Being aware of what is complex technical and electronic device, many craftsmen think that it is simply impossible to make it with their own hands. However, this opinion is erroneous: you can make such equipment yourself, but for this you need to have not only its detailed drawing, but also a set of necessary tools and relevant components.
Processing of duralumin blanks on a homemade desktop milling machine
When deciding to make a homemade CNC machine, keep in mind that this can take a significant amount of time. In addition, certain financial costs will be required. However, not being afraid of such difficulties and having the right approach to solving all issues, you can become the owner of affordable, efficient and productive equipment that allows you to process workpieces from various materials With a high degree accuracy.
To make a milling machine equipped with a CNC system, you can use two options: buy a ready-made kit, from which such equipment is assembled from specially selected elements, or find all the components and assemble a device that fully meets all your requirements with your own hands.
Instructions for assembling a homemade CNC milling machine
Below in the photo you can see made with your own hands, to which is attached detailed instructions for manufacturing and assembly, indicating the materials and components used, accurate “patterns” of machine parts and approximate costs. The only downside is the instructions English language, but it is quite possible to understand the detailed drawings without knowing the language.
Download free instructions for the manufacture of the machine:
The CNC milling machine is assembled and ready to go. Below are some illustrations from the assembly instructions for this machine.
"Patterns" of machine parts (reduced view) Beginning of machine assembly Intermediate stage Final assembly stage
Preparatory work
If you decide that you will design a CNC machine with your own hands without using a ready-made kit, then the first thing you need to do is to opt for circuit diagram, on which such mini-equipment will work.
For the basis of CNC milling equipment, you can take the old drilling machine, in which the working head with a drill is replaced by a milling head. The most complex thing that will have to be designed in such equipment is a mechanism that ensures the movement of the tool in three independent planes. This mechanism can be assembled on the basis of carriages from a non-working printer; it will ensure the movement of the tool in two planes.
It is easy to connect software control to a device assembled according to such a concept. However, its main drawback is that it will be possible to process on such a CNC machine only workpieces made of plastic, wood and thin sheet metal. This is explained by the fact that the carriages from the old printer, which will provide movement cutting tool, do not have a sufficient degree of rigidity.
In order for your homemade CNC machine to be able to perform full-fledged milling operations with workpieces from various materials, a sufficiently powerful stepper motor must be responsible for moving the working tool. It is not at all necessary to look for a stepper-type engine, it can be made from a conventional electric motor, subjecting the latter to a slight refinement.
The use of a stepper motor in yours will make it possible to avoid the use of a screw drive, and functionality and the characteristics of home-made equipment will not get worse from this. If you still decide to use carriages from the printer for your mini-machine, then it is advisable to pick them up from a larger model of the printing device. To transfer force to the shaft of milling equipment, it is better to use not ordinary, but toothed belts that will not slip on the pulleys.
One of the most important components of any such machine is the milling mechanism. It is its manufacture that must be given Special attention. To properly make such a mechanism, you will need detailed drawings, which will need to be strictly followed.
CNC milling machine drawings
Let's start assembling the equipment
The basis of home-made CNC milling equipment can be a rectangular beam, which must be securely fixed on the rails.
The supporting structure of the machine must have high rigidity, it is better not to use welded joints, and you need to connect all the elements only with screws.
This requirement is explained by the fact that the welds are very poorly tolerated by vibration loads, which the supporting structure of the equipment will necessarily be subjected to. Such loads will eventually lead to the fact that the frame of the machine will begin to collapse over time, and changes in geometric dimensions will occur in it, which will affect the accuracy of the equipment settings and its performance.
Welded seams when mounting a homemade frame milling machine often provoke the development of play in its nodes, as well as the deflection of the guides, which is formed under severe loads.
In the milling machine, which you will assemble with your own hands, a mechanism must be provided to ensure the movement of the working tool in a vertical direction. It is best to use a screw gear for this, the rotation of which will be transmitted using a toothed belt.
