WO2005118187A1

WO2005118187A1 - Indexable insert for iso tool holder

Info

Publication number: WO2005118187A1
Application number: PCT/AT2005/000186
Authority: WO
Inventors: Armin Schlemmer; Walter Bärnthaler
Original assignee: Boehlerit Gmbh & Co.Kg.
Priority date: 2004-06-02
Filing date: 2005-05-31
Publication date: 2005-12-15
Also published as: AT500864A1; AT500864B1

Abstract

The invention relates to an indexable insert (1) to be fastened in a tool holder (K) having a geometrical shape according to DIN 4984 ISO designation system: P - type of fixation: P or M, N - insert clearance angle: N (0°). The aim of the invention is to provide an indexable insert which allows to machine work pieces with lower roughness of the surface produced and/or at increased cutting rate. For this purpose, at least one of the parallel supports (11, 11°) of the indexable insert (1) comprises one or more planar surface sections (111, 112) projecting from the surface (2, 2°) to the same extent. Lateral surfaces (3, 3', 3', 3''') are configured at a right angle to this/these surface section(s) and define cutting edges (4, 4', 4', 4''', 4°) with the faces or chip grooves (21) of the surfaces (2, 2'), whereby said lateral faces produce corners (5, 5', 5', 5'''). When seen from a top view, the areas (B) of the cutting edges (4', 4''') close to the corners have a convex shape. When seen from the indexable insert, each cutting edge (4', 4°), at least in the convex area (B), slopes away from the corner (5', 5''') in relation to the support (11, 11°).

Description

Indexable insert for ISO toolholders

The invention relates to an indexable insert for fastening in a tool holder with a geometric shape in accordance with DIN 4984 ISO designation system: P - fastening type: P or M N - insert angle: N (0 °)

In the modern machining technology of workpieces, the cutting tools are standardized in their geometrical form, in order to indicate favorable machining conditions on the one hand and to be able to achieve correspondingly high machining efficiency on the other. On the basis of the requirements placed on the machined workpiece, in particular on its surface quality, the skilled person selects the tools with a corresponding cutting edge geometry for economical production.

In principle, an increase in chip removal is possible to increase the cost-effectiveness of surface processing, especially with rough turning according to DIN 8689. This can be done at the same cutting speed by a comparatively higher depth of cut or by increasing the tool feed. Because an increase in the depth of cut is usually not cheap or has a negative effect on the tool life, attempts are usually made to increase the stock removal rate by increasing the tool feed.

However, increasing the stock removal rate for a workpiece by increasing the tool feed is associated with disadvantages when using indexable inserts with a clearance angle of 0 ° in a clamp holder provided for this purpose. On the one hand, an enlarged feed causes a substantially increased roughness of the machined surface on the workpiece with so-called spiral grooves, on the other hand, essentially due to the required inclined support prismatic indexable insert in the clamp holder to obtain a clearance angle of 6 ° at the cutting edge corner with the distance from it an increase in the cutting edge relative to the workpiece axis, so that with increased feed and thereby an extension of the cutting edge in engagement, the locally given clearance angle in the cutting edge area is reduced to a great disadvantage is.

The aim of the invention is to overcome the disadvantages in the prior art and to create an indexable insert with a clearance angle of 0 °, which can be fixed in an ISO clamp holder provided for this purpose, and such a machining, in particular rough machining, of workpieces with less roughness and / or increased stock removal.

This goal is achieved with an indexable insert of the type mentioned in the introduction, in which, according to the invention, one of the mutually parallel supports of the

Indexable insert consists of one or more, preferably eight, flat surface parts protruding from the surface at the same level and to this (these) perpendicularly, with the rake faces or chip recesses of the surfaces producing cutting edges, side faces which are shaped with one another, optionally rounded, Form corners, the planes near the corners of the cutting edges have a convex shape and in the view of the indexable insert from the corner, at least in the convexly shaped area, the cutting edge is formed sloping with respect to the contact surface.

The advantages achieved with the invention essentially consist in that, compared to an indexable insert according to the prior art, the new cutting geometry enables machining with approximately the same roughness or quality of the machined surface, but with a feed rate that is approximately twice as high a significantly smoother or a significantly improved surface quality can be produced with the same feed.

At this point, it should be noted as a precaution that, according to the ISO designation system (Tab. 1), attachment type P is an indexable insert with an An essentially prismatic shape can be clamped from above and / or through a bore (designation M), it also being possible to use indexable inserts without a hollow in the sense of the invention.

A prismatic shape of an indexable insert has the advantage that the cutting edges of the top and those of the bottom can be inserted away from the respective cutting corner and double the number of cutting zones are available per cutting insert. However, what is provided in the standardization, the clamp holders must have an inclined insert support to ensure a required clearance angle of more than 3 °, in particular of approximately 6 ° and higher.

