EP1737597A1 - Cutting insert having a limited number of frame faces - Google Patents

Cutting insert having a limited number of frame faces

Info

Publication number
EP1737597A1
EP1737597A1 EP05732915A EP05732915A EP1737597A1 EP 1737597 A1 EP1737597 A1 EP 1737597A1 EP 05732915 A EP05732915 A EP 05732915A EP 05732915 A EP05732915 A EP 05732915A EP 1737597 A1 EP1737597 A1 EP 1737597A1
Authority
EP
European Patent Office
Prior art keywords
faces
lateral
framing
housing
anterior
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05732915A
Other languages
German (de)
French (fr)
Inventor
Richard Fouquer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Safety SAS
Original Assignee
Safety Production SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Safety Production SAS filed Critical Safety Production SAS
Publication of EP1737597A1 publication Critical patent/EP1737597A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B51/00—Tools for drilling machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C5/00—Milling-cutters
    • B23C5/16—Milling-cutters characterised by physical features other than shape
    • B23C5/20—Milling-cutters characterised by physical features other than shape with removable cutter bits or teeth or cutting inserts
    • B23C5/22—Securing arrangements for bits or teeth or cutting inserts
    • B23C5/2204—Securing arrangements for bits or teeth or cutting inserts with cutting inserts clamped against the walls of the recess in the cutter body by a clamping member acting upon the wall of a hole in the insert
    • B23C5/2208—Securing arrangements for bits or teeth or cutting inserts with cutting inserts clamped against the walls of the recess in the cutter body by a clamping member acting upon the wall of a hole in the insert for plate-like cutting inserts 
    • B23C5/2213—Securing arrangements for bits or teeth or cutting inserts with cutting inserts clamped against the walls of the recess in the cutter body by a clamping member acting upon the wall of a hole in the insert for plate-like cutting inserts  having a special shape
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C2200/00—Details of milling cutting inserts
    • B23C2200/12—Side or flank surfaces
    • B23C2200/125—Side or flank surfaces discontinuous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C2210/00—Details of milling cutters
    • B23C2210/16—Fixation of inserts or cutting bits in the tool
    • B23C2210/168—Seats for cutting inserts, supports for replacable cutting bits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T407/00—Cutters, for shaping
    • Y10T407/19—Rotary cutting tool
    • Y10T407/1906—Rotary cutting tool including holder [i.e., head] having seat for inserted tool
    • Y10T407/1908—Face or end mill
    • Y10T407/1924—Specified tool shape
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T407/00—Cutters, for shaping
    • Y10T407/23—Cutters, for shaping including tool having plural alternatively usable cutting edges

