FR2540762A1 - CUTTING TOOL, AND CUTTING PIECE REPORTED THE CONSTITUENT - Google Patents

Abstract

THE CUTTING TOOL ACCORDING TO THE INVENTION SHOWS IMPROVED EFFICIENCY FOR REMOVING MATERIAL AT RELATIVELY HIGH FEED SPEEDS. IN THE PREFERRED FORM OF A POLYGONAL INSERTED CUTTING PIECE, IT INCLUDES A REINFORCING FLAT 1 ADJACENT TO THE CUTTING EDGES, AND RAMP SURFACES 2A, 3, 5 INTENDED TO COME IN CONTACT WITH THE CHIPS AND CARRIED OUT AT LEAST IN ONE SIDE FROM ABOVE THE REPORTED PART. THE REINFORCEMENT FLAT 1 AND THE RAMP SURFACES 2A, 3, 5 ARE ADVANTAGEALLY DESIGNED TO REDUCE FRICTION AND CUTTING FORCES, TO GIVE EXCELLENT RIGIDITY TO THE CUTTING EDGE AND TO INDUCE FREE CHIP REMOVAL. IN ORDER TO REMEDY THE PREJUDICABLE EFFECT OF THE CONVERGENCE OF THE CHIPS AND TO REMOVE THE HIGH PRESSURES RESULTING FROM THE PRICE NEAR THE TIP RADIUS OF THE CUT CORNER OF THE FITTED PART, A REMOVED CONTROL SURFACE 4 IS POSITIONED IN EACH PARTY CORNER OF THE POLYGONAL FITTED PIECE. APPLICATION TO THE REALIZATION OF USABLE CUTTING TOOLS, IN PARTICULAR, FOR HIGH FEED SPEEDS.

Description

The invention relates generally to cutting tools

  for machining chip forming materials More particularly, the invention relates to

  reported cutting pieces having a geometry of

  control of chip formation particularly advantageous

  at relatively high feed rates.

  Conventional patches with

  There are performance problems with chip control systems when they are used at relatively high feed rates, for example at speeds exceeding 0.5 mm per revolution. These problems are caused by the collision of the chips produced. in the course of the cutting process with one or more front parts of such patches of the state of the art, and the result of these collisions excessive friction and excessive wear, which in turn result in wear and / or premature breakage of the material in which the piece of

reported cut is made.

  Examples of reported cutting inserts having a chip removal control characteristic, and whose geometry results in high chip speeds being achieved at high feed rates.

  under adverse conditions are described in the

  United States of America No 4 288 179, 3 395 434,

3,381,349 and 3,213,716.

  Accordingly, it is an object of this invention to provide a cutting tool for use at relatively high feed rates and having a chip removal control geometry which is

  effective in addressing the problems posed by the

  of the state of the art and presented above.

  In a preferred embodiment, the invention

  tion is in the form of a cutting insert, whose cutting edges can be identified, and intended

  When machining chip-forming materials, the workpiece

  having an improved control characteristic.

  the removal of chips when used for

2 '540762

  Relatively high feed rates A reinforcement plate extends around at least one chip breaker or flank face of the insert and is adjacent to the cutting edges of the insert and to the cutting wedges or dots The first ramp or chip control surface is connected to the reinforcing plate, this first ramp extending

  downward away from the peripheral reinforcement plate.

  The first ramp surface is interrupted at each cut corner of the insert by a tray or corner control surface, to prevent any

  damage to the posterior side of the active cutting wedge

  by the convergence of the chips A second surface of

  ramp or control is adjacent to the first over-

  ramp face and extends downward and inward from the first ramp, preferably with an angle

  tilt lower than that of the first ramp.

  A third ramp surface connects an inner boundary of the corner control surfaces to the second ramp surface,

  at each corner area of the patch.

  The combined boom and control surfaces allow for relatively easy removal of chips at relatively high feed rates, thereby decreasing

  the cutting forces and the corresponding friction.

  The combined geometries of the different parts of the faces of the insert also allow for better control of chip removal at relatively high feed rates, because they cause

  forming chips with convex shaped sections.

  Polygonal patches made

  in accordance with the present invention will have a duration of

  prolonged life because their ability to process chips is

  will be more effective at crater formation and exca-

in the edges.

