Most of the mechanical operations are commonly performed on five basic machine tools:

1. The drill press.

2. The lathe.

3. The shaper of planer.

4. The milling machine.

5. The grinder.

Drilling

Drilling is performed with a rotating tool called a drill. Most drilling in metal is done with a twist drill. The machine used for drilling is called a drill press. Operations, such as reaming and tapping, are also classified as drilling. Reaming consists of removing a small amount of metal from a hole already drilled. Tapping is the process of cutting a thread inside a hole so that a cap screw or bolt may be threaded into it.

Turing and Boring

The lathe is commonly called the father of the entire machine tool family. For turning operations, the lathe uses a single-point cutting tool which removes metal as it travels past the revolving workpiece. Turning operations are required to make many different cylindrical shapes, such as axes, gear blanks, pulleys, and threaded shafts. Boring operations are performed to enlarge, finish, and accurately locate holes.

Milling

Minning removes metal with a revolving, multiple cutting edge tool called milling cutter. Milling cutters are made in many styles and sizes. Some have as few as two cutting edges and others have 30or more. Milling can produce flat or angled surfaces, groves, slots, gear teeth, and other profiles, depending on the shape of the cutters being used.

Shaping and Planing

Shaping and planning produce flat surfaces with a single-point cutting tool. In shaping, the cutting tool on a shaper reciprocates or moves back and forth while the work is fed automatically towards the tool. In planning, the workpiece is attached to a worktable that reciprocates past the cutting tool. The cutting tool is automatically fed into the workpiece a small amount on each stroke.

Grinding

Grinding makes use of abrasive particles to the cutting. Grinding operations may be classified as precision or nonprecision, depending on the purpose. Precision grinding is concerned with grinding to close tolerances and very smooth finish. Nonprecision grinding involves the removal of metal where accuracy is not important .

Vocabulary

drill n. a tool for making holes in metal, wood, etc.

v. to make a hole with a drill

lathe n, a machine for shaping a piece of metal or wood by holding and turning it

against the edge of a cutting tool 车床

shaper n. 牛头刨床

planer n. 龙门刨床

mill n. 铣床

grinder n. 磨床

rotate v. move round about its own center; turn in a circle

twist n. turning

press n. a device used for acting on with steady force or weight

ream v. 铰孔

tap v. 攻丝

classify vt. arrange in groups and classes

screw n. 螺钉

bolt n. 螺栓

cylindrical adj. having a shape like a cylinder, such as a pipe

axis n. 轴

gear n. 齿轮

blank n. a piece of metal to be cut or machined with a design

pulley n. 滑轮

shaft n. 螺杆

bore v. 镗削

groove n. 槽

slot n. 缝

profile n. an outline

reciprocate vi. move backwards and forwards

abrasive adj. 摩擦的,磨损的

tolerance n. the amount of variation allowed from a standard, accuracy, etc. 公差

turn v. 车削

finish v. 修整,精加工

Phrases and Expressions

be classified as 归类为

back and forth 来回

be attached to 与

feed…into 把……送进