U.S. patent application number 10/314485 was filed with the patent office on 2004-03-25 for rotary metal cutting tool.
Invention is credited to Walrath, Richard J..
Application Number | 20040057803 10/314485 |
Document ID | / |
Family ID | 32505857 |
Filed Date | 2004-03-25 |
United States Patent
Application |
20040057803 |
Kind Code |
A1 |
Walrath, Richard J. |
March 25, 2004 |
Rotary metal cutting tool
Abstract
A rotary end-mill is disclosed having a deferential flute
construction with all individual flutes being unequally spaced
about the circumference of the cylindrical tool body at different
helix angles. The cutting edge of these flutes also face in the
direction of tool rotation
Inventors: |
Walrath, Richard J.;
(Scotia, NY) |
Correspondence
Address: |
John F. McDevitt
#626
2255 Par Lane
Willoughby Hills
OH
44094
US
|
Family ID: |
32505857 |
Appl. No.: |
10/314485 |
Filed: |
December 9, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60345761 |
Jan 8, 2002 |
|
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Current U.S.
Class: |
407/54 ;
407/63 |
Current CPC
Class: |
Y10T 407/1952 20150115;
B23C 5/10 20130101; B23C 2210/243 20130101; B23C 2210/202 20130101;
B23C 2210/54 20130101; Y10T 407/1948 20150115; Y10T 407/1966
20150115 |
Class at
Publication: |
407/054 ;
407/063 |
International
Class: |
B23C 005/10 |
Claims
What I claim as new and desire to secure by Letters Patent of the
United States is:
1. An end-mill metal cutting tool having a cylindrical body with a
shank end and cutting end, said cutting end including a plurality
of helical cutting flutes unequally spaced from each other about
the circumference of said cutting end, and said helical cutting
flutes each being oriented at a different helix angle with respect
to all remaining cutting flutes.
2. The end-mill tool of claim 1 having an odd number of helical
cutting flutes.
3. The end-mill tool of claim 1 having an even number of helical
cutting flutes.
4. The end-mill tool of claim 1 having a larger length shank end
than the length of the cutting end.
5. The end-mill tool of claim 1 having a shorter length shank end
than the length of the cutting end.
6. The end-mill tool of claim 1 having an intermediate shank end
with a cutting end at each end of said shank end.
7. The end-mill tool of claim 1 having a ball end cutting end.
8. The end-mill tool of claim 1 for performing a rough milling
operation on a workpiece, said end-mill tool having helical flutes
with an uneven cutting edge.
9. The end-mill tool of claim 8 wherein said cutting edge is
serrated.
10. The end-mill tool of claim 1 wherein the end face of the
cutting part includes a corner radius at the cutting end.
11. The end-mill tool of claim 1 wherein the radial rake provided
on the cutting flutes varies with respect to the relative hardness
of the metal being machined.
12. The end-mill tool of claim 10 wherein a higher radial rake is
provided for machining softer metals.
13. The end-mill tool of claim 11 wherein a lower radial rake is
provided for machining harder metals.
14. The end-mill tool of claim 8 having a ball end cutting end.
15. The end-mill tool of claim 1 having an outer tapered
contour.
16. The end-mill tool of claim 1 having a wear-resistant surface
coating on the cutting end.
17. The end-mill tool of claim 1 wherein the shank end includes a
flat locking section.
18. A cylindrical metal cutting end-mill tool having a shank end
and a cutting end, said cutting end having three helical cutting
flutes unequally spaced about the circumference of said cutting
end, the first helical cutting flute being angularly displaced from
the zero angle position on said circumference, the second helical
cutting flute being angularly tapered from the one hundred twenty
degree angle position on said circumference, and the third helical
cutting flute being angularly displaced from the two hundred forty
degree angle position on said circumference, said helical cutting
flutes also each being oriented at a different helix angle with
respect to all remaining cutting flutes.
19. The end-mill tool of claim 18 having a helix angle of
approximately thirty-eight degrees for the first helical cutting
flute, a helix angle of approximately thirty-five degrees for the
second helical cutting flute, and a helix angle of approximately
forty-one degrees for the third helical cutting flutes.
Description
RELATED PROVISIONAL APPLICATION
[0001] This application relates to Provisional Application Serial
No. 60/345,761 filed by the present applicant on Jan. 8, 2002.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to rotating end-mill
metal cutting tools and more specifically to a particular
construction of said machining tools providing significantly
improved performance when put into use.
