【正文】 actly where the next drop will land, we are reasonably confident it will fall somewhere on the “Common Cause” Highway. For this reason, a process that has only mon cause variation is said to be... STABLE and PREDICTABLE.A process with Special Causes might better be represented by a highway through an earthquake zone: likely to suddenly shift to the side by several feet or more. For this reason, a process that has Special Causes of variation is said to be... UNSTABLE and UNPREDICTABLE.227。2023, General Electric Company, USA. All rights reservedGE ConfidentialComponents of a Control ChartLower Control LimitCentral LineUpper Control Limit UCLLCLYaxis(Response)TIME227。2023, General Electric Company, USA. All rights reservedGE ConfidentialTracking process behavior by way of sample measurements (plotted points) can be thought of as being much like tracking a rabbit by way of its droppings. Suppose the footballshaped droppings fall at regular 1 minute intervals, and when they hit the ground, they tend to roll around a bit (like random/sampling variation).So the game bees, How to use statistical tools as reliable indicators to keep us from being fooled by the wobbling (noise) that will always be present in the droppings (data) so we reliably detect whether the rabbit did or did not move to the left or right of the straight path.When municating statistical concepts, you could describe SPC as follows:In case you might dare to use the idea one day...Here are some rules/principles to help us know when to react . . .227。2023, General Electric Company, USA. All rights reservedGE Confidential(1) Point beyond UCL or LCL (+/ 3 Std Dev’s)(2) 7 consecutive points on the same side of the centerline (Minitab uses 9)(3) Trend: 6 consecutive points steadily increasing or decreasing(4) Repeated patterns/cyclesHow to Detect a Change in Process Behavior:(., When an X just made an impact of the process)We can ask Minitab to search for 8 out of control conditions automatically227。2023, General Electric Company, USA. All rights reservedGE Confidential227。2023, General Electric Company, USA. All rights reservedGE Confidential XBar Range ChartforWheeler “Master” DataFile: “”Let’s see how we can plot 3 or 4 points….227。2023, General Electric Company, USA. All rights reservedGE Confidential227。2023, General Electric Company, USA. All rights reservedGE ConfidentialHere’s a blank XbarR chart (for future use)227。2023, General Electric Company, USA. All rights reservedGE ConfidentialThis is how a Control Chart actually looks using Minitab…227。2023, General Electric Company, USA. All rights reservedGE ConfidentialA subtle but crucial distinction: ?Control limits are not there to allow us to produce stuff within specifications they have nothing to do with tolerances in any way. ?Control limits are there only to allow the process to scream at us when an instability has occurred, in order to get someone off his/her rearend quickly enough to findout What just changed to cause that? while the tracks remain fresh before the evidence disappears forever. ?In this way, the limits help to prevent people from creating additional variation by tampering with a process that should have been left alone, and to keep people from wasting their time and effort looking around for What just changed? when there actually is no rational basis for being suspicious in the first place. ?Control limits, when established in a rational manner, are an operational definition for When to be suspicious.How to think about SPC:227。2023, General Electric Company, USA. All rights reservedGE Confidential謝謝觀看 /歡迎下載BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH