Digital image correlation utilization in measuring displacement and strain during plastic film blowing process: A feasibility study

Abstract This research work explores on Digital Image Correlation (DIC) technique as a potential tool for measuring displacement and strain in film blowing extrusion process. A feasibility study on the surface patterning technique, validation of the DIC analysis and selection of DIC parameters were investigated. Understanding on the effects of these factors on the analysis of DIC in film blowing process is crucial as the film moves vertically at a relative speed while being stretched and deformed. Results showed that ink application was the best practice for surface pattern creation. The DIC was validated as a reliable method as the results obtained with the ink procedure were comparable to the conventional grid method. Subset size of 11 pixels and 21 pixels were preferred for small and large pattern, respectively. Regardless of pattern size, subset space of 1 pixel and strain radius of 5 pixels was chosen for yielding accurate result without any distortion in spatial resolution.