Re: [CAD_CAM_EDM_DRO] re:g-code parsers

> Les,
>
> I didn't know what all you were looking for, but I'm sure you get the
> idea. scanf() and sscanf() are std. 'C'. If you have a token, and you
> expect a numeric parameter, then "scanning" the token string for the
> float is a simple way to get the number out (or telling you if you
> didn't get it).

Alan,
Sounds like the much easier way to go!
All tokens (letters) will be followed by parameters(numbers)
as I understand. Therefore the first float (or integer) I get out
will be preceded by whitespace and its token and so on.
I will play around with it. (or just buy your code??)

>
> Did you pick up on the Modal groups? Example, you can only have a G0,
> G1, G2 *OR* a G3 on a line at one time, they are all in modal group 1.
> Similarly, group 2 is G17, G18 or G19. And you want to set a flag to
> say you saw a "move" group command, and at least one axis parm (X,Y,Z
> etc) to act upon.

I had done a search for all prep functions with coordinate parameters. Even
G72 and G73.... but I don't know how many
cam systems use it. I just know I am doing coordinated 3d moves. I must
study rs274d a bit.

>
> The sparse data and curve fitting routine sounds interesting, I wasn't
> going to go that far, but...

Well a large router has about 10^15 adressable points! But I
think I can get chordal deviations of less than .001" with most
moves with control points .01" or more apart with bezier curves.
I am having to time the routines though because the calculations are
involved for 3d. I did not write them. I think I can have them ready for the
old 628 long before it gives me an interrupt. I run it in velocity mode with
interrupt on breakpoint.
I can interpolate second order curves of course by commanding different
accelerations on different axes. But that is just a subset of the more
general third order b- splines.

At the Atlanta IWF show I saw lots of cnc routers but I was not too
impressed with the low and mid priced (<$100k) ones.
They were either slow or gougy. I need something better to get some labor
content out of my operation here. Heck most of them were just cutting
squares out of flakeboard or MDF. The best ones I saw were awe-inspiring but
way out of a small operators price range. I think they were NURBS based.The
drill is to avoid secondary sanding or finishing by more accurate tool
paths. Sanding/finishing is the number one labor cost for me by far. About
75%.

After a lot of work I have a platform that is stiff and repeatable to .001"
over a very large work envelope. I just need good software to take advantage
of that structure.

>
>

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.rabun.net/~leswatts/wattsfurniturewp.html