Slotting (grooving) cutters for turning grooves and cutting, their installation

Due to the peculiarities of their design, groove cutters (also called slotting cutters) are considered multifunctional tools that can be used to form grooves on workpieces of cylindrical and conical configurations. Such technological operations (especially those associated with radial grooving) are characterized by significant loads, which are successfully carried by a cutter of this type, characterized by high structural rigidity. Moreover, groove cutters are successfully used for axial grooving and facing, making them versatile turning tools.

Grooving cutters for internal and external grooves with mechanical fastening of replaceable cutting inserts

It is advisable to use groove turning tools to obtain parts with complex configurations. The versatility of cutters of this type in such cases allows us to minimize the number of tools used and reduce the time for equipment changeover. It is also noteworthy that the use of a groove cutter when performing many technological operations makes it possible to form surfaces with higher quality characteristics than when using a conventional turning tool.

Particularly successful is the use of a groove cutter when creating wide grooves on the surface of workpieces. When performing this technological operation, such a tool demonstrates exceptional durability; wear of its cutting plate occurs evenly even when performing a large number of passes. What is also important is that when using a groove cutter, the chip separation process is well controlled.

Requirements for groove-type cutters, which are produced in a wide variety of standard sizes, are specified by the provisions of GOST 18874-73.

GOST 18885-73 and 18874-73 regarding groove cutters

The contents of GOST 18874-73 “Slotting and parting cutters made of high-speed steel” and GOST 18885-73 “Threaded turning cutters with hard alloy plates” can be found below:

GOST 18874-7
GOST 18885-73

Types of groove cutters

Turning tools for forming grooves include cutters for internal and external machining. Both the first and second can be made entirely of carbide materials or have a replaceable cutting part. Carbide cutters are a fairly expensive tool, so their use must be economically feasible. When performing external work, products with replaceable inserts are usually used; using carbide groove cutters in such cases does not make sense.

The situation is completely different with the processing of internal grooves. Here it is necessary to take into account the diameter of the hole into which the cutter is to be inserted, as well as the rigidity of the tool. The requirements for a cutter to have a minimum size of its holder and sufficient rigidity to perform metal processing are met only by carbide groove tools.

Naturally, when the processing conditions and geometric parameters of the workpiece allow it, it is more advisable to use an inexpensive tool with replaceable inserts to form external and internal grooves.

Grooving turning cutters - GOSTs, varieties, manufacturers

Such technological operations (especially those associated with radial grooving) are characterized by significant loads, which are successfully carried by a cutter of this type, characterized by high structural rigidity.

Moreover, groove cutters are successfully used for axial grooving and facing, making them versatile turning tools. Grooving cutters for internal and external grooves with mechanical fastening of replaceable cutting inserts

It is also noteworthy that the use of a groove cutter when performing many technological operations makes it possible to form surfaces with higher quality characteristics than when using a conventional turning tool.

Geometry and dimensions of groove type cutters

Since groove-type cutters experience significant load during processing, which determines increased requirements for their rigidity, they are manufactured with soldered carbide plates, the characteristics of which are specified in GOST 2209-82. The requirements for the cutter itself, as stated above, are given in GOST 18874-73.

The main feature of the geometry of groove-type cutters is that the shape of their cutting part must exactly match the shape of the groove that is planned to be obtained with their help. The grooves created on the surface of the workpiece are usually small in width. Accordingly, the cutting part of the tool with which they are formed is also quite narrow, which makes it very vulnerable to mechanical damage. In addition, the working head on each side has a narrowing towards the holder (by 1–2 degrees). Such a narrowing of the sides of the cutting part is necessary in order to reduce their friction against the walls of the groove being formed.

Geometric parameters of the groove cutter

To increase the strength of the cutting head of a groove turning tool, its height is made significantly larger than its width. This also requires a small rake angle and a sharpening of the cutting edge with a small radius (curvilinear). The optimal cutting angles for groove-type cutters are 15–250 (front), 8–120 (rear).

The width of the working part of the groove tool, which, according to the requirements of GOST 18874-73, can vary over a wide range, is selected depending on the width of the groove that needs to be formed on the outer or inner surface of the workpiece.

Selection rules

The first thing you should focus on when choosing a groove turning tool is a drawing of the finished product, which indicates both the dimensions and shape of the grooves, as well as the tolerances for the accuracy of their geometric parameters. Naturally, the choice of cutter and its geometric parameters is influenced by the material from which the workpiece is made.

External groove cutter

When forming grooves on small parts, it is especially important to maintain a low cutting force, which minimizes the distortion that occurs during processing. Compliance with this requirement is ensured by the sharp sharpening of the groove tool, which, however, can lead to its breakage if the carbide plate material and cutting conditions are selected incorrectly - the rotation speed of the workpiece and the feed rate.

