Modelling of surface evolution in abrasive jet micro-machining including particle second strikes: A level set methodology

A previous implementation of narrow band level set methodology for the modelling of the surface evolution of masked features in abrasive jet micro-machining (AJM) including the effect of mask erosive wear was extended to include the effect of particle second strikes. The model uses a ray tracing/node tracking algorithm to allow the prediction of the effect of particle ricochets from the mask edges and the sidewalls of the machined feature on the resulting surface evolution of high aspect ratio features. Using the model, for the first time, the prediction of the particle second strike effects from inclined masked features is made possible. When compared to previous models that did not account for mask wear and second strike effects, the present model significantly improved the prediction of measured masked micro-channels machined using AJM in glass. When compared to previous particle tracking computer simulations, the present model was found to have a much shorter execution time, and in some cases also showed an improved prediction. The model can be useful in predicting the feature shape in the AJM of brittle targets for aspect ratios greater than 1, and hence for the micro-fabrication of microfluidic and MEMS devices.

► An abrasive jet micro-machined feature predictive level set based model is extended. ► It is the first to predict particle second strikes in inclined masked features. ► It showed improvement in feature prediction or execution speed over previous models. ► It can be used to predict the shape of high-aspect ratio brittle features. ► Second strikes off the mask can be ignored.