High-Speed Finishing of Hard Gear Teeth with cBN-Tipped Hob

Abstract

The hobbing finish of hard gear teeth such as case-hardened gears is anticipated for practical use in high efficiency production. We studied wear and finished surface properties in cutting tests using a cubic boron nitride (cBN) hob cutter in high-speed cutting at 900 m/min of case-hardened steel. The cBN content in tip ingredients is related to wear, and tips high in cBN content are superior in wear resistance. The high thermal conductivity of cBN tips helps transfer cutting temperature heat to chips, melting and adhering them to the relief surface. Flaking may occur on the cutting edge but new chipping does not occur although chipping may exist after grinding. Finished surface roughness is influenced by horning on the cutting edge. Round horning leads to a smooth surface. High-speed finishing with cBN-tipped hobs is analyzed in view of cBN tip grinding and finished surface properties, in addition to wear properties.

Power Transmissions

“…In gear hobbing, there are many tools that can be used effectively as mentioned by Ariura et al (1989), Sakuragi et al (2001) and Umezaki et al (2008). Particurarly, High Speed Steel (HSS) hob is one of the most useful tools.…”

“…Particurarly, High Speed Steel (HSS) hob is one of the most useful tools. Furthermore, the cutting mechanics in gear hobbing is very complex as mentioned by Umezaki et al (2001Umezaki et al ( , 2008 and Ishimaru et al (2011). Therefore, it is important that improving productivity for gear manufacturing is increased by using carbide tipped hob with heatproof.…”