Metal milling: classification, technology features

Let's say you have a working CNC machine that you just purchased, but don't yet know enough about it. Let's now assume that this is a CNC milling machine for metal, and that first of all you will be interested in milling metal that can be easily processed.

Chances are, you're itching to start milling all sorts of cool parts, building a tool magazine, or maybe assembling a Colt 1911 pistol. You can build almost anything with CNC, and you're full of ideas to get started on your favorite projects.

Features and purpose of the router

All elements of the machine are attached to a massive base; inside it is the main working part - the spindle, which rotates the milling cutter, which performs boring, drilling and tapping operations.
The electric motor ensures the duration of the milling process and allows you to adjust the rotation speed of the cutting parts of the device.

Woodworking units are used both for industrial purposes and at home.

Domestic applications include:

• installation of accessories for doors and locks;
• creating wood carvings;
• selection of grooves and formation of holes;
• adjustment of the outer layer of the cladding board;
• parquet production;
• side and profile finishing of baseboards, floorboards;
• preparation of construction timber;
• tying cabinet furniture and doors;
• creating window blocks.

Milling of titanium products

When processing titanium using milling equipment, it is necessary to take into account the fact that this metal has low thermal conductivity. Because of this, the processing process is complicated.

To make it easier to work with titanium and produce high-quality parts, it is necessary to take into account the opinion of experienced metalworking masters:

1. When machining titanium, high-speed cutters are used.
2. First, remove a large layer, smoothly moving to a thin one.
3. The cutters must have a large number of teeth.
4. During operation, observe the change in sharpening of the cutting part.
5. After each pass, make a chamfer at an angle of 45 degrees.
6. You need to start processing titanium in an arc.
7. The diameter of the cutter should be 30% less than the diameter of the groove.

Before working with titanium, you need to make sure that the engine power is sufficient to process durable types of metal. It is necessary to inspect the cutter in advance for defects and check the tension of the belts on the engine.

Milling and boring of complex titanium products Milling of metals is one of the most famous processes in metalworking. It can be produced on mechanical machines and CNC equipment. However, when working with programmable machines, it is necessary to choose an experienced operator. Otherwise, the equipment will not function normally.

Operating principle of milling machines

Almost all milling machines operate on the same principle. The only differences can be in their functionality.

Basic elements of a milling machine

The main structural elements of such machines are: a supporting frame, a work table, clamping elements, a collet and a collet chuck in which the working tool is fixed, a portal with a spindle fixed to it, which can move, and a drive electric motor.

The working tool of any milling machine is a cutter, the design and dimensions of which depend on the configuration of the part to be processed. The working tool is fixed in the collet chuck using a shank, and rotation is transmitted to it from the drive electric motor through a gear system. The main purpose of the cutter is to remove an excess layer of metal from the workpiece, which, in fact, is the essence of processing on such a machine.

The machine spindle is placed on a movable portal, the movements of which are controlled by special controllers in the case of CNC equipment. The electronic system of such equipment includes CNC (computer numerical control) controllers, auxiliary system elements and connecting parts. The operating principle of CNC machine models is as follows: a special program reads the drawings of the part that needs to be obtained as a result of processing, generates electronic commands that are transmitted to the working part of the machine.

Widely universal machines, which are a hybrid of horizontal and vertical models, deserve special attention. Their design also includes a collet, collet chuck and clamps, but the gearbox of such machines transmits all movements from a single electric motor. Their distinctive feature is the presence of a manual mode, with which you can control the operation of the running unit.

Example of a kinematic diagram (cantilever milling machine)

Additional elements include a five-axis metal milling machine and engraving equipment. Such equipment is equipped with additional clamping elements that allow you to install an engraver on it. The tool of such equipment rotates due to the cardan shaft, with which it is directly connected to the electric motor.

The simplest in design are manual metal milling machines. Such equipment has low power, and its design consists of a collet with a collet chuck, a rotor, a drive head and an electric motor. Naturally, the functionality of such a machine is also limited: it can be used to perform only the simplest milling operations.

https://youtube.com/watch?v=I8guYo1rGyo

The service life of a manual milling group machine is also low and amounts to no more than 10,000 hours. The weakest components in such equipment, which are the first to fail, are the collet and collet chuck, clamps, attachment and spindle. But its low reliability and durability are fully compensated by its low cost. It makes sense to purchase it if you plan to use it irregularly.