An important detail of the milling machine is its vertical axis, which for a homemade device can be made from an aluminum plate. It is very important that the dimensions of this axis are precisely adjusted to the dimensions of the device being assembled. If you have a muffle furnace at your disposal, then you can make the vertical axis of the machine with your own hands, casting it from aluminum according to the dimensions indicated in the finished drawing.
After all the components of your homemade milling machine are prepared, you can begin to assemble it. This process begins with the installation of two stepper motors, which are mounted on the equipment body behind its vertical axis. One of these electric motors will be responsible for moving the milling head in the horizontal plane, and the second - for moving the head, respectively, in the vertical plane. After that, the remaining components and assemblies of home-made equipment are mounted.
Rotation to all components of home-made CNC equipment should be transmitted only through belt drives. Before connecting the system to the assembled machine program control, you should check its performance in manual mode and immediately eliminate all identified shortcomings in its operation.
You can watch the assembly process on the video, which is easy to find on the Internet.
Stepper motors
In the design of any CNC milling machine, there are necessarily stepper motors that provide tool movement in three planes: 3D. When designing a homemade machine for this purpose, you can use electric motors installed in a dot matrix printer. Most older models of dot matrix printers were equipped with electric motors with fairly high power. In addition to stepper motors from an old printer, it is worth taking strong steel rods, which can also be used in the construction of your homemade machine.
To make a CNC router with your own hands, you will need three stepper motors. Since there are only two of them in a dot matrix printer, it will be necessary to find and disassemble another old printing device.
It turns out a big plus if the motors you find have five control wires: this will significantly increase the functionality of your future mini-machine. It is also important to find out the following parameters of the stepper motors you found: how many degrees it rotates in one step, what is the supply voltage, and also the value of the winding resistance.
The drive design of a homemade CNC milling machine is assembled from a nut and a stud, the dimensions of which must first be selected according to the drawing of your equipment. To fix the motor shaft and to attach it to the stud, it is convenient to use a thick rubber winding from an electric cable. Elements of your CNC machine, such as clamps, can be made in the form of a nylon sleeve into which a screw is inserted. To make such simple structural elements, you will need a regular file and a drill.
Electronic filling of equipment
Your do-it-yourself CNC machine will be controlled by software, and you need to choose the right one. When choosing such software (you can write it yourself), it is important to pay attention to the fact that it is efficient and allows the machine to implement all its functionality. Such software should contain drivers for controllers that will be installed on your mini milling machine.
In a homemade CNC machine, the LPT port is mandatory, through which electronic system control and connect to the machine. It is very important that this connection is made through the installed stepper motors.
When choosing electronic components for your do-it-yourself machine, it is important to pay attention to their quality, since the accuracy will depend on this. technological operations that will run on it. After installing and connecting all the electronic components of the CNC system, you need to download the necessary software and drivers. Only after that, a test run of the machine follows, checking the correct operation of the machine under the control of downloaded programs, identifying shortcomings and promptly eliminating them.
In preparation for the design of the technological process, a detailed analysis of the drawing is carried out to identify the missing dimensions and structural and technological data. Missing dimensions and other data can be obtained from the designer, from assembly drawings, or by geometric constructions of the part outline.
In order to facilitate the preparation of NC, dimensioning in the part drawing must satisfy the requirements of programming.
Since processing on CNC machines is carried out according to commands that determine the coordinates of the trajectory points in a rectangular coordinate system, the dimensions in the drawings must also be specified in a rectangular coordinate system from the unified design bases of the part. To do this, you must select the origin of coordinates and the direction of the axes. It is desirable that the direction of the axes of the relative coordinate system of the part coincide after its installation on the machine with the direction of the coordinate axes of the machine.
When applying dimensions on drawings, in some cases, holes, groups of holes or part elements can be specified in the local coordinate system, as shown for hole B (Fig. 11.8, a). The transition from such a system with the beginning at point A to the main system does not cause difficulties.
