A metal cutting tool - European Patent Office

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European Patent Office
Office europeen des brevets
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EP
0 534
450
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E U R O P E A N PATENT S P E C I F I C A T I O N
(12)
(45) Date of publication and mention
of the grant of the patent:
29.04.1998 Bulletin 1998/18
(51) Intel6: B23B 27/04,
B23B 27/14,
B23B 2 7 / 1 0 ,
B23Q 1 / 0 0
(21) Application number: 92116426.5
(22) Date of filing: 25.09.1992
(54) A metal cutting tool
Metallschneidwerkzeug
Outil a couper le metal
(84) Designated Contracting States:
DE FRGBITSE
(72) Inventor: Wertheim, Raphael
St. Kiryat Bialik 27000 (IL)
(30) Priority: 27.09.1991 IL 99584
(74) Representative:
VOSSIUS & PARTNER
Postfach 86 07 67
81634 Munchen (DE)
(43) Date of publication of application:
31.03.1993 Bulletin 1993/13
(73) Proprietor: ISCAR LTD.
Migdal Tefen 24959 (IL)
(56) References cited:
DE-A-3 004 166
FR-A-1 115 922
FR-A- 2 244 590
DE-A-3 740 814
FR-A- 1 222 947
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Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give
notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in
a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art.
99(1) European Patent Convention).
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EP 0 534 450 B1
Description
This invention relates to a metal cutting tool of the kind
having a metal cutting tip which either forms an integral
part of the tool or is formed on a metal cutting insert
releasably retained in an insert holder of the tool. The
invention also relates to metal cutting inserts for use
with such metal cutting tools.
With such metal cutting tools, the cutting edge of
the tip is defined between a rake surface thereof and a
relief flank or clearance face and, in use, the cutting
edge and the portion of the relief flank adjacent thereto,
become rapidly worn and, where the tip is formed on a
replaceable insert, the latter must therefore be frequently replaced or rotated so as to index a fresh cutting
edge in position. Similarly, where the tip forms an integral part of the cutting tool, the tip must be frequently
reset or the entire tool must be replaced.
With such cutting tips there is generally specified
(by the manufacturers) a maximum degree of wear of
the relief flank after which replacement, resetting or
indexing must be effected. This maximum degree of
wear is usually specified in terms of the maximum width
VBmax of wear of the relief flank when measured from
the cutting edge. Thus, when the flank wear reaches the
specified maximum VBmax, the tip should be reset or
replaced.
It is well-known that one of the factors determining
flank wear is the hardness of the insert material. Thus,
the harder the material the less will be the rate of wear
and the longer the insert can be used before wear has
reached VBmax requiring replacement. However, this
hardness is directly related to the working temperature
and with rise of working temperature there is an associated reduction in hardness, with a consequent increase
in the rate of wear.
It is for this reason that, in the use of such cutting
tools, means have been provided for the fluid cooling of
the cutting insert in the region of the cutting edge
thereof.
In one known method of fluid cooling, the upper surface of the cutting tip or insert is sprayed with a coolant
fluid but it is found that the continued movement of the
chip over the rake surface of the cutting insert disturbs
the effective cooling of the insert by the coolant.
In another known method of cooling, a coolant is
passed through the cutting tip from the base thereof to
the upper rake surface. It is found in practice, however,
that the pressure of the chip on the upper rake surface
prevents the coolant from effectively reaching the region
of the cutting edge, and here again the efficiency of
cooling is limited.
A further method which has been employed has
been to direct a coolant through a duct formed in the
cutting insert or cutting tip, which duct emerges from an
aperture in the relief flank of the cutting insert. It is
found, however, that in order to ensure effective distribu-
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tion of the coolant liquid around the relief flank and in
the vicinity of the cutting edge, a number of such coolant
ducts must be provided and this, in turn, leads to a significant weakening of the insert. Furthermore, the penetration of the coolant is hindered by the narrow gap
between the relief flank and the workpiece.