Cantileverless milling machines

They have a spindle that makes vertical movements, and the movements of the milling table resemble a cross (they move longitudinally and transversely). This trajectory of movement of the work table determined the second main name for equipment of this type - milling machines with a cross table. The peculiarity of such units is that they are not a cantilever base, but a rigid base for installing the workpiece; A common purpose is milling large-sized parts of significant mass.

This is interesting: Making a cyclone filter for a vacuum cleaner with your own hands

Safety precautions

Although all modern machines are necessarily equipped with protection, divided into a number of elements, compliance with basic labor protection instructions is still mandatory. The protective parts themselves must certainly be placed in the correct positions. Their serviceability is checked in any case before starting work and after any long break. Do not work in poor visibility or during any sudden deterioration in health.

A milling machine is serious equipment, and you shouldn’t allow just anyone into it. You must be of legal age and be willing to obtain a 2nd level in electrical safety (this is the minimum). A first aid kit and a fire extinguisher must be available at the workplace. You need to master each machine model very carefully from scratch. If we are talking not about home conditions, but about an enterprise, then additional instruction is certainly required.

Wood shavings must be removed regularly. Its excessive accumulation threatens a fire. The milling machine must be grounded, as well as all the wires feeding it. You can work with workpieces only after checking their fastening. Cutting parts with chips and deformations, with cracks and burrs must be replaced.

Various models

At industrial enterprises, in workshops and in specialized educational institutions, different types of machines are used. The classification of milling devices is based on their design features and operating principle. The most common are the types of milling machines discussed below.

Universal models with rotary table

Allows the production of large-sized parts. This can be cutting along the horizontal and vertical axis or screw cutting of the material.

The design of such a machine has a number of features - the main components and gearbox are located inside the frame, and the console and working surface move in different directions.

All kinds of cutters are suitable for a horizontally located spindle, for example, cylindrical, disk and angular. Additional equipment can be placed on the working table of a milling machine, which will expand its technical capabilities.

Horizontal milling machine

It is easy to operate and maintain. This is a reliable device that is widely used in many workshops. Its design does not have a rotating part - during operation the table moves parallel and perpendicular to the spindle axis.

End, cylindrical, face, corner and shaped milling cutters can be used as working tools. The working units are located on the frame, and the gearbox that drives the spindle is located inside.

Widely versatile

This milling machine is a multifunctional device. It has an additional spindle part that can be rotated at any angle using a special retractable trunk.

Overhead elements are mounted on it, for example, cutters or drills, which allow not only milling, but also various operations. For example, drilling or turning. With the help of a retractable cutter you can perform any metal work.

Simultaneous actions with two knives increase labor productivity, so such machine models are suitable for use not only in private workshops, but also in industry.

Vertical cantilever milling machine

Designed for internal and external processing of parts with different types of surface. Its spindle rotates around a vertical axis and is suitable for working with face, end and key cutters and milling heads.

In many advanced models, it can move and take a horizontal position relative to the part. The dimensions of the main components of the device, the power of the electric motor and the distance of greatest movement of the table depend on the size of the vertical console milling machine.

Cantileverless milling machine with cross table

Capable of performing complex operations at high speeds. Unlike a vertical metal milling machine, it can process massive parts. This is due to the design features of the device, which differs from standard models.

There is no console, the movement of the worktable is carried out on rigid frames, and the spindle head slides along rack-mount guides. In addition to its main functions, it copes with the tasks of the gearbox.

Carbide face, end and cylindrical cutters are suitable for this device. Basic and auxiliary movements can be performed either manually or automatically.

Application of an electric milling machine

Working with a manual wood router helps to carry out the following carpentry operations:

1. Processing of flat and shaped surfaces, edge profiling of platbands, skirting boards, cornices, glazing beads.
2. Formation of technological and shaped recesses (grooves, ridges, etc.).
3. Making through and blind holes.
4. Cutting complex parts from wood and copying them.
5. Applying inscriptions, drawings, patterns on the surface (engraving).
6. Inserting locks and hinges on doors.
7. Making a tenon joint. This is a complex process requiring special skills, which results in a highly durable assembly of wooden products.

Depending on the type of work performed with a manual wood router, video lessons of which can be viewed at the end of the article, you will need the following equipment:

• Milling cutter
• Jigsaw
• Chipboard
• Electric drill and drill bits
• Templates
• File
• Protective clothing and respirator.