Mounting holes located at one or another radius from the center of the main hole are usually set by the central angle of the arc between their axes and radii. For CNC machines, such information should be replaced by the coordinates of the axes of each hole (Fig. 11.8, b). In the example under consideration, it is advisable to assign the axis of the large hole as the origin of coordinates, since it provides a minimum length of idle (positioning) moves during processing.
Rice. 11.8. Dimensioning on the drawings of parts for CNC machines:
a) in the local coordinate system; b) in the coordinate system of the main hole
Parts often have a large number of small mounting holes. Specifying the coordinates of the axis of each of them is impractical, because this makes the drawing difficult to read. In such cases, to indicate the dimensions, it is rational to use the tabular method, which is also convenient for programming (Fig. 11.9, a).
Rice. 11.9. Dimensioning on detail drawings using the tabular method:
a) axes of mounting holes; b) curvilinear contours
According to the general rule for applying dimensions on the drawings of parts machined on lathes, sections with tight tolerances (dimensions a 1, a 2, a 3 in Fig. 11.10, a) and intermediate sections with wide tolerances (dimensions in 1, in 2 , in 3 , in 4). This is quite justified for machines with manual control, because. the worker only needs to maintain exactly these dimensions. For a CNC machine, this does not matter, because the accuracy of the displacements is the same, and the origin, as a rule, does not coincide with the design base and is outside the part. Therefore, dimensions for such parts should be applied in a chain (Fig. 11.10, b).
Rice. 11.10. Dimensioning on drawings of parts for turning:
a) on machines with manual control; b) on CNC machines
In general, the application of dimensions on the drawings of parts processed on CNC machines should be such that when preparing the control program there is no need to recalculate them.
And so, within the framework of this article-instruction, I want you, together with the author of the project, a 21-year-old mechanic and designer, to make your own. The narration will be conducted in the first person, but know that, to my great regret, I am not sharing my experience, but only freely retelling the author of this project.
There will be a lot of drawings in this article, the notes to them are made in English, but I am sure that a real techie will understand everything without further ado. For ease of understanding, I will break the story into "steps".
Foreword from the author
Already at the age of 12, I dreamed of building a machine that would be able to create various things. A machine that will give me the ability to make any household item. Two years later, I came across the phrase CNC or more precisely, to the phrase "CNC milling machine". After I found out that there are people who can make such a machine on their own for their own needs, in their own garage, I realized that I could do it too. I must do it! For three months, I tried to collect the right parts, but did not budge. So my obsession gradually faded away.
In August 2013, the idea of building a CNC milling machine re-engaged me. I had just completed my bachelor's degree from the University of Industrial Design, so I was quite confident in my abilities. Now I clearly understood the difference between me today and me five years ago. I learned how to work with metal, mastered the techniques of working on manual metalworking machines, but most importantly, I learned how to use development tools. I hope this tutorial will inspire you to create your own CNC machine!
Step 1: Design and CAD Model
It all starts with thoughtful design. I made several sketches to get a better feel for the size and shape of the future machine. After that I created a CAD model using SolidWorks. After I modeled all the parts and assemblies of the machine, I prepared technical drawings. I used these drawings for the manufacture of parts on manual metalworking machines: and.
I'll be honest, I like good ones. handy tools. That is why I tried to make sure that the operations on maintenance and adjustment of the machine were made as easy as possible. I placed the bearings in special blocks in order to be able to quickly replace. The guides are serviceable so my car will always be clean when the job is done.
Downloads "Step 1"
dimensions
Step 2: Bed
The bed provides the machine with the necessary rigidity. It will be equipped with a movable portal, stepper motors, Z-axis and spindle, and later the work surface. I used two 40x80mm Maytec aluminum profiles and two 10mm thick aluminum end plates to create the base frame. I connected all the elements to each other on aluminum corners. To strengthen the structure inside the main frame, I made an additional square frame from profiles of a smaller section.
In order to avoid dust on the rails in the future, I installed aluminum protective corners. The angle is mounted using T-nuts, which are installed in one of the grooves of the profile.
