Teuvo Suntio. Quality Development Tools. Professor of Power Electronics at University of Oulu. Electronic System Design A TS Rev. 1.

Transcription

1 * * * Quality Development Tools Teuvo Suntio Professor of Power Electronics at University of Oulu Slide 1/25

2 Six Sigma: [1] S. G. Shina, Six Sigma for Electronics Design and Manufacturing, McGraw-Hill, 2002, pp [2] R. V. White, An introduction to Six Sigma with a design example, in Proc. IEEE APEC 92, 1992, pp [3] J. Antony, R. Banuelas, Design for Six Sigma, IEE Manufacturing Engineer, vol. 81, issue 1, Feb. 2002, pp [4] P. A. Tobias, A Six Sigma program implementation, in Proc. IEEE Custom Integrated Circuits Conference, 1991, pp [5] B. Mitchell, The Six Sigma appeal, IEEE Engineering Management Journal, vol. 2, issue 1, Feb. 1992, pp [6] P. Catherwood, What s different about Six Sigma?, IEE Manufacturing Engineer, vol. 81, issue 4, Aug. 2002, pp [7] W. Smith, Making war on defects, IEEE Spectrum, vol. 30, issue 9, September 1993, pp Slide 2/25

3 Defects in a large population of products are typically distributed according to the standard normal distribution characterized by mean or nominal value m and standard deviation s. Generally the manufacturing process width is specified as m ±3s. It was earlier common that the product specification width (i.e., lower limit (LSL) and upper limit (USL)) was set also to the same value as the process width. This approach yields 2700 defects/ 10 6 manufactured parts (i.e., 2700 ppm). This is actually known as Three Sigma approach. In late 80 s Motorola took a more tighter approach known as Six Sigma approach, where the specification width (i.e., LSL and USL) was set to m ±6s yielding only defects/ 10 6 manufactured parts (i.e., ppm) ppm 1350 ppm 1350 ppm ppm µ ±3σ LSL ±6σ USL Slide 3/25

4 The manufacturing process cannot, in practice, keep the mean value exactly in the middle of the specification limits or the quality of design is such that this may not take place. Therefore, a variation of ± 1.5 s from the mean value is expected. This means that the limits are shifted from m ±6s to m-/+7.5s and to m +/- 4.5s. The highest or lowest limit corresponding to m ±7.5s gives negligible defects, but the other limit corresponding to m ± 4.5s gives 3.4 defects/ 10 6 manufactured parts (i.e., 3.4 ppm). 0.0 ppm 7.5σ 4.5σ 3.4 ppm µ + 1.5σ LSL ±6σ USL Slide 4/25

5 In Statistical Process Control (SPC), the process quality is defined as process quality index C p defined as the ratio between the specification width and the process capability or width, i.e., C p USL LSL = 6σ ( = 2 for Six Sigma) As defined earlier, the shift of the process mean value from the centered mean also affects the process capability. This effect is introduced as C pk index. The capability constant k is defined as k = process shift ( USL LSL)/2 and C pk as C = C (1 k) pk p C pk can be also defined as C pk USL process average process average LSL = min(, ) 3σ 3σ Slide 5/25

6 Quality Function Deployment (QFD): [1] S. G. Shina, Six Sigma for Electronics Design and Manufacturing, McGraw-Hill, 2002, pp [2] Yoji Akao, Quality Function Deployment Integrating Customer Requirements into Product Design, Productivity Press, 1990, pp [3] P. A. Davis, QFD A structured approach to understanding the voice of customer, in Proc. IEEE APEC 95, 1995, pp [4] C. Beskow, J. Johansson, M. Norell, Implementation of QFD: Identifying success factors, in Proc. IEEE IEMC 98, 1998, pp [5] V. Bouchereau, H. Rowlands, Analytical approach to QFD, IEE Manufacturing Engineer, vol. 78, issue 6, Dec. 1999, pp [6] J.J. Cristiano, J. K. Liker, C. C. White, Key factors in the successful application of quality function deployment (QFD), IEEE Trans. On Engineering Management, vol. 48, no. 1, Feb. 2001, pp [7] K. Otto, K. Wood, Product Design Techniques in Reverse Engineering and New Product Development, Prentice Hall Inc., 2001, pp Slide 6/25