  Other features and advantages of the invention

  tion will be better understood from reading the description

  will follow several examples of implementation, and referring to

  in the accompanying drawings, in which Figures 1, 2, 3 and 4 show views

  in section of different configurations of the state of technology

  having control characteristics of the removal of

  These configurations are presented by the cut-away or cutting face of known cut-off pieces. FIG. 5 is a perspective view of a workpiece made in accordance with the principles of the present invention. FIG. Section 7 is a sectional view along the line 7-7 of Figure 5. Figure 8 is a cross-sectional view of a first alternative embodiment, Figure 9 is a sectional view along line 7-7 of Figure 5, Figure 8 is a sectional view of a first alternative embodiment. Fig. 10 shows a plan view of a cutting insert made in another form and in accordance with the principles of the invention, and Fig. 11 is a sectional view according to Figs.

line 11-11 of Figure 10.

  In order to highlight the advantages of the invention

  Firstly, reference is made to the various chip control configurations known in the state of the art as shown in FIGS. 1 to 4. Patches of the state of the art, having the geometries controlling the chip removal and shown in Figs. 1, 2 and 4 each depend on shoulders (102 in Fig. 1, 204 in Fig. 2 and 404 in Fig. 4). in order to wind and direct chips produced by the corresponding cutting edges 100, 200, 400 in FIGS. 1, 2 and 4 res

  each of these patches is appro-

  However, such shoulders become detrimental to feed rates producing thick chips. Collision of shavings occurs at relatively low feed rates, for example on the order of about 0.5 mm per revolution or less.

  thicker with these shoulders causes excessive friction

  sif (and as a consequence heat) and excessive wear.

  This excess heat liberated, in turn, causes a chemical reaction between the chips of the machined part and the constituent material of the insert. As a result, such shoulders of chip deflection wear out very quickly, under the -charge conditions imposed by high feed rates, resulting in a longer life

  very diminished useful of the patch.

  The patch of the state of the art shown in FIG. 3 has a cutting edge 300 delimited by the intersection of a flank surface 308 and the reinforcement plate 302, the latter being followed by a sloping surface. 304 and an inner bottom surface 306 which is flat The insert of Fig. 3 is more efficient at higher feed rates, but as the insert must be mounted in a negative attitude (ie that is, with its face 306 shifted upwardly with respect to the ridge 300) to provide clearance on the sidewall between the surface 308 of the insert and the workpiece which is machined, the insert always

  a surface that causes friction and interrupts the removal

chips.

  Another disadvantage related to the use of

  patches with control features of the removes

  The chips produced in accordance with FIGS. 2, 3 and 4 at high feed rates result from the use of a cup-shaped internal recess within the tip radius of the insert. cutting operation of the material, the chip is forced to move down and penetrate in such a recess, while simultaneously seeking to wind on 900 in the direction

  This composite movement of the chip submits the geometry

  edge of the insert providing control of the chip removal at excessive forces caused by attempting to bend simultaneously, in two different directions, a relatively thick chip Such excessive force in the area of peak radius tends

  to fracture the posterior ridge of the tip radius, or to

  excavate this posterior ridge at the active cutting edge of the insert, decreasing

  thus the useful life of the insert.

  A cutting tool according to the invention, such as the cross-piece shown in FIGS. 5 to 7, has a clearance face contour which overcomes the problems presented above and which is found on the inserts of the invention. state of the art when the latter

  are used at relatively high feed rates.

  With reference to FIGS. 5 to 7, the cutting insert 10 has, for example, substantially square top and bottom chipbreaker faces connected by flank walls or sidewalls 7, which are substantially perpendicular to the planes containing the top and bottom faces Four locatable cutting edges are delimited by the intersection of the flank surface 7 with the surface of a reinforcing plate 1 which extends on the periphery of a broken surface as shown on FIG. 6, the angle at 5 between the reinforcing plate 1 and the flank surface

7 is substantially 90.

  A first ramp or control surface, designated 2-a, adjacent to an inner boundary of the reinforcing plate 1, extends downwardly from this boundary forming

  an angle al with the plane of the chipbreaker face This sur-

  ramp or control side 2a extends between the corners of

  cut of the insert, a narrower part 2 prolonged

  part 2 a and extending around each corner of

  rounded cut of the patch.

