(论文翻译 页数:6 字数:3898)像车床加工零件一样，镗床能在中空的工件或由钻削加工或其它工艺所加工的孔上进行内轮廓圆的加工。镗削是由那些类似车削的刀具完成的。因为镗头必须达到镗杆的全长，刀具将发生弯曲，因此，尺寸精度的保持性成为了一个重大问题。
镗杆必须有足够的刚度——刀杆是由较高弹性模量的材料制造的，比如碳化钨（硬质合金）——减小弯曲和避免摇动和振动。镗杆被设计有减振的能力。
镗床既能加工在车床上加工的较小工件，镗铣床又能加工巨大的工件。这类机械既有立式的又有卧式的并且能够完成如：车削、车端面、切槽、和倒角。一台立式的镗床类似一台车床，但它有一根垂直的工件旋转轴。
刀具（通常用于切削的单独切削点是由M-2和M-3高速钢和C-8硬质合金制造的）被安装于能垂直运动（用于镗削和车削）和径向运动（用于车端面）并由十字导轨导向的刀头上。刀头能够旋转加工圆锥形表面。
在卧式镗床上工件被装夹在能在水平面内两个轴向和径向上移动的工作台上，刀具被安装于能做垂直和纵向两方向上运动的主轴箱上。钻头、铰刀、螺纹刀和铣刀都能安装于机床主轴上。
镗床具有许多优良的性能，它所加工工件的直径是1m-4m(3ft-12ft)，工件尺寸达到20m(60ft)的可在专用的立式镗床上加工。机床功率范围可达到150kw(200hp)。这些可用于所有运动都能编程的数字控制加工。利用这些控制，只需要很少的相关作，并且稳定性和生产率大大提高了。镗床的切削速度和进给速度和车床比较相似。
坐标镗床是属于具有较高精度支撑的立式镗床。尽管它们可用于各类尺寸的工件加工和拥有夹紧合安装的刀具空间。它们正被多功能的数控机床取代。
镗床的设计要求：导轨的效率，类似于车削的经济型作，另外，应该考虑以下因素：
a.无论何时，应尽可能注意是加工通孔而并盲孔。（盲孔系列是指那些没有穿国工件厚度的孔）
(一)BORING AND BORING MACHINES
As carried out on a lathe, boring produces circular internal profiles in hollow work-pieces or on a hole made by drilling or another process, Boring is done with cutting tools that are similar to those used in turning. Because the boring bar has to reach the full length of the bore, tool deflection and, therefore, maintainance of dimensional accuracy can be a significant problem.
The boring bar must be sufficiently stiff—that is, made of a material with high elastic modulus, such as tungsten carbide –to minimize deflection and avoid vibration and chatter. Boring bars have been designed with capabilities for damping vibration.
Although boring operations on relatively small work-pieces. Can be carried out on a lathe, boring mills are used for large work-pieces. These machines are either vertical or horizontal, and are capable of performing operations such as turning, facing, grooving, and chamfering. A vertical boring machine is similar to a lathe but has a vertical axis of work-piece rotation.
The cutting tool (usually a single point made of M-2 and M-3 high-speed steel and C-7 and C-8 carbide) is mounted on the tool head, which is capable of vertical movement (for boring and turning) and radial movement (for facing), guided by the cross-rail. The head can be swiveled to produce conical (tapered) surfaces.
In horizontal boring machine, the work-piece is mounted on a table that can move horizontally in both the axial and radial directions. The cutting tool is mounted on a spindle that rotates in the headstock, which is capable of both vertical and longitudinal movements. Drills, reamer, taps, and milling cutters can also be mounted on the machine spindle.
b.应该控制径向进给速率，很难支撑径向，因为切削力引起镗杆的弯曲变形。
c.应该避免交叉的内表面加工。
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