Presentation on theme: "DOE Applications Oct 16th 2002 ASQ Section 702: San Gabriel Valley by Dr. Raj Palanna."— Presentation transcript:
DOE Applications Oct 16th 2002 ASQ Section 702: San Gabriel Valley by Dr. Raj Palanna
Objective of Talk zGive a “flavor” for actual applications of DOE in industry zProvide an insight into how complex theoretical concepts are applied in real- world situations zBuild on the ASQ 702 September presentation DOE - Basic Concepts by Dr. Kurt Palmer
Agenda zDeep Dive - 2 Examples zQuick High Level Overview - Few More Applications zQ&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 zStarting 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. 200 deg. F. zShipments of multi million dollar aircraft are at risk
Key Planning Aspects zImmediate containment actions taken zTeams working at 3 tiers of supply chain zEvaluate the “usual suspects”* yTesting setup and process yManufacturing process yApplication at system level, etc zDifferent schools of quality uses slightly different methods for this exercise * This presentation will concentrate only on the DOE aspect of the problem
DOE Problem Statement zParts 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 z6 Parts were chosen for DOE - 3 New, 3 Rejected
DOE Pre-planing zA complex DOE THOUGHT MAP was developed yFactor Selection yResponse Selection yMeasurement Repeatability Studies yNoise Impact yConfounding yRandomization yResource Logistics yManagement Approvals yObservation/ Copious Notes yetc
DOE Orthogonal Matrix Building Exercise zYou Have Been Tasked to Optimize Gas Mileage on Your Car yTeam Needs to Test 4 Factors yHas Resources for 8 Runs yRes. IV Confounded Design in Acceptable (Don’t worry if you don’t understand this bullet!!) zWhat is the DOE Matrix?
DOE Analysis: “Rejected” Switches Average Trigger Temperature Type of TESTING OIL (C) influences test results and Type of MOUNTING (D) influences test results
DOE Analysis: “New” Switches Average Trigger Temperature No Impact of Factors A, B, C and D on “New” Switches
Switches from New Batch Switches from Customer ‘Rejected” Batch Spread of Results Under Different Testing Conditions Higher Spread Has been Observed in “Rejected Switches”
Historical Review of Test Data to Evaluate Process
Conclusions zA 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 xManufacturing process was fixed xTest was augmented to prevent this situation from happening again
2. Aircraft Motor Performance Optimization zProblem statement: shop failures at test. Brake was releasing under the “brake release voltage specification” zEvaluate the “usual suspects” yTesting setup and process yManufacturing process yApplication at system level, etc zDeveloped a DOE thought map
With Low Disk Flatness Use 3 mm (Low) End-Play.
Test for Statistical Significance Results Are Statistically Significant
Randomness Test There is No Unusual Observations
Conclusions - Motor DOE zExperiment showed statistical significance. zSettings for Static Brake xBrake Cycling….Introduce Brake Cycling in MOT- Chuck xHigh Armature TIR.???? Do we ask for “bad parts”? xFlat Disk….Within 1/10th..Need Process Control xWith Low Disk Flatness Use 3 mm(Low) EndPlay. (With Flat Disk Set Low EndPlay). Change MOT - Chuck. zThis will improve Static Brake Problems.
3. Nozzle Air Flow Optimization DOE zProblem statement: air cycle machine nozzle hole-to-hole variation need to be minimized to improve system performance zProcess: multi spindle drilling zDOE response: diameter sigma between different holes in a single nozzle zFactors: machining factors yReamer speed, Reamer feed, Reamer diameter, Stock (after drilling)
4. Vapor Cycle Pack Bearing Failure Investigation zProblem statement: bearing failures of VCS pack on aircraft zType of DOE: design robustness evaluation zResponse: measure of fatigue on the bearing after specified run time zDOE factors: product design variables
5. DOE for Car Door Panel Delimitation Problem zProblem statement: delaminating of vinyl from the foam substrate of an car door interior zProcess: door panel molding process zResponse: lamination evaluation on a likert scale + measure of area of delaminating zDOE factors: molding machine factor yOverall temp, Heat upper, Heat lower, Oven temp, Backing type, Density, Vacuum pressure, Vacuum delay
6. Actuator Pin Alignment DOE zProblem statement: aircraft door actuator connector pin alignment out of specification zType of DOE: combination assembly process evaluation plus design features evaluation zDOE response: distance from nominal in circular domain zDOE factors: assembly technique variables plus part features yTwist, Length, Sleeve
Practice Idea: Gas Mileage Optimization DOE zProblem statement: pick a response variable to optimize on the car (gas mileage…) zChoose factors that might influence this output response variable zSetup the DOE, run the DOE, analyze DOE zOther ideas: yOptimize volume of popcorn produced yEtc……. 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 zReference Books yDouglas C. Montgomery: Design and Analysis of Experiments yRonald D. Moen Et Al.: Improving Quality Through Planned Experimentation yMadhav S. Phadke: Quality Engineering Using Robust Design zSoftware yMinitab yJMP yEtc