JP6419453B2 - Cutting tool and method of manufacturing cutting tool - Google Patents

Description

  The present invention relates to a cutting tool for trim processing.

  Since fiber reinforced resin (FRP) is lightweight and has high strength, it is frequently used in aircraft and the like. Since this FRP has a higher viscosity than ordinary steel materials, it is easy to weld, and the contained carbon and glass fibers also exhibit difficult cutting properties, so that the cutting resistance during processing is large.

  As a tool for cutting such an FRP material, there is a cutting tool having a diamond structure (for example, Patent Document 1). A cutting tool having such a diamond structure is different from a normal square end mill and the like in that there are few cutting blades hitting the work material, so that the cutting resistance can be reduced.

Japanese Patent Laid-Open No. 02-131810

  FIG. 11 is a perspective view showing a cutting tool 100 having a conventional diamond structure, and FIG. 12 is a side view.

  As shown in FIG. 12, the cutting tool 100 includes a blade portion 101a on the distal end side and a shank 101b on the base portion side. The blade portion 101a is formed with a right twist blade groove 107 and a left twist blade groove 109 at a predetermined angle with respect to the axis. The right twist blade groove 107 and the left twist blade groove 109 are formed so as to be twisted in opposite directions with respect to the axis.

  A portion surrounded by the right helix blade groove 107 and the left helix blade groove 109 is the cutting edge portion 103. That is, a plurality of cutting edge portions 103 are provided along the right twisting blade groove 107 and the left twisting blade groove 109.

  Fig.13 (a) is the V section enlarged view of FIG. The cutting edge portion 103 has a substantially quadrangular pyramid shape. The front end side surface of the cutting edge portion 103 is a rake face 111 and the top portion is a cutting edge 113.

  FIG.13 (b) is a schematic diagram which shows the cross section of the cutting blade part 103 on the W line | wire of FIG. That is, FIG. 13B is a cross-sectional view taken along a line parallel to the right twisted blade groove 107 and passing through the apex of the cutting edge portion 103 (cutting edge 113). Usually, a surface coating 119 is formed on the surface of the cutting tool 100 in order to increase the edge strength. The surface coating is a hard layer such as a diamond coat.

  However, as described above, the cutting edge portion 103 has a substantially quadrangular pyramid shape, and the apex cutting edge 113 is pointed. For this reason, there exists a problem that the surface coating coat | covered by this vicinity tends to peel in the early stage of cutting.

  Further, when the cutting tool is rotated and brought into contact with the work material, the cutting tool (cutting edge portion 103) applies force to the work material in two directions. That is, the cutting force in two directions is received from the work material. If this cutting resistance becomes too large, vibration will increase, causing problems such as deterioration of surface quality and breakage of the cutting edge portion 103.

  In particular, when the work size is increased, the fixed state of the work material tends to become unstable, and vibration becomes a big problem.

  The present invention has been devised in view of such problems, and an object thereof is to provide a cutting tool with less vibration.

In order to achieve the above-described object, a first invention is a trimming cutting tool, wherein the cutting tool includes a blade portion and a shank, and the blade portion includes a right twist blade groove and a left twist blade. Each groove is provided with a predetermined twist angle, and includes a plurality of cutting edge portions divided by the right twisting blade groove and the left twisting blade groove, and the plurality of cutting edge portions are uniformly disposed on the blade portion. The plurality of cutting edge portions have a substantially square frustum shape, and a substantially rectangular margin surface is formed at the top, and each of the margin surfaces is formed on the same circumferential surface with the rotation axis of the cutting tool as the center. It is the cutting tool for trim processing characterized by being performed.

  Thus, since the margin surface of the top part of each cutting edge part is formed on the same circumferential surface, the direction of the cutting resistance applied to the cutting edge part can be dispersed. For this reason, vibration can be suppressed and high surface quality can be obtained.