It has also been proposed to direct a jet of a coolant
liquid into the space between the relief flank and the
workpiece, but this method is of very limited value, particularly when the tool involved is a grooving or parting
tool, seeing that the region between the relief flank and
the workpiece is of extremely limited accessibility as
compared with a turning tool.
FR-A-1 115 922 discloses a metal cutting tool with
an elongated internal coolant channel merging with a
short slanted section which extends towards the relief
flank and terminals in an opening located in the relief
flank.
It is therefore an object of the present invention to
provide a metal cutting tool having a metal cutting tip,
and which is provided with fluid coolant means wherein
the above-referred-to disadvantages are substantially
reduced or overcome.
It is equally an object of the present invention to
provide a metal cutting insert for use in a metal cutting
tool, provided with fluid coolant means wherein these
disadvantages are substantially reduced or overcome.
These objects are solved with the features of the
claims.
With such a cutting tool, whether having an integrally formed cutting tip or a replaceable cutting insert,
coolant is directed into the coolant channel formed in
the relief flank of the tip and is thus guided to and concentrated in the region of expected flank wear. Thus,
cooling takes place in the region of the cutting insert
where it is most required and, in this way, the rate of
flank wear is significantly reduced. This, in turn, reduces
the frequency with which cutting inserts have to be
replaced when the wear thereof has reached the maximum permissible level.
Various embodiments of metal cutting inserts in
accordance with the present invention will now be
described by way of example and with reference to the
accompanying drawings, in which
Fig. 1 is a schematic perspective view of a part of a
grooving or parting tool in accordance with the
invention and fitted with a replaceable insert;
Fig. 2 is a side elevation (partially sectioned) of the
tool shown in Fig. 1;
Fig. 3 is a schematic front elevation of a relief flank
of a replaceable insert in accordance with the
invention.
Fig. 4 is an enlarged view of detail A of the tool
shown in Fig. 2;
Figs. 5 and 6 are schematic views of differing forms
of inserts in accordance with the invention;
Fig. 7 is a schematic perspective view of a portion
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of a milling or turning tool fitted with a replaceable
insert in accordance with the invention; and
Figs. 8 and 9 are views of differing forms of turning
or milling inserts in accordance with the invention.
Referring to Fig. 1, there is here shown schematically a grooving or parting tool 1 having a tool holder 2
in which is wedge clamped a replaceable cutting insert
3 having a cutting edge 4 defined between an upper
rake surface 5 and a front relief flank 6.
Formed in the relief flank 6 and extending from a
base 7 of the insert 3 is an elongated recess 8 constituting a coolant channel, the recess being bounded on
either side by unrecessed portions 6a and 6b of the
relief flank 6.
A coolant duct 9 is formed in the insert holder 2 and
has an outlet aperture 10 which communicates with the
open, lower end of the recess 8.
As can be seen in Figs. 2, 3 and 4 of the drawings,
the recess 8 tapers in depth from the broadest depth in
the region of the base towards the direction of the cutting edge. The upper extremity of the recess is spaced
from the cutting edge by a spacing s. Fig. 4 shows the
prescribed maximum permissible extent of flank wear
VBmax.
As can be seen, s is slightly greater than VBmax, the
invention requiring that s is of the order of VBmax. Preferably, s lies substantially within the range of VBmax and
4VBmax with a preferred value of s being substantially
equal to 1.5VBmax.
On the other hand, the depth d of the recess 8 in the
region closest to the cutting edge should be greater
than or equal to the spacing s, the preferred value being
that the depth d is substantially equal to 2VBmax.
In the embodiment shown in Figs. 1, 2, and 4, the
relief flank 6 is provided with a single, centrally-disposed recess 8, the relief flank 6 being bounded on
either side thereof by unrecessed portions 6a and 6b
thereof.
