Classifications

• • 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
  • 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
  • B23C5/202—Plate-like cutting inserts with special form
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2200/00—Details of milling cutting inserts
  • B23C2200/04—Overall shape
  • B23C2200/0416—Irregular
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2200/00—Details of milling cutting inserts
  • B23C2200/08—Rake or top surfaces
  • B23C2200/085—Rake or top surfaces discontinuous
• • 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
  • B23C2200/00—Details of milling cutting inserts
  • B23C2200/20—Top or side views of the cutting edge
  • B23C2200/203—Curved cutting edges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2200/00—Details of milling cutting inserts
  • B23C2200/36—Other features of the milling insert not covered by B23C2200/04 - B23C2200/32
  • B23C2200/367—Mounted tangentially, i.e. where the rake face is not the face with largest area
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2250/00—Compensating adverse effects during milling
  • B23C2250/16—Damping vibrations

Definitions

• the invention relates to a cutting plate with a base in each case in opposite plate planes of a base body and with at least one side surface. It also relates to a milling tool with such a cutting insert.
• cutting insert is understood to mean, in particular, an indexable insert and, in particular, a milling cutter is a finishing cutter.
• the cutting or indexable inserts that are usually used essentially have two opposing base surfaces, which are used both as contact surfaces and as free surfaces for the main cutting edge in use.
• four planar surfaces are arranged on the circumference
• this can also have a circular or ellipsoidal curvature.
• the curvature increases evenly starting from the center of the cutting edge in the direction of the two cutting edge ends.
• such a cutting edge which is circular or ellipsoidal with respect to the surface to be machined, in turn causes undesirable small error tolerances in relation to angular errors with increasing cutting body radius due to the uniformly or uniformly increasing curvature values starting from the center of the cutting edge in the direction of the two cutting edge ends.
• the deterioration of the surface quality with a decreasing radius of the cutting edge is particularly disadvantageous.
• the cutting or indexable insert can be fixed in the carrier while the position of the cutting edge relative to the surface cannot be changed, or it can be connected to the carrier in such a way that a subsequent displacement of the cutting edge with respect to the surface to be machined is possible.
• a disadvantage of fixing the insert with an unchangeable cutting edge position is the requirement for a very precise tool carrier for the insert.
• an increased susceptibility of the overall system with respect to a change in position of the cutting edge due to external influences is disadvantageous in the case of a cutting insert connection with subsequent displacement of the cutting edge.
• the invention is based on the object of specifying a cutting insert, in particular an indexable insert, which, while avoiding the disadvantages mentioned, enables a particularly high surface quality of the workpiece to be machined. Furthermore, a milling tool, in particular a finishing cutter with such a Cutting plate are specified with which the smallest possible shaft or profile depths in the workpiece to be machined and thus a particularly smooth surface is achieved. In particular, the requirements mentioned above with regard to the surface quality of the surface to be machined should be met.
• the cutting plate has at least one side surface with a conical surface section and with a planar surface section.
• the conical surface section and the base surface facing it form an acute angle to one another, forming a cutting edge, while the planar surface section forms an obtuse angle with the opposite base surface.
• the cone-shaped surface section lifts up from the side surface to form an eccentric arc-shaped course of the cut edge, in that the cone axis of this cone-shaped surface section lying in the plane of the plate and thus in the plane of the base surface runs parallel to the central plate axis lying in the same plate plane.
• the axis of the conical surface section is offset from the central axis of the insert.
• the conical section resulting from this off-center spherical surface section represents an ellipse with two cutting edge segments of different lengths with respect to the surface to be machined, each measured from the cone axis to one or the other cutting edge end.
• the meeting point - and thus the vertex of the elliptical cutting edge - of both segments represents the highest point.
• the vertex lies exactly below that in the plate plane, i.e. in the plane of the base surface of the cone axis of the conical surface section or the conical surface.
• the radius of curvature is very large in relation to the arc length of the cutting edge, i.e. practically hardly visible.
