DOE ApplicationsOct 16th 2002ASQ Section 702: San Gabriel ValleybyDr. Raj Palanna
Objective of Talk❚Give a “flavor”for actual applications of DOE in industry❚Provide an insight into how complex theoretical concepts are applied in real-world situations❚Build on the ASQ 702 September presentation DOE -Basic Concepts by Dr. Kurt Palmer
Agenda❚Deep Dive -2 Examples❚Quick High Level Overview -Few More Applications❚Q&A* These examples are taken from applications at different companies. Some of the data and facts have been “coded”to protect proprietary information.
1. ECS Pack Switch Failure Investigation❚Starting February 2002 (until April 2002) a total of 21 switches have been rejected at XXX Aircraft Company’s aircraft test line, for failure to “open”at max. 200deg. F.❚Shipments of multi million dollar aircraft are at risk
Key Planning Aspects❚Immediate containment actions taken❚Teams working at 3 tiers of supply chain❚Evaluate the “usual suspects”*❙Testing setup and process❙Manufacturing process❙Application at system level, etc❚Different schools of quality uses slightly different methods for this exercise* This presentation will concentrate only on the DOE aspect of theproblem
DOE Problem Statement❚Parts that failed at customer passed at supplier test process. Test method is a suspect. A DOE was set up to understand the sensitivity of switches to the test parameters❚6 Parts were chosen for DOE -3 New, 3 Rejected
DOE Pre-planing ❚A complex DOE THOUGHT MAP was developed❙Factor Selection❙Response Selection❙Measurement Repeatability Studies❙Noise Impact❙Confounding❙Randomization❙Resource Logistics❙Management Approvals❙Observation/ Copious Notes❙etc
DOE Orthogonal Matrix Building Exercise❚You Have Been Tasked to Optimize Gas Mileage on Your Car❙Team Needs to Test 4 Factors❙Has Resources for 8 Runs❙Res. IV Confounded Design in Acceptable (Don’t worry if you don’t understand this bullet!!)❚What is the DOE Matrix?
4-12ResIVDOE MatrixFactor AFactor BFactor CFactor DResponseDepth of Oil Type/ Switch Viscosity Mounting OutputOutputOutputOutputOutputOutputAverage Average Average Run #Test #(Plate)Ramp Rate(Flow)TechniqueSN 1SN 2SN 3SN 4SN 5SN 6"Good""Rejected'TotalDC 200 DC 200 72Submerged210CSTSet 200 63Submerged1010CSTSet DC 200 210 35Submerged2100CSTSet DC 210 210 DC 210 48Submerged10100CSTSet
DOE Analysis:“Rejected”Switches Average Trigger TemperatureMain Effects Plot - Boeing Rejected Switches (F)Interaction Plots - Boeing Rejected Switches (F)C000 1 1de00nd0122Oa e tr0CCeh21DDSTdTTeSgSCredC0Plate00210me11brg d00ue01nedS m 22Oa tbetoru20CCehNS 1DDSTSubmerged224200Not Submer190219Ramp Rate210102002142190Oil Type209210DC 210 100200DC 200 10C204190PlateRamp RateOil TypeMountingMountingPareto Chart of the EffectsNormal Probability Plot of the Effects(response is REJECTED, Alpha = .30)(response is REJECTED, Alpha = .30)A:PlA::Ramp RatB:Ramp RatDC:Oil TypeC:Oil TypeD:MountingD:-20-1001020Effect01020Type of TESTING OIL (C) influences test results and Type of MOUNTING (D) influences test resultsNormal ScoreREJECTED
DOE Analysis:“New”Switches Average Trigger TemperatureMain Effects Plot - 'Good' Switches (F)Interaction Plots - 'Good' Switches (F)C000d 1 1e00nd0122Oa e ru00e01nedS22Oa m tbetrou20CCehNS 210 200 RateOil TypeMountingMountingPareto Chart of the EffectsNormal Probability Plot of the Effects(response is GOOD, Alpha = .30)(response is GOOD, Alpha = .30):PlateA:PlateCB:Ramp RatB:Ramp RatCC:Oil TypeC:Oil TypeD:MountingD:-3-2-10123BEffect0123No Impact of Factors A, B, C and D on “New”SwitchesGOODNormal Score
Spread of Results Under Different Testing ConditionsSwitches from New BatchTest Parameters Outside ATP - Trigger Temp Spread 14353Test Parameters Outside ATP - Trigger Temp Spread 14412Test Parameters Outside ATP - Trigger Temp Spread 15235LSLUSLLSLUSLLSLUSLProcess DataProcess DataProcess *Target *Target * N8Sample N8Sample N8StDev (ST) (ST) (ST) (LT) (LT) (LT) (ST) CapabPotential (ST) CapabilityPotential (ST) * *Cpm *180185190195200205185187189191193180185190195200Overall (LT) CapabilityObserved PerformanceExpected ST PerformanceExpected LT PerformanceOverall (LT) CapabOverall (LT) CapabilityObserved PerformanceExpected ST PerformanceExpected LT PerformanceilityObserved PerformanceExpected ST PerformanceExpected LT < LSL < LSL < LSL < < < < LSL < LSL < > USL > USL > > > > > USL > USL > USL Total Total Total Total Spread Has been Switches from Customer ‘Rejected”BatchObserved in “Rejected Switches”Test Parameters Outside ATP - Trigger Temp Spread 14935Test Parameters Outside ATP - Trigger Temp Spread 15007Test Parameters Outside ATP - Trigger Temp Spread 14954LSLUSLProcess DataLSLUSLLSLUSLProcess * * * N8Sample N8Sample N8StDev (ST) (ST) (ST) (LT) (LT) (LT) (ST) CapabilityPotential (ST) CapabilityPotential (ST) CapabilityCp *Cpm *150170190210230250270150170190210230250270Cpm *150170190210230250270Overall (LT) CapabilityObserved PerformanceExpected ST PerformanceExpected LT PerformanceOverall (LT) CapabilityObserved PerformanceExpected ST PerformanceExpected LT PerformanceOverall (LT) CapabilityObserved PerformanceExpected ST PerformanceExpected LT PerformancePp < LSL < LSL < LSL < LSL < LSL < LSL > > > < LSL < LSL < LSL > > > > > >
