1. Study of Surface Porosity
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
Study of Surface Porosity
Using Reconfigurable Inspection Machine (RIM)
The University of Michigan, Ann Arbor

2. Surface Porosity Inspection – Research Objectives
Establish a methodology necessary for non-contact inspection of porosity defects.
Determine if the above methodology can reliably detect porosity defects according to GM/DCX specifications.
Determine if the above methodology can be implemented in-line (i.e. at line rates).
Validate the method with production cylinder heads and blocks.

3. Background: Why Inspect Engine Cylinder Heads ?
Areas on the deck face of an engine cylinder head are isolated one from the other to prevent the mix of water, oil and combustion gasses.
Fire ring
Sealing Bead
Gasket body

4. Porosity Inspection is Currently Performed by Human Inspectors

5. Reconfigurable Inspection Machine (RIM)
Vision Sub System for Porosity Inspection
Vision Sub System for Porosity Inspection
Illumination System
CCD Line Scan Camera
U.S. Patent #6,567,162 B2 Yoram Koren, Reuven Katz

6. System Operation
Controller Module
Inspection Module
Vision System

7. Easy to use User interface and Automatic Analyze and Decision
Zoom Window for Pore Analysis
Defects Highlighted in Red

8. Surface Porosity Inspection Study Achievements (1 of 2)
Developed a Reconfigurable Inspection Machine (RIM) for porosity inspection on cylinder heads.
Developed algorithms, software for detecting and classifying surface porosity. (Able to classify pores by diameter, x-y location, and specification region.)
Conceptualized a method for depth validation of detected pores using side lightning.

9. Surface Porosity Inspection Study Achievements (2 of 2)
Able to detect pores with diameter > 300 micrometer.
Able to detect isolated and edge-connected pores on aluminum and cast-iron parts.
Created a user-friendly software interface for reporting and analyzing defects.
Created a software tool for assessing the repeatability of the porosity inspection system.
As a result of this research GM built an inspection machine and DCX is testing it in a plant.

10. System Evaluation at GEMA
Over 600 engine blocks were inspected by the RIM.
85% of bad parts were correctly rejected. (15% missed detections due to defects other than pores and template misalignment)
90% of good parts were correctly accepted. (10% false alarms mainly due to template misalignment)

11. Future work Inspection of porosity on pistons and cylindrical parts
Defect inspection on auto-body panels
Combustion chamber volume measurements
Improvements of RIM performance reliability

12. Questions are welcomed
The End
Questions are welcomed