WO2007031252A1 - Cutting insert for a conical milling head - Google Patents

Abstract

A cutting insert (1) for a conical milling head (15) for milling chamfers, in particular for orbital milling of chamfers at pipe ends (25), having a cutting edge (7), which can be exchanged particularly by turning over the cutting insert (1) ("reversible insert"), for milling the bevels (26) with a wedge angle of < 75° between the free face (3) and the cutting face (5) is characterized in that an angled or curved further cutting edge (13), which is produced by an oblique side face (10) which forms an obtuse angle with the free face (3) overall, adjoins one end of the cutting edge (7). The further cutting edge allows a shoulder which adjoins the bevels to be formed at the same time as said bevels. The vertex line (12) of said obtuse angle between the free face (3) and the side face (10, 31) preferably forms a slightly smaller angle (alpha) than 90° with the first cutting edge (7). An adapted support plate (19) which is to be arranged on that side of the cutting insert (1) which is opposite said oblique side face (10; 31) may be associated with said cutting insert.

Description

Description:

Stephan Rieth, D66606 St. Wendel (Germany)

"Cutting plate for a conical milling head"

The invention relates to a cutting insert for a conical milling head for milling bevels, in particular for orbital milling of chamfers at pipe ends, with a, in particular by turning the cutting plate interchangeable ("insert"), cutting edge for milling the bevel with a wedge angle between the free surface and clamping surface 75 °.

Such inserts and milling heads are e.g. from WO 2004/078395 AI and known by use.

The invention has for its object to open further processing options when milling chamfers.

According to the invention, this purpose is fulfilled by the fact that adjoining the one end of the cutting edge an angled or bent further cutting edge, which is generated by a, in total with the open space forming an obtuse angle, oblique side surface.

The further cutting edge has the same rake surface as the former; In other words, it has a continuation of the rake face of the former cutting edge as rake face. Due to the angle formed by the inclined side surface with the free surface, the result is a somewhat duller wedge angle at the further cutting edge than the mentioned wedge angle at the former cutting edge. The additional cutting edge makes it possible to simultaneously mold with the bevel a subsequent paragraph to this. With an angled, straight further cutting edge can be a directly adjoining the slope flat or (at a pipe end) unilaterally curved paragraph train. With a bent further cutting edge, a transition is formed, if necessary, the step is completely curved.

Frequently, the further cutting edge will be angled or bent at an angle from the former cutting edge, in which it lies on the milling head provided for it substantially parallel to the axis thereof. In the case of an axis of the milling head which is aligned parallel to a plane plate to be gripped or parallel to the axis of a tube to be filled, the surface of the shoulder then also becomes parallel to the surface of the plate or of the tube.

In other circumstances, however, it is also possible to orient the milling head axis perpendicular or oblique to the aforementioned orientation in cooperation with the former and the further cutting edge of the cutting tips of the milling head.

Field of application of the cutting insert according to the invention is above all the preparation of weld grooves with comparatively narrow, steep walls and a thin bottom which is intended to melt. Two, as mentioned generated, colliding paragraphs are to form the floor here.

Anyway, for this application, the second cutting edge is shorter than the former. This is probably the most common case, although other proportions are possible.

Preferably, the apex line of said obtuse angle between the flank face and the side face with the former cutting edge forms a slightly smaller angle than 90 °.

Thus, the necessary clearance angle behind the other cutting edge does not have to be created or not only by a tilted arrangement of the cutting plate.

If it is a turning plate on which two oblique side surfaces of the type mentioned opposite each other, while the cutting plate retains a rectangular outline in the median plane, and the two side surfaces twist starting from the end edge lying on the respective rectangle side, so that the two mentioned apex lines are crossed relative to one another.

As a rule, the further cutting edge will adjoin the outer end of the former cutting edge in the arrangement on the milling head.

However, the reverse arrangement is also possible. Then the milling head is to be set differently.

According to a further embodiment of the invention, the cutting plate is one at its said oblique side surface, i. also assigned to the further cutting edge, opposite side to be arranged, adapted support plate.

The support of the force exerted by the further cutting edge on the material by means of this support plate is simpler than the formation of a corresponding seat for the cutting plate on the milling head, i. a seat, which in addition to its the force of the former cutting edge receiving support should also have a force of the further cutting edge receiving second support.

According to a particularly advantageous development of the invention, the cutting insert according to the invention is provided with cutting teeth having saw teeth which are intended for it in such a way that they separate the workpiece following the cutting of the further cutting edges of the cutting plates provided in the plurality on the milling head. This allows a particularly accurate positioning of the heel produced with the further cutting edge at the end edge of the workpiece. At the same time a separate operation for the separation is saved. In the cutting of pieces to be set to pieces of pipe, there is the further advantage of an end edge which lies in a plane which is exactly perpendicular to the tube axis. In this respect, when cutting by means of sawing easily errors with the result that the pipe sections with a slight buckling abut each other.

The drawings represent embodiments of the invention.

1 shows a milling head with inserts according to the invention in front view, FIG. 2 shows the milling head in an isometric view,

3 shows the circled in Fig. 2 section on a larger scale, Fig. 4 shows the milling head from the back in an isometric view, Fig. 5 shows the milling head in side view, but occupied with another

Embodiment of the inserts,

Fig. 6 shows the occupied with inserts according to FIG. 1 to 4 cutting head in the processing of a pipe end in an isometric view and

Fig. 7 shows the circled in Fig. 6 section on a larger scale.

The cutting plate 1 appearing in FIGS. 1 to 3 has the initial shape of a cuboid with a square base. The two broad sides are determined during use as base 2 and support surface 3 and vice versa.

