Re: Machine flex; How much is to much?

I believe I heard that while machining steel, if the cutter is sharp
and the chips are burnt, you are giving the heat to the chips instead
of the tool or the work and is preferable.


--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
wrote:

> >What type or size of a machine can utilize a 1/2"
> >mill to its capacity?
>
> The Rong Fu and similar sized machines will run a 1/2" endmill.

They will pull a 1" endmill. The rong fu and similar mills will do
basically anything a Bridgeport does, just not as well. You are
talking a 4" tube column verses 2600 pounds of cast iron. I think you
have a misconception of the "capacity" of endmills. If you are
removing stock, you need a rougher. And if an roughing endmill is
1/2" diameter and flutes 1 5/8" long doesnt mean it can be buried in
the stock 1/2" wide and 1 1/2" deep and expected to remove it all in
one pass. It could be done but not for very long. The easiest way to
judge your cut is look at the chips. Are they thick? If so, Cut down
the feed. If they are thin and brown, the cutter is dull or the
spindle is too fast. They should be reasonable thickness and bright.
When a rougher is cutting properly it will emit a particular sound
that after practice and burning up a few you will recognize when you
hear it. A good spindle speed on a 1/2" rougher is about

> 800rpm and about 3 or 4 inches per minute, a 1/2" finish should be

around 1000rpm. Endmills with long flutes such as a 1/2" with 3"
flute length in steel are just wishful thinking and they are very
dangerous. You move up to a corner to take a full 3" cut with an
endmill like that and it can grab and walk around the corner, snap
and fly across the shop like a bullet. I've dodged a few of them
machining out the inner surfaces for rod end clevises for large
hydraulic cylinders. Thats shaper work and the shop I was working in,
someone higher up got the idea the shaper was obsolete and got rid of
it. The shaper is still a very useful piece of equiptment for many
machining operations. I have my own shop now and I have one. Long
endmills are intended for final cleanup and plastics only. A good
rule of thumb on a rougher in steel: never plow any deeper than its
width and make multiple passes. A "finish" mill is just that, it was
never intended for stock removal in steel although you can

> but, again not for very long. You can take a respectable amount of

stock out of aluminum with a finish mill using oil or tapmagic to
prevent the chips from galding to it, Kool mist is useless in
aluminum. The worst sin commited to an endmill is allowing it to
dwell against the part or feed it too slowly, spinning and remaining
stationary. It will dull it instantly. That squeal you hear is the
stock wiping the cutting edges right off. If its turning and not
cutting get it it away from your workpiece. The only way deflection
can be countered is beat it at its own game. Play the deflection to
your advantage. If you are machining taking a full cut not side
milling to the right of your line and the endmill is rotating
clockwise you know its going to pull towards the line. So stay off
the line 30 thou or however much you think it will deflect and you
will still be ok for your finish pass. When machining a slot with a
rougher, I always hug the right side going across then come back and

> machine the inside perimiter and it is there.
>
> Ron
>
>
>
>
> I posted the same scenario to the Mill/Drill group regarding cutter
> size and material, and received a similar response. I guess I will
> have to re-think the type of work that this machine is doing now.

You

> mentioned that you have used a 1/2" endmill that produced a shift

on

> a Bridgeport mill. Trevor
>
>
> > 1/2" endmill? Getting a 1/2" endmill to do the kind of work it is
> capable
> > of on a light weight machine is doubtful. You might plan on using
> smaller
> > cutters. When a larger tool like the 1/2" takes a significant

bite

> into the
> > work, it may deflect the machine enough that it won't return to

the

> same
> > position. I do this pretty routinely on my Bridgeport, but I
> really don't
> > think you want to use a 1/2" cutter on any machine much lighter
> than that.
> > (Of course, there are special cases where you use the big cutter

for

> > stiffness when working at the bottom of a pocket, and take very
> light
> > cuts with it.)
> >
> > Jon
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@a...,

timg@k...

> Moderator: pentam@c... indigo_red@q... [Moderators]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:

aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach
it if you have trouble.

> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be

a sister site to the CCED group, as many of the same members are
there, for OT subjects, that are not allowed on the CCED list.

>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING

THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........

> bill
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to

http://docs.yahoo.com/info/terms/

>
>
>
>
> ---------------------------------
> Do you Yahoo!?
> The New Yahoo! Shopping - with improved product search
>
> [Non-text portions of this message have been removed]