From computer to CNC path

[Mr Ron]

In an effort to understand the CNC process, I created this flow chart. Please examine it and see if I'm on the right track or am I missing something, particularly on the software side.

CNC flow chart.jpg (19.28 KiB) Viewed 8567 times

[Dave_C]

Ron,

The drawing is schematically correct. There are lots of variants on how it gets from a drawing to G Code. Today the drawing tools are almost a profession in themselves as are the CAM programs. (Not to mention the cost being prohibitive for home shop use)

Would I like to have a 3 D modeling program? Yes but am I too old to learn how to use it effectively? Probably.

CAM programs don't seem to be much easier to learn and I've worked with computers in my work since the 70's so its not a lack of computer skills that keeps me behind the 8 ball it is the step learning curve.

G Code is simple in comparison! (or was for me)

Dave C.

[Mr Ron]

Thank you. I have Autocad on my computer and can draw anything with it. Do I go from there to "G" code, or to a CAM program? Does the CAM software automatically generate the "G" code? I don't intend to go 3D. I want to just use 2-1/2 axis, not 3.

[Dave_C]

Ron,

The general path is Draw it first, then save it in a format you CAM program will accept such as an IGES file and then the fun starts.

CAM programs need to have a tool table just like the machine your going to use except it does not need to know the offsets, just the tool dimensions. (diameter for mills, number of flutes, tool tip radius for inserts on lathe tools and tool widths for goroving or cut off)

Once you get the file into the CAM program you will start selecting lines to cut, tools to make the cut, raw stock size and so on until you get the whole part defined with a cutting tool path. (many paths in most cases)

After all that is done, you can then have the CAM program create the G Code for you to do all those tool paths you just defined.

It takes three things to do all these steps. A Drawing program, A CAM program and A CNC program to run a machine.

And good nerves to watch the first run! (Usually with no tools in the machine)

Dave C.

[Gary Armitstead]

Ron,

In my previous life before retirement (about 2003), I made drop and press forging dies for the forging industry. All manual hydrotels through most of my career until the early 1990's. Then it was all cad work, toolpathing and running Seeburg NC mills and Haas horizontal mills, 3 and 4 axis.

My software was MasterCam.....a fairly high end program for drawing geometry, surfacing and solids. I started using it in 1990 and STILL use it at home today. AND I'm still learning today.

The nice thing about MasterCam and similar software is that you do your drawing and then use the toolpath module to generate your particular toolpaths to make the part or parts. Once you are satified that the toolpath will do what you want it to, you go to the "post processor" module. This is the module that generates your G codes and M codes. First it is processed as an NCI (Numerical Control Intermediate) file and then it processes that file into your finished NC file that actually activates the machine and controls the cutter or cutters. The days of "proofing" a toolpath in the machine are long gone. Very, very old technology even 15 years ago. There are programs within the cad/cam software that runs the toolapths and proofs the code. Actually has an animation system that shows the steel or material being cut in 3D and rendered as a steel block.

Post Processors can be very expensive in their own right. I have a post to send code to a Bridgeport Boss Bandit II. In fact, their are two of us now making 1 1/2" Baldwin Electric locomotives (similar to the project run about 25 years ago at Los Angeles Live Steamers). I draw the parts and toolpath them here in Burbank and then send the completed NC post to my buddy in Lake Tahoe by email. He runs the parts on his Bridgeport. Easy peasy.

Ain't technology great??

[DICKEYBIRD]

Hi Mr. Ron,

Download ACE Converter (free, no limits) http://www.dakeng.com/ace.html to convert your 2D .dxf's to G-Code. I used it for years with my CNC router and still use it at times on my little CNC Sherline mill. It's simple & pretty easy to use (has to be if I can use it.)

You can download Mach3 for free and actually simulate your training projects onscreen. The free download has some limitations but not enough to get in the way of the learning curve. The Mach support forum is full of fellows that are eager to help even before you decide to purchase. I used the heck out of them for almost a year before I made some money on a big project & my guilt overcame me.

Good luck & keep on plugging away! I'm 67 & still learning this stuff & having fun (most days.)

Milton

[Mr Ron]

Hi Mr. Ron,

Download ACE Converter (free, no limits) http://www.dakeng.com/ace.html to convert your 2D .dxf's to G-Code. I used it for years with my CNC router and still use it at times on my little CNC Sherline mill. It's simple & pretty easy to use (has to be if I can use it.)

You can download Mach3 for free and actually simulate your training projects onscreen. The free download has some limitations but not enough to get in the way of the learning curve. The Mach support forum is full of fellows that are eager to help even before you decide to purchase. I used the heck out of them for almost a year before I made some money on a big project & my guilt overcame me.

Good luck & keep on plugging away! I'm 67 & still learning this stuff & having fun (most days.)

Milton

Does the ACE converter also require the MACH3, or is it one or the other?

[Dave_C]

Milton,

I downloaded ACE converter and it does not appear to work for lathe work. Only mill, router, plasma and the like. Is that right?

Dave C.

[DICKEYBIRD]

Does the ACE converter also require the MACH3, or is it one or the other?

ACE is a simple program that just converts your 2D .dxf's to basic G-code for 3 axis routers or mills. The G-code is then loaded into your machine's controller software. Mach3 is one type of control, LinuxCNC is another plus there are many "professional" commercial controls.



Sorry Dave, I should've mentioned that ACE is for 3 axis machines only. I have a CNC lathe and mostly use the built-in wizards in Mach3 Turn for my jobs. I was very lucky and bought DolphinCAM for lathe used very cheap and am still learning it. It's powerful & fairly easy to use but I usually take the easy way out & use the Mach wizards. Mach does come with "Lazy Turn", a simple lathe CAM program but development for the program stopped several years ago. It has a sub-forum on the Mach site and people do use it successfully. I gave up when I got Dolphin.

[Dave_C]

Milton,

Thanks for the feedback. I'm using the wizards in Mach 3 as well for now. There are things I would like to do in the future that the wizards don't do but learning a CAD/CAM program is a steep learning curve.

I've been playing with the BOB CAD software since you can download it as s demo for free. The Cad part is hard but the CAM part is pretty much run by wizards and is pretty easy to learn.

Anyway,, thanks,

Dave C.

[Mr Ron]

Thank you for your assistance in my understanding of this CNC train.

[hwboivin3]

There is a free AutoCAD macro that will generate a 2d g code also. I use it a lot !

CncPath macro


http://www.freecadapps.com/swdetails.ph ... lor=ffffcc

It says it's good for 30 uses, but resets over and over.