JP2007075942A - Drilling tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce and prevent back burrs generated when a drilling tool passes through a workpiece in drilling and prevent burrless effect from decreasing even if wear develops due to continuous use. <P>SOLUTION: The drilling tool 1 machining a through-hole is intermitted in the axial direction from the vicinity of outer peripheral side end of tip end cutting blade 2 toward a leading edge. The tip end cutting blade 2 or the leading edge part is intermitted in a triangle shape, trapezoidal shape, or saw-tooth shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a burr-less drilling tool that does not reduce or generate burrs on the machining back surface by cutting burrs on the machining back surface that occur at the time of drilling in drilling with a drilling tool.

  When a through-hole is machined with a drilling tool, burrs (hereinafter referred to as back burrs) are generated on the outlet side. If the burrs are not removed, the assembled parts will not adhere to each other when assembled. It cannot be done or the dimensional accuracy cannot be maintained. As a method of reducing back burr at the time of drilling metal and non-ferrous metal or not causing the above-described assembly or the like to be hindered, Patent Document 1 discloses that an outer peripheral corner of a drilling tool is formed into an R shape or a tapered shape. Thus, the cutting edge angle of the cutting edge outer peripheral corner where the burr comes close is made closer to the drilling tool axial direction, the cutting thickness is reduced, and cutting is performed gradually to suppress the generation of burrs. Patent Document 2 discloses that, as a burr-less machining method, an ordinary drilling tool is used, and the outer peripheral corner portion of the drilling tool is 0.005 × drilling tool diameter or more 0.15 × drilling tool from the back of the workpiece. Drilling to a depth of less than the diameter, as secondary cutting, the feed of one rotation is drilling tool diameter × 0.2 times or more, drilling tool diameter × 1.4 times or less, the outer peripheral corner of the drilling tool Describes a machining method that completely penetrates the burr that was pushed out during the secondary cutting, by penetrating to a position that sufficiently exceeds the height of the burr, shearing while pulling up the burr at the outer periphery margin of the drilling tool Has been.

JP 2000-263306 A JP 2003-300108 A

  This invention made it the subject to reduce or not generate | occur | produce the back burr | flash which generate | occur | produces at the time of penetration in the hole processing with a drilling tool. Next, although the effect of burless drilling tools is excellent at the initial stage of use, the effect of burres decreases with wear, and the life of burrs is reduced due to the occurrence of burrs. It was also an issue to avoid it.

  The present invention is a drilling tool for machining a through hole, wherein the drilling tool is intermittent in the axial direction from the vicinity of the outer peripheral side end of the cutting edge to the leading edge. . By applying the present invention, the occurrence of back burrs that occur during penetration is reduced or eliminated, and deburring work after drilling becomes unnecessary.

  According to the present invention, a back burr generated at the time of penetration in drilling with a drilling tool can be reduced or eliminated, and a drilling tool free from burr can be provided without being constrained by the state of the processed back surface. Furthermore, in the case of intermittent burr in combination with the taper, burr can be removed and the burr at the time of penetration can be cut with less wear at the next cutting edge of the intermittent point, so the effect of burr-less Was obtained for a long time.

  When a through-hole is machined with a general drilling tool, the drilling tool presses the workpiece with a cutting feed and cuts, so the burr at the time of penetration is generated by being pushed out by the cutting edge of the tip. Although it tries to shrink inward by force, the outer diameter part of the drilling tool is a continuous cylindrical shape, so the elastic restoring force of the burr gradually disappears, and the burr part sticks by stopping trying to shrink inside, It protrudes to the exit side. In the drilling tool of the present invention, the outer diameter portion of the drilling tool is formed in the burr portion generated by being pushed out by the tip cutting edge when penetrating, by being interrupted from the vicinity of the outer peripheral end of the tip cutting edge to the leading edge. Since the contact area and time are small, the burr does not lose its elastic restoring force, and the burr is bitten and removed by contracting toward the interrupted cutting edge or the valley of the edge. The In addition, the outer peripheral side edge vicinity of the front-end | tip cutting edge points out the cutting edge concerning the connection part of a front-end | tip cutting edge and a leading edge.

The cutting edge or edge interrupted in the axial direction bites and removes burrs at the troughs by interrupting the cutting edge or edge. It is necessary to make it small, and it is preferable that the shape be provided in the shape of a triangle, trapezoid, or saw blade.
Next, the reason why the depth of the valley is 0.03 or more and 0.2 or less of the diameter of the drilling tool is that if the diameter is 0.03 or less, the shrinking burr cannot be sufficiently caught on the valley, The action of pulling up the burrs in the direction of the hole entrance becomes insufficient, and the generation of burrs cannot be completely prevented. If it is 0.2 or more, the strength of the drilling tool blade tip is lowered and the risk of causing chipping increases.
The reason why the number of locations interrupted in the axial direction is 2 to 20 is that the length of the cutting edge or leading edge interrupted in the axial direction becomes too long when the number of locations exceeds 20 is set to 2 to 20 locations. More preferably, it is 2-10 places.

Even if the cutting edge or edge interrupted in the axial direction is parallel from the outer diameter part of the drilling tool adjacent to the tip cutting edge toward the rear end side in the axial direction, burr can be prevented. When drilling, the drilling tool is likely to sway and the hole expands.Therefore, when the hole expands, if the cutting blades or edges interrupted in the axial direction are parallel, the burr should be sufficiently axial. Since it can not be caught in the valley of the interrupted cutting edge, the action of pulling up the burr in the direction of the hole entrance becomes insufficient, and it may not be possible to completely prevent the occurrence of burr, so toward the rear end side in the axial direction The adverse effect of parallelism can be eliminated by using a tapered shape with a large diameter. By providing the taper, the effect of burres is further maintained even by wear during initial use and continuous use.
When the taper is 1/5 or more, the angle of the taper becomes strong, the cutting resistance increases, and the risk of chipping of the cutting edge or edge interrupted in the axial direction increases. If the cutting edge that is interrupted in the axial direction is configured with a combination parallel to the taper toward the rear end side in the axial direction, the diameter of the machined hole is constant because the diameter of the cutting edge that is interrupted in the axial direction is constant in the parallel part. Is more stable. The taper length is set to 5 times or less the diameter of the drilling tool. Even if the taper length is 5 times or more, the effect is sufficiently maintained, but the hole depth to be processed becomes a deep hole, which is a wasteful process when manufacturing the drilling tool. Is to avoid. More preferably, it is 0.5 to 2.0 times.

  An axially interrupted cutting edge or trough of the edge is provided in the circumferential direction of the tool by 1/4 to 4/4 of the land width, and the crest is axially oriented at an angle of 1 to 5 degrees in the circumferential direction of the tool. The reason for inclining to the rear end side is that the burr generated by being pushed out by the cutting edge at the time of penetration contracts toward the interrupted cutting edge or the valley of the edge, and the burr is interrupted. The trough is inserted into the trough, passes through the groove from the trough, and is discharged to the outside of the tool. Therefore, the trough may be provided for the land width in the circumferential direction of the tool. The generated burr can be bitten and discharged. At that time, if the crest is inclined to the axial rear end side in the tool circumferential direction, the cut burr can be lifted up to the axial rear end side, so that the angle is 1 