Cutting Tools and Fluids

Date: 2015-10-07; view: 439.

Grinders

Grinding is the removal of material by a rotating abrasive wheel. The wheel consists of many small particles of abrasive, connected together. Each particle acts as a miniature cutting tool. The process produces extremely smooth and accurate surfaces.

Because cutting processes include high local stresses, frictions, and heat generation, cutting-tool material must combine strength, toughness, hardness, and wear resistance at high temperatures. These requirements are met, in different degrees, by such cutting-tool materials as carbon steels, stainless steels, high-speed steels, tungsten carbide, and diamonds and by such recently developed materials as ceramic, carbide ceramic, and aluminum oxide.

In many cutting operations fluids are used to cool and lubricate. Cooling reduces friction, decreasing the heat generation, increases tool life and helps to stabilize the size of the finished part.

Задания к тексту A:

I. Прочитайте и переведите следующие выражения:

stationary power-driven machines; the manufacture of machine and tool parts; the unwanted portion in the form of chips; light, electrical, chemical, and sonic energy; high-energy particle beams; a turning machine; a cutting tool; to be moved parallel to or across the direction of rotation; to cut threads; flat surfaces; a single-point tool; for this reason; a production line; the reciprocating machine tools; a milling machine; a series of cutting edges on its circumference; hole-making machine tools; in accordance with; multispindle units; an abrasive wheel; heat generation; cutting-tool materials; carbon steels; high-speed steels; tungsten carbide; carbide ceramic.

II. Найдите в предыдущем упражнении английские эквиваленты следующих русских выражений:

станок возвратно-поступательного действия; лишний материал в виде стружки; в соответствии с; луч из высокоэнергетических частиц; фрезерный станок; режущий инструмент; значительная выработка тепла; карбидная керамика; материал для режущих инструментов; токарный станок; многошпиндельные устройства; плоские поверхности; стационарный электрические станки; углеродистые стали; производство деталей машин и инструментов; серия режущих лезвий по окружности (фрезы); однолезвийный инструмент; быстрорежущие стали; двигаться параллельно или поперек направлению вращения; карбид вольфрама; нарезать резьбу; абразивный (шлифовальный) круг; световая, электрическая, химическая и звуковая энергия; штампы и пробойники; станки просверливающие отверстия; по этой причине; вдоль или под прямыми углами к станине; производственная линия.

III. Прочитайте слова, вспомните как переводятся прилагательные с отрицательным префиксом. Дайте несколько своих примеров:

indirectly; unconventional; unwanted.

IV. Сделайте грамматический разбор предложения, определите тип придаточного предложения и поставьте предложение в будущее время:

1. Hole-making machine tools are used to drill a hole where none previously existed. 2. It is, however, essential in tool rooms and job shops when a few identical pieces are being made. 3. The tool can be moved parallel to or across the direction of rotation to form parts that have a cylindrical or conical shape or to cut threads.

V. Прочитайте предложение, сделайте грамматический разбор, измените залог на противоположный:

These requirements are met, in varying degrees, by such cutting-tool materials as carbon steels, high-speed steels, tungsten carbide, and diamonds and by such recently developed materials as ceramic, carbide ceramic, and aluminum oxide.

VI. Найдите в предложениях место для наречий образа действия, стоящих в скобках. Предложения переведите:

1. The shaper is used to produce flat surfaces. (primarily) 2. Machine tools form the basis of modern industry and are used in the manufacture of machine and tool parts. (either directly or indirectly) 3. It uses a single-point tool and is slow. (relatively) 4. For this reason, the shaper is found on a production line. (seldom) 5. In many cutting operations fluids are used to cool and lubricate. (successfully)

VII. Ответьте письменно на следующие вопросы:

1. What is a machine tool?

2. What are they usually used for?

3. How can machine tools be classified?

4. What are conventional machine tools?

5. What are unconventional machine tools?

6. How does a lathe work?

7. Why aren't shapers used on production line?

8. Where are shapers usually used and why?

9. What tool is used in a milling operation?

10. Are there different types of drilling machines?

11. Boring is a process that increases holes previously drilled, isn't it?

12. Is grinding performed by rotating a workpiece or an abrasive wheel?

13. Don't cutting processes include high local stresses, frictions, and heat generation?

14. What is used to reduce friction and increase tool life?

VIII. Переведите текст А письменно.