Such indexable inserts can advantageously have chip troughs if surface parts which form a support surface are protruding from the surface to an identical level.

For an improved function of the cutting insert according to the invention in a standardized clamp holder with an inclined seating position for the insert, it is important that the areas of the cutting edge near the corner which are effective for chip removal with high feed are made convex and essentially axially parallel to the workpiece.

According to specialist opinion, an acute angle is required for the cutting edge away from the cutting corner opposite the workpiece axis of rotation or perpendicular to the feed in order to ensure that the tool is released. Contrary to this expert opinion, it was found that with indexable inserts, which have a convex cutting edge shape in the plan view in the area near the corner, in which view the cutting edge is formed sloping towards the contact surface, installed in an ISO toolholder, an increased stock removal rate and / or a significantly improved surface quality of the machined workpiece can be achieved.

The cutting tip according to the invention advantageously has a rounded top view Corners, the area of the cutting edges close to the corner having a convex shape. In this way, the cutting edge retention of the insert and the stock removal process can be further improved.

A particularly preferred embodiment of the invention can be achieved with an indexable insert according to the invention in which the top view of the cutting edge has a parallelogram shape and in each case an acute-angled corner has an angle of 55 ° to 85 ° and / or a radius of 0.4 mm to 4.0 mm, preferably has an angle of 75 ° to 85 ° and / or a radius of 0.5 mm to 1.0 mm.

For high-performance machining of tough and tough steel, tested and tested in test series and in production, an indexable insert in which the convex area following the rounding of the corners has an extent of at least that value of the radius of the "corner rounding, but is less than that of the longitudinal extent of a side surface broken by 2.5, particularly good results, both in terms of minimizing the roughness depth of the machined surface and the economy of the machining.

An indexable insert according to the invention, in which, in the view, the cutting edge falls away from the right-angled or acute-angled corner, based on the contact surface, has an angle of at least 4 ° and at most 8 ° and in particular is essentially equal to the angular deviation between the workpiece axis (A) and Clamp holder contact surface is formed in the direction parallel to the axis, can preferably be used universally for turning different iron-based alloys.

Especially for a, according to ISO designation system, clamp holder form L has an indexable insert with a form C, in which the drop of the cutting edges from the acute-angled corner, based on the contact surface, has an angle of 6.6 ° to 7.6 ° and the same angle at the obtuse-angled corner of the indexable insert is 4.1 ° to 5.1 °, outstanding high-performance machining results with high surface quality. In the following the invention is based on a table and only one

Execution path illustrating drawings explained in more detail.

It shows

Tab. 1: ISO designation system for toolholders, external machining (DIN 4984)

Fig. 1: Indexable insert according to the invention in plan view

Fig. 2: indexable insert according to Fig. 1 in view

Fig. 3: corner formation (detail of Fig. 1)

Fig. 4: Indexable insert in the clamp holder (top view)

Fig. 5: Indexable insert in the clamp holder (view)

Fig. 6: Indexable insert in the clamp holder (front view)

Fig. 7: Indexable insert in the holder (front view) for left-hand feed Fig. 8: Insert in the holder (front view) for right-hand feed

As an alternative, a list of reference symbols is inserted below for the details shown in the figures.

Indexable insert 1 support 11.11 ° support surface parts 111.112 surface 2.2 ° chip recess 21 side surfaces S ^ S "^ '" cutting edge 4.4' _f 4 ^» _> 4"^«; 4 ° '(Rg.2) corner OO, o, corner area E convex area B radius of the corner R longitudinal extension L workpiece axis A clamp holder K Table 1 shows the ISO designation system for toolholders for external machining. An indexable insert according to the invention has a clearance angle of 0 ° (Table 1, row N, position N) and is provided for a type of clamp holder (row P, position M or P) clamped from above and / or via a bore.

1 shows a plan view of an indexable insert 1 according to the invention for clamping by means of a bore and with four corners. This plate is essentially prismatic with four side surfaces Z, 3 3 ", 3 ^W , has two acute-angled corners 5 ', 5'" and has a length L. according to the invention in corner region E are described in more detail.

The indexable insert 1 has a surface 2 with projecting therefrom and a plane 11 forming support-surface portions 111,112 at which plane 11 side faces ^3,3,, 3 "3 ^m at a right angle is formed. One of the surface 2 opposing support surface 2 ° can be flat or preferably have the same structure with a plane-parallel support plane 11 °.

The side surfaces 3, 3 ^H _t 3 ^m and the rake surface or chip recess 21 of the surface 2 form cutting edges 4, 4 ', 4 ", 4" ^, _f which have a convex shape in a plan view from a corner 5' in the region B , This convex shape of the cutting edges

4 ', 4 "can be created by rounding or by means of a succession of flat parts of the side faces 3,3" in the area B near the corner.

