Re: [CAD_CAM_EDM_DRO] Re: Re: Resolution and surface finish

Fred Smith wrote:

> >Fred Smith wrote:
> >
> >> Often in aluminum a conventional cutting
> >> direction will result in a better finish as climb milling pulls the
> >> chip back & it gets crimped between the tool & the work, making a
> >> nasty finish.
> >
> >Are you sure about this? I always climb mill for best finish.
> >My experience is that conventional milling is the direction that
> >causes recutting of chips and bad surface finish. The technical
> >books also confirm this with drawings showing why that is so.
>
> Well if I wasn't sure do you think I would have posted it? Maybe you're not doing it right if you "always" do it the same way. What you say is usually, though not always, true in steel. It is even less often true in aluminum. Maybe the best way would be to try it and see if it improved the cut.

Back in the days of manual machining, I tried it dozens of times a day, as
I made a cut going one way, then another cut going back. I have rarely
seen a case where climb milling produced a poorer cut than conventional.
I can see a case where the chip is definitely blown off the cutter with
high pressure flood cooling or something, where conventional might give
better finish. But, especially in aluminum, I always have chips spinning
around and getting recut.

Anyway, with my machine (Bridgeport), my tools and my materials
(6061, 2024 mostly), I absolutely, without any question, find that climb
milling gives excellent finish, and conventional milling gives a LOT of
welded on chips, and anywhere from a rough finish to something
resembling a wood rasp! This depends on the material, feed rate and
cooling, of course.

Jon