Depending on the size of the cutting inserts, the
relief flank 6 can be provided with a plurality of such
coolant recesses 8 (as, for example, shown in Fig. 3 of
the drawings) and whilst the general considerations outlined above in connection with the spacing of these
coolant recesses from the cutting edge apply to the situation where a plurality of such recesses are provided,
the actual locations of the terminal positions of the
recesses adjacent the cutting edge may differ slightly
one from the other.
Both for the case where the relief flank is provided
with a single coolant recess and for the case where the
relief flank is provided with a plurality of such coolant
recesses, the overall transverse extent W of the
recesses, i.e. the sum total of the transverse dimensions thereof, should lie within the range of 0.2L to 0.7L,
where L (as seen in Fig. 3) is the transverse extent of
the cutting edge as a whole.
Where the insert is designed for use in turning (as,
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for example, in tools known by the trademark CUTGRIP), the tool, as shown in Fig. 5, is provided with side
cutting edges 11 and with coolant recesses 12 formed
in side relief flanks 13.
In the embodiment shown in Fig. 6 of the drawings,
coolant recesses 14 are formed at the corners defined
by side and front relief flanks and extend towards the
corners of the cutting edge. Such an arrangement is
believed to be advantageous, seeing that in practice it is
found that the magnitude of VBmax at the corners is
greater than in the central positions, and cooling which
is concentrated at the corners is believed to be particularly effective in reducing the rate of flank wear.
Reference will now be made to Figs. 7, 8 and 9 of
the drawings, where there are illustrated the application
of the invention to a turning tool. As seen in Fig. 7, a
turning tool 21 comprises a holder 22 formed with a
pocket 23 in which is fitted a turning insert 24. In the
case of this turning insert, clearance faces of the insert
24 are provided with a succession of coolant recesses
25.
In Figs. 8 and 9 are shown various alternative locations for the coolant recesses in the insert of the tool.
Thus, in Fig. 8 the recesses 26 are adjacent the insert
corners whilst in Fig. 9 the recesses 27 are located at
the insert corners. The recesses 25, 26 and 27 extend
as before to a region of the insert adjacent the cutting
edges and spaced therefrom by a spacing of the order
of the maximum permissible depth of flank wear. The
recesses extend into the base of the insert and communicate there with outlet apertures of coolant ducts
formed in the holder 22.
Whilst in all the embodiments described above the
coolant channels communicate with the outlets of coolant ducts formed in the holders and coolant fluid emerging from these outlets pass through the coolant
channels and are guided thereby into the region adjacent the cutting edges, in other embodiments (not illustrated) coolant fluid may be directed into the coolant
channels from externally disposed coolant ducts or nozzles.
Furthermore, whilst in all the embodiments
described above the coolant channels extend into and
through the base of the inserts, the invention is equally
applicable to the situation where the coolant channel
extends from the region of the base but not necessarily
through the base. In such embodiments, the coolant
fluid is directed into the coolant channels from externally
located ducts or nozzles.
Whilst in all the embodiments described above the
invention has been applied to replaceable cutting
inserts, it will be understood that the invention is equally
applicable in the case of cutting tools having integrally
formed cutting tips.
Claims
1. A metal cutting tool having a metal cutting tip with at
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least one cutting edge defined between a rake face
and a relief flank (6), characterised in that said relief
flank (6) has a prescribed permissible extent of
flank wear of the cutting edge during use as measured in a direction from said cutting edge and along 5
said relief flank, at least one elongated recess (8) is
formed in said relief flank (6) and constituting a
coolant channel and extending towards said cutting
edge (4) and the upper extremity of said recess is
spaced therefrom by a spacing s which is of the w
order of said prescribed permissible extent of flank
2.
A metal cutting tool according to Claim 1, characterised in that said cutting tip is constituted by a
replaceable cutting insert (3) and furthermore comprises an insert holder (2) for releasably retaining
such insert (3).