[0003] A variety of end-mills for use with rotating milling
machines are well known and are being used. Depending on design,
such end-mills are generally used in right or left hand cutting
operations, spiral and center cutting operations as well as
chamfering operations, and the like. Conventionally, these
end-mills are constructed with different types of hardened steel as
well as tungsten carbide, including tungsten carbide inserts, and
are often given additional structural features such as a corner
radius at the cutting ends, tapered cutting ends, ball shaped
cutting ends, uneven cutting edges for rough milling operations
including serrations and still other edge contours. Likewise, these
end-mills can be provided for longer wear with wear-resistant
coatings including tungsten carbide, amorphous diamond and various
nitride compositions. It is still further known with end-mills
employing helical cutting flutes to vary the radial rake of the
cutting edges with respect to the relative hardness of the
particular metal being machined. In such manner a higher radial
rake is generally provided for machining softer metals while a
lower radial rake is employed for machining harder metals.
[0004] In U.S. Pat. No. 4,963,059 there is disclosed a rotary
end-mill metal cutting tool with a central axis of rotation
therethrough. Said cutting tool includes a cylindrical body with a
shank end and a cutting end, said cutting end including an even
number of helical cutting flutes being equally spaced in pairs
about the circumference of said cutting end. Said equispaced
helical cutting flutes are said to be disposed perpendicular to the
axis of rotation for the tool body with at least one of said
helical cutting flutes being disposed at a helix angle different
from the helix angles of the other helical cutting flutes. A
ball-nose end-mill having said helical cutting flute construction
is also disclosed in said reference.
SUMMARY OF THE INVENTION
[0005] The present invention provides a novel construction for
rotary end-mill cutting tools demonstrating unexpectedly superior
performance advantages. In comparison tests with several other
commercially available end-mills, the present end-mill construction
proved consistently superior in both profile cutting and slotting
procedures. Higher tool speeds with lesser noise during operation
were experienced with the present tool construction when machining
steel workpieces and is expected to exhibit superior performances
on aluminum workpieces.
[0006] It is an object of the present invention, therefore, to
provide an improved end-mill tool construction enabling higher
cutting speeds to be employed then with similar tool
constructions.
[0007] It is another object of the present invention to provide a
novel end-mill tool construction enabling better chip flow during
operation to reduce or eliminate flute clogging.
[0008] It is also an object of the present invention to provide an
end-mill cutting tool which greatly reduces the noise caused by
contact between the cutting tool and the workpiece.
[0009] It is yet another object of the present invention to provide
an end-mill cutting tool which produces an improved surface finish
on the machined workpiece.
[0010] It is a still further object of the present invention to
reduce machine spindle wear with use of the present tool
construction.
[0011] These and still further objects of the present invention are
achieved with an end-mill metal cutting tool having a cylindrical
body with a shank end and a cutting end, said cutting end including
a plurality of helical cutting flutes unequally spaced from each
other about the circumference of said cutting end, and said cutting
flutes each being oriented at a different helix angle with respect
to all remaining cutting flutes. In a preferred embodiment, the
cutting end of the present tool construction employs three helical
cutting flutes unequally spaced about the circumference of said
cutting end, the first helical cutting flute being angularly
displaced from the zero angle position on said circumference, the
second helical cutting flute being angularly displaced from the one
hundred twenty degree angle position on said circumference and the
third helical cutting flute being angularly displaced from the two
hundred forty degree angle position on said circumference, said
helical cutting flutes also being oriented at a different helix
angle with respect to all remaining cutting flutes. In different
embodiments of the present tool construction, a greater odd number
of helical flutes can be employed as can be various even number
helical flute constructions. It is only required for such other
tool embodiments of the present invention that the above specified
combination of structural features be maintained with respect to
unequal flute spacing together with having different helix angles
for the individual flute members.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a side view for a representative right-hand
end-mill construction according to the present invention.
[0013] FIG. 2 is a partial end view for the cutting end of the FIG.
1 end-mill.
[0014] FIG. 3 is a graphical representation for a cross section of
the FIG. 1-2 tool construction depicting unequal spacing of the
helical cutting flutes about the tool circumference.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring to the drawings, FIG. 1 depicts an end-mill 10 of
the present invention having a shank end 12 and a cutting end 14.
Said tool member does not further include retention or locking
means being included on the shank end of said depicted tool since a
collet or other type holder device can be employed to secure said
tool in existing milling machines. On the other hand, it is
contemplated that a flat recessed section can be disposed on the
shank end of the depicted tool for said purpose. Shank end 12 of
end-mill 10 is essentially cylindrical in shape having a circular
peripheral outer surface 16. Cutting end 14 of end-mill 10 includes
three helical cutting flutes, 18, 20 and 22, respectively, although
a greater number of said helical cutting flutes is contemplated.
