Installation of cutters. Installation of cutters in machines. Technical requirements for milling tools

Alignment of milling cutters with interchangeable inserts and their fixing in the body are carried out in the tool shop before the cutter is installed in the machine. The location of the blades of the insert knives on the same cutting circle is a condition for the participation of all of them in the work and quality processing. Therefore, the alignment of knives is a very important operation that requires great care. For its implementation, we can recommend devices developed by SverdNIIPDrev.
Attachment knife alignment tool cylindrical cutters(Fig. 56, a) has the main working body, carrying out a forced fit of the cutter blade to the control element in the form of an electromagnet 6 W-shape. To do this, the cutter must be clamped between the cones 3 and 8 using the screw 2 and the nut-rack 1. The cone 8 is fixed motionless on the plate stand 7. The carriage-support 4 protects the screw from deformation when the cutter is installed and moves along the guides 5. The required position of the knife relative to the magnet is fixed by a dividing disk, made in one piece with the cone 8 and the stopper 10. The bolts for fastening the knives are tightened when the magnet is turned on. The knife exhibition value is set and controlled using indicator 9.

On fig. 56, b shows a device for installing cutters in disk cutters. The cutter is fixed on the cone head 1 with ball clamps. The control element that sets the position of the cutter is also an electromagnet 2. For the location of the side cutting edges a shelf 5 is provided in the horizontal plane, rigidly connected to the electromagnet on the movable rack. The position of the electromagnet relative to the axis of the tool is fixed using a ball lock 4, and its vertical movement is fixed using a lead screw 5 and a nut 6. A measuring tool 8 is attached to the stand 7 to check the accuracy of the cutter installation. The vertical position of the micrometer is regulated by screw 9 and nut 10, and horizontally by screw 11. The inaccuracy of installing knives using these devices does not exceed 0.05-0.06 mm, which does not go beyond the allowable 0.08-0.09 mm .
Shell mill balancing performed on a special device PI-25 to prevent their imbalance. The cutter is mounted on a ground mandrel and mounted on horizontal cylindrical rollers, then with a slight push of the hand, the mandrel with the cutter is forced to roll along the rollers. In the presence of imbalance, the cutter will always stop in one position - the heavy side down. Balancing is done by grinding metal from the heavy non-working side until the cutter stops in any position.
Installation and fixing of cutters. The cutter is fixed on the spindle different ways: depending on the design of the machine spindle and cutter. End mills are mounted on the motor spindle using conventional three-jaw self-centering or collet chucks. The easiest way to fix the shell cutter on the spindle 1 of milling machines is by fixing it with tightening nuts 4, 2 and intermediate rings 3 (Fig. 57, a). The position of the cutter relative to the table is adjusted by extending the spindle or by selecting intermediate rings. In the absence of vertical movement of the spindle, the cutters are fixed on it in special heads (Fig. 57, b), which have a device for adjusting the position of the cutter relative to the table machine. When the bolt 1 rotates, the conical bush 2, moving up along the inner conical surface of the head 3, tightly compresses the spindle 5, fixing the cutter in the desired position. This position is preliminarily set by the adjusting screw 4 resting against the machine spindle. Fastening of cutters on horizontal shafts can be carried out using one or two collets, the presence of which is provided for by the normals for the design of the cutter. In some cases, the milling tool is directly put on the machine spindle and secured with a clamping nut. The coupling of the cutter with the spindle in this case is carried out according to a sliding fit of the 2nd accuracy class.

The following are the technical requirements for milling tool:
1. The body of the cutters must be made of structural steels 40X and X45, and the cutting elements - from steels X6VF, P4, P9 or reinforced with carbide plates.
2. The roughness of the edges should not be lower than the 8th class according to GOST 2789-59.
3. Tolerances angular parameters must not exceed for front angle 2°, for rear corner
4. Radial runout should not exceed 0.5-0.08 mm, end runout - 0.03 mm.

