CNC Machine Controllers

Machine Controllers take your machining instructions from your G-Code and converts the G-Code into motion.  You are off to the races.  The controller interprets the signal pulses from your Control Computer and instructs the machine to move.

The Machine Controller is made up of various electrical parts.  Remember earlier that I said some electronic junkies flock to CNC.  This is why.  Machine controllers can be built if you are savvy with a soldering iron.  I myself am not.  I personally always default to ordering up a Machine Controller from one of my sources.Controller builders to me are electronic gods.  They mix power sources, match up Amp, Volts, etc into the item I need.

Generally, you can pick the number of Axis you want before they build the controller.  For example, if you are building a CNC Plasma Cutter you may want a two-axis controller.  Possibly a three-axis controller if you have a Torch Height Control.

If you have a milling machine or a wood router in mind, then a three axis is your ticket.  If you want to machine with a rotary axis, then you need a four-axis controller.  So on and so forth.

Here are some example controller prices Here are some prices you might see in the marketplace.  Most come with motor systems and cable as well.  Really, you purchase a whole kit at once if you go this route.  The other way to do it is to buy components and assemble it yourself.  I wouldn’t suggest this for the beginner.

Prices2 Axis – $1000–$3000 - Movement in the X and Y axis, dependent on the size of motors you order3 Axis – $1500–$4000 - Movement in the X, Y and Z axis, dependent on the size of motors you order4 Axis – $2000–$6000 - Movement in the X, Y, Z and A axis, dependent on the size of motors you order

Note: The A-axis is the rotational axis.  Why is it called that?  I don’t know.  It is also sometimes called the B-axis.  I have even heard it called the W-axis.  A-axis is the rotational axis around the X-axis. B-axis is the rotational axis around the Y-axis.

Buying a completed CNC MachineIf you purchase a CNC machine outright, it will have a machine controller as part of the package.  Everyone does it a bit different though.  Some try to make it a black box that only they can fix.  Other use commonly used components so you could repair it if need be.  You will just have to ask the manufacturer and see what they say.  My experience says they usually tell you that it uses common components that you can get anywhere if needed.  If something goes wrong, it seems you can only get the part from them.  You will have to decide.

Internal Machine Controller PartsThere are many different electrical components that go into a machine controller.  I won’t pretend that I am an expert on this.  Actually, this is one of the components I buy pre-made so I don’t have to do it.  If you are an electronics junkie you could build your own.  I know where my skills are at and it isn’t in assembling and understanding electronics.

Here is what I know about the guts of a controller.  There will be drivers.  One for each axis. 

Gecko Drivers seem to be the best value on the market right now with great support.  I have used Gecko drivers in two of my creations and they work great.  Next, is a processor to do the computing work.  A power source to power the controller.  Finally the external cableling that heads out to the motors at each axis on your machine.

There is more to it than just that, and I have probably left out some parts.  Those are the basic parts of machine controllers.

CNC Control PendantsI didn’t quite know where to put this section.  The Machining Chapter or Machine Controllers Chapter.  It ended up here because the pendant is almost always hooked to the controller.  Any pendant automatically gets a gold star from me.  I love them.  If you use one, I guarantee you will love it.

Pendants are a true lifesaver when machining.  They give you access to commonly used functions about anywhere you want them.  You can jog the machine to a new location.  You can zero out your axis with a click.  You can even control your machining speeds on the fly.  All pendants are different and are usually associated with a purchased Machine Controller.Pendants can be made.

There are a number of people out there that have pieced them together. Generally these are the electronic types of people involved with CNC.  They like this extra challenge.  Many of these home brew pendants actually come out very nice.  Many of these folks are proud of them and share their plans and component lists readily.  The trick is finding them.