II. Give the English equivalents.
1) токарний верстат ......................................................
2) фасонування зовнішніх та внутрішніх поверхонь ...........................................................................................................................................................
3) нарізання різьби .........................................................................................................................
4) свердління ...................................................................................................................................
5) розточка ....................................................................................................................................
6) розшивка .....................................................................................................................................
7) вироби,ідентичні за формою .....................................................................................................
8) шаблон ........................................................................................................................................
9) шляхом обробки заготів різцем ................................................................................................
III. Speak about machine tools according to the plan.
1. What machine tool is it?
2. What is it used for?
3. What is the principle of its work?
4. Could you provide some more information about it?
5. In what does it differ from other similar machine tools?
6. Where this machine tool can be used?
7. What are the drawbacks of it?
Text 10 the lathe
T
he
modern lathe is a development of one of the earliest machine
tools. It has
played an important part in the growth of modern industry and
mass-production. Today lathes can be completely automated, i.e.
produced with computer
numerical control
(CNC),
and require minimum attention from their operators.
The engine lathe is the oldest and most common turning machine. It is used for shaping the external surface of a cylindrical part by rotating the workpiece against a cutting tool. The turret lathe carries a number of cutting tools that can be used in sequence to shape, drill, bore, ream, and cut threads on both exterior and interior cylindrical surfaces. A fully automated turning machine can feed in the work-piece and perform all cutting operations. A duplicating lathe can replicate quantities of an identical shape by using a tracing mechanism and a template.
Drilling, boring, making threads, knurling and screw-cutting are other operations that can be carried out on this versatile machine, producing work of very high precision.
The basic principle is simple. The work is fixed by some means to a spindle driven by an electric motor. As the metal revolves at speed, cutting tools are brought into contact with it and the waste is cut away. If the tool travels parallel to the spindle axis cylindrical forms are made. If the tool cuts at right angles to the axis, flat surfaces are produced. At any tool position between 0°-90° to the axis, tapers or conical forms result.