品质管理精华理论Supplier_Summit.pptVIP

1 SQE Business Process Improvement 1. Understand the difference between Inspection and Variation Reduction (SPC and Process Capability) 2. Review New Process Capability 10-Steps and Scorecard 3. What help do you need from Dell? Questions and Answers Objectives 2 Global BPI Process Capability Summit Kirk Chi Dell Inc. WWP BPI Business Champion Dell Black Belt ASQ Certified Six Sigma Black Belt ASQ Certified Quality Engineer 7/05/04 3 SQE Business Process Improvement Traditional Economic Model of Quality of Conformance Total cost Cost due to nonconformance Cost of quality assurance “optimal level” of quality 100% Quality improvement based on Inspection 4 SQE Business Process Improvement Modern Economic Model of Quality of Conformance Total cost Cost due to nonconformance Cost of quality assurance 100% Quality improvement based on Variation Reduction (SPC/Process Capability) 5 SQE Business Process Improvement Non-Value Added operations result in: (1) Higher procurement cost of products (2) Higher probability of defects Improve the Process To Reduce Non-Value-Added Operations Dell VLRR/PID/CND Hidden Costs 6 SQE Business Process Improvement What is the difference between quality control based on Inspection and Variation Reduction? Inspection refers to the manufacturing operations based on Attribute Data (Pass/Fail). Current manufacturing operations are focused mainly on Pass/Fail inspections. Much of variable data is measured, but the data is converted to attribute data for Pass/Fail inspection. 7 SQE Business Process Improvement If you inspect 100%, will your customer experience no failure? If you inspect 100%, and inspect again 100%, and inspect again 100%, will your customer experience no failure? Can you and Dell achieve the reduction of FIR (and VFIR) based on inspection quality control? 8 SQE Business Process Improvement We will work together to understand the following points: Even if you inspect 100%, your customer will still experience failures Inspection does not detect the process and product mean shift 100% Inspection does not reduce the variation in your process (and product) 9 SQE Business Process Improvement Traditional Inspection View Lower Spec Upper Specno loss nominal tolerance Traditional view: There is no failure as long as a parameter is within specification 10 SQE Business Process Improvement New View (Taguchi Loss Function) nominal tolerance Failure rate, $ Lower Spec Upper Spec no loss New View: Products still fail in time even if a parameter is within spec. The probability of failure increases as the parameter shifts away from the mean 11 SQE Business Process Improvement nominal tolerance Failure rate, $ Lower Spec Upper Spec no loss Where do we want to go? 12 SQE Business Process Improvement Critical Process Parameters ( x ) Product Attribute ( y(x) ) Metric (Y) VLRR Sigma Level (Drive for 5) PA PB 1 2 3 YieldCpkMetric What Measured Metric (Y) Sigma Level (Drive for 5) VIFIR + 90 D VFIR Key Message: Only the reduction of process and product parameter variations will lead to the reduction of VFIR High Cost of Quality Lowest Cost of Quality Approach to Process Capability Identifying Cause and Effect 13 SQE Business Process Improvement What is Process Capability? Process Capability is the “Voice of Process” to the “Voice of Customer”. Process Capability study provides valuable insight on how well an existing process is performing with regards to customer requirements (specifications) what needs to be done to improve performance Capability studies enable manufacturers to improve productivity, reduce costs, and enhance their strategic advantage over competitors. 14 SQE Business Process Improvement Process Stability Before Capability Control of a process must be achieved first, before any attempt is made to measure capability or estimate the percentage of nonconforming product. When a process is stable, it is repeatable, well-defined, and predictable. 15 SQE Business Process Improvement You can predict the outcome only if the process is stable time PREDICTABLE ? UNPREDECTIBLE 16 Global BPI Process Stability: Statistical Process Control 17 SQE Business Process Improvement Statistical Process Control (SPC) A process output is considered stable when it consists of only common-cause variation. 