Exercises. I. Use the following words and phrases in sentences of your own:

I. Use the following words and phrases in sentences of your own:

cutter, milling machine, column, knee, cutting fluid, power feed, fine feed, to swivel, pump, to house, elevating screw, to adjust, to clamp, overarm, feed rate

II. Answer the following questions:

1. What is milling? 2. What are the main types of milling machines? 3. How are column- and knee-type milling machines classified? 4. What does the base of the plain milling machine serve for? 5. By what, means can the cutting fluid flow be regulated? 6. What is located in the lower part of the column? 7. What is housed in the upper part of the column? 8. What can you say about the spindle of the

horizontal plain milling machine? 9. What is secured to the top of the column? 10. What is supported by the knee? 11. By what means can the knee be moved up and down? 12. Why should the knee be clamped either to the column or to the overarm during each milling operation?

III. Find in the text antonyms of the following words:

to raise, light, to be unfixed, fine feed, back, lower part

IV. Underline the suffixes and prefixes and translate into Russian the following words:

principle, principal; long, longitudinal; horizon, horizontal; to obtain, obtainable; automatic, automatical, automatically; to cut, cutting, non-cutting; convention, conventional; depend6nt, dependently, independently

V. State the kind of the subordinate clauses in the following sentences and translate them into Russian:

1. The profile of the teeth on the pinion is identical with the straight line profile of the teeth of a rack that meshes with the generated gear. 2. In the same way as one and the same rack will mesh with gears of different pitch diameters (number of teeth), but of identical diametral pitch, one and the same hob can be used to hob all gears of identical diametral pitch regardless of the number of teeth on the gears being hobbed. 3. The fact that the hob form nearly approaches a straight line rack tooth shape is a fundamental advantage of the hobbing process, because the hob teeth being straight-sided or nearly so, are readily made to a high degree of accuracy and are easily measured, as compared with curved cutter teeth in other methods of gear cutting.

VI. Make up questions to which the italicized words are the answers: ^ч

1. The milling machine is a machine for removing metal from the workpiece. 2. There are horizontal, vertical and column knee milling machines used in practice. 3. The knee is mounted on a vertical guide. 4. The saddle slides from front to back on guides. 5. A maximum distance of 15 in. is obtainable between the spindle axis and the working surface of the table.

VII. Translate the following text in written form without using a dictionary:

THE UNIVERSAL MILLING MACHINE

The cutter spindle is large in diameter, hardened and ground, and has double opposed bearings on the front end. The back end is mounted on ball bearings which are so arranged that compensation for expansion is provided. A ram type overarm with double angle bearing on the ram overarm ways provides rigid support for cutters and attachments. The column has added way length for

securely holding the ram unit. The base contains a coolant tank. The knee is massive in size to provide the greatest support for the table and saddle units. The entire feed change transmission unit is contained in the knee, and is operated through the vertical drive shaft from the drive unit located in the base and column. Dependable automatic lubrication ensures an adequate supply of oil to all moving parts.

VIII. Using the following words and word combinations describe the principle of operation and construction of the horizontal plain milling machine shown in Fig. 52:

the horizontal plain milling machine, to be provided, a column, to rise, a base, to rest, a concrete floor, the lower part of the column, to incorporate, a motor, to drive the spindle and the change gears, the upper part, to house a speed gearbox, a proper speed, an overarm, to consist, one or two heavy steel bars, to be secured, the top, the knee, to support the table and saddle, to be mounted on the face, to be moved up and down, an elevating screw, to adjust workpieces, cutters, work-holding devices, to be fastened, T-slots, cutting speed, to depend upon the nature, the work, cutting; tools

Дата добавления: 2015-07-07