Definitions

  • the present invention relates to the clamping of removable cutting chips on a tool holder, such as for example a drill.
  • a removable cutting insert is pressed against the bottom of a tool holder housing by a clamping screw freely passing through a central hole in the cutting insert to engage a tapped hole in the bottom of the housing .
  • this play is found as uncertainty in the framing of the cutting insert on this bottom.
  • the workpiece and vibrations are likely to apply a torque to the wafer around the clamping screw.
  • the housing has a flat side wall, and even in general two, respectively longitudinal and axial with respect to a general axis of the tool holder, serving to support the corresponding flat side faces of the insert, to form, with the bottom, a trihedron for receiving a corner of the plate, thus blocked in translation and in rotation.
  • the wafer therefore has generally two large rectangular parallel faces, front and rear, connected by four side s' anes faces defining four straight edges with large front surface, two successive lateral faces serving as a support of framing, the other two side faces can perform this function if the plate is reversible.
  • the housing is open axially at the end and / or laterally to leave one of the above edges accessible, as a cutting edge.
  • the cutting edges must, however, for certain applications, have, in plan view, an angular profile, that is to say that one side of the classic rectangle delimiting the large anterior face is then replaced by two successive segments.
  • the cutting edge comprises an end section in bevel or cutaway, folded towards the next edge.
  • the cutting edge on the opposite side therefore has the same angular shape.
  • this shape is determined by the intersection between the large anterior face and the respective lateral support face, each of the lateral support faces must therefore in principle be provided in the form of two mutually inclined flat zones, in plan view of the brochure.
  • the classic rectangle limiting the large front face is replaced by a hexagon and this hexagonal shape applies to all the sections parallel to the large faces, that is to say for the framing support flanks.
  • the periphery of the receiving trihedron of the wafer initially defined by two perpendicular side walls representing half of the periphery of the wafer, is now defined by four side surfaces which, admittedly, always represent half of this periphery, but now limit the periphery of the bottom of the housing according to a less angular shape, that is to say with sections or facets of generally rounded appearance.
  • the side walls are poorly resistant to the support of the plate, which tends to slide there by a wedge effect increased by the obliquity above, that is to say with an amplification of force.
  • the problem of precision of their positioning and their maintenance is more acute, because they are used to perform precision machining thrust.
  • bearing faces having several facets it often happens that the user places the plate in an incorrect angular position, because the generally rounded shape of the framing walls around the housing results in the fact that they tolerate improper mounting.
  • the user can then perform a screwing, with anticipated jamming, but this screwing has no cropping effect, so that the machining of the workpiece is imprecise and, moreover, the insert, not fully plated on the bottom of the housing, can, with vibrations, free itself from the screw, not fully tightened, and damage the workpiece.
  • the tool holder and insert may also be damaged.
  • Conventionally, to resist the parasitic torque we cut, on the lateral faces, grooves extending in the direction of the thickness of the wafer, so that the area closest to the large rear face constitutes a base for fixing forming a toothed wheel, with which mesh the walls of the housing, by presentation of a corresponding grooved shape.
  • This therefore consists in replacing a perimeter of a plate delimited by a series of profiles of monotonic, flat or rounded lateral surfaces, by a perimeter generally of the same shape but wavy, that is to say non-monotonic, therefore of greater length, which thus has an increased number of accordion facets, therefore having a radial extension, compared to the clamping screw, which is more marked.
  • a solution is not suitable, due to the risk of incorrect positioning described above.
  • the present invention aims to propose a solution to this problem of positioning a wafer in the housing.
  • the invention firstly relates to a reversible cutting insert comprising a part of front layer, of cutting head, comprising mutually inclined anterior perimeter lateral faces and delimiting, with a large anterior face, a front view profile formed by a number of mutually inclined cutting edges according to said profile, and a posterior layer portion, constituting an anchoring base on a tool holder, comprising lateral faces of posterior periphery at least some of which are framing bearing faces on the walls of a housing of the tool holder, characterized by the fact that the rear periphery has a number of lateral framing support faces less than the number of cutting edges.
  • the lateral framing support faces may be planar or may define a curved periphery, the curvature possibly being variable on the same lateral framing support face, the lateral framing support faces being concave or convex.
  • the successive lateral faces of the framing support can be connected at respective angles less than 180 degrees, thus defining a said posterior periphery with orientation varying monotonically, that is to say that the successive segments of periphery "s 'roll up' to circle the perimeter, always deviating on the same side.
  • the lateral framing support faces are generally frustoconical.
  • the front layer part may have a shape of a pyramid trunk having rising edges aligned with rising edges of the posterior layer portion.
  • the part of the anterior layer is delimited by two sections of nested pyramids, with different conicities.
  • the large front face may in particular generally have a shape of a parallelogram, some of them, among pairs of lateral faces of consecutive framing support, being for example mutually inclined at an angle advantageously between 65 and 85 degrees.
  • the invention also relates to a tool holder for a cutting insert according to the invention, the tool holder comprising a housing comprising a bottom, associated with means for clamping the insert, and lateral walls for receiving the rear flanks d 'framing support of the wafer, characterized in that the housing is arranged to receive in support a first determined number of rear flanks for framing the framing of the wafer and to leave accessible a second determined number, greater than the first number, front cutting edges of the insert determined by as many lateral faces of mutually inclined front periphery.
  • the walls of the housing can, for some, be flared relative to the bottom, in order to cooperate with oblique sides.
  • FIG. 1 is a perspective view of the drill, carrying, diametrically opposite, two such plates, one of which shows an anterior face of one
  • FIG. 2 is an oblique perspective view showing a rear face and two lateral faces of one of the plates, in the inverted position .
  • the tool holder of FIG. 1 is here a drill 20 of axis of rotation 21 presenting very schematically, seen from the drawn front end, four angular sectors of approximately 90 degrees each, two of these corresponding to two recesses respective due to grooves with a slightly helical axial extension, in order to leave two substantially identical and axially opposite housings 30, 40 released, formed in the other two sectors.
  • the housing 30 has a bottom 32, extending in an axial plane and parallel to a radial direction, but without however passing through the axis 21.
  • the housing 30 thus forms a bottom-cavity 32 lowered relative to a radius limiting the sector considered, that is to say the radius representing the front end of one of the two surfaces limiting the groove considered.
  • This lowering, determining the depth of the housing 30, corresponds to a thickness value of a cutting insert 10.
  • the housing 30 is limited by a longitudinal side wall 34, located near the axis 21, and by a rear side wall 35, very approximately radial.
  • the plate 10 is here in section in parallelogram, so that the rear side wall 35 has a radially outer edge which is axially more advanced than a corner 39 of junction with the longitudinal wall 34, corner 39 therefore close to the 'axis 21.
  • the housing 30 is here with walls 34 and 35 slightly flared therefore each forming, with the bottom 32, an angle slightly exceeding 90 degrees, because the plate 10 has a truncated pyramid shape.
  • the cutting insert 10 generally has the shape of a block, and it is precisely here a micro-insert of a few millimeters on the side, having, in this example, a distance of approximately 5 mm between so-called main neighboring corners, like the plurality of here four active corners referenced 130, 140, 150, 160, that is to say at an angle closer to 90 degrees than to 180 degrees.
  • the plate 10 comprises two main faces opposite here substantially planar and parallel, namely an active front face 1, with cutting or cutting edges, and a rear face 2, connected by a series of four lateral faces constituted by two opposite sides 3, 5 respectively called front and rear, also called transverse, or radial, and by two opposite longitudinal sides 4, 6, that is to say axial.
  • the number of flanks could be different in another example.
  • the rear face 2 is a bearing face on the bottom 32 and the front face 1 is then flush with the top of the housing 30, that is to say occupies a substantially radial position.
  • the plate 10 having however a symmetry, exposed later, with respect to a proper geometric axis directed according to its thickness, there are two possible mounting positions, mutually different from 180 degrees, so that the qualifiers "front” and "rear” are only valid for these figures.
  • the axis 21 of extension of the drill 20 constitutes one.
  • the plate 10 has a face turned in the instantaneous tangential direction of its rotary movement, namely the active face 1.
  • the faces 1 and 2 are respectively called “anterior” and “ posterior “with respect to this tangential direction, and not” front “and” rear “.
  • Figure 1 shows that the plate 10 is traversed, according to its thickness, by a central fixing hole 90, determining the above geometric axis, hole in which passes freely a clamping screw 41 cooperating with a threaded hole 31 formed in the bottom 32 of the housing 30.
  • any other method of clamping may however be provided as a variant.
  • the longitudinal sides 4 and rear 5 respectively of the plate 10 are in abutment on the respective walls 34 and 35 of the housing 30.
  • the plate 10 is also locked in rotation on the bottom 32.
  • the profile of the front face 1 that is to say its contour in front view along the axis of the fixing hole 90, profile visible in Figure 1 and better discernible in Figure 2, is not perfectly square or rectangular, but it has two particularities.
  • each cutting edge 13 to 16 is thus formed of a pair of first and second segments successive 13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b, each pair of such segments forming the two branches of a "V" opened here at about 170 degrees.
  • the first segments 13a, 14a, 15a, 16a are here shorter than the second segments 13b, 14b, 15b and 16b and constitute a cutaway extension thereof, that is to say slightly folded towards the second neighboring segment.
  • the differences between the overall directions of extension of two successive cutting edges 13, 14, 15, 16 are different from 90 degrees, alternating around this value at each of the four main corners of the profile, 130 , 140, 150 and 160, defined at the successive connections of the cutting edges 13 to 16.
  • the cutting edges 13 and 14 are generally mutually inclined at 105 degrees in this example, as are the cutting edges 15 and 16.
  • the opposite cutting edges being generally parallel, it follows that the cutting edges 14 and 15 delimit an angle of 75 degrees, just like the cutting edges 13 and 16.
  • the plate 10 can be fictitiously divided into two functional parts, namely a layer constituting an anterior part 1A, for cutting or cutting a workpiece, and a layer 1B constituting a posterior part forming a fixing and framing base in the housing 30.
  • the anterior layer 1A bounded by the anterior face 1, has, from the front, the above profile with eight sides, that is to say the four pairs of segments 13a and 13b, 14a and 14b, 15a and 15b, as well as 16a and 16b.
  • the rear part 1B has only a smaller number, compared to the eight sides, of the lateral support and framing faces.
  • the rear part 1B has four such lateral faces 3B, 4B, 5B and 6B, that is to say a number which is equal to the number of front edges 13 to 16.
  • the rear part 1B here has a slightly frustoconical shape , precisely in truncated truncated pyramid with rising edges 130B, 140B, 150B and 160B, separating the successive posterior lateral surfaces of flank respectively 3B, 4B, 5B and 6B, here plane,
  • the extensions of the edges rear risers 130B, 140B, 150B and 160B pass through the front main corners 130, 140, 150, 160. Because, in the front face 1A, the segments 13a and 13b, 14a and 14b, 15a and 15b, as well as 16a and 16b, extend laterally outward relative to the parallelogram defined by the four main front corners 130, 140, 150 and 160, it follows that the front part 1A has, around the extension fictitious ment of the pyramidal shape of the rear part 1B, a bead or skirt of material supporting the eight cutting segments above.
  • the front part 1A is substantially in the form of a truncated pyramid with eight sides, the base of which is limited by the four pairs of segments 13a and '13b, 14a and 14b, 15a and 15b, 16a and 16b, and which rise by presenting four so-called main anterior rising edges 130A, 140A, 150A and 160B which are here the extension of the posterior rising edges 130B, 140B, 150B and 160B, as mentioned above.
  • Each edge such as for example the edge formed by the segments 13a and 13b is thus supported by two surfaces forming a beak, that is to say a kind of cornice with lateral extension, constituting a projection of the profile, in front view. , of the anterior face 1.
  • the secondary edges such as the edge 131A for example, have here an extension limited to less than half, here about a third, of the thickness of the plate 10, so that 'They extend at a relatively high angle, for example greater than 30 degrees, here about 45 degrees, relative to the associated side face 3B or the like.
  • the corresponding side face 3B can thus be further back from a workpiece, thus offering an increased volume of chip clearance.
  • the spouts like 13a and 13b could have more than two such cutting edges, for example if the secondary front corner 131 was truncated.
  • the anterior secondary rising edges 131A, 141A, 151A and 161A therefore determine a taper angle greater than that of the posterior part 1B and therefore also of the four main front rising edges 130A, 140A, 150A and 160A. Therefore, the front part 1A does not have exactly the shape of a segment of pyramid, but is formed by the union of two sections of overlapping pyramids, with different conicities. It will now be specified, with reference to FIG.
  • the front anterior lateral surface 3A defining a section of the bead, consists of the two successive anterior flat lateral surfaces 3a and 3b, mutually inclined, respectively limited by the cutting edges 13a and 13b and separated by the anterior secondary rising edge 131.
  • the trihedral thus formed constitutes a lateral cutting beak.
  • the flanks 4 to 6 likewise have the pairs of homologous cutting segments 14a and 14b, 15a and 15b as well as 16a and 16b.
  • the anterior lateral surfaces 3a and 3b come to cut the posterior lateral surface 3B along two respective straight lines 13c and 13d in V open towards the anterior face 1.
  • the anterior part 1A has therefore, in this example, a variable thickness, and in particular zero at the level of the front main corners 130, 140, 150 and 160, where the bead cancels locally.
  • the bead Over the thickness of the total periphery of the large anterior face 1, the bead thus forms four festoons, each in the form of a beak having a lateral overflow extension and a thickness which are maximum at the level of the secondary corners 131, 141, 151 and 161 of the beak point, and a minimum thickness, here zero, at the level of the main corners 130, 140, 150 and 160 where they are connected.
  • the current thickness of the four nozzles on the total periphery defines a functional thickness of the front part 1A, and, by difference with the constant total thickness of the plate 10, determines a functional thickness of the rear part 1B.
  • the front main corners 130, 140, 150 and 160 do not constitute the extension of the rising edges of the rear part pyramid 1B, that is to say that the front main rising edges 130A, 140A, 150A and 160A have a conicity independent of that of the posterior part 1B, for example equal to that of the anterior secondary rising edges 131A, 141A, 151A and 161A, to effectively define a trunk of the pyramid, or else so that the bead provides optimal support over the entire length of the eight segments 13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b, while having a desired draft angle.
  • the minimum thickness presented by the bead, at the main corners 130, 140, 150 and 160, is not zero.
  • the posterior layer part 1B could form a sole of constant thickness, that is to say that the overflow V would no longer form a trihedron, but would retain its shape over the entire thickness of the anterior part. 1A.
  • the radial rear side wall 35 of the housing 30 has a suitable shape, here flat, to receive as much support the front rear side surface 3B as a homologous rear rear side surface of similar shape and belonging to the rear flank 5, this who is the case of Figure 1.
  • the longitudinal side wall 34 has the same kind of shape, adapted to cooperate with any of the rear parts 4B and 6B of the sides 4 and 6.
  • the walls 34 and 35 s extend, substantially axially and approximately radially, in a rectilinear manner, in accordance with the two posterior flanks considered 4B and 5B or 6B and 3B, of support and framing of the posterior pyramid.
  • a posterior rising edge coming from the main corner 140 homologous with the posterior rising edge 160B coming from the main corner 160, constitutes a kind of tooth having a good radial extension with respect to the axis of the fixing hole 90, and it thus offers a surface less inclined on a radius of the axis of the hole 90 than would be a tooth defined by two surfaces mutually inclined at 90 degrees.
  • the walls 34 and 35 may also, as shown in FIG. 1, be provided, to each comprise, in the upper part of the housing 30, an area having a shape of a recessed V-shaped cavity in order to provide additional force. support by cooperation with the anterior flank zones 4A and 5A or 6A and 3A, even if this complement is less effective than for the posterior part 1B, with rectilinear flanks.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Processing Of Stones Or Stones Resemblance Materials (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)
  • Drilling Tools (AREA)
  • Milling Processes (AREA)

Abstract

The inventive reversible cutting insert comprises the part of a front layer (1A) provided with the lateral faces of a front circumference (3A, 4A, 5A, 6A) defining together with a large front face (1) a given number of cutting edges (13a, 13b; 14a,14b; 15a,15b; 16a, 16b) and the part of a rear layer (1B) provided with lateral faces of a rear circumference whose at least certain faces are embodied in the form of faces supporting a frame (3B, 4B, 5B, 6B) on the walls of a toolholder housing (30), wherein the number of the frame supporting faces (3B, 4B, 5B, 6B) is less than the number of cutting edges (13a, 13b; 14a,14b; 15a,15b; 16a, 16b).

