Lesson 31 Mechanism of Surface Finish Production 机械工程专业英语 教学课件.pptVIP

English for Mechanical Engineering 机械工程专业英语 表面光洁度的形成： 几何原因：主要是刀具的形状和角度，特别是刀尖圆角半径和主、副偏角，其次是进给量和刀刃本身的粗糙度 物理原因 积屑瘤的产生、长大和脱落 鳞刺的产生：抹拭---导裂---层积---刮成 薄层切削时的打滑、刀具后刀面的摩擦、挤压和回弹，划痕 脆性材料：碎裂，造成崩裂切屑 切削时的振动：自由振动、强迫振动和自激振动 刀具的几何角度 built-up–edge 积屑瘤 rake angle 前角 relief angle 后角 face 前刀面 flank 后刀面 chatter 刀振 major-cutting-edge(end-cutting-edge) 主切削刃 minor-cutting-edge(side -cutting-edge) 副切削刃 chatter 刀振 end-cutting-angle 主偏角 nose angle 刀尖圆角 side -cutting-angle 副偏角 * * 常州工学院机电工程学院 徐红丽 机械工程专业英语 预备知识 一、预备知识 Lesson 31 Mechanism of Surface Finish Production 词 汇 二、词汇 机械工程专业英语 Lesson 31 Mechanism of Surface Finish Production 机械工程专业英语 There are basically five mechanisms which contribute to the production of a surface which have been machined.These are: 课文分析 三、课文分析 对已加工表面的表面粗糙度的形成基本上有五个方面机理，它们是： Lesson 31 Mechanism of Surface Finish Production 机械工程专业英语 （1）The basic geometry of the cutting process.In, for example,single point turning， the tool will advance a constant distance axially per revolution of the workpiece and the resultant surface will have on it when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut. 课文分析 1)切削过程的基本几何形状。例如在单刃车削加工中，工件每转一转车刀将沿轴向进给一固定的距离即获得被加工面。从垂直于刀具进给方向观察时，结果在工件表面上有一系列尖角，基本形状就是复制了切割刀具刀尖的形状． Lesson 31 Mechanism of Surface Finish Production 机械工程专业英语 课文分析 Lesson 31 Mechanism of Surface Finish Production （2）The efficiency of the cutting operation. It has already been mentioned that cutting with unstabel built-up—edges will produce a surface which contains hard built-up-edges fragments which will result in a degradation of the surface finish. 切削加工的效果．已经论述过，用不稳定切屑瘤的切削加工会产生含有硬切屑瘤碎屑的表面，这些碎屑将导致表面光洁度的降低。 机械工程专业英语 It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds, small rake angles and low cutting speeds, besides producing conditions which lead to unstable