Polyhedrika

  The first step for process improvement is stability. We analyse this with Statistical Process Control . As a result of this analysis we may find out-of-control situations due to special causes. We need to resolve these causes to make the process stable.  Stability means the process is behaving in a predictable way but it doesn't necessarily mean it meets the customer expectations.  To find out to what extent is the process able to meet the customer expectations we measure Process Capability . Descriptive Statistics with Excel Download a copy of Excel file   Capability.xlsx   from OneDrive on to your PC to run it. In sheet Diameter  we have placed in column A our data consisting of 500 measurements of a critical diameter. After being confident that our process is stable we can characterize it with descriptive statistics in Excel Data Analysis:   These are the results: basic statistics of our data  Frequency Distribution Histogram The histo...

Analyzing our Value Stream we identify a number of constraints that limit its effective capacity. The most visible constraints are the capacity of the different steps. But there are other, not so obvious, constraints such as the capacity variation of some steps. Process variation has been described as a virus infecting the value stream: it causes chaos and it is often undetected.     Dice Throwing Exercise A bottleneck limits the effective capacity of the whole line. Bottlenecks caused by variation are more subtle and difficult to detect and act upon. Process simulation can help us experience the effects of different types of constraints, try solutions and detect possible side effects. Process simulation helps us understand the value stream dynamic behavior: how variation affects key process metrics such as WIP, Lead time, Throughput, Cycle time, On Time Delivery, etc. Understanding these dynamic effects will enable us to get to the root cause of problems implementing def...