II. Reading.

Ex.5. Read and translate the text:

Text a Milling machines

1. Milling machines are used for milling operations. Milling is the process of removing material from work with a multi-toothed rotating cutter. There are various classes and types of milling machines in use, from small hand-operated types to fully automatic ones, the main of them being: column and knee type, bed type, planer type, and rotary type. Column and knee type, milling machines are made in three styles: horizontal plain, vertical and universal spindle milling machines.

2. The horizontal milling machine is provided with a massive column rising from a base which rests on a solid wooden or con­crete floor which is sufficiently heavy to withstand the weight of the machine. The base, hol­low inside, contains a coolant tank with cutting fluid that is delivered through piping by means of a motor-operated pump to the cutters. The centrifugal type pump is mounted on the pad located at the side of the base and is connected directly to the coolant tank. The cutting fluid flow can be regulated by means of valves connected to the outlet nozzles which can be swivel­led for distributing a low pressure volume of cutting fluid to all diameter and types of cutters. A constant supply of clear oil is pumped to the column and feed gearbox. In the lower part of the column there is a motor for driving the spindle and the change gears for the power feed. A set of change gears for dri­ving the spindle at a proper speed is housed in the upper part of the column. The change gears are shifted either manually by a spindle speed change lever or by power to form various trains for providing the necessary cutting speeds.

3. The horizontal plain milling machine has a horizontal spindle rotating in anti-friction bearings in the column. The spindle is a hardened, ground, hollow shaft spaced horizontally from the front to the back of the column. Secured to the top of the column is an overarm consisting of one or two heavy steel bars. The knee which supports the table and saddle units is moun­ted on the face of the column and can be moved up and down by me­ans of an elevating screw for adjusting workpieces with respect to cutters.

4. Vertical spindle machines are similar to plain milling ma­chines, but their spindle is positioned vertically.

5. Universal milling machines are also similar to plain mil­ling machines but the saddle is mounted on and swivels on clamp bed which slides on the knee: thus permitting the saddle to swing at an angle, and permitting table motion at other angles than 90° to the spindle axis.

6. Cutting speeds on the milling machine depend upon the na­ture of the work, the type of cutter, the condition of the machine and upon the experience and ability of the machine operator. Feed rates in milling are expressed in two ways: in, per min, or thousandth of an inch per revolution of the spindle.

III. Language.

Ex.6. Match word and word combination in column A with those in column B:

A B

1. зрушувати 1. remove

2. виступ 2.cutter

3. брусок 3.withstand

4. подання 4.deliver

5. полозка 5.valve

6. зміцнювати 6.supply

7. видаляти 7.shift

8. клапан 8.knee

9. фреза 9.secure

10. витримати 10.nose

11. постачати 11.bar

12. коліно 12.saddle

Ex.7. Fill in the blanks using the following words:

a) work; b) power feed; c) contains; d) knee; e) swivels; f) hardened

1. The saddle in universal milling machine is mounted on and _______ on a clamp bed.

2. The spindle is _______ ground, hollow shaft spaced horizontally from the front to the back of the column.

3. The ______ is mounted on the face of the column and can be moved up and down by means of elevating screw.

4. Milling is the process of removing material from _______ with multitoothed rotating cutter.

5. The base hollow inside, ________ a coolant tank with cutting fluid.

6. In the laver part of the column there is a motor for drilling the spindle and the change gears of _______ .

Ex.8. Find the right ending of the sentences and translate these sentences:

1. The base, hollow inside, contains a coolant tank with cutting fluid that is

a) sufficiently heavy to withstand the weight of the machine;

b) connected directly to the coolant tank;

c) delivered through piping by means of a pump to the cutters

2. The centrifugal type pump is mounted

a) on the face of the column;

b) on the pad located at the side of the base;

c) on a solid wooden floor

3. The cutting fluid flow can be regulated by means of

a) valves connected to the outlet nozzles;

b) a motor-operated pump;

c) gears, shafts and bearings throughout the column.

4. In the lower part of the column there is

a) the knee which supports the table;

b) the charge gears for the power feed;

c) a motor for driving the spindle

5. In the upper part of the column there is

a) a set of change gears for driving the spindle at a proper speed;

b) various trains for providing the necessary cutting speeds

6. An overarm, consisting of one or two heavy steel bars is

a) attached to the spindle nose;

b) carried on an arbor;

c) secured to the top of the column.

Ex.9. Put questions to get the following answers:

1. Milling machines are used for milling operations.

2. Column and knee-type, milling machines are made in three styles: horizontal plain, vertical and universal spindle milling machines.

3. The centrifugal type pump is mounted on the pad located at the side of the base.

4. A constant supply of clear oil is pumped to the column and feed gearbox.

5. The horizontal plain milling machine has a horizontal spindle rotating in anti-friction bearings in the column.

6. Feed rates in milling are expressed in two ways: in, per min, or thousandth of an inch per revolution of the spindle.