How to determine which incisor is right or left. Structural elements and geometrical parameters of through turning tools. Turning tool

Basic concepts of metal cutting and cutting tools

The founders of the theory of cutting metals were the outstanding Russian scientists I. A. Time (1838-1920), K. A. Zvorykin (1861-1928), Ya. G. Usachev (1873-1941) and others. The works of these scientists, which received world recognition have not yet lost their value. However, in the conditions of backward tsarist Russia, all these works did not find practical application because the industry was underdeveloped.

The science of metal cutting gained wide scope only after the Great October Socialist Revolution, especially during the Soviet five-year plans, when science was placed at the service of socialist industry.

Soviet scientists V. D. Kuznetsov, V. A. Krivoukhov, I. M. Bezprozvanny, A. M. Rozenberg, M. N. Larin, P. P. Trudov, M. I. Klushin and others created a national cutting school metals, distinctive feature which is the close collaboration of science with production, scientists with innovators of production.

An important role in the development of the science of cutting metals was played by the movement of innovators in production. In an effort to increase labor productivity, production leaders began to look for new ways to improve cutting conditions: they created a new cutting tool geometry, changed cutting conditions, mastered new cutting materials. Each workplace Turner-innovator has become like a small laboratory for the study of the cutting process.

A broad exchange of experience, possible only under the conditions of a socialist economy, and close cooperation between leading workers in production and science ensured the rapid development of the science of cutting metals.

Cutter work

Klin and his work. The working part of any cutting tool is wedge(Fig. 44). Under the action of the applied force, the tip of the wedge cuts into the metal. The sharper the wedge, that is, the smaller the angle formed by its sides, the less force is required to cut it into the metal. The angle formed by the sides of the wedge is called taper angle and is denoted by the Greek letter β ( beta). Therefore, the smaller the taper angle β, the easier the wedge penetrates into the metal, and, conversely, the larger the taper angle β, the greater the force must be applied to cut the metal. When assigning the taper angle, it is necessary to take into account the mechanical properties of the metal being processed. If cut solid metal with a cutter having a small sharpening angle β, then the thin blade will not withstand and will crumble or break. Therefore, depending on the hardness of the metal being processed, an appropriate wedge sharpening angle is assigned.

The layer of metal being processed, located directly in front of the cutter, is continuously compressed by its front surface. When the force of the cutter exceeds the forces of adhesion of metal particles, the compressed element is sheared and shifted by the front surface of the wedge upwards. The cutter, moving forward under the action of the applied force, will continue to compress, chip and shift the individual elements from which the chips are formed.

Basic movements in turning. When machining on lathes, the workpiece rotates, and the cutter receives movement in the longitudinal or transverse direction. The rotation of the workpiece is called main movement, and the movement of the cutter relative to the part - feed motion(Fig. 45).

Main parts and elements turning tool

The cutter consists of two main parts: the head and the body (rod) (Fig. 46). Head is the working (cutting) part of the cutter; body serves to secure the cutter in the tool holder.

The head consists of the following elements: front surface, along which the chips come off, and rear surfaces facing the workpiece. One of the rear surfaces facing the cutting surface is called main; the other, facing the treated surface, - auxiliary.

Cutting edges are obtained from the intersection of the front and back surfaces. Distinguish home and auxiliary cutting edge. Most of the cutting work is done by the main cutting edge.

People who process metal parts using cutters for a metal lathe, tool sellers are well aware of what types they are divided into. Those who occasionally use turning tools for metal often experience difficulty in choosing the right option. By reading the information below, you will be able to special work choose the right tool for your needs.

Design features

Each turning tool for metal consists of the following main parts:

• holder. Designed to be fixed on a turning device;
• working head. Used for processing parts.

The working head of the metal-cutting device contains various planes, edges. Their sharpening angle depends on the indicators of the steel from which the part is made, the type of processing. The tool holder for a metal lathe usually has a square or rectangular section.

Structurally, it is possible to distinguish the following types of incisors:

1. Direct. The holder and the head are either on the same axis or on two axes that lie in parallel.
2. Curved. The holder has a curved shape.
3. Bent. If you look at the top of such a tool, you will notice that its head is bent.
4. Drawn. The head has a width smaller than the holder. The axes either coincide or are shifted relative to each other.

Varieties

The classification of turning tools is regulated by the rules of a certain standard. According to its requirements, these devices are divided into the following groups:

1. Whole. Made entirely of alloy steel. There are fixtures that are made from tool steel, but they are rarely used.
2. Devices, on the working element of which carbide inserts for turning tools are soldered. Most common at present.
3. Turning cutters with replaceable inserts made of hard alloys. The plates are attached to the head with special screws, clamping devices. They are not used as often as other types of models.

