XI Международная студенческая научная конференция Студенческий научный форум - 2019

One of the main tasks in any branch of engineering is the improvement and development of new equipment and cutting tools to ensure high quality products, as well as increase productivity.

The introduction of multi-operational CNC machines in the industry contributes to a new approach to the issues of machining parts technology, which will provide a significant increase in the accuracy of products.

The use of CNC machines, in which specialization by type of processing is reduced, characterizes large qualitative changes in the manufacturing industry.

Despite the great complexity and high cost of CNC equipment, its use is economically justified provided that the issues of organizational and technical re-equipment of enterprises are comprehensively addressed. The use of CNC machines is beneficial for metal cutting, pressure and in many other cases.

CNC is used not only for complex machining of parts, but is also used to perform relatively simple work.

Among quite satisfied consumers with this equipment, the number of small productions is growing, which have come to the conclusion that CNC is a new kind of equipment control systems that can be operated with high incomes. Large firms also understand that creating CNC equipment will benefit them.

Specialists who often use the cutters for a lathe when working on metal, as well as those who sell these products or supply engineering companies, are well aware of what types these tools are. For those who rarely encounter turning tools in their practice, it is rather difficult to understand their types, which are presented on the modern market in a wide variety.

Turning tool design

The design of any tool used for turning can be divided into two main elements:

1. holder with which the tool is fixed on the machine;

2. The working head, through which the processing of metal.

The working head of the tool is formed by several planes, as well as cutting edges, the sharpening angle of which depends on the characteristics of the material used to manufacture the workpiece and the type of processing. The tool holder can be made in two versions of its cross-section: square and rectangle.

By design, the cutters for turning are divided into the following types:

• straight - tools, in which the holder with their working head are located on the same axis, or on two, but parallel to each other;

• curved cutters - if you look at such a tool from the side, you can clearly see that its holder is bent;

• bent - the bend of the working head of such tools with respect to the axis of the holder is noticeable if you look at them from above;

• drawn - for such incisors, the width of the working head is less than the width of the holder. The axis of the working head of such a tool can coincide with the axis of the holder or be offset relative to it.

Classification cutters for turning

The classification of turning tools is governed by the requirements of the corresponding GOST.

According to the provisions of this document, the cutters belong to one of the following categories:

• one-piece tool made entirely of alloy steel. There are also cutters that are made entirely from tool steel, but they are used extremely rarely;

• incisors, on the working part of which a plate made of hard alloy is soldered. Tools of this type are most common;

• incisors with removable carbide plates that are attached to their working head with special screws or clamps. Incisors of this type are used much less frequently than tools of other categories.

The incisors also differ in the direction in which the feed motion takes place. So, there are:

1. turning tools of the left type - in the process of processing they are fed from left to right. If we place the left hand on top of such a cutter, then its cutting edge will be located on the side of the bent thumb;

2. right cutters - the type of tool that has received the most widespread, which is fed from right to left. To identify such a cutter, you must put your right hand on it - its cutting edge will be located, respectively, on the side of the bent thumb.

Depending on what works are performed on turning equipment, the cutters are divided into the following types:

• to perform finishing works on metal;

• for draft works, which are also called stripping;

• for semi-finishing works;

• to perform thin technological operations.

An important clarification: whatever type of cutters are, certain grades of hard alloys are used as the material of their cutting plates: VK8, T5K10, T15K6, much less frequently T30K4, etc.

Straight cutters

A tool with a straight working part is used to solve the same tasks as bent type cutters, but it is less convenient for chamfering. Basically, with such a tool for a lathe on metal (by the way, not widely used), the external surfaces of cylindrical blanks are processed.

The holders of such incisors for the lathe are made in two basic sizes:

• rectangular shape - 25x16 mm;

• square shape - 25x25 mm (products with such holders are used to perform special work).

Straight bent cutters

These types of cutters, the working part of which can be bent to the right or left side, are used for machining on the lathe the end part of the workpiece. They also chamfer.

Tool holders of this type can be made in various sizes (in mm):

• 16x10 (for educational machines);

• 20x12 (this size is considered non-standard);

• 25x16 (the most common size);

• 32x20;

• 40x25 (products with a holder of this size are mainly made to order, they are almost impossible to find in the free market).

All requirements for metal cutters for this purpose are specified in GOST 18877-73.

Straight bent bite stop

Such tools for a lathe for metal can be made with a straight or bent working part, but this design feature is not accentuated, but simply called their feedthrough.

