QC Tool

1. 7 QC TOOLS

5. Meaning of “Quality” P = Performance or result E = Expectations Q = P E

7. Cost Quality and Profit : Traditional thinking

8. Quality and Profit : Paradigm shift Cost

12. PROBLEM SOLVING PROCESS PROBLEM SOLVING PROCESS

23. CHECK SHEETS Component name : ABC Date of Production:22-Aug-03 Type of defects Check Sub-Total Scratch 3 Dent 7 Flow mark 11 Short Shot 2 Total 23

25. Histogram for distribution of Center Distance (mm) HISTOGRAM

26. HISTOGRAM A HISTORY OF PROCESS OUT PUT 0 2 4 8 10 12 14 16 6 Frequency 47 48 49 50 51 52 53 54 kg Distribution

29. PARETO ANALYSIS

31. The problem categories considered are : Man, Machine, Method, Materials, Equipments & Environmental. EFFECT MACHINE METHOD ENVIRONMENT MAN MATERIAL EQUIPMENT CAUSE n EFFECT (FISH BONE) DIAGRAM

33. SCATTER DIAGRAM (POSITIVE CORRELATION)

34. SCATTER DIAGRAM (NEGATIVE CORERLATION)

35. SCATTER DIAGRAM (NO CORERLATION)

37. DEFECT CONCENTRATION DIAGRAM Component name : XYZ Concentration diagram for Scratches produced ion 21-Aug-03 Total no of defective produced is 11 Nos Area of concern

40. Elements of Typical Control Chart Target Lower control line Upper warning line Lower warning line Upper control line Lower control line 1 2 3 4 5 Sample Number Sample Statistics

42. Zones for Mean Control Chart 1 2 3 4 5 6 7 Sample Number UCL Target LCL UWL LWL Zone - 3 Sample Mean Zone - 2 Zone - 3 Zone - 2 Zone - 1 Action Action Warning Warning Continue Continue Zone - 1

43. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 Sample Number Statistics UWL LCL Target LWL Point outside the Control limit

44. Control Chart Views Process in Real Time Time Intervals Range Mean LCLx Output of the process in real time Target Target UCLx UCLr

45. Change in Location of Process Mean 43 48 49 50 51 52 53 44 45 46 47 Process with mean at Target Process with mean at more than target Process with mean at less than target

46. Case When Process Mean is at Target 48 49 50 51 52 53 44 45 46 47 Target Process Mean Chances of getting a reading beyond U & L is almost nil 42 U L - 3 s +3 s U - L = 6 s 43

47. Case - Small Shift of the Process Mean 43 48 49 50 51 52 53 44 45 46 47 Target Process Mean Chances of getting a reading outside U is small Small shift in process 42 Shaded area shows the probability of getting a reading beyond U U L U-L = 6 s

48. Case - Large Shift of the Process Mean Process Mean 43 48 49 50 51 52 53 44 45 46 47 Target Chances of getting a reading outside U is large Large shift in process 42 Shaded area shows the probability of getting a reading beyond U U L U-L = 6 s

49. Change in Spread of Process 43 48 49 50 51 52 53 44 45 46 47 Larger spread due to special causes Spread due to common causes

52. Control Chart How to draw?

57. Establishing Control Chart

59. Typical Data Collection Sheet

62. Example - Data Collection

64. Example - Calculation of subgroup Mean & Range

65. Establishing Control Chart In our case Calculate Mean Range, R R = Sum of ranges of subgroups Total number of subgroups R = (7 + 5 +4 3 + 5 + 4 + 6 + 4 + 3 + 3 ) Total number of subgroups

76. Action and Warning Limits for Mean Control chart 1 2 3 4 5 6 7 Sample Number Mean UCLx LCLx UWLx LWLx Target

77. Action and Warning Limits for Mean Control Chart for Example 1 2 3 4 5 6 7 Sample Number Mean UCLx=52.5 LCLx= 47.5 UWLx=51.7 LWLx=48.3 Target=50

78. Constants for Range Control chart

82. Action and Warning Limits for Control Chart 1 2 3 4 5 6 7 Mean UCLx = 52.5 LCLx = 47.5 UCLr = 9.3 Range UWLr = 8 LWLr = 1.6 Target = 50 R = 4.4 Sample Number LWLx = 48.3 UWLx = 51.7

83. Flow Chart for Establishing Control Chart Decide subgroup size Record observations Find mean and range of each subgroup Start Calculate mean range, R

84. Is any sub-group mean or range out side the control limit ? Drop that Group Yes No Flow Chart for Establishing Control Chart UCLx = T + A2 x R LCLx = T - A2 x R UCLr = D4 x R LCLr = D3 x R

85. Select suitable scale for mean control chart and range control chart Draw Lines for Target, UCL, UWL, LCL & LWL for mean Mean range, UCL , UWL, LCL & LWL for range Stop Flow Chart for Establishing Control Chart

90. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 Sample Number Statistics UWL LCL LWL One point outside control limit

91. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 Sample Number Statistics UWL LCL LWL Two points out of three consecutive points between warning limit and corresponding control limit

92. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 Sample Number Statistics UWL LCL LWL Two consecutive points between warning limit and corresponding control limit

93. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 UWL LCL LWL Seven consecutive points on one side of the centre line Sample Number Statistics

94. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 Sample Number Statistics UWL LCL LWL Seven consecutive points having upward trend

95. Interpreting Control Chart UCL 1 2 3 4 5 6 7 8 Sample Number Statistics UWL LCL LWL Seven consecutive points having downward trend