25.08.2019
 Essay upon X-Chart and P-Chart

PROBLEMS

2 . Control charts for X and Ur are to be proven on a selected dimension component, measured in millimeters. Data were accumulated in subgroup sizes of 6 and are given below. Determine the trial central series and control limits. Assume assignable triggers and change the central line and limits.

|SUBGROUP NUMBER |Xbar |R |SUBGROUP NUMBER |Xbar |R | | |20. 35 |0. 34 | 14. |20. 41 |0. 36 | | |20. 40 |0. 36 | 15. |20. 45 |0. 34 | | |20. 36 |0. 32 |16. |20. thirty four |0. thirty eight | | |20. sixty-five |0. thirty-six |17. |20. 36 |0. 37 | | |20. 20 |0. 36 |18. |20. 40 |0. 73 | | |20. 40 |0. thirty five |19. |20. 50 |0. 38 | | |20. 43 |0. 31 |20. |20. thirty-one |0. thirty five | | |20. thirty seven |0. thirty four |21. |20. 39 |0. 38 | | |20. 48 |0. 30 |22. |20. 39 |0. thirty-three | | |20. forty two |0. 37 |23. |20. 40 |0. 32 | | |20. 39 |0. 29 |24. |20. 41 |0. 34 | | |20. 35 |0. 40 |25. |20. 40 |0. 30 | | |20. 40 |0. 33 | | |

_

[pic] = 510. 01R sama dengan 8. fifth 89

twenty-five 25

sama dengan 20. 40mm = 0. 3556mm

By Table B in the appendix, the ideals for the factors for 6 subgroup size (n) of ur are A2 = 0. 483, D4 = 2 . 004, D 3 = 0. Trial control limits for the Times chart happen to be

UCLxbar = 20. 45 + A2R bar LCLxbar = 20. 40 -- A2R pub

sama dengan 20. 40+ (0. 483) (0. 3556) = 20. 40- (0. 483) (0. 3556)

= 20. 57mm = 20. 23mm

Trial control limits to get the L chart will be

UCLR sama dengan D4R LCL R sama dengan D3R

= (2. 004) (0. 3556) = (0) (0. 3556)

= zero. 71 millimeter = 0 mm

Revise the central line and limits:

a) One among point is definitely outside control limit (mean of subgroup number 4 (20. 65mm) above UCL x-chart (20. 57mm) / range of subgroup number 18 (0. 73mm) above UCL R-chart (0. 71mm). This can be showed that this process is out of control. The special cause variation is out there in this x-chart.

Assume assignable causes are machine specialized problem or bad material. 3. The following table provides the average and range in kilograms intended for tensile testing on an superior plastic power cord. The subgroup size is four. Determine the trial central line and control restrictions. Of any points happen to be out of control, presume assignable triggers and estimate revised restrictions and central line.

|SUBGROUP NUMBER |Xbar |R |SUBGROUP NUMBER |Xbar |R | | |476 |32 | 14. |482 |22 | | |466 |24 | 15. |506 |23 | | |484...