Fig. 2 shows the insert 1 acc. Fig. 1 in view. A cutting edge 4 ¹ formed with a side surface 3 runs away from an acute-angled corner 5 'of the cutting plate 1, falling away from the support 11 of the surface 2, at an angle β. This falling of the cutting edge 4 ′, 4 ″ is advantageously the same at least in the convex region B at a corner 5 ′, after which there is subsequently an increase in the edge with a smaller angle to the obtuse-angled corner 5.

An indexable insert 1 according to the invention can have two identical shapes have opposite surfaces 2.2 °, which doubles the number of cutting areas.

FIG. 3 shows a corner region E of an acute-angled corner 5 of an indexable insert 1 according to FIG. 1. This corner 5 "is rounded with a radius R. As a result, the area B is reduced to a convex area B 'of the cutting edges 4', 4" adjoining a corner rounding R.

4 shows a clamp holder K (ISO designation system, type of fastening M or P) with an indexable insert 1 in a top view.

FIGS. 5 and 6 show the positioning of the essentially prismatic indexable insert 1 in the ISO clamp holder K in a view with the detail X or in an end view with the detail Y in a required or standardized inclined position for machining.

7, which illustrates the detail X from FIG. 5, provides an enlarged view of an indexable insert 1 according to the invention, fixed in an ISO clamp holder K. An inclined position at an angle e of the plate provided with essentially plane-parallel contact surfaces with respect to a workpiece -A axis of rotation can be seen. With respect to this axis A, however, the cutting edge 4 of the indexable insert lies in a plane with the axis A due to a drop in the convex region B of the side face 3, although the support 11 ° forms an angle ^ to this.

FIG. 8 shows an enlarged detail Y of FIG. 6 with the cutting edge 4 shaped according to the invention in the convex region B of the side surface 3. ISO designation system ^for tool holder, external machining IS e ^ αnat> nn w ≠ em ^{for too! ho, the $} ' ^{externaI machInϊn9}

N Insert clearence angle

Clearance angles where special information is required. Cfearance angle requiring special indication

Claims

claims

1. Indexable insert (1) for fastening in a clamp holder (K) with a geometric shape in accordance with DIN 4984 ISO designation system: P - Type of fastening: P or M N - Insert angle: N (0 °)

wherein at least one of the mutually parallel supports (11.11 °) of the indexable insert (1) consists of one or more, preferably eight, flat surface part (s) (111.112) projecting from the surface (2.2 °) to the same level and perpendicular to this (those) with the clamping surfaces or the clamping troughs (21) of the surfaces (2,2 °) cutting edges ^(4.4,, ^,, 4, 4 ^'; 4 °) generating, side surfaces ^(3.3, 3 ", 3"'are formed) connected together, optionally rounded corners (5 _f ^5, 5 ^,, _I 5 "'), wherein in plan view the corner regions near (B) of the cutting edges ^(4.4,, 4 ", 4 '") have a convex shape and in the view of the indexable insert in each case away from the corner (δ'.δ'") at least in the convexly shaped area (B) the cutting edge (4 \ 4 ^β ') falls off with respect to the support plane (11.11 °) is formed.

2. Indexable insert according to claim 1 with rounded corners in plan view, wherein the region (B) of the cutting edges (4 \ 4 ") adjacent to the corner (R) has a convex shape.

3. indexable insert (1) according to claim 1 or 2, wherein in plan view the cutting edge ^(4, 4 ") has a parallelogram shape and each having a acute angle shaped corner (δ'.S"') forms an angle of 55 ° to 85 ° and / or has a radius (R) of 0.4 mm to 4.0 mm, preferably an angle of 75 ° to 85 ° and / or a radius (R) of 0.5 mm to 1.0 mm.

4. indexable insert (1) according to one of claims 1 to 3, in which each of the rounding (R) of the corners (5) adjoining convex region (B ') has an extent of at least that value of the radius (R) of the corner rounding , but is less than that of the longitudinal extension (L) one Side area broken by 2.5.

5. indexable insert (1) according to one of claims 1 to 4, in which in the view of the drop of the cutting edge (4) from the right-angled or acute-angled corner (5), based on the bearing surface (11, 11 ") an angle 3 of at least 4 °, and at most 8 °, and in particular is essentially the same as the angular deviation & t between the workpiece axis (A) and the clamp holder support surface in the direction parallel to the axis.

6. indexable insert (1) according to one of claims 1 to 5, wherein the drop of the cutting edges (4,4 ') from the acute-angled corner (δ'.δ' "), based on the contact surface (11,11 ') has an angle β of 6.6 ° to 7.6 ° and the similar angle at the obtuse-angled corner (δ, δ ") of the indexable insert (1) is 4.1 ° to δ, 1 °.