Non-Destructive Joint Testing Equipment Development

1. 05100 - Senior Design Project 05100 – Non-Destructive Joint Test Method & Equipment Development Sponsor: Delphi Automotive – Harrison Radiator Division Team Members: Aleksandra Soldo - IE - Team Leader Lauren Williams - IE Joshua Chan - ME Robert Lefferts - ME Elizabeth A. Kesel - ME Jason Mitchell - EE Thinh Cao - EE

2. Team Members Back (Left to right): Thinh Cao, Lauren Williams,Robert Lefferts,Jason Mitchell Front (Left to right): Aleksandra Soldo,Elizabeth A. Kesel, Joshua Chan

3. Scope • Develop a non destructive test method and equipment/tools to verify the long term integrity of the clinch portion of a heater core pipe to neckshell assembly for an assembly process in a production environment. • Understand/Define the correlation between Joint Integrity and the pressure & temperatures at which they will leak. Develop a test method for production environment. • How to accurately measure clinch.

4. Long-term Objectives • Improve overall quality throughout the process by providing useful data and an accurate measurement system. • Reduce process variation to be more cost effective and efficient. • Help Delphi improve customer relations through improved product quality.

5. Parameters and Deliverables Clinch Measurement System • Must be non destructive. • Must be applicable to the HC 340 and all heater core assemblies. • The cost of equipment must not exceed $75,000. • Must meet operator safety requirements as well as be ergonomically acceptable and environmentally friendly. • Must be integrated within the planned assembly/test process. • Equipment must pass MSA (measurement system analysis). • Must not adversely effect performance of joint or heater core assembly for use by the customer for the life of the product. • Must be in production by April 2005. • Test must be conducted within cycle time of production assembly (~20 sec). • Clinch vs. Leak Correlation • Statistical proof of correlation between clinch and leak.

6. Clinch Information • Delphi has a 2 mm maximum clinch gap specification. • Each heater core has 2 joints. 3 clinches are used at each joint. • Clinch gap is currently measured 4 times per shift by hand. • Poor clinches are failed through physical inspection. 2.0 MAX TYP NECK SHELL O-RING

7. Testing Feasibility – Preparations Explained Test Plan 1 and 3 • Delphi will randomly selected X number of “good” and “bad” heater cores from production throughout the duration of one week. (“good” meaning no clinch is > 2mm, and core is not leaking. “Bad” meaning otherwise) • For Test Plan 1, x =30 • For Test Plan 2, x=90 (50 good, 40 bad) • 35 parts from each good/bad category will be randomly selected for the test. • All 6 clinches on each core will be labeled, measured and recorded. Test Plan 2 • Delphi will randomly select a (large) number of “good” and “bad” heater cores from production throughout the duration of one week. (“good” meaning no clinch is > 2mm, and core is not leaking “Bad” meaning otherwise) • All 6 clinches on each core will be labeled, measured and recorded. • Heater cores will be categorized according to measurements into one of the three “Gap-Ranges” n (Ranges n = 1,2 or 3) • Range 1 (very bad clinches) – core have at least one clinch gap larger than 2.5mm • Range 2 (very good clinches) – core has all clinch gaps smaller than 1.5mm • Range 3 (middling clinches) – core doesn’t fall in the either one of the above categories • Perform Leak test at room temperature for all the cores, and separate the cores that have a leak > 6cc. • Randomly select parts from category n for particular temperature/pressure combination.

8. Testing Feasibility – Procedures Explained Test parts sequentially at 25 psi, 35 psi, 45 psi, 55 psi at sequentially increased temperatures: (74º F, 175º F, 225º F, 250º F). All parts go together through the complete sequence of testing. • X represents the number of cores used to testing. • All X are same, meaning each cell will contain results obtained from the same cores.