  The margin surface is a substantially parallelogram in plan view from the top side, the length of one set of parallel sides of the margin surface is L1 mm, the length of the other set of parallel sides is L2 mm, It is desirable that the relationship of 2.5 / n ≦ L1 ≦ L2 ≦ 5 / n be satisfied, where n is the number of blade rows arranged in parallel to the right twisted blade groove.

  By making the shape of the cutting edge portion like this, vibration can be suppressed.

  The outer peripheral surface of the cutting tool is preferably provided with a surface coating.

  With the above configuration, the surface hardness and the like of the cutting tool can be increased and the tool life can be further extended. At this time, since the margin surface is formed at the top of the cutting edge portion, peeling of the surface coating can be suppressed.

2nd invention is the manufacturing method of the cutting tool for trim processing which concerns on 1st invention, Comprising: With respect to a column-shaped base material, it is a right twist blade groove | channel with each predetermined twist angle on the side surface of the said base material. And a left twisted blade groove , forming a blade portion composed of a plurality of cutting blade portions divided by the blade groove, and when forming the blade groove, the cutting blade portion has a substantially rectangular margin surface A trimming cutting tool manufacturing method is characterized in that a part of a cylindrical shape of a base material surface is left at the top so as to have a substantially square frustum shape.

  By doing in this way, it is not necessary to grind the front-end | tip of a cutting blade part later, and to form a surface.

  According to the present invention, it is possible to provide a cutting tool with less vibration.

The perspective view of the cutting tool 1. FIG. The side view of the cutting tool 1. FIG. The enlarged view of the cutting blade part 3. FIG. It is a schematic diagram which shows the shape of the cutting blade part 3 on the line parallel to the right twist blade groove | channel 7, (a) is a figure which shows an external shape, (b) is a top view. FIG. 3 is a developed schematic view of the cutting tool 1. Sectional drawing of the cutting blade part 3. FIG. The figure which shows the cutting resistance with the conventional cutting tool which does not have a margin surface. The figure which shows the cutting resistance with the cutting tool whose side length of a margin surface is 0.1 mm. The figure which shows the cutting resistance with the cutting tool whose side length of a margin surface is 0.3 mm. The figure which shows the cutting resistance with the cutting tool whose side length of a margin surface is 0.5 mm. The perspective view of the conventional cutting tool 100. FIG. The side view of the conventional cutting tool 100. FIG. It is a figure which shows the shape of the cutting-blade part 103 of the conventional cutting tool 100, (a) is a perspective view, (b) is sectional drawing.

  Embodiments of the present invention will be described below. FIG. 1 is a perspective view of a cutting tool 1 according to an embodiment of the present invention, and FIG. 2 is a side view. The cutting tool is a tool for trim processing. The cutting tool 1 includes a blade portion 1a and a shank 1b.

  The blade portion 1a is provided with a right twist blade groove 7 and a left twist blade groove 9 having a predetermined angle with respect to the axial direction of the tool. The right twisted blade groove 7 is twisted in the right direction when viewed from the tip side of the tool. The left twisted blade groove 9 is twisted in the left direction when viewed from the tip side of the tool. That is, the right twist blade groove 7 and the left twist blade groove 9 are twisted in opposite directions. It is desirable that the right twist blade groove 7 and the left twist blade groove 9 are formed at the same angle with respect to the axial direction. Here, the range of a preferable twist angle is 15 ° to 35 °, and more preferably 20 ° to 30 °. When the twist angle is less than 15 °, the rigidity of the blade becomes weak and chipping is likely to occur. When the twist angle is 35 ° or more, there is a concern about deterioration of surface quality due to increased vibration.

  A portion surrounded by the right twisted blade groove 7 and the left twisted blade groove 9 is a cutting blade portion 3. That is, the cutting edge portion 3 is provided side by side at a predetermined angle with respect to the axis at substantially the same pitch in the blade portion 1a.

  FIG. 3 is an enlarged view of a portion A in FIG. 2, and is an enlarged perspective view of the cutting edge portion 3. The cutting edge portion 3 has a substantially square frustum shape. In other words, the upper part of the quadrangular pyramid shape is cut off. Therefore, a substantially flat margin surface 5 is formed at the top of the cutting edge portion 3. The margin surface 5 is substantially rectangular.

