CNC punch usage

Technical Technical Discussion
#1

Hi CD,
I am not sure if I am using the right technical words so please forgive me for the first time.
My team has a sponsor that make part for us in a CNC punch machine.
To this day we gave to the machine operator pdf drawings of the parts we needed. It was not efficient at all because the operator had to copy the drawings into the machine. We assume we could save about a week in the build season by exporting the 3D models of the parts into a format which the machine knows. I know the machine is old but the operator told us it can read dxf files. We tried to do it without success. Probably we did not do that right, so I am looking for detailed instructions how it should be done.
I am also checking an option of programming the CNC by ourselves, It seems unnecessary because we don’t really know how to do it.
We are using NX Unigraphics 6, I know many of the FIRSTers don’t use it but I assume the instructions should be the same.

Thanks,
Yarden

#2

Most CAD programs have an “Export” command, usually under the “File” menu.

So: File->Export, and make sure to select the .dxf file type.

For programming the CNC, you’d need some form of G-code generator, unless you really wanted to program it command by command.

#3

We tried it. I will try it again with a test part. Can you explain me what is the dxf file? 3d model/2d model? as I mentioned the machine is old (very old), I don’t really know but it can be the problem maybe?

#4

DXFs are a 2d file that includes dimensional data. They’re used to transfer 2-d CAD data (usually to CAM/manufacturers). DXFs have been around for a while, but I guess whether or not they can read it does depend on the age of the machine (a machine from 1965 will not be able to read DXFs). In any case, they likely take the DXFs into a CAM (Computer Aided Machining) program instead of directly inputting it into the machine. The CAM program would take the DXF and (with the help of a user) turn it into G-Code, the actual instructions that run the machine. Basically all CAM programs should be able to open DXFs.

#5

How does your sponsor create their CAM files? Do they produce .dxf files from a specific type of modeling package? See what they do and perhaps be able to copy their process?

Also, when you say that you tried giving the operator a .dxf files without success, can the machine not read the files, is the scaling on the parts off, or something else?

#6

The machine could not read the file.
I searched some more info and found that there are several ways to make dxf files in NX, I don’t know what the difference is.
I think I will go with the computer to the sponsor’s machine shop and try again.

#7

Working with the sponsor with your computer setup will definitely help…they should be able to spot the problem. Good luck!

#8

Yarden,

I am not terribly familiar with NX in regards to exporting DXF files, but found this video tutorial. As Eric mentioned, it is an export operation; but you have some control over what you export. DXF files can be more than 2D. It is important to only export to a 2D (flat) version of the face/surface you want to manufacture.

Much like any other CAD system, DXF has different file versions (e.g. NX 6 vs NX 5, or SolidWorks 2014 vs SolidWorks 2013). Attached is a screen capture of what I am talking about. Where I work, we have an old machine that is used on rare occasions, but requires us to save the DXF as an older version (AutoCAD 2000/LT2000 DXF) in order for it to read the file properly.
It does not look like this option is built into NX, although I could be wrong, so you may have to download AutoCAD or similar to convert the DXF version. Creo (Pro/E) has the option for us to do this as part of the export operation - we can select 2010, 2007, 2004, 2000, 14, 13, or 12.

DXF options.png
DXF options.png1157×949 131 KB



DXF options.png
DXF options.png1157×949 131 KB

#9

I watched the same video, and learned that there are several dxf formats. NX has all the formats.

Thanks

#10

I’ve found AutoCAD R12 DXFs to be the most universal for importing into other software packages. Try that type.

#11

Another thing to be careful of is if you plan to form the sheet after putting it through the punch you need to either figure out the k-factors/bend deductions your shop uses and apply them appropriately when going from 3D to flat pattern or ask your sponsor to help you make the flat. Really it’s whatever will work the best for your sponsor - we just send ours the 3D part and they figure out what the flat pattern should look like based on their machines. If you’re only doing flat parts though, you’ll be fine :smiley:

#12

How did you even get your hands on NX?

#13

university…