Application of Failure Mode and Effect Analysis to the Powder Coat Process

1. Application of Failure Mode and Effect Analysis to the Powder Coat Process Joan Burtner Department of Mechanical and Industrial Engineering Mercer University, Macon, GA

2. Paint Cell Project • Interdisciplinary team • Industrial management • Industrial engineering • Technical advisor - Joan Burtner • External client • Georgia manufacturer • Practices Six Sigma philosophy Presenter: Dr. Joan Burtner, Mercer University

3. Powder Coat Process Overview • Material - powdered paint • Two basic application methods • Part is lowered into a fluidized bed of the powder, which is electrostatically charged • Powdered paint is electrostatically charged and sprayed onto the part • Curing • Part placed in an oven - powder particles melt and form a continuous film Presenter: Dr. Joan Burtner, Mercer University

4. Powder Coat Equipment • Spray Gun • Corona charging guns -electric power used to generate the electrostatic charge • Tribot charging guns - electrostatic charge generated by friction between the powder and the gun barrel • “Bell” charging guns -powder charged by being "flung" from the perimeter of the "bell Presenter: Dr. Joan Burtner, Mercer University

5. Powder Coat Facility Typical Spray Booth Courtesy:www.thefabricator.com Accessed March 12, 2004 Presenter: Dr. Joan Burtner, Mercer University

6. Quality Issues • Surface preparation • Operators • Training • Skill • Coverage • Color change • Cleanliness/ contamination Presenter: Dr. Joan Burtner, Mercer University

7. Preliminary Process Map Load Wash Dry Paint Cure Rework Accept Unload Presenter: Dr. Joan Burtner, Mercer University

8. Key Customer Requirements • Minimal paint thickness • Even coverage • Scratch-free parts Presenter: Dr. Joan Burtner, Mercer University

9. Cause and Effect Matrix * Correlation values 0, 1, 3, 9 **Sample calculation 7*3+9*3+10*3=78 Presenter: Dr. Joan Burtner, Mercer University

10. Control Charting Deliverables • Target Factor - paint thickness • Data collection plan • Documentation of plan as standard operating procedure • Control chart training materials • Control charts of baseline data Presenter: Dr. Joan Burtner, Mercer University

11. Control Charting Locations • Factor - paint thickness • 5 locations • Repeated measures • 25 samples for baseline chart North West Middle East South Presenter: Dr. Joan Burtner, Mercer University

12. Control Charting Sample Preliminary • Range not in control Presenter: Dr. Joan Burtner, Mercer University

13. Control Charting Sample Results - Revised • Range in control Xbar not in control Presenter: Dr. Joan Burtner, Mercer University

14. Designed Experiments • Dependent variable - paint thickness • Factor 1 - location • Factor 2 - shift • Statistical software package - Minitab Presenter: Dr. Joan Burtner, Mercer University

15. Failure Modes and Effects Analysis (FMEA) Techniques • 48 process steps selected for investigation • 4 experts polled • Operators • Management • Ratings entered into basic FMEA worksheet • RPNs calculated • Process steps ranked by RPN (high to low) Presenter: Dr. Joan Burtner, Mercer University

16. Failure Modes and Effects Analysis - Category Ratings 1 • Severity of Effect (10-1) • Hazardous without warning • Hazardous with warning • Loss of primary function • Reduced primary function performance • Loss of secondary function • Reduced secondary function performance • Minor defect noticed by most customers • Minor defect noticed by some customers • Minor defect noticed by discriminating customers • No effect Presenter: Dr. Joan Burtner, Mercer University

17. Failure Modes and Effects Analysis - Category Ratings 2 • Likelihood of Occurrence • 9 Very High: Almost inevitable • 7 High: repeated failures • 4 Moderate: Occasional failures • 2 Low: Relatively few failures • 1 Remote: Failure is unlikely Presenter: Dr. Joan Burtner, Mercer University

18. Failure Modes and Effects Analysis - Category Ratings 3 • Ability to Detect (10-1) • Cannot detect 10 • Very remote chance of detection • Remote chance of detection • Very low chance of detection • Low chance of detection • Moderately high chance of detection • High chance of detection • Very high chance of detection • Almost certain detection 1 Presenter: Dr. Joan Burtner, Mercer University

19. Risk Priority Number Example Calculations • Paint Material – accident or transport failure • Potential Failure Effect • Lack of paint consistency • Severity of Effect rating 4 • Potential Cause • Dropped powder • Likelihood of Occurrence rating 3 • Current Control • Lifting procedures • Ability to Detect rating 3 • Severity*Likelihood*Detection = 36 = RPN Presenter: Dr. Joan Burtner, Mercer University

20. Failure Modes and Effects Analysis Results • Ratings ranged from 300s to 20s • Uncontrolled process steps eliminated • Critical controlled process steps • Powder application - operator • Cure process • Powder application - spray gun • Loading • Unloading Presenter: Dr. Joan Burtner, Mercer University

21. Control Plan Worksheet • Critical to Quality (CTQs) factors listed according to RPN ranking • Process step as listed in process map • Inputs/outputs • Process specifications • Measurement system • Current control plan • Control method • Who • Where • When • Reaction plan Presenter: Dr. Joan Burtner, Mercer University

22. Control Plan Follow-up • Revision of current standard operating procedures (SOP) • Establishment of standard operating procedures for CTQs that do not already have an SOP • Periodic review Presenter: Dr. Joan Burtner, Mercer University