When choosing a groove cutter, you should also take into account the shape of its cutting edge, which can be straight and sharpened with a small radius. Naturally, you should not choose a product with a curved sharpening of the cutting edge if the bottom of the groove, according to the provided drawing, should be straight.

Internal groove cutter

Main dimensions and materials

A turning groove cutter is generally no longer than 270 mm, the width of the working head varies from 2 to 10 mm, the thickness and height in the case of a rectangular and square section of the rod reaches 50 mm. When working on machines at low speeds, carbon tool steel is used to make cutters, alloyed to speed up operations. At high speeds, high-alloy steel can be used, the speed increases up to one and a half times, the tool can withstand increased temperatures.

Inserts for turning grooves in compound cutters can be made of various materials:

carbide brazed;
metal-ceramic based on compounds of cobalt with titanium and tungsten;
mineral-ceramic, used mainly for processing high-strength parts, resistant to high temperatures, but fragile and expensive;
diamond, very durable, but burn out at high temperatures;
CBN, based on boron nitride, maintains temperature well and can process high-strength materials.

Each of the above materials is characterized by application features; when choosing, price is not the main argument - you can buy many cheap ones that cannot replace several expensive ones, but with optimal parameters. Turning groove cutters are an expensive tool; choosing them correctly will save money and will not disrupt the production cycle.

Features of turning using a groove cutter

The cutting modes when using groove-type cutters have some differences from the modes of processing the workpiece with other types of turning tools. Thus, the depth of cut is taken to be a value equal to the width of the groove being formed, and the tool feed per revolution of the part is measured in the direction perpendicular to its axis. The feed rate, depending on the material from which the cutting part of the groove tool is made, is selected in the range of 0.07–0.2 mm/rev, and the cutting speed is 15–180 m/min.

Several types of grooves can be obtained on the surface of the workpiece.

Narrow grooves, the width of which corresponds to the width of the cutting part of the tool, are made in one pass of the cutter, which is fed manually. Before this, the exact location of the groove is determined on the surface of the part, and then the cutter is placed opposite this place and fed.
The grooves on the ledges and ends of the part are made according to the same principle; their diameter is set using the transverse feed dial, and their depth is set using the longitudinal movement dial of the caliper.
Wide grooves are made in several passes according to the following scheme. First, determine the location of the right edge of the groove and place the cutter opposite this location. Using a transverse feed, the cutter is cut into the part to a depth that is 0.5 mm less than the depth of the groove being cut (this allowance is left for finishing). Then, using a longitudinal feed, the groove tool begins to move to the left edge of the groove being cut, the boundary of which has been previously marked. After the rough groove is formed, its bottom is processed cleanly - to the required depth, carrying out the longitudinal feed of the cutter from left to right. In the event that it is necessary to form a groove with a very precise location of its left and right edges, allowances can also be left on them during roughing, which are then removed using the transverse feed of a groove or scoring cutter.

Types of work performed by grooving cutters

Recommendations for selecting groove cutters

When choosing a groove cutter, you should be guided by the following considerations:

First of all, they analyze the drawing according to which the part will be manufactured. The drawing shows all the parameters of the grooves: width, depth, shape, as well as standards for manufacturing accuracy and possible tolerances.
The metal from which the part is made. For carbide metals, appropriate cutters with a carbide blade are used; for soft metals, ordinary grooved ones are used.
When choosing a tool for cutting grooves inside a hole, the diameter of the holder and the size of the protruding edge of the knife are important. Here, too, it is more advisable to use carbide equipment.
Equipment for carrying out operations. The choice of groove cutter is determined in this case depending on the possible operating modes of the machine, the configuration and type of tool holder.
Features of the technological process. The technical process can affect the processing speed of the product. The higher the speed, the stronger and more durable the grooving equipment must be used to achieve processing goals.
Is there any provision for lubrication of the treatment area during the operation? Lubrication has a positive effect on the work, removing part of the load from the groove tool and thereby making it possible to use simpler equipment.

Labeling and manufacturers

The description of groove turning tools will be incomplete without mentioning the markings, which determine the composition of the material of their cutting part. For example, the T5K10 cutter is made of a hard alloy of the titanium-tungsten group, which contains 5% titanium carbide and 10% cobalt. The markings of products made from other materials are deciphered in a similar way.

The most famous manufacturers of grooving turning tools are:

Dnepropetrovsk industrial tools plant (Ukraine);
(Ukraine);
Zenitech company (Switzerland);
Proma company (Czech Republic);
Itertool company (China).