  In the direction of the cutting edge portion 3 along the right twisted blade groove 7, the concave surface becomes the right twisted blade rake face 13. Further, the concave surface in the direction along the left helix blade groove 9 becomes the left helix blade rake face 11.

  When the right helix blade groove 7 and the left helix blade groove 9 are formed at the same angle (opposite direction with respect to the axis), the margin surface 5 becomes a substantially parallelogram (including a substantially rhombus and a substantially square).

  The side parallel to the right twist blade groove 7 and on the right twist blade rake face 13 side becomes the right twist blade 17. Further, the side parallel to the left twist blade groove 9 and the side on the left twist blade rake face 11 side becomes the left twist blade 15.

  In addition, the cutting tool 1 is manufactured as follows, for example. A right twisted blade groove 7 and a left twisted blade groove 9 are formed on a round bar as a material. At this time, a part of the outer peripheral surface of the cylindrical shape is left at the top of the cutting edge portion 3 formed by the right twisted blade groove 7 and the left twisted blade groove 9. That is, the margin surface 5 is a portion where the outer peripheral surface of the original material remains. Therefore, the margin surface 5 is formed on the same circumferential surface around the rotation axis of the cutting tool 1, and all the margin surfaces 5 are formed at the same distance from the rotation axis of the cutting tool 1. For this reason, the margin surface 5 is not completely flat but slightly curved in the circumferential direction of the cutting tool 1. In the drawing, the margin surface 5 is shown flat.

  FIG. 4A is a schematic external view of the cutting edge portion 3 on a line parallel to the right twisted blade groove 7 and passing through the center of the margin surface 5, and FIG. 4B is a plan view thereof. is there. FIG. 5 is a developed schematic view of the cutting tool 1 (blade portion 1a). In FIG. 5, the left side in the drawing is the tip of the blade 1a of the cutting tool 1, and the right side is the shank 1b side. As described above, the margin surface 5 is formed on the upper surface of the cutting edge portion 3. The length L1 mm of a pair of parallel sides forming the margin surface 5 and the length L2 mm of other parallel sides (L2 ≧ L1) (see FIG. 4B) are parallel to the right twisted blade groove 7. When the number of rows of cutting edge portions 3 provided in the direction is n (see FIG. 5), it is desirable to satisfy the relationship of 2.5 / n ≦ L1 ≦ L2 ≦ 5 / n. Here, L1 and L2 may be the length of either the left helix blade 15 or the right helix blade 17. In the following description, L1 is a short side and L2 is a long side, but L1 = L2 is not excluded.

  When the short side length L1 of the margin surface 5 is smaller than 2.5 / n, the effect of forming the margin surface 5 is small. Further, when the long side length L2 of the margin surface 5 is larger than 5 / n, the contact area with the work material increases, so that the cutting resistance increases. For this reason, it is desirable that the side length Lmm of the margin surface 5 satisfies the above relationship.

  FIG. 6 is a cross-sectional view of the cutting edge portion 3. The cutting edge 3 is desirably provided with a surface coating 19. Here, the material of the cutting tool 1 is obtained by molding and sintering a mixed powder of WC powder and Co powder, and the surface coating 19 is a hard film such as diamond coat and DLC (Diamond Like Carbon). . The surface coating 19 can increase the surface hardness of the cutting tool 1.

  In the present invention, in order to form the margin surface 5, the cutting resistance against the work material is distributed in three directions (D, E, and F directions in the figure). That is, as compared with the conventional cutting tool 100, since the resistance applied to the cutting edge is multidirectional, vibration can be suppressed.

  Further, since the margin surface 5 is substantially flat, the surface coating 19 is easily attached to the top of the cutting edge portion 3, and the surface coating 19 is less likely to be peeled off as compared with the conventional cutting tool 100. Moreover, since the tip is not sharp, the strength of the top of the cutting edge 3 can be increased. Moreover, since it cuts with the margin surface 5, compared with the case where it processes with a sharp blade edge | tip, the surface roughness of a workpiece can be improved.

