is associated with only a small fraction of units that are not performing as expected. Therefore, the problem must relate to something different that happened to those units, i.e., some variation in the production system. Historically, engineers “tweaking” designs has proved to be a major source of variation and thus a cause of quality problems.