  A second ramp or control surface 3, adjacent to an inner limit of each ramp surface 2a, extends downwardly from this limit at an angle α 2 with the plane of the broken surface. ramp or control 3 terminates at a bottom surface 6, substantially parallel to the plane of the chipbreaker face The insert 10 can be advantageously clamped in the cutting position-in various known ways

  using the central opening 11.

  At each corner of the room

  reported, the ramp surface 2a is partially interrupted

  stinks by a plateau or corner control surface 4 which is

  which, in this embodiment, is sensitive to

  The internal boundary or edge of each guard surface 4 is, in turn, connected to the control surface 3 via third floor surfaces 5, which extend along the surface of the guard surface 4. to the

  down at an angle to 3 with the plane of the breaker face

  shavings. The width L 1 of the reinforcing plate 1 may range from about 0.38 mm to about 0.89 mm, with a preferred range of about 0.45 mm to about 0, 7 mm, thus giving the corner a mass sufficient to withstand

any deformation.

  The surface 2 and the surface 2a extend downwardly at an angle α within an angular range of from about 100 to about 200, a preferred angular range of about 150 to about 200, in order to achieve

  a regular trajectory opposing any resistance to

  Most of the traps resulting from relatively large cutting depths thus descend along the ramp surface 3 which extends downwardly at an angle α 2 in an angular range from about 50 to about 50.degree. 150, a preferred angular range from about 50 to about 100. Preferably, the angle α1 is larger than the angle α2. With such a configuration,

  surface 3 offers little or no resistance

  to chip removal, unlike the coin

  reported flat bottom shown in Figure 3, and presented

  above-mentioned Even if a wear crater is formed on the surface 3, no adverse effect results therefrom

  affecting the life of the insert, as the

  face 3 is sufficiently spaced inwards relative to

  at the cutting edge of the insert.

  Although the insert shown in FIGS. 5 to 7 must be mounted in a negative draft attitude, the configuration shown allows easy and regular chip removal on the surfaces 1, 2 and 3, with minimal resistance, while allowing the chips to melt and break because of their thickness

  and their own movements The arrangement of the sur-

  faces 1, 2 and 3 thus overcomes the problems of friction

  encountered at the level of the shoulder and the bottom of the

  cutting parts reported from the state of the art.

  This result is obtained by the fact that the chip, after being passed on the reinforcement plate 1, encounters

  surfaces 2 and 3 with a positive orientation (ie

  that is, slope down from the plane of the direction of advance). The innermost limit of surface 2 has

  located at a distance Hi under the plane of the reinforcing plate 1.

  The distance H i lies in a range of values from about 0.10 mm to about 0.25 mm, a range of values

  preferred ranging from about 0.10 mm to about 0.20 mm.

  The innermost limit of the surface 3 is at a distance H 2 below the plane of the reinforcing plate 1 The distance H 2 is in a range of values ranging from about 0.30 mm to a maximum limited depth mainly by the required diameter of the mounting aperture 11, a preferred range of values ranging from about 0.30 mm to about

0.50 mm.

  In order to remedy the problems presented above

  and posed by the convergence of chips, and which result in

  when high pressures develop near the tip radius of the cutting wedge, the guard surface or wedge control surface 4, as well as its connecting ramp surface 5, are placed inside each corner of the wedge The surface 4 extends to a depth H 3 in the plane of the reinforcement plate 1 The depth H 3 is preferably of the order of half the depth Hi The surface 5 extends towards the bottom from an inner boundary of the surface 4, with an angle a 3 lying in a useful angular range from about 10 to about 250,

  a preferred angular range from about 150 to about

  With this configuration, the stresses are reduced in the area of the cutting wedge. Another advantage presented by the corner control surface or the guard surface lies in the ability to ensure good control of the removal of chips for relatively small cutting depths The control surface 4 deflects the

  chips and breaks them when the depth of cut is

  mainly towards the surface 4 Beyond this depth

  cutter, the chips will be removed freely due to the configuration of surfaces 2 and 3 Such free removal of chips, associated with the influence of the surface of

  corner control 4, leads to the formation of a fragile chip

  to a certain extent and barrel-shaped or

  convex, which leads to easier breakage of the chips.

