Comparative evaluation of the performances of single layer diamond tools in orbital drilling of composites

Abstract

Orbital drilling is an advanced and improved technique over conventional drilling in producing holes in composites. Single layer diamond tools of different geometries and grain sizes were experimentally investigated to explore their performances in orbital drilling of multidirectional carbon/epoxy laminates. The effects of diamond grain sizes, types of flutes and tool end geometries were evaluated in terms of drilling forces, temperatures, drilling-induced defects and surface integrity. It was found that drilling with high spindle rotational speed results in significantly reduced forces. Tools with smaller grain sizes improve hole surface roughness at the cost of increased drilling forces and temperatures. Provision of flutes on tools lowers the tendency of tool clogging. Ball end tools perform better than tools with flat end geometry and without flutes.

Keywords

• helical drilling
• cfrp
• single layer diamond tool
• drilling force
• temperature
• surface integrity