Selecting a machining method for milling. Depending on the material of the workpiece, it is necessary to set the processing method - up or down milling (see Fig. 2.20). Up milling is used for viscous materials, and climb milling is used for brittle ones in order to prevent chipping of the workpiece edge. With climb milling, which is permissible on a machine with an appropriate design of the feed mechanism, before starting work, it is necessary to eliminate the gap (“backlash”) in the screw-nut pair of the table movement mechanism.

Before starting setup milling machine, carry out its preparation for work, which consists of checking the serviceability and readiness of the machine to perform various milling operations. At idle, they check the execution by the machine of commands to start and stop the electric motor, turn the spindle rotation on and off, turn the mechanical table feeds on and off.

After making sure that the machine is working, proceed to its adjustment. We will consider the methods of setting up machines of the milling group using the example of universal console milling machines with manual control.

Setting cutting data. When setting the specified setup card or the spindle speed master 6 (see Fig. 5.2), it is necessary to pull the switch handle 1 in the gearbox 5 towards you, and then turn it to the right around the axis to the required position until it matches set frequency on the limb there are 3 handles with an arrow pointer on the body of the box 5. After that, the handle is pushed back (away from you).

Similarly to the spindle speed, the preset feed is adjusted in the box 13 when the handle 15 with the limb 16 is moved. The feed movement in universal console milling machines is performed by table 9, moving in three directions - longitudinal, transverse and vertical. The calculation of the elements of the cutting mode is carried out according to kinematic scheme machine (see fig. 5.3).

Before starting processing on the machine, it is necessary to securely clamp the slide along which the table moves, as well as the consoles on the machine stand. Depending on the overall dimensions workpiece (jigs) installed on the table, determine required values its moves (taking into account the descent (runaway) of the tool) and place the cams that limit the course and turn off the mechanical feed of the table.

Setting up the cutting tool. Cylindrical and disk cutters are fixed on a mandrel, the tapered shank of which is tightened in the spindle cone with a ramrod. Milling mandrels can be long (see Fig. 5.7) or short (end). The free end of the long mandrel is supported by the trunk bracket in universal cantilever milling machines with a horizontal spindle.

Rice. 9.5. Tool mounting on universal console milling machines with a horizontal spindle:
1 - ramrod; 2, 4, 5 - nuts; 3 - trunk; 6 - mandrel; 7- axle box; 8 - suspension; 9 - cutter; 10 - bushing; 11 - spindle; 12 - rack

Installation of the cutter 9 (Fig. 9.5) on a long mandrel 6 of the horizontal spindle 11 is carried out using intermediate bushings 10, placing the cutter as close as possible to the end of the box 7 of the suspension 8. To avoid vibration, special attention should be paid to securely fixing the cutter 9 on the mandrel 6 directly or through ramrod 1 with nut 5, as well as hangers 8 on trunk 3 with nut 4 and trunk 3 on rack 12 with nut 2.

(Schemes and designs for installing cutters of other types in the spindle of milling machines are discussed in Chapter 5.)

Auxiliary tools and adjustment of fixtures for clamping workpieces. When fixing the workpiece on the machine, the following rules must be observed: the position achieved during its installation must not be violated; the fixing must be such that the position of the workpiece remains unchanged; deformations of the workpiece and crushing of its surfaces that occur during fixing should be within acceptable limits.

Compliance with these rules is achieved rational choice clamping schemes and clamping forces. When choosing a scheme for fixing a part, the following considerations should be used. To reduce the clamping force, the workpiece must be installed so that the cutting force is directed to the mounting elements of fixtures 1 (support pin, pin, etc.) located on the line of action of this force or near it (Fig. 9.6).

Rice. 9.6. Installing and fixing the roller during milling:
1 - support pin; 2 - prism; Q - clamping force; D r - cutting direction

To eliminate possible shifting of the workpiece during clamping, the clamping force Q should be directed perpendicular to the surface of the setting element. In order to eliminate deformation of the part during fixing, it is necessary that the line of action of the clamping force crosses the mounting surface of the mounting elements (Fig. 9.7).

Rice. 9.7. Detail fixing scheme:
a and b are correct; c - wrong; Q - clamping force; D r - cutting direction

When fixing thin-walled box-shaped parts, to reduce the deflection of the wall, instead of the clamping force Q (Fig. 9.8, a) acting in the middle of the part, two efforts Q / 2 should be applied at points B and C (Fig. 9.8, b).