Description

Plaquette de coupe à nombre limité de faces de cadrage Cutting insert with limited number of framing faces
La présente invention concerne le bridage de microplaquettes de coupe amovibles sur un porte-outil, comme par exemple un foret . De façon classique, une plaquette de coupe amovible est plaquée contre le fond d'un logement du porte-outil par une vis de bridage traversant librement un trou central de la plaquette de coupe pour venir en prise avec un trou taraudé dans le fond du logement. Toutefois, comme les deux filetages en prise sont prévus avec un jeu mutuel pour faciliter le vissage, ce jeu se retrouve en tant qu'incertitude dans le cadrage de la plaquette de coupe sur ce fond. En outre, la pièce usinée et les vibrations sont susceptibles d'appliquer à la plaquette un couple de rotation autour de la vis de bridage. Or, la force de serrage de la vis est insuffisante, compte tenu du coefficient de frottement entre la plaquette et le fond, pour exercer un placage suffisant pour s'opposer à toute translation ou toute rotation par rapport à la vis de bridage. De ce fait, le logement présente une paroi latérale plane, et même en général deux, respectivement longitudinale et axiale par rapport à un axe général du porte-outil, servant d'appui à des faces latérales planes correspondantes de la plaquette, pour former, avec le fond, un trièdre de réception d'un coin de la plaquette, ainsi bloquée en translation et en rotation. La plaquette a donc globalement deux grandes faces parallèles rectangulaires, antérieure et postérieure, reliées par quatre faces latérales pl'anes définissant quatre arêtes rectilignes avec la grande face antérieure, deux faces latérales successives servant d'appui de cadrage, les deux autres faces latérales pouvant assurer cette fonction si la plaquette est réversible. Bien évidemment, le logement est ouvert axialement en bout et/ou latéralement pour laisser accessible l'une des arêtes ci- dessus, en tant qu'arête de coupe. Les arêtes de coupe doivent toutefois, pour certaines applications, présenter, en vue en plan, un profil de forme anguleuse, c'est-à-dire qu'un côté du rectangle classique délimitant la grande face antérieure est alors remplacé par deux segments successifs non alignés, formant par exemple une pointe latérale, ou, en d'autres termes, l'arête de coupe comporte un tronçon d'extrémité en biseau ou pan coupé, rabattu vers l'arête suivante. Si la plaquette est réversible, l'arête de coupe du côté opposé présente donc la même forme anguleuse. Comme cette forme est déterminée par 1 ' intersection entre la grande face antérieure et la face latérale d'appui respective, chacune des faces latérales d'appui doit donc alors en principe être prévue sous forme de deux zones planes mutuellement inclinées, en vue en plan de la plaquette. En bref, le rectangle classique limitant la grande face antérieure est remplacé par un hexagone et cette forme hexagonale vaut pour toutes les sections parallèles aux grandes faces, c'est-à-dire pour les flancs d'appui de cadrage. On passe à un octogone si la grande face antérieure est limitée par quatre arêtes, toutes de coupe, qui sont en fait chacune ainsi divisées en deux arêtes de coupe. La ou les deux parois d'appui prévues dans le logement doivent donc être adaptées à la nouvelle forme des faces latérales, c'est-à-dire être chacune divisées en deux parties planes mutuellement inclinées, en vue en plan du logement. De ce fait, le pourtour du trièdre de réception de la plaquette, initialement défini par deux parois latérales perpendiculaires représentant la moitié de la périphérie de la plaquette, est maintenant défini par quatre surfaces latérales qui, certes, représentent toujours la moitié de cette périphérie, mais limitent maintenant le pourtour du fond du logement selon une forme moins anguleuse, c'est-à-dire à tronçons ou facettes d'allure globalement arrondie. En résumé, et supposant, pour simplifier, que tous les N angles de pourtour sont égaux, chacun de ceux-ci vaut 180 - 360/N degrés. Pour un nombre N élevé, cette forme globalement arrondie entraîne le fait que les appuis des faces latérales de la plaquette, sur les parois du logement, s'exercent avec une obliquité accrue lorsqu'il s'agit de résister au couple parasite de rotation autour de la vis ou de tout autre moyen de bridage. En d'autres termes, le logement et la plaquette ont des surfaces de cadrage latérales coopérantes qui présentent, par rapport à l'axe de la vis, une composante de surface à extension radiale qui est maintenant réduite, c'est-à-dire une faible extension dans une direction perpendiculaire à la force circonférentielle du couple parasite. De ce fait, les parois latérales résistent mal à l'appui de la plaquette, qui tend à y glisser par un effet de coin accru par l'obliquité ci-dessus, c'est-à-dire avec une amplification de force . Lorsqu'il s'agit de micro-plaquettes, c'est-à-dire de plaquettes de quelques millimètres de côté, le problème de précision de leur positionnement et de leur maintien est plus aigu, car elles servent à effectuer un usinage de précision poussée. Dans le cas ci-dessus de faces d'appui présentant plusieurs facettes, il arrive souvent que l'utilisateur place la plaquette dans une position angulaire incorrecte, car l'allure globalement arrondie des parois de cadrage en pourtour du logement entraîne le fait qu'elles tolèrent un mauvais montage. L'utilisateur peut ainsi effectuer ensuite un vissage, avec coincement anticipé, mais ce vissage n'a aucun effet de recadrage, si bien que l'usinage de la pièce à usiner est imprécis et, en outre, la plaquette, non entièrement plaquée sur le fond du logement, peut, avec les vibrations, se libérer de la vis, non serrée à fond, et endommager la pièce à usiner. Le porte-outil et la plaquette peuvent aussi être endommagés. De façon classique, pour résister au couple parasite, on taille, sur les faces latérales, des rainures s ' étendant selon la direction de l'épaisseur de la plaquette, afin que la zone la plus proche de la grande face arrière constitue une base de fixation formant une roue dentée, avec laquelle engrènent les parois du logement, par présentation d'une forme cannelée correspondante. Cela consiste donc à remplacer un pourtour de plaquette délimité par une suite de profils de surfaces latérales monotones, planes ou arrondies, par un pourtour globalement de même forme mais ondulé, c'est-à-dire non monotone, donc de plus grande longueur, qui présente ainsi un nombre accru de facettes en accordéon, donc présentant une extension radiale, par rapport à la vis de bridage, qui est plus marquée. Une telle solution ne convient pas, du fait du risque de mauvais positionnement exposé ci-dessus. La présente invention vise à proposer une solution à ce problème de positionnement d'une plaquette dans le logement . A cet effet, l'invention concerne tout d'abord une plaquette de coupe réversible comportant une partie de couche antérieure, de tête de coupe, comportant des faces latérales de pourtour antérieur mutuellement inclinées et délimitant, avec une grande face antérieure, un profil de vue avant formé par un certain nombre d'arêtes de coupe mutuellement inclinées selon le dit profil, et une partie de couche postérieure, constituant une base d'ancrage sur un porte-outil, comportant des faces latérales de pourtour postérieur dont au moins certaines sont des faces d'appui de cadrage sur des parois d'un logement du porte-outil, caractérisée par le fait que le pourtour postérieur comporte un nombre de faces latérales d'appui de cadrage inférieur au nombre d'arêtes de coupe. Ainsi, la solution proposée va à 1 ' encontre de la solution de l'art antérieur ci-dessus, puisqu'on recherche ici à avoir un minimum de faces latérales d'appui de cadrage . Les faces latérales d'appui de cadrage peuvent être planes ou bien peuvent définir un pourtour courbe, la courbure étant éventuellement variable sur une même face latérale d'appui de cadrage, les faces latérales d'appui de cadrage étant concaves ou convexes . Les faces latérales successives d'appui de cadrage peuvent se raccorder selon des angles respectifs inférieurs à 180 degrés, pour ainsi définir un dit pourtour postérieur à orientation variant de façon monotone, c'est-à-dire que les segments successifs de pourtour "s'enroulent" pour boucler le pourtour, en déviant toujours d'un même côté. Dans une forme de réalisation, les faces latérales d'appui de cadrage sont globalement tronconiques . Pour sa part, la partie de couche antérieure peut présenter une forme de tronc de pyramide présentant des arêtes montantes alignées avec des arêtes montantes de la partie de couche postérieure. Dans une forme de réalisation particulière, la partie de couche antérieure est délimitée par deux tronçons de pyramides imbriquées, à conicités différentes. La grande face antérieure peut en particulier présenter globalement une forme de parallélogramme, certaines, parmi des paires de faces latérales d'appui de cadrage consécutives, étant par exemple mutuellement inclinées d'un angle compris avantageusement entre 65 et 85 degrés . L'invention concerne aussi un porte-outil pour une plaquette de coupe selon l'invention, le porte-outil comprenant un logement comportant un fond, associé à des moyens de bridage de la plaquette, et des parois latérales de réception de flancs postérieurs d'appui de cadrage de la plaquette, caractérisé par le fait que le logement est agencé pour recevoir en appui un premier nombre déterminé de flancs postérieurs d'appui de cadrage de la plaquette et pour laisser accessibles un second nombre déterminé, supérieur au premier nombre, d'arêtes de coupe antérieures de la plaquette déterminées par autant de faces latérales de pourtour antérieur mutuellement inclinées. Les parois du logement peuvent, pour certaines, être évasées par rapport au fond, afin de coopérer avec des flancs obliques. Les parois du logement sont de préférence mutuellement inclinées d'un angle situé dans une plage allant de 65 à 85 degrés, pour qu'ainsi une plaquette de forme complémentaire y soit bien calée contre toute rotation parasite. Les parois du logement sont en outre avantageusement adaptées pour recevoir en outre, en appui de cadrage, des flancs antérieurs de support des arêtes de coupe antérieures de la plaquette. La présente invention sera mieux comprise à l'aide de la description suivante d'une forme de réalisation d'un foret muni de plaquettes, selon l'invention, en référence au dessin annexé, sur lequel : la figure 1 est une vue en perspective