Both end plates are fitted with bearing blocks for mounting the drive screw.
Carrier frame assembly
Corners to protect the rails
Downloads "Step 2"
Drawings of the main elements of the bed
Step 3: Portal
The movable portal is the executive body of your machine, it moves along the X axis and carries the milling spindle and the Z axis support. The higher the portal, the thicker the workpiece that you can process. However, a high gantry is less resistant to the loads that occur during processing. The high side posts of the portal act as levers relative to the linear rolling bearings.
The main task that I planned to solve on my CNC milling machine was the processing of aluminum parts. Since the maximum thickness of aluminum blanks suitable for me is 60 mm, I decided to make the portal clearance (the distance from the working surface to the upper cross beam) equal to 125 mm. In SolidWorks, I converted all my measurements into a model and technical drawings. Due to the complexity of the parts, I processed them on an industrial CNC machining center, which additionally allowed me to process chamfers, which would be very difficult to do on a manual metal milling machine.
Downloads "Step 3"
Step 4: Z Axis Caliper
In the Z axis design, I used a front panel that attaches to the Y axis movement bearings, two plates to reinforce the assembly, a plate to mount the stepper motor, and a panel to mount the milling spindle. On the front panel, I installed two profile guides along which the spindle will move along the Z axis. Please note that the Z axis screw does not have a counter support at the bottom.
Downloads "Step 4"
Step 5: Guides
Guides provide the ability to move in all directions, ensure smooth and precise movements. Any play in one of the directions can cause inaccuracies in the processing of your products. I chose the most expensive option - profiled hardened steel rails. This will allow the structure to withstand high loads and provide the positioning accuracy I need. To ensure the guides are parallel, I used a special indicator during their installation. The maximum deviation relative to each other was no more than 0.01 mm.
Step 6: Screws and Pulleys
Screws convert rotational motion from stepper motors into linear motion. When designing your machine, you can choose from several options for this assembly: A screw-nut pair or a ball screw pair (ball screw). The screw nut, as a rule, is subjected to more frictional forces during operation, and is also less accurate relative to the ball screw. If you need increased accuracy, then you definitely need to opt for a ball screw. But you should know that ball screws are quite expensive.
When choosing CNC Router(CNC Router) decide:
1. What material are you going to work with. The requirements for the rigidity of the design of the milling machine and its type depend on this.
For example, a plywood CNC machine will only process wood (including plywood) and plastics (including composite materials - plastic with foil).
On a milling machine made of aluminum, it is already possible to process non-ferrous metal blanks, while the processing speed of wood products will also increase.
Aluminum milling machines are not suitable for steel processing; massive machines with a cast iron bed are already needed here, while the processing of non-ferrous metals on such milling machines will be more efficient.
2. with the size of the workpieces and the size of the working field of the milling machine. This defines the requirements for the mechanics of a CNC machine.
When choosing a machine, pay attention to studying the mechanics of the machine, the capabilities of the machine depend on its choice, and it is impossible to replace it without a significant alteration of the design!
Mechanics CNC milling machine made of plywood and aluminum is often the same. More details below in the text.
But the larger the size of the working field of the machine, the more rigid and expensive linear motion guides will be required for its assembly.
When choosing machines for high-rise workpieces with large height differences, there is a common misconception that it is enough to choose a machine with a large Z-travel. But even with a large Z-travel, it is impossible to produce a part with steep slopes if the height of the part is greater than the working length of the cutter, that is, more than 50 mm.
Consider the device of a milling machine and options for choosing on the example of CNC machines of the Modelist series.
A) Choice of CNC machine design
There are two options for building CNC machines:
1) designs with movable table, picture 1.
2) design with movable portal, figure 2.
Picture 1Sliding Table Milling Machine
Advantages design of the machine with a movable table - this is ease of implementation, greater rigidity of the machine due to the fact that the portal is fixed and fixed to the frame (base) of the machine.
