Homemade cnc milling machine from a steel profile. Homemade CNC milling machine: do-it-yourself assembly

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, notes to them are made on English language, but I am sure that a real techie will understand everything without extra words. 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.

To be honest, I love good 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.

The question of how to make a CNC machine can be answered briefly. Knowing that a home-made CNC milling machine, in general, is a complex device with a complex structure, it is desirable for the designer:

• get drawings;
• purchase reliable components and fasteners;
• prepare a good tool;
• have a CNC lathe and drill on hand to quickly produce.

It does not hurt to watch the video - a kind of instruction, teaching - where to start. And I’ll start with preparation, I’ll buy everything I need, I’ll deal with the drawing - here the right decision budding designer. So preparatory stage, preceding the assembly, is very important.

Works of the preparatory stage

To make a homemade CNC for milling, there are two options:

1. You take a ready-made running set of parts (specially selected units), from which we assemble the equipment ourselves.
2. Find (make) all the components and start assembling the CNC machine with your own hands, which would meet all the requirements.

It is important to decide on the purpose, size and design (how to do without a drawing of a home-made CNC machine), find schemes for its manufacture, purchase or manufacture some of the parts that are needed for this, acquire lead screws.

If a decision is made to create a CNC machine with your own hands and do without ready-made sets of components and mechanisms, fasteners, you need the scheme assembled according to which the machine will work.

Usually, having found a schematic diagram of the device, they first model all the details of the machine, prepare technical drawings, and then use them on turning and milling machines (sometimes you need to use a drilling machine) to make components from plywood or aluminum. Most often, work surfaces (also called a desktop) are plywood with a thickness of 18 mm.

Assembly of some important machine components

In the machine that you started to assemble with your own hands, it is necessary to provide for a number of critical nodes that ensure the vertical movement of the working tool. In this list:

• screw transmission - rotation is transmitted using a toothed belt. It is good because it does not slip on the pulleys, evenly transferring forces to the shaft milling equipment;
• if a stepper motor (SM) is used for a mini-machine, it is advisable to take a carriage from a larger printer model - more powerful; old dot matrix printers had fairly powerful electric motors;

• for a three-coordinate device, you need three step motors. Well, if there are 5 control wires in each, the functionality of the mini-machine will increase. It is worth evaluating the magnitude of the parameters: supply voltage, winding resistance and the rotation angle of the stepper motor in one step. To connect each stepper motor, a separate controller is needed;
• with the help of screws, the rotational movement from the stepper motor is converted into a linear one. To achieve high accuracy, many consider it necessary to have ball screws (ball screws), but this component is not cheap. When choosing a set of nuts and mounting screws for mounting blocks, they are chosen with plastic inserts, this reduces friction and eliminates backlash;

• instead of a stepper motor, you can take a conventional electric motor, after a little refinement;
• the vertical axis that moves the tool in 3D, covering the entire XY table. It is made from aluminum plate. It is important that the dimensions of the axis are adjusted to the dimensions of the device. In the presence of a muffle furnace, the axis can be cast according to the dimensions of the drawings.

Below is a drawing made in three projections: side, rear, and top view.

Maximum attention - bed

The necessary rigidity to the machine is provided by the frame. A movable portal, a system of rail guides, a stepper motor, a work surface, a Z axis and a spindle are installed on it.

For example, one of the creators of a self-made CNC machine made the supporting frame from the Maytec aluminum profile - two parts (section 40x80 mm) and two end plates 10 mm thick from the same material, connecting the elements with aluminum corners. The design is reinforced, inside the frame a frame is made of smaller profiles in the shape of a square.

The bed is mounted without the use of welded joints (welds are poorly able to withstand vibration loads). It is better to use T-nuts as fasteners. On the end plates, a bearing block is provided for installing the lead screw. You will need a plain bearing and a spindle bearing.

The craftsman determined the main task of the hand-made CNC machine to be the manufacture of aluminum parts. Since workpieces with a maximum thickness of 60 mm were suitable for him, he made a portal clearance of 125 mm (this is the distance from the upper transverse beam to the working surface).