du foret, portant, diamétralement opposées, deux telles plaquettes, dont on voit une face antérieure de l'une, et la figure 2 est une vue en perspective oblique montrant une face postérieure et deux faces latérales d'une des plaquettes, en position retournée. Le porte-outil de la figure 1 est ici un foret 20 d'axe de rotation 21 présentant très schématiquement , vue depuis l'extrémité avant dessinée, quatre secteurs angulaires d'environ 90 degrés chacun, deux de ceux-ci correspondant à deux évidements respectifs dus à des cannelures à extension axiale légèrement hélicoïdale, afin de laisser dégagés deux logements 30, 40 sensiblement identiques et axialement opposés, ménagés dans les deux autres secteurs. Le logement 30 comporte un fond 32, s ' étendant dans un plan axial et parallèlement à une direction radiale, mais sans toutefois passer par l'axe 21. Le logement 30 forme ainsi une cavité à fond 32 abaissé par rapport à un rayon limitant le secteur considéré, c'est-à- dire le rayon représentant l'extrémité avant de l'une des deux surfaces limitant la cannelure considérée. Cet abaissement, déterminant la profondeur du logement 30, correspond à une valeur d'épaisseur d'une plaquette de coupe 10. Le logement 30 est limité par une paroi latérale longitudinale 34, située à proximité de l'axe 21, et par une paroi latérale arrière 35, très approximativement radiale. En fait, la plaquette 10 est ici à section en parallélogramme, si bien que la paroi latérale arrière 35 présente un bord radialement externe qui est axialement plus avancé qu'un coin 39 de jonction avec la paroi longitudinale 34, coin 39 donc proche de l'axe 21. De même, le logement 30 est ici à parois 34 et 35 légèrement évasées formant donc chacune, avec le fond 32, un angle dépassant légèrement 90 degrés, car la plaquette 10 présente une forme de tronc de pyramide. Comme le montrent les figures 1 et 2 , la plaquette de coupe 10 présente globalement la forme d'un pavé, et il s'agit précisément ici d'une micro-plaquette de quelques millimètres de côté, présentant, dans cet exemple, une distance d' approximativement 5 mm entre coins voisins dits principaux, comme la pluralité d'ici quatre coins actifs référencés 130, 140, 150, 160, c'est-à-dire à angle plus proche de 90 degrés que de 180 degrés. La plaquette 10 comporte deux faces principales opposées ici sensiblement planes et parallèles, à savoir une face antérieure 1 active, à arêtes de taille ou coupe, et une face postérieure 2, reliées par une suite de quatre faces latérales constituées par deux flancs opposés 3, 5 respectivement dits avant et arrière, encore appelés transversaux, ou radiaux, et par deux flancs opposés longitudinaux 4, 6, c'est-à-dire axiaux. Le nombre de flancs pourrait être différent dans un autre exemple. La face postérieure 2 est une face d'appui sur le fond 32 et la face antérieure 1 affleure alors en haut du logement 30, c'est-à-dire occupe une position sensiblement radiale. La plaquette 10 présentant toutefois une symétrie, exposée plus loin, par rapport à un axe géométrique propre dirigé selon son épaisseur, il existe deux positions possibles de montage, mutuellement différentes de 180 degrés, si bien que les qualificatifs "avant" et "arrière" ne sont valables que pour les présentes figures . Dans la présente description, l'axe 21 d'extension du foret 20 constitue une. référence de position et d'orientation de la plaquette 10, et les mots "avant" et "arrière" sont ici utilisés lorsqu'il est fait référence à la position ou l'orientation d'un élément considéré par rapport à l'axe 21. Par ailleurs, la plaquette 10 comporte une face tournée selon la direction tangentielle instantanée de son mouvement rotatif, à savoir la face active 1. Afin d'éviter tout risque de confusion, les faces 1 et 2 sont respectivement dites "antérieure" et "postérieure" vis-à-vis de cette direction tangentielle, et non "avant" et "arrière". La figure 1 montre que la plaquette 10 est traversée, selon son épaisseur, par un trou de fixation central 90, déterminant l'axe géométrique ci-dessus, trou dans lequel passe librement une vis de bridage 41 coopérant avec un trou taraudé 31 ménagé dans le fond 32 du logement 30. Tout autre mode de bridage peut toutefois être prévu en variante. Dans la position de bridage, les flancs respectivement longitudinal 4 et arrière 5 de la plaquette 10 se trouvent en appui sur les parois respectives 34 et 35 du logement 30. De ce fait, la plaquette 10 est aussi bloquée en rotation sur le fond 32. Le profil de la face antérieure 1, c'est-à-dire son contour en vue de face selon l'axe du trou de fixation 90, profil visible sur la figure 1 et mieux discernable sur la figure 2, n'est pas parfaitement carré ou rectangulaire, mais il présente deux particularités. Tout d'abord, et essentiellement, la face antérieure 1 délimite, avec les quatre flancs 3 à 6, quatre arêtes, toutes de coupe dans cet exemple, respectivement 13, 14, 15, 16, qui ne sont pas rectilignes mais, au contraire, constituent chacune un tronçon de contour en relief latéral, c'est-à-dire s ' écartant radialement du trou central 90. Dans cet exemple, chaque arête de coupe 13 à 16 est ainsi formée d'une paire de premier et second segments successifs 13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b, chaque paire de tels segments formant les deux branches d'un "V" ouvert ici à environ 170 degrés. Les premiers segments 13a, 14a, 15a, 16a sont ici plus courts que les seconds segments 13b, 14b, 15b et 16b et en constituent un prolongement en pan coupé, c'est-à-dire légèrement rabattu vers le second segment voisin. Ensuite, dans cet exemple, les écarts entre les directions globales d'extension de deux arêtes de coupe 13, 14, 15, 16 successives sont différents de 90 degrés, en alternant autour de cette valeur à chacun des quatre coins principaux du profil, 130, 140, 150 et 160, définis aux raccordements successifs des arêtes de coupe 13 à 16. Ainsi, les arêtes de coupe 13 et 14 sont globalement mutuellement inclinées à 105 degrés dans cet exemple, de même que les arêtes de coupe 15 et 16. Les arêtes de coupe opposées étant globalement parallèles, il s'ensuit que les arêtes de coupe 14 et 15 délimitent un angle de 75 degrés, tout comme les arêtes de coupe 13 et 16. Comme évoqué ci- dessus, il s'agit des angles entre les directions globales d'extension des arêtes de coupe considérées, tandis que l'angle que présentent les deux segments du coin principal considéré 130, 140, 150 et 160, peut être un peu supérieur, du fait du pan coupé . Sur la figure 1, un tel angle aigu de 75 degrés se présente donc pour le coin alors actif 160, c'est-à-dire radialement externe et axialement en avant du logement 30, afin de pouvoir tracer un sillon dans la matière usinée. L'angle aigu ci-dessus peut toutefois être choisi à des valeurs autres, selon l'application particulière visée, la plage allant de 65 à 85 degrés étant considérée comme préférable . Sur la figure 2, la plaquette 10 est dessinée en position retournée, vue de l'arrière pour mieux illustrer des reliefs latéraux de celle-ci. La plaquette 10 peut être fictivement divisée en deux parties fonctionnelles, à savoir une couche constituant une partie antérieure 1A, pour la coupe ou taille d'une pièce à usiner, et une couche 1B constituant une partie postérieure formant une embase de fixation et de cadrage dans le logement 30. La couche antérieure 1A, limitée par la face antérieure 1, en présente, de face, le profil ci-dessus à huit pans, c'est- à-dire les quatre paires de segments 13a et 13b, 14a et 14b, 15a et 15b, ainsi que 16a et 16b. Toutefois, la partie postérieure 1B ne présente qu'un nombre plus réduit, par rapport aux huit pans, de faces latérales d'appui et de cadrage. Précisément, la partie postérieure 1B présente quatre telles faces latérales 3B, 4B, 5B et 6B, c'est-à-dire un nombre qui est égal au nombre des arêtes avant 13 à 16. La partie postérieure 1B présente ici une forme légèrement tronconique, précisément en tronc de pyramide tronquée à arêtes montantes 130B, 140B, 150B et 160B, séparant les surfaces latérales postérieures successives de flanc respectivement 3B, 4B, 5B et 6B, ici planes,The present invention relates to the clamping of removable cutting chips on a tool holder, such as for example a drill. Typically, a removable cutting insert is pressed against the bottom of a tool holder housing by a clamping screw freely passing through a central hole in the cutting insert to engage a tapped hole in the bottom of the housing . However, as the two threads in engagement are provided with mutual play to facilitate screwing, this play is found as uncertainty in the framing of the cutting insert on this bottom. In addition, the workpiece and vibrations are likely to apply a torque to the wafer around the clamping screw. However, the tightening force of the screw is insufficient, taking into account the coefficient of friction between the plate and the bottom, to exert sufficient plating to oppose any translation or any rotation relative to the clamping screw. Therefore, the housing has a flat side wall, and even in general two, respectively longitudinal and axial with respect to a general axis of the tool holder, serving to support the corresponding flat side faces of the insert, to form, with the bottom, a trihedron for receiving a corner of the plate, thus blocked in translation and in rotation. The wafer therefore has generally two large rectangular parallel faces, front and rear, connected by four side s' anes faces defining four straight edges with large front surface, two successive lateral faces serving as a support of framing, the other two side faces can perform this function if the plate is reversible. Obviously, the housing is open axially at the end and / or laterally to leave one of the above edges accessible, as a cutting edge. The cutting edges must, however, for certain applications, have, in plan view, an angular profile, that is to say that one side of the classic rectangle delimiting the large anterior face is then replaced by two successive segments. not aligned, for example forming a lateral point, or, in other words, the cutting edge comprises an end section in bevel or cutaway, folded towards the next edge. If the insert is reversible, the cutting edge on the opposite side therefore has the same angular shape. As this shape is determined by the intersection between the large anterior face and the respective lateral support face, each of the lateral support faces must therefore in principle be provided in