VW conversion to a CAM program

[ERK]

I have recently been asked to send one of my VWX files converted to a DXF so it can be used in a CAM software (I think that is the correct acronym). Basically the file will be used to program a waterjet. Has anyone on here done that before? Are there any issues with the conversion, or any of the tools that VW will use that might confuse the waterjet (IE a tool that VW has that the CAM software may not have so it will not understand)?

Thanks

[GWS]

Are you exporting many parts from one file or do the parts have individual files?

[GWS]

OK let's say you have one item in one file.

You will probably need to export the file as version 14 DXF or even 12 anything else will cause problems which can range from the water jet not being able to read the file to actually causing a crash....not very helpful.

Make sure, and this is really important, the view is in Top/Plan and nothing else as some CAD/CAM software can read on object on a 3D plane.

The outline or outlines must be single polylines or polygons, so if you modelling in 3D you will need to pick a view of the object and 'convert to lines' to create 2D object but beware as the 2D object can still be on a 3D plane as already mentioned.

Once you have your 2D lines you will have to compose them into one line or polygon.

If you do convert to lines you may want to smooth the curves by going to Modify>Smoothing and then pick an option I usually pick arc smoothing.

This is necessary as VW turns 3D arc or circles into many straight lines causing a faceted finish.

If you have any more specific questions, I'll be happy to try and help.

Edited April 7, 2011 by GWS

[ERK]

Thanks Guy, that answered my question perfectly. The curves & 3D were what I was was really wondering about. I know that in the past one company had issues with using the Spline function on Rhino, to where the nozzle would jump once the drawing had that used.

So correct me if I am wrong, to convert something that I have modeled in 3D, I would actually need to create multiple 2D views made from polylines to create a "safe" file to use (top, right, left and back views all in the "Top/Plan" view)?

[GWS]

You only need to create a DXF file for the view of the profile that you want cut, unless the water jet cutters are actually cutting a 3D object, which I'm not sure is possible.

In other words if you have a plate that is on the XZ or YZ axis, not lying flat on the ground plane, you would need to select either the right or front view so that you would be looking at it square on and then convert to a 2D outline.

Once you have got the outline make sure the view is set to Top/Plan before you export. The converted line or lines shouldn't change their orientation, if they do use the OIP to put them on the screen plane.

[ERK]

My mistake, I did not explain correctly.....

Waterjet is for the initial cutting, then the shaping & finishing etc will be done by CNC.

[Jim Smith]

Interesting, I've just heard (not seen) of a programme called LayFlat that will take a 3D model & convert it to a flat piece to be CNC stamped or cut from a piece of metal & incorporate the bend tolerances. Any one have experience with something like this?

[GWS]

No but sounds delightful!

[propstuff]

See also TouchCad for a (vectorworks friendly)program for developing solids.

(Not sure if it makes material thickness allowances etc)

[Benson Shaw]

I use waterjet all the time.

1. Different cutters have different software, patience and experience. rev12 dxf for some, rev 2010 for others. Ask what works best for them and try to comply.

2. Send a pdf for visual comparison. Note that the cutter's software may close a poly that you drew as open - your part gets split in two.

3. If this is the first encounter with this cutter, go there and look over their shoulder when they open your file. Verify everything on screen. If that's not possible, at least demand a cutting pdf from their software, equiv to a printer's "press check". Print it and overlay it on a printout from your software on a light table - check each shape.

4. Many cutters have software which only "reads" straight lines and arcs. Ask about this, and send some tests. Make your drawing from only these two kinds of elements. Yes, compose them into long polylines, but only with arc and corner points. No spline or bez points. The cutter may not even be able to do arcs, so will convert your curves into a bunch of short line segments.

5. Usually, fewer points are less expensive.

6. Most of my cutting is not so dimensionally critical. I draw a center line and ask that the cutter make the cuts centered on the vector with no offset (kerfing). You may need to adjust your drawing and/or identify which side of the line to cut on to control dimension. Talk to your cutter about this for each object. Note that a perimeter cut with two holes inside is seen as 3 objects by the cutter.

7. Last, and most important: This is teamwork, a relationship. It has lots of places where it can break down. Do some file exchange with the cutter. Maybe even pay for some test cuts (go to the facility, look over their shoulder, approve if it's good, take your laptop, resubmit revisions on the spot, learn to adjust things for success). When you have done this a few times, some of the supervision can be lost

It's a wonderful technology.

Good luck!

-B

[Benson Shaw]

Oh, more on the list:

Port out your VW drawing(s) to dwg/dxf, then port them back into a new blank VW file. Look for problems, especially stacked vertices, correct and do the export import again. See if problems are fixed. Then send that to the cutter.

-B

[ERK]

Great advice, thanks everyone!