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edge (4) wherein d is substantially equal to
10. An insert according to any one of the preceding
claims, characterised in that the total transverse
extent W of the recesses (8) lies substantially within
the range 0.2L to 0.7L, where L is the transverse
extent of the cutting edge (4).
11. An insert according to any one of the preceding
claims, characterised in that recesses (14) are
formed in corners thereof respectively defined by
said relief flank (6) and a pair of adjacent side relief
flanks (13).
12. An insert according to any one of the preceding
claims, characterised in that said relief flank (6) is a
front relief flank.
20 13. An insert according to any one of the preceding
claims and having a plurality of cutting edges
respectively defined between a rake face and a like
plurality of relief flanks, characterised in that in each
of said relief flanks (6, 13) is formed at least one of
said recesses (8, 14).
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3.
A metal cutting tool according to Claim 2, characterised in that said insert holder (2) is formed with a
fluid coolant duct (9) through which coolant fluid
can be directed into said coolant channel.
4.
A metal cutting insert for use in a metal cutting tool
according to Claim 2 or 3, and comprising at least
14. The insert according to claim 4 or any of claims 6 to
one cutting edge defined between a rake face and
13 as dependent on claim 4, wherein said recess
a relief flank, and characterised in that said relief
flank (6) has a prescribed permissible extent of
(8) extends from the region of said base (7) and
flank wear of the cutting edge during use as meas- 30
does not pass therethrough.
ured in a direction from said cutting edge and along
said relief flank, at least one elongated recess (8) is
Patentanspruche
formed in said relief flank (6) and constituting a
1. Metallschneidwerkzeug mit einer Metallschneidcoolant channel and extending from the region of a
base (7) of the insert (3) towards said cutting edge 35
spitze mit mindestens einer Schneidkante, die zwischen einer Spanflache und einer Freiflanke (6)
(4) and the upper extremity of said recess is spaced
therefrom by a spacing s which is of the order of
gebildet ist, dadurch gekennzeichnet, daB die Freisaid prescribed maximum permissible extent of
flanke (6) ein vorgeschriebenes zulassiges Flanflank wear VBmax.
kenverschleiBmaB der Schneidkante wahrend der
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Verwendung bei Messung in einer Richtung von der
An insert according to Claim 4, characterised in that
Schneidkante und an der Freiflanke entlang hat,
said recess (8) extends from and through said base
mindestens eine langliche Aussparung (8) in der
Freiflanke (6) gebildet ist und einen Kiihlmittelkanal
(7).
bildet und zu der Schneidkante (4) verlauft, und das
An insert according to Claim 4 or 5, characterised in 45
obere Ende der Aussparung von ihr urn einen
that said relief flank (6) is bounded on either side
Abstand s beabstandet ist, der in der GroBenordthereof by unrecessed portions (6a and 6b) thereof.
nung des vorgeschriebenen zulassigen FlankenverschleiBmaBes VBmax liegt.
An insert according to any one of the preceding
claims, characterised in that s lies substantially so 2. Metallschneidwerkzeug nach Anspruch 1, dadurch
within the range VBmax to 4VBmax.
gekennzeichnet, daB die Schneidspitze durch
einen austauschbaren Schneideinsatz (3) gebildet
An insert according to Claim 7, characterised in that
ist, und das ferner einen Einsatzhalter (2) zum losbaren Festhalten eines solchen Einsatzes (3) aufs is substantially equal to 1.5VBmax.
weist.
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An insert according to any one of the preceding
3. Metallschneidwerkzeug nach Anspruch 2, dadurch
claims, characterised in that said recess (8) has a
depth d in the region thereof closest to the cutting
gekennzeichnet, daB der Einsatzhalter (2) mit einer
5.
6.
7.
8.
9.
4
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4.
5.
6.
EP 0 534 450 B1
8
Fluidkuhlmittelleitung (9) gebildet ist, durch die ein
Kuhlmittelfluid in den Kuhlmittelkanal geleitet werden kann.