Flaw- large dimensions compared to the design with a movable portal, and the impossibility of processing heavy parts due to the fact that the movable table carries the part. This design is quite suitable for processing wood and plastics, that is, light materials.
figure 2 Milling machine with a movable portal (gantry machine)
Advantages designs of a milling machine with a movable portal:
Rigid table that can withstand the heavy weight of the workpiece,
Unlimited workpiece length,
compactness,
Possibility of execution of the machine without a table (for example, to install a rotary axis).
Flaws:
Less structural rigidity.
The need to use more rigid (and expensive) guides (due to the fact that the portal "hangs" on the guides, and is not fixed to the rigid frame of the machine, as in the design with a moving table).
B) Choice of mechanics of CNC milling machine
The mechanics are presented (see the numbers in Fig. 1, Fig. 2 and Fig. 3):
3 - guide holders
4 - linear bearings or sleeves
5 - support bearings (for fastening lead screws)
6 - lead screws
10 - coupling for connecting the shaft of the lead screw with the shaft of stepper motors (SM)
12 - running nut
figure 3
Selection of the linear movement system of the milling machine (guides - linear bearings, lead screw - lead nut).
As guides can be used:
1) roller guides, Figure 4.5
Figure 4 
Figure 5
This type of guide has found its way into the designs of amateur lasers and machine tools from the furniture industry, Figure 6
The disadvantage is low load capacity and low resource, since they were not originally intended for use in machines with a large number of movements and high loads, low strength aluminum profile guides leads to collapse, Figure 5 and, as a result, an unrecoverable backlash, which makes the further use of the machine unsuitable.
Another version of roller guides, Figure 7, is also not suitable for high loads and therefore is used only in laser machines.
Figure 7
2) round guides, are a steel shaft made of high quality wear-resistant bearing steel with a ground surface, surface hardened and hard chromium plating, shown under the number 2 in figure 2.
This is the optimal solution for amateur designs, because. Cylindrical guides have sufficient rigidity to handle soft materials in small CNC machine sizes at a relatively low cost. Below is a table for selecting the diameter of cylindrical guides, depending on the maximum length and minimum deflection.
Some Chinese manufacturers of cheap machine tools guides of insufficient diameter, which leads to a decrease in accuracy, for example, when used on an aluminum machine at a working length of 400 mm, guides with a diameter of 16 mm will lead to deflection in the center under its own weight by 0.3..0.5 mm (depending on the weight of the portal).
With the right choice of shaft diameter, the design of machines using them is quite strong, the large weight of the shafts gives the structure good stability, overall structural rigidity. On machines larger than a meter, the use of round guides requires a significant increase in diameter to maintain minimum deflection, which makes the use of round guides an unreasonably expensive and heavy solution.
| Axis length | Plywood machine | Aluminum woodworking machine | Aluminum machine for aluminum work | |
| 200mm | 12 | 12 | 16 | 12 |
| 300mm | 16 | 16 | 20 | 16 |
| 400mm | 16 | 20 | 20 | 16 |
| 600mm | 20 | 25 | 30 | 16 |
| 900mm | 25 | 30 | 35 | 16 |
3) profile rail guides
Polished shafts on large machines are being replaced by profile guides. The use of a support along the entire length of the guide allows the use of guides of much smaller diameters. But the use of this type of guide imposes high requirements to the rigidity of the supporting frame of the machine, since the beds made of sheet duralumin or sheet steel are not rigid in themselves. The small diameter of the rail guides requires the use of a thick-walled steel profiled pipe or a large-section structural aluminum profile in the design of the machine to obtain the necessary rigidity and load-bearing capacity of the machine frame.
The use of a special shape of the profile rail allows for better wear resistance compared to other types of rails.
Figure 8
4) Cylindrical guides on a support
Cylindrical guides on a support are a cheaper analogue of profile guides.
As well as profile ones, they require the use of not sheet materials in the frame of the machine, but professional pipes of large cross section.
