Accelerated Life Testing of a Commercial Refrigerator Door Handle

Transcription

1 Accelerated Life Testing of a Commercial Refrigerator Door Handle Mike Stasiak Reliability Engineer, Hussmann Corporation michael.stasiak@hussmann.com ASTR 2016, Sep 28-30, Pensacola Beach, FL 1

2 Outline Commercial refrigerator door handle Drivers for ALT of handle Test Development Test Apparatus Failure Modes Key Learning Validation Summary September , Pensacola Beach, Florida 2

3 Commercial Refrigerator Door Handle September , Pensacola Beach, Florida 3

4 Commercial Refrigerator Door Handle Door & Handle Handle Components September , Pensacola Beach, Florida 4

5 Drivers for use of ALT Ability to quickly assess prototype design New thinner handle profile was created for aesthetics New profile was to be rapidly evaluated Ability to swiftly identify any necessary design alteration Future ability to rapidly test design changes (generate accelerated model) September , Pensacola Beach, Florida 5

6 ALT Development Test Setup Use higher stress level to accelerate failures Inverse Power Law Normal stress less than 10 pounds 3 different test stress levels 35 pounds 50 pounds 60 pounds September , Pensacola Beach, Florida 6

7 ALT Development Test Setup 3 different test stress levels 35 pounds 50 pounds 60 pounds September , Pensacola Beach, Florida 7

8 ALT Test Apparatus Setup Compression springs to apply stress at one inch compression Apparatus Pneumatic cylinder advances handles upwards, compressing the springs Force meter connected to a PLC to track cycles and failures September , Pensacola Beach, Florida 8

9 ALT Failure Modes Failure Handle fracture in center of profile Picture Commonly along the mold knit line Fatigue failure September , Pensacola Beach, Florida 9

10 ALT Failure Modes Failure Handle fracture at set screw location Picture Crack initiates on side opposite of set screw Very high cycle fatigue failure September , Pensacola Beach, Florida 10

11 ALT Failure Modes Failure Handle mounting stud fracture at base of mounting stud Picture Very high cycle fatigue failure September , Pensacola Beach, Florida 11

12 Three force levels Reliability Model Less cycles to failure at higher forces Multiple failure modes cause deviations from straight line models September , Pensacola Beach, Florida 12

13 Reliability Model Acceleration factor above the baseline usage force September , Pensacola Beach, Florida 13

14 Reliability Model Unreliability of the failure modes Handle fracture at set screw location is dominant September , Pensacola Beach, Florida 14

15 Key Learning 30 days to develop the model 3 total testing apparatus 90 total handles were tested, 58 failures 30 pound stress: 3 failures out of 13 handles 50 pound stress: 29 failures out of 41 handles 60 pound stress: 26 failures out of 36 handles September , Pensacola Beach, Florida 15

16 Key Learning Model verified by testing handles at design usage for one million cycles Test time reduced from 58 days to 17 hours September , Pensacola Beach, Florida 16

17 Summary Inverse-Power Law generated an accelerated test model All four handle components tested at once ALT yielded a reduced test time for any design or process changes to the handles Thin handle design was qualified for production, no necessary design changes were required as a result of the ALT September , Pensacola Beach, Florida 17

18 References John P. King, William S. Jewett, Robustness Development and Reliability Growth. Boston: Pearson Education, 2010, pp.507. W. Grant Ireson, Clyde F. Coombs Jr., Richard Y. Moss, Reliability Engineering And Management, 2 nd Ed. New York: McGraw-Hill, 1996, pp September , Pensacola Beach, Florida 18

19 Mike Stasiak Mike is a Reliability Engineer II at Hussmann Corporation, Research and Development Department He holds a BS in Mechanical Engineering from Missouri University of Science and Technology September , Pensacola Beach, Florida 19

20 Brian P. Hyde Senior Reliability Engineer at Hussmann Corporation BS Electrical Engineering, University of Illinois Senior Member of the American Society for Quality (ASQ) ASQ Certified Reliability Engineer, Quality Engineer, and Six Sigma Green Belt Reliability and quality experience in refrigeration, electronics, and metal fabrication industries September , Pensacola Beach, Florida 20

21 Questions September , Pensacola Beach, Florida 21