Text С: «MILLING MACHINE»

In a milling machine thecutter (фреза) is a circular device witha series of cuttingedges on itscircumference. The workpiece is held on a table that controls the feed against the cutter. The table has three possible movements:longitudinal, horizontal, andvertical; in some cases it can also rotate. Milling machines are the mostversatile of all machine tools.Flat or contouredsurfaces may be machined with excellent finish and accuracy.Angles, slots, gear teeth and cuts can be made by using various shapes of cutters.

Drilling and Boring Machines

To drillahole usually hole-making machine-tools are used. They can drill a hole according to some specification, they canenlarge it, or they can cut threads for a screw or to create an accurate size or a smooth finish of a hole.

Drilling machines (сверлильные станки) are different in size and function, fromportable drills to radial drilling machines, multispindleunits, automatic production machines, and deep-hole-drilling machines.

Boring (расточка) is a process that enlarges holespreviously drilled, usually with a rotating single-point cutter held on a boring bar and fed against a stationary workpiece.

Shapers and Planers

The shaper (поперечно-строгальный станок) is used mainly to produce different flat surfaces. The toolslidesagainst the stationary workpiece and cuts on onestroke,returns to its starting position, and then cuts on the next stroke after a slightlateral displacement. In general, the shaper can make any surface havingstraight-line elements. It uses only one cutting-tool and is relatively slow, because the return stroke isidle. That is why the shaper is seldom found on a mass production line. It is, however, valuable for tool production and forworkshops where flexibility is important and relative slowness is unimportant.

Theplaner (продольно-строгальный станок) is the largest of the reciprocating machine tools. It differs from the shaper, which moves a tool past a fixed workpiece because the planer moves the workpiece to expose a new section to the tool. Like the shaper, the planer is intended to produce vertical, horizontal, or diagonal cuts. It is also possible tomount several tools at one time in any or all toolholders of a planer toexecute multiple simultaneous cuts.

Grinders

Grinders (шлифовальные станки)remove metal by a rotating abrasivewheel. The wheel is composed of many small grains of abrasive,bonded together, with each grain acting as a miniature cutting tool. The process gives very smooth and accurate finishes. Only a small amount of material isremoved at eachpass of the wheel, so grinding machines requirefine wheel regulation. The pressure of the wheel against the workpiece is usually very light, so that grinding can be carried out onfragile materials that cannot be machined by otherconventional devices.

Vocabulary:

milling machine —фрезерный станок

series — серия, ряд

cutting edge — режущий край, острие

circumference — окружность

to feed— подавать

longitudinal— продольный

horizontal — горизонтальный

vertical — вертикальный

versatile — универсальный

flat— плоский

contoured — контурный

angle— угол

slot — прорезь, паз

gear teeth— зубья шестерни

drill — дрель, сверло, сверлить

hole — отверстие

to enlarge— увеличивать

thread— резьба

portable— портативный

unit— единица, целое, узел

previously — ранее

to slide — скользить

stroke— ход

lateral — боковой

displacement— смещение

straight— прямой

idle— на холостом ходу

workshop — цех, мастерская

to mount — крепить

holder — держатель

to execute— выполнять

simultaneous — одновременный

multiple — многочисленный

grinder— шлифовальный станок

wheel — круг, колесо

bonded — скрепленный

to remove — удалять

pass— проход

fine — точный

conventional — обычный

device — устройство, прибор

fragile — хрупкий

General understanding:

1. What is the shape of a cutter in a milling machine?

2. What moves in a milling machine, a table or a cutter?

3. What possible movements has the table of a milling machine?

4. What kind of surfaces and shapes may be machined by a milling machine?

5. What can we use a drilling machine for?

6. What kinds of drilling machines exist?

7. What is rotated while boring, a cutter or a work-piece?

8. Describe the work of a shaper (planer).

9. What must be done to execute multiple simultaneous cuts on a planer?

10. What is the working tool in a grinder?

11. Can we obtain a very smooth surface after grinding and why? 12. Can we grind fragile materials and why?

Exercise 4.3. Translate into English:

1. Токарный станок все еще остается самым важным станком.

2. Все современные токарные станки оборудованы электроприводами.

3. Движение инструмента контролируется с высокой точностью.

4. Электропривод позволяет обрабатывать заготовку на различных скоростях.

Text D: «DIES»

Dies are tools used for the shaping solid materials, especially those employed in the pressworking of cold metals.

In presswork, dies are used in pairs. The smaller die, orpunch, fits inside the larger die, called thematrix or, simply, the die. The metal to be formed, usually a sheet, is placed over the matrix on the press. The punch is mounted on the press and moves down by hydraulic or mechanical force.

A number of different forms of dies areemployed for different operations. The simplest arepiercing dies(пробивной штамп), used forpunching holes. Bending and folding diesare designed to make single or compound bends. A combination die is designed to perform more than one of the above operations in one stroke of the press. A progressive die permits successive forming operations with the same die.

In coining, metal is forced to flow into twomatchingdies, each of which bears a engraved design.

Wiredrawing Dies

In the manufacture ofwire, a drawplate (волочильная доска) is usuallyemployed. This tool is a metal plate containing a number of holes, successively less in diameter and known as wire dies. A piece of metal is pulled through the largest die to make acoarse wire. This wire is then drawn through the smaller hole, and then the next, until the wire is reduced to the desired measurement. Wiredrawing dies are made from extremely hard materials, such as tungsten carbide or diamonds.

Thread-Cutting Dies

For cuttingthreads on bolts or on the outside of pipes, a thread-cutting die (резьбонарезная плашка) is used. It is usually made ofhardened steel in the form of a round plate with a hole in the centre. The hole has a thread. To cut anoutside thread, the die islubricated with oil and simplyscrewed onto an unthreaded bolt or piece of pipe, the same way anut is screwed onto a bolt. The corresponding tool for cutting aninside thread, such as that inside anut, is called atap (метчик).

Vocabulary:

chip— стружка

sharp — острый

friction — трение

content — содержание

range — диапазон

inexpensive — недорогой

to permit — позволять, разрешать

common — обычный

tungsten — вольфрам

ingredient — ингредиент

diamond — алмаз