Six Sigma Continuous Improvement

Transcription

1 Chapter 4 Six Sigma Continuous Improvement The signifi cant problems we face cannot be solved at the same level of thinking we were at when we created them. Albert Einstein 4.1 SIX SIGMA CONTINUOUS IMPROVEMENT PRINCIPLES Advancement to near perfection (maximum profitability) is virtually impossible without integration of proper engineering design, material, process, and control strategies in other words, achieving higher standard deviations in existing and future production processes. Six Sigma tools uncover the unseen root causes of potential problems and attack them to eliminate defect opportunities. This means that Six Sigma takes the necessary measurements at the early stages of product or process development before the problem occurs. Alternatively, it will focus on the processes indicating that their sigma level is either too low and cannot improve or a high sigma level (5 or more), which is too challenging to improve. One should keep in mind that the cost of redesign or correcting aftermath problems is extremely high and costly. (See Chapter 8 for more details.) Six Sigma can be achieved only with cross-functional groups or joint efforts throughout the organization with great intensity that is, if it is required by corporate culture and deployed firmly. Indeed, Six Sigma has to be applied from raw material all the way to the finished product and the shipping department. Essentials of Lean Six Sigma Copyright 2006 by Academic Press, Inc. All rights of reproduction in any form reserved. 43 ch004-p indd 43 4/19/2006 5:45:40 PM

2 44 Six Sigma Continuous Improvement Six-Sigma Performance Process Management Customer Driven Statistical Analysis Higher Profits Increased Value Reduced Variation Figure 4.1 Six Sigma breakthrough performance model. The performance of this is shown in Figure 4.1, the Six Sigma breakthrough model, with three main objectives: higher profit, increased value, and reduced variation. Six Sigma science of continuous improvement concentrates on two processes that each include three steps: Process Characterization 1. Define project and process measurement (diagnosis) 2. Evaluate existing sigma (capability study) 3. Analyze process data Process Optimization/Simulation 4. Improve and optimize process 5. Evaluate new sigma (capability study) 6. Control and maintain the process Or the above steps can be summarized in DMAIC (define/measure [diagnosis], analyze, improve [optimize], control). 4.2 SIX SIGMA SYSTEMS Six Sigma systems include the following concepts: 1. The fastest rate of improvement in customer satisfaction, cost, quality, process speed, and invested capital. 2. A business improvement and growth system, which leads to a new level of performance. ch004-p indd 44 4/19/2006 5:45:40 PM

3 Six Sigma Continuous Improvement 45 Six Sigma Approach Process Characterization (Existing Process) Define Project Measure Process Estimate Existing Sigma Analyze Data Process Optimization (New Process) Improve Process Estimate New Sigma Process Control And Maintain Figure 4.2 Representation of Six Sigma define and measure, analyze, improve or optimize, and control (DMAIC) levels. 3. A systematic data-driven approach to analyzing the root cause of manufacturing, as well as business problems/processes and dramatically improving them. 4. Improved decisions based on knowledge and data. 5. A financial results-driven system ($ performance paramount). 6. A project-driven system based on customer needs. 7. A system applicable to all parts of a business. 8. Aimed at the problem where the solution is not known. 9. A system with proven performance. 10. Improve customer satisfaction and supplier relationships. 11. Expand knowledge of product and processes. 12. Develop a common set of tools and improvement techniques. Figure 4.2 illustrates the graphical representation of Six Sigma improvement steps. 4.3 SIX SIGMA IMPROVEMENT AND TRAINING MODELS One may obtain Six Sigma training certification by completing the improvement models for Green Belt and Black Belt. These trainings are available through academic institutions, as well as quality societies or other certified organizations. ch004-p indd 45 4/19/2006 5:45:40 PM

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5 Goal Sub-Goal Sub-Goal Sub-Goal Chan Work ge d Environmen Production Con Systemtro In = 2 Out= 2 In = 1 Out =3 In = 2 Out = 2 Organizationa Structure In = 3 Out= 1 Communication Workplace Motiv ation Con flic In = 1 Out= 4 In = 4 Out= 1 Cust ome Expectation Satisfaction Six Sigma Continuous Improvement 47 Objective Tools and Techniques THEME THEME THEME Idea Idea Idea Idea Idea Idea Idea Idea Define Identify Business Drivers Select Customer Critical Processes Define Projects Develop Implementation Plan Affinity Diagram/ Interrelation Diagram Quality Function Deployment SIPOC Process Map Project Charter Idea Idea Idea Idea Idea Idea Idea Idea Idea Idea Idea Idea Idea Hows QFD Whats Relationship Driver (Cause) S I P O C Outcome (Effect) Matri x Day1 Day 2 Day 3 Day Measure Develop Key Process Measures Collect and Analyze Data Identify the Vital Few that Have the Greatest Impact Estimate Process Capability Measurement Systems Analysis Data Collection Plan Check/Data Sheet Pareto Chart Gage R&R Histogram Process Capability Paint Test Perf Cp & CpK AB1 AB2 AB3 AB4 AB5 Machines Methods Wr ong S elect ion Analyze Understand Cause and Effects Create Multi-vari Analysis Determine Variance Components Assess Correlation Cause and Effect Diagram Multi-vari Charts Scatter Diagram Availabilit y Maintenance Out dat ed P r act ices Calibr at ion Training Har dness Available Resour ces Surface Finish Manpower Materials Variation/ Opportunity X Variable Y Variable X High Start Task Task Improve Develop and Evaluate Solutions Implement Variation Reduction Standardize Process Assess Risk Factors Design of Experiments Deployment Flowchart Tree Diagram FMEA Factor B Factor C Low Low Factor A High Task N Decision Y Task Finish Task Finish Failure Mode Effects Analysis Risk Prioritization Number Process Control Plan Control Implement Process Control Implement Control Charts for Key Variables Mistake Proof Processes Evaluate Results Process Control Plan Control/Precontrol Chart Poka-Yoke Pareto Chart (ongoing) Process Capability (ongoing) Customer Front Desk Process Orders Pizza Description Process Cust omer Job Process Flowchart Time Cook Deliver y 00:00 01:30 Takes Order P1 Each 04:30 Passes to Cook 10 : 15 Insertion Loads Pizza Cooks P izza P3 11: 3 0 no Pay for Pizza Don e? Q1 35:30 Q2 yes Deliver Misc CHE CK I NG Indicators When Responsibilit y Frequen Who to AND Specs/ Con t r ocheckin g Check Checks Con cy t in g. Targets Limit s Item Plan Ticket on Time Each Cook oven stamp Printing or Each der Fron t or der Cook P3 11 minut es Cook Into Oven 30 seconds Rev# Dat 2/96 e by UCL x LCL No Mistakes Figure 4.4 Six Sigma Black Belt improvement model. ch004-p indd 47 4/20/ :36:59 AM

6 48 Six Sigma Continuous Improvement On the other hand, you can apply all the procedures and guidelines of this book to any desired projects. Once you have knowledge and experience, you can participate in certified examinations through a quality organization. The training models for the Green Belt and Black Belt are cited in Figures 4.3 and 4.4. The details of these models are discussed in Chapter 8. ch004-p indd 48 4/19/2006 5:45:41 PM