With the help of such a tool, a novice craftsman can bring old furniture back to life and carry out small carpentry and decorative work with wood around the house.

Types of equipment

Regardless of the type, all milling machines operate on the same principle. They are classified based on differences consisting in the presence of additional elements that increase their functionality. For example, some installations are equipped with devices in the form of a slotting head, a device for cutting combs, etc.

https://youtube.com/watch?v=yjV5dwtuREs

Vertical milling units

A vertical milling machine allows you to process all existing types of metals and perform drilling operations. Such units are available in two versions:

• console;
• non-console.

The lack of a console structure in a vertical milling machine is compensated for by installation on the base of guides. It is along them that the desktop moves. The spindle head contains a gearbox that regulates its rotation speed. In cantilever installations, movement of the sleeve and head is possible along the axis.

Horizontal milling machines

Horizontal milling machines are characterized by a horizontal spindle arrangement and are designed for processing large-sized elements. The ability to use different types of cutters allows you to carry out a wide variety of operations. The standard package does not include only a device for operations with screw surfaces.

The horizontal milling machine is installed on a table. All mechanisms of the unit are located at its base. Only the gearbox is located inside.

Drilling and milling units

This type of milling machine differs from its counterparts by the presence of a drilling and milling head. This feature makes it possible to process inclined and corner surfaces, as well as grooves of oversized parts. The rotation of the working head can be carried out in opposite directions.

Description of universal type equipment

A universal milling machine is designed for processing any metal elements, regardless of their configuration. For this reason, such units are most in demand in private workshops. They are purchased by small businesses engaged in repairs.

The use of universal type milling machines is justified when it is necessary to perform any actions with large parts. They can be installed horizontally or vertically. The spiral-shaped surface will not become an obstacle.

This is facilitated by the presence of horizontal and vertical guides along which the console and desktop move. Important components and mechanisms of the unit are securely hidden in the inside of the base.

Capabilities of tabletop units

Tabletop milling machines are installed in home workshops, educational institutions and production shops that do not specialize in performing work of this kind.

A distinctive feature of desktop metal milling machines is their versatility. The standard equipment includes various types of cutters, allowing you to process a wide variety of workpieces. With the help of such a device, it will be possible to perform other operations, which include drilling, threading, etc.

CNC units

This category includes:

• milling machines with numerical control;
• numerically controlled machining centers;
• desktop mechanisms with numerical control.

CNC milling machine

The operation of CNC equipment is controlled by a special computer program. Therefore, during the processing process, the possibility of human factor manifestation is excluded. And the units themselves are highly expensive and are in demand only at large industrial enterprises specializing in the production of a certain type of parts.

The desktop version of CNC milling machines deserves special attention. Although they are small in size, they can be used to give the workpiece any shape. Desktop CNC machines allow you to perform a variety of technological operations with metal, including boring, drilling and countersinking.

Highly versatile devices

This metal milling machine is equipped with an additional working head. But the main feature is its mobility, which allows you to work with the workpiece, placing it at any angle.

For processing metal elements with a complex configuration, it is possible to install an overhead head on a rotating spindle. There are also non-console models with a carriage, for the movement of which horizontal guides are provided.

Review of manufacturers

Domestic

The main advantage of domestic machines is their availability. In addition, many years of experience of some companies allows them to provide high-quality products on the market, no worse than those produced in Germany and Japan.

Home master

The machines from this manufacturer are of high quality and have been on the market for quite a long time. Equipment of this brand is often used in school classrooms and small workshops. Such equipment can completely replace several highly targeted units, thereby saving money and preserving free space inside the workshop.

Craftsman

This lathe can be used to perform various types of processing of products made from metal, plastic or wood. The device is available in two versions:

1. With feed drive, milling device and wood processing unit.
2. With manual longitudinal recoil of the caliper.

The first option makes it possible to perform turning and drilling, and the second - turning, milling, planing, sawing and drilling work. You can improve and expand the functionality of the machine using additional elements.

Caliber

This company has been selling tools since 2001. A wide range of models allows you to choose the model you need. In the event of a breakdown, the company’s specialists will promptly diagnose and identify faults, and subsequently correct them. The machines are offered at reasonable prices and many products come with a guarantee.

China and other countries

China's bad reputation as a manufacturer of low-quality goods and rip-offs is long gone. Now it is a supplier and manufacturer of the best performance and quality products in the world.