the form of two mutually inclined flat zones, in plan view of the brochure. In short, the classic rectangle limiting the large front face is replaced by a hexagon and this hexagonal shape applies to all the sections parallel to the large faces, that is to say for the framing support flanks. We pass to an octagon if the large anterior face is limited by four edges, all of cutting, which are in fact each thus divided into two cutting edges. The one or two support walls provided in the housing must therefore be adapted to the new shape of the lateral faces, that is to say each be divided into two mutually inclined plane parts, in plan view of the housing. Therefore, the periphery of the receiving trihedron of the wafer, initially defined by two perpendicular side walls representing half of the periphery of the wafer, is now defined by four side surfaces which, admittedly, always represent half of this periphery, but now limit the periphery of the bottom of the housing according to a less angular shape, that is to say with sections or facets of generally rounded appearance. In summary, and supposing, for simplicity, that all the N perimeter angles are equal, each of these is worth 180 - 360 / N degrees. For a high number N, this generally rounded shape results in the fact that the supports of the lateral faces of the plate, on the walls of the housing, are exerted with increased obliquity when it is a question of resisting the parasitic torque of rotation around of the screw or any other clamping means. In other words, the housing and the plate have cooperating lateral framing surfaces which have, relative to the axis of the screw, a surface component with radial extension which is now reduced, that is to say a small extension in a direction perpendicular to the circumferential force of the parasitic torque. Therefore, the side walls are poorly resistant to the support of the plate, which tends to slide there by a wedge effect increased by the obliquity above, that is to say with an amplification of force. When it comes to micro-wafers, that is to say wafers a few millimeters aside, the problem of precision of their positioning and their maintenance is more acute, because they are used to perform precision machining thrust. In the above case of bearing faces having several facets, it often happens that the user places the plate in an incorrect angular position, because the generally rounded shape of the framing walls around the housing results in the fact that they tolerate improper mounting. The user can then perform a screwing, with anticipated jamming, but this screwing has no cropping effect, so that the machining of the workpiece is imprecise and, moreover, the insert, not fully plated on the bottom of the housing, can, with vibrations, free itself from the screw, not fully tightened, and damage the workpiece. The tool holder and insert may also be damaged. Conventionally, to resist the parasitic torque, we cut, on the lateral faces, grooves extending in the direction of the thickness of the wafer, so that the area closest to the large rear face constitutes a base for fixing forming a toothed wheel, with which mesh the walls of the housing, by presentation of a corresponding grooved shape. This therefore consists in replacing a perimeter of a plate delimited by a series of profiles of monotonic, flat or rounded lateral surfaces, by a perimeter generally of the same shape but wavy, that is to say non-monotonic, therefore of greater length, which thus has an increased number of accordion facets, therefore having a radial extension, compared to the clamping screw, which is more marked. Such a solution is not suitable, due to the risk of incorrect positioning described above. The present invention aims to propose a solution to this problem of positioning a wafer in the housing. To this end, the invention firstly relates to a reversible cutting insert comprising a part of front layer, of cutting head, comprising mutually inclined anterior perimeter lateral faces and delimiting, with a large anterior face, a front view profile formed by a number of mutually inclined cutting edges according to said profile, and a posterior layer portion, constituting an anchoring base on a tool holder, comprising lateral faces of posterior periphery at least some of which are framing bearing faces on the walls of a housing of the tool holder, characterized by the fact that the rear periphery has a number of lateral framing support faces less than the number of cutting edges. Thus, the proposed solution goes against the solution of the prior art above, since we are seeking here to have a minimum of lateral framing support faces. The lateral framing support faces may be planar or may define a curved periphery, the curvature possibly being variable on the same lateral framing support face, the lateral framing support faces being concave or convex. The successive lateral faces of the framing support can be connected at respective angles less than 180 degrees, thus defining a said posterior periphery with orientation varying monotonically, that is to say that the successive segments of periphery "s 'roll up' to circle the perimeter, always deviating on the same side. In one embodiment, the lateral framing support faces are generally frustoconical. For its part, the front layer part may have a shape of a pyramid trunk having rising edges aligned with rising edges of the posterior layer portion. In a particular embodiment, the part of the anterior layer is delimited by two sections of nested pyramids, with different conicities. The large front face may in particular generally have a shape of a parallelogram, some of them, among pairs of lateral faces of consecutive framing support, being for example mutually inclined at an angle advantageously between 65 and 85 degrees. The invention also relates to a tool holder for a cutting insert according to the invention, the tool holder comprising a housing comprising a bottom, associated with means for clamping the insert, and lateral walls for receiving the rear flanks d 'framing support of the wafer, characterized in that the housing is arranged to receive in support a first determined number of rear flanks for framing the framing of the wafer and to leave accessible a second determined number, greater than the first number, front cutting edges of the insert determined by as many lateral faces of mutually inclined front periphery. The walls of the housing can, for some, be flared relative to the bottom, in order to cooperate with oblique sides. The walls of the housing are preferably mutually inclined at an angle in a range from 65 to 85 degrees, so that a plate of complementary shape is well wedged against any parasitic rotation. The walls of the housing are also advantageously adapted to further receive, in framing support, front flanks for supporting the front cutting edges of the insert. The present invention will be better understood with the aid of the following description of an embodiment of a drill fitted with inserts, according to the invention, with reference to the appended drawing, in which: FIG. 1 is a perspective view of the drill, carrying, diametrically opposite, two such plates, one of which shows an anterior face of one, and FIG. 2 is an oblique perspective view showing a rear face and two lateral faces of one of the plates, in the inverted position . The tool holder of FIG. 1 is here a drill 20 of axis of rotation 21 presenting very schematically, seen from the drawn front end, four angular sectors of approximately 90 degrees each, two of these corresponding to two recesses respective due to grooves with a slightly helical axial extension, in order to leave two substantially identical and axially opposite housings 30, 40 released, formed in the other two sectors. The housing 30 has a bottom 32, extending in an axial plane and parallel to a radial direction, but without however passing through the axis 21. The housing 30 thus forms a bottom-cavity 32 lowered relative to a radius limiting the sector considered, that is to say the radius representing the front end of one of the two surfaces limiting the groove considered. This lowering, determining the depth of the housing 30, corresponds to a thickness value of a cutting insert 10. The housing 30 is limited by a longitudinal side wall 34, located near the axis 21, and by a rear side wall 35, very approximately radial. In fact, the plate 10 is here in section in parallelogram, so that the rear side wall 35 has a radially outer edge which is axially more advanced than a corner 39 of junction with the longitudinal wall 34, corner 39 therefore close to the 'axis 21. Similarly, the housing 30 is here with walls 34 and 35 slightly flared therefore each forming, with the bottom 32, an angle slightly exceeding 90 degrees, because the plate 10 has a truncated pyramid shape. As shown in Figures 1 and 2, the cutting insert 10 generally has the shape of a block, and it is precisely here a micro-insert of a few millimeters on the side, having, in this example, a distance of approximately 5 mm between so-called main neighboring corners, like the plurality of here four active corners referenced 130, 140, 150, 160, that is to say at an angle closer to 90 degrees than to 180 degrees. The plate 10 comprises two main faces opposite here substantially planar and parallel, namely an active front face 1, with cutting or cutting edges, and a rear face 2, connected by a series of four lateral faces constituted by two opposite sides 3, 5 respectively called front and rear, also called transverse, or radial, and by two opposite longitudinal sides 4, 6, that is to say axial. The number of flanks could be different in another example. The rear face 2 is a bearing face on the bottom 32 and the front face 1 is then flush with the top of the housing 30, that is to say occupies a substantially radial position. The plate 10 having however a symmetry, exposed later, with respect to a proper geometric axis directed according to its thickness, there are two possible mounting positions, mutually different from 180 degrees, so that the qualifiers "front" and "rear" are only valid for these figures. In the present description, the axis 21 of extension of the drill 20 constitutes one. position and orientation reference of the plate 10, and the words "front" and "rear" are used here when reference is made to the position or orientation of an element considered with respect to the axis 21 Furthermore, the plate 10 has a face turned in the