Fringe analysis approach for imaging surface undulations on technical surfaces.
Optics Express
|November 23, 2021
Summary
This study introduces a novel imaging technique for automated defect inspection in manufacturing. It effectively detects surface defects and undulations on challenging samples, like hard disk drive platters, by using LED fringe patterns.
Area of Science:
- Manufacturing Engineering
- Optical Metrology
- Surface Inspection
Background:
- Automated defect inspection is crucial for reducing costs in advanced manufacturing.
- Early-stage production samples present challenges due to tooling marks and scattering.
- Existing inspection methods struggle with complex surface features.
Purpose of the Study:
- To develop a new imaging technique for enhanced automated defect inspection.
- To overcome limitations of current methods for early-stage manufacturing samples.
- To enable detection of both surface defects and undulations using a single apparatus.
Main Methods:
- An adapted fringe projection technique using an LED array.
- Exploiting preferential scattering from technical surfaces to create fringe patterns.
- Employing phase shifting algorithms to reconstruct surface topography.
Main Results:
- Successfully generated predictable fringe patterns on samples with tooling marks.
- Demonstrated imaging of both scattering pits/scratches and surface undulations.
- Validated the technique on Hard Disk Drive (HDD) platters.
Conclusions:
- The proposed imaging technique is effective for inspecting challenging manufactured surfaces.
- It offers a versatile solution for detecting diverse defect types in early production.
- This method enhances automated inspection capabilities for critical components.
