【正文】 gear drive noise is lower, thus causes to the hard gear demand, also gave the gear manufacturer to propose explored the gear to process the new method the request Outline Uses in the power drive gear and the gear box, its size request smaller, the gear drive noise is lower, thus causes to the hard gear demand, also gave the gear manufacturer to propose explored the gear to process the new method the request. The gear in the hard heat treatment process, its material organization and the stress change, usually can cause the gear to have the distortion, namely tooth profile, tooth to and tooth pitch error. This this error will cause the tooth profile not correctly to mesh in the transmission time, thus has enlarged the load, will have the gear noise. Therefore, the hard gear after the heat treatment, should increase together the precision work working procedure generally. The hard gear precision work craft may divide into two kinds: A kind is uses non formed the cutting edge, like the gear rubs truncates the processing。 Another kind then is has formed the cutting edge like hard gear (HRC48 ~ 53) to roll truncates the processing. This article strongly will discuss will use in hardly rolling the hard alloy tools forming cutting edge precision work process which the tooth will process. The now hard alloy material, the cutting tool coating and the gearhobbing machine technology development, has caused the hard gear to roll cuts the processing technology to have the remarkable enhancement, specially is smaller than in the processing or was equal to when 12DP center small modulus gear, may withstand the enormous cutting force which in the hard cutting process produces. Hard alloy hob selection The hard alloy hob has the very big progress in the material variety specification. Superfine, is thin, medium or the big pellet hard alloy now all has the product. In addition, the hard alloy hob semifinished materials formed craft technology also had the remarkable enhancement, like uses static pressure and so on heat (HIP) the craft, this craft under the highpressured high temperature, increased the hard alloy semifinished materials intrinsic binding force, enhanced the hard alloy anti curved intensity. According to the ISO stipulation, the entity hard alloy material may differently divide into certain kinds according to the application situation: The gear cutting tool divides into K kind and P kind, K kind of hard alloy has a higher resistance to wear, P kind then has the better high temperature red hardness. In the K trademark and in the P trademark hard alloy, each kind of trademark hard alloy granular structure is different, from medium pellet to superfine pellet. Each kind of trademark all has its application situation, this is and the granular structure is connected. Generally speaking, regarding softly rolls truncates, the K analogy P kind of performance is friends with, K kind of hard alloy can obtain a micron level the granular structure (granularity to be smaller than mu m), but P kind then is not good. In abrasion aspect, K kind of toughness better, the life is longer. The hob resharpens and renovates After the hob processing certain quantity work piece, its cutting edge