A simple CNC system!
CNC stands for Computer Numeric Control. A fancy way of saying the computer controls the movements of the machine. Lets look at it this way. Your printer is a CNC machine! When it moves Left to Right it is moving it's X axis. When the paper feeds that's your Y axis. The Z axis is the printhead or inkjet. A CNC milling machine cuts a block of material rather than print on it. The CNC machine can move in three directions at once. This gives it the ability to do 3D signs and shapes. Your printer is only 2D. A printer gets commands from the computer through the parallel port. There is a controller in the printer that takes the commands and turns them into motion. Printer commands are not CNC but the effect is basically the same. Some robotic systems also work this way.
A Simple CNC machine is hooked to the computer VIA the parallel port using a printer cable or a parallel cable. (depends on controller) Please note: I said Simple CNC machines. There are CNC systems out there that use the serial port or a card that fits into the computer. Ok, we have a parallel cable running out of the computer. This gets hooked up to a Controller that drives the motors. Simple controllers have a connector right on them that the parallel cable gets hooked to. The controller gets it's power from an old computer supply or one you build. There are two signals per motors. A Step and a Direction. For each Step sent to the controller the motor turns 1.8 degrees. (With controller set in Half-Step Mode) So you need 400 Steps to get the motor to spin around once. The Direction signal changes the rotation Direction of the motor. (CW/CCW) The motors hookup to the controller using the same gauge wire the motors come with.
Now we have the motors hooked up and a parallel cable hooked to the computer. The supply is on and the motors a tight but not turning. We now need software to convert GCode files to motor movement. The software also lets us JOG our motors back and forth. This is where 95 percent of CNCers quite. Some get stuck in a loop upgrading their motors and playing with software. Debating steppers VS servos and so on! I call them MOTORSPINNERS!
The next step!
I have been in this hobby for over five years. I know what I am talking about! In order to learn CNC you will need a machine. All the REAL innovative CNC people on the internet started by building a Simple Cheap CNC machine from scratch to learn with. For some reason some of them don't want you to waste your time trying to build one. Why? You may have noticed I sell plans for simple CNC machines. There are only a few of us selling plans to build machines. The big money is in controllers and motors. I decided to go a different route. Why should you build a machine? It's FUN and REWARDING not to mention EDUCATIONAL. I know what you might be thinking! He sells plans, so he is telling me to build my own machine using the plans he sells!!! If you think this is true, then you don't know shit! For every hour I put into this hobby I make ten cents! I am out to save you time, money and heartache. I never tell people: You can try that! I either know or I don't. Even though I know most people who buy my plans will never build them, I still tell them if something is not going to work. They always want to make my designs larger! I could say: You can try that! and sell them the plans anyway. That's not me!
The real truth is building your own machine and getting it to work can not be matched by spinning some expensive motors on an expensive controller or by putting some motors on an existing machine. The ultimate hobby is building a CNC machine from scratch! Computer, Software and Machine all coming together. Only a few people ever make it to that level.
You need to decide what kind of machine to build. I get lots of messages from people who can't understand why one machine can't do everything! Well, we have cars,trucks and buses. All having a different purpose but all having certain things in common. CNC is the same way! You can learn the basics of driving with a car,truck or bus. CNC is the same way. Pick a machine and start learning. A CNC machine lets you cut out complicated parts while doing something else. It's a time saver when doing a large run of parts. You can call building the machine a hobby. It is also nice to have a use for the machine when it is finished. I use my Brute to make prototype circuit boards. One of my designs called the Piker became very popular. (No longer sold)
Here is an example of this whole mess. Lets say you are cutting out lawn art. Windmills, bird houses Whirlygigs and RC planes. You have wooden patterns. You trace, you cut. With CNC, the pattern is loaded into the machine as a GCode that the software translates into motor movement. You can change the size of the part in the software you use to draw your part. The machine does all the work! While the machine is working you can be gluing up or painting the parts.
A GCode file can be produced using a text editor. Notepad in Windows works just great. I learned how to make GCodes this way. I imported an example GCode into Wordpad. I then did some reading. I figured out what each command does. There is an easier way to make a GCode. You draw a simple outline in TurboCad (FREE version on the net or a $30 version from the store) save the drawing as a DXF file. Then using the "ACE" converter (FREE found inside CNCPro) you convert the DXF to a GCode file. You than need to RENAME the GCode with a TXT, TAP or GC extension depending on which CNC software you use. You can also convert the DXF to GCode using KCam and other programs. Knowing how to write GCodes using Notepad will come in handy for locating problems in your GCodes later on! Beware of people pushing expensive software that takes hours to learn. Buying a doctor's bag won't make you a doctor!
There are three software packages I have worked with. There are dozens more out there in a clogged market. I bought CNCPro for $150 years ago. It runs great in a Windows machine that is booted up in the MS-DOS mode. On your shut down screen select Reboot in MS-DOS mode. After you install CNCPro and make a shortcut, if you click on the shortcut, Windows will ask if you want to reboot in MS-DOS mode. The second program that I strongly recommend is TurboCNC. It costs $60 to register but it works for FREE! This program is undervalued!!! Runs on old DOS machines and it will run under Windows in MS-DOS mode. The third program is KCam by KellyWare. It runs in Windows. It converts DXF to GCode and it displays the GCode outline on the screen. You can set it up to have the same size as you machine. You can test the GCode before you run the machine. Kcam will also run the motors. The motors run rough because WINDOWS keeps interrupting the program. Still you must check this program out. It was designed for the beginner. It cost $100 to register. The DEMO runs for a month before some features drop out. Try before you buy! All software will run in DEMO mode.
Some people call them driversRight now the top selling low cost controller is the HobbyCNC UniPolar Chopper Controller. It comes in Kit form or you can have Dave assemble one for you for an extra charge. Most of my people use Dave's controller on my designs. If you want to scratch build and do some tinkering I sell a booklet for a simple UniPolar Controller called the Perf-X. Not a beginners project but a neat adventure for scratch builders.
The more you read the more you will learn. If you want to learn CNC get used to reading and reading. In most cases you will have problems other people have not seen. Everybody seems to make their own CNCHell.
Do Lots of Reading