instantaneous tangential direction of its rotary movement, namely the active face 1. In order to avoid any risk of confusion, the faces 1 and 2 are respectively called "anterior" and " posterior "with respect to this tangential direction, and not" front "and" rear ". Figure 1 shows that the plate 10 is traversed, according to its thickness, by a central fixing hole 90, determining the above geometric axis, hole in which passes freely a clamping screw 41 cooperating with a threaded hole 31 formed in the bottom 32 of the housing 30. Any other method of clamping may however be provided as a variant. In the clamping position, the longitudinal sides 4 and rear 5 respectively of the plate 10 are in abutment on the respective walls 34 and 35 of the housing 30. As a result, the plate 10 is also locked in rotation on the bottom 32. The profile of the front face 1, that is to say its contour in front view along the axis of the fixing hole 90, profile visible in Figure 1 and better discernible in Figure 2, is not perfectly square or rectangular, but it has two particularities. First, and essentially, the front face 1 delimits, with the four sides 3 to 6, four edges, all of cut in this example, respectively 13, 14, 15, 16, which are not straight but, on the contrary , each constitute a section of contour in lateral relief, that is to say deviating radially from the central hole 90. In this example, each cutting edge 13 to 16 is thus formed of a pair of first and second segments successive 13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b, each pair of such segments forming the two branches of a "V" opened here at about 170 degrees. The first segments 13a, 14a, 15a, 16a are here shorter than the second segments 13b, 14b, 15b and 16b and constitute a cutaway extension thereof, that is to say slightly folded towards the second neighboring segment. Then, in this example, the differences between the overall directions of extension of two successive cutting edges 13, 14, 15, 16 are different from 90 degrees, alternating around this value at each of the four main corners of the profile, 130 , 140, 150 and 160, defined at the successive connections of the cutting edges 13 to 16. Thus, the cutting edges 13 and 14 are generally mutually inclined at 105 degrees in this example, as are the cutting edges 15 and 16. The opposite cutting edges being generally parallel, it follows that the cutting edges 14 and 15 delimit an angle of 75 degrees, just like the cutting edges 13 and 16. As mentioned above, these are the angles between the overall directions of extension of the cutting edges considered, while the angle presented by the two segments of the main corner considered 130, 140, 150 and 160, may be a little greater, due to the cutaway. In FIG. 1, such an acute angle of 75 degrees therefore appears for the then active corner 160, that is to say radially external and axially in front of the housing 30, in order to be able to trace a groove in the machined material. The above acute angle may, however, be chosen at other values, depending on the particular application, the range from 65 to 85 degrees being considered preferable. In Figure 2, the plate 10 is drawn in the inverted position, viewed from the rear to better illustrate lateral reliefs thereof. The plate 10 can be fictitiously divided into two functional parts, namely a layer constituting an anterior part 1A, for cutting or cutting a workpiece, and a layer 1B constituting a posterior part forming a fixing and framing base in the housing 30. The anterior layer 1A, bounded by the anterior face 1, has, from the front, the above profile with eight sides, that is to say the four pairs of segments 13a and 13b, 14a and 14b, 15a and 15b, as well as 16a and 16b. However, the rear part 1B has only a smaller number, compared to the eight sides, of the lateral support and framing faces. Specifically, the rear part 1B has four such lateral faces 3B, 4B, 5B and 6B, that is to say a number which is equal to the number of front edges 13 to 16. The rear part 1B here has a slightly frustoconical shape , precisely in truncated truncated pyramid with rising edges 130B, 140B, 150B and 160B, separating the successive posterior lateral surfaces of flank respectively 3B, 4B, 5B and 6B, here plane,
• appartenant aux flancs respectifs 3, 4, 5, 6 et limitant la partie postérieure 1B . Les angles ci-dessus de 75 et 105 degrés, entre les directions globales d'extension des arêtes de coupe 13 à 16 se retrouvent de même au niveau du pourtour de la face postérieure 2 et donc aussi au niveau de toute coupe, parallèle à celle-ci, des surfaces latérales de flanc postérieures 3B, 4B, 5B et 6B . La plage angulaire préférée évoquée plus haut peut toutefois être légèrement modifiée par une définition différente, plus conforme à la définition de l'angle d'inclinaison entre deux surfaces, en considérant à cet effet un plan de coupe qui soit exactement perpendiculaire aux deux faces latérales postérieures successives coupées, comme 3B et 4B, c'est-à-dire un plan de coupe qui, du fait de la conicité, se trouve être légèrement incliné par rapport aux grandes faces 1 et 2. Dans cet exemple, les prolongements des arêtes montantes postérieures 130B, 140B, 150B et 160B passent par les coins principaux antérieurs 130, 140, 150, 160. Du fait que, dans la face antérieure 1A, les segments 13a et 13b, 14a et 14b, 15a et 15b, ainsi que 16a et 16b, débordent latéralement vers l'extérieur par rapport au parallélogramme défini par les quatre coins principaux antérieurs 130, 140, 150 et 160, il en résulte que la partie antérieure 1A présente, autour du prolongement fictif de la forme pyramidale de la partie postérieure 1B, un bourrelet ou jupe de matière supportant les huit segments de coupe ci-dessus. La partie antérieure 1A est sensiblement en forme de pyramide tronquée à huit côtés, dont la base est limitée par les quatre paires de segments 13a et '13b, 14a et 14b, 15a et 15b, 16a et 16b, et qui s'élèvent en présentant quatre arêtes montantes antérieures dites principales 130A, 140A, 150A et 160B qui sont ici le prolongement des arêtes montantes postérieures 130B, 140B, 150B et 160B, comme évoqué plus haut. En outre, quatre arêtes antérieures dites secondaires 131A, 141A, 151A et 161A montent depuis quatre coins antérieurs dits secondaires 131, 141, 151, 161 déterminés par la pointe du V de chaque paire de segments 13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b. Il est ainsi délimité, dans les flancs 3 à 6, quatre zones de flanc antérieures 3A, 4A, 5A et 6A, chacune comportant deux surfaces successives d'orientations différentes, 3a et 3b, 4a et 4b, 5a et 5b, 6a et 6b, respectivement situées sous les deux segments considérés. Chaque arête comme par exemple l'arête formée par les segments 13a et 13b est ainsi supportée par deux surfaces formant un bec, c'est-à- dire une sorte de corniche à extension latérale, constituant une saillie du profil, en vue de face, de la face antérieure 1. En outre, les arêtes secondaires comme l'arête 131A, par exemple, ont ici une extension limitée à moins de la moitié, ici environ un tiers, de l'épaisseur de la plaquette 10, de sorte qu'elles s'étendent selon un angle relativement élevé, par exemple supérieur à 30 degrés, ici d'environ 45 degrés, par rapport à la face latérale associée 3B ou autre. La face latérale correspondante 3B pourra ainsi être plus en recul d'une pièce à usiner, offrant donc un volume accru de dégagement des copeaux. En variante, il pourrait être prévu que les becs comme 13a et 13b présentent plus de deux telles arêtes de coupe, par exemple si le coin antérieur secondaire 131 était tronqué . Les arêtes montantes secondaires antérieures 131A, 141A, 151A et 161A déterminent donc un angle de conicité supérieur à celui de la partie postérieure 1B et donc aussi des quatre arêtes montantes principales antérieures 130A, 140A, 150A et 160A. De ce fait, la partie antérieure 1A ne présente pas exactement la forme d'un tronçon de pyramide, mais est formée par la réunion de deux tronçons de pyramides imbriquées, à conicités différentes. Il va maintenant être précisé, en référence à la figure 2, le détail de la forme du flanc avant 3, constitué par une surface latérale avant antérieure 3A, limitant la partie antérieure 1A, et par la surface latérale avant postérieure 3B, limitant la partie postérieure 1B, l'explication étant transposable pour les trois autres flancs 4 à 6. Dans cet exemple, la surface latérale avant antérieure 3A, définissant un tronçon du bourrelet, est constituée des deux surfaces latérales planes antérieures successives 3a et 3b, mutuellement inclinées, respectivement limitées par les arêtes de coupe 13a et 13b et séparées par l'arête montante secondaire antérieure 131. Le trièdre ainsi formé constitue un bec latéral de coupe. Les flancs 4 à 6 présentent de même les paires de segments de coupe homologues 14a et 14b, 15a et 15b ainsi que 16a et 16b. Ainsi, partant des segments 13a et 13b, les surfaces latérales antérieures 3a et 3b viennent couper la surface latérale postérieure 3B selon deux droites respectives 13c et 13d en V ouvert vers la face antérieure 1. La partie antérieure 1A a donc, dans cet exemple, une épaisseur variable, et en particulier nulle au niveau des coins principaux antérieurs 130, 140, 150 et 160, où le bourrelet s'annule localement. Sur l'épaisseur du pourtour total de la grande face antérieure 1, le bourrelet forme ainsi quatre festons, chacun en forme de bec présentant une extension de débordement latéral et une épaisseur qui sont maximales au niveau des coins secondaires 131, 141, 151 et 161 de pointe de bec, et une épaisseur minimale, ici nulle, au niveau des coins principaux 130, 140, 150 et 160 où ils se raccordent. L'épaisseur courante des quatre becs sur le pourtour total définit une épaisseur fonctionnelle de la partie antérieure 1A, et, par différence avec l'épaisseur totale constante de la plaquette 10, détermine une épaisseur fonctionnelle de la partie postérieure 1B . Dans une autre exemple, il peut être prévu que les coins principaux antérieurs 130, 140, 150 et 160 ne constituent pas le prolongement des arêtes montantes de la pyramide de partie postérieure 1B, c'est-à-dire que les arêtes montantes principales antérieures 130A, 140A, 150A et 160A présentent une conicité indépendante de celle de la partie postérieure 1B, par exemple égale à celle des arêtes montantes secondaires antérieures 131A, 141A, 151A et 161A, pour définir effectivement un tronc de pyramide, ou bien différente pour