Rice. 9.8. Fixing a thin-walled part:
a - wrong; b - correct; A, B and C - clamping force application points

To reduce the crushing of surfaces when fixing workpieces, it is necessary to use in clamping devices such contact elements 1 that allow you to distribute the clamping force between two (Fig. 9.9, a), three (Fig. 9.9, 6) points or disperse it over the annular surface (Fig. 9.9 , in).

Rice. 9.9. Contact elements:
a - with two surfaces; b - with three surfaces; in - with a ring-shaped surface; Q - clamping force

On fig. 9.10 shows a diagram of the installation and fixing of the workpiece, on which the adjustable support 1 and the clamping force Q 2 are close to the surface to be machined to increase its rigidity.

Rice. 9.10. Scheme of installation and fixing of a part of low rigidity:
1 - adjustable support; Q 1 , Q 2 - clamping forces

When working on milling machines high requirements presented to the clamping tool and to threaded connections which determines their durability and safety of work.

Screwdrivers are used to secure and unscrew screws that have a slot (slot). The main requirement for screwdrivers is that the blade (blade) of the screwdriver must have parallel edges so that it freely enters the entire depth of the screw slot with a small gap.

wrenches are essential tool for milling work when fixing fixtures or workpieces on the machine table with bolts and nuts. Key heads are standardized and have a specific size, which is indicated on the key handle. The dimensions of the throat (grip) are made in such a way that the gap between the edges of the nut or bolt head and the edges of the throat is within 0.1 ... 0.3 mm. With a larger gap, the wrench can break off the nut or bolt head and injure the worker's hands. Wrenches are simple (one-size), universal (sliding) and special purpose.

With simple keys, when setting up the machine, you can screw nuts of the same size and one shape (Fig. 9.11). If a right hand grips the handle wrench 4 at a distance of 250 mm from the jaw 1 of the key and presses on it with approximately a force of 1 ... 2 kgf, then the clamping force of the nut 2 and bolt 3 will be approximately 400 ... 750 kgf. Therefore, the larger the thread diameter and the longer the wrench handle, the greater the clamping force.

Rice. 9.11. Scheme of the position of the hands when installing the workpiece on the table of the milling machine with a wrench:
a - correct; b - wrong; 1 - pharynx; 2 - nut; 3 - bolt; 4 - handle

dividing heads they are mainly used on cantilever and universal machines for fixing the workpiece and turning it on various angles by continuous or intermittent rotation. Depending on the design of the head, the workpiece circumference can be divided into equal or unequal parts. When cutting helical grooves, the workpiece is simultaneously given continuous rotational and translational motion, as, for example, in the processing of chip grooves for drills, milling cutters, taps, reamers and countersinks. Such heads are used in the manufacture of polyhedra, cutting gear wheels and sprockets, slotting, splines, etc.

According to the principle of operation, there are dividing heads limb (universal), optical, limbless and with a disk for direct division. Limbovy dividing heads apply to performance of all types of works.

The universal limb dividing head (Fig. 9.12) consists of a base 12 with tightening arches 6, in which a cylindrical body 5 is mounted. When the nuts 13 are loosened, the body 5 can be rotated around the horizontal axis counterclockwise at an angle of -5° to +95° - clockwise. The rotation of the body is controlled by a scale and vernier.

Rice. 9.12. Universal dividing head:
1 - installation center; 2 - spindle; 3 - limbus; 4 - nonius; 5 - cylindrical body; 6 - coupling arcs; 7 - dividing disk; 8 - latch; 9 - sliding sector; 10 - handle; 11 - scale; 12 - base; 13 - nuts; 14 - handle

In housing 5, a spindle 2 is mounted on bearings, at the front end of which there is a thread with a centering belt for attaching a self-centering or driving chuck and a conical hole for installing the center 1. There is also a dial 3 with divisions and a vernier 4 for direct division, and at the rear end spindle has a mandrel for change gears. The rotation of the spindle 2 is transmitted using the handle 10 with the latch 8 through gear wheels with a gear ratio equal to 1, and a worm pair k/N, where k is the number of worm starts, N is the number of teeth of the worm wheel. The handle rotation is counted using 7 holes drilled on the dividing disk. For the convenience of counting the turn of the handle, there is a sliding sector 9, consisting of rulers. With the help of the considered dividing head you can perform simple and complex (differential) division.