Advantages - no deflection and no spring effect. The price is twice as high as that of cylindrical guides. Their use is justified when the travel length is above 500mm.
figure 9 Cylindrical guides on a support
The move can be done as bushings(sliding friction) - fig.10 on the left, and using linear bearings(rolling friction)- rice. 10 right.
figure 10 Bushings and linear bearings
The disadvantage of sliding bushings is the wear of the bushings, leading to the appearance of backlash, and an increased effort to overcome sliding friction, requiring the use of more powerful and expensive stepper motors (SM). Their advantage is low price.
Recently, the price of linear bearings has dropped so much that it is economically viable to choose even in inexpensive hobby designs. The advantage of linear bearings is a lower coefficient of friction compared to sleeves, and, accordingly, most of the power of stepper motors goes to useful movements, and not to combat friction, which makes it possible to use motors of lower power.
For conversion rotary motion in translational on the CNC machine, it is necessary to use a screw gear ( lead screw ). Due to the rotation of the screw, the nut moves forward. In milling and engraving machines can be used sliding screw gears and helical rolling gears .
The disadvantage of a sliding screw gear is a rather large friction, which limits its use at high speeds and leads to wear on the nut.
Sliding screw gears:
1) metric screw. The advantage of a metric screw is its low price. Disadvantages - low accuracy, small step and low speed. Max speed propeller displacement (velocity mm`s per min) based on the maximum speed of the stepper motor (600rpm). The best drivers will keep torque up to 900rpm. With this rotation speed, you can get a linear displacement:
For M8 screw (thread pitch 1.25mm) - no more than 750mm/min,
For M10 screw (thread pitch 1.5mm) - 900mm/min,
For M12 screw (thread pitch 1.75mm) - 1050mm/min,
For M14 screw (thread pitch 2.00mm) - 1200mm/min.
At maximum speed, the motor will have about 30-40% of its originally specified torque, and this mode is used exclusively for idle movements.
When working at such a low feed, increased consumption for cutters, after a few hours of work, carbon deposits form on the cutters.
2) keystone screw. In the twentieth century, occupied a leading position in machine tools for metalworking, before the advent of ball screws. Advantage - high accuracy, large thread pitch, and consequently, high speed of movement. It is necessary to pay attention to the type of processing, the smoother and even the surface of the screw, the longer the service life of the screw-nut transmission. Rolled screws have an advantage over threaded screws. Disadvantages of trapezoidal screw-nut transmission - a rather high price compared to a metric screw, sliding friction requires the use of stepper motors of sufficiently high power. The most common screws are TR10x2 (diameter 10mm, thread pitch 2mm), TR12x3 (diameter 12mm, thread pitch 3mm) and TR16x4 (diameter 16mm, thread pitch 4mm). In machine tools, the marking of such a gear TR10x2, TR12x3, TR12x4, TR16x4
Rolling screw drives:
Ball screw transmission (SVP). In the Ball Screw, sliding friction is replaced by rolling friction. To achieve this, in a ball screw, the screw and nut are separated by balls that roll in the recesses of the screw threads. Recirculation of the balls is ensured by means of return channels that run parallel to the axis of the screw.
Figure 12
The ball screw provides the ability to work under heavy loads, good running smoothness, significantly increased resource (durability) due to reduced friction and lubrication, increased efficiency (up to 90%) due to less friction. It is capable of operating at high speeds, provides high positioning accuracy, high rigidity and no backlash. That is, machines using ball screws have a much longer resource, but have a higher price. The machines are marked SFU1605, SFU1610, SFU2005, SFU2010, where SFU is a single nut, DFU is a double nut, the first two digits are the screw diameter, the second two are the thread pitch.
lead screw milling machine can be attached as follows:
1) Design with one support bearing. Fastening is carried out on one side of the screw with a nut to the support bearing. The second side of the screw is attached to the stepper motor shaft through a rigid coupling. Advantages - simplicity of design, disadvantage - increased load on the stepper motor bearing.
