DE3643802A1 - Cutting insert for machining a workpiece - Google Patents

Abstract

A cutting insert with at least one cutting edge (2) for machining a workpiece, in particular for producing a groove-shaped recess, which insert can be inserted into a clamping holder, has, adjacent to the cutting edge (2), a chip-deforming groove (5) which is bounded by side walls (7, 8). Arranged on the side walls, in the region of the cutting edge (4), is in each case one chip face (9, 10) which extends from the cutting edge up to the top edge of the side wall (7, 8). To provide a cutting insert which, in particular when groove cutting, removes comparatively short chips from the workpiece, seen in the feed direction (6) the front part (9), next to the cutting edge (4), of the chip face, and the rear part (10), adjacent to the body (1) of the cutting insert, of the chip face, are arranged at an angle to one another, the chip-face parts bounding an indentation (Fig. 1). <IMAGE>

Description

The invention relates to a cutting insert according to the Preamble of claim 1.

In a known cutting insert of the aforementioned type, the rake face just formed, with a so-called negative angle between the direction of advance of the cutting insert and the rake face are not avoided can be. This results in a relatively high cutting pressure in the area of the rake face and thus high energy consumption. There is also a safe chip break or a safe spiral winding most of the span cannot be reached (DE-OS 30 44 790 and 31 06 120, EP-OS 00 59 602).

A cutting insert is also known which has a straight cutting edge, which is subordinate to a level. This is intended to break the Chips are reached, which rarely leads to the desired success.

The present invention has for its object a cutting insert to create the proportionate especially when grooving short chips from the tool. This task is due to the characteristics solved according to the invention in the characterizing part of claim 1. By the different slopes of the rake face can be in that of the cutting edge  a region of the rake face adjacent to the cutting insert positive cutting angle can be achieved, thereby reducing the cutting pressure good chip formation and thus significantly reduced energy consumption becomes. The chip lifted off the workpiece is in the front area the cutting edge slightly tapered and when striking the invention trained rake face deflected against the cutting direction. In the area the chip deformation groove becomes the chip essentially in the previous direction continued and thereby rejuvenated until it was effective the rake face against the cutting direction because of its spiral shape Training hits the bottom of the groove and breaks.

Further advantages of the invention result from the remaining claims, the description and the drawing. In this is a cutting insert with two cutting edges for machining a workpiece, in particular for producing a groove, as an embodiment of the object the invention is shown schematically. It shows

Fig. 1 is a side view,

Fig. 2 shows a detail from Fig. 1 in a larger scale,

Fig. 3 is a section according to line III-III in Fig. 4,

Fig. 4 is a plan view of the detail according to Fig. 2,

Fig. 5 shows a section according to line VV in Fig. 4,

Fig. 6 is an oblique view of the detail from Fig. 1, also on a larger scale.

The cutting insert according to FIG. 1 has an elongated body 1 which , seen in cross section, is designed in the manner of a hexagon, two perpendicular sides lying opposite one another being substantially longer than the remaining sides. The body 1 is formed from the side in the manner of a rhombus and has a cutting edge 2 or 2 a and an end face 3 or 3 a arranged obliquely to the longitudinal axis on diametrical sides. Since the cutting insert is designed to be center-symmetrical, it is sufficient to describe one of the ends of the cutting insert. The other end is of the same design and may be provided with the same reference numerals to which the letter a is attached. The cutting insert has a cutting phase 4 in the area of the cutting edge 2 ( FIGS. 3 and 4), which extends over its entire width. The cutting phase 4 follows in the direction of the center of the body 1 is a Spanverformungsnut 5 (Fig. 3 and 4), the bottom of which γ of the cutting edge 4 at an angle connects to the dash-dotted feed direction 6 and passes over into a radius R.

On both sides of the chip deformation groove 5 , side walls 7 and 8 are arranged, the upper edges of which are located approximately at the level of the upper side of the rectangle enclosed in the cross section of the body 1 , seen in FIG. 2 below the wedge rising above the cutting edge 2 . The bottom of the chip deformation groove 5 is flat in the transverse direction, the inner surfaces of the side walls 7, 8 each being arranged at an angle ε . The outer sides of the side walls run essentially parallel to the respectively adjacent outer side of the body 1 . The side walls 7 and 8 form a U-shaped edge 11 , seen in plan view ( FIG. 4), which extends around the chip deformation groove 5 and whose width in the area of the chip face 9, 10 is designated by c .

Each of the side walls 7, 8 has in the area of the cutting phase 4 a flat rake face part 9 and an adjoining, likewise flat rake face part 10 . The rake face parts 9, 10 delimit an indentation. The rake face part 9 and the cutting phase 4 run at an angle β to the feed direction 6 and the rake face part 10 runs at an angle δ to the feed direction 6 , a curvature with a radius r being provided at the intersection of the two rake face parts 9 and 10 ( FIG. 2 ). Viewed in the feed direction 6 , the rake surface parts 9, 10 together have the length a and, seen perpendicularly thereto, the height h . Because of the inclined inside of the side walls 7, 8 , the rake surface part 9 is wider than the rake surface part 10 , which tapers towards the center of the body 1 .