7 Success in business may be most often related in a way or another to customer satisfaction. Therefore, the voice of customer must be listen. Customer satisfaction as a concept is quite vague in a way but does not merely mean that all the customer wishes have to be obeyed and implemented in a product. Japanese Dr. Kano has created a model known as Kano model ( where quality and customer satisfaction are divided into basic, expected and exciting level as shown in the underlying figure. The customer will be dissatisfied if the quality of the product does not meet his/her expectation. The levels are, however, highly variable. The exciting level of today would be expected level of tomorrow. Satisfaction + Exciting Expected - Basic + Quality - Slide 7/25

8 Quality Function Deployment (QFD) is a quality tool developed by Japanese Dr. Akao together with Drs. Mizuno and Furukawa in early 70s to formalize the implementation of quality assurance in product design. The ideas and methods of QFD are presented as definition, correlation and relationship matrices in the form of House-of-Quality (HoQ). The name comes from the shape of the presentation as shown in the attached figures. The matrix presentation composes of several rooms for specific purposes which depend on the product development phases in question. The relationships are typically defined as strong, medium and weak as well as correlations positive and negative. Room 1 WHATs Room 2 WHYs What Customer Want Room 5 correlation matrix HOWs vs. HOWs Room 3 HOWs Room 4 realtionship matrix WHATs vs. HOWs Room 7 importance weighting Room 8 target values Room 9 technical competetive evaluation (How), design requirements I Product Planning Important characteristics Room 6 customer evaluation Slide 8/25

9 The deployment means that the HOWs of the previous HOQ become the WHATs of the next HOQ as shown in the underlying figure. (How), design requirements Part characteristics Manufcaturing requirements Product requirements What Customer Want I Product Planning Important characteristics Design requirements II Product Design Important characteristics Part characteristics III Process Planning Important characteristics Manufacturing requirements IV Production Important characteristics The QFD technique is not easy to adopt, and requires some effort to learn the associated tricks and techniques. One example is provided in a next page concerning SMT (Surface Mount Technology) solder process, which may somewhat illustrate the method. Slide 9/25

10 Strong relation ship = 5 Medium relation ship = 3 Weak relation ship = 1 Customer Needs Primary Process Characteristics Secondary No solder shorts S c r e e n P l a c e L o a d R e f l o w V i s i o n S u p p l y Im po rta nc e 9 Worse Competetive Analysis Better No opens Quality No loading errors Paste height Low downtime Delivery Consistent output Weighted Requirements Target Specification Technical Analysis Slide 10/25

11 Capability Maturity Model Integration (CMMI): [1] D. M. Ahern, A. Clouse, R. Turner, CMMI Distilled: Practical Introduction to Integrated Process Improvement, Addison-Wesley, 2001, pp.306. [2] Carnegie Mellon University, Capability Maturity Model Integration (CMMI) Version 1.1; CMMI for Systems Engineering, Software Engineering, Integrated Product and Process Development, and Supplier Sourcing (CMMI-SE/SW/IPPD/SS V1.1), March 2002, Slide 11/25

12 The Capability Maturity Model (CMM) was originally developed in late 80 s to master software projects by the Software Engineering Institute (SEI) at the Carnegie Mellon University. The fully developed model (version 1.1) was released in The goal of CMM is to provide a framework for a method to work having close ties to the theories and practices of quality management. The CMM concepts have been expanded to other discipline in addition with the software in product development. The new model is known Capability Maturity Model Integration or CMMI. It has been developed based on the original CMM in co-operation with industry and US Department of Defense. The corresponding model descriptions can be down loaded free of charge from The model is widely in use in different companies. Models are developed by far for System Engineering, Integrated Product and Process Development and Supplier Sourcing [2]. One fundamental issue is whether to use continuous or staged model. An organization may choose to approach process improvement from the perspective of either process area capability or organizational maturity in each area individually. This approach is supported in a continuous representation, with its use of the key term capability. Slide 12/25