Direct division is carried out along the limb 3 with divisions through 1 °. The reading accuracy using the vernier H is 5". The spindle can be rotated with the handle 11 or by direct rotation of the spindle. After each rotation, the spindle is fixed with a stopper 8. In some dividing heads, instead of limb 3 with divisions, a disk with holes in a circle is installed (24; 30 and 36 holes), which allows you to divide into 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, 24, 30 and 36 parts.

A simple division is performed using a fixed stopper 4 (Fig. 9.13), on both sides of which holes are drilled along concentric circles. On one side of the disk there can be circles with 24, 25, 26, 28, 30, 34, 37, 38, 39, 41, 42 and 43 holes, and on the other - with 46, 47, 49, 51, 53, 54, 57, 58, 59, 62 and 66 holes.

Rice. 9.13. The scheme for setting up a universal limb head for a simple division:
1 - worm wheel; 2 - worm; 3 - spindle; 4 - stopper; 5 - handle; 6 - sector; 7 - dividing disk; 8 and 9 - gears; z 1 , z 2 - gears

Adjustment for differential division is used in cases where it is impossible to select a dividing disc with the required number of holes for simple division. (The method for setting up a universal limb head for differential division is described in.)

test questions

1. What is up and down milling?
2. How to set up cutting conditions on a manual console milling machine?
3. Tell us about the clamping devices used on milling machines.
4. Tell me about setup various types cutters on a console milling machine.
5. What are the types of dividing heads and what is their characteristic?
6. How is the universal limb head adjusted to a simple division?

1 The designs of installation elements and fixtures for milling machines are discussed in Ch. 5.

Milling machines are designed for processing external and internal flat, cylindrical and shaped surfaces, straight and helical grooves, threads, gears, etc.

Cutting tool- these are cutters: cylindrical, end, end, angular, keyway, shaped, etc. The types of work performed by milling are shown in fig. 5.6. The cutter operation scheme, its elements and geometry, as well as the choice of cutting modes during milling are given in Ch. 2.

Rice. 5.6. Types of work performed by milling and used cutters:
a - cylindrical with straight and helical teeth; b - end; in - disk; g - slotted (cut-off); d - terminal; e - angular; g - shaped; h - keyway (with grooving to the full depth and with pendulum feed); t - cutting depth, mm; B - milling width, mm; D s - direction of movement of the feed; D r - cutting direction; V s - feed speed

When working on milling machines use a large number of various devices that serve to install tools and fix workpieces, as well as to expand the technological capabilities of milling machines.

Tooling. The cutters are mounted on mandrels and in chucks, which, in turn, are mounted in various ways in the machine spindle.

On fig. 5.7 shows the installation of a cylindrical shell mill on a long mandrel. The position of the cutter 6 on the mandrel 3 is regulated by spacer rings 5. The cutter and the mandrel are connected with a key 7. The conical shank of the mandrel has internal thread, are inserted into the spindle hole 2 of the machine and tightened with a ramrod 1. To prevent the mandrel from turning, crackers 4 are installed in the spindle, which enter the grooves of the spindle and mandrel flange. The free end of the long mandrel is supported by suspension 8 mounted on the trunk of the machine.

Rice. 5.7. Installing a cylindrical cutter on a long arbor:
ramrod; 2 - spindle; 3 - mandrel; 4 - cracker; 5 - spacer rings; 6 - cutter; 7 - key; 8 - suspension

Shell end mills can be mounted on mandrels or directly on the machine spindle (Fig. 5.8). The cutter 1 is put on the spindle 4 of the machine with a cylindrical belt and attracted with screws 3. The torque from the spindle to the cutter is transmitted by the end key 2.