que le bourrelet offre un support optimal sur toute la longueur des huit segments 13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b, tout en présentant un angle de dépouille voulu. En pareil cas, le minimum d'épaisseur que présente le bourrelet, aux coins principaux 130, 140, 150 et 160, n'est pas nul. Toujours en variante, la partie de couche postérieure 1B pourrait former une semelle d'épaisseur constante, c'est-à-dire que le V de débordement ne formerait plus un trièdre, mais conserverait sa forme sur toute l'épaisseur de la partie antérieure 1A. La paroi latérale arrière radiale 35 du logement 30 présente une forme adaptée, ici plane, pour recevoir en appui tout aussi bien la surface latérale avant postérieure 3B qu'une surface latérale arrière postérieure homologue et de même forme, appartenant au flanc arrière 5, ce qui est le cas de la figure 1. De même, la paroi latérale longitudinale 34 présente le même genre de forme, adaptée pour coopérer avec l'une quelconque des parties postérieures 4B et 6B des flancs 4 et 6. Ainsi, les parois 34 et 35 s'étendent, sensiblement axialement et approximativement radialement, de façon rectiligne, conformément aux deux flancs postérieurs considérés 4B et 5B ou 6B et 3B, d'appui et de cadrage de la pyramide postérieure . De ce fait, une arête montante postérieure issue du coin principal 140, homologue de l'arête montante postérieure 160B issue du coin principal 160, constitue une sorte de dent présentant une bonne extension radiale par rapport à l'axe du trou de fixation 90, et elle offre ainsi une surface moins inclinée sur un rayon de l'axe du trou 90 que ne le serait une dent définie par deux surfaces mutuellement inclinées à 90 degrés. Les deux flancs postérieurs alors considérés, 4B et 5B ou 6B et 3B, présentent donc chacun, en réaction à des forces de couple parasite dans un sens ou dans l'autre, une force essentiellement circonférentielle, ce qui limite l'effet de coin évoqué tout au début . En outre, les parois 34 et 35 peuvent aussi, comme l'évoque la figure 1, être prévues, pour comporter chacune, en partie haute du logement 30, une zone présentant une forme de cavité en V rentrant afin de fournir un complément de force d'appui par coopération avec les zones de flanc antérieures 4A et 5A ou 6A et 3A, même si ce complément est moins efficace que pour la partie postérieure 1B, à flancs rectilignes. • belonging to the respective flanks 3, 4, 5, 6 and limiting the posterior part 1B. The above angles of 75 and 105 degrees, between the overall directions of extension of the cutting edges 13 to 16 are found similarly at the periphery of the posterior face 2 and therefore also at any cutting, parallel to that -ci, lateral surfaces of posterior flank 3B, 4B, 5B and 6B. The preferred angular range mentioned above can however be slightly modified by a different definition, more in line with the definition of the angle of inclination between two surfaces, by considering for this purpose a cutting plane which is exactly perpendicular to the two lateral faces. successive posterior cuts, like 3B and 4B, that is to say a cutting plane which, because of the taper, is found to be slightly inclined with respect to the large faces 1 and 2. In this example, the extensions of the edges rear risers 130B, 140B, 150B and 160B pass through the front main corners 130, 140, 150, 160. Because, in the front face 1A, the segments 13a and 13b, 14a and 14b, 15a and 15b, as well as 16a and 16b, extend laterally outward relative to the parallelogram defined by the four main front corners 130, 140, 150 and 160, it follows that the front part 1A has, around the extension fictitious ment of the pyramidal shape of the rear part 1B, a bead or skirt of material supporting the eight cutting segments above. The front part 1A is substantially in the form of a truncated pyramid with eight sides, the base of which is limited by the four pairs of segments 13a and '13b, 14a and 14b, 15a and 15b, 16a and 16b, and which rise by presenting four so-called main anterior rising edges 130A, 140A, 150A and 160B which are here the extension of the posterior rising edges 130B, 140B, 150B and 160B, as mentioned above. In addition, four so-called secondary front edges 131A, 141A, 151A and 161A rise from four so-called secondary front corners 131, 141, 151, 161 determined by the point of the V of each pair of segments 13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b. It is thus delimited, in the flanks 3 to 6, four anterior flank zones 3A, 4A, 5A and 6A, each comprising two successive surfaces of different orientations, 3a and 3b, 4a and 4b, 5a and 5b, 6a and 6b , respectively located under the two segments considered. Each edge such as for example the edge formed by the segments 13a and 13b is thus supported by two surfaces forming a beak, that is to say a kind of cornice with lateral extension, constituting a projection of the profile, in front view. , of the anterior face 1. In addition, the secondary edges such as the edge 131A, for example, have here an extension limited to less than half, here about a third, of the thickness of the plate 10, so that 'They extend at a relatively high angle, for example greater than 30 degrees, here about 45 degrees, relative to the associated side face 3B or the like. The corresponding side face 3B can thus be further back from a workpiece, thus offering an increased volume of chip clearance. Alternatively, provision could be made for the spouts like 13a and 13b to have more than two such cutting edges, for example if the secondary front corner 131 was truncated. The anterior secondary rising edges 131A, 141A, 151A and 161A therefore determine a taper angle greater than that of the posterior part 1B and therefore also of the four main front rising edges 130A, 140A, 150A and 160A. Therefore, the front part 1A does not have exactly the shape of a segment of pyramid, but is formed by the union of two sections of overlapping pyramids, with different conicities. It will now be specified, with reference to FIG. 2, the detail of the shape of the front flank 3, constituted by a front anterior lateral surface 3A, limiting the front part 1A, and by the rear front side surface 3B, limiting the part posterior 1B, the explanation being transposable for the other three flanks 4 to 6. In this example, the front anterior lateral surface 3A, defining a section of the bead, consists of the two successive anterior flat lateral surfaces 3a and 3b, mutually inclined, respectively limited by the cutting edges 13a and 13b and separated by the anterior secondary rising edge 131. The trihedral thus formed constitutes a lateral cutting beak. The flanks 4 to 6 likewise have the pairs of homologous cutting segments 14a and 14b, 15a and 15b as well as 16a and 16b. Thus, starting from the segments 13a and 13b, the anterior lateral surfaces 3a and 3b come to cut the posterior lateral surface 3B along two respective straight lines 13c and 13d in V open towards the anterior face 1. The anterior part 1A has therefore, in this example, a variable thickness, and in particular zero at the level of the front main corners 130, 140, 150 and 160, where the bead cancels locally. Over the thickness of the total periphery of the large anterior face 1, the bead thus forms four festoons, each in the form of a beak having a lateral overflow extension and a thickness which are maximum at the level of the secondary corners 131, 141, 151 and 161 of the beak point, and a minimum thickness, here zero, at the level of the main corners 130, 140, 150 and 160 where they are connected. The current thickness of the four nozzles on the total periphery defines a functional thickness of the front part 1A, and, by difference with the constant total thickness of the plate 10, determines a functional thickness of the rear part 1B. In another example, it can be provided that the front main corners 130, 140, 150 and 160 do not constitute the extension of the rising edges of the rear part pyramid 1B, that is to say that the front main rising edges 130A, 140A, 150A and 160A have a conicity independent of that of the posterior part 1B, for example equal to that of the anterior secondary rising edges 131A, 141A, 151A and 161A, to effectively define a trunk of the pyramid, or else so that the bead provides optimal support over the entire length of the eight segments 13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b, while having a desired draft angle. In such a case, the minimum thickness presented by the bead, at the main corners 130, 140, 150 and 160, is not zero. Still alternatively, the posterior layer part 1B could form a sole of constant thickness, that is to say that the overflow V would no longer form a trihedron, but would retain its shape over the entire thickness of the anterior part. 1A. The radial rear side wall 35 of the housing 30 has a suitable shape, here flat, to receive as much support the front rear side surface 3B as a homologous rear rear side surface of similar shape and belonging to the rear flank 5, this who is the case of Figure 1. Similarly, the longitudinal side wall 34 has the same kind of shape, adapted to cooperate with any of the rear parts 4B and 6B of the sides 4 and 6. Thus, the walls 34 and 35 s 'extend, substantially axially and approximately radially, in a rectilinear manner, in accordance with the two posterior flanks considered 4B and 5B or 6B and 3B, of support and framing of the posterior pyramid. As a result, a posterior rising edge coming from the main corner 140, homologous with the posterior rising edge 160B coming from the main corner 160, constitutes a kind of tooth having a good radial extension with respect to the axis of the fixing hole 90, and it thus offers a surface less inclined on a radius of the axis of the hole 90 than would be a tooth defined by two surfaces mutually inclined at 90 degrees. The two posterior flanks then considered, 4B and 5B or 6B and 3B, therefore each present, in response to parasitic torque forces in one direction or the other, an essentially circumferential force, which limits the corner effect mentioned. at the very beginning. In addition, the walls 34 and 35 may also, as shown in FIG. 1, be provided, to each comprise, in the upper part of the housing 30, an area having a shape of a recessed V-shaped cavity in order to provide additional force. support by cooperation with the anterior flank zones 4A and 5A or 6A and 3A, even if this complement is less effective than for the posterior part 1B, with rectilinear flanks.