13 An organizational maturity perspective emphasizes sets of process areas that are intended to define proven stages of process maturity across an organization. This approach is employed in a staged representation, with its use of the key term maturity. The staged representation is briefly introduced. Reference [2] provides more detailed presentation. The model composes of five maturity levels (ML) (i.e., initial, managed, defined, quantitatively managed and optimizing) according to which the organization proceeds stage by stage : Maturity Level 1: Initial Processes are usually ad hoc and chaotic. The organization usually does not provide a stable environment. Success in these organizations depends on the competence and heroics of the people in organization and not on the use of proven processes. In spite of this ad hoc, chaotic environment, maturity level 1 organizations often produce products and services that work; however, they frequently exceed the budget and schedule of their projects. Slide 13/25

14 Maturity Level 2: Managed An organization has achieved all the specific and generic goals of the process areas assigned to maturity level 2. In other words, the projects organization have ensured that requirements are managed and that the processes are planned, performed and managed according to their documented plans. At maturity level 2, requirements, processes, work products, and services are managed. the status of the work products and the delivery of services are visible to management at defined points ( at major milestones and at the completion of major tasks). Commitments are established among relevant stakeholders and are revised as needed. work products are reviewed with stakeholder and are controlled. the work products and services satisfy their specified requirements, standards, and objectives. Slide 14/25

15 Maturity Level 3: Defined An organization has achieved all the specific and generic goals of the process areas assigned to maturity levels 2 and 3. Processes are well characterized and understood, and are described in standards, procedures, tools, and methods. The organization s sets of standard processes, which is the basis for maturity level 3, is established and improved over time. These standard processes are used to establish consistency across the organization. Projects establish their defined processes by tailoring the organization s set of standard processes according to tailoring guidelines. The organization s management establishes process objectives based on the organization s set of standard processes and ensures that these objectives are appropriately addressed. Slide 15/25

16 Maturity Level 4: Quantitatively Managed An organization has achieved all the specific goals of the process areas assigned to maturity levels 2, 3 and 4 and the generic goals assigned to maturity levels 2 and 3. Subprocesses are selected that significantly contribute to overall process performance. These subprocesses are controlled using statistical and other quantitative techniques. Quantitative objectives for quality and process performance are established and used as criteria in managing processes. quantitative objectives are based on the needs of the customer, end users, organizations, and process implementers. Quality and process performance is understood in statistical terms and are managed throughout the life of the process. For these processes, detailed measures of process performance are collected and statistically analyzed. Special causes of process variation are identified and, where appropriate, their causes are corrected to prevent future occurrence. Quality and process performance measures are incorporated into the organization s measurement repository to support fact-based decision making. Slide 16/25

17 Maturity Level 5: Optimizing An organization has achieved all the specific goals of the process areas assigned to maturity levels 2, 3, 4 and 5 and the generic goals assigned to maturity levels 2 and 3. Processes are continually improved based on a quantitative understanding of the common causes of variation inherent in processes. Maturity level 5 focuses on continually improving process performance through both incremental and innovative technological improvements. Quantitative process-improvement objectives for the organization are established, continually revised to reflect changing business objectives, and used as criteria in managing process improvement. The effects of deployed process improvements are measured and evaluated against the quantitative process-improvement objectives. both the defined processes and organization s set of standard processes are targets of measurable improvement activities. Slide 17/25

18 Several process areas may be identified in organization within process management, project management, engineering and support being at a specified maturity level as discussed earlier and depicted by the underlying figure. All the process area related generic and specific goals and practices are described in detail in the model documentation [2]. Maturity Le vels Process Area 1 Process Area 2 Process Area n Specific Goals Generic Goals Common Features Specific Practices Commitment to Perform Ability to Perform Directing Implementation Verifying Implementation Generic Practices Slide 18/25

