The thought of proof by contradictionOnce the dots go beyond the boundary lines of thecontrol chart or other small probability events happen, wewill suspect that the original production process is out ofcontrol, that is not stable, at themoment,we need to findthe reason from 5MiE,and see whether significant changeshavetakenplace.2007.4The thought of proof by contradiction21
The thought of proof by contradiction 2007.4 Once the dots go beyond the boundary lines of the control chart or other small probability events happen, we will suspect that the original production process is out of control, that is not stable, at the moment,we need to find the reason from 5M1E,and see whether significant changes have taken place. The thought of proof by contradiction 21
It's suitable for the condition that the productquality characteristics is the measuring values.Suchas length,weight,time,strength,composition andother continuous variables.The common attributescontrol charts have the following:1. X-bar and Rcontrol chart (x-R chart)2. Median-range control chart (X - R chart)3.Single value-moving range control chart (x-R,chart)4.X-barand S control chart (x-Schart)2007.4Attributes control charts22
Attributes 2007.4 control charts It's suitable for the condition that the product quality characteristics is the measuring values.Such as length,weight,time,strength,composition and other continuous variables.The common attributes control charts have the following: 1. X-bar and Rcontrol chart（ chart） 2. Median-range control chart（ chart） 3. Single value-moving range control chart（ chart） 4. X-bar and S control chart（ chart） x − R x − R ~ Rs x − x − S 22
It's suitable for the condition that the productquality characteristics is the measuring values.Such as number of defectives,fraction defective.number of defects,defects per unit and otherdiscrete yariable.The common attributes controlcharts have the following:1.Control chart forfraction defective (P chart)2. Control chart for number of defectives (Pn chart )3. Control chart for defects per unit （u chart)4.Control chart for number of defects (c chart)2007.4Attributes Control Charts23
2007.4 Attributes Control Charts It's suitable for the condition that the product quality characteristics is the measuring values. Such as number of defectives,fraction defective, number of defects,defects per unit and other discrete variable.The common attributes control charts have the following: 1. Control chart for fraction defective（Ｐchart ） 2. Control chart for number of defectives（Pn chart ） 3. Control chart for defects per unit（ u chart ） 4. Control chart for number of defects（c chart ） 23
X - Rchart is a control chart that X Chart is used incombination withR Chart;XChart is mainly used to judge whether the average ofthe production process is in or to maintain the requiredcontrolled state,and the sensitive ability of X Chart thatfinds anomaly is better than individual X chart;R chart is mainly used to judge whether the standarddeviation of the production process is in or to maintain therequired controlled state;X Rhart is usually used when the sample size is smalland it is one of themost common attributes control charts:Generally, n = 3, 4, 5, and 6 are advisable2007.4X-bar and Rcontrol chart24
X 2007.4 -bar and Rcontrol chart chart is a control chart that Chart is used in combination with R Chart; R chart is mainly used to judge whether the standard deviation of the production process is in or to maintain the required controlled state; Chart is mainly used to judge whether the average of the production process is in or to maintain the required controlled state, and the sensitive ability of Chart that finds anomaly is better than individual X chart; X − R X chart is usually used when the sample size is small, and it is one of the most common attributes control charts; Generally, n = 3, 4, 5, and 6 are advisable. X − R X 24 X
-37/dam)UCL = x+30=X+A,RNn=xChartCL = xLCL = x-A,RUCL=R+3d;=R+ 3d,R=D4RRChartCL= R2007.4CThe parameters of Control Chart25
The parameters of C 2007.4 ontrol Chart = − == + = + = + LCL x A R CL x x A R d n x R n UCL x x C 2 2 2 ( ) 3 3 hart == + = + = CL R D R d d R UCL R d R RChart 4 2 3 3 3 3 25