  Next, the cutting edge shape of the cutting tool was changed to cut the work material, and the cutting resistance at that time was investigated. As the cutting tool, a tool with 13 right-hand twist blades (number of right-hand twist blade grooves) and 15 left-hand twist blades (number of left twist blade grooves) was used.

Cutting conditions are: rotation speed: 10000 min ⁻¹ (cutting speed: Vc = 314 m / min), tool feed speed: Vf = 1000 mm / min, cutting amount in the tool axis direction × cutting amount in the tool radial direction: ap × ae = 10 × 10 mm Tool protrusion amount (overhang): OH = 45 mm. The cutting blade and air were blown. The work material was a CFRP material (dimensions 150 mm × 150 mm × 10 mm).

  A cutting tool having a blade diameter of 10 mm and a blade length of 30 mm was used. Moreover, the side length of the margin surface 5 was evaluated as 0 mm (no margin surface), 0.1 mm, 0.3 mm, and 0.5 mm, respectively. The margin surface is a rhombus, and the lengths of the four sides are almost the same. Trimming was performed on the work material with each cutting tool, and the cutting resistance at that time was investigated. The cutting resistance was investigated in three directions orthogonal to each other in the feed direction, the axial direction, and the radial direction of the tool.

  FIG. 7 is a diagram showing cutting resistance when the side length of the margin surface 5 is 0 mm (no margin surface), and FIG. 8 is a diagram showing cutting resistance when the side length of the margin surface 5 is 0.1 mm. 9 is a diagram showing a cutting resistance with a side length of the margin surface 5 of 0.3 mm, and FIG. 10 is a diagram showing a cutting resistance with a side length of the margin surface 5 of 0.5 mm. In each figure, the upper figure shows the cutting resistance (X direction) in the feed direction of the tool, the middle figure shows the cutting resistance in the radial direction (Y direction) of the tool, and the lower figure shows the cutting resistance in the axial direction (Z direction) of the tool. In each figure, the vertical axis represents cutting resistance (load) (N), and the horizontal axis represents time.

  As shown in FIG. 7, in the cutting tool that does not have the margin surface 5, the cutting resistance greatly fluctuates. For example, the cutting resistance in the X direction vibrates with a width of −800N to + 400N, the cutting resistance in the Y direction vibrates with a width of −500N to + 1000N, and the cutting resistance in the Z direction has a width of −400N to + 400N. Vibrated. Thus, a large vibration occurred in the tool. Moreover, when the surface roughness of the cut surface of the workpiece was measured, it was a large value of Ra = 11.15 μm. Moreover, since the variation of the cutting force was large, the maximum value of the cutting force was also increased.

  Further, as shown in FIG. 8, in the cutting tool having the margin surface 5 having a side length of 0.1 mm, the vibration of the cutting resistance in the tool radial direction was large as in FIG. For example, the cutting resistance in the X direction vibrates with a width of −1600N to + 1200N (average of about −300N), and the cutting resistance of the Y direction vibrates with a width of −400N to + 800N (average of about 400N). The cutting resistance vibrated with a width of −800 N to +800 N (average of about 0 N). In this example, the average value of the cutting resistance in each direction is smaller than the maximum value in the example of FIG. 7, but the vibration width is large. For example, as the cutting resistance in the feed direction (Y direction), a negative cutting resistance is generated. Further, when the surface roughness of the cut surface of the work piece was measured, Ra = 3.94 μm, which was improved compared to that without the margin surface, but achieved the target Ra = 3.2 μm. I couldn't. Thus, a sufficient effect could not be obtained when the side length of the margin surface 5 was 0.1 mm.