Rice. 5.8. Installing end mills on the machine spindle:
1 - cutter; 2 - key; 3 - screw; 4 - spindle

End mills are produced with conical and cylindrical shanks. Cutters with a tapered shank are installed in the machine spindle using adapter sleeves. End mills with a cylindrical shank are fixed in a chuck, which is inserted into the machine spindle with a tapered shank. The design of one of these cartridges is shown in Fig. 5.9. The cutter 1 is installed in the collet 2 and the nut 3 is fixed in the chuck body 4.

Rice. 5.9. Mounting end mills with a cylindrical shank in the chuck:
1 - cutter; 2 - collet; 3 - nut; 4 - cartridge

In the process of working on milling machines, it takes a lot of time to tighten the ramrod when attaching the tool. To reduce these unproductive costs, various quick-acting clamping devices are used.

Devices for setting and fixing workpieces on milling machines- these are various tacks, stands, corner plates, prisms, machine vices, tables and auxiliary tools, mechanizing and automating the fixing of workpieces and thereby reducing auxiliary time.

Clamps (Fig. 5.10, a) are used to fix workpieces or any fixtures directly on the machine table with bolts. Often one of the ends of the clamp 2 rests on the stand 1 (Fig. 5.10, b).

Rice. 5.10. Tacks and stand:
a - clamps for fastening the part directly on the machine table; b - tack resting on a stand: 1 - stand; 2 - tack; 3 - bolt; 4 - workpiece

If during the processing of workpieces it is necessary to obtain planes located at an angle to one another, then corner plates are used: ordinary (Fig. 5.11, a) and universal, allowing rotation around one (Fig. 5.11, b) or two axes (Fig. 5.11, in).

Rice. 5.11. Corner plates:
a - ordinary; b - universal, allowing rotation around one axis; c - universal, allowing rotation around two axes

Machine vise can be simple fixed (Fig. 5.12, a), rotary (rotation around a vertical axis, Fig. 5.12, b), universal (rotation around two axes, Fig. 5.12, c) and special (for example, for fixing shafts, Fig. 5.12, d): with manual, pneumatic, hydraulic or pneumohydraulic drive.

Rice. 5.12. Machine vise:
a - fixed; b - rotary; in - universal; g - special

Tables for installing and fixing workpieces are fixed (Fig. 5.13, a) and rotary (Fig. 5.13, b) with manual, pneumatic, hydraulic or electric drive. Turntables make it possible to process the shaped surfaces of the workpiece on the machine, as well as to apply the method of continuous milling, when, during the processing of one workpiece, already finished parts are removed and new workpieces are installed in their place. The continuous rotation of the table provides a separate drive or machine drive.

Rice. 5.13. Tables:
a - fixed; b - swivel: 1 - bracket for mounting the table on the machine; 2 - stopper; 3 - scale for reading the angle of rotation; 4 - manual turn handle

Often, on milling machines (as well as on lathes), cam-driven and collet chucks are used to secure workpieces with cylindrical surfaces (Fig. 5.14).

Rice. 5.14. Ammo:
a - cam: 1 - cams; 2 - body; 3 - bevel gear with a turnkey hole; 4 - gear rack for moving the cams; b - leash: 1 - leash; 2 - screw fastening the leash; 3 - bracket for attaching a leash; 4 - rear center; 5 - workpiece fastening screw; 6 - blank; c - collet: 1 - cartridge mounting screw; 2 - shank; 3 - collet; 4 - workpiece

A significant reduction in auxiliary time and an increase in labor productivity during milling is achieved through the use of mechanized and automated clamping devices, which, in large-scale production, are often used together with loading devices.

When working on milling machines, universal prefabricated fixtures (USP) are widely used to secure workpieces, which are assembled from ready-made normalized interchangeable parts (Fig. 5.15). After processing a batch of blanks on the machine, such a device is disassembled and new devices are constructed from its parts. Universal prefabricated fixtures can significantly reduce the time for designing and manufacturing devices necessary for fixing workpieces, which is especially important in conditions of single-piece and small-scale production.

