AutoCAD14 "Splines" > G Codes ???

[DanO]

I have AutoCAD 14 drawings that contain 2D parts that use "splines" for the critical edge profiles.
I need to be able to convert the drawings to G Codes to run on a Machining Centre ..
What would be the cheapest program around to achieve this ~ if it can be done at all?
Any help would be greatly appreciated ...

[ger21]

Can you're machine cut actual splines? Or do you need it converted to many short straight segments? Do you have anything that can create g-code from .dxf's? If you save the drawing as v12 .dxf, the splines will be converted to a polyline with short, straight segments. Their is also a spline to polyline Lisp program freely available that will do the same thing, but will let you decide on the # of segments. You can get it here: http://new.cadalyst.com/code/browsey...?fullyear=2003

It's from December, 2003

[DanO]

ger21

I've got the guys at the engineering firm checking out what their Machining Centre is capable of (it has a Fanuc controller) ~ still waiting for a result ... But, as you have indicated, I doubt that it will be capable of handling splines or nurbs.

I have exported the file as a AutoCAD12.dxf and the splines converted nicely to very short polylines with a high enough resolution to do the job well enough.

So now I just need to find the best/most usable .dxf > G-Code program (for a newbie). Do you have any recommendations for that?

Once agian - thanks for all your help.

[ger21]

Look at SheetCAM. http://www.sheetcam.com

You might also want to download the Flashcut machine control demo software. It has a fully functional .dxf converter in it, and it's free. I think the website is http://www.flashcutcnc.com

[lerman]

I don't know of any software out there that does this, but I imagine it would be better to convert splines to multiple arcs than to polylines. Or, in the case of 3D splines, convert them to helices.

Ken

[ger21]

I thought I knew a way to do that, but it didn't work when I tried it. I'll try to remember what it was.

[DanO]

ger21,

I've just become aware of the G-Code exporter that your working on for AutoCAD ...
I'll have to download it and give it a go - it sounds just like "the ticket" to me.
I don't want to scare you ~ but if your looking for features to add to it, it would be good if it could convert Splines > multiple arcs > G-Code all within autoCAD?

[ger21]

I am looking for feature requests, but within reason. I'm writing it for me, so if it's something I might use, I'll add it (If it's not too hard)

The version I have for download in the other thread, only does polylines. Multiple arcs can be joined into a single polyline with the PEDIT command.

Here's a way to get multiple arcs from a spline, without leaving AutoCAD. I'm assuming you downloaded the Spline to PLine lisp. (If you'll be working with splines a lot, you should make a toolbar button for it.) Set the number of vertices as low as possible while not losing the shape of the spline. Once converted to a polyline, use the PEDIT command, and use the "fit" option. Then explode it and you'll have a bunch of arcs. Use PEDIT again, with the "join" option and connect it all back together. Export with my exporter.

The results you get using the "fit" polyline may not be what you want. You may be better off just using the S2P lisp with a higher vertex setting.

I'll have to look into seeing if I can get my Exporter to natively support the "fit" polylines. THat will be one of the last things I look at, though.