Historical Reviewof Test Data to Evaluate ProcessITT ATP Data 641121, Jan 1999 - Mar 2002 (Actuation)210205High Variation?200195190185180175170Test #Degree F113426740053366679993210651198133114641597173018631996212922622395252826612794292730603193332634593592372538583991412442574390452346564789
Conclusions❚A particular batch of switches were found to be in under-fill condition and switches became “sensitive”to testing parameters/ operating conditions and lost its robustness to environment❘Manufacturing process was fixed❘Test was augmented to prevent this situation from happening again
2. Aircraft Motor Performance Optimization❚Problem statement: shop failures at test. Brake was releasing under the “brake release voltage specification”❚Evaluate the “usual suspects”❙Testing setup and process❙Manufacturing process❙Application at system level, etc❚Developed a DOE thought map
5-12ResIVDOE Matrix .. MotorInput FactorsOutputAverageStatic ABCED=ABCStatic Brake Brake Static Brake(in-Run #Kit #CWCCWoz)Disk FlatnessArmature TIRBrake GapRun InEnd
Main Effects for DOE Part 2DiskFlatArmTIRBrake GapRun-InEnd - - - - - Use :•Run-In•High Armature TIR•Flat DiskStatic Brake
Interaction Plot for DOE 211111111- - - - 18DiskFlat 113-1 818ArmTIR 113-1 818Brake Gap 113-1 818Run-In 113-1 8End PlayWith Low Disk Flatness Use 3 mm (Low) End-Play.
Test for Statistical SignificancePareto Chart of the Effects(response is Static B, Alpha = .30)A:DiskFlatDB:ArmTIRC:Brake GaBD:Run-InAEE:End PlayAACABDCABBDDECDACDADEADE012345Normal Probability Plot of the Effects(response is Static B, Alpha = .30)A:DiskFlatDB:ArmTIRC:Brake GaD:Run-InAEE:End Play10-1AB-4-3-2-10123456EffectResults Are Statistically SignificantNormal Score
Randomness TestResiduals Versus the Order of the DataResiduals Versus the Fitted Values(response is Static B)(response is Static B)1100-1-1101520246810121416Fitted ValueObservation OrderNormal Probability Plot of the ResidualsHistogram of the Residuals(response is Static B)(response is Static B)-101ResidualResidualThere is No Unusual ObservationsNormal ScoreResidualResidualFrequency
Conclusions -Motor DOE❚Experiment showed statistical significance.❚Settings for Static Brake❘Brake Cycling….Introduce Brake Cycling in MOT-Chuck❘High Armature TIR.???? Do we ask for “bad parts”?❘Flat Disk….Within 1/10th..Need Process Control❘With Low Disk Flatness Use 3 mm(Low) EndPlay. (With Flat Disk Set Low EndPlay). Change MOT -Chuck.❚This will improve Static Brake Problems.
3. Nozzle Air Flow Optimization DOE❚Problem statement: air cycle machine nozzle hole-to-hole variation need to be minimized to improve system performance❚Process: multi spindle drilling❚DOE response: diameter sigma between different holes in a single nozzle❚Factors: machining factors❙Reamer speed, Reamer feed, Reamer diameter, Stock (after drilling)
4. Vapor Cycle Pack Bearing Failure Investigation❚Problem statement: bearing failures of VCS pack on aircraft❚Type of DOE: design robustness evaluation❚Response: measure of fatigue on the bearing after specified run time❚DOE factors: product design variables
5. DOE for Car Door Panel Delimitation Problem❚Problem statement: delaminating of vinyl from the foam substrate of an car door interior❚Process: door panel molding process❚Response: lamination evaluation on alikertscale + measure of area of delaminating❚DOE factors: molding machine factor❙Overall temp, Heat upper, Heat lower, Oven temp, Backing type, Density, Vacuum pressure, Vacuum delay
6. Actuator Pin Alignment DOE❚Problem statement: aircraft door actuator connector pin alignment out of specification❚Type of DOE: combination assembly process evaluation plus design features evaluation❚DOE response: distance from nominal in circular domain❚DOE factors: assembly technique variables plus part features❙Twist, Length, Sleeve
Practice Idea:Gas Mileage Optimization DOE❚Problem statement: pick a response variable to optimize on the car (gas mileage…)❚Choose factors that might influence this output response variable❚Setup the DOE, run the DOE, analyze DOE❚Other ideas:❙Optimize volume of popcorn produced❙Etc……. Any suggestions from audience? DOE Is Not the Easiest Application Tool Around Town….But If You Master DOE, You Will Be a Champion QE!!Practice, Practice, Practice
Appendix❚Reference Books❙Douglas C. Montgomery: Design and Analysis of Experiments❙Ronald D. MoenEt Al.: Improving Quality Through Planned Experimentation❙Madhav : Quality Engineering Using Robust Design❚Software❙Minitab❙JMP❙Etc