Claims

Revendications claims
1. Plaquette de coupe réversible comportant une partie de couche antérieure (1A) , de tête de coupe, comportant des faces latérales de pourtour antérieur (3A, 4A, 5A, 6A) mutuellement inclinées et délimitant, avec une grande face antérieure (1) , un profil de vue avant formé par un certain nombre d'arêtes de coupe (13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b) mutuellement inclinées selon le dit profil, et une partie de couche postérieure (1B) , constituant une base d'ancrage sur un porte-outil, comportant des faces latérales de pourtour postérieur dont au moins certaines sont des faces d'appui de cadrage (3B, 4B, 5B, 6B) sur des parois d'un logement (30) du porte- outil, caractérisée par le fait que le pourtour postérieur comporte un nombre de faces latérales d'appui de cadrage (3B, 4B, 5B, 6B) inférieur au nombre d'arêtes de coupe (13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b) . 1. Reversible cutting insert comprising a part of anterior layer (1A), of cutting head, comprising lateral faces of anterior periphery (3A, 4A, 5A, 6A) mutually inclined and delimiting, with a large anterior face (1) , a front view profile formed by a certain number of cutting edges (13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b) mutually inclined according to said profile, and a portion of posterior layer (1B), constituting an anchoring base on a tool holder, comprising lateral rear periphery faces at least some of which are framing bearing faces (3B, 4B, 5B, 6B) on the walls of a housing (30) of the tool holder, characterized in that the rear periphery comprises a number of lateral framing support faces (3B, 4B, 5B, 6B) less than the number of cutting edges (13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b).
2. Plaquette selon la revendication 1, dans laquelle les faces latérales d'appui de cadrage (3B, 4B, 5B, 6B) sont planes . 2. Plate according to claim 1, in which the lateral framing support faces (3B, 4B, 5B, 6B) are plane.
3. Plaquette selon la revendication 1, dans laquelle les faces latérales d'appui de cadrage (3B, 4B, 5B, 6B) définissent un dit pourtour postérieur courbe. 3. Plate according to claim 1, wherein the lateral framing support faces (3B, 4B, 5B, 6B) define a said curved posterior periphery.
4. Plaquette selon la revendication 3, dans laquelle la courbure est variable sur une même face latérale d'appui de cadrage (3B) . 4. Plate according to claim 3, wherein the curvature is variable on the same side face of framing support (3B).
5. Plaquette selon l'une des revendications 1 à 4, dans laquelle les faces latérales successives d'appui de cadrage (3B, 4B, 5B, 6B) se raccordent selon des angles respectifs inférieurs à 180 degrés, pour ainsi définir un dit pourtour postérieur à orientation variant de façon monotone . 5. Plate according to one of claims 1 to 4, in which the successive lateral faces of framing support (3B, 4B, 5B, 6B) are connected at respective angles less than 180 degrees, thereby defining a said posterior periphery with orientation varying monotonously.
6. Plaquette selon l'une des revendications 3 à 5, dans laquelle les faces latérales d'appui de cadrage (3B, 4B, 5B, 6B) sont concaves. 6. Plate according to one of claims 3 to 5, wherein the lateral framing support faces (3B, 4B, 5B, 6B) are concave.
7. Plaquette selon 1 '-une des revendications 1 à 6, dans laquelle les faces latérales d'appui de cadrage (3B, 4B, 5B, 6B) sont globalement tronconiques . 7. Plate according to one of claims 1 to 6, in which the lateral framing support faces (3B, 4B, 5B, 6B) are generally frustoconical.
8. Plaquette selon la revendication 7, dans laquelle la partie de couche antérieure (1A) présente une forme de tronc de pyramide présentant des arêtes montantes (130A, 140A, 150A, 160A) alignées avec des arêtes montantes (130B, 140B, 150B, 160B) de la partie de couche postérieure (1B) . 8. The plate as claimed in claim 7, in which the front layer part (1A) has the shape of a pyramid trunk having rising edges (130A, 140A, 150A, 160A) aligned with rising edges (130B, 140B, 150B, 160B) of the posterior layer part (1B).
9. Plaquette selon l'une des revendications 1 à 8, dans laquelle la partie de couche antérieure (1A) est délimitée par deux tronçons de pyramides imbriquées, à conicités différentes. 9. Plate according to one of claims 1 to 8, in which the part of the anterior layer (1A) is delimited by two sections of overlapping pyramids, with different conicities.
10. Plaquette selon l'une des revendications 1 à 9, dans laquelle la grande face antérieure (1) présente globalement une forme de parallélogramme. 10. Plate according to one of claims 1 to 9, wherein the large front face (1) generally has a shape of parallelogram.
11. Plaquette selon la revendication 10, dans laquelle certaines, parmi des paires de faces latérales d'appui de cadrage consécutives (3B, 4B, 5B, 6B) , sont mutuellement inclinées d'un angle compris entre 65 et 85 degrés. 11. Plate according to claim 10, in which some, among pairs of lateral faces of consecutive framing support (3B, 4B, 5B, 6B), are mutually inclined at an angle between 65 and 85 degrees.
12. Porte-outil pour une plaquette de coupe (10) selon l'une des revendications 1 à 11, comportant un logement (30) comprenant un fond (32), associé à des moyens (31, 41) de bridage de la plaquette, et des parois latérales (34, 35) de réception de flancs postérieurs (3B, 4B, 5B, 6B) d'appui de cadrage de la plaquette, caractérisé par le fait que le logement (30) est agencé pour recevoir en appui un premier nombre déterminé de flancs postérieurs (3B, 4B, 5B, 6B) d'appui de cadrage de la plaquette et pour laisser accessibles un second nombre déterminé, supérieur au premier nombre, d'arêtes de coupe antérieures de la plaquette (13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b) , déterminées par autant de faces latérales de pourtour antérieur mutuellement inclinées. 12. Tool holder for a cutting insert (10) according to one of claims 1 to 11, comprising a housing (30) comprising a bottom (32), associated with means (31, 41) for clamping the insert , and side walls (34, 35) for receiving rear flanks (3B, 4B, 5B, 6B) for framing the wafer, characterized in that the housing (30) is designed to receive in support a first determined number of posterior flanks (3B, 4B, 5B, 6B) for framing the wafer and for leaving a second determined number, greater than the first number, accessible from the front cutting edges of the wafer (13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b) , determined by as many lateral faces of mutually inclined anterior periphery.
13. Porte-outil selon la revendication 12, dans lequel les parois (34, 35) du logement sont évasées par rapport au fond (32) . 13. Tool holder according to claim 12, wherein the walls (34, 35) of the housing are flared relative to the bottom (32).
14. Porte-outil selon l'une des revendications 12 et 13, dans lequel les parois (34, 35) du logement sont mutuellement inclinées d'un angle situé dans une plage allant de 65 à 85 degrés. 14. Tool holder according to one of claims 12 and 13, wherein the walls (34, 35) of the housing are mutually inclined at an angle in a range from 65 to 85 degrees.
15. Porte-outil selon l'une des revendications 12 à 14, dans lequel les parois (34, 35) du logement sont en outre adaptées pour recevoir, en appui de cadrage, des flancs antérieurs (3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b) de support des arêtes de coupe antérieures de la plaquette (13a et 13b, 14a et 14b, 15a et 15b, 16a et 16b) . 15. Tool holder according to one of claims 12 to 14, wherein the walls (34, 35) of the housing are further adapted to receive, in framing support, front flanks (3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b) for supporting the anterior cutting edges of the insert (13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b).
EP05732915A 2004-02-25 2005-02-25 Cutting insert having a limited number of frame faces Withdrawn EP1737597A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0401877A FR2866583B1 (en) 2004-02-25 2004-02-25 CUTTING PLATE WITH A LIMITED NUMBER OF FRAMES OF FRAMING
PCT/FR2005/000454 WO2005089994A1 (en) 2004-02-25 2005-02-25 Cutting insert having a limited number of frame faces

Publications (1)

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EP1737597A1 true EP1737597A1 (en) 2007-01-03

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US (1) US7604440B2 (en)
EP (1) EP1737597A1 (en)
FR (1) FR2866583B1 (en)
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Also Published As

Publication number Publication date
FR2866583B1 (en) 2007-04-20
US20070217875A1 (en) 2007-09-20
FR2866583A1 (en) 2005-08-26
US7604440B2 (en) 2009-10-20
WO2005089994A1 (en) 2005-09-29

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