Optimum

Machines of this brand are produced in Germany. This brand produces not only large lathes, but also miniature ones, which are known and highly valued by many specialists throughout Europe. The most famous models are D140x250, D210x400, D250x550. They are equipped with a CNC system.

Corvette

This company provides products at low prices. Many customers note the good quality of the goods provided. Since 2009, we have been selling machines. Machines are available, both large-sized and small-sized. When selling wholesale for an enterprise, a large discount is given.

JET

Tabletop lathes of this brand have been on the market for more than 50 years. They are produced by the Swiss company JET, which has become very popular among home craftsmen and craftsmen. Despite the fact that at the moment some components are manufactured in China, their quality does not deteriorate.

These units have earned the trust of several generations of users due to their high quality, precision and processing efficiency. There are no problems with them when working, their maintenance is simple. The most popular and best-selling models are: BD-3, BD-7, BD-8A.

Proma

The company has been on the market for 20 years. All types of machines are sold, including custom ones. The company's products are constantly being improved and modernized, taking into account the needs and demands of consumers.

DIY

The tabletop unit of this company is a compact turning device, which is produced according to uniform technical documentation by several Chinese manufacturers.

Stalex

The company focuses on the sale and service of metalworking equipment. All goods are always in stock, which is noted by numerous buyers.

Zenitech

The company sells mainly large-sized machines, but there are also several models of small-sized machines. There is always a hotline, by calling which you can ask questions and clarify all the nuances.

FDB MASCHINEN TURNER

Many buyers are put off by the somewhat inflated price of the product presented by this company. But all lathes are of high quality and come with a guarantee. Several times a year there is a promotion where the discount can be 30,40 or even 50 percent.

METALMASTER

METALMASTER equipment is developed and constantly improved in cooperation with German engineering technicians. The production of machines is carried out at world-famous factories.

Task

Generally speaking, sandwiches and salads are made “in a hurry”; a romantic dinner can be whipped up in a hurry, but not a machine. However, I included this phrase in the title of the article. Why? I'll try to explain.

“In a hurry” this means technologically for home production. Those. the machine must be designed so that it can be manufactured using a minimum set of the most common metalworking tools. Literally, if you have in your arsenal a jigsaw with a metal file, a drilling machine, tap dies and a file, then this should be enough. At worst, a simple hacksaw and a drill will do.

Some people will say: “Well, you’ve gone too far, comrade!” This doesn’t happen,” and he will be right. That really doesn't happen. Because if milling work can be eliminated completely, then we cannot do without basic turning work, which means there should be very little of this work, everything else should be done by hand, in the kitchen.

When setting yourself such a task, you need to understand well that your plans can only be achieved if you widely use purchased components and standard aluminum profiles. Guides - the cornerstones of a portal engraving and milling machine - will also have to be purchased, and they are expensive. So, “quickly” does not mean cheap!

One final thought. “In a hurry” is associated with the concepts of simple and fast. If you can agree with the definition of “simple,” then it’s unlikely to work quickly. The production of even simple parts can take an indefinite period, but as they say, “patience and labor will grind everything down.”

Let's summarize:

• For milling balsa, plywood, wood, plastics and thin (up to 2 mm) aluminum alloys.
• On linear ball guides and timing belts.
• The working field is at least 1000x300x90.
• Positioning resolution is no worse than 0.1 mm.
• Positioning speed no less than 2 m/min.

Advantages of portable (desktop) equipment

Portable equipment has several distinct advantages:

1. Takes up a small amount of space. Suitable for small rooms with little free space.
2. It is possible to perform a variety of technological operations: engraving, milling, drilling and boring, end processing and grooving. The functionality is not much inferior to large industrial models.
3. The compact model produces less noise and practically does not vibrate.
4. To connect, a common 220V network is sufficient.
5. Light weight equipment can be moved around the workshop as needed. The ease of transportation and mobility of the device allow it to be used in the most convenient places. If necessary, you can transport it from one workshop to another at minimal cost.

An important advantage of tabletop machines is their low cost. Now such equipment is used even in large industries. Its only disadvantage is the limited permissible size of processed workpieces, which is an order of magnitude smaller than that of industrial units.

