TY - JOUR
T1 - Development of a BDD end-grinding-milling tool with dual-negative rake angle
AU - Chen, Shun Tong
AU - Huang, Wei Jen
N1 - Publisher Copyright:
© 2023 Taylor & Francis.
PY - 2024
Y1 - 2024
N2 - 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.
AB - 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.
KW - Dual-negative rake angle
KW - across-center cutting edge
KW - end-grinding-milling tool
KW - pressure-cutting force
UR - http://www.scopus.com/inward/record.url?scp=85178451371&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85178451371&partnerID=8YFLogxK
U2 - 10.1080/10426914.2023.2290236
DO - 10.1080/10426914.2023.2290236
M3 - Article
AN - SCOPUS:85178451371
SN - 1042-6914
VL - 39
SP - 938
EP - 948
JO - Materials and Manufacturing Processes
JF - Materials and Manufacturing Processes
IS - 7
ER -