Rice. 5.15. Universal fitting:
1 - base plate; 2 - support; 3 - mounting bar; 4 - fixing bolt; 5 - sticking; 6 - workpiece

Devices that expand the capabilities of milling machines. Dividing heads are mainly used on cantilever and universal machines for fixing the workpiece and turning it at various angles by continuous or intermittent rotation. Depending on the design of the head, the workpiece circumference can be divided into equal or unequal parts. When cutting helical grooves, the workpiece is simultaneously subjected to continuous rotational and translational motion, as, for example, in the processing of chip grooves for drills, milling cutters, taps, reamers and countersinks. Such heads are used in the manufacture of polyhedrons, cutting gears and sprockets, cutting grooves, slots, etc.

According to the principle of operation, dividing heads are divided into limb (simple and universal), optical, limbless and with a disk for direct division. Limb dividing heads 2 are used to perform all types of work (Fig. 5.16).

Rice. 5.16. Limb dividing head:
1, 2 - centers for fastening the part

The design of the limb dividing head and the methods for its adjustment are discussed in detail in Chap. nine.

Special devices that expand the technological capabilities of milling machines. There are two groups of such devices:

• that do not change the main purpose of the milling machine (additional and multi-spindle milling heads, heads for lath milling, copiers, etc.);
• fundamentally changing the nature of the work performed (grooving, drilling and grinding heads).

Some special quick-release devices mounted on horizontal milling machines are shown in fig. 5.17.

Rice. 5.17. Special devices that expand the technological capabilities of milling machines:
a - additional vertical milling head; b - a device for milling rails; c - two-spindle milling head; g - drilling head; d - grinding head; e - slotting head; w - general form machine; 1 - device for mounting on the machine; 2 - tool head; 3- end mill; 4 - trunk of the machine; 5 - machine spindle; 6 - cutter; 7 - drive motor; 8 - head body; 9 - tool slide; 10 - tool holder; 11 - grinding head spindle

test questions

1. Tell us about the tooling of milling machines.
2. What clamping fixtures are used on milling machines?
3. What kind special devices that expand the technological capabilities of milling machines, you know?

A common method of fastening the teeth-plates in the cutter body is soldering. Most often soldering is used for tools small size and complex configuration, where it is difficult or impossible to provide mechanical fastening of the cutting inserts.

But when soldering carbide inserts, tiny cracks often appear in them, causing a decrease in tool life. To avoid the appearance of cracks, the methods of soldering plates are improved, conditions are created for their uniform heating and cooling. It is not possible to completely eliminate the cracking of the plates during soldering due to the different rates of expansion and contraction during heating or cooling of the carbide plate and the body material. The difference in expansion when heated is not dangerous, since the plate is not yet connected to the body. And when the tool cools down after soldering, the plate is already "tacked" to its socket. The body and plate volumes are reduced from different speed, large stresses appear at the junction, and the fragile tool material cracks.

Therefore, they seek to replace soldering with mechanical fastening of hard-alloy plates. The durability of such tools is much higher than soldered ones.

Picture 5 - Ways of fastening the cutting inserts of the cutters

The method of fastening the plates with a cylindrical wedge and a differential screw (Fig. 5, a). A hard-alloy plate is installed in the groove of the body and fixed with a cylindrical wedge. The wedge is tightened by screwing in the differential screw on the hexagon socket. It is called a differential screw because the thread pitch in its upper and lower parts is different. Assume that the thread pitch on the screw head is 0.5 mm, and on the shaft 1 mm. Turn the screw in one turn. It will go into the case by 1 mm. At the same time, the screw head will move in the wedge thread by 0.5 mm. And since the total movement of the head must also be 1 mm, then for 0.5 mm the head will move with the wedge. Thus, the screw is driven into the body faster than into the wedge, and the wedge clamps the plate. The advantages of the differential screw are shown when the insert is changed. When unscrewed, it moves out of the body faster than out of the wedge, and therefore pulls the wedge out of the socket.

This type of mounting is compact and easy to use, but the parts must be made with high precision. When the wedge is in its seat, the axis of its hole must necessarily coincide with the axis of the body hole. Otherwise, the differential screw will tend to move the wedge to the side and the fastening will be unreliable.

