How I Designed Circuit Board to Run my home made CNC router

[X2YeZ CAM CNC]

Below I will try to highlight some of the features I incorporated into the design of my first and second cnc machine. I called it the "X2YeZ CAM CNC" machine. Completely constructed from off the shelf parts I bought at HomeDepot. Motors were spare parts I had laying around. The frame is made of aluminum. It has a vacuum table which runs off a shopvac. The controller I designed has memory and a serial interface to my PC. I create my layouts in CorelDraw, export them to disk and then import into SignLab. I wrote a driver for SignLab to use for output file creation. I open the software interface I wrote for the CNC machine and open the file plotted by SignLab. The interface gives me the details of the movements the machine will take. I can adjust offsets, view routes in 2D or 3D (color) then send the whole file to the router machine and free up PC for other work. The cnc router will indicate the position and time remaining for the cutting as the machine moves around the work. The interface network will allow more than one machine to be operated from one PC. I have posted video on youtube of the machine and various signs and sign letters I have made on my machine. Longest job I ever sent to it took 7 hours and 45 mins and it made ever move correctly. I am not a machinist ... but I am an electronics engineer with lots of spare time and just happen to work part time for a sign maker.

[Al_The_Man]

On a side note, what version of Corel are you using? I am thinking of upgrading but I would like something for 3d layouts, the older version I have is not too friendly for this.
I am looking at 4X?
Al.

[X2YeZ CAM CNC]

Using version 10 I believe

[X2YeZ CAM CNC]

After I drew up a schematic I created my board layout with Corel Draw.
Got the artwork printed at a local color copy shop.
Came home and shot a printed circuit board using a pre-sensitized copper clad pc board.
Etched and thin plated the circuit board and then sat down and drilled all the holes.
Installed the components and hooked the board up to my Microchip ICD module and started programming the 16F877 microcontroller.

I needed a PC interface so I created a simple one in Visual Basic...works through serial port...more later

Here are a few pictures for everyone to enjoy.

[X2YeZ CAM CNC]

Used unipolar stepper motors converted to bi-polar.
My driver is 2 phase with 4 level current limited chopper pwm type to keep the motors cool.
The micro controller is programmed to switch to a holding current after the motor motion times out.
The original board has the ability to play musical notes so it plays a little tune when booting & finished cutting.
The LCD display is a two line show X,Y & Z positions and what move it is working on as well as how much time is left until finished.
The keypad has 8 keys for manual control and self-diagnostics.
E-stop button on front panel as well as on PC.
Each axis drive has and photo sensor to detect home and end of all 4 rails.
The X axis is drive by two independent stepper motors.
I used 1/4-20 threaded rod for lead screws.
1.8 degree motors give 4000 steps per inch with no micro stepping.
The PC software send the 3D moves (X,Y,Z=tool depth) to controller as one large file. If the whole thing is received the controller automatically turn on the power for my vacuum table and the router.
My first build used a Dremmel but could not stand the thing. So I used a Rigid Variable Speed Laminate cutter on my second build.
Takes a wide variety of 1/4 inch router bits. More to come.

[X2YeZ CAM CNC]

First thing I had the machine do was drill out my vacuum table.
I used the Dremmel again just for the small bit.

The last photo is the first sign carved with the Rigid router attachment.
Enjoy the photos.

[X2YeZ CAM CNC]

The PC Software interface is fairly simple.
I can load a file and the program will check size and limit offset controls.
I click on send and the vector data goes to the controller thru serial port.

The photos show the various screens in the software interface.
Diagnostic screen can look into memory for cpu or ram moves are stored in.

Forgot to mention the plug in I2C memory module for PCless operation from a memory storage device plugged into the machine. Cool eh!

[X2YeZ CAM CNC]

Here a whole lot of photos of my newest version of the controller without sound.

Shooting the artwork onto PC board
Etching the printed circuit board

[X2YeZ CAM CNC]

6 inch by 6 inch printed circuit board
holes all drilled and most of the parts installed

[X2YeZ CAM CNC]

Close up of components on controller board.

[X2YeZ CAM CNC]

Close up of the back of the printed circuit boards with surface mounted components.

[X2YeZ CAM CNC]

Some samples of things I have made using my home engineered CNC router machine. Enjoy eh!