# Learning CNC



## Steve M (Mar 3, 2014)

Hi,
I would like to learn and perhaps use CNC.  I am wondering how to go about teaching ti to myself.

I have had a modicum of computers, programming, and electrical engineering by education and exposure in an aircraft repair depot and aircraft design/development.  I am also retired and live 60 miles from the nearest tech school.  I have a wood shop and machine tools, though I am much more experienced with wood than metals.  Software and software apps don't phase me.  KNowledgeable with drawings and blueprints.  Been a little slow at learning Sketchup, however.

Open for any and all suggestions.

Steve in Central TX


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## xalky (Mar 3, 2014)

Learning CNC is a lot like learning a language. Many of the machines speak a different language. AN analogy: You don't want to learn spanish if your machine speaks russian.

I believe it's important that you know what you want to do first, So that you can narrow down the type of machine you'll be working on. 

The first step in learning CNC is learning the right CAD program that can export files in a format that your CAM program can understand.

The CAM program interprets your drawing files into usable tool paths that your machine can use to machine the part.

The machine you chose and the amount of money that you want to spend on software will largely dictate which software you will be using.

Mach3 seems to be the CAM program of choice for the home CNC machinist because it's pretty cheap and yet powerful enough for most things.

Mach3 can import DXF, HPGL, or Excellon files. SVG is another file format that Mach3 can read. SVG is largely a graphics type file (think art) .

The learning curve is steep, especially if you have no prior experience. It's not rocket science, but it is a bit like learning a new language. 

Marcel


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## cjtoombs (Mar 3, 2014)

I started out writing G Code programs by hand for simple parts.  It lets you learn what the different commands do.  Setting the part up and setting the zero on the machine is one of the first things you will need to be able to do, and you will have to do it for every part.  If you set your program up with the zero point in the upper right hand corner, you will need to zero the machine on that corner of your stock so the program will start there.  I have a Tormach 1100, which has a very good manual, so that helped.  The "conversational programing" options available in Mach 3 are also available and help in making simple parts.  I did quite a number of projects using the hand coding and conversational programing before I moved on to CAD/CAM.  I was already using Turbocad, so I just bought their CAM plugin and started using that.  CAD programs take a while to learn, so if you don't have any experience with them, don't expect to jump in and start making stuff quickly.  Besides the CNC technology, you will need to learn metal machining, specifically speeds, feeds and how much your machine can comfortably take off in one whack.  Use cheap HSS end mills, as you will ruin many of them.  You will run them too fast and burn them up, take too deep a cut and break them off, crash the machine and break them.  CNC machines are absolutely fantastic at ruining expensive cutters.  I think the likelihood of a crash is directly proportional the cost of the end mill in the machine.  Anyway, good luck and have fun.


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## sinebar (Mar 3, 2014)

I also think that it is important to learn G-code by writing simple programs and just as xalky said, you must know the language your machine speaks. So you need to plan your path to learning and using CNC accordingly. 

To help toward that end, I recommend books by Peter Smid. In particular, the "CNC Programming Handbook"


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## SEK_22Hornet (Mar 3, 2014)

I have not looked at this site yet - just ran across it. Looks like it might be a good resource to learn about G-code.  You might take a look and see if it helps you get started. G-code is one of those languages that has a few basic commands, but many different "flavors", since controller manufacturers implemented it in slightly different ways. The basics will give you an understanding of how it works. It also has a terminology all it's own like modal and non-modal, transforms, profiles, pockets, etc.

http://www.cnccookbook.com/CCCNCGCodeCourse.htm

You also might look at the MACH3 site and the Planet-cnc website to get an idea of what the machine side looks like. 

http://www.planet-cnc.com/
http://www.machsupport.com/software/mach3/


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## Ray C (Mar 3, 2014)

Try visiting this site and sign-up for the online tutorials, which are very good...

http://www.grzsoftware.com/

No affiliation with this place but, the tutorial will help you get your head wrapped around the concepts.

Ray


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## bkcorwin (Mar 3, 2014)

xalky said:


> Mach3 seems to be the CAM program of choice for the home CNC machinist because it's pretty cheap and yet powerful enough for most things.
> Marcel



I would say mach3 makes a fine controller, but relying on it as your CAM package is very limited.  It has wizards which can do quite a bit, but in terms of non wizard tool path generation, I'd look elsewhere.

For simple 2d operations vectric cut2d does a pretty nice job generating code and has a mach post processor.  

BUT back to the original question.  For learning CNC MACH would be a nice program to have as it allows simulation of gcode you write.


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## xalky (Mar 3, 2014)

bkcorwin said:


> I would say mach3 makes a fine controller, but relying on it as your CAM package is very limited.  It has wizards which can do quite a bit, but in terms of non wizard tool path generation, I'd look elsewhere.
> 
> For simple 2d operations vectric cut2d does a pretty nice job generating code and has a mach post processor.
> 
> BUT back to the original question.  For learning CNC MACH would be a nice program to have as it allows simulation of gcode you write.


 I apologize. I misspoke. Mach3 is not a CAM software. My bad. I use Sheetcam for 2D plasma cutting as a CAM package.


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## freeidaho (Mar 5, 2014)

Steve,
Whatever you do, read/watch this thread front to back.
[h=3]CNC from sketch to part the way I do it[/h]
It is a sticky at the top of this forum.  It is great ! ! !

kr


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## Hawkeye (Mar 5, 2014)

Another good reference is this thread. http://www.hobby-machinist.com/showthread.php?t=12278

The real content starts around post #21.


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## mkeller (Mar 6, 2014)

Your local technical college probably has a cnc class as well.  Should teach you all of the basics that you can put towards your specific system.


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