LetterResidual stress measurement for injection molded components

- Low birefringence polariscope (LBP) of higher resolution, accuracy, and precision.
- Calibration for residual stress of injection molded and 3D printed optics.
- Useful for characterization and quality testing in optics and lithography.
- Non-destructive residual stress quantification of wavelength dependent material.
- Comparison of commercial system with research oriented system.

Residual stress induced during manufacturing of injection molded components such as polymethyl methacrylate (PMMA) affects the mechanical and optical properties of these components. These residual stresses can be visualized and quantified by measuring their birefringence. In this paper, a low birefringence polariscope (LBP) is used to measure the whole-field residual stress distribution of these injection molded specimens. Detailed analytical and experimental study is conducted to quantify the residual stress measurement in these materials. A commercial birefringence measurement system was used to validate the results obtained to our measurement system. This study can help in material diagnosis for quality and manufacturing purpose and be useful for understanding of residual stress in imaging or other applications.