The through stop cutter, with which the surface treatment of cylindrical billets of metal is performed on a lathe, is the most popular type of cutting tool. The design features of such a cutter, which performs processing of the workpiece along the axis of its rotation, allow even a single pass to remove a significant amount of excess metal from its surface.

Holders of products of this type can also be made in various sizes (in mm):

• 16x10;

• 20x12;

• 25x16;

• 32x20;

• 40x25.

This tool for a lathe for metal can also be made with the right or left limb of the working part.

Cutting bent cutters

Externally, such a cutting cutter is very similar to the passage, but it has a different form of the cutting plate - triangular. With the help of such tools for the lathe metalworking process in the direction perpendicular to the axis of rotation. In addition to bent, there are resistant types of such lathe tools, but the area of ​​their application is very limited.

Cutters of this type can be made with the following holder sizes (in mm):

• 16x10;

• 25x16;

• 32x20.

Cutting tools

The cutting cutter is considered the most common type of tool for a lathe for metal. In full accordance with its name, such a cutter is used for cutting pieces at a right angle. It also cuts grooves of various depths on the surface of the metal part. Determining that before you is a cutting cutter for a lathe is quite simple. Its characteristic feature is a thin leg, on which a plate made of hard alloy is soldered.

Depending on the design, right- and left-sided types of cutting tools for a lathe for metal are distinguished. To distinguish them from each other is very simple. To do this, turn the cutter with the cutting plate down and see which side its leg is located. If on the right, then it is right-sided, and if on the left, then, respectively, left-sided.

Such tools for a lathe for metal also differ by the size of the holder (in mm):

• 16x10 (for small educational machines);

• 20x12;

• 20x16 (the most common size);

• 40x25 (such massive lathe tools are difficult to find in the free market, mostly they are made to order).

Thread cutting tools for external thread

The purpose of such cutters for a lathe for metal - cutting threads on the outer surface of the workpiece. These serial tools cut a metric thread, but you can change their sharpening and cut a thread of another type with their help.

The cutting plate, mounted on such lathe tools, has a spear-like shape, it is made from the alloys mentioned above.

These cutters are made in the following sizes (in mm):

• 16x10;

• 25x16;

• 32x20 (used very rarely).

Internal threading cutters

Such cutters for a lathe can be threaded only in a hole of large diameter, which is explained by their design features. Outwardly, they resemble boring cutters for machining blind holes, but do not confuse them, since they are fundamentally different from each other.

Such metal cutters are produced in the following sizes (in mm):

• 16x16x150;

• 20x20x200;

• 25x25x300.

The tool holder for a lathe for metal has a square cross section, the dimensions of the sides of which can be determined by the first two figures in the designation. The third digit is the length of the holder. This parameter determines the depth to which the threads can be cut in the inner hole of the metal blank.

Such cutters can only be used on those lathes that are equipped with a device called a guitar.

Boring cutters for machining blind holes

Boring cutters, the cutting plate of which has a triangular shape (as in the cutting), carry out the processing of blind holes. The working part of this type of tool is made with a bend.

The holders of such incisors may have the following dimensions (in mm):

• 16x16x170;

• 20x20x200;

• 25x25x300.

The maximum diameter of a hole that can be machined with such a turning tool depends on the size of its holder.

Through-hole boring tools

Such cutters, the working part of which is made with a bend, are machined through holes, previously obtained by drilling. The depth of the hole that can be machined with a tool of this type depends on the length of its holder. The layer of metal, which is removed at the same time, is approximately equal to the amount of the limb of its working part.

Boring cutters of the following sizes are on the modern market, the requirements for which are stipulated in GOST 18882-73 (in mm):

• 16x16x170;

• 20x20x200;

• 25x25x300.

Turning tools for lathes

Considering the main types of turning tools, one cannot but mention tools with a composite construction, which are universal, as they can be equipped with cutting inserts for various purposes. For example, by fixing cutting plates of various types on one holder, it is possible to obtain cutters for machining workpieces from metal with different angles.

As a rule, such cutters are used on CNC machines or on special machines and are used for contour turning, boring blind holes and through holes and other specialized works.

Of great importance, especially for automated production, is the reliability of the tool, its adaptability to automation, low consumption of tool material and low cost.

One of the main tasks of designing technological processes for machining parts is the selection of cutting tools. Today, tool selection is most often done through paper and electronic catalogs. This is a major problem, which is a big chore. An important point in the selection of cutting tools is to prioritize the selection. For the processing of a single surface, several suitable tools can be assigned.

The first choice will have a tool that shows the best performance, both in cutting conditions and its durability.

But there are a number of other parameters or preferences of users of the tools, which can be taken into account by the choice priority.

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