18 SQE Business Process Improvement Sources of Variation in Production Processes Materials Tools OperatorsMethods Measurement Instruments Human Inspection Performance EnvironmentMachines INPUTSPROCESSOUTPUTS 19 SQE Business Process Improvement Common Causes Special Causes 20 SQE Business Process Improvement Two Fundamental Management Mistakes Treating as a special cause any fault, complaint, mistake, breakdown, accident or shortage when it actually is due to common causes Attributing to common causes any fault, complaint, mistake, breakdown, accident or shortage when it actually is due to a special cause 21 SQE Business Process Improvement Control Chart Focuses attention on detecting and monitoring process variation over time Distinguishes special from common causes of variation Serves as a tool for on-going control Provides a common language for discussion process performance * * * * * * * 22 SQE Business Process Improvement Commonly Used Control Charts Variables data x-bar and R-charts x-bar and s-charts Charts for individuals (x-charts) Attribute data For “defectives” (p-chart, np-chart) For “defects” (c-chart, u-chart) 23 SQE Business Process Improvement Statistical Process Control (SPC) A methodology for monitoring a process to identify special causes of variation and signal the need to take corrective action when appropriate 24 SQE Business Process Improvement Shift in Process Average 25 SQE Business Process Improvement Identifying Potential Shifts 26 SQE Business Process Improvement Cycles 27 SQE Business Process Improvement Trend 28 Global BPI Quantitative Comparison of Traditional Inspection vs. Control Chart 29 SQE Business Process Improvement Review of Variable-Data Control Charts +3-3 +1 +2 -1 -2 +/- 1 = 68% +/- 2 = 95% +/- 3 = 99.73% Individual measurement distribution 30 SQE Business Process Improvement SPC Control Limits x-barx-bar+3X-bar x-bar = / UCL (Upper Control Limit) = X(double bar) + 3X-bar LCL (Lower Control Limit) = X(double bar) - 3X-bar Sample mean distribution 31 SQE Business Process Improvement Distribution of X vs. Distribution of Sample Means (X-bar) +3-3 x-barx-bar+3X-bar x-bar = / Individual measurement distribution Sample mean distribution 32 SQE Business Process Improvement There is no relationship. Spec limits are determined by engineering based on customer requirements Control limits are determined by the common- cause variation in the process Spec limits are typically wider than control limits Spec Limit vs. Control Limit 33 SQE Business Process Improvement +3-3 Control Chart: Example: Control chart is monitored by UCL and LCL. (Note: USL and UCL do not have any relation.) USL LSL x-barx-bar+3X-bar UCLLCL *If =2 for Inspection of individual parts, of subgroup size of 4 samples = 1. 34 SQE Business Process Improvement Why Control Charts Are Better Than Inspection? +3-3 Inspection: Example: One part is checked each hour. One part is checked every 20. Part passes the inspection if the part measurement is within spec. USL LSL *Assumption: spec limit lis +/-3 sigma. 35 SQE Business Process Improvement +3-3 What happens to Inspection if process mean shifts 3 sigma? USL LSL Anything above USL are rejected. 50% Because half of the pieces are still within spec, there is 50% chance of selecting such a part and mistakenly deciding to continue running this modified process. 36 SQE Business Process Improvement What happens to Control Chart if process mean shifts 3sigma? x-bar UCLLCL *If =2 for Inspection of individual parts, of subgroup size of 4 samples = 1. 99.865% Only 0.135% of the subgroup averages would fall within the control limits. Conversely, 99.865% will be above UCL. There is almost 100% chance this shift in the process mean will be detected. +3 shift 37 Global BPI Power of X-bar Chart to Detect Process Changes 38 SQE Business Process Improvement Producers Risk (Alpha error): Rejecting a good part Alpha error measure the probability of rejecting good parts in the factory. Consumers Risk (Beta error): Shipping bad parts Beta error measures the probability of shipping bad parts to customers 39 SQE Business Process Improvement (1-) Probability of detecting a process shift is higher with larger n, i.e. Beta error (consumers risk) decreases as n increases. 