9. Testing Feasibility – Procedures Explained (cont.) Test parts randomly at 25 psi, 35 psi, 45 psi, 55 psi at temperatures randomly adjusted to 74º F 175º F, 225º F and 250º F.Each part exposed to only one set of conditions • Xnij stands for number of cores from Range n (n = 1, 2, or 3) that become exposed to the same pressure(i)/temperature(j) combination. • All X are same in size, meaning each cell will have same number of cores. (For X = 5 (meaning 5 cores per cell), and since n = 3 (meaning 3 gap ranges), and number of cells = 16 total number of cores needed would = 240.)

10. Feasibility Analysis • Test Plan 1 is the “Base” with automatic ratings of 3. • The scale 1-5 for individual ratings represents the ratings of 5 being the best and 1 being the worst • Based on the ratings above the decision is to use Test Plan 3 as it has the highest total rating that is better than the Base.

11. Leak Test Procedure • Outlet pipe on all 70 heater cores are sealed with a rubber stopper and JB weld. • Heater cores are allowed to cure over night.

12. Testing Setup

13. Testing Obstacles • The cores, not the clinches were leaking • There was too much movement in the heater core pipes causing stress in the clinch • Internal leaks in the measurement system • Un-calibrated equipment • Faulty equipment The mass flow meter we were using was not rated for our temperatures

14. Alternate Leak Test Setup Pressure decay test was setup to use a flow meter acquired from Delphi Thermal & Interior Due to time constraints we never got this setup working properly

15. Testing Procedure • All 6 clinch gaps were measured using gauge pins • Outlet pipes were sealed with rubber stoppers secured with JB Weld • Gage R&R was performed on testing equipment

16. Testing Analysis • Minitab analysis • Regression analysis • Nonparametric analysis • Removed outliers • Box-Cox Transformation

17. Data Limitations • Limited Units for Testing • Given no memory effects in the cores, a single unit experienced all temperatures and pressures. • Time Constraints • Each unit experienced testing conditions in same order. Randomization, in this aspect, was not feasible. • Not able to take into account nuisance variables associated with day to day variance of testing equipment

18. Bad part cut-off Difference between bad and good part leak rates (outliers included) 2.0 mm (current) (0, .3) sccm 2.5 mm (0, .3) sccm 3.0 mm (.04, .7 sccm) Testing Analysis – Conclusions Good-Bad

19. Testing Analysis – Conclusions (cont.) • There is a positive relationship between median values of leak rate for each pressure and the values vary between .55 sccm and 1.2 sccm. • Whether or (the average left pipe clinch gap) account for about 16% of the variability in leak rate with outliers and 46.4% without them. • The ANOVA and regression assumptions of identically distributed sample populations are grossly violated in the original model, but are borderline acceptable with Box-Cox transformed data. • Comparing the room temperature leak rates shows that the parts have the same leak rates before and after the temperature extremes and there may be reason to believe there are no “memory” effects due to prior testing.

20. Suggested Future Test Plan Example And so on until each treatment combination has been tried n times

21. Camera System Verification • Camera system was mounted and calibrated (X and Y axis) with a distance of 6.5 inches. • Heater cores were placed and images taken and measured. • Three different operators of system to get repeatability and reproducibility. • Measurements recorded and entered in Gage R&R spreadsheet from Delphi.

22. Financial Analysis for Clinch Measurement System • Delphi allocated $75,000 for system • Cost of CV-2100 Vision System: $8,000-$11,000 • Two systems will be required • Total Implementation Cost: $16,000-$22,000 • Minimum percentage of budget: 21% • Maximum percentage of budget: 29% • System is within budget

23. Accomplishments & Conclusions • Developed an understanding of project definition and scope • Developed concepts to meet project deliverables • Completed feasibility assessment • Presented preliminary design concepts in front of a panel • Completed testing feasibility • Conducted testing • Performed extensive statistical analysis • Gave sponsor documented information about their problem • Proposed a future course of action for sponsor

