Reliability Of High-speed Steel Cone Cryogenic Life

Tool life reliability is a very important indicator to cutting tool, it weregiven more and more attention at present. The life reliability of cryogenic highspeed steel tap cutting H13steel be studied in the paper based on the study ofthe reliability of the tool life.Researches focus on the followings:(1) At first, the Taylor tool life basic equation is extended. Eeneralizedequation of tool life extension equation is proposed and is applied in a narrowrange. The relationship between tap wear and tap main cutting geometryparameters is established. So the theoretical basis for the analysis of affectingfactors of cryogenic high speed steel tap life and the evaluation of reliability inthis paper is provides.(2) The life reliability experiment of cutting H13was carried out in afixed cutting condition. Statistical analysis and parametric test of tap geometricparameters are executed and the distribution of tap geometry parameters isanalyzed. Tapping experiment is executed and the tool wear form is observed.The cryogenic high speed steel tap wear mechanism is analyzed.(3) The cryogenic high speed steel tap wear process is modeled by aGamma process and the parameters is estimated. In the small sample andwithout failure data, the tap life reliability prediction models of two cases areestablished. A kind of circumstance, the tap manufacturing erroris consideredand another case the tap manufacturing error is not took into account. Thesensitivity of each parameter of the reliability model is be analyzed. The mainfactor to affect tap life reliability is manufacturing error of tap and themaximum permissible machining error of the machine tool, so it’s researched.(4) The relationship equation of cryogenic high speed steel tap life withits geometry parameters is solved by multiple linear regression. The influenceto tap wear of the clearance angle, the cutting edge angle, and the rake angle isestablished.The dispersibility of tap norm wear is studied and the tap life becalculated according to the wear patterns. Cryogenic high speed steel tap life calculated by the maximum amount of wear obeys normal distribution. Lifereliability evaluation models for the cryogenic high speed steel tap wear formsare established based on tap life extension equation, and life reliability of tap isevaluated.The influence factors of cryogenic high speed steel tap reliability areanalyzed.The research was supported by the National Science Foundation underGrant No.51275333.