12. Einsatz nach einem der vorhergegangenen
Anspriiche, dadurch gekennzeichnet, daB die Freiflanke (6) eine Vorderfreiflanke ist.
Metallschneideinsatz zur Verwendung in einem 5
Metallschneidwerkzeug nach Anspruch 2 oder 3
und mit mindestens einer Schneidkante, die zwischen einer Spanflache und einer Freiflanke gebildet ist, dadurch gekennzeichnet, daB die Freiflanke
(6) ein vorgeschriebenes zulassiges Flankenver- 10
schleiBmaB der Schneidkante wahrend der Verwendung bei Messung in einer Richtung von der
Schneidkante und an der Freiflanke entlang hat,
und mindestens eine langliche Anssparung (8) in
der Freiflanke (6) gebildet ist und einen Kuhlmittel- 15
kanal bildet und von dem Bereich einer Basis (7)
des Einsatzes (3) zu der Schneidkante (4) verlauft,
und das obere Ende der Aussparung von ihr urn
einen Abstand s beabstandet ist, der in der GroBenordnung des vorgeschriebenen zulassigen 20
FlankenverschleiBmaBes VBmax liegt.
13. Einsatz nach einem der vorhergegangenen
Anspriiche und mit mehreren Schneidkanten, die
jeweils zwischen einer Spanflache und genauso
vielen mehreren Freiflanken gebildet sind, dadurch
gekennzeichnet, daB in jeder der Freiflanken (6, 13)
mindestens eine der Aussparungen (8, 14) gebildet
ist.
Einsatz nach Anspruch 4, dadurch gekennzeichnet,
daB die Aussparung (8) von der Basis (7) und durch
sie hindurch verlauft.
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Einsatz nach Anspruch 4 oder 5, dadurch gekennzeichnet, daB die Freiflanke (6) auf jeder Seite
durch nicht ausgesparte Abschnitte (6a und 6b)
begrenzt ist.
30
7.
Einsatz nach einem der vorhergegangenen
Anspriiche, dadurch gekennzeichnet, daB s im
wesentlichen in dem Bereich von VBmax bis
35
4VBmax liegt.
8.
Einsatz nach Anspruch 7, dadurch gekennzeichnet,
daB s im wesentlichen gleich 1,5VBmax ist.
9.
14. Einsatz nach Anspruch 4 oder den von Anspruch 4
abhangigen Anspriichen 6 bis 13, wobei die Aussparung (8) von dem Bereich der Basis (7) verlauft
und sie nicht durchlauft.
Revendications
1. Outil d'usinage de metal comportant une tete d'usinage de metal avec au moins une arete de coupe
definie entre une face de coupe et un flanc de
depouille (6), caracterise en ce que le flanc de
depouille (6) comporte une quantite permise prescrite d'usure de flanc de I'arete de coupe pendant
son utilisation mesuree dans une direction a partir
de I'arete de coupe et le long du flanc de depouille,
au moins un evidement (8) allonge etant forme
dans le flanc de depouille (6) et constituant un
canal de refrigerant et s'etendant vers I'arete de
coupe (4), et I'extremite superieure de I'evidement
est espacee de celle-ci par un espace s qui est de
I'ordre de la quantite permise prescrite d'usure de
flanc VBmax.
2.
Einsatz nach einem der vorhergegangenen 40
Anspriiche, dadurch gekennzeichnet, daB die Aus3.
sparung (8) eine Tiefe d in ihrem Bereich hat, der
der Schneidkante (4) am nachsten liegt, wobei d im
wesentlichen gleich 2VBmax ist.
45
10. Einsatz nach einem der vorhergegangenen
Anspriiche, dadurch gekennzeichnet, daB die
4.
Gesamtquerausdehnung W der Aussparung (8) im
wesentlichen innerhalb des Bereichs von 0,2L bis
0,7L liegt, wobei L die Querausdehnung der 50
Schneidkante (4) ist.
