Tool for chip removing maching

A tool for chip removing machining comprising a tool head, which is provided with insert seats for the receipt of replaceable cutting inserts as well as a fastening part intended to be received in a machine tool. The tool has at least two chip pockets, in each one of which two replaceable cutting inserts are arranged, the two cutting inserts arranged in each chip pocket being intended for different types of machining and having the active surfaces thereof opposite each other. Furthermore, the two cutting inserts arranged in a common chip pocket have their axially furthermost portions located at different levels in the axial direction of the tool. The two cutting inserts for turning are located in different chip pockets and have their axially furthermost portions thereof located at different levels in the axial direction.

CROSS REFERENCE TO RELATED APPLICATION

BACKGROUND OF THE INVENTION

The present invention relates to a tool for chip removing machining, comprising a tool head, which is provided with insert seats for the receipt of replaceable cutting inserts as well as a fastening part, which is intended to be received in a machine tool, and having at least two chip pockets, in which two replaceable cutting inserts are arranged. The cutting inserts are intended for different types of machining and have active surfaces thereof opposite each other. Two cutting inserts arranged in a chip pocket have axially foremost portions thereof situated at different levels in the axial direction. The tool according to the present invention is preferably intended for machining of metal.

DE 37 33 298 C2 discloses a combination tool for chip removing machining, which, according to one embodiment, has two indexable inserts in the same chip pocket, the cutting inserts being spaced-apart in the circumferential direction of the tool. One of the cutting inserts is a center cutting insert and the other one is a peripheral cutting insert. By means of the combination tool, different types of chip removing machining can be carried out, for instance turning, milling and drilling.

EP 1 186 367 A1 discloses a tool by means of which turning and milling can be carried out. There is no clear division of which type of machining the cutting inserts of the tool should carry out. For instance, the same cutting inserts are used both for milling and for turning. Furthermore, both of the cutting inserts arranged in a chip pocket are used for turning.

WO 2004/069455 A1 discloses a tool for chip removing machining, which comprises a tool head, which is provided with insert seats for receiving replaceable cutting inserts. The tool head has at least one chip pocket, in which two replaceable cutting inserts are arranged, the cutting inserts being intended for different types of machining and having the active surfaces thereof opposite each other. The cutting inserts included in one and the same chip pocket are of different types, more precisely, one of the cutting inserts is intended for rotary machining while the other one is intended for turning.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a tool for chip removing machining where the cutting inserts are arranged in such a way that they should not interfere with each other when different types of machining are carried out.

Another object of the present invention is that the tool should be exceptionally simple to use by the fact that standard settings of the tool in relation to the workpiece apply to most working operations.

Still another object of the present invention is that the tool should be provided with cutting inserts of standard design.

According to an aspect of the present invention, a tool for chip removing machining, comprises a tool head including insert seats for receipt of replaceable cutting inserts. A fastening part is received in a machine tool. At least two chip pockets are provided, each of the chip pockets including cutting inserts intended for different types of machining and having active surfaces thereof opposite each other. The cutting inserts are arranged in a common chip pocket and have axially furthermost portions located at different levels in an axial direction of the tool. The cutting inserts for turning being located in different chip pockets and have axially furthermost portions located at different levels in the axial direction of the tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The tool shown inFIGS. 1 and 2comprises a tool head1, a shaft3as well as a fastening part5, which is intended to be received in a machine tool. At the free end thereof, the fastening part5may be provided with a coupling, for instance of the type that is marketed under the trademark COROMANT CAPTO®. A center axis of the tool is designated C1-C1. This axis is also the axis of rotation and defines the axial extension of the tool. The tool head1defines a front end of the tool, while the fastening part5defines a rear end of the tool.

The tool head1of the shown embodiment of the tool comprises two chip pockets7and9, respectively, two cutting inserts for chip removing machining being received in each chip pocket7,9. More precisely, each individual insert is mounted in a seat (having no reference numeral) formed in the surfaces confining each pocket, the insert being fixed by means of a screw. In a first chip pocket7, a first milling insert10as well as a first turning insert11are mounted. These cutting inserts10,11have their active surfaces opposite each other. In the second chip pocket9, a second milling insert12as well as a second turning insert13are accomodated. Also these cutting inserts12,13have their active surfaces opposite each other. For all these cutting inserts10-13applies that they, in the embodiment illustrated, are fixed in their respective seats by means of locking screws. Preferably, the milling inserts10and12are identical and are end mill inserts. The milling inserts10and12have respective major cutting edges10aand12awhich are situated in a common, imaginary cylindrical surface having the center axis thereof coinciding with the center axis C1-C1of the tool. The wiper edges10band12bof the respective milling insert10and12lie in a common, imaginary plane that is perpendicular to the center axis C1-C1of the tool.

FromFIG. 3, it is seen that the portions of the two milling inserts10and12located furthest forward in the axial direction (C1-C1) are situated on the same axial level and that the portions are situated further forward in the axial direction (C1-C1) of the tool than the portions of the turning inserts11and13located furthest forward in the axial direction. In this connection, the furthermost portion of the first turning insert11is located at a distance δ1 behind the furthermost portion of the milling inserts10and12, while the furthermost portion of the second turning insert13is located at a distance δ2 behind the furthermost portions of the milling inserts10and12. An important feature of the tool according to the present invention is that to δ1<δ2. The significance of this relation between δ1 and δ2 will be explained more thoroughly below.

From the end view shown inFIG. 4, it is seen that the dash-dotted reference circle RC defined by the portions of the milling inserts10and12located farthest out in the radial direction is situated outside the portions of the turning inserts11and13located farthest out in the radial direction.

