Question About the Collective Interaction of CNC Components?

[MxRacer19]

Hey all,

My name's Matt and I'm new to this site. I've been researching the idea of building a small CNC mill for quite a while now, but in all my reading I have yet to come along on the overall picture of how each individual component interacts with one another.

From piecing together everything that I've read, I understand the system to function as follows:

A part is designed in some type of CAD software. From there, the design is exported to some type of CAM software, which takes the design and turns it into code that the mill's system can understand (G-code). The G-code is transferred to the mill computer and a program like EMC2 or Mach 3 interprets the G-code. The interpretations are sent via parallel port to a breakout board. The board is powered by an external power supply. The job of the breakout board is to divide up individual signals along the X, Y, and Z axis. From the breakout board, each respective axis signal is sent to its own driver. The driver interprets the signal from the breakout board and sends the signal to the motor to step.

Is this correct?? I feel like I've read about so many different programs and intermittent steps; It's all jumbled in my brain and I'm trying to untwist everything.

If I've got this correct, are all types of drivers compatible with all types of breakout boards and most types of software? From what I understand, most everyone is using Mach 3. Is Mach 3 free?

Thanks in advance,
Matt

[atwooddon]

Matt, welcome to CNCZone. Your research and understanding of the interaction of all the components is correct. Of course there are many variations in components, etc, but you are correct with your general assumptions.

No, not all boards, controllers, steppers, servos, etc are compatible tho there is a lot of compatibility in like devices. IE, a lot of stepper motors will work with a lot of the controllers. It is pretty easy to find out if a particular stepper or servo will work with a particular controller. Easiest way, is do a search here on CNCZone or ask in one of the forums. Someone probably has tried your combination or knows for sure whether it will work or not.

Mach3 is a popular software tool for controlling the CNC machines. It is very flexible and very powerful. Support is great both from ArtSoft as well as the many, many users here on CNCZone. There are other software solutions like EMC2 that also work well. Mach3 is not free tho you can try it out for free on a limited basis (I think it has a limit on the number of lines of gcode it will execute) but you can get a good idea of how it works. Although it is not free, I think most will agree it is a heck of a bargain for the quality and functionality you get.

Hope this helps
Don

[ger21]

Mach3 is free for up to 500 lines of G code, but is $175 to run longer programs. A few other features also don't work when unlicensed (demo mode), but they aren't really documented. You can do quite a bit with 500 lines of g-code, though.

You pretty much have it correct.

Breakout boards come in many flavors. The most basic just provide screw terminals for the parallel port. More complex boards can provide many additional functions, like spindle speed control, and relays for switching devices on and off.

The breakout board doesn't really divide up the signals, as they already come from the parallel port on individual pins. It just makes it easier to connect the drives to the parallel port.

are all types of drivers compatible with all types of breakout boards and most types of software?

No. Mach3 sends step and direction signals, so you need step/direction drives. All stepper drives accept step and direction signals. And most if not all of the "breakout boards" you'll find are designed for step/dir.

A lot of industrial servo drives do NOT work with step/dir, though.

[vger]

Matt,

Welcome to the Zone, and to CNC. You have done your research well. You say you are looking to build a small CNC mill. Do you mean from scratch? Or are you wanting to modify something off the shelf like a Seig X2 (Harbor Freight 44991, Wholesale tool 3004-0136) as the starting point. By the way, if you are talking about a metal working machine, there is another section of the forum for that stuff. If on the other hand you are talking CNC router, then you are in the right place.

Steve

[MxRacer19]

Thanks for the warm reception and prompt replies! They were all very helpfull. I'm planning a small scratch-built MDF machine using ABEC 7 skate bearings and aluminum rail, much like the designs at buildyourcnc.com. The materials to be milled will mostly be acrylic and wood, although I'd like to design a machine that can handle light tooling in aluminum and brass for making small-scale models. I will primarily use the machine for milling acrylic parts for building fishtank accessories.

[mcphill]

You have a great grasp for a newbie, and I encourage your enthusiasm. However... You can "get in" pretty cheap, instead of spending a lot of time debugging and redesigning a first build. If it is in your budget, this is a great starter machine:

http://www.probotix.com/FireBall_v90_cnc_router_kit/