How to choose

There are several main functional features that you should pay attention to when choosing a machine for working in your home workshop

In this case, it is important to take into account what work will be performed on it, the required size of the work table, the power and speed of the spindle, and the permissible processing speed

Guides

The direction of spindle travel directly depends on their location. Tabletop machines are mainly equipped with sliding guides or a polished shaft, as the most budget option.

Motor power

This parameter determines which metals the master can work with. For workpieces made of hard alloys and high-alloy steel, a more powerful electric motor is used than for working with soft alloys.

Noise level

If the workshop is located at home, then it is important that the noise level from the operating unit does not disturb the neighbors too much. Therefore, it is better to choose equipment with the lowest noise level possible.

Additional and protective devices

Despite the standard design of a tabletop metal milling machine, many models are equipped with additional devices and various safety features

Particular attention should be paid to the presence of protective shields and a system that catches chips

Cooling system

During the working process, both the cutter itself and the surface of the workpiece are actively heated. Cooling systems can be water or air. If there is no cooling system, the technician will have to regularly stop the equipment to allow it to cool. Otherwise, you may break the tool or damage the workpiece.

Modern innovations in individual production

In the home workshop, modern craftsmen, commissioned for large enterprises, process parts according to the attached drawings. Such part-time work is also beneficial for enterprises: there is no need to use additional technological equipment in the workshop to perform routine operations.

The home craftsman carries out work under a contract with the customer; he solves problems of delivery of blanks and parts independently. As a result, the overhead costs of the main production are reduced. The workplace is created by the contractor himself.

To organize the production of income, it is enough to create an individual enterprise (IE) in order to have official status (financial calculations are simplified). Currently, there are enough such organizations; they carry out significant volumes of orders.

Which designs to choose?

Not everyone can afford to purchase, say, a CNC machining center for the production of small-scale parts at home, a format-type machine or for turning. But a homemade CNC unit, made with your own hands, is real. The assembled device in capable hands will demonstrate examples of correct processing of parts.

When assembling the mechanics of programmable machines, homemade linear guides are usually used, since there is no need for devices with circular motion

Let us pay attention to some of the designs used in this case.

Galvanized or chrome-plated pipes

They come with different diameters and can be used as rods when installing low-power devices - surface grinders, drilling or lathes. The bronze bushing moves along a polished cylindrical rod. Sometimes a support is made without it. Pipes have low prices and are easy to process. Although there is a minus: a short resource (the protective layer wears off after 15-20 penetrations, after which the steel wears out more intensively); there is no required level of strength under high loads.

Fraser

An effective router is one in which the guide mechanism is made from a used dot-matrix printer or Yantar typewriter. With this option it will last a long time. There is no need to look for very wide bearings; their internal diameter should be equal to the diameter of the bolts.

Furniture rods

The problem of mechanics for CNC machines can be solved properly with the help of furniture rods. Moreover, homemade products using them guarantee thorough processing on woodworking, belt sanding equipment, and even a low-power milling machine. Furniture components are cheap, although they have a short resource.

Polished shaft

Inexpensive and frequently used type of guide. The essence of the treatment is to inductively harden the top layer, which helps to increase the service life and reduce the intensity of the wear process. The shaft is then polished and the carriage moves with minimal friction.

Homemade

It is often practiced to install homemade guides using what is available. For example, you can use angle steel, bearings, nuts and bolts.

IMPORTANT! Do not take aluminum, in this case you need to be prepared to frequently replace the part. The tracks in it are eaten away by the ball bearings of the carriage. It is better to give preference to a steel corner

If the mechanism is expected to be used intensively, it is better to harden and polish it to reduce friction on the bearings

It is better to give preference to a steel corner. If the mechanism is expected to be used intensively, it is better to harden and polish it to reduce friction on the bearings.

Stocks

When assembling a small home machine, they sometimes use car strut rods from a domestic car as guides. They are durable and made of high quality metal. This will significantly reduce the cost of components.

There is also this option: aluminum busbars from the switchgear of a transformer substation with pressed-in copper-graphite bushings from a MAZ starter. And the moving units are made from pneumatic valves, which are used to control pneumatic cylinders.

When making guides and carriages for CNC with your own hands (roller or ball), you must use the following expected criteria:

• saving specified parameters;
• smooth linear movement of carriages;
• efficiency;
• low friction.

NOTE! Some craftsmen advise doing without bushings in machine mechanics. This option is possible, but it is fraught with deterioration of the manufactured products, and the service life of the installed rod device will be reduced

Tips and tricks

CNC lathes are controlled by starting and stopping the motors. A stepper motor should be installed to feed each direction:

• spindle rotation;
• longitudinal movement of the caliper;
• lateral movement of the tool holder.

