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Milling is the process of removing metal with rotating cutters.
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The essential features of most milling machines are a power-driven table on which the work is done and a spindle carrying one or more multiple-toothed cutters, slots or grooves.
The horizontal milling machine consists of a main casting in which the spindle and its gear drive and the gear-box are mounted. On the front of this casting is a vertical V-guide on which the knee is mounted. The knee is raised or lowered by a telescopic jack screw. A saddle slides from front to back on V-guides on the top of the knee. The work table is mounted in V-guides on the saddle. The table is provided with movement in two directions at right angles to each other in the horizontal plane, and with vertical movement relative to the cutter, whose height is permanently fixed.
The cutter is mounted on an arbor and held in the desired position by spacing washers and a locking nut.
The type of a cutter mainly used on the horizontal miller is what is known as a side and face cutter, that is, a cutter provided with cutting edges on both sides and on periphery. For large flat surfaces, roller milling cutters are used, having cutting edges in the form of helix about the axis of rotation.
II.Переведите на русский язык следующие английские словосочетания:
| 1) the process of removing metal | 6) the movement of the work |
| 2) a rotating multipoint cutter | 7) the number of spindle revolutions per minute |
| 3) relative to the cutting surface | 8) the essential features |
| 4) can be conventionally regarded | 9) multiple-toothed cutters; |
| 5) the rotation of a cutter | 10) the spindle is mounted |
III.Найдите в тексте английские эквиваленты следующих словосочетаний:
| 1) движение детали | 6) относительно режущей поверхности |
| 2) процесс удаления (снятия) металла | 7)вращающаяся многозубая фреза |
| 3) могут условно относиться | 8) суппорт скользит |
| 4) вращение фрезы | 9) процесс удаления металла |
| 5) число оборотов шпинделя в минуту | 10) характерные черты (особенности) |
IV.Найдите в тексте слова, имеющие общий корень с данными словами. Определите, к какой части речи они относятся, и переведите их на русский язык:
face, convention, cut, rotate, move, avail, permanent, mill, direct.
V.Задайте к выделенному в тексте предложению все типы вопросов: общий, альтернативный, разделительный, два специальных: а) к подлежащему, б) к любому члену предложения.
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VI.Выполните анализ данных предложений, обратив внимание на следующие грамматические явления: формы и функции причастия, независимый причастный оборот, формы и функции герундия, герундиальный оборот. инфинитивные конструкции (сложное дополнение, сложное подлежащее), существительное в роли определения, функции слов one (ones), that (those), условные предложения (сослагательное наклонение 1 и 2 типов):
1. Milling is the process of removing metal by feeding the work past a rotating multipoint cutter.
2. All cutters are said to be conventionally regarded as belonging to the above two main types.
3. The cutter is mounted on an arbor and held in the desired position by spacing washers and a locking nut.
4. For large flat surfaces, roller milling cutters are used, having cutting edges in the form of helix about the axis of rotation.
5. If the cutter were mounted on an arbor they would hold in the desired position by spacing washers and a locking nut.
VII.Ответьте на вопросы по тексту:
1. What is milling?
2. What are the essential features of most milling machines?
3. What does the horizontal milling machine consist of?
4. What is there on the front of the casting?
5. What is mounted on the casting?
6. What is the rotation of the cutter characterized by?
7. Where is the cutter mounted on?
VIII.Составьте аннотацию на текст (2-3 предложения).
IX.Составьте реферат на текст (10-15 предложений).
X. Составьте план текста и перескажите текст.
ВАРИАНТ № 11
I. Прочитайте и переведите тексты:
MAIN TYPES OF MILLING MACHINES
Milling machines are extremely versatile machine-tools. They can be used to machine flat and formed surfaces, to cut splines, teeth and threads and even to perform drilling and boring operations. Milling machines are an important part in all installed metal-cutting machines and their number is continuously increasing.
There are many types of milling machines, for example:
1. Column-and-Knee Type Milling Machine. This is the most extensively used type of milling machine.
2. Fixed-Bed and Planer-Type Milling Machine.
3. Continuous Action Machine.
4. Special Milling Machine. These machines are employed in the clock and watch industry, as well as in the automobile, tractor and machine-tool industry.
MILLING CUTTERS
The cutting element of any tool is wedge-shaped. The force applied to the tool causes its wedge to enter the material being cut, destroy the cohesion of its particles and push the separated layer aside.
The sharper the wedge, i.e., the smaller the angle formed by its sides, the less effort is required to feed it into the cut. The angle included between the sides of the wedge is called the “lip angle” and is denoted by the Greek letter beta. We can say, therefore, that the smaller the lip angle beta, the more easily the cutter will penetrate into the metal, and, conversely, the greater the lip angle, the greater the force that must be applied to remove the metal.
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Much depends on the material to be cut. If a hard material is to be cut with a tool having a small lip angle beta, the thin edge will be too weak and will either crumble or break.
Milling cutters with helical teeth provide much smoother performance. Cutter teeth may have either a left-hand or a right-hand helix. For ordinary milling, preference is given to right-hand helices. Milling cutters with a small number of teeth are employed for rough milling operations.
Conversely, cutters with a large number of teeth are used for finish milling operations.
II.Переведите на русский язык следующие английские словосочетания:
| 1) extremely versatile machine-tools | 6) causes the wedge to enter the material being cut |
| 2) to machine flat surfaces | 7) the angle formed by the sides |
| 3) to cut threads | 8) destroys the cohesion of particles |
| 4) to employ in boring operations | 9) to penetrate into the metal |
| 5) the force applied to the tool; | 10) to remove the metal |
III.Найдите в тексте английские эквиваленты следующих словосочетаний:
| 1) обрабатывать плоские поверхности | 6) сила, применяемая к инструменту |
| 2) применять в расточке | 7) угол, образованный его сторонами |
| 3) супер универсальные станки | 8) снимать метал |
| 4) нарезать резьбу | 9) разрушает сцепление частиц |
| 5) заставляет клинок входить в материал, который режут | 10) зависит от материала, который режут |
IV.Найдите в тексте слова, имеющие общий корень с данными словами. Определите, к какой части речи они относятся, и переведите их на русский язык:
extreme, continuous, extensive, act, cut, there, perform, prefer, operate, converse.
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