CNC

FPGA Card + H Bridge with motors

Developing the electronics and software for a CNC machine with DC servo motors

The embedded systems, are highly integrated systems.
They usually are fisically very small and with a very reduced consume of energy.
With the entrance in the market of the FPGA's. the embedded systems can be reduced even more, and we can talk about SoC (system on chip).
In other words, all the integrant parts of a computer system as the processor, the memory, and the peripherals, fit in a single chip.
FPGA's are blank chips,they can be programmed and develop the electronic circuit we desire. These circuits can be described with special languajes as VHDL and Verilog.

The system that I'm going to talk in this articles, consists in a card with a FPGA Spartan3 and memory.
Its goal will be the control of a CNC machine with 3 DC motors, and it will be comprised of a microprocessed system that will control 3 PWM's outputs, 3 optical encoders inputs and other purpose auxiliary inputs and outputs, to support the final race sensors, buttons, etc...

Milling machine with motors installed

Upgrading a mill to be automatic

The next project that we are going to make is retrofitting a milling machine.
Retrofitting means replacing all the manual elements in the machine for automatic ones. These consist of electric motors, electronic sensors, etc...
A milling machine that is controlled by a computer becomes a CNC device (Computer Numerically Controlled).
In this article we are introducing to the mechanical system of these devices.

Through some years of experience machining with a CNC device, i have seen how easily we can make incredible pieces in metal or more materials in little time, and how the difficulty of machining has moved from the machine itself to the computer programs that designs the pieces. These are the CAD-CAM programs.

A CNC device is for me, one of the most important machines we can have in the yard, and I think it's a must for the professional and the hobbyst.
With a CNC, we can machine all the pieces we need for the projects, fast and with sufficient quality.
With a non automated milling machine, some people are able to make complex things, but with much more work, phisical and mental, and the results usually are not on par with the CNC made pieces.
Also there are shops that can machine the pieces for you, but in the long term it's very expensive for our not deep pockets. There is also the time line, having a cnc in your bag makes you very fast and responsive.
So, I think it's clear that it's cool to have your own cnc machine!!
Our goal is to make a professional machine, this means that there will be no backlash, and it will be fast and reliable (this means we are going to develop a servo motor system with optical encoders).
To understand these terms go on reading...