Much simpler are cutters in which the wedge is fixed with an ordinary screw (rio. 5, b); this design is compact, but less convenient to use. To replace the insert, the fixing screw must be unscrewed and screwed into the tapped hole of the wedge instead. special key. This key rests against the bottom of the groove and pulls out the wedge.

Fastening with wedges and screws is used for face, disk and end mills with a diameter of at least 30 mm.

It is especially difficult to clamp a carbide insert in a disc cutter body. If the cutter is narrow, wedge and screw fastening cannot be used, and a conventional wedge may move under the action of lateral forces arising from the operation of the cutter. The method of mechanical fastening for such cutters was developed at the All-Russian Research Institute. With this method, the plates are fixed with wedges with a cylindrical bearing surface (Fig. 5, c). Such a mount is quite reliable, but difficult to manufacture.

We will tell you how to properly install the cutter on the machine in this information issue.

Milling cutter - multiflute cutting tool used for processing materials by cutting (milling) in order to remove a certain allowance for processing.

Types of cutters

Depending on the geometric parameters There are the following types of cutters:

• Cylindrical
• conical
• end
• Terminal
• Worm

Most of all cutters have a hole in their design, thanks to which it has the ability to put on a mandrel. They are called mounted.

The other part of the cutters of relatively small diameters has a shank in its design. Such cutters are called terminal. Their shank can be cylindrical or conical.

At installing the cutter on the machine the machine operator will need information about the number of the cone and the type of machine spindle, its mounting parameters. All dimensions, including the mounting flange, are standardized (GOST 836-47).

How to install a cutter with tapered and cylindrical shank

If the size of the end mill shank matches the size of the taper hole (socket) of the spindle, then in this case they are mated without any additional elements. The shank is inserted into the conical part of the spindle and fixed with a tightening screw. This method is the most optimal and simple, it is used on milling machines with horizontal and vertical installation spindle, while providing a fairly simple cutter change.

In the case when the cutter shank taper is smaller than the spindle taper, for cutter settings use special adapters.

Installation and fastening of end mills with a cylindrical shank is carried out using a collet chuck, which increases the rigidity of the fastening.

Installing the cutter in collet chuck has the following mechanism of action:

• A collet is installed in the chuck body, which moves with a cylindrical pin fixed to it. A thread is cut on the body, along which the nut moves during its rotational movement in a clockwise direction.
• The machine operator inserts the cutter directly into the hole of the collet in the chuck. And begins to tighten the nut clockwise. Under the influence of the thrust ball bearing, the pin and collet move until the cutter is rigidly fixed in it. The collet installed in the chuck allows you to securely fix the desired cutter, prevents it from breaking and breaking.

A significant advantage in the design of such a cartridge is:

• The use of a thrust bearing, which provides a significant increase in the clamping force of the cutter.
• Convenient for attaching small cutters in it.
• Quite easy to make.
• It has small overall dimensions.

When installing the cutter in the collet, you must:

• Use a collet strictly in accordance with the diameter of the tool to be fastened.
• It is preferable to install the cutter along the entire length of the collet, which will provide a more secure fit. But not less than 2/3 of the entire length.
• The choice of the size and design of the collet for fixing the cutter in it is made only in accordance with GOST 17201-71.

First of all, it must be taken into account that the diameter of the collet should correspond as much as possible to the diameter of the cutter installed in it for tighter contact.

It is necessary to take into account the fact that the collet mechanism itself is self-centering, which ensures high accuracy of tool installation and does not require additional calibration.

Therefore, after fixing the cutter in the chuck, it remains to check it for runout. For this, a dial indicator is used. Checking by this method is carried out in two cases: when installing the cutter in the spindle of a milling machine, as well as in the case of its regrinding. To control the beat, the simplest indicator is used, which is mounted on a tripod. Measurements are fixed between the teeth of the cutter along its entire length.

In the process of metal processing, the cutter can work properly if it is properly installed and operated. And its exact fixation with a runout check allows:

• improve the quality of milling;
• increase productivity;
• avoid marriage in the product;
• reduce the risk of premature wear.