生命中，不断地有人离开或进入。于是，看见的，看不见的；记住的，遗忘了。生命中，不断地有得到和失落。于是，看不见的，看见了；遗忘的，记住了。然而，看不见的，是不是就等于不存在？记住的，是不是永远不会消逝？ 攀枝花学院本科毕业设计（论文）外文译文院 （系）： 机电工程学院 专 业： 机械设计制造及其自动化 姓 名： 王 中 蔚 学 号： ZJD02043 指导老师评语： 署名： 年 月 日外语文献翻译摘自: 《制造工程与技术（机加工）》（英文版） 《Manufacturing Engineering and Technology—Machining》 机械工业出版社 2025 年 3 月第 1 版 美 s. 卡尔帕基安(Serope kalpakjian) s.r 施密德(Steven R.Schmid) 著原文：20.9 MACHINABILITYThe machinability of a material usually defined in terms of four factors:1、Surface finish and integrity of the machined part;2、Tool life obtained;3、Force and power requirements;4、Chip control. Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone.Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.20.9.1 Machinability Of SteelsBecause steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels.Resulfurized and Rephosphorize...
