Re: rough circle

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Fred Smith" <imserv@v...>
wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "afogassa" <afogassa@y...>
> wrote:
>
> > I think it has something to do with the look ahead, maybe it
> pauses
> > on short line segments enough to gouge the parts(movements gets
> rough)
>
> No, the files are 100% preprocessed. The Gen 1 controller has

about

> 50 blocks in buffer and Gen 2 is around 200. The absolute max

block

> throughput is about 300 blocks per second. A block is approximately
> equivalent to a line or an arc in G-code.
>
> There was a recent change in the arc interpolation setup. If you
> have downloaded a recent version and changed the circular
> interpolation to lines, the setting is persistent and you may

bounce

> up against the 300 blocks per second.
>
> You should only use arc to lines interpolation if you have

different

> leadscrew ratios on X and Y. If your ratios are the same, no

linear

> interpolation comes into effect and you will be able to process any
> arcs at 125,000 steps per second.
>
>
> > Maybe I should make the acceleration curve longer, but than, it
> > slows down the milling speed.
> > I'm not shure but deskcnc can not do a real interpolation,

(sends

> a
> > pulse out for x than y than z on each pin of the microprocessor)
> so
> > it sends like 100pulses on x axis waits it to finish, than 100
> pulses
> > on y axis than on z axis, if so it would have to be alot faster
> than
> > it is.
>
> No, all axes are simultaneously indexed.
>
>
> Fred Smith - IMService
> http://www.cadcamcadcam.com/hobby
>

thank's Fred,
If it can do all axis at the same time why there is no provision for
helical milling ? or interpolating three axis.
here is what happens, I'm using powermill to generate the gcodes
from 3d surfaces to machine a stearing wheel mold, finish looks good
at the outside radius, but at the center ofthe stearing wheel there
is smaller radius curves where I'm having problems with finish.
the code generated is all line segments not arcs and I have the same
resolution for x y z .