gaqyoo.blogg.se

Inherent random variations Consist of numerous small causes of random variability Management, operator, and engineering action will be necessary to eliminate the assignable causes.Įxhibit trend - make correction before process is out of controlĪ Process - A Repeatable Series of Steps Leading to a Specific Goalįluctuations not inherent to a process Represent problems to be corrected Data outside control limits or trend The control chart only detects assignable causes. If these causes can be eliminated from the process, variability will be reduced and the process will be improved 3. Consequently, the routine and attentive use of control charts will identify assignable causes. Most processes do not operate in a state of statistical control 2. Introduction to Control Charts Important uses of the control chart 1. Histograms do not take into account changes over time.Ĭontrol charts can tell us when a process changes poor employee training, worn tool, machine needing repair slight differences in process variables like diameter, weight, service time, temperatureĮ.g. Standard Deviation measures the amount of data dispersion around meanĮ.g. The Range- difference between largest/smallest observations in a set of data Top management commitment Project champion Initial workable project Employee education and training Accurate measurement system SPC Implementation Requirements      Helpful in identifying in-process variationsĪ methodology for monitoring a process to identify special causes of variation and signal the need to take corrective action when appropriate SPC relies on control charts

Quality characteristics are measured and charted Involves inspecting the output from a process

the mean, standard deviation, and rangeĭoes not help to catch in-process problems

Acceptance sampling used to randomly inspect a batch of goods to determine acceptance/rejection Į.g.