• the curve of the cutting edge expediently lies in the plane of the base area.
• a cutting insert the rake face of which consists of a convexly curved surface area and a planar surface section, is known from DE 4446 824 A1 known.
• the curvature of the convex surface section is set in such a way that the distance between the cutting edge and an imaginary line connecting its end points is maximum in the center of the cutting edge.
• the cutting edge is approximately symmetrically curved with respect to its end points.
• the curved cutting edge of the known cutting plate does not otherwise serve to produce a smooth workpiece surface, especially since the known cutting plate is attached to the circumference of the milling tool, and the main cutting edge is thus not aligned parallel to the flat surface of the workpiece.
• a short secondary cutting edge is used to smooth the workpiece surface.
• the cutting plate has at least one expediently wedge-shaped corner chamfer surface. This forms an obtuse angle both with the conical surface section and with the planar surface section and with the base surface facing away from the cutting edge.
• a wedge-shaped corner chamfer surface advantageously achieves a soft gate on the one hand and a shortening of the opposite cutting edge on the other hand is avoided.
• the conical surface section and the planar surface section are arranged at different angles, a cutting edge formed by these two surface sections facing the cutting edge at the apex of the latter.
• the insert is designed as an indexable insert with four side surfaces of this type, the conical surface sections and the planar surface sections of opposite side surfaces being inclined towards one another, i.e. are inclined towards each other.
• This indexable insert advantageously has two corner chamfer surfaces arranged symmetrically to each base surface.
• each corner chamfer surface forms an obtuse angle with one of the base surfaces and one of the side surfaces, while this corner chamfer surface forms a cone-shaped surface Surface portion of the adjacent side surface forms an ellipsoidal edge at an acute angle.
• the indexable insert is also characterized by a rhombus-shaped base body, whose opposing base surfaces are rotated relative to one another by an angle of (97 ⁇ 2) °, preferably 97 °.
• the milling tool according to the invention has a number of such cutting plates, which are arranged on a tool carrier in the region of its finishing knife head, distributed around the circumference.
• the preferably double-sided indexable inserts are connected to the tool holder in such a way that the cutting edge of the respective insert is fixed in the intended position, so that subsequent displacement of the cutting edge is no longer possible.
• the cutting plate provided on the circumferential region of the 0 ° center line of the tool holder is expediently offset from this center line by an angle of (5 ⁇ 3) °.
• each insert seat in the tool holder assigned to an insert has, in addition to a support surface facing the respective base surface of the insert and a contact surface facing the respective side surface of the insert, a receiving opening for receiving a stop pin, which serves as an axial stop for the insert. Due to the fact that this stop pin is only installed after the machining of the insert seat, the support surface and the contact surface of the insert seat can be processed simultaneously in one work step. This makes it possible to produce a runout accuracy of 10 ⁇ m in the tool carrier.
• the advantages achieved by the invention consist primarily in the combination of the off-center cone of the conical surface section of the respective side surface of the cutting insert - and thus by the curved cutting edge with a decentralized curvature maximum or apex - and the arrangement of the cutting insert within the tool holder whose 0 ° center line results in a particularly high surface quality of the surface of a workpiece to be machined as a result of an increased radius caused thereby.
• a tool used as a finishing cutter can be reduced by a factor of 2 remaining shaft or profile depths than with surfaces machined with previous finishing cutters.
• FIG. 1 is a perspective view of a cutting insert according to the invention with a side surface having an asymmetrical conical and planar surface section,
• FIG. 2 in a representation according to FIG. 1 designed as an indexable insert
• FIG. 3 the cutting plate according to FIG. 2 in a plan view
• FIG. 4 the cutting plate in a side view
• FIG. 5 in perspective view a milling tool with a plurality of such cutting plates
• FIG. 6 the milling tool in a plan view .
• Fig. 7 is a sectional view of the milling tool along the line Vll-Vll in Fig. 6,
• Fig. 8 shows a section VIII of Fig. 6 on a larger scale, and
• Fig. 9 in a section according to Fig. 8 a plate seat in the tool holder cutter head of milling tool.
• the insert 1 shown in FIG. 1 comprises a base body 2 with two base surfaces 3, which are located in opposing insert planes E1 and E2.
