To provide a rational means to categorize (common cause vs special cause) and measure variation, Walter A. Shewhart invented control charts circa 1925 – 1931. W. Edwards Deming took these basic statistical concepts and tools with him to Japan after World War II and planted the seeds for the quality revolution. The rest is history. […]
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Common Cause vs Special Cause
All manufacturing and business processes contain many sources of variation. The differences may be so small as to be difficult to detect, but they are there. Variation is at the root of all waste. Less variation, less waste. To reduce variation, and effectively solve problems, its sources must first be understood as common cause vs […]
Best Constraint Location
In my previous blog on Theory of Constraints, I defined the constraint (aka, the bottleneck) as the weak link in the chain. Every system has one. If there is a choice, where is the best constraint location? The Ugly. By far the worst place to have the constraint is in the marketplace. When the constraint […]
5-Step Throughput Improvement Model
In my previous blog, I used the “ten machine” manufacturing puzzle to establish the need to think systemically: in isolation each machine hit its performance target, in combination the system failed to reach its goal. The 5-Step Throughput Improvement Model is a proven process to solve this local optimization paradox. Theory of Constraints views an […]
Theory of Constraints
“In isolation yes, in combination no” is a key concept in Theory of Constraints and bottleneck analysis. Consider the ten machine manufacturing process in the schematic below. Each machine had a team of manufacturing engineers managing their design and development. All ten teams hit their performance target: 50 units per hour and 98% availability. A […]