19 Process management category includes five areas organizational process definition (OPD, ML3), organizational process focus (OPF, ML3), Organizational training (OT, ML3), organizational process performance (OPP, ML 4), and organizational innovation and deployment (OID, ML 5). In addition the areas are divided into basic and advanced areas. The basic areas are illustrated in the figure below and the advanced in the next slide. Senior management Organization s process needs and objectives Training for projects and support groups in standard process and assets Organization s business objectives OT Training needs OPF Resources and coordination OPD Standard process and other assets Standard process and other assets Project Management, Support, and Engineering process areas Process improvement proposals; participation in defining, assessing, and deploying processes Improvement information (e.g., lessons learned, data, artifacts) Slide 19/25

20 Organization Improvements Cost and benefit data from piloted improvements OID Senior management Quality and process performance objectives, measures, baselines, models Progress toward achieving business objectives OPP Quality and process performance objectives, measures, baselines, models Project Management, Support, and Engineering process areas Common measures Process performance and capability data Ability to develop and deploy process and supporting assets Basic set of Process Management process areas Slide 20/25

21 Project management category includes seven areas project planning (PP, ML2), project monitoring and control (PMC, ML2), supplier agreement management (SAM, ML2), integrated project management (IPM, ML3),risk management (RSKM, ML3), integrated teaming (IT, ML3), and quantitative project management (QPM, ML4). In addition the areas are divided into basic and advanced areas. The basic areas are illustrated in the figure below and the advanced areas in the next slide. Corrective action Replan PMC What to monitor Corrective action Status, issues, results of process and product evaluations; measures and analyses Status, issues, results of progress and milestone reviews Plans PP What to build What to do Commitments Engineering and Support process areas SAM Measurement needs Supplier agreement Supplier Product component requirements, technical issues, completed product components, acceptance reviews and tests Slide 21/25

22 Process Management process areas Configuration management, verification, and integration data ISM Process Performance objectives, baselines, models Organization s standard processes and supporting assets Monitoring data as part of supplier agreement Statistical Mgmt Data Lessons Learned, Planning and Performance Data Product architecture for structuring teams Quantitative objectives Subprocesses to statistically manage IPM for IPPD Project s defined process Engineering and Support process areas QPM Coordination and collaboration among project stakeholders Shared vision and integrated team structure for the project Coordination, commitments, issues to resolve Integrated team management for performing engineering processes Project performance data Integrated work environment and people practices Risk exposure due to unstable processes Identified risks IT Project s defined process RSKM Risk taxonomies & parameters Risk status Risk mitigation plans Corrective action Basic Project Management process areas Slide 22/25

23 Engineering category includes six areas requirements management (REQM, ML2), requirements development (RD, ML3), technical solution (TS, ML3), product integration (PI, ML3), verification (VER, ML3) and validation (VAL, ML3) as depicted in the figure below. REQM Requirements Product and product component requirements RD Alternative solutions Requirements TS Product components PI Product Customer Product components, work products, verification and validation reports VER Customer needs VAL Slide 23/25

24 Support category includes six areas configuration management (CM, ML2), product and process quality management (PPQA, ML2), measurement and analysis (MA, ML2), decision analysis and resolution (DAR, ML3), organizational environment for integration (OEI, ML3) and causal analysis and resolution (CAR, ML5). In addition the areas are divided into basic and advanced areas. The basic areas are illustrated in the figure below and the advanced areas in the next slide. MA Measurements, analyses All process areas Quality and noncompliance issues PPQA Information needs Processes and work products, standards and procedures Configuration items, change requests Baselines, audit reports CM Slide 24/25

25 Organization IPPD Infrastructure CAR Defects and other problems Process improvement proposals Ability to develop and deploy IPPD processes and supporting assets IPPD knowledge and skill needs OEI Integrated work environment and people practices Process Management process areas Project Management process areas All process areas Selected issues Formal evaluations More information on CMMI and related topics can be found from Refs. [1] and [2] as well as the specified internet address. DAR Slide 25/25