2) Design with two thrust bearings. The design uses two support bearings in the inner sides of the portal. The disadvantage of the design is a more complicated implementation compared to option 1). The advantage is less vibration if the screw is not perfectly even.
3) Design with two support bearings in tension. The design uses two support bearings on the outer sides of the portal. Advantages - the screw is not deformed, unlike the second option. The disadvantage is a more complex implementation of the design, compared with the first and second options.
Lead nuts there are:
Bronze backlash-free. The advantage of such nuts is durability. Disadvantages - difficult to manufacture (as a result - high price) and have a high coefficient of friction in comparison with caprolon nuts.
Caprolon backlash-free. Currently, caprolon has become widespread and is increasingly replacing metal in professional designs. A running nut made of graphite-filled caprolon has a significantly lower coefficient of friction compared to the same bronze.
figure 14 Lead nut made of graphite-filled caprolon
In the ball screw nut (ball screw), sliding friction is replaced by rolling friction. Advantages - low friction, the ability to work on high speeds rotation. The disadvantage is the high price.
Coupling selection
1) connection using a rigid coupling. Advantages: rigid couplings transmit more torque from shaft to shaft, no backlash under heavy loads. Disadvantages: requires precise installation, as this coupling does not compensate for misalignment and misalignment of the shafts.
2) connection using a bellows (split) coupling. The advantage of using a bellows coupling is that its use allows you to compensate for misalignment of the installation of the drive shaft and the axis of the stepper motor up to 0.2mm and misalignment up to 2.5 degrees, resulting in less load on the stepper motor bearing and a longer stepper motor resource. It also allows you to dampen the resulting vibrations.
3) connection using a cam clutch. Advantages: allows you to dampen the resulting vibrations, transmit more torque from shaft to shaft, in comparison with a split one. Disadvantages: less misalignment compensation, misalignment of the installation of the drive shaft and the axis of the stepper motor up to 0.1 mm and misalignment up to 1.0 degrees.
C) Choice of electronics
Electronics is presented (see fig. 1 and 2):
7 - stepper motor controller
8 - power supply of the stepper motor controller
11 - stepper motors
There are 4-wire, 6-wire and 8-wire stepper motors . All of them can be used. In most modern controllers, the connection is carried out using a four-wire circuit. The rest of the conductors are not used.
When choosing a machine, it is important that the stepper motor has sufficient power to move the working tool without losing steps, that is, without gaps. The larger the screw thread pitch, the more powerful motors will be required. Usually, the greater the current of the motor, the greater its torque (power).
Many motors have 8 outputs for each half winding separately - this allows you to connect a motor with windings connected in series or in parallel. With windings connected in parallel, you will need a driver with twice the current as with series-connected windings, but half the voltage will be enough.
With series, on the contrary - to achieve the rated torque, half the current will be required, but to achieve maximum speed, twice the voltage will be required.
The amount of movement per step is typically 1.8 degrees.
For 1.8, you get 200 steps per full turn. Accordingly, to calculate the number of steps per mm ( "Steps per mm" (Step per mm)) we use the formula: number of steps per revolution / screw pitch. For a screw with a pitch of 2mm, we get: 200/2=100 pitches/mm.
Controller selection
1) DSP controllers. Advantages - the ability to select ports (LPT, USB, Ethernet) and the independence of the frequencies of STEP and DIR signals from work operating system. Disadvantages - high price (from 10,000 rubles).
2) Controllers from Chinese manufacturers for amateur machine tools. Advantages - low price (from 2500 rubles). The disadvantage is the increased requirements for the stability of the operating system, it requires compliance with certain configuration rules, it is preferable to use a dedicated computer, only LPT versions are available.
3) Amateur designs of controllers on discrete elements. Low price Chinese controllers are replacing amateur designs.
The most widespread in amateur machine designs are Chinese controllers.
Selecting a power supply
Nema17 motors require at least 150W power supply
Nema23 motors require at least 200W power supply
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