Development of a BDD end-grinding-milling tool with dual-negative rake angle
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2023-12-04 |
| Journal | Materials and Manufacturing Processes |
| Authors | Shun-Tong Chen, WeiāJen Huang |
| Institutions | National Taiwan Normal University |
| Citations | 1 |
Abstract
Section titled āAbstractāDue to its high melting point, tungsten carbide is perfect for mold-core usage during glass molding processes (GMP) such as those needed for manufacturing aspheric lenses. However, its extreme hardness makes it exceedingly difficult to machine. To overcome this problem, a BDD (boron-doped diamond) end-grinding-milling tool with dual-negative rake angle is designed and applied in this study to effectively mill a tungsten-carbide substrate. The first negative rake angle, with cutting edge across the toolās centerline, prevents squashing during cutting between tool point and mold-core surface. This suppresses brittle fracturing by cutting material under pressure-cutting force in the machining area. Further, when preparing the cutting tool, micro w-EDM was used to create micro-protrusion abrasives on the plane of the first negative rake angle that feature a different second negative rake angle, providing pressure in all directions during material removal. This feature ensured cutting occurred under a non-tensile-stress regime, which avoided microcracks and subsurface damage. Experiments have shown that the developed end-grinding-milling tool was successful in creating micro-flutes and an aspheric lens mold-core array. Surface roughness was nano-scale and there were no burrs nor chipping along mold edges, indicating the designed BDD end-grinding-milling tool is good for grinding-milling of superhard materials.