On two opposite narrow sides of the cuboid, two possible clamping surfaces 5 are formed in each case by a symmetrical to the median plane of the cutting insert 1 4 continuous cross-section consistent with a rounded transition 6 between them. Through the cuts of the flat chip surfaces 5 with the free surface 3 and the bearing surface 2, which represents another possible free surface, there are four straight possible cutting edges 7.

One of the broad side to the other continuous central bore has on both sides of a central portion of two seats 8 for a screw head 9.

By turning while maintaining the support surface and the free surface 3 and by turning under exchange of support surface 2 and free surface 3, the four cutting edges 7 can be brought into the working position. The cutting plate 1 is thus a turning plate.

In that regard, the insert is known from WO 2004/078395 Al. According to the present invention, the following further design is provided:

On the two other narrow sides of said cuboid, in contrast to grooves, two outwardly facing oblique side surfaces 10 are formed, again with a transition 10 in the middle. The side surfaces 10 have with the broad sides, ie the support surface 2 and the free surface 3, in each case a common crease line 12. By the sections of the plane possible rake surfaces 5 with the oblique side surfaces 10 results, based on the present example, four straight possible further cutting edges 13. Although identical edges 14 also result at the other end of the cutting edges 7, they can not become cutting edges in the present example. If, according to the abovementioned embodiment, the curve shown in FIG. If the angle alpha is slightly less than 90 °, the angle beta likewise drawn in becomes correspondingly larger and the edge 14 resulting therefrom becomes wholly unsuitable as a cutting edge, ie even under other circumstances. The angle between the cutting edges 7 and the other cutting edges 13 is 120 ° in the present example.

The drawings show a milling head 15 with six seats 16 for an insert 1. The seats 16 each include a seat surface 17 for the support surface 2 of the insert 1, in the seat a threaded hole for a screw

(Screw head 9) for fixing the cutting plate 1 on the seat and an inclined surface 18, where the current rake face 5 on the free surface 2 opposite possible rake face 5 comes to rest and thus the force exerted by the cutting edge 7 force is supported. Due to the conicity of the Fräsköpf the cutting edge 7 is to the axis of the milling head 15 at an angle of 60 °.

Each cutting plate 1 is supported on the milling head 15 by a matched support plate 19. In this case, the adaptation consists of a cross-sectionally dovetail-shaped design of the contact surface 20 that is complementary to the side surfaces 10 of the cutting insert 1.

At the back of the milling head 15 seats 21 are formed for six plate-shaped cutting elements 22. The cutting elements 22 each have three saw teeth 23 which can be selectively brought into a protruding on the periphery of the milling head 15 position. The cutting elements 22 have on the whole the shape of an equilateral triangle and are fixed in the middle with a screw 24 to the milling head 15.

Cut with the mentioned angles, as shown in Fig. 6, the cutting edges 7 at a pipe end 25 at an angle of 60 ° with the tube axis forming bevel 26, the other cutting edges 13 a parallel to the pipe circumference paragraph 27 and the saw teeth 23 a to the Paragraph 27 and the pipe axis perpendicular end edge 28th

The axis of the milling head 15 is always parallel to the tube axis in the circulation around the pipe circumference. In the case of the cutting plates 29 shown in the exemplary embodiment according to FIG. 5, the further cutting edges, designated here by 30, are not angled away from the cutting edges 7, but are bent. The generating oblique side surfaces 31 are correspondingly curved. On the whole, ie apart from the curvature, they form with the free surface 3 as well as an obtuse angle as the oblique side surfaces 10th

When used in accordance with FIG. 6, a rounding occurs between the bevel 26 and the shoulder 27.

In addition, reference is made to WO 2004/078395 A1 for the design of the cutting inserts and their seats, in particular with regard to the wedge angle, rake angle and clearance angle, as well as regrinding.

Claims

claims: 1 . Cutting plate (1; 29) for a conical milling head (15) for milling chamfers, in particular for orbital milling of chamfers on pipe ends (25), with a cutting edge exchangeable, in particular by turning the cutting plate (1; 29), "cutting edge" (7) for milling the bevel (26) with a wedge angle between free face (3) and rake surface (5) <75 °, characterized in that an angled or bent further cutting edge (13 resp 30), which is produced by an oblique side surface (10, 31) which forms an obtuse angle with the free surface (3). 2. Cutting insert according to claim 1, characterized in that the further cutting edge (13; 30) adjoins the arrangement in the milling head (15) outer end of the former cutting edge (7). 3. Cutting insert according to claim 1 or 2, characterized in that the further cutting edge (13; 30) is angled or bent at an angle from the former cutting edge, in which they at the intended milling head (15) substantially parallel to the latter Axis is. 4. Cutting insert according to one of claims 1 to 3, characterized in that the further cutting edge (13; 30) is shorter than the former cutting edge. 5. Cutting insert according to one of claims 1 to 4, characterized in that the apex line (12) of said obtuse angle between the free surface (3) and the side surface (10; 31) with the former cutting edge (7) a slightly smaller angle ( Alpha) as 90 °. 6. Cutting insert according to one of claims 1 to 5, characterized in that it is associated with an adapted seat plate (19) to be arranged on its side opposite to said oblique lateral surface (10; Cutting insert according to one of Claims 2 to 6, characterized in that cutting elements (22) which are to be applied to the milling head (15) and which are provided with saw teeth (23) are associated with them in such a way that, following the cut of the further cutting edge (13 30) of the plurality of cutting heads (15) provided cutting plates (1; 29) the Disconnect workpiece (25).