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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

tips — наконечники

ceramic — керамический

truing — правка, наводка, заточка

die — матрица, штамп

matrix — матрица

to employ — применять

to pierce — протыкать, прокалывать

to punch — пробивать отверстие

matching — сочетающийся, парный

coarse — грубый

wire — проволока

to draw — тащить, волочить

thread — резьба

hardened — закаленный

to lubricate — смазывать

to screw — привинчивать

nut — гайка

outside — наружный, внешний

inside — внутри, внутренний


Exercise 4.4. Find English equivalents in the text:


1. удалять металлическую стружку

2. острый режущий край

3. содержание углерода

4. режущая способность

5. сталь для скоростного резания

6. правка шлифовальных кругов

7. гидравлическое или механическое давление

8. различные формы штампов


 

Exercise 4.5. Translate the following sentences into Russian:

1. Все резцы и фрезы должны иметь острую режу­щую кромку.

2. Во время резания режущий инструмент и деталь имеют высокую температуру и должны охлаждаться.

3. Углеродистые стали часто используются для из­готовления резцов потому, что они недорогие.

4. Быстрорежущие стали содержат вольфрам, хром и ванадий.

5. Алмазы используются для резания абразивных материалов и чистовой обработки поверхности твер­дых материалов.

6. Для различных операций используют различные штампы.

7. Волочильные доски для проволоки делаются из очень твердых материалов.

8. Резьбонарезные плашки и метчики используют­ся для нарезки резьбы снаружи и внутри.

FAMOUS PEOPLE OF SCIENCE AND ENGINEERING

George Stephenson

George Stephenson was a British inventor and engi­neer. He is famous for building the first practical rail­way locomotive.

Stephenson was born in 1781 in Wylam, near New­castle upon Tyne, Northumberland. During his youth he worked as a fireman and later as an engineer in the coal mines of Newcastle. He invented one of the first miner's safety lamps independently of the British inventor Humphry Davy. Stephenson's early locomotives were used to carry loads in coal mines, and in 1823 he estab­lished a factory at Newcastle for their manufacture. In 1829 he designed a locomotive known as the Rocket, which could carry both loads and passengers at a greater speed than any locomotive constructed at that time. The success of the Rocket was the beginning of the construc­tion of locomotives and the laying of railway lines.

Robert Stephenson, the son of George Stephenson was a British civil engineer. He is mostly well-known known for the construction of several notable bridges.

He was born in 1803 in Willington Quay, near New­castle upon Tyne, and educated in Newcastle and at the University of Edinburgh. In 1829 he assisted his father in constructing a locomotive known as the Rocket, and four years later he was appointed construction engineer of the Birmingham and London Railway, completed in 1838. Stephenson built several famous bridges, includ­ing the Victoria Bridge in Northumberland, the Britan­nia Bridge in Wales, two bridges across the Nile in Damietta in Egypt and the Victoria Bridge in Montreal, Canada. Stephenson was a Member of Parliament from 1847 until his death in 1859.

 

 

UNIT 8

PLASTICS





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