Writing your own CNC Control Software

[mechona]

Does anyone one know what is involved in writing your own custom programs to control your CNC. I want to write my own software, but don't know where to start. Where can I read and learn about the above. I have experience with various programming languages, so that part should not be that difficult.

What I am trying to do is learn how to write a program that will control a CNC beam saw, and print labels real time with bar codes. I would then take the labels to a cnc and have it pull up the program.

I realize that there are programs out there that do this already, but I am interested in writing my own customized programs. I just need to be pointed in the right direction.

thanks

[ger21]

We use Cadcode to create barcode labels for a Schelling saw from optimized cutlists created with Pattern Systems Cut Planner. Here's how the process works.

Create a cutlist file that the saw controller can read which contains all the information about the machine programs, or .dxf file names in our case. Run that file through Cadcode, which converts all the .dxf files and creates a label (the barcode is the file name of the .dxf) and adds a pointer to the label in the cutlist.
Cadcode also creates a label file with all the info on each label. The labels layout is also designed in Cadcode. Then the cutlist gets loaded into the saw, and when cutting, the saw sees the label info and sends that data to another program at the saw which actually prints the label from the label file.

If you write your own control software, it can print the label itself.

This is a pretty big project, imo. Keep in mind that you'll need to interface with the PLC in the saw as well. You're looking at writing the equivalent of 3 or 4 different apps to do this.

[kanzure]

The first thing that you want to do is figure out what sort of connections to the CNC machine you are going to be using. I have no experience yet with these machines, but to my knowledge it is probably going to be something like RS232 or LP port stuff. So you will have to figure out how you want to do input and output, which is thoroughly documented in many places (MSDN for Microsoft application development, and GNU-related documentation is everywhere thankfully).

Your first step may be going to find a manual. Keep us updated as to how this turns out for you,

- Bryan

[mechona]

Gerry,

Can you attach a sample output file that Cadcode produces? or pm me one.

Maybe I can start an open source project. I know that this will probably take at least a year to code, but wouldn't it be nice to have a project where everyone can contribute, that is free.

I just think that the pricing on the software and the support is out of control. The software companies basically have us by the B#$ls. If I can I would like to try and change that.

[andy55]

take a look at EMC (www.linuxcnc.org), especially the Hardware Abstraction Layer or HAL.
That's a real-time framework that already has drivers for the parallel port and the serial port + a lot of encoder/servo hardware.
You can use HAL without EMC if you want to have your own user interface and not steer your machines using G-code.

[Switcher]

You might want to look into inpout32.dll http://www.logix4u.net/index.htm to hook into the parallel port.

http://www.codeproject.com/useritems/Inpout32_read.asp


.

[ger21]

I doubt he'll be using the parallel port. Most likely his saw has ISA or PCI motion control cards in it. Probably proprietary as well.

What kind of saw is it, btw?

I'll look at the files at work tomorrow. I think the label file is binary, and the cutlist file is the standard csv format that the saw accepts, with the label info added to one of the fields for each part. The saw control actually reads the csv file and converts it into it's own internal format before you can actually start cutting.

Don't you have any files that currently work with your saw to reference.

[Switcher]

Originally Posted by ger21 I doubt he'll be using the parallel port. Most likely his saw has ISA or PCI motion control cards in it. Probably proprietary as well. What kind of saw is it, btw? I'll look at the files at work tomorrow. I think the label file is binary, and the cutlist file is the standard csv format that the saw accepts, with the label info added to one of the fields for each part. The saw control actually reads the csv file and converts it into it's own internal format before you can actually start cutting. Don't you have any files that currently work with your saw to reference.

Open source project, & proprietary cards kinda defeat each other.

I guess a project like this might be good, If everyone is running the same hardware/software?

mechona,
Are you building a machine or retro?

I've never seen a "CNC beam saw", any links?



.

[ger21]

Originally Posted by Switcher I've never seen a "CNC beam saw", any links? .

http://www.schelling.sg/FLM.358.0.html
http://www.giben.com/eng/scheda_sez.asp?cod=7
http://www.holzher.com/seite86.htm

[Switcher]

Do the "CNC beam saws", move in "X & Y" only?

Is the blade height fixed (Z)?

.

[ger21]

The sheet(s) are held by clamps, which feed it in and out. The beam is a hollow channel that holds the sheets down while they are being cut. The beam also covers the top of the blade, and is used for dust collection on top of the sheet. The blade rises, makes the cut, then drops down and returns to the other end for the next cut. On ours, you can set a parameter for the blade height protrusion above the top of the material in the software.

I guess you'd call the saw carriage X, and the clamps Y. It's really a 2D machine as the blade is either up, or down.

Ours can also cut "windows", or square holes and notches. There's a different parameter for blade protrusion with this operation to accomodate material thickness and how much overcut you want in the corners.

There's a cutting speed parameter, and ours has optical sensors to move at full speed until it sees the sheet and then cuts at the desired speed. This also lets it stop after the cut, and only return to the other side of the sheet for the next cut, rather then to make the full travel each pass.