基本的加工工序—切削，镗削和铣削

中文译文
基本的加工工序—切削，镗削和铣削(中文4500字,英文3100字)
机床是从早期的埃及人的脚踏动力车床和约翰.威尔金森的镗床发展而来的。它们用于为工件和刀具两者提供刚性支撑并且可以精确控制它们的相对位置和相对速度。一般来说，在金属切削中用一个磨尖的楔形工具以紧凑螺纹形的切屑形式从有韧性工件表面上去除一条很窄的金属。切屑是废弃的产品，与其工件相比，它相当短但是比未切削的部分厚度有相对的增加。机器表面的几何形状取决于刀具的形状以及加工过程中刀具的路径。
不同的加工工序生产出不同几何形状的部件。如果一个粗糙的柱形工件绕中心轴旋转而且刀具穿透工件表面并沿与旋转中心平行的方向前进，就会产生一个旋转面，这道工序叫车削。如果以类似的方式加工一根空心管的内部，则这道工序就叫镗削。制造一个直径均匀变化的锥形外表面叫做锥体车削。如果刀具尖端以一条半径可变的路径前进，就可以制造出象保龄球杆那种仿形表面；如果工件足够短而且支撑具有足够的刚性，仿形表面可以通过用一个垂直于旋转轴的仿形刀具来制造。短的锥面或柱面也可以仿形切削。

英文原文
Basic Machining Operations
Machining tools have evolved from the early foot –powered lathe Egyptians and John Wilkinson’s boring mill. They are designed to provide rigid support for both the workpiece and the cutting tool and cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the from of a severely deformed chip. The chip is waste product that is workpiece in the from of a severely deformed chip is a waste product that is considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of the machine surface depends on the shape of the tool and its path during the machining opration.
Most machine operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is on the machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface of uniformly varying diameter is called taper turning. If the tool point travels in a path of varying radius, a contoured surface like that of bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed.