Recommendations for choosing a CNC milling machine. How to choose a CNC milling machine (milling machine) for wood with your own hands Choosing a CNC machine for wood

09.02.2024

In a CNC axis drive, a gear is used to convert the rotational motion of a motor shaft into linear motion along an axis. To make it easier for you to select a CNC gear, the most widely used types of gears in CNC machines are listed below. Transmissions that are exotic for the DIY sector, such as linear servo motor and linear stepper motor, will remain outside the scope of this article for practical reasons, and the most common ones will be considered.

Screw-nut transmission

Screw-nut transmission means a pair of steel screw with trapezoidal or metric thread and a nut. This type of transmission is a transmission with sliding friction and in practice, in turn, has several varieties.

Construction stud and nut. The most budget option. The construction pin is not intended at all for use in the machine tool industry; the technical process of its manufacture is aimed at use in the construction industry, as a result of which this type of transmission has the most complete set of disadvantages - high error, low straightness, low load characteristics, low wear resistance, high friction, etc. . However, it is still used in DIY machines manufactured for educational purposes due to its low cost. If you decide at all costs to save on gear and install a construction pin, be sure to consider the possibility of replacing it with a trapezoidal screw or ball screw! Most likely, the machine on a construction pin will not live up to your hopes.
Drive screw with trapezoidal or rectangular thread. A trapezoidal thread screw is the most common type of transmission in metalworking machines in the last century and to the present day. Trapezoidal screws are produced from various types of structural carbon steels by cutting threads on a steel bar or rolling them. Knurled screws have significantly better characteristics than threaded screws. The widespread use of trapezoidal screws is due to their wide range and the availability on the market of screws of different accuracy classes, from C10 to C3. The screw nut is made of wear-resistant materials, such as polyamides (caprolon, nylon), Teflon, bronze. Correctly designed and manufactured trapezoidal gears are characterized by high wear resistance, because... friction occurs with low pressure (due to the relatively large friction surface). On many still working Soviet-made machines, the pairs have been in place since the release of the machine, and have not been changed for 30-40 years. It is also possible to use split nuts on such lead screws, which allows you to adjust the tension by compressing the nut and select the backlash that appears over time. Of the minuses, it is worth noting, oddly enough, the ease of manufacturing the screw, which automatically means the presence of many manufacturers, with a very wide range of quality indicators. Budget series of screws are made of #45 steel without surface hardening, which can lead to disruption of the straightness of the screw (in other words, small diameter screws are soft and often bend during transportation). The disadvantages and advantages at the same time include high friction in the transmission. On the one hand, this reduces efficiency; a more powerful motor is required to rotate the propeller. On the other hand, friction somewhat dampens the rotational vibrations of the screw, which can be useful when using stepper motors (see resonance of stepper motors). This effect, however, is rather weak, and other methods are needed to combat resonance. To summarize, we can say that the trapezoidal screw has not yet lost its importance as a CNC machine tool transmission and is successfully used in machine tools of all classes.
Ball screw () Ball screw, or ball screw (also called "ball screw"), is currently the de facto standard in the construction of CNC machines. A steel screw with ball raceways, induction hardened and then ground, and a specially fitted nut with balls circulating inside. As the screw rotates, the nuts roll along raceways, transmitting force to the nut body. This transmission is distinguished by high accuracy, high efficiency (80, 90% or more) and service life. Ball screws are more often used in CNC machines, since its use allows the use of lower power motors (such significant breaking forces are not required as in the case of a screw-nut transmission). The ball screw is supplied as a complete pair, does not require adjustment of the nut and often does not require processing of the ends for installation in supports - this is done by the manufacturer, i.e. Ball screws are often plug and play, whereas with trapezoidal screws, the nuts and screws are often manufactured in different locations and may require careful adjustment, without which gaps, play, increased friction, wear, etc. may occur. Ball screws are less resistant to sawdust, dust and lack of lubrication than screw-nut transmissions; if a foreign body gets in, even a very small one, the transmission can jam, because adjacent balls in the channel rotate in the opposite direction. Additional screw protection using corrugated materials is often required. Ball screws, as well as trapezoidal screws, have limitations in length - a screw that is too long sags under its own weight and when the screw rotates (the rotation speed of the screw in 5 mm increments in portal machines reaches 10-15 rps and higher) it behaves like a jump rope, which causes the machine to vibrate, and the components that fix the screw experience shock loads, their service life quickly decreases, gaps appear in the seats, which in turn increases the vibration of the machine and reduces the quality of the products produced. Experience shows that the ratio of the ball screw diameter to its length should not be less than 0.022, and it is also not recommended to exceed the screw length of 2000 mm. To eliminate the “jumping rope” effect, designs with a fixed screw and a rotating nut are used, but such units, as a rule, are much more expensive and more difficult to manufacture, and also require space, which is not always possible to implement on compact portals. If you plan to sometimes turn off the drive motors and operate the machine manually, then it is better not to use a ball screw - transmission without self-braking can cause you a lot of trouble. For information on the types of ball screws and their features, see the main article.

Gear

Gears used in CNC machines, there are 2 types

How to select a gear for a CNC machine

In order to select gear for CNC machine, the choice should be based on those characteristics that are most critical for your machine. Screw-nut transmissions are used where there are no high requirements for accuracy and speed of movement, if self-braking is required from the transmission, as well as in the case of strict budget restrictions. Ball screws have the widest range of applications; you can buy ball screws with the accuracy class, pitch, and the ability to create preload or without it that you need. The only case when a ball screw cannot be used is if self-braking is required from the transmission, however, if we are talking about braking the transmission for safety reasons (holding the spindle head), then the issue is resolved by using an electromagnetic brake on the engine, a counterweight, etc. The rack and belt are used in machines with a large working area - from 1.5 square meters and more - primarily to achieve high cutting speeds and idle movements. On machines of this size, the goal is not to achieve an accuracy of tens of microns; 0.2-0.3 mm is more than enough in most cases, so the stretchability of the belt and the accuracy of the rack and pinion gear are not an obstacle to their use.

So, if you have a large cutting machine, you should choose a rack or belt drive. If you have a desktop milling and engraving machine for educational or hobby purposes, a screw-nut transmission is suitable for you. If you are building a medium format machine for business, for production, a ball screw would be the optimal choice. After choosing the type, you should decide on specific transmission parameters.

Copying is permitted with a direct link to the source

This sophisticated equipment produces all kinds of parts from metal, plexiglass, acrylic or plastic, and wood. Their versatility lies in the fact that they are well suited for transverse planing, the formation of the most complex surfaces, in particular curved ones; perform sampling of tongues, tongues, folds, grooves, splines and mouldings.

Description of the machine

The standard equipment of the machine includes:

heavy and powerful base;
Desktop;
, with the simultaneous presence of a spindle shaft;
a set of several tools for cutting materials;
front disc brake.

The design of machine tools today includes many important devices that ensure precision processing and ease of use. It is important to know about them so that the choice of a CNC milling machine is meaningful and correct.

Don't ignore the spindle!

One of the important qualities in the operation of the spindle shaft electric motor is the ability to rotate it smoothly and evenly. When assembling, bearings of the highest accuracy class are selected, and the collet must have increased tolerances for runout and size.

There are main types of spindle cooling systems:

Liquid (it is based on the circulation of water or antifreeze in a closed circuit). One of the advantages is reliable heat dissipation. Among the disadvantages is the complex design, because the coolant must be placed in a reservoir.
Air (such cooling consists of pumping air through air intake slots in the spindle cavity). Among the advantages of the system are compactness and simplicity. There is also a downside - filters, especially for equipment processing solid wood, need to be changed frequently; they become contaminated with dust.

When choosing a spindle for a CNC machine, you should pay attention to its indicators indicated in the technical data sheet (power and rotation speed during milling), depending on how hard the materials are processed. For example, for sheet plywood the required power for processing is 800 W; a more powerful machine works on solid hardwood, light metals - copper, brass and aluminum, plastic - 1500 W; and the stone is processed at a power of 3000 - 4000 W.

Nowadays, in equipment for milling work, imported spindles are mainly used:

Italian - high-quality, operating at high speed, with smooth rotation and low runout, mainly air-cooled and at a high price.
The Chinese one has a solid cylindrical body, which is closed at the ends with covers, and bearing units are used to hold the shafts. Among the advantages - the design has a sufficient level of rigidity and minimal vibration, insensitivity to the presence of chips and dust, and affordability. Spindle models made in China, unfortunately, have a high probability of defects; it can be difficult to replace the bearings. And models with water cooling have weak anti-corrosion resistance of internal parts.

Types of Milling Machines

When choosing such equipment, one must proceed from the extent to which it corresponds to its intended purpose. Russians have a choice:

high-speed CNC automatic machines that cut and cut metals, process parts made of cardboard and wood, cope with two-layer plastic and acrylic, PVC, plexiglass and plaster, natural stone - granite and marble;
models (milling and engraving) working with sheets (maximum dimensions 2000 x 4000 x 200 mm);
engravers (from 2D modeling to 4D);
narrow-profile machines that work with one particular material - varieties of stone, plywood, wood, stainless steel or aluminum;
small portable CNC models. For example, a model of a milling machine with “Desktop 3D” is used for milling printed circuit boards, MDF and processes products with extreme precision.

In the line of equipment of the series for professionals, you can give preference to vertical and horizontal machining centers with program control; large three-, four- and five-axis CNC milling engravers, which are produced in Taiwan.

They are considered quite reliable and can be purchased (after Germany and Japan - in third position). In addition, they are profitable to purchase for both individuals and enterprises, thanks to the presence of service centers in Moscow and Tula that supply equipment, cutting tools, set up equipment and train personnel.

ATTENTION: It is not difficult to distinguish a machine from Taiwan: it has a solid cast bed (made from Brazilian fine-grained cast iron). In addition, the machine is equipped with American or Japanese bearings and imported spindles.

And if the customer is looking for a high-precision jewelry machine, the best model for this is P 0403 from the manufacturer Vector.

Furniture equipment

Woodworking and furniture production, workshops producing windows, doors and facades will not be able to function without equipment with wide functionality - CNC wood cutting machines.

In recent years, retro-style furniture has become fashionable - with elegant carved armrests, legs and other details. In this case, the technology of automated cutting of the pattern is used on a milling machine on which a numerical control is installed. It provides high precision and quality when complex wood milling is performed and a carved element is created.

With the help of such equipment, it is possible to establish production of:

wooden furniture facades and decorative consoles;
balusters, figured legs and slotted elements;
embedded carved parts;
symbols, figurines, figurines and frames of various shapes for paintings and mirrors.

Those who are limited in funds may buy an inexpensive Chinese standard CNC engraving and milling machine - SS-M1, especially for. When making facades, engraving decor and bas-relief, there is usually a lot of dust. Therefore, choose the configuration that has vacuum aspiration for dust absorption. This model has it.

Which milling machines are better? No one will give a definite answer. But there is still more trust in software working equipment. Each master has his own approach to choosing the right equipment.

And a good CNC milling machine is one that has higher accuracy, lower energy consumption, greater ease of use, and reliability in any working situation.

Three tips for making the right choice can be formulated:

Check with company managers in advance for all information about the model; materials the machine works with. If there is a video, watch it. This will help you decide.
Consult before purchasing regarding the functionality of the equipment and the range of tasks performed. The best option is to sign up for a demonstration of how the CNC machine works and don’t be shy to ask questions during operation.
When the desired model is selected, be careful at the time of purchase: check the purchased equipment for complete components. There must be a program control unit for the machine; cords with connectors of the appropriate configuration, and disks with software. Typically, the software is installed by specialists from the company that sells the machine during its setup.

Conclusion

Basically, we tried to help a person facing a choice. We figured out how to choose a milling machine (an expensive thing, and it will work for the owner for many years - with metal or wood). At least now there is plenty to choose from. It is hoped that readers will use this information to purchase a work tool.

If you are just starting a business and do not have experience in this field, choosing a CNC milling machine can confuse you - there is so much variety in the industrial tool market.

Only many years of experience and specific knowledge allow specialists to select CNC machines in accordance with the requirements for the equipment.

Many people simply get lost in this abundance, and this is not surprising - choosing the best CNC machine can be difficult even for professionals if they do not follow the latest products in the tool market, the range of which is constantly expanding and improving.

By what criteria is it better to choose a CNC machine?

Spindle

The spindle is one of the main parts of a milling machine. It depends on the spindle which cutters can be used with this particular machine, at what angles they can be fixed and how exactly to use them. The spindle drive is usually built-in - that is, the spindle is a powerful compact electric motor with a collet for clamping the cutter.

Much directly depends on the quality of the spindle - a good spindle will last a long time, constantly pleasing you with the quality of work, but a bad one can ruin not only the product, but also damage the machine itself in the event of an accident, or even injure personnel. The choice of spindle should be approached responsibly, always carefully listening to the recommendations of the machine manufacturer and paying attention, first of all, to the products of well-known and reputable component manufacturers.

Milling area

This is one of the most important characteristics of a CNC machine - the size of the milling area determines what size product the machine can process. Each narrow area of application has its own size requirements; more universal machines have an adjustable milling area, or obviously exceed the requirements for most common application cases.

The design of the platform is also important - it should not cause difficulties in securing and clearly positioning the workpiece part, otherwise serious defects are possible. When choosing a CNC milling machine for work, you need to decide in advance on the dimensions of the parts to be processed so as not to get into trouble.

Purpose of the machine

CNC machines are divided primarily according to the material they are designed to process, as well as by area of application.

Metalworking CNC machines differ from others primarily in the strength and power of their design, which allows them to work with both metal and most other materials.

To reduce wear and avoid jamming of the cutter, they are often equipped with a supply of coolant to the cutter, usually water or oil, directly into the working contact area, and many of them are equipped with a powerful air suction - a design designed to mount the bell of an industrial vacuum cleaner, to automatically remove chips from the processed material. surfaces.

Woodworking equipment

CNC machines for working with wood, as well as composites and plastics, differ little structurally from machines for working with metal, but have a slightly simpler design and lower requirements for power and strength characteristics, which is naturally due to the specifics of the material.

The cutter is cooled by air, and more often it is completely absent, since its presence is not critical. Chip removal is also usually not provided for and is carried out manually by the operator. Accordingly, the cost of such machines is usually somewhat lower, and their maintenance is simpler and cheaper, and their prevalence is greater.

Equipment for the manufacture of cabinet furniture

CNC machines designed for the production of cabinet furniture have their own characteristics - in particular, the dimensions of the milling area in them exceed those of other CNC milling machines, since the parts to be processed may have a larger area compared to other areas of CNC application.

Accordingly, a furniture CNC machine will have larger dimensions in all dimensions, as well as greater complexity and cost of the frame and guides than a similar machine for working with smaller objects. Otherwise, they differ little from machines for processing wood, plastic and composite materials.

Glass processing machines

Glass-processing CNC milling machines differ from machines for metal processing mainly in that they use special cutters with carbide, diamond and corundum working surfaces.

Milling cutters can be either specially coated or all-sintered - such components are created by baking diamond chips at high temperatures and high pressure, which gives an unusually strong and durable tool.

Also, in machines that process glass, the supply of working fluid to the area of contact of the cutter with the material is mandatory - this is due not only to the need to cool the cutter when working with such a hard material as glass, but also to the necessity of immediately eliminating waste material fragments - so that they do not interfere with further work and do not spoil the part by getting back into the place of contact between the cutter and the workpiece, on the one hand, and so that they do not get into the air that the machine operator breathes. In addition to glass, such machines can process polycarbonate, plexiglass of various compositions and other solid materials, as well as metal workpieces.

You can choose a CNC machine for working on glass based on its compliance with these mandatory criteria.

Stone processing equipment

The specifics of working with stone simultaneously require large processing areas, high hardness of the material, and increased weight of the workpieces. Also, the stone is characterized by the fact that when working with it there is a need for both constant circulation of water in the work area and the removal of crumbs and dust with a vacuum cleaner - water itself does not save from dust of the coarse fraction, characteristic of mineral materials.

Such machines can easily cope with other materials - from wood and PVC, to, often, even glass and metal, and therefore will be useful not only for manufacturers of stone products, but also for those whose professional interests are much broader.

This is, perhaps, the most advanced equipment for milling with program control, which can do almost everything in this area of production, however, it is overly powerful, bulky and expensive for most work not directly related to its purpose.

No matter how great the temptation may be to get a truly universal CNC milling machine, if your tasks do not include stone processing, consider purchasing something more specialized from the ones listed above.

Types of kinematic models of the machine

When preparing to work on a CNC milling machine, kinematic models of the machine are used, which are a software simulation of this equipment and are necessary for the correct preparation and predictability of the machine’s actions during program execution.

The kinematic model of the machine necessarily contains information about the working area, its dimensions and location relative to the stationary base of the machine, the location and possible trajectories of the working head - the cutter holder, and other physical parameters of the equipment - distances, dimensions - all that have a direct impact attitude towards the work performed by the machine.

Examples of machines and their models:

Preparing a control program

To work on CNC milling machines, CAD/CAM systems are used - software packages designed to translate data from drawings and models into a form of commands understandable to the machine.

The entered data on the size and shape of the part becomes control trajectories, which, in turn, turn into control programs in the postprocessing process.

Postprocessor

A postprocessor is a special software product that turns data on the parameters of a part into an individual program that controls the movements of the tool and/or workpiece for each specific machine.

Here you can read more about the development of kinematic models, using the example of industrial systems from Siemens.

Detailed information on working with each specific machine can be obtained on the official website of its manufacturer. This is the most reliable option and will save you from many mistakes.

Control

In some cases, when you have to work on a serious industrial machine, you can set a program for processing some more or less simple part manually, through the machine control panel. In this case, you should strictly follow the manufacturer's instructions and follow all the necessary steps sequentially.

Control panel for one of the CNC milling machines:

When creating elements of more complex shapes, it is impossible to do without the use of a computer, and many compact machines are even controlled only through a connected PC.

Multi-axis machining

CNC milling machines are divided into vertical and horizontal - according to the location of the working head, respectively - top or side, and are also divided according to the number of processing axes - into three-axis, four- and five-axis.

Accordingly, the more coordinate axes of tool movement, the more efficiently and with greater complexity the part can be processed.

Cutters used

Depending on the specifics of the work - the material, the required forms of processing and other factors, CNC milling machines use a large number of various cutters. The cutters are single-start, double-start, spherical, v-shaped, spherical cone, pyramidal radius with one or two cutting edges, engraving, cutting, etc.

Spherical and pyramidal cutters are used for deep removal of material from a part, processing corners, and creating recesses of the appropriate shape. Cutting and engraving cutters of various shapes are used for engraving, cutting parts, processing the edges of the product, and for shaping - creating a bas-relief image. Radius and fillet cutters, both convex and concave, are used for processing corners, edges of countertops and other parts, chamfering, etc. Face mills allow you to create holes, unlike drills, of any shape.

Examples of cutters used:

The variety of cutters varies from the simplest, similar to an ordinary drill or auger, to very complex ones, made of different materials and all kinds of shapes, with a different number of cutting edges. This provides a wide range of tasks they can solve.

For each material and type of work, an individual selection of cutters is required, which our specialist will help you choose.

CNC milling machines are an excellent tool that, when used correctly, can create a very wide range of products, from advertising structures to parts of other machines, from kitchen cutting boards to jet aircraft engine parts. The scope of their application is almost limitless, and the range and degree of availability are increasing every day.

Now not only a machine-building plant can afford such equipment, but also a relatively small workshop, which is good news.

Want more interesting news from the world of 3D technology?

CNC machining can baffle you with so much variety in the industrial tool market.

Only many years of experience and specific knowledge allow specialists to select CNC machines in accordance with the requirements for the equipment.

Many people simply get lost in this abundance, and this is not surprising - choosing the best CNC machine can be difficult even for professionals if they do not follow the latest products in the tool market, the range of which is constantly expanding and improving.

By what criteria is it better to choose a CNC machine?

It depends on what it will be used for. From the materials, the profile of the work, the required speed and accuracy, and the required resource. Many significant characteristics of such machines directly depend on their equipment - on the properties of their components and consumables, on design features. Let's look at the most basic ones.
The spindle is one of the main parts of a milling machine. It depends on the spindle which cutters can be used with this particular machine, at what angles they can be fixed and how exactly to use them. The spindle drive is usually built-in - that is, the spindle is a powerful compact electric motor with a collet for clamping the cutter.

Milling area

Purpose of the machine

CNC machines are divided primarily according to the material they are designed to process, as well as by area of application.

The entered data on the size and shape of the part becomes control trajectories, which, in turn, turn into control programs in the postprocessing process.

Postprocessor

Here you can read more about the development of kinematic models, using the example of industrial systems from Siemens.

Detailed information on working with each specific machine can be obtained on the official website of its manufacturer. This is the most reliable option and will save you from many mistakes.

Control panel for one of the CNC milling machines:

Cutters used

Examples of cutters used:

For each material and type of work, an individual selection of cutters is required, which our specialist will help you choose.

Now not only a machine-building plant can afford such equipment, but also a relatively small workshop, which is good news.

If you need advice on choosing a CNC machine, remember that you can always contact Top 3D Shop!

Want more interesting news from the world of 3D technology?

If you are just starting your own business and do not have experience in this field, choosing a CNC may confuse you - there is so much variety in the industrial tool market. Only many years of experience and specific knowledge allow specialists to select CNC machines in accordance with the requirements for the equipment. Many people simply get lost in this abundance; search engines are filled with queries like “choice”, “CNC milling choice”, “choose a milling machine” and “choose a CNC milling machine”. This is not surprising - choosing the best CNC machine can be difficult even for professionals if they do not follow the latest products in the tool market, the range of which is constantly expanding and improving.

By what criteria is it best to choose a CNC machine? It depends on what it will be used for. From the materials, the profile of the work, the required speed and accuracy, and the required resource. Many significant characteristics of such machines directly depend on their equipment - on the properties of their components and consumables, on design features. Let's look at the most basic ones.

Spindle

Milling area

The design of the platform is also important - it should not cause difficulties in securing and clearly positioning the workpiece part, otherwise serious defects are possible.
When choosing a CNC milling machine for work, you need to decide in advance on the dimensions of the parts to be processed so as not to get into trouble.

Types of machines

All CNC machines are divided primarily according to the material they are designed to process, as well as by area of application. Then - according to the design features and novelty of the design. The division is quite simple and, with due diligence and desire, having studied several specialized resources and decided on the budget, choosing a CNC machine will not be difficult.

Metalworking CNC machines differ from others primarily in the strength and power of their design, which allows them to work with both metal and most other materials.

Equipment for the production of cabinet furniture

Glass processing machines

Glass-processing CNC milling machines differ from machines for metal processing mainly in that they use special cutters with carbide, diamond and corundum working surfaces. Milling cutters can be either specially coated or all-sintered - such components are created by baking diamond chips at high temperatures and high pressure, which gives an unusually strong and durable tool. Also, in machines that process glass, the supply of working fluid to the area of contact of the cutter with the material is mandatory - this is due not only to the need to cool the cutter when working with such a hard material as glass, but also to the necessity of immediately eliminating waste material fragments - so that they do not interfere with further work and do not spoil the part by getting back into the place of contact between the cutter and the workpiece, on the one hand, and so that they do not get into the air that the machine operator breathes. In addition to glass, such machines can process polycarbonate, plexiglass of various compositions and other solid materials, as well as metal workpieces.

You can choose a CNC machine for working on glass based on its compliance with these mandatory criteria.

Stone processing equipment

CNC milling machines for stone work are designed for engraving and making complex volumetric bas-reliefs on hard materials such as natural stone of various types - granite, marble, sandstone, as well as on artificial stone slabs made of granite chips with polymer. The specifics of working with stone simultaneously require large processing areas, high hardness of the material, and increased weight of the workpieces. Also, the stone is characterized by the fact that when working with it there is a need for both constant circulation of water in the work area and the removal of crumbs and dust with a vacuum cleaner - water itself does not save from dust of the coarse fraction, characteristic of mineral materials.
Such machines can easily cope with other materials - from wood and PVC, to, often, even glass and metal, and therefore will be useful not only for manufacturers of stone products, but also for those whose professional interests are much broader.

These are perhaps the most basic points that you need to be aware of when choosing a CNC milling machine. And even if at first it seems that if you need to buy a CNC milling machine, the choice is not easy, it’s not so scary. In other articles we will talk in more detail about the specifics of working with each type of CNC milling machines and their design, this can also help with the choice, so don’t miss new publications.