Besides, devices differ in the direction of delivery. They can be:

• Leftists. The feed goes to the right. If you put your left hand on top of the tool, the cutting edge will be near the thumb, which is bent.
• Right. They are used most often, the feed goes to the left.

The types and purpose of turning tools form the following classification:

• carrying out finishing processing of the product;
• roughing (peeling);
• semi-finishing;
• execution of operations that require high precision.

From whatever category the metal-cutting tool is, it plates are made of hard alloy materials: VK8, T5K10, T15K6. Occasionally, T30K4 is used. Now there are many types of turning tools.

Straight through

Turning cutters have the same purpose as the bent version, but it is better to cut chamfers with a different device. Usually they carry out the processing of the outer surfaces of steel parts.

The dimensions, or rather, their holders, can be as follows:

• 25 × 16 mm - rectangle;
• 25×25 - square (these models are used for special operations).

Bent through

These types of turning tools, the working head of which can be bent to the left / right, are used for machining the ends of parts. In addition, by means of them it is possible to cut chamfers.

Holders have sizes:

• 16×10 - educational devices;
• 20×12 - non-standard size;
• 25x16 is the most commonly used size;
• 32×20;
• 40×25 - with a holder of this size, they are usually made to order, it is almost impossible to buy them in a store.

All requirements for turning mechanical cutters are spelled out in state standard 18877-73.

Thrust bushings

These types of turning tools can have a straight or bent head, but this design feature is not taken into account in the marking. They are simply called stubborn walkers.

This device, with which the surface of cylindrical metal parts is processed on the machine, is the most popular type of cutting equipment. The design makes it possible to remove from the workpiece in 1 pass a large number of metal surplus. Processing is carried out along the axis of rotation of the part.

The holders of thrust turning cutters are available in the following sizes:

• 16×10;
• 20×12;
• 25×16;
• 32×20;
• 40×25

Bent scoring

It looks like a through passage, but has a different shape of the cutting plate (triangle). By means of such tools, parts are machined in a direction that is perpendicular to the axis of rotation. In addition to bent, there are persistent cutters, but they are rarely used.

Holder sizes are as follows:

• 16×10;
• 25×16;
• 32×20

Cut-off

The turning cutter is very common at the present time. According to its own name, it is used to cut parts at an angle of 90 degrees. Also, through it, grooves of different depths are made. It is quite easy to understand that you have a cutting tool in front of you. It has a thin leg with a hard-alloy plate soldered onto it.

Depending on the design, there are left- and right-hand cutting devices. It's easy to tell them apart. You need to turn the tool over with the cutting plate down and look at which side the leg is on.

Holder sizes are as follows:

• 16×10 - training equipment;
• 20×12;
• 20 × 16 - the most common;
• 40×25

Thread-cutting for external thread

The purpose of these devices is to cut threads on the outside of the part. Usually do metric thread, however, if you change the sharpening, it is possible to create a different type of thread.

The cutting plate that is mounted on this tool, has the shape of a spear. Materials of turning tools - hard alloys.

Thread-cutting for internal thread

With this tool, it is possible to make a thread only in a large hole. This is due to the design features. In appearance, it looks like a boring device for processing blind holes. However, these tools should not be confused. They differ significantly.

Holder dimensions:

• 16x16x150;
• 20x20x200;
• 25x25x300

The holder has a section in the form of a square. Sizes can be set by the first two numbers in the marking. 3rd number - the size of the holder. It determines the depth to which it is possible to thread the thread in the inner hole.

These instruments can only be used on devices equipped with a guitar (special accessory).

Boring for blind holes

The plate has the shape of a triangle. Purpose - processing blind holes. The working head is bent.

Sizes:

• 16x16x170;
• 20x20x200;
• 25x25x300

The largest hole radius that can be machined with boring cutter, depends on the size of the holder.

Boring for through holes

Tools are designed for processing through holes that are created during drilling. The depth of the hole that can be created on the device depends on the size of the holder. The layer of material removed during the operation is approximately equal to the bend of the head.

Today in stores there are boring tools of these sizes:

• 16x16x170;
• 20x20x200;
• 25x25x300

prefabricated

When it comes to the main types of turning tools, it is necessary to mention prefabricated ones. They are considered universal, because they can be equipped with cutting plates for various purposes. For example, fixing cutting inserts on one holder different kind, it is possible to obtain tools for processing metal parts at a variety of angles on the device.

Typically, prefabricated cutters are used on devices with a numerical program management or special equipment. They are intended for turning contours, boring blind and through holes, and other turning operations.

When choosing a tool with which metal parts will be processed on a special device, you need to Special attention turn to the elements of the turning tool. The holder and working head are the most important parts of the cutting fixture. It depends on them how well the processing of the steel billet will be performed, what size holes can be made. If you choose the wrong working tool, you may encounter various difficulties when processing a metal part. It is recommended to study the classification, to understand what this or that product is intended for. Based on the knowledge gained, you will be able to right choice metal cutting tool.

