What cad and cam programs work together well.

[jerryrigge]

Hi all,

I am using a MP3000 THC on my newly built plasma table. Things seem to be working as advertised but I am unable to consistently process my dxf files to Gcode. I have tried Turbocad, Deltacad,Coreldraw and DWGEditor. I have used Lazycam and Sheetcam. The files often appear blank in the cam program or have hundreds of segments on 4 inch of travel.

This has been the most difficult part of using CNC for me. At my last job we used Artcam to create the drawing and generate the Gcode. It was wonderful and worked without issues almost everytime. But I cannot afford Artcam now.

I am hoping that someone can tell me what cad program, file format(and version) and what cam program will work together consistently to produce usable gcode. What works for you?

Thanks for you time.

Jerry Rigger

[jemmyell]

Hi, please try the DXFTool for CorelDRAW. You can get a free trial copy at http://www.coreldrawtools.com - it works well with SheetCAM.

-James

[Bubba]

For Sheetcam, the recommended dxf type is Rel 14

Later versions dxf can cause problems.

[jerryrigge]

This is useful information. I have the dxf tool for Corel but I was hoping to use a CAD program because I would like to do other design work in CAD. But if Corel is what works best then I will give it a try.

There must be lots of people that have figured out exactly how to consistently go from dxf to gcode. I have spent a week just experimenting with different ways and have not figured it out yet.

I will try to use the version that was mentioned in on of the replies and see if that give results. I will be checking back for any more tips that anyone posts.

Thanks,

Jerry Rigger

[Bubba]

Jerry,
I think you might be happier with cad based generation. Over on another forum dedicated to Sheetcam, most of the problems are non cad generated files. I did have problems until Les indicated the Rel. 14 version. Not all dxf files are created equal, not even from autocad who formulated the "standard"!

[Torchhead]

It all depends on what type of cutting you are doing. For geometric shapes (brackets, plates, etc) CAD works fine. The challenge begins when you start wanting to do decorative cutting. Example: Pick a Truetype Font, Kern it out, wrap it around a circle or along an arc and then place some vector based clipart in the center and tie it all together.

To do the decorative stuff it helps to have a tool that will import virtually any file format (Vector or Bitmap), so you can use any of thousands of clipart sources, and edit those objects and blend (weld, trim, intersect) them with other objects (like the text you just wrapped on the circle. Most of the really good vector art (like at www.VectorArt.com) is in AI and/or EPS format, neither of which any CAD program will import. The "Drawing" type tools that are the standard in the art. illustration and sign world are CorelDraw and Adobe Illustrator. They are made to deal with complex vector artwork and operations quickly and easily.

Both packages have one weakness in that, while they will import a DXF, most do a poor job of export, turning the nice smooth curves they use internally, into hundreds of tiny line segments. Enter DXFTool for Corel. It's a replacement DXF export filter for CorelDraw (Ver 12 and newer) that preserves the Arcs and circles in the export. It imports perfectly into SheetCAM. We have thousands of drawings we have done over the last 6 years (all in native CorelDraw CDR format) that have been imported and cut with SheetCAM and MACH.

Dirty little secret: CorelDraw also works quite well for most CAD type drawing since you can work to more than 4 decimal places of precision and it has some nice drawing tools like object snap, gravity snap, node type display, polyline drawing and tracing functions. It will import a bitmap (scan, web image, photo) and let you setup a layer and trace it so you can easily cut things like logos and things not in the clipart collections. It supports Layers, and lets you bring in drawings and overlay them to do accurate layout for things like panels and mating brackets.

The DXF Format is "owned" by AutoDesk [AutoCAD] and unlike things like EPS, AI, WMF, HPGL and other "standards" they have no reason to make it backwardly compatible or to timely publish changes when they release a new version. Most third party imports only support a sub-set of the methods in the format. Some of the older versions do not allow for polyarcs (continuous arcs). The irony is that a file format that is not standard and does not remain constant has become the "Standard" for CNC file transfer. Step outside the CNC world to the computer art and sign making world and DXF is not even on the list of standard file types.

So again, it depends on what you cut and what software you are comfortable with. If you have been using a CAD program for years then stick with it. If you don't know how to even begin to draw in CAD than the learning curve is not any steeper for a Drawing program than for CAD.

Tom Caudle
www.CandCNC.com

[warrenb]

Ideally you should do your designing in the CAM package you produce your gcodes. I may ruffle feathers here but bobcad V23 has been good to me and produces clean geometry and G code. I also import Corel parts with no problems. Something that may be happening is check to make sure your geometry is not on different layers or level that get filtered out of import commands. I'm limited in my opinion though because I only use two programs. BobArt and VX CAD CAM. I let Bobart produce my artsy fartsy stuff and use VX for the high end stuff.

Good luck

Warren