11. Einsatz nach einem der vorhergegangenen
Anspriiche, dadurch gekennzeichnet, daB Aussparungen (14) in Ecken von ihm gebildet sind, die
jeweils durch die Freiflanke (6) und ein Paar
angrenzende Seitenfreiflanken (13) gebildet sind.
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5
Outil d'usinage de metal selon la revendication 1,
caracterise en ce que la tete d'usinage est constitute par une plaquette d'usinage remplagable (3) et
comprend de plus un support (2) de plaquette pour
tenir de fagon liberable la plaquette (3).
Outil d'usinage selon la revendication 2, caracterise
en ce que le support (2) de plaquette est forme par
un conduit de refrigerant fluide (9) a travers lequel
le fluide refrigerant peut etre dirige dans le canal de
refrigerant.
Plaquette d'usinage de metal destinee a etre utilisee dans un outil d'usinage de metal selon la revendication 2 ou 3, et comprenant au moins une arete
de coupe definie entre une face de coupe et un
flanc de depouille, caracterisee en ce que le flanc
de depouille (6) comporte une quantite permise
prescrite d'usure de flanc de I'arete de coupe pendant son utilisation mesuree dans une direction a
partir de I'arete de coupe et le long du flanc de
depouille, au moins un evidement (8) allonge etant
forme dans le flanc de depouille, (6) et constituant
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EP 0 534 450 B1
un canal de refrigerant et s'etendant a partir de la
zone d'une base (7) de la plaquette (3) vers I'arete
de coupe (4), et I'extremite superieure de I'evidement est espacee de celle-ci par un espace s qui
est de I'ordre de la quantite permise maximale
prescrite d'usure de flanc VBmax.
5.
6.
son avec la revendication 4, dans laquelle
I'evidement (8) s'etend a partir de la zone de la
base (7) et ne passe pas a travers celle-ci.
Plaquette selon la revendication 4, caracterisee en
ce que I'evidement (8) s'etend a partir de la base
(7) et a travers celle-ci.
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Plaquette selon la revendication 4 ou 5, caracterisee en ce que le flanc de depouille (6) est delimite
de chaque cote de celui-ci par des parties non evidees (6a et 6b) de celui-ci.
is
7.
Plaquette selon I'une quelconque des revendications precedentes, caracterisee en ce que s se
trouve sensiblement dans I'intervalle VBmax
20
a4VBmax.
8.
Plaquette selon la revendication 7, caracterisee en
ce que s est sensiblement egal a 1,5VBmax.
9.
Plaquette selon I'une quelconque des revendications precedentes, caracterisee en ce que I'evidement (8) a une profondeur d dans la zone de celuici la plus proche de I'arete de coupe (4) dans
laquelle d est sensiblement egal a 2VBmax.
10. Plaquette selon I'une quelconque des revendications precedentes, caracterisee en ce que I'etendue transversale totale W des I'evidement (8) se
trouve sensiblement dans I'intervalle 0,2L a 0,7L,
dans lequel L est I'etendue transversale de I'arete
de coupe (4).
11. Plaquette selon I'une quelconque des revendications precedentes, caracterisee en ce que des evidements (1 4) sont formes dans des coins de celleci definis respectivement par le flanc de depouille
(6) et une paire de flanes de depouille de cote (13)
adjacents.
12. Plaquette selon I'une quelconque des revendications precedentes, caracterisee en ce que le flanc
de depouille (6) est un flanc de depouille avant.
13. Plaquette selon I'une quelconque des revendications precedentes et comportant une pluralite d'aretes de coupe definies respectivement entre une
face de coupe et une pluralite de flancs de
depouille semblables, caracterisee en ce que dans
chaque flanc de depouille (6,13) au moins un de
ces evidements (8, 14) est forme.
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35
40
45
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14. Plaquette selon la revendication 4 ou I'une quelconque des revendications 6 a 13 prise en combinai-
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