Turning is one of the main ways of processing a metal product, in which the extra layer is removed from it. The result is a part of the desired size, shape and degree of roughness.
Lathe processing
general information
The processing procedure is carried out on a special lathe, which with the help of cutters, drills or other cutting devices cut from the workpiece parts a layer of metal of the desired thickness. The rotation of the workpiece is called the main movement, and moving the tool, which provides continuous processing of the product to the desired parameters, called the feed movement.
The lathe is able to perform various combinations of these two types of movement, therefore on it carrying out of effective processing of cylindrical is possible, threaded, shaped, conical and other surfaces. This includes clutches, nuts, bushings, pulleys, ??it's raining, gears and rings.
Lathes allow the following types of work:
- threading;
- drilling, boring, deployment and countersinking of various holes;
- grooving;
- cutting the part into several parts.
These basic types of turning of metal parts involve the use of various measuring instruments (micrometers, calipers, inside gauges, extreme calibers), which help to determine the size and shape, as well as to control the relative position of different surfaces of the product.
The essence of metal turning is as follows. When inserting a cutting tool into a part, the product is clamped by the edge of the cutter. At the same time the tool overcomes forces of coupling in a detail and removes an superfluous layer of metal in the form of shaving.
There are the following types of shavings:
- elemental - obtained by turning hard and low-viscosity products at low speed;
- fracture - characteristic of cutting low-plastic parts;
- drain - is obtained by turning at fairly high speeds of copper products, lead, tin or plastic, as well as mild steel blanks;
- stepped - typical for turning at medium speeds of aluminum alloys, products from sheets of aluminum and steel of average hardness.
Drain shavings when processing viscous materials
Classification of incisors
The productivity of the lathe directly depends on the amount of longitudinal feed of the product for processing, cutting speed and cutting depth. It is thanks to these parameters that you can achieve:
- good speed of rotation of the lathe shaft and the processing of the metal product;
- the stability of the cutting tool and the desired level of its impact on the part;
- the required amount of metal shavings, formed in the process of turning the workpiece;
- maintaining the surface of the lathe in working condition.
The cutting speed depends on the type of material, subject to turning, as well as the type and quality of cutters used. The index of turning of a detail and speed of cutting of these or those lathes establish frequency of rotation of a shaft. Density and other basic parameters of blanks can be learned from specialized tables and specifications of metal parts.
Cutters for lathes are finished and rough - their appearance depends on the nature of the workpiece. The geometric dimensions of their cutting part allow you to work with a small, and with a large layer area, which must be removed from the workpiece. In the direction of movement of the lathe cutters are divided into left and right. The first move from left to right (from front to back headstock), the second, in accordance, right to left.
The location and shape of the blade cutters are bent, straight and extended. In the latter, the width of the mounting part is greater than the width of the cutters. Turning cutters are also divided into:
- threaded;
- detachable;
- shaped;
- boring;
- checkpoints;
- grooves;
- undercut.
Types of turning cutters
The geometry of a lathe has a strong influence on the quality and accuracy of cutting. Turning of metal is most effective in that case, if the shape of the cutter is chosen correctly. To do this, the turner must be familiar with the concept of "angles in the plan". These are the angles between the feed direction of the part and the edges of the cutter:
- ? (Main);
- ?1 (auxiliary);
- ? (At the top).
The angle at the top depends on the sharpening of the cutter, and the main and auxiliary - also from its installation. If the main angle is large, then only a small part of the edge will work, which means, that the stability of the cutter will decrease. At small value of an angle the cutter has greater stability, and its heating is removed much more efficiently. When turning thin and non-rigid parts usually choose the angle in 60-90 °, for details, which are larger in cross section, — 35-40 °.
Auxiliary corner, usually, is equal to 10-30 °. Its increase is meaningless, since the top of the cutter will weaken. For simultaneous turning of a cylindrical surface and the end plane usually use through thrust cutters. Curved and straight cutters are best suited for finishing the outer surfaces of the part, detachable - for drilling grooves and separating parts, boring (through or persistent) - for boring of openings, drilled before.
geometry of cutters
Turning of shaped surfaces, forming a line which does not exceed in length 4 cm, carried out with the help of shaped cutters. They are classified by design and movement of the feed. The following types of shaped cutters are distinguished by design:
- rod;
- round;
- prismatic.
According to the feed movement shaped cutters are divided into:
- tangential;
- radial.
You can get more detailed and visual information about the types of lathes and their purpose by watching a video on this topic.
types of machines
Turning is carried out on different types of machines, but the most commonly used today is a lathe. It is universal in its capabilities, therefore its application is admissible not only on large manufactures, but also at enterprises, specializing in small-scale production.
Screw-cutting lathe 16K20
This machine consists of the following mandatory elements:
- front headstock with spindle and gearbox and rear headstock with quill, body and longitudinal sledges;
- caliper;
- beds with pedestals (engines are located in curbstones);
- feed boxes.
Turning and milling in order to obtain the most accurate geometric parameters is carried out using programmable machines, practically do not differ in the design from universal devices (you can find videos on the Internet, which clearly shows the processing on such lathes of metal workpieces from different angles).
CNC lathe
In addition to these types of lathes, there are also:
- turning and revolving;
- rotary lathes;
- multi-cutter semi-automatic (ideal for large-scale production);
- screw-cutting lathes;
- modern machining turning and milling complexes.