Study on the formation mechanism and morphology of edge burrs in radial fly-cutting of triangular pyramid microstructures

The triangular pyramid microstructures (TPM) have been widely applied in the optical field due to its excellent optical properties, such as refraction and reflection. However, the burrs generated during radial fly-cutting (RFC) will have an adverse effect on product performance. To address this issue, the formation mechanism of edge burrs in TPM is deeply analyzed, and RFC experiments are carried out. By adopting the orthogonal experimental method, the influence of processing parameters on the morphology and size of the edge exit burrs is systematically studied. The results indicate that the formation of edge exit burrs is caused by the plastic lateral flow phenomenon of the material in this region. Additionally, the adhesion of chips that have not been promptly separated from the workpiece further increases burr size. The edge exit burrs can be classified into four types: flaky curled burrs, blocky burrs, slim strip burrs, and filiform (thread-like) burrs. As for the two experimental indicators of the edge exit burr projection area and thickness, the main and secondary influencing factors are cutting depth, fly-cutting speed and feed speed. The projection area and thickness of the burrs decrease with the increase of fly-cutting speed, while they increase with higher feed speeds and finer cutting depths. Based on these findings, the optimized processing parameters are determined as follows: fly-cutting speed of 16.76 m/s, feed speed of 10 mm/min, and fine cutting depth of 2 μm. This study provides valuable insights for minimizing burrs and optimizing subsequent deburring processes.