Engineering Research Center for
Reconfigurable Manufacturing Systems
In-Line Engine Valve Seat Inspection
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
Motivation
Critical dimensional and geometric features
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•
•
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Seat Angle (with respect to valve guide)
Seat Length
Roundness of critical seat
Run-out of critical seat (with respect to valve guide)
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
2
Currently Used Techniques
Coordinate Measuring Machine
Specialized Dial Indicator
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
3
Project Goal
• In-line measurement of valve seat geometry (cycle time ~ 30 seconds)
• Rapid and accurate non-contact measurement
• Measurement of seat angle and seat length from cross section
• Measurement of roundness from multiple cross sections
• Measurement of run-out with respect to valve guide
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
4
Preliminary Setup
Current Setup
• 2-axis Aerotech motion stage system
• Optimet Conoprobe: single point laser range sensor
Future Setup
• Addition of 3rd axis system for multiple cross sections
• Portable demonstrator (ME450: senior design class)
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
5
Algorithm for Angle Measurement
Data Acquisition
• Data acquired from a single independent valve seat insert
• Outliers filtered using Conoprobe’s inbuilt SNR filter
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
6
Algorithm for Angle Measurement
Angle Calculation wrt Horizontal Reference
• Linear least squares fit for each angle
• Estimate angle with respect to horizontal
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
7
Algorithm for Angle Measurement
Angle Calculation wrt Imaginary Datum
• Determine horizontal plane based on intersection points
• Horizontal plane used as imaginary datum (instead of valve guide axis)
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
8
Algorithm for Angle Measurement
1
2
Angle Calculation wrt Imaginary Datum
• Determine horizontal plane based on intersection points
• Horizontal plane used as imaginary datum (instead of valve guide axis)
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
9
Preliminary Results
Run 1
Angles with respect to
horizontal reference
Angle with respect to
imaginary datum
29.17
45.16
60.74
44.88
30.38
44.41
59.07
44.69
Run 2
Angles with respect to
horizontal reference
Angle with respect to
imaginary datum
29.64
45.11
60.68
44.83
30.63
44.41
58.97
44.68
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
10
Off-Center Measurements
• Current: Measurement along diameter
• Future: Mathematical adjustment for off centered measurement
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
11
Roundness Measurement
• Extract intersection points from multiple cross sections
• Estimate roundness from best fit circle
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
12
Next Steps
• Run tests and measurements using newly fixed motion stages
• Repeat repeatability study and accuracy analysis with existing valve seat
samples
• ME450 Design project (September to December)
• 4 undergraduate design students
• Design and build an in-line demonstrator for valve seat measurement
• Investigate and perform feasibility study
• Run-out measurement using integrated vision system
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering
13
Thank You!
Questions and Comments ??
NSF Engineering Research Center for Reconfigurable Manufacturing Systems
University of Michigan College of Engineering