Presentation Transcript

1. Managing Quality

   Chapter 5
2. Chapter Objectives Be able to: Discuss the various definitions and dimensions of quality and why quality is important to operations and supply chains. Describe the different costs of quality, including internal and external failure, appraisal, and prevention costs. Describe what TQM is, along with its seven core principles. Calculate process capability ratios and indices and set up control charts for monitoring continuous variables and attributes. Describe the key issues associated with acceptance sampling, as well as the use of OC curves. Distinguish between Taguchi’s quality loss function and the traditional view of quality.
3. 1. Define Quality.
4. Quality Defined Quality – The characteristics of a product or service that bear on its ability to satisfy stated or implied needs; a product or service that is free of deficiencies. Value perspective – A quality perspective that holds that quality must be judged, in part, by how well the characteristics of a particular product or service align with the needs of a specific user. Conformance perspective – A quality perspective focused on whether or not a product was made or a service was performed as intended.
5. Quality . . . What do we mean??? Quality is defined by the customer. Quality has a key role in customer perception of value. Quality= Conformance to customer specifications and expectations.
6. 2. What are the various dimensions of product quality?.
7. Dimensions of Product Quality* Performance What are the desirable characteristics of the product? Features What additional characteristics of the product are possible? Reliability Is the product dependable? Does it accomplish what it promises? Durability How long will the product last?
8. Dimensions of Product Quality* Serviceability Can the product be easily and inexpensively repaired? Aesthetics Does the product satisfy subjective requirements? Response Is the interaction between the customer and the product provider pleasant and appropriate? Reputation What does information on past performance say about the company?
9. 3. What are the dimensions of service quality?.
10. Dimensions of Service Quality Reliability Does the business keep its promises? Responsiveness Does it promptly respond to the needs of its customers? Assurance Can the employees generate customer trust and confidence?
11. Dimensions of Service Quality Empathy Are employees approachable and sensitive to individual customers? Tangibles Do the physical facilities, equipment, and written materials show care and attention?
12. 4. What are the eight dimensions of product and service quality?.
13. Eight Dimensions of Quality Performance Features Reliability Durability Conformance Aesthetics Serviceability Perceived Quality
14. Quality Dimension Examples Table 5.1
15. Dimensions of Product and Service Quality
16. 5. Define Cost of Quality (COQ).
17. Cost of Quality All of the costs associated with maintaining the quality of goods and services. Those costs are reduced as failures are moved closer to the firm and ultimately prevented.
18. 6. What are the dimensions of the Cost of Quality (COQ)?
19. Cost of Quality (COQ) Dimensions Prevention costs – Costs an organization incurs to actually prevent defects from occurring to begin with. Appraisal costs – Costs a company incurs for assessing its quality levels. Internal failure costs – Costs caused by defects that occur prior to delivery to the customer. External failure costs – Costs incurred by defects that are not detected until a product or service reaches the customer.
20. Total Cost of QualityTraditional View Figure 5.2
21. Total Cost of QualityZero Defects View Figure 5.3
22. 7. Define Total Quality Management (TQM).
23. Total Quality Management Total Quality Management - A managerial approach in which an organization is managed so that it excels in all quality dimensions that are important to customers.
24. 8. What are the components of TQM?
25. Total Quality Management Customer focus Internal Customer External Customer Leadership involvement Continuous improvement Employee empowerment Quality assurance Strategic partnerships Strategic quality plan
26. Total Quality Management Customer focus Each employee has a customer whether internal or external to the company. Leadership involvement Must be ‘top’ down, throughout the company. If not, major cause of TQM failures. Continuous improvement There is always room for improvement.
27. Total Quality Management Employee empowerment Giving employees the responsibility for managing quality. Quality assurance Quality Function Deployment (QFD) discussed in Chapter 15 Statistical quality control (SQC), also called statistical process control (SPC)
28. Total Quality Management Supplier Partnerships The commitment between firms and supply chain partners must be the same. Strategic Quality Plan Sets a broad set of objectives. Should establish measurable goals for the short-term.
29. 9. What are the steps in the TQM process?
30. Steps in the TQM Process TQM’ssupportiveapproaches 3 PrinciplesOf Quality
31. Total Quality Management’s Impact on Profitability Insert exhibit 6.9 (Impact on profitability)
32. 10. Define Statistical Process Control (SPC).
33. Statistical Process Control (SPC) SPC provides a preventing approach to managing quality by monitoring processes in a way that identifies potential problems before defects are even created.
34. Controlling Process Variability Common cause variability versus assignable cause variability Common cause variability comes from random fluctuation inherent to the process. Assignable cause variability is avoidable and not part of the process. SPC takes advantage of our knowledge about the standardized distribution of these measures. Process Control Identifies potential problems before defects are created by watching the process unfold It uses X-bar Charts, R-Charts, P-charts, and C-charts
35. Answers the Question:Can the process provide acceptable quality consistently? Process Capability
36. Control Charts Control Chart – A specialized run chart that helps an organization track changes in key measures over time. Continuous variable – A variable that can be measured along a continuous scale. Attribute – The presence or absence of a particular characteristic.
37. Control Charts X chart - A specific type of control chart for a continuous variable that is used to track the average value for future samples. R chart – A specific type of control chart for a continuous variable that is used to track how much the individual observations within each sample vary.
38. Continuous Variable Measurements
39. 11. What is the formula for capability index (Cp)?
40. Process Capability Ratio (Cp) Process Capability Ratio (Cp) – Measures whether or not a process is potentially capable of meeting certain quality standards Cp = Upper Tolerance Limit – Lower Tolerance Limit 6σ Where σ is the estimated standard deviation for the individual observations
41. Normal Distribution Figure 5.4
42. Process Capability Values Figure 5.5
43. Six Sigma Quality To achieve Six Sigma quality, the variability of a process must be reduced to the point that the process capability ratio is greater than or equal to 2.
44. Six Sigma Quality Figure 5.6
45. 12. What is the formula for Six Sigma Quality level?
46. Six Sigma Quality level Process Capability Ratio (Cp) – Measures whether or not a process is potentially capable of meeting certain quality standards Cp = Upper Tolerance Limit – Lower ToleranceLimit >= 2 6σ Where σ is the estimated standard deviation for the individual observations
47. 13. What are the formulae for X-bar and X-double bar?
48. Step 1 – Sampling the Process Observation
49. Step 2 – Calculate the Mean and Range for each sample
50. 14. What are the formulae for the upper and lower control limits for the X-bar chart?
51. Step 3 – Calculate control limits
52. Step 4 – Plot the Data Figure 5.8
53. 15. What is the formula for R-bar?
54. Step 2 – Calculate the Mean and Range for each sample
55. 16. What are the formulae for the upper and lower control limits for the R-bar chart?
56. Step 3 – Calculate control limits