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Cutter is the main cutting tool used on machine tools. The cutter consists of two parts: the head (cutting part) and the rod (body), which serves to fix the cutter (Fig. 5, a).

Rice. 5. Parts(a) and elements(b) incisor: 1 - front, 2 - rear surface, 3 - cutting edge

The main elements of the cutter head (Fig. 5, b) are:

anterior surface(ABCD) 1, on which the chips come off;

rear surface(ABEF) 2 facing the machined surface;

cutting edge(AB) 3 (see Fig. 5, b), formed by the intersection of the front and rear surfaces. The mutual arrangement of the front and rear surfaces is always such that a wedge-shaped CBE is formed in a section perpendicular to the cutting edge. Depending on the shape and purpose of the cutter, it can have one front and several back surfaces, while the number of cutting edges will be equal to the number of back surfaces. The cutting edges are divided into main, auxiliary and transitional.

The main cutting edge is called the cutting edge, which removes the bulk of the cut metal layer left as an allowance for processing.

Auxiliary cutting edges are edges that remove a small part of the cut layer, they face the machined surface and make a certain angle with the main cutting edge (Fig. 6).

Rice. 6. Surfaces and the elements of the cutter formed by them:

surfaces: 1 - auxiliary back, 3 - front, 6 - main back; edges: 2 - auxiliary cutting, 4 - main cutting; 5 - top

The transitional cutting edge is the edge formed by the mating of the main and auxiliary cutting edges.

Rice. 7. Transitional cutting edge(1) and transitional back surface (2) incisor

Transitional cutting edges are in the form of an arc or chamfer 1 (Fig. 7).

In rare cases, only the main cutting edge is involved in cutting. This happens when the width of the machined surface is less than the length of the main cutting edge (see Fig. 5, b).

The intersection of the main and auxiliary cutting edges forms the top 5 (see Fig. 6) of the cutter.

The main rear surface 6 (see Fig. 6) is the surface adjacent to the main cutting edge.

The secondary rear surface 1 is the surface adjacent to the secondary cutting edge. The transitional rear surface 2 (see Fig. 7) is the surface adjacent to the transitional cutting edge.

The cutters are subdivided according to the direction of feed, according to head shape, on manufacturing method and by type of work performed.

Feed direction incisors are rights and left. The right and left incisors are determined by placing a hand on the incisor. To determine the type of incisor, a hand is placed on it with the palm down so that the fingers are directed towards the top of the incisor; the left is called the incisor, the main cutting edge of which coincides in location with the direction of the thumb of the left hand (Fig. 8, a); right is called a cutter, the main cutting edge of which coincides in location with the direction of the thumb of the right hand.

Rice. eight. Types of cutters:

a - right and left in the form of heads, b - straight, c - bent, d - curved, e - with a drawn head

According to the shape of the head incisors are divided into straight and bent.

Direct(Fig. 8, b) incisors are called incisors, in which the axis of the incisor head is a continuation or parallel to the axis of the incisor body.

bent incisors (Fig. 8, c) are called incisors, in which the axis of the incisor head is tilted to the right or left of the axis of the incisor body. According to the shape of the rod, straight and curved incisors are distinguished. In curved incisors, the axis of the incisor body is curved when viewed from the side (Fig. 8d).

Incisors, in which the working part (head) is narrower than the rod, are called incisors with a drawn head (Fig. 8, e). The retracted head can be symmetrical with respect to the axis of the incisor, retracted to the right, when, when applied to the incisor of the palm of the right hand, the head is shifted towards the thumb of the right hand, or retracted to the left, when when the palm of the left hand is applied, the head is shifted towards the thumb of the left hand.

By manufacturing method distinguish incisors whole and composite.

Solid cutters made from one piece of tool material, composite - from two separate parts - a plate and a rod or a head and a rod. Solid cutters made of carbon or alloy tool steel. At composite incisors the heads or blades are made of high-speed steel (the blades are also made of hard alloys), and the rods are made of structural steel. HSS blades or heads are welded, while carbide blades are brazed or mechanically fastened.

By type of work performed cutters are divided into rough and finish through-threads, shaped, cutting, grooving, etc.

When working on lathes, various cutting tools are used: cutters, drills, countersinks, reamers, taps, dies, shaped tools, etc. Turning cutters are the most common tool, they are used for processing planes, cylindrical and shaped surfaces, threading, etc. e. The elements of the cutter are shown in the figure. The cutter consists of a head (working part) and a rod that serves to fix the cutter in the tool holder. The front surface of the cutter is the surface along which the chips come off. Back (main and auxiliary) are the surfaces facing the workpiece. The main cutting edge performs the main cutting work. It is formed by the intersection of the front and main back surfaces of the cutter. The secondary cutting edge is formed by the intersection of the front and secondary rear surfaces. The top of the cutter is the intersection of the main and auxiliary cutting edges.

