Sunday, October 23rd, 2016
Deming’s Principle of Management n. 3 full statement is as follows:
“Eliminate the need for mass inspection as a way to achieve quality by building quality into the product in the first place. Require statistical evidence of built-in quality in both manufacturing and purchasing functions.”
Dependence on inspection means there are two systems at work. One that makes defective product and another that tries to protect your customers from the inadequacies of the first. The inspection process falls down whichever way you look at it. On the one hand, defective product might easily evade the inspectors and get through to your customers. On the other hand, even if it is entirely successful in picking out defects, why should customers have to pay for this additional system, when you should be striving to eliminate the problems at source?
Quality comes improving the process, not from inspecting the finished goods at the end of the production process, then discarding those items that failed to meet specifications.
The best environment for reducing the need for final inspection arises when individuals are aware of, and responsible for the quality of, the processes by which they do their own work.
Deming once told the apocryphal story of two Western industrialists holding a breakfast meeting. One said, “Let’s make toast. You burn and I’ll scrape”. – But we all know that burnt toast never tastes as good as toast made properly in the first place.
Summing-up: Inspections are costly and unreliable – and they don’t improve quality, they merely find a lack of quality. Build quality into the process from start to finish. Don’t just find what you did wrong – eliminate the “wrongs” altogether. Use statistical control methods – not physical inspections alone – to prove that the process is working.