This difficult installation process

Collect homemade cnc machines, after preparing the components, it is better strictly according to the drawing so that they work. The assembly process, using lead screws, should be performed in the following sequence:

• a knowledgeable craftsman begins by attaching the first two step motors to the body - behind the vertical axis of the equipment. One is responsible for the horizontal movement of the milling head (rail guides), and the second for movement in the vertical plane;
• a movable gantry moving along the x-axis carries the milling spindle and carriage (z-axis). The higher the portal, the larger the workpiece can be processed. But at a high portal, in the process of processing, resistance to emerging loads decreases;

• front, rear, top, middle and bottom plates are used to fasten Z-axis stepper motors, linear guides. In the same place, make a lodgement for the milling spindle;
• the drive is assembled from carefully selected nuts and studs. To fix the motor shaft and attach it to the stud, use the rubber winding of a thick electric cable. Screws inserted into the nylon sleeve can be used as a retainer.

Then the assembly of the remaining components and assemblies of the homemade begins.

We mount the electronic filling of the machine

To make a CNC machine with your own hands and control it, you need to operate with a properly selected numerical control, high-quality printed circuit boards and electronic components (especially if they are Chinese), which will allow you to implement all the functionality on a CNC machine, processing a part of a complex configuration.

In order to avoid problems in management, home-made CNC machines, among the nodes, have the following mandatory:

• stepper motors, some stopped like Nema;
• LPT port through which the CNC control unit can be connected to the machine;
• drivers for controllers, they are installed on a mini-milling machine, connected in accordance with the diagram;

• switching boards (controllers);
• a 36V power supply unit with a step-down transformer that converts to 5V to power the control circuit;
• laptop or PC;
• emergency stop button.

Only after that, the CNC machines are tested (at the same time, the craftsman will make a test run by downloading all the programs), the existing shortcomings are identified and eliminated.

Instead of a conclusion

As you can see, making a CNC that is not inferior to Chinese models is real. Having made a set of spare parts with the right size, having high-quality bearings and enough fasteners for assembly, this task is within the power of those who are interested in software engineering. It won't take long to find an example.

In the photo below - some examples of machines with numerical control, which are made by the same craftsmen, not professionals. Not a single part was made hastily, of arbitrary size, but fitting to the block with great accuracy, with careful alignment of the axes, using high-quality lead screws and with reliable bearings. The statement is true: as you collect, so you will work.

On the CNC, processing of an duralumin blank is performed. Such a machine, which was assembled by a craftsman, can perform a lot of milling work.

There are a lot of similar stories on the net, and I probably won’t surprise anyone, but maybe this article will be useful to someone. This story began at the end of 2016, when my friend, a partner in the development and production of test equipment, and I accumulated a certain amount of money. In order not to just waste money (the business is young), they decided to invest in the business, after which the idea of ​​\u200b\u200bmanufacturing a CNC machine came to mind. I already had experience in building and working with this kind of equipment, and the main area of ​​​​our activity is design and metalworking, which accompanied the idea of ​​​​building a CNC machine.

That's when the movement began, which continues to this day ...

Everything continued from the study of forums dedicated to CNC topics and the choice of the basic concept of the machine design. Having previously decided on the materials to be processed on the future machine and its working field, the first paper sketches appeared, which were subsequently transferred to a computer. In the environment of three-dimensional modeling KOMPAS 3D, the machine was visualized and began to acquire smaller details and nuances, which turned out to be more than we would like, some of which we solve to this day.

One of the initial decisions was to determine the materials processed on the machine and the dimensions of the working field of the machine. As for the materials, the solution was quite simple - it was wood, plastic, composite materials and non-ferrous metals (mainly duralumin). Since we mainly have metalworking machines in our production, sometimes a machine is required that would quickly process materials that are quite easy to process along a curved path, and this would subsequently reduce the cost of production of ordered parts. Starting from the selected materials, mainly supplied in sheet packaging, with standard sizes 2.44x1.22 meters (GOST 30427-96 for plywood). Rounding these dimensions came to the following values: 2.5x1.5 meters, working space definitely, with the exception of the height of the tool, this value was chosen for reasons of the possibility of installing a vice and assumed that we would not have workpieces thicker than 200mm. We also took into account the moment, if it is necessary to process the end face of any sheet part longer than 200 mm, for this the tool travels beyond the dimensions of the machine base, and the part / workpiece itself is attached to the end side of the base, thereby processing the end face of the part can take place.