• the cutting insert 1 also has a side surface 4 with a conical surface section 4a and a planar surface section 4b.
• the cone-shaped surface section 4a and the base surface 3 facing it are at an acute angle ⁇ (FIG. 4) and form a cutting edge 5.
• the planar surface section 4b forms an obtuse angle ⁇ with the opposite base surface 3 (FIG. 4).
• the cutting edge 5 has an arc running in the plane E1 of the base 3 with an eccentric - and thus asymmetrical - curvature of the cone-shaped surface section 4a.
• the cone axis 6 of the cone-shaped surface section 4a lying in the plate plane E1 runs parallel to the central plate axis 7 lying in the same plate plane E1, forming the eccentric arcuate shape of the cutting edge 5 at a distance d.
• FIG. 2 shows a cutting plate which acts as an indexable insert or indexable insert 1 'and has four such side faces 4, of which only two side faces 4 are visible.
• the indexable insert 1 ' has a rhombus-shaped base body 2 with four cutting edges 5.
• the geometric shape and the dimensions of the two base areas 3 are at least almost identical, but rotated by 97 ° with respect to one another.
• the indexable insert 1 'thus has four planar surface sections 4b and four cone-shaped surface sections or conical surface areas 4a.
• a planar surface section 4b and a cone-shaped surface section 4a each represent a side surface 4 of the base body 2.
• Cone-shaped surface sections 4a lying opposite each other form an acute angle ⁇ with one of the base surfaces 3 (FIG. 4).
• the resulting conic sections represent the cutting edges 5, which are consequently also opposite. With the respective other base area 3, the cone-shaped surface sections 4a have no cutting line.
• the respectively opposite planar surface sections 4b of the side surfaces 4 form an obtuse angle ⁇ with the base surface 3 (FIG. 4), the resulting edge 8 not being a cutting edge. With the respective other base area 3, these planar surface sections 4b have no common edge.
• the respectively opposite planar surface sections 4b and the opposite cone-shaped surface sections 4a of the respective side surface 4 are inclined towards one another. 1 has a corner chamfer surface 9, four such corner chamfer surfaces 9 are provided in the indexable insert V according to FIG. 2. Two of these corner chamfer surfaces 9 are each arranged symmetrically distributed with respect to each of the base surfaces 3.
• the corner chamfer surface 9 is in each case spanned between a base surface 3 and a planar surface section 4b.
• the respective corner chamfer surface 9 forms an obtuse angle with the base surface 3 and with a conical surface section 4a and a planar surface section 4b, while this corner chamfer surface 9 forms an acute angle with the other, not opposite, conical surface section 4a.
• a resulting edge 10 is ellipsoidal and is used in particular as a corner or chamfer phase.
• the respective cone axis 6 also has an offset with respect to the central insert axis 7 of the insert 1 'in the double-sided insert 1'.
• the resulting conic section represents an ellipse with edge segments 5a and 5b of the cutting edge 5 with respect to the surface of a workpiece to be machined.
• the meeting point of both edge segments at the apex 11 (FIGS. 1 and 2) 5a, 5b represent the highest point, the apex 11 lying below the cone axis 6 running in the respective plate plane E1, E2 of the base surface 3 (FIG. 1). Due to the very large radius of curvature in relation to the arc length of the cutting edge 5, this arcuate course of the cutting edge 5 or its curvature is practically not visible in the illustrations.
• the angle difference is chosen such that the cutting edge 14 (FIG. 4) resulting from the intersection of the two surface sections 4a, 4b faces the respective cutting edge 5 with its apex 11.
• indexable insert 1 ' Another feature of the indexable insert 1 'is, on the one hand, a different inclination of the circumferentially arranged conical surface sections 4a and the planar surface sections 4b, which are likewise arranged on the circumference, on the other hand with respect to the respective base surface 3.
• the negative inclination angle ⁇ produces a particularly soft gate behavior and promotes radial chip removal.
• the shape of the cutting edge 5 of the double-sided indexable insert 1 ' is optimally adapted to the described geometric conditions with regard to the setting angle ⁇ and the inclination angle ⁇ , so that if the parameters deviate from the values mentioned, the surface image and the surface parameters of the surface to be machined deteriorate O is to be expected.
• a continuous circular opening 15 which is used for particularly simple mounting in a tool holder 16 (FIG. 5) by means of a clamping bolt and screw fastening.
• the design of the base body 2 thus creates a cutting or indexable insert 1 or 1 'which fulfills the requirement for a particularly smooth and in particular groove-free and groove-free surface.