24. Additional Questions?

25. Metal Memory Test One-Sample T: D25, D35, D45, D55 Test of mu = 0 vs mu not = 0 Variable N Mean StDev SE Mean D25 10 0.0200 0.3120 0.0987 D35 10 0.130 0.330 0.104 D45 10 0.0500 0.2369 0.0749 D55 10 0.110 0.486 0.154 Variable 95.0% CI T P D25 ( -0.2032, 0.2432) 0.20 0.844 D35 ( -0.106, 0.366) 1.25 0.245 D45 ( -0.1195, 0.2195) 0.67 0.521 D55 ( -0.238, 0.458) 0.72 0.493 P/N 25 PSI before 35 PSI before 45 PSI before 55 PSI before 25 PSI after 35 PSI after 45 PSI after 55 PSI after D25 D35 D45 D55 21b 0.2 0.6 0.6 0.7 0.5 0.7 0.5 0.9 0.3 0.1 -0.1 0.2 4b 0.7 1.0 1.2 1.4 0.3 0.9 1.4 1.9 -0.4 -0.1 0.2 0.5 22g 0.4 0.9 1.4 1.7 0.6 0.8 1.5 2.1 0.2 -0.1 0.1 0.4 11g 1.0 1.1 1.8 2.2 0.8 1.0 1.5 1.7 -0.2 -0.1 -0.3 -0.5 19b 0.5 0.6 0.6 0.7 0.7 0.7 0.9 1.0 0.2 0.1 0.3 0.3 37b 0.9 0.9 1.1 1.3 0.7 1.2 1.2 0.7 -0.2 0.3 0.1 -0.6 34b 1.7 2.3 3.6 4.8 2.2 3.2 4.0 5.7 0.5 0.9 0.4 0.9 18g 0.6 0.8 0.9 1.0 0.3 0.8 1.1 1.4 -0.3 0.0 0.2 0.4 8g 0.8 1.0 1.1 1.1 0.6 0.8 0.9 0.9 -0.2 -0.2 -0.2 -0.2 9b 0.2 0.7 1.3 1.5 0.5 1.1 1.1 1.2 0.3 0.4 -0.2 -0.3

26. Mood Median Test: Leak Rate (Sccm) versus Has Bad Clinch Mood median test for Leak Rate Chi-Square = 7.43 DF = 1 P = 0.006 Individual 95.0% CIs Has Bad N<= N> Median Q3-Q1 -+---------+---------+---------+----- 0 83 44 0.800 0.500 +---------) 1 51 56 1.000 0.600 (---------+---------) -+---------+---------+---------+----- 0.80 0.90 1.00 1.10 Overall median = 0.900 A 95.0% CI for median(0) - median(1): (-0.300,0.000) Clinch Gap Correlation

27. Clinch Gap Correlation (cont).

28. Pressure Correlation Mood median test for Leak Rate Chi-Square = 70.19 DF = 3 P = 0.000 Individual 95.0% CIs Pressure N<= N> Median Q3-Q1 ----------+---------+---------+------ 25 51 5 0.550 0.300 (-+-) 35 43 13 0.800 0.200 (---+ 45 30 26 0.900 0.300 +---) 55 10 45 1.200 0.500 (+----) ----------+---------+---------+------ 0.75 1.00 1.25 Overall median = 0.900 223 cases were used 4 cases contained missing values Kruskal-Wallis Test on Leak Rate Pressure N Median Ave Rank Z 25 56 0.5500 53.9 -7.78 35 56 0.8000 97.1 -2.00 45 56 0.9000 125.8 1.84 55 55 1.2000 172.3 7.98 Overall 223 112.0 H = 98.94 DF = 3 P = 0.000 H = 99.75 DF = 3 P = 0.000 (adjusted for ties) Leak Rate (Sccm) = 0.0465 + 0.0217 Pressure(psi) Predictor Coef SE Coef T P Constant 0.04646 0.07393 0.63 0.530 Pressure 0.021700 0.001783 12.17 0.000 S = 0.2971 R-Sq = 40.1% R-Sq(adj) = 39.9% Analysis of Variance Source DF SS MS F P Regression 1 13.078 13.078 148.12 0.000 Residual Error 221 19.514 0.088 Total 222 32.592

29. Box-Cox Transformation

30. Verification of ANOVA