40 Global BPI Process Capability 41 SQE Business Process Improvement Process Capability is defined as the ability of a process to satisfy customer expectations. Because the specification limits are assumed to reflect customer desires, capability measures are said to relate the “Voice of the Process” to the “Voice of the Customer” 42 SQE Business Process Improvement Process Capability specificationspecification specificationspecification natural variationnatural variation (a)(b) natural variationnatural variation (c)(d) 43 SQE Business Process Improvement Process Capability Index Cp = USL - LSL 6s Cpl, Cpu USL - m 3s Cpl = m - LSL 3s Cpk = min Cpu = 44 SQE Business Process Improvement Process Capability Process Capability Index, Cp Cp 1.33, Capable Cp = 1.00 1.33, Capable with tight control Cp 1 in 2 9Very high 1 in 3 8High1 in 8 7Moderat ely high 1 in 20 6Medium1 in 80 5Low1 in 400 4Slight1 in 2K 3Very slight 1 in 15K 2Remote1 in 150K 1Impossib le 1 in 1.5M Ra nk Probabili ty Defect Shipped 10Never1 in 10 9Very remote 1 in 20 8Remote1 in 50 7Very low1 in 100 6Low1 in 200 5Moderat e 1 in 500 4Moderat ely high 1 in 1K 3High1 in 2K 2Very high 1 in 5K 1Certain1 in 10K 82 SQE Business Process Improvement Measure: Assign Ratings and Calculate Risk Severity is related to failure mode and effects Severity can be assign a rating based on either the failure mode, the worst effect, or each effect separately Just make sure to stay consistent throughout the entire FMEA analysis Process Function Failure Mode Effects of Failure SEV Causes of Failure OCC S*O Current Controls DET RPN Actions Install FanFan not seated properly Fan fails test Extra handling Noise and dispatch 7 Contamination321None10210 Poor training535Build certification9315 Improper installation 535WI, BOM7245 No tactile feedback 642None10420 83 SQE Business Process Improvement Measures of Risk Process Function Failure Mode Effects of Failure SEV Causes of Failure OCC S*O Current Controls DET RPN Actions Install FanFan not seated properly Fan fails test Extra handling Noise and dispatch 7 Contamination321None10210 Poor training535Build certification9315 Improper installation 535WI, BOM7245 No tactile feedback 642None10420 Measure of RiskExamplesComments SeverityA fire An injuryAddress high severity immediately S*O, Severity*Occurrence Lots of fires Multiple injuries Optional; especially useful for Design Risk Priority Number (RPN) Lots of fires and we cant find them What injuries? Traditional FMEA measure of risk Approaches to Prioritize Risk Address severity ratings of 9 or 10 immediately Focus on highest RPN first Use Pareto method Can be applied to both S*O and RPN Use risk thresholds RPNs greater than 50 Define categories of action: critical / high / minor 84 SQE Business Process Improvement Manufacturing Process Capability NPI Product Capability Manufacturing Process Identify Product Critical Parameters during Design and Qualification phases. Implement SPC and assess Cp + Cpk in NPI phase. Use the info to make Mass Product Decision. Identify Process Critical Parameters that are associated with supplier yield failures, Dell line failures, and Dell field failures during mass production. Implement SPC and Capability Analysis on both Product and Process critical parameters NPI Product Capability Identifying both Product and Process Critical Characteristics 85 SQE Business Process Improvement Qualification Qualification is done with small sample size NPI and Mass Production Sources of Variation are added: New sub tier suppliers are added New manufacturing lines are added New tools are added More operators are added ECNs and PCNs are generated Identify critical product parameters. Conduct Statistical analysis to determine if product parameters are stable. Does Design support Manufacturability? Continue to monitor Product Capability Identify critical process parameters. Improve Process Capability Improve Throughput Yields From New Product Qualification to Mass Production 86 SQE Business Process Improvement Example: MONDEO CRITICAL VARIABLES Characteristic SpecificationEvaluation / Measurement Sampling Plan Control Method Process Capability Comments No Electrical Functionality Product 1 Main Oscillator Frequency Motherboard Assembly 14.318MHZ +/- 50ppM Frequency Counter5/100 PCBAXbar & R*Refer to Note 1Lessons learned 2 VDDQ (2.6V) measurements Motherboard Assembly 2.6V +/-5%DVM or ICT5/100 PCBAXbar & R*Refer to Note 1 Will indicate power supply and DC to DC issues 3 Functional Test Total Test Time (for a fixed config) Motherboard Assembly TBD Seconds +/- TBD Functional Test Script (timer) 5/100 PCBAXbar & R*Refer to Note 2 System with problem can finish test but will retry many times 4Board ThicknessPCB0.062” +/- 