Well there are lots of variations, mostly it adds sulpher to the mix.
When sulpher is present in the steel it cuts easier, as in high sulpher
Chlorine is another additive that works at a lower temp than sulpher oils.
However the job you described may have been helped better by a spray
of cool mist. Bronze especially in deep hole drilling is very troublesome
without the mist.
Chlorine oil... cut max 570 E.F Houghton
Best for stainless and bronze
Costs a little...does a lot...
Logic says that it doesn't reach the very cutting point. It reaches
just about everything else tough (including your clothes). The likely
benefit is that it helps the chips/swarf slide against the surfaces
above the cutting point easier, where it bends, thereby reducing
pressure on the points.
With deep holes, I find that the surface tension actually makes the
chips stick in the flutes, but the advantages outweigh that
But cutting-force analysis shows that lubricants sharply reduce cutting
force in many cases.
This subject has been studied in some depth, beginning with research at
Carnegie-Mellon Univ. around 50 years ago, and continuing with studies by
Dr. Eugene Merchant at Tempe Univ., and elsewhere. If you talk to one of the
top engineers at Sandvik, Kennametal, or one of the other biggies, they can
direct you to the research info. There also are several knowledgable people
at Univ. of Ohio, Perdue, and some other universities where they do academic
research on metalworking manufacturing.
There are several mechanisms by which cutting lubricants lower cutting
forces, alter the geometry of chip formation, improve finish, and so on.
What logic? Remember all it takes is a monolayer to affect how
the cutting happens. That's not much, and right near the
cutting there's a storm at work all the time.
Also, when you say 'the very cutting point' you are missing
the issue that cutting doesn't just happen at a single location
in space. The deformation, chip separation, and chip flow
really do occupy a larger volume than just a single point.
So the real question is, how much of the cutting process is
devoid of even a monolayer of cutting fluid, if the entire
rest of the tool is coated or flooded?
Consider that temperatures get hot enough to vaporize the
oil - which means that now there is oil vapor permating the
work as well.
please reply to:
In many, if not most, cutting situations, the 'cutting point' doesn't
actually do the cutting anyway. This is obviously true of negative rake
or zero rake tools, which work more by fracturing the work in front of
the tool, but is less obviously true of positive rake tools also. There,
the tool acts more like a wedge, prying material out of the work. The
fracture in the work still occurs some distance (a SMALL distance to be
sure) in front of the cutting tool. The face of the cutting tool tip
(point) may not even be in contact with the work (at a microscopic
level), with the chip first contacting the tool part way up the rake
slope. The chip is 'peeled' upward, tearing the material AHEAD of the so
called 'point'. This is the region in which the cutting fluid may aid in
material failure and separation.
The lower face of the cutting point will ride on the work behind the
cut. Considerable friction (heating) can still occur there, as well as
at the point of chip contact. As has been stated, even a thin layer of
fluid at those points can substantially reduce friction, heating, and
chip 'welding' problems.
"Cutting fluids play a significant role in machining operations and
impact shop productivity, tool life and quality of work. The primary
function of cutting fluid is temperature control through cooling and
lubrication [Aronson, et al., 1994]. A fluid's cooling and lubrication
properties are critical in decreasing tool wear and extending tool
life. Cooling and lubrication are also important in achieving the
desired size, finish and shape of the workpiece [Sluhan, 1994]. A
secondary function of cutting fluid is to flush away chips and metal
fines from the tool/workpiece interface to prevent a finished surface
from becoming marred and also to reduce the occurrence of built-up
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