Re: TANGENTIAL?

Hello,

Many controls "know" which direction they are "headed".

The arcTANgent gives this, even in "swept" arc algorithms... Add some
boundary checks and initialisation code and you can always know a
direction delta angle. This can then be used for tangential axis
moves and trajectory planning.

The EMC 274NGC interpreter contains a bit of code to deal with this.

FWIW, the free DanCAD3d download (www.metalworking.com) contains the
program DanPLOT, which supports the C axis required for tangential
cutting. I have to agree with Chris, that for all but small
letters/designs, the dragknife works nearly as well. But I don't know
where he gets them with holder for 100 bucks!

Hope this helps,

Ballendo

P.S. Dave, the errors are usually around the 0 degree position. (0
(up) and 270 (down) don't present any problem. Boundary checks
assumed.

--- In CAD_CAM_EDM_DRO@y..., Dave Lantz <dlantz@a...> wrote:
> I just ran thru the BASIC math of it... and i believe i concure..
however
> you'd have to have everything in incrimental... EXEPT the
tangential axis..
> if i understand it right???
> because you'd need a X value and Y value of the next point to
calculate the
> angle, then do something like
> the TAN of theta = Y/X... and do some multiplication to derive the
steps of
> a steper into degrees (or radiuns... ug...)
> ???post processor???
>
> here is a thought.. what would happen if you go straight up or down
> (incremental X value of 0) aren't you going to have an error? you'd
need an
> exception stating that if x=0 then theta is 90 if y >0, or 270 if
y<0,
> right?
> ok... it also wouldn't know which direction to rotate to if Y=0
also...
>
> -----Original Message-----
> From: art [mailto:fenerty@h...]
> Sent: Sunday, April 28, 2002 9:13 AM
> To: CAD_CAM_EDM_DRO@y...
> Subject: Re: [CAD_CAM_EDM_DRO] TANGENTIAL?
>
>
> Thanks Doug: (your checks in the mail)
>
> Wouldn't it be just a simple matter of calculating the next
trajectory
> direction and rotating the engraver knife to the right direction
prior to
> the move...of course, all arc's would have to be converted to
segments prior
> to doing this...
>
> Or is there something I'm missing here? Is a tangental cutter
just a
> rotational axis?
>
> Art
> Master5 Software
> http://users.andara.com/~fenerty/master.htm
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