If there are other automatic feeds, each of them is connected to its own motor.

A CNC machine, even a homemade one, requires certain operating and storage conditions:

• room temperature from +10 to +25 degrees;
• humidity below 80%;
• stable voltage.

Electronics and electrical equipment are sensitive to voltage fluctuations. For stable operation of a CNC machine, it is necessary to install a voltage stabilizer.

Machine tools in Voronezh from Rosta LLC: decent quality at a competitive price

We offer a wide range of machines for working with metal from domestic manufacturers at prices several times lower than their imported counterparts. Russian products are not inferior to foreign ones either in quality or functionality.

In our catalog you will find both manual and automatic or semi-automatic equipment options that will help you process the most complex sketches from any material.

For detailed information about the range, discounts and delivery conditions, please contact us by phone. Our managers will provide you with detailed advice and help you place your order.

Popular models of narrow specialization

Milling cutters designed to perform a narrow range of tasks and have a limited set of functions to optimize a certain type of material processing.

Makita MT M3700

Characteristics:

• type – edge;
• speed – 35 thousand rpm;
• power – 530 W;
• cutter stroke depth – 42 mm;
• collet size – 6 mm;
• cable – 2 m;
• weight – 1.4 kg;
• cost – 5349 rub.

A tool with easy milling depth adjustment, good performance and low cost. Equipped with a comfortable rubber-coated handle, it can perform up to 35 thousand rpm.

Advantages:

• price;
• build quality;
• light weight;
• ergonomics.

Flaws:

• no spindle lock;
• low power.

BOSCH GKF 550 Professional

Characteristics:

• type – edge;
• power – 550 W;
• collets included – 6 mm;
• speed – 33 thousand rpm;
• weight – 1.4 kg;
• price – 5290 rub.

A unit with stable support for milling depth. The 550 W motor helps you cope with many types of finishing and carpentry work. The ergonomic body ensures ease of use. Optimized ventilation reduces device heating.

Advantages:

• ease of use;
• ease.

Flaws:

• no cutters included;
• there is no protection against accidental activation.

Makita 3709

Characteristics:

• type – edge;
• speed – 30 thousand rpm;
• power – 530 W;
• cutter stroke – 40 mm;
• collets in the set – 6 mm;
• cord – 2.5 m;
• weight – 1.5 kg;
• cost – 5931 rub.

Edge router for forming grooves and holes of various shapes in composite, wood, plasterboard, and ceramic products. High speed of rotation makes it possible to interact with compacted materials. The transparent plastic platform allows you to clearly see the element being processed.

Advantages:

• convenient depth regulator;
• good equipment with limiters and stops;
• high power and speed.

Flaws:

• there is no stopper on the shaft;
• there is no depth limiter;
• no soft start.

Main types of cutters

There are three criteria by which classification takes place:

• In shape, for example, cylindrical, conical, spherical, disk.
• By purpose: end, cutting, slotted, grooved.
• According to the material they process. In this case, we are interested in those that are intended for metal processing.

Structural differences

Structurally, they differ into the following types:

• Annular or core drills. They are needed to produce holes with higher accuracy and speed increased by 4 times compared to conventional drilling.
• Worm - touch the steel with several cutting edges at the same time.
• Shaped with pointed or backed teeth. They have two rows of blades, and the second subtype is distinguished by the presence of sharp edges on the inner end side.
• End - for creating grooves and ledges.
• Corner - excellent for processing curved surfaces and corners.
• Cylindrical with helical or straight teeth. The first are universal, the second are only for direct coatings.
• End - monolithic or with replaceable plates.
• Disc - designed, as a rule, for cutting steel sheets and cutting grooves.

Organize by base size

Standards regulate the basic parameters of equipment characteristic of this type. For a group of turning and cylindrical grinding machines, this is the maximum size of the part for processing.

For milling machines, the main consideration is the size of the work table for installing workpieces and equipment. For cross-planing machines, the basic value is the stroke of the slider.

A set of machines for one type of processing, with similar kinematics and structure, but differing in main dimensions, is called a size range. For example, according to the standards, gear hobbing machines have 12 standard sizes with a maximum workpiece diameter for processing from 80 mm to 12.5 thousand mm.