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Drilling and Boring Machines
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To drill a hole usually hole-making machine-tools are used. They can drill a hole according to some specification, they can enlarge 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, from portable drills to radial drilling machines, multispindle units, automatic production machines, and deep-hole-drilling machines.
Boring (расточка) is a process that enlarges holes previously 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 tool slides against the stationary workpiece and cuts on one stroke, returns to its starting position, and then cuts on the next stroke after a slight lateral displacement. In general, the shaper can make any surface having straight-line elements. It uses only one cutting-tool and is relatively slow, because the return stroke is idle. That is why the shaper is seldom found on a mass production line. It is, however, valuable for tool production and for workshops where flexibility is important and relative slowness is unimportant.
The planer (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 to mount several tools at one time in any or all tool holders of a planer to execute multiple simultaneous cuts.
Grinders
Grinders (шлифовальные станки) remove metal by a rotating abrasive wheel. 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 is removed at each pass of the wheel, so grinding machines require fine wheel regulation. The pressure of the wheel against the workpiece is usually very light, so that grinding can be carried out on fragile materials that cannot be machined by other conventional 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
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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, or punch, fits inside the larger die, called the matrix 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 are employed for different operations. The simplest are piercing dies (пробивной штамп), used for punching holes. Bending and folding dies are 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 two matching dies, each of which bears a engraved design.
Wiredrawing Dies
In the manufacture of wire, a drawplate (волочильная доска) is usually employed. 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 a coarse 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.
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Thread-Cutting Dies
For cutting threads on bolts or on the outside of pipes, a thread-cutting die (резьбонарезная плашка) is used. It is usually made of hardened steel in the form of a round plate with a hole in the centre. The hole has a thread. To cut an outside thread, the die is lubricated with oil and simply screwed onto an unthreaded bolt or piece of pipe, the same way a nut is screwed onto a bolt. The corresponding tool for cutting an inside thread, such as that inside a nut, is called a tap (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.
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