Said depicted helical cutting flutes lands are identical in
physical size while being unequally spaced from each other about
the circumference of said cutting end on the depicted tool. For
example, it has been determined with such tool construction having
an overall three inch length, a 0.50 inch diameter and a one inch
length cutting end that flute 18 can be positioned approximately
one degree ahead of center as its joinder site with the shank end,
flute 20 can be positioned there approximately at the minus one
hundred twenty-one degree location and flute 22 can be located at
such joinder site at approximately a minus two hundred thirty-seven
degree location. Said helical cutting flutes spiral about the outer
circumference of said end-mill 10 with each flute having a cutting
edge 24 facing the cutting path 26. Flute 18 is further disposed at
approximately a thirty-eight degree helix angle with respect to the
central axis of rotation 28 for said tool member. Flute 20 is
similarly aligned at a thirty-five degree helix angle whereas
remaining flute 22 is again similarly aligned at an approximate
forty-one degree helix angle. The partial end view in FIG. 2 for
said FIG. 1 cutting tool depicts the circumferential spacing
relationship for cutting flutes being employed herein.
[0016] FIG. 3 is a graph for a cross section of the FIG. 1 tool
construction to help further explain change taking place in the
angular displacement of the illustrated helical flutes 18, 20 and
22 with length change in the cutting end of said tool member. Said
graph 30 includes solid lines representing a zero degree point 32
perpendicular to the central axis of the tool rotation 28, a one
hundred and twenty degree point 34 in said rotational path and a
two hundred forty degree point 36 in said rotational path. Dash
lines 38, 40 and 42 represent angular displacement from points 32,
34 and 36, respectively, and which has been shown said graph 30 for
the flute construction herein being illustrated. Said dash lines
further depict angular displacement for the individual flutes 18,
20 and 22 at the lowest point in the cutting end 14 of the
illustrated tool member. More particularly, dash line 38 indicates
a one degree ahead of center for flute 18 at such lowest cutting
end position. Similarly dash line 40 indicates a minus one hundred
twenty-one degree location for flute 20 while remaining flute 22 is
shown to have a minus two hundred thirty-seven degree location. At
a 0.1 inch distance in said flute construction up from such lowest
end position, the respective angular displacements are found to be
again plus one degree, minus one hundred nineteen point fourteen
and minus two hundred thirty-nine point zero 2 degrees. At a 0.2
inch further elevation point, the angular displacements become plus
one degree, minus one hundred seventeen point twenty-eight degrees
and minus two hundred forty-one point zero four degrees while at a
0.3 inch elevation distance mark the angular displacements are
found to be plus one degree, minus one hundred fifteen point
forty-two degrees and minus two hundred forty-three point zero six
degrees, respectively. It will be appreciated that the herein
illustrated angular displacement will vary over a wide range
depending upon tool size and shape, number of selected helical
flutes and selected helix angles possibly extending from about
twenty degrees up to about sixty degrees. Additionally, it will be
further appreciated that a suitable selection for unequal spacing
and unequal helix angle of all helical flutes in the present tool
member can also depend on such other considerations as the intended
machining use for said end-mill.
[0017] Comparative machining tests were conducted for the above
illustrated tool member. The performance of the above illustrated
tool member in profile and slot cutting of a hardened still
workpiece was compared with the cutting performance of two
commercially available four flute cutters now being used for said
purpose. In conducting such comparison, these end-mills were
operated at a cutting speed of 3000 rpm with varying cutter feed
rates. The profile cutting performance for both commercial tools
experienced considerable noise during operation at a feed rate of
24 inches per minute. Very little noise was experienced during
profile cutting at the same feed rate as well as at higher feed
rates of 40 and 45 inches per minute. Better surface finish on the
machined workpiece was also achieved with the present tool member
as compared with the surface finish produced with both commercial
cutters in these tests. The slot cutting tests with these cutters
demonstrated a like superiority for the present tool member. Thus,
both commercial cutters experienced significant noise during
operation whereas the present tool member experienced little noise
during the latter comparison at the same cutter rotation and cutter
feed rate. Similar superiority was achieved with the present tool
member when cutting an aluminum alloy workpiece at considerably
higher tool speeds. The present tool member further removed chips
well with no apparent re-cut or build-up on the workpiece under
mist lubrication conditions.
[0018] It is believed that the present tool geometry of
deferentially spacing the flute elements in the present tool member
with different helix angles breaks up the chatter harmonics
encountered during the milling process thereby lowering the cutting
noise ordinarily encountered during customary operating conditions.
Such improved operation compared with conventional end-mill
geometries imparts greater dynamic stability of the tool member
during the milling process with decreased cutting noise. Such
improved dynamic stability achieved with the present tool geometry
should permit greater depths of cuts to be made with stable
operation together with improved cutting productivity as above
demonstrated in the foregoing comparative tests.
[0019] While a representative embodiment of the present invention
has been herein described, it is to be understood that still other
embodiments of the present tool construction are also contemplated.
For example, left hand end-mills, reamers, tapered end-mills and
the like can also employ the present tool geometry with improved
cutting performance. Likewise a greater number of flute elements
than above illustrated can be employed to similar advantage,
including both odd number and even number flute constructions.
Consequently, it is intended to cover all variations in the
disclosed tool construction which may be devised by persons skilled
in the art as falling within the true spirit and scope of the
herein claimed invention.
* * * * *