The cutting insert can be inserted at an angle λ to the feed direction 6 in a clamp holder, not shown.

Preferred dimensions of the cutting insert are as follows:

l = approx. 31 mm
b = 2 mm to 12 mm
0.7 mm a 2 mm
h : a = 1: 2 to 1: 4, especially 1: 3
R = approx. 6 mm
r 1.5 mm, especially 0.5 mm (as small as possible)
λ = 0 ° to 20 °
β = -3 ° to + 10 °, in particular 0 ° to + 3 °, preferably + 2 °
γ = 10 ° to 30 °, especially 20 °
δ = 20 ° to 60 °, especially 35 °
ε = 15 ° to 45 °, especially 30 °
α = 3 ° to 15 °
s 0.15 mm, in particular 0.05 mm
e = approx. 2 mm, in particular 3.0 mm
c 1 mm, in particular 0.1 mm to 0.2 mm

Here mean:

l = length of the cutting insert b = width of the cutting insert a = length of the rake face in the feed direction h = height of the rake face transverse to the feed direction R = radius of the chip deformation groove 5 r = radius of the curvature between the two rake face parts 9, 10 = setting angle of the cutting insert in the clamp holder = Angle between the direction of advance of the cutting insert and that part 9 of the rake face adjacent to the cutting edge 2 (the angle is positive if it is below the direction of advance 6 as seen in FIG. 2 and negative if it is above it) = angle between the direction of advance of the cutting insert and adjacent the cutting edge side of the Spanverformungsnut w = angle between the feed direction of the cutting insert and the side remote from the cutting edge 2 rake face 10 ε = the angle between the ground and the inner surface of the side wall of the Spanverformungsnut 5 α = angle between the cutting edge 2 adjacent end face of the Cutting insert and the Lotre (this side can be slightly angled in the area of the cutting edge 1 ( FIGS. 2, 3)) s = width of the cutting phase 4 e = length of the chip deformation groove 5 c = width of the edge 11 surrounding the chip deformation groove 5 in the area of the chip face 9, 10

The exemplary embodiment described above has an indented rake face 9, 10 , the rake face parts of which are flat. The rake face parts can each be individually or also jointly, optionally differently curved, wherein a tangential or a bent (indented) transition from one rake face part to the other is provided. The rake face 9, 10 can also be divided into more than two rake face parts, the flat rake face parts also merging into one another with the smallest possible radius.

The chip deformation groove 5 can be divided by at least one part corresponding to the side wall 7, 8 , both sides of this part being arranged at the angle ε .

Instead of an elongated cutting insert according to the embodiment can also be a triangular cutting insert in the form of a Inserts are used whose upper edge is parallel to the Feed direction runs. The aforementioned dimensions apply accordingly.

Claims (8)

1.Cutting insert with at least one cutting edge ( 2 ) for machining a workpiece, in particular for producing a groove-shaped recess, which can be inserted into a clamp holder and which, following the cutting edge ( 2 ), has a chip deformation groove ( 5 ) delimited by side walls ( 7, 8 ) ), whereby a rake face ( 9, 10 ) extending from the cutting edge to the upper edge of the side wall ( 7, 8 ) is arranged on the side walls in the region of the cutting edge ( 4 ), characterized in that the viewed in the feed direction ( 6 ) the cutting edge ( 4 ) adjacent front part ( 9 ) of the rake face and the rear part ( 10 ) of the rake face adjacent to the body ( 1 ) of the cutting insert are arranged at an angle to one another, the rake face parts delimiting an indentation. 2. Cutting insert according to claim 1, characterized in that the front part and the rear part of the rake face ( 9, 10 ) are each flat and merge into one another in a curvature with a relatively small radius (r) . 3. Cutting insert according to claim 1, characterized in that the front part and the rear part of the rake face ( 9, 10 ) are each uniformly curved and merge tangentially. 4. Cutting insert according to claim 1, characterized in that the rake face ( 9, 10 ) is divided into more than two different pitch angles having flat partial surfaces, each merging into a curvature with a relatively small radius. 5. Cutting insert according to claim 1, characterized in that one part of the rake face is arched and the other part of the Rake face is flat and that the flat part according to Art a tangent merges into the curved part. 6. Cutting insert according to claim 1, characterized in that one part of the rake face is arched and the other part of the Rake face is flat and that the two parts with one Curvature merge, the radius of which is smaller than the radius of the curved part of the rake face. 7. Cutting insert according to one of the preceding claims, characterized in that the front part ( 9 ) of the rake face with respect to the feed direction ( 6 ) has an angle β which is in the range between -3 ° and + 10 °, in particular + 2 ° , wherein the angle below the feed direction is denoted by "+" and that the rear part ( 10 ) of the rake face has an angle δ with respect to the feed direction which is 20 ° to 60 °, in particular 35 °. 8. Cutting insert according to one of the preceding claims, characterized in that measured in the longitudinal direction of the cutting insert, the length a of the rake face ( 9, 10 ) is in the range between 0.7 mm to 2 mm, and that the ratio of perpendicular to the feed direction ( 6 ) measured height (h) of the rake face to length 1: 2 to 1: 4, in particular 1: 3.