Below my project homade cnc milling machine. Machine was built with used components (eg old furniture tops, which were from renovated kitchen) and cheap Chinese components. The design of milling machine evolved during construction. After the first tests of machining are made minor amendments. Machine design has never been well modeled or drawn. The whole concept developed during the construction. With such a simple design is a shortened construction time. This is not a commercial project. At the moment, I am already working on the next version of the machine, which will be more compact and controlled from arduino uno.
The aim of the project was to create a machine that can be helpful for simple construction works. It turned out, however, that work on the machine gives a lot of fun and honestly I would recommend anyone to build own cnc machine. Because of that the internet is a lot of projects CNC machines, I will focus primarily on the most important problems that can occur when making their own machines and machining demonstration of my machine.
Step 1: Concept
The aim of the project is to build a CNC milling machine, which will be able to effectively treat soft materials like wood, plastic, aluminium. By building such a machine you need to be aware that it can not match the commercial machines whose value starts at $ 100,000. In my case, I decided to control Mach3. The advantage of this control is the low price at very high capacity. The only limitation here is that a computer, must be equipped with an outdated operating system (Windows XP). In my case, I used an old laptop that had a parallel connector LPT. The heart of the machine is cheap 3-axis controller-based on TB6560 and 3 stepper noname motors (X axis - 3A 3Nm, Y-axis - 2 Nm 2,8A, Z axis - 2,8A 2 Nm). To power the system has been used in switching power supply 24V 12A. Spindle 12 000 rpm 48V 300W initially was to be powered by a 24V power supply. Ultimately the power supply was joined in series with laptop power supply 19V 4A. In this way, the spindle got 43V supply and it is possible to achive 10 000 rpm.
The mechanical design is based on the cross table (XY). The Z axis is mounted on frame of furniture boards. Enough material turned out to use relatively thick guides. The X-axis rails are used roller guide diameter 20 (table is supported on 4 linear slide block) in the Y-axis in the first version I used the guide roller diameter 10. As it turned out later, I replaced it to supported guide roller diameter 16. The rigidity of the structure here has a very large impact on the functionality of the machine and its machining capabilities. In the Z-axis I used guides diameter 20 but the spindle column moving only on 2 slide block. It quickly became clear that it was necessary to add 2 slide block to ensure greater rigidity of machine. To feed in the X-axis is used ball screw Rexroth diameter 32. The Y and Z axes used the trapezoidal screws diameter 10. The use of a professional screw axis X stemmed from the fact that it owned one on stock. Certainly I'm not mount this screw if I had to buy it in the store.
Step 2: Installation
Mechanical installation started from the X-axis guide rollers are supported on standard supports SK20 and furniture board. This simplifies construct machines and the cost of aluminum brackets is also small. However note a attention to the whole table was moving smoothly in the entire range. After installation guides, we can proceed to install the screws. Take note that the set screw as parallel as possible to the guide in the axis. After assembling the X-axis, we can proceed to install the Y-axis table principle is similar. In the first place it is important to set the perpendicularity of the Y-axis guide to X. Z axis is mounted independently. In this case, it is necessary to set squareness XZ and YZ.
Then we can mount stepper motors and spindle.
Electrical installation is the case of the driver TB6560 trivial. I recommend to read instructions of the controller and enjoy the experience of the people who mount the machine with the same driver. It is important here not to get attached to one solution only to choose the most beneficial for themselves.
All geometry settings in this type of construction can be corrected later. It is, however, to do the best as you can.
Step 3: Set Up!
Starting the machine is based on the configuration of the environment MACH3. You have to remember to specify the pitch of the propeller control and properly tune the motors. Launching best be divided into steps. In my case, I started from the X axis. I must find the maximum speed at which the motors do not lose steps. It is important that during the movement, there were no vibrations. In my machine I did not mount the limit switches. This is a relatively dangerous. In such machine should be remembered that the stepper motors in spite of the small size have relatively large torques.
In the event that we will go outside of range it can cause damage to the machine not to mention the possibility of crushing a finger or a hand. I recommend extreme caution especially in the commissioning phase.
Step 4: Presentation
Here are the photos and videos that I was able to shoot during the construction and processing.
I hope you anjoy watching my videos.