To determine the angles of the cutter, the concepts are established: the cutting plane and the main plane. The cutting plane is called the plane tangent to the cutting surface and passing through the main cutting edge of the cutter (see figure). The main plane is called the plane parallel to the direction of the longitudinal and transverse feeds; it coincides with the lower supporting surface of the cutter. The angles of the cutter are divided into main and auxiliary (see figure). The main angles of the cutter are measured in the main cutting plane, i.e., the plane perpendicular to the projection of the main cutting edge onto the main plane.

The main clearance angle α is the angle between the main rear surface of the cutter and the cutting plane. Pointing angle β is the angle between the front and main rear surfaces of the cutter. The main rake angle γ is the angle between the front surface of the cutter and the plane perpendicular to the cutting plane and passing through the main cutting edge of the cutter. The sum of angles α+β+γ=90 degrees. The cutting angle δ is the angle between the front surface of the cutter and the cutting plane. The main angle in the plan φ is the angle between the projection of the main cutting edge on the main plane and the feed direction. Auxiliary angle in terms of φ1 is the angle between the projection of the secondary cutting edge on the main plane and the feed direction. The angle at the top in terms of ε is the angle between the projections of the main and auxiliary cutting edges on the main plane. The secondary clearance angle α1 is the angle between the secondary clearance surface and the plane passing through the secondary cutting edge perpendicular to the main plane. The angle of inclination of the main cutting edge λ is the angle between the main cutting edge and the plane passing through the top of the cutter parallel to the main plane. The cutters are classified: in the direction of feed - into right and left (right cutters on a lathe work when fed from right to left, that is, they move to the headstock of the machine); according to the design of the head - into straight, bent and drawn (see figure);

Incisors: a - straight, b - bent, c - drawn

according to the type of material - from high-speed steel, hard alloy, etc.; according to the manufacturing method - into solid and composite (when using expensive cutting materials, the cutters are made composite: the head is made of tool material, and the rod is made of structural carbon steel; composite cutters with hard alloy plates that are soldered or mechanically fastened are most widely used); according to the cross section of the rod - into rectangular, round and square; according to the type of processing - for through-hole, cutting, cutting, slotting, boring, shaped, thread-cutting, etc. (see figure).

Turning cutters for various types of processing:

a - external turning with a curved through cutter, b - external turning with a straight through cutter, c - turning with cutting the ledge at a right angle, d - cutting a groove, e - turning a radius fillet, e - boring a hole, g, h, i - threading external, internal and special

And so hello friends! Today we will talk about what are the main parts and elements of a turning tool. We need this topic because it is necessary to know for further study of machining on lathes.

In order to make it more clear, let's look at this figure, which shows a turning tool and its main components are indicated. Or how they can be called the elements of the cutter. Of course, you can blame me for citing a very ancient cutter as an example, but excuse me, this is a classic.

The elements of the turning tool are divided into:

1. This is the so-called kernel(or holder) of the cutter itself. It directly serves to hold the tool in the tool holder of a lathe or turret.

2. front surface. Chips come off along it in the process and fall into the frame.

3. Cutter tip. Well, I want to tell you right away that the top of the turning tool should be strictly along the axis of the workpiece being processed, not lower and not higher, otherwise there will be increased wear on the cutting insert and, as a result, its destruction.

4. Main cutting edge. Well, everything is clear here) the main edge is directly involved in the cutting process, and to put it simply, it cuts the metal from the workpiece.

5. Main back surface. Has an angle similar to the slope main cutting edge but does not participate in cutting metal.

6. Secondary cutting edge. Does not participate in the cutting process, I honestly don’t remember why it is 🙂 if anyone remembers, write in the comments, we will discuss and discuss.

7. Auxiliary rear surface. This surface is a continuation of the clearance angle of the secondary cutting edge.

In general, it is not so difficult to remember that under the main cutting edge there is the main back surface and under the auxiliary, respectively, the auxiliary surface. Uff well, and twisted)))))

YEEES! you probably noticed that in the above figure there is also a footnote called cutter head. But I didn’t forget about it, I just wanted to tell you about it, namely that all of the above points except for the rod or holder are the head of the turning tool.

Well, of course, you now say that I talked about the design of a “prehistoric” turning tool and you will be partly right, this is a turning tool with a brazed insert BUT a cutting tool with non-regrindable carbide inserts has the same surfaces - THIS IS A CLASSIC 🙂.

Video about the main parts and elements of a turning tool:

OK it's all over Now. I think that after reading my article about the main parts and structural elements of a turning tool, fixing everything with this, in my opinion, a fairly sensible video, you understand what's what. Well, if not, write in the comments that it is not clear, we will figure it out together. SEE YOU!!!

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Andrew was with you!