Machine design is a prefabricated frame base from the 80th profile pipe with a wall of 4 mm. On both sides of the length of the base, profile rolling guides of the 25th standard size are fixed, on which a portal is installed, made in the form of three welded together profile pipes the same size as the base.

The machine is four axial and each axis is driven by a ball screw. Two axes are located in parallel along the long side of the machine, paired by software and tied to the X coordinate. Accordingly, the remaining two axes are the Y and Z coordinates.

Why we settled on a prefabricated frame: initially they wanted to make a purely welded structure with embedded welded sheets for milling, installation of guides and ballscrew supports, but they did not find a sufficiently large milling-coordinate machine for milling. I had to draw a prefabricated frame so that I could process all the details on my own with the metalworking machines available in the production. Each part that was exposed to electric arc welding was annealed to relieve internal stresses. Further, all mating surfaces were milled, and later the fitting had to be scraped in places.

Getting ahead, I want to say right away that the assembly and manufacture of the frame turned out to be the most time-consuming and financially costly event in the construction of the machine. The original idea with a one-piece welded frame bypasses the prefabricated structure in all respects, in our opinion. Although many may disagree with me.

I want to make a reservation right away that we will not consider machine tools made of aluminum structural profiles here for now, this is rather a matter for another article.

Continuing the assembly of the machine and discussing it on the forums, many began to advise making diagonal steel struts inside the frame and outside to add even more rigidity. We did not neglect this advice, but adding jibs to the design is the same, since the frame turned out to be quite massive (about 400 kg). And upon completion of the project, the perimeter will be covered with sheet steel, which will additionally connect the structure.

Let's now move on to the mechanical issue of this project. As mentioned earlier, the movement of the machine axes was carried out through a ball screw pair with a diameter of 25 mm and a pitch of 10 mm, the rotation of which is transmitted from stepper motors with 86 and 57 flanges. Initially, it was supposed to rotate the propeller itself in order to get rid of unnecessary backlash and additional gears, but they could not have done without them in view of the fact that with a direct connection between the engine and the propeller, the latter would begin to unwind at high speeds, especially when the portal is in extreme positions. Given the fact that the length of the screws along the X axis was almost three meters, and for less sagging, a screw with a diameter of 25 mm was laid, otherwise a 16 mm screw would have been enough.

This nuance was already discovered during the production of parts, and it was necessary to quickly solve this problem by manufacturing a rotating nut, not a screw, which added an additional bearing assembly and belt drive to the design. This solution also made it possible to tighten the screw well between the supports.

The design of the rotating nut is quite simple. Initially, we selected two tapered ball bearings that are mirrored on the ball screw nut, after cutting the thread from its end, to fix the bearing cage on the nut. The bearings, together with the nut, fit into the housing, in turn, the entire structure is mounted on the end of the portal rack. In front of the ball screw, the nuts fastened the adapter sleeve to the screws, which was later turned on the mandrel in assembled form to give alignment. They put a pulley on it and tightened it with two lock nuts.

Obviously, some of you will be wondering - "Why not use a gear rack as a mechanism for transmitting movement?". The answer is quite simple: the ball screw will provide positioning accuracy, greater driving force, and, accordingly, less torque on the motor shaft (this is what I immediately remembered). But there are also disadvantages - a lower speed of movement and, if you take screws of normal quality, then the price, respectively.
By the way, we took TBI ball screws and nuts, enough a budget option, but the quality is appropriate, since out of the 9 meters of the screw taken, 3 meters had to be thrown out, due to the discrepancy in geometric dimensions, none of the nuts simply screwed on ...

