Development of a BDD end-grinding-milling tool with dual-negative rake angle

Shun Tong Chen*, Wei Jen Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Due 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 tool’s 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.

Original languageEnglish
JournalMaterials and Manufacturing Processes
Publication statusAccepted/In press - 2023


  • Dual-negative rake angle
  • across-center cutting edge
  • end-grinding-milling tool
  • pressure-cutting force

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering


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