Thus, since the axially furthermost portions of the milling inserts10,12lie axially in front of the axially furthermost portions of the turning inserts11,131, and since furthermore the radially furthermost portions of the milling inserts10,12lie radially outside the radially furthermost portions of the turning inserts11,13, the tool according to the present invention may be used for milling without interference of the turning inserts11,13.

FromFIG. 4, it is further seen that the cutting tips14,15of the turning inserts11and13, respectively, are located along a line L1through the center of the tool. This simplifies the programming of the multi-function machines in which the tool is aimed to be used.

Below, a number of working operations that can be carried out by means of the tool will be illustrated. In this connection, the tool machines a workpiece A, which has a center or rotation axis C2-C2. In general, it could be said that, in the shown working operations, the center axis C1-C1of the tool either forms a right angle with the center axis C2-C2of the workpiece, or the center axis C1-C1of the tool is parallel to the center axis C2-C2of the workpiece.

The working operation shown inFIGS. 5 and 6illustrates longitudinal turning of the workpiece A. In spite of the milling inserts10,12being situated axially in front of the turning inserts11,13, it is seen fromFIG. 5that the milling inserts10,12do not interfere with the workpiece A in this working operation. The reason therefor is that the external contour of the workpiece A has a certain curvature. FromFIG. 6, it is seen that the first turning insert11is in engagement with the workpiece A, while the second turning insert13is situated axially behind the first turning insert11, i.e., the second turning insert13is situated at a certain distance from the workpiece A. This positioning of the turning inserts11and13is a result of the fact that δ1<δ2. For exemplifying, but not limiting purposes, it may be mentioned that δ1 may be in the interval of 0.2-1.0 mm, preferably 0.3-0.5 mm, while δ2 may be in the interval of 0.4-2.0 mm, preferably 0.6-1.0 mm. Even if the given intervals partly overlap each other, the relation δ1<δ2 generally applies. For the working operation shown inFIGS. 5 and 6applies that C1-C1is perpendicular to C2-C2.

As for the orientation of the first turning insert11in the tool, reference is made to a first bisector B1, seeFIG. 3, which traverses the insert tip of the first turning insert11and halves the first tip angle α1. The first bisector B1forms a first obtuse angle β1with the center axis C1-C1of the tool. For exemplifying, but not limiting purposes, it may be mentioned that if the first tip angle α1=80°, a suitable value of the first obtuse angle is β1=135°. The first tip angle α1is suitably in the interval of 75°<α1<90°. When α1is within the interval of 75°<α1<90°, the value of the first obtuse angle β1normally varying ±5°. The value of the first obtuse angle β1is determined by considerations regarding the clearance of the first turning insert11in relation to the workpiece A.

As for the orientation of the second turning insert13in the tool, reference is made to a second bisector B2, seeFIG. 6, which traverses the insert tip of the second turning insert13and halves the second tip angle α2. The second bisector B2forms a second obtuse angle β2with the center axis C1-C1of the tool. It may be mentioned that if the second tip angle α2=55°, a suitable value of β2=120°. If the second tip angle α2=35°, a suitable value of β2=110°. Generally, the equation 2α2<β2should apply. The value of the second obtuse angle β2is above all determined by considerations as for the pressing of the second turning insert13against the workpiece A in the turning operation shown inFIG. 8.

FIG. 7schematically illustrates two turning operations using the first turning insert11, which is an insert carrying out so-called roughing. In this context a longitudinal, external turning with the center axis C1-C1of the tool forming a right angle with the center axis C2-C2of the workpiece, as well a turning of an end surface of the workpiece A are illustrated, also here the center axis C1-C1of the tool forming a right angle with the center axis C2-C2of the workpiece A. Thus, between the turning operations illustrated inFIG. 7, only a parallel displacement of the tool takes place.

InFIG. 8, a turning operation using the second turning insert13, i.e., the cutting insert carrying out so-called finishing, is schematically shown. In this connection, longitudinal, external turning with the center axis C1-C1of the tool being parallel to the center axis C2-C2of the workpiece is illustrated.

InFIG. 9, it is schematically shown how an axial hole in the workpiece A is provided by means of milling in the form of helical interpolation, the two milling inserts10and12of the tool carrying out the working operation. Here, the center axis C1-C1of the tool is parallel to the center axis C2-C2of the workpiece A.

InFIG. 10, internal turning of the hole milled inFIG. 9is schematically shown. This internal turning is carried out using the second turning insert13, which is an insert performing so-called finishing. Here, the center axis C1-C1of the tool is parallel to the center axis C2-C2of the workpiece A.

FIGS. 11 and 12schematically show how a planar surface of the workpiece A can be produced by two different milling operations by means of the tool. InFIG. 11, the center axis C1-C1of the tool is oriented perpendicularly to the center axis C2-C2of the workpiece A, while inFIG. 12the center axis C1-C1of the tool is parallel to the center axis C2-C2of the workpiece A.

In the embodiment of the present invention described above, the tool is provided with a certain set of cutting inserts for chip removing machining. As for the turning inserts in particular, these inserts may be of another type than the ones described above. Such turning inserts should, however, be intended for different kinds of machining for the relation δ1<δ2to be of relevance.

In the embodiment described above, it has been stated that the cutting inserts are fixed in their seats by means of locking screws. Within the scope of the present invention it is, however, also conceivable to fix the cutting inserts in alternative ways, e.g. by means of a top clamp or the like.

In the working operations shown above and carried out by means of the tool according to the present invention, the center axis C1-C1of the tool assumes a position being either perpendicular to or parallel to the center axis C2-C2of the workpiece A. This is the preferred way to use the tool, but it should be pointed out that the tool can also be used when the center axis C1-C1of the tool forms, for instance, an acute angle with the center axis C2-C2of the workpiece A.