  The dimension L 2 (FIG. 5) is determined by the radius of curvature of the cutting wedge, the dimension L 2 being within the preferred range of values of about one time

  at about one and a half times the value of such a ray.

  Figure 8 shows a variant of configuration

  ration for a reinforcing plate surface 1 'which cuts the

  flank surface 7 at an obtuse angle at 5 '(i.e.

  say that the reinforcing plate 1 'slopes down towards the cutting edge with an angle a 4 relative to

  on the plane of the chipbreaker face) This variant of

  This is beneficial in applications requiring more

  resistance of edges, such as those in which

  the tempered materials are machined. The angle α can be in the angular range from about 900 to about 120, a preferred angular range being

from about 900 to about 100 '.

  FIG. 9 also represents another variant of the embodiment of FIGS. 5 to 7, and in this new variant, each guard surface or wedge control surface 4 'extends downwards at an angle α 6 with respect to FIG. plane of the chipbreaker face The angle a 6 is chosen to be smaller than that of the angle α1 of the first ramp surface 2 (FIG. 7) With a slope directed downwards, the corner control surface 4 may offer less resistance to free chip removal in

  corner-cutting area of there patch.

  A triangular insert made according to

  according to the principles of the invention is shown on

  Figures 10 and 11 This prototype of a triangular patch

  test, tried at relatively high feed rates, greater than 0.5 mm per revolution, has an opening

  conventional assembly 29 and a reinforcement plate 23, of which

  the width is preferably of the order of 0.45 mm, and which

  cuts a flank surface 22 delimiting with this

  an angle of about 900, thereby defining a cutting edge 21. The first ramp surface 24a, 24b extends downwardly from an inner boundary of the reinforcing plate 23, angle of about 150 to an inner limit of about 0.15 mm under the plane of the reinforcement plate 23 The second ramp surface 27 extends downwardly from the inner boundary of the surface 24 a at an angle of about 70 to a bottom surface 28 at a depth of about 0.40 mm under the plane of the reinforcing plate 23 At each corner, a guard surface 25 interrupts the surface 24b at a depth of about 0.07 mm below the plane of the reinforcing plate 23 A third ramp surface 26 extends downwardly at an angle of about 20 to connect the internal boundary of the guard surface 25 at the

ramp surface 27.

  The invention has been described with reference to preferred embodiments by way of example only, and, of course, various modifications may be made by way of example.

  those skilled in the art to the devices which have just been described.

  For example, the different control and ramp surfaces described could be curved rather than flat, provided that the intersections of the different surfaces are tangentially connected in such a way that the formation of any barrier likely to be encountered by chips.

Claims (11)