  On the other hand, as shown in FIG. 9, in the cutting tool having the side length of the margin surface 5 of 0.3 mm, the cutting resistance in all directions became almost constant. For example, the cutting resistance in the X direction was about −100 N, the cutting resistance in the Y direction was about +600 N, and the cutting resistance in the Z direction was almost zero. That is, the vibration is reduced. Moreover, the average value of the cutting force in each direction was also smaller than the maximum value in each direction in the example of FIG. In addition, the surface roughness of the cut surface of the work was measured, and Ra = 3.11 μm, and the target Ra = 3.2 μm was achieved. Since this cutting tool has n = 13 and L1 = L2 = 0.3 mm, 2.5 / n (≈0.19) ≦ L1 = L2 (= 0.3) ≦ 5 / n (≈0) .38) is satisfied.

  As shown in FIG. 10, in the cutting tool with the side length of the margin surface 5 being 0.5 mm, the cutting resistance in all directions was almost constant and the vibration was reduced. For example, the cutting resistance in the X direction was about −400 N, the cutting resistance in the Y direction was about +2400 N, and the cutting resistance in the Z direction was almost zero. However, the cutting resistance in the Y direction is larger than that of other cutting tools. For example, it is larger than the maximum value in the Y direction in FIG. This is because the contact area with the work material has increased because the margin surface 5 has become too large. In addition, the surface roughness of the cut surface of the workpiece was measured, and Ra = 5.38 μm, and the target Ra = 3.2 μm could not be achieved.

  Such a tendency was the same even when cutting tools having other numbers of blades were used. As described above, the cutting tool can form a surface satisfying the relationship of 2.5 / n ≦ L1 ≦ L2 ≦ 5 / n, thereby suppressing generation of vibration.

  As mentioned above, according to this Embodiment, the vibration at the time of cutting can be suppressed and cutting resistance can be made small by making the shape of a cutting blade part suitable. Further, by forming the surface, the strength of the blade edge can be increased and the surface coating can be made difficult to peel off.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

DESCRIPTION OF SYMBOLS 1 ......... Cutting tool 1a ......... Blade 1b ......... Shank 3 ......... Cutting edge 5 ......... Margin surface 7 ......... Right twist blade groove 9 ......... Left twist blade groove 11 ......... Left helix blade rake face 13 ......... Right helix edge rake face 15 ......... Left helix edge 17 ......... Right helix edge 19 ......... Surface coating 100 ......... Cutting tool 101a ......... Blade 101b ......... Shank 103 ......... Cut edge 107 ......... Right helix edge groove 109 ......... Left helix edge groove 111 ......... Rake face 113 ......... Cut edge 119 ......... Surface coating

Claims (4)

A cutting tool for trim processing,
The cutting tool comprises a blade portion and a shank,
The blade portion is provided with a right twist blade groove and a left twist blade groove with respective predetermined twist angles,
It consists of a plurality of cutting blade portions divided by the right twisting blade groove and the left twisting blade groove, the plurality of cutting blade portions are uniformly arranged on the blade portion,
The plurality of cutting edge portions have a substantially square frustum shape, and a substantially rectangular margin surface is formed at the top,
Each of the margin surfaces is formed on the same circumferential surface around the rotation axis of the cutting tool. The margin surface is a substantially parallelogram in plan view from the top side,
The length of one set of parallel sides of the margin surface is L1 mm, the length of the other set of parallel sides is L2 mm, and the number of rows of blades arranged in parallel to the right twisted blade groove is n. When
2.5 / n ≦ L1 ≦ L2 ≦ 5 / n
The cutting tool for trim processing according to claim 1, wherein:   The cutting tool for trim processing according to claim 1 or 2, wherein a surface coating is applied to an outer peripheral surface of the cutting tool. It is a manufacturing method of the cutting tool for trim processing according to claim 1,
A blade portion comprising a plurality of cutting edge portions divided by the blade groove, with a right-handed twisted groove and a left-handed twisted groove provided at a predetermined twist angle on the side surface of the base material with respect to the cylindrical base material. Form the
A trim characterized in that when forming the blade groove, a part of the cylindrical shape of the base material surface is left on the top so that the cutting edge portion has a substantially square frustum shape having a substantially square margin surface. A method of manufacturing a cutting tool for machining.

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