As sliding guides, profile rail guides of 25 mm size, manufactured by HIWIN, were used. Mounting grooves were milled for their installation to maintain parallelism between the guides.

They decided to make the ball screw supports on their own, they turned out to be of two types: supports for rotating screws (Y and Z axes) and supports for non-rotating screws (X axis). Supports for rotating screws could be bought, since there were few savings due to in-house production of 4 parts. Another thing is with supports for non-rotating screws - you can’t find such supports for sale.

From what was said earlier, the X-axis is driven by rotating nuts and through a belt gear. It was also decided to make two other axes Y and Z through a belt gear, this will add more mobility in changing the transmitted torque, add aesthetics in view of installing the engine not along the axis of the ball screw screw, but to the side of it, without increasing the dimensions of the machine.

Now let's move smoothly to electrical part, and we will start with the drives, stepper motors were chosen as them, of course, for reasons of lower price compared to motors with feedback. Two engines with an 86th flange were put on the X axis, on the Y and Z axes along an engine with a 56th flange, only with different maximum torque. I will try to present below. full list purchased items...

The electrical circuit of the machine is quite simple, stepper motors are connected to drivers, which, in turn, are connected to an interface board, which is also connected via a parallel LPT port to a personal computer. Drivers used 4 pieces, respectively, one piece for each of the engines. I installed all the drivers the same, to simplify installation and connection, with a maximum current of 4A and a voltage of 50V. As an interface board for CNC machines, I used a relatively budget option, from a domestic manufacturer, as indicated on the website the best way. But I will not confirm or deny this, the board is simple in its application and, most importantly, it works. In my past projects, I used boards from Chinese manufacturers, they also work, and in terms of their periphery they differ little from the one I used in this project. I noticed in all these boards, one may not be significant, but a minus, you can only install up to 3 limit switches on them, but at least two such switches are required for each axis. Or I just didn't get it? If we have a 3-axis machine, then accordingly we need to set the limit switches in the zero coordinates of the machine (this is also called the “home position”) and in the most extreme coordinates so that in the event of a failure or lack of a working field, one or another axis simply does not out of order (simply not broken). In my scheme, I used: 3 limit sensors without contact inductive sensors and an emergency button "E-STOP" in the form of a fungus. The power section is powered by two 48V switching power supplies. and 8A. 2.2 kW water-cooled spindle, respectively connected through a frequency converter. Turnovers are set from a personal computer, since the frequency converter is connected via an interface board. Turnovers are regulated by changing the voltage (0-10 volts) at the corresponding output of the frequency converter.

All electrical components, except for motors, spindle and limit switches, were mounted in an electrical metal cabinet. All control of the machine is carried out from a personal computer, they found an old PC on an ATX form factor motherboard. It would be better to shrink a little and buy a small mini-ITX with an integrated processor and video card. With not small dimensions of the electrical box, all the components were hardly placed inside, they had to be placed close enough to each other. At the bottom of the box, I placed three forced cooling fans, since the air inside the box was very hot. A metal plate was screwed on the front side, with holes for the power buttons and emergency stop buttons. Also, on this overlay, a socket was placed to turn on the PC, I removed it from the case of an old mini computer, it’s a pity that it turned out to be not working. An overlay was also fixed from the back end of the box, holes were placed in it for connectors for connecting 220V power, stepper motors, a spindle and a VGA connector.

All the wires from the engines, the spindle, as well as the water hoses for its cooling, were laid in caterpillar-type flexible cable channels 50 mm wide.

As for the software, Windows XP was installed on a PC placed in an electric box, and one of the most common Mach3 programs was used to control the machine. The program is configured in accordance with the documentation for the interface board, everything is described there quite clearly and in pictures. Why exactly Mach3, but all the same, there was work experience, I heard about other programs, but did not consider them.

Specifications:

Working space, mm: 2700x1670x200;
Axes movement speed, mm/min: 3000;
Spindle power, kW: 2.2;
Dimensions, mm: 2800x2070x1570;
Weight, kg: 1430.