  1 cutting tool for machining chip-forming materials, and having a cutting wedge defined by the intersection of a broken surface and two flank surfaces (7, 22), characterized by the fact that includes: -   a surface of a reinforcing plate (1, 1 ', 23) extending inwardly from the cutting wedge; = a first control surface (2a, 24A) extending from an inner boundary of the surface of the reinforcement plate (1, 1 ', 23) and downward, with a first angle (a1) relative to in the plane of the chipbreaker surface; a wedge control surface (4, 4 '-, 25) extending inwardly from an inner boundary of the first control surface (2, 24 B);   a second control surface (5, 26) extends   an inner boundary of the corner control surface (4, 4 ', 25) and a second angle (a 3) with respect to said plane; and a third control surface (3, 27) extending from an inner boundary of the second control surface (5, 26) and downwardly with a third angle (a 2) with respect to said plan.   2 cutting tool according to claim 1, characterized in that the surface of the reinforcing plate (1, 1 ', 23) further extends from the cutting wedge and cuts at least one of the flank surfaces. (7, 22) to define a cutting edge (21), the first control surface (2, 24 A) extending further parallel to the cutting edge (21) and being adjacent to an internal limit of the surface of the reinforcing plate (1, 1 ', 23), the third control surface (3, 27) extending further parallel to the cutting edge (21) and being adjacent to an inner boundary of the first control surface (2.24 A), and an intersection of the first and the third control surface (2, 24 A, 3, 27) being interrupted at the cutting corner by   a limit of the second control surface (5,26).   Cutting tool according to claim 2, characterized   characterized in that the wedge control surface (4, 4 ', 25) extends substantially parallel to the plane of the chip breaking surface. 4 cutting tool according to claim 3, characterized in that the surface of the reinforcing plate (1, 1 ', 23) extends substantially parallel to the plane of the chip breaking surface. Cutting tool according to claim 3, characterized in that the surface of the reinforcing plate (1 ') intersects at least one of the flank surfaces (7) at an obtuse angle (at 5 ').   6 cutting tool according to claim 2, characterized   characterized in that the corner control surface (4 ') extends downwardly from a boundary of the first control surface (2, 2 a) at an angle (a 6) to said plane   which is less than the first angle (ai).   An insert insert comprising a polygonal body having opposing top and bottom faces, which extend in substantially parallel planes and a polygonal peripheral surface formed by lateral surfaces (7, 22) substantially perpendicular to the planes and connecting with each other. together at the corners of the polygon cutting, characterized in that at least one of the top and bottom faces comprises: a reinforcing plate (1, 1 ', 23) substantially   plane intersecting each of the side surfaces (7) to delimit   mimic peripheral cutting edges (21) extending between the cutting corners; a first ramp surface (2, 2a, 24A, 24B), substantially planar, extending downward at a first angle (a1) with respect to said planes and from an internal boundary of the reinforcing plate (1, 1 ', 23);   a second ramp surface (3, 27)   planarly extending downwardly at a second angle (a 2) to said planes and from an inner boundary of the first ramp surface (2, 2a, 24A, 24B); substantially planar control surfaces (4,4 ', 25), each positioned at a cutting wedge so as to interrupt a portion (2a, 24A) of the first ramp surface (2 a, 2, 24 A, 24 B); and third substantially planar ramp surfaces (5, 26), each of which connects an inner boundary of a corresponding control surface (4, 4 ', 25) to the second ramp surface (3, 27).   = Z 8 cutting insert according to claim 8, characterized in that the reinforcing plate (1, 23) is   substantially perpendicular to the side surfaces (7, 22).   9 cutting insert according to claim 8, characterized in that the control surfaces (4, 25)   are substantially parallel to said planes.   10 Cutting piece reported according to the claim   9, characterized in that the reinforcing plate (1, 23) extends inwards from the cutting edge (21).   over a distance of the order of 0.38 mm to 0.89 mm -   11 Cutting piece reported according to the claim   9, characterized in that the first ramp surface (2, 24 A) extends downwardly at a first angle (a1) of the order of 100 to 200, to an intersection with the second surface of ramp (3, 27) which is located at a distance of the order of 0.10 mm to 0.25 mm under a plane containing the dish reinforcement (1.23).   12 Cutting piece according to the claim   9, characterized in that the second ramp surface (3, 27) extends downwardly at a second angle (a 2) of the order of 5 to 150 and over a distance of the order of from less   0.30 mm under a plane containing the reinforcement plate (1.23).   13 Cutting piece reported according to the   9, characterized in that the control surfaces (4, 25) each intersect the first ramp surface (2.24 A) at a distance of the order of 0.05 mm to 0.12 mm under a plane   containing the reinforcement plate (1,23).   14 Cutting piece reported according to the claim   9, characterized in that the third ramp surfaces (5, 26) each extend downwardly at an angle (a 3) with respect to said parallel planes of the top faces.   and from below which is of the order of 10 to 25.   Cutting piece reported according to the claim   9, characterized in that the reinforcing plate (1.23) extends inwards from the cutting edge (21) over a distance of the order of 0.45 mm, the first surface ramp (2.24 A) extending downward with a first angle (a1) of the order of 15, to an intersection with the second ramp surface (3.27) which is at a distance of the order of 0.15 mm under a plane containing the reinforcing plate (1.23), the second ramp surface (3.27) extending downwards with a second angle (a 2) of the order 7 to a distance which is of the order of 0.4 mm under the plane containing the reinforcing plate (1.23), the control surfaces (4.25) each intersecting the first ramp surface ( 2.24 A) at a distance of about 0.07 mm under the plane   containing the reinforcement plate (1,23) and the third surface   these ramps (5,26) each extending downwardly at an angle (a 3) of the order of 20 relative to said planes   parallel of the top and bottom faces.