Текст b: «Токарный станок»

Токарный станок по – прежнему является наиболее важным станком. Он производит детали круглого сечения поворотом ее вокруг своей оси и режущих поверхностей острым стационарным резцом. Резец можно двигать в сторону, чтобы сделать цилиндрическую деталь и двигать по направлению к детали для контроля глубины резания. В настоящее время все токарные станки с механическим приводом от электродвигателей. Это позволяет осуществлять непрерывное вращение заготовки при различных скоростях. Современный токарный станок приводится в движение посредством шпиндельной бабки, поддерживающей полый шпиндель на точных подшипниках, и подводящей либо патрон или планшайбу, на которой зажимается деталь. Движение резца вдоль станины и под прямым углом к ​​ней, позволяет точно регулировать, позволяя тем самым деталям быть обработанными, согласно допуску. Современные станки часто находятся под числовым программным управлением.

8. Ответьте на вопросы по тексту на английском языке.

1. What are machine-tools used for?

2. How are most machine-tools driven nowadays?

3. What facilities have all machine-tools?

4. How are the cutting tool and the workpiece cooled during machining?

5. What other machining methods have been developed lately?

6. What systems are used now for the manufacture of a range of products without the use of manual labor?

7. What parts can be made with lathes?

8. How can the cutting tool be moved on a lathe?

9. How is the workpiece clamped in a lathe?

10. Can we change the speeds of workpiece rotation in a lathe?

11. What is numerical control of machine tools used for?

Answers:

1. Machine-tools are used to shape metals and other materials.

2. Most machine-tools are now electrically driven.

3. All machine-tools have facilities for holding both the workpiece and the tool, and for accurately controlling the movement of the cutting tool relative to the workpiece.

4. Most machining operations generate large amounts of heat, and use cooling fluids (usually a mixture of water and oils) for cooling.

5. Other machining methods They include chemical machining, spark erosion to machine very hard materials to any shape by means of a continuous high-voltage spark (discharge) between an electrode and a workpiece. Other machining methods include drilling using ultrasound, and cutting by means of a laser beam.

6. Numerical control of machine-tools and flexible manufacturing systems have made it possible for complete systems of machine-tools to be used flexibly for the manufacture of a range of products.

7. Lathe produces parts of circular cross-section by turning the workpiece on its axis and cutting its surface with a sharp stationary tool.

8. The tool may be moved sideways to produce a cylindrical part and moved towards the workpiece to control the depth of cut.

9. The modern lathe is driven by means of a headstock supporting a hollow spindle on accurate bearings and carrying either a chuck or a faceplate, to which the workpiece is clamped.

10. Nowadays all lathes are power-driven by electric motors. That allows continuous rotation of the workpiece at a variety of speeds.

11. Numerical control is the automation of machine tools, that have made it possible for complete systems of machine-tools to be used flexibly for the manufacture of a range of products.