Parts list:

Profile pipe 80x80 mm.
Metal strip 10x80mm.
Ball screw TBI 2510, 9 meters.
Ball screw nuts TBI 2510, 4 pcs.
Profile guides HIWIN carriage HGH25-CA, 12 pcs.
Rail HGH25, 10 meters.
Stepper motors:
NEMA34-8801: 3 pcs.
NEMA 23_2430: 1pc.
Pulley BLA-25-5M-15-A-N14: 4 pcs.
Pulley BLA-40-T5-20-A-N 19: 2 pcs.
Pulley BLA-30-T5-20-A-N14: 2 pcs.

StepMaster v2.5 interface board: 1 pc.
DM542 stepper motor driver: 4pcs (China)
Switching power supply 48V, 8A: 2 pcs. (China)
Frequency converter for 2.2 kW. (China)
Spindle 2.2 kW. (China)

I seem to have listed the main details and components, if something is not included, then write in the comments, I will add it.

Machine experience: In the end, after almost a year and a half, we still launched the machine. First, we set up the positioning accuracy of the axes and their maximum speed. According to more experienced colleagues, the maximum speed of 3 m / min is not high and should be three times higher (for processing wood, plywood, etc.). At the speed that we have reached, the portal and other axes, resting on them with your hands (with your whole body), can hardly be stopped - rushing like a tank. We started testing with the processing of plywood, the cutter goes like clockwork, there is no machine vibration, but they also deepened by a maximum of 10mm in one pass. Although after going deep they began to shallower depths.

After playing with wood and plastic, we decided to gnaw on duralumin, here I was delighted, although I first broke several milling cutters with a diameter of 2 mm, while I was choosing cutting modes. Dural cuts very confidently, and a fairly clean cut is obtained, along the machined edge.

We haven’t tried to process steel yet, but I think that at least the machine will pull engraving, and for milling the spindle is rather weak, it’s a pity to kill it.

And the rest of the machine perfectly copes with the tasks assigned to it.

Conclusion, opinion on the work done: The work done is not small, as a result, we are pretty tired, since no one has canceled the main work. Yes, and a lot of money invested, I won’t say the exact amount, but it’s about 400t.r. In addition to the cost of assembly, the bulk of the costs and most of the forces went to the manufacture of the base. Wow, how we messed with him. And the rest, everything was done as funds, time and finished parts came in to continue the assembly.

The machine turned out to be quite efficient, quite rigid, massive and of high quality. Maintaining good positioning accuracy. When measuring a square made of duralumin, 40x40 in size, the accuracy turned out to be + - 0.05 mm. The processing accuracy of larger parts was not measured.

What's next…: There is still enough work on the machine, in the form of closing the guides and ball screws with dust protection, sheathing the machine around the perimeter and installing ceilings in the middle of the base, which will form 4 large shelves, under the spindle cooling volume, tool storage and equipment. They wanted to equip one of the quarters of the base with a fourth axle. It is also required to install a cyclone on the spindle to remove and collect chips from dust, especially if wood or textolite is processed, dust flies everywhere and settles everywhere.

As for the further fate of the machine, everything is not clear here, since I had a territorial issue (I moved to another city), and now there is almost no one to deal with the machine. And the above plans are not the fact that they will come true. No one could have imagined this two years ago. Add tags

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 it detailed drawing, but also the set necessary tools and related accessories.

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 expenses. 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 of 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 with your own hands that fully meets all your requirements.

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 negative is the instruction in English, but it is quite possible to understand the detailed drawings even 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 only workpieces made of plastic, wood and thin sheet metal can be processed on such a CNC machine. This is explained by the fact that the carriages from the old printer, which will ensure the movement of the 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 gear, and the functionality and characteristics of home-made equipment will not become 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 needs 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 during its installation, and all elements must be connected 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 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 homemade device can be made from 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 to assembled machine system 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 milling machine with your own hands, you will need three stepper motor. 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 will be a big plus if the engines 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 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 of the technological operations that will be performed on it will depend on this. 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 trial run of the machine follows, checking the correct operation of the machine under the control of downloaded programs, identifying shortcomings and promptly eliminating them.