What is a CNC machine? This is a cool thing, which can be used to make other very cool things!
CNC router can cut (eg, plastic or wood) different parts which can then be composed to something (eg a robot or a holder for a beer).
The Internet is full of different instructions on how to make beautiful / reliable / cheap / big / small homemade DIY CNC router.
But I’ve never found how to make a reliable, inexpensive and beautiful CNC controller. Actually, it's called CNC system, but often it is called a CNC controller.
CNC controller - is the brain of the machine. It consists of various electronic circuit boards, computer and a computer program that controls the movement of the machine’s motors, calculate speed and other. Sometimes CNC controllers do without the use of a computer, but I think it greatly limits the possibility of extending the functions of the machine. Suddenly tomorrow you’ll want to install on the machine an additional axis and make more complex parts? Without a computer, and update the program it is much more difficult to do it.
There are many programs that can operate the machine (MACH 3, linux CNC, KCam, CNC-D etc), But I chose MACH 3 CNC since it is very well known, has a large number of users and is easy to install.
And now the fun!
Almost all use usual computers with the installed program. Then make a separate housing for the electronics, drivers, power supply units, etc. It takes a lot of time and space.
I am engaged in the modernization of CNC machines more than 15 years and I know that all must be well protected and shielded in an industrial environment. Long cable caught electrical impulses and disrupt the work of the CNC.
I have machine with 3 coordinates (XYZ), but it has two motors on Y axis (one on each side of the portal).
If you also want to have a convenient and reliable MACH 3 CNC system, follow these instructions:
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Step 1: Select Motors
Specify the type of machine to which you will connect the CNC system. It depends on how much drivers for motors you will need to order. For milling and engraving machines you need 3-4 drivers. For lathes you need 2 driver. Discover the current of your motors. Typically, the current is written on the motor (eg 3.0A)
Step 2: Limit Switches
Decide whether you limit switches and switches of the referent points are needed. I don’t, but it is safer and more comfortable with them because it is not necessary every time accurately set a mill to the start point of the details. Keep in mind that MACH 3 CNC can work with different boards of the optical isolation. The simplest and cheapest (which I have) is to operate the machine via LPT port. But on this board may not have enough free signals to connect all limit switches, emergency buttons, etc. Other boards for the optical isolation, more expensive, but have more signals. For me it is enough PCB for LPT port.
Step 3: Computer Selection
The modular industrial PC consists of individual components. I bought a monitor, a keyboard, a Base module, a drivers, power supply unit and the board of optical isolation. You can connect an ordinary monitor, but this one is protected by glass and ABS plastic, has a computer “power on” button and emergency button.
Step 4: Keyboard Selection
Decide which type of the keyboard you will use. You can use the usual, but the modular PC keyboard - this is a special unit adapted for use on CNC machines. The fact that it is not very comfortable to use standard QWERTY layout of buttons on the machines. The GMSTF buttons and others are often used. Therefore, machine’s keyboard buttons have a different grouping. In this keyboard buttons are arranged with the SIEMENS industrial machines standard. And most important distinction form the usual keyboards - it's 2 rotary encoders. When you work on the machine, it is often necessary to quickly change the speed of the milling tool or spindle speed. It is very inconvenient to press the button to do it many times. Rotary controls for feed and spindle speed adjustment are present in all industrial machines. This keyboard also has such regulators. Very comfortably!
Step 5: Main Block Selection
The system unit includes a housing in which all the modules are inserted. Mandatory - module workstation. This 1.8GHz 1GB RAM, 4 GB HDD embedded computer. By the way, HDD made by FLASH technology and is not afraid of vibration. This is very important in a industrial environment. The remaining blocks are available on request. I ordered all at once because it is very comfortable to have all located in one place, no extra cables, connectors, etc. There is another feature, the cable length from the LPT port to board of the optical isolation should be minimal, since this cable carries signals up to 100 kHz. If a long cable, it is influenced by noise and the machine will lose the coordinates (skip steps). If everything is in one package, the cable length is only 10cm.
Step 6: CNC Software
Now the software. If you choose to use MACH 3 CNC, there are several options. I had a licensed copy of the WINDOWS. You can order WINDOWS installation from the manufacturer, or do it yourself. MACH 3 software costs about 200USD. It can also be ordered at once, or you can use the DEMO version. It is fully operational, but has a limit of 1000 lines of code.
Step 7: Final Stage
And the last stage. The kit comes with a modular computer and with the file of settings for the program MACH 3. This means that the whole set (monitor, keyboard, driver, etc.) will work without additional configuration. You will only need to connect the CNC to the machine according to the schemes, set up the movement speed and direction of movement.
That’s all folks!