Wednesday, April 29th, 2009

What is Six Sigma?The concepts surrounding the drive to Six Sigma quality are essentially those of statistics and probability. In simple language, these concepts boil down to, “How confident can I be that what I planned to happen actually will happen?” Basically, the concept of Six Sigma deals with measuring and improving how close we come to delivering on what we planned to do.Anything we do varies, even if only slightly, from the plan. Since no result can exactly match our intention, we usually think in terms of ranges of acceptability for whatever we plan to do. Those ranges of acceptability (or tolerance limits) respond to the intended use of the product of our labors–the needs and expectations of the customer.Here’s an example. Consider how your tolerance limits might be structured to respond to customer expectations in these two instructions:“Cut two medium potatoes into quarter-inch cubes.” and “Drill and tap two quarter-inch holes in carbon steel brackets.”What would be your range of acceptability–or tolerances–for the value quarter-inch? (Hint: a 5/16” potato cube probably would be acceptable; a 5/16”threaded hole probably would not.)Another consideration in your manufacture of potato cubes and holes would be the inherent capability of the way you produce the quarter inch dimension–the capability of the process. Are you hand-slicing ...
Tags: Sigma Quality, Standard Deviations, Steel Brackets
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