10%Micrometer5/100Xbar & R *Refer to Note 1 5Trace WidthPCB0.005” +/- 0.001”Optical venire5/100XBAR & R *Refer to Note 1 6 Impedance measurement PCB SE: 42, 50, 60, 75 DE: 70, 90, 100 TDR 10 for build of 100 20 for build of 1000+ XBAR & R*Refer to Note 1 Best to monitor result per build from PCB vendor 87 SQE Business Process Improvement DEFINE - MONDEO CRITICAL VARIABLES Characteristic SpecificationEvaluation / Measurement Sampling Plan Control Method Process Capability Comments No. Electrical Functionality Product 75V Ripple VoltagePower Supply70mVpp Oscilloscope or Equivalent 5/100 Xbar & R *Refer to Note 1Minimum load 8 5V Ripple VoltagePower Supply70mVpp Oscilloscope or Equivalent 5/100 Xbar & R *Refer to Note 1 Maximum load 912V Rail VoltagePower Supply12V +/- 5%DVM or ICT5/100 UnitsXbar & R*Refer to Note 1Minimum Load 1012V Rail VoltagePower Supply12V +/- 5%DVM or ICT5/100 UnitsXbar & R*Refer to Note 1 Maximum Load 88 SQE Business Process Improvement Characterizing Process Parameters and Product Characteristics Variability (Machine, Methods, Measurements, Materials, People, Environment) SupplierCustomer Feedback (Productivity, Timeliness, Financial, Quality) Process Parameters Product Characteristics Process Parameters and Product Characteristics 89 SQE Business Process Improvement Product and Process Critical Parameters Owner: Engineering, NPI Product Critical Parameters SpecificationsCpk RequirementDPPM estimation MB 1) 2) 3) Commodity #2 1) 2) 3) Commodity #3 1) 2) 3) Owner: Supplier, SQE, Manufacturing Process Critical Parameter SpecificationsCpk RequirementDPPM estimation MB 1) 2) 3) Commodity #2 1) 2) 3) Commodity #3 1) 2) 3) 90 SQE Business Process Improvement Science of Measurement Accuracy - closeness of agreement between an observed value and a standard Precision - closeness of agreement between randomly selected individual measurements 91 SQE Business Process Improvement Repeatability and Reproducibility Repeatability (equipment variation) variation in multiple measurements by an individual using the same instrument. Reproducibility (operator variation) - variation in the same measuring instrument used by different individuals 92 SQE Business Process Improvement Repeatability and Reproducibility Studies Quantify and evaluate the capability of a measurement system Select m operators and n parts Calibrate the measuring instrument Randomly measure each part by each operator for r trials Compute key statistics to quantify repeatability and reproducibility 93 SQE Business Process Improvement R&R Evaluation Under 10% error - OK 10-30% error - may be OK over 30% error - unacceptable 94 SQE Business Process Improvement Measurement Systems Analysis Observed Process Variation Actual Process Variation Measurement Variation Long-Term Process Variation Short-Term Process Variation Within Sample Variation Appraiser Variation (Reproducibility) Gage Variation Cp/Cpk (Capability) SPC (Stability) MSA RepeatabilityCalibrationStabilityLinearity Accuracy at low vs high values Variation over time Bias: deviation of the measured or observed value from the true value Variation when one person measures the same thing several times with the same gage Variation between people using same gage 1 7.62 mm 7.58 mm 1 4 23 1 24 3 Lot ALot BTime 1Time 2 Observed 95 SQE Business Process Improvement Measurement Systems Analysis Attribute MSA Counts of good / bad Dispositions of pass / fail No specification (requires a true- value) Situational interpretation Provide minimal information for control Examples of gages Go / no-go decision Assembly gages Bezel gap gages Templates for dings, dents, and scratches Pixel size templates Variable MSA Physical measurement Instrument Measure of the extent of goodness or badness relative to specifications Standardized interpretation Useful for process capability studies and control Examples of gages Calipers Electrical meter Stopwatches 96 SQE Business Process Improvement Variables MSA Spreadsheet (Gage R&R) 97 SQE Business Process Improvement Average and Range Control Chart 98 SQE Business Process Improvement Average and Range Control Chart Developed from data reported in small subgroups of constant size Subgroups are usually taken at regularly scheduled intervals The range is quite satisfactory for sample sizes up to 10 Usually 3-5 samples per subgroup Grand Average Process average Average of averages Average Range Let R1, R2, ., Rk, be the rang