• the design of the outer shape of the cutting plate 1, V in the form shown ensures line contact between this cutting plate 1, 1 'and the plate seat contact surfaces of the tool carrier 16 of a milling tool or finishing cutter 17 described in more detail with reference to the following FIGS. 5 to 9.
• the value of the setting angle ⁇ is largely determined by the shape of the bevel of the surface sections 4a, 4b of the cutting plate 1 'and thus by the shape of the cutting edge 5.
• the setting angle ⁇ can also vary with different forms of this bevel.
• the finishing cutter 17 ' provided with a plurality of indexable inserts 1' distributed around the circumference of the cutter head 16 of the tool carrier 16 has between adjacent indexable inserts 1 'chip troughs 18 for the removal of chip arising during the machining of a workpiece or a surface O.
• the indexable insert V provided in the region of the center line M of the tool carrier 16 is arranged in such a way that it is offset in the milling tool 17 by an offset angle ⁇ of ⁇ equal to (5 ⁇ 3) ° in front of the center line M.
• ⁇ of ⁇ equal to (5 ⁇ 3) ° in front of the center line M.
• the four circumferential cone-shaped surface sections per indexable insert 1 ', the convex curvature of which produce the curvature of the cutting edge 5, form the rake face of the main cutting edge and partially the free surface of the secondary cutting edge.
• these cone-shaped surface sections 4a have no function as a contact surface in the plate seat 20 shown in FIG. 9.
• the position of the cutting edge 5 in relation to the surface O to be machined is essentially determined in the tool carrier 16 by the position of the insert seat 20 to the contact surface 21 and the receiving bore 22 of the tool carrier 16 (FIG. 7).
• Another determining factor is the geometrical accuracy of the reference surfaces, i.e. the contact surface 23 facing the respective base surface 3 and the contact surface 24 of the plate seat 20 facing the respective side surface 4.
• the geometric shape of the plate seat 20 and the accuracy with regard to manufacture are adapted to the smallest possible deviation of the geometric parameters.
• a hardened steel pin 25 is used as an axial stop for the indexable insert 1 'in the insert seat 20 shown.
• the plate seat 20 is provided in the area of the support surface 23 with a corresponding receiving opening 26 for this stop pin 25.
• the stop pin 25 is only mounted after the machining of the support or base surface 23 and the radial contact surface 24.
• the design enables the machining of both the contact surface 23 and the radial contact surface 24 in a single machining step. This procedure ensures that a run-out accuracy of 10 ⁇ m can be generated in the tool carrier 16.
• the concentricity of the indexable inserts 1 'to the axis of rotation 27 (FIG. 7) of the milling tool 17 is largely determined by the axial position of the hardened contact pin 25.
• the deviation from the axis of rotation 27 should be as small as possible.
• the tool carrier 16 has threaded bores 29 arranged on the circumference on the tool collar 28, into which threaded pins 30 of different lengths made of steel, in particular, can be screwed if necessary.
• the milling tool 17 can be set to a residual unbalance of G 6.3 at 10,000 revolutions per minute (1 / min).
• a further improvement in the surface quality can be achieved by reducing oscillations and vibrations during processing. These vibrations can be kept low by reducing the unbalance of the milling tool 17.
• This inevitably leads to a reduction in the free mass forces and thus a reduction in the deflections of the tool under their influence.
• This in turn has a positive effect on the quality and quality of the machined surface O and leads to a particularly low load on the drive spindle of the milling machine on which the milling tool 17 is used.
• the milling cutter or finishing cutter head of the tool carrier 16 with the double-sided indexable inserts V, each with four cutting edges 5 for finishing, has fixed-position indexable inserts V, the position of the cutting edges 5 relative to the surface O being no longer changeable after fixing.
• the respective indexable insert 1 ' is connected to the tool carrier 16 in such a way that the cutting edge 5 of the indexable insert 1' is fixed in a suitable manner in the predetermined position, so that a subsequent displacement of the cutting edge 5 is no longer possible. This practically precludes a shift in the position of the indexable insert V with respect to the tool carrier 16 due to external influences.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Milling Processes (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Related Child Applications (1)

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Citations (6)

• 2002
  • 2002-09-05 JP JP2003526612A patent/JP2005501748A/ja active Pending
  • 2002-09-05 CN CN02819853.0A patent/CN1564723A/zh active Pending
  • 2002-09-05 WO PCT/EP2002/009938 patent/WO2003022496A1/de not_active Application Discontinuation
  • 2002-09-05 EP EP02774569A patent/EP1436111A1/de not_active Ceased

Patent Citations (6)

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