On Fri, 18 Feb 2005 12:18:40 -0500, Cliff wrote:

On Fri, 18 Feb 2005 09:07:45 -0800, Garlicdude
wrote:

Robert Salasidis wrote:

What kind of finish, are you getting now? How are you measuring it now,
and what type of finish are you trying to achieve, reallisticly?

I wish I had a profilometer, but I am just using the feeler type
gages, and can estimate I am getting about 0.4 um (about 16 u in).

I would like to double that if possible.


Robert, I checked my Machinery's Handbook, Surface Roughness Produced by
Common Production Methods, and IF your presently achieving a 16 finish
by milling your doing pretty well. I think to get a MEASURABLE 8 finish
would require a good machine, especially the spindle, and a solid
setup. Having said that wiper inserts, button style cutter, or a larger
radius on your present cutter insert will all help to give you a better
finish.

I'm a bit curious how he's using feeler gages to estimate surface
finish.
Perhaps he could post his feeds (in IPR), number of inserts, insert
nose radius, .......

One buys the 70$ surface roughness "feel" gages and compares -
strictly a qualitative measurement.

The exact details of my cut are

I am using an ISCAR HM90 F90AP 3" cutter with APCR1003 inserts

There are 11 insert position on the cutter, with a nose radious of
0.02"

I am cutting at a depth of 0.01", 1300 RPM at an 8"/min feed rate
(very slow to minimize the ipt)

When I speed up the feed rate, I get a worse surface finish.

My machine has a BT30 spindle, so a 3" cutter is tha largest that I
can use.