j5124 Assignment 2 Dec 2010
1
JOHOR BAHRU POLYTECHNIC DEPARTMENT OF MECHANICAL ENGINEERING Km 10, Jalan Kong Kong, 81700 Pasir Gudang, Johor DT. Tel: 07-2611715 Fax : 07-2612402 ______________________________________________________________________________________________________________ Course : J5124 Quality Control Lecturer Name: Mr. Yap Tek Hong Type Of Assessment: Assignment 2 Programme : DKM 6A Session: December 2010 Date Of Assignment : 26/1/2011 Due Date For Assignment: 9/2/2011 INSTRUCTION i. This task is individual assignments. ii. This task consists of 2 essay questions. iii. Answer all questions. QUESTION 1 The following table gives the average and range in kilograms for tensile tests on an improved plastic cord. The subgroup size is 4. SUBGROUP NUMBER X R SUBGROUP NUMBER X R 1 476 32 14 482 22 2 466 24 15 506 23 2 484 32 16 496 23 4 466 26 17 478 25 5 470 24 18 484 24 6 494 24 19 506 23 7 486 28 20 476 25 8 496 23 21 485 29 9 488 24 22 490 25 10 482 26 23 463 22 11 498 25 24 469 27 12 464 24 25 474 22 13 484 24 i. Determine the trial central line and control limits for the X and R chart. ii. Sketch the X and R chart. iii. If any points are out of control, calculate revised central line and limits iv. Also determine the process capability of the tensile tests of the improved plastic cord.. QUESTION 2 Control charts for X and σ are to be established on the Brinell hardness of hardened tool steel in kilograms per square millimeter. Data for subgroup sizes of 8 are shown below:- SUBGROUP NUMBER X σ SUBGROUP NUMBER X σ 1 540 26 14 551 24 2 534 23 15 522 29 2 545 24 16 579 26 4 561 27 17 549 28 5 576 25 18 508 23 6 523 50 19 569 22 7 571 29 20 574 28 8 547 29 21 563 33 9 584 23 22 561 23 10 552 24 23 548 25 11 541 28 24 556 27 12 545 25 25 553 23 13 546 26 i. Determine the trial central line and control limits for the X and σ chart. ii. Sketch the X and σ chart. iii. Assume that the out-of-control points have assignable causes. Calculate the revised limits and central line. iv. Also calculate the process capability of the case-hardening process.
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Transcript of j5124 Assignment 2 Dec 2010
JOHOR BAHRU POLYTECHNIC DEPARTMENT OF MECHANICAL ENGINEERING
Km 10, Jalan Kong Kong, 81700 Pasir Gudang, Johor DT. Tel: 07-2611715 Fax : 07-2612402 ______________________________________________________________________________________________________________ Course : J5124 Quality Control Lecturer Name: Mr. Yap Tek Hong Type Of Assessment: Assignment 2
Programme : DKM 6A Session: December 2010
Date Of Assignment : 26/1/2011 Due Date For Assignment: 9/2/2011
INSTRUCTION i. This task is individual assignments. ii. This task consists of 2 essay questions. iii. Answer all questions.
QUESTION 1
The following table gives the average and range in kilograms for tensile tests on an improved plastic cord. The subgroup size is 4.
SUBGROUP
NUMBER X R SUBGROUP
NUMBER X R
1 476 32 14 482 22 2 466 24 15 506 23 2 484 32 16 496 23 4 466 26 17 478 25 5 470 24 18 484 24 6 494 24 19 506 23
7 486 28 20 476 25 8 496 23 21 485 29 9 488 24 22 490 25 10 482 26 23 463 22 11 498 25 24 469 27 12 464 24 25 474 22 13 484 24
i. Determine the trial central line and control limits for the X and R chart.
ii. Sketch the X and R chart.
iii. If any points are out of control, calculate revised central line and limits iv. Also determine the process capability of the tensile tests of the improved plastic cord..
QUESTION 2
Control charts for X and σ are to be established on the Brinell hardness of hardened tool steel in kilograms per square millimeter. Data
for subgroup sizes of 8 are shown below:-
SUBGROUP
NUMBER X σ SUBGROUP
NUMBER X σ
1 540 26 14 551 24 2 534 23 15 522 29
2 545 24 16 579 26 4 561 27 17 549 28 5 576 25 18 508 23 6 523 50 19 569 22 7 571 29 20 574 28 8 547 29 21 563 33 9 584 23 22 561 23 10 552 24 23 548 25 11 541 28 24 556 27
12 545 25 25 553 23 13 546 26
i. Determine the trial central line and control limits for the X and σ chart.
ii. Sketch the X and σ chart.
iii. Assume that the out-of-control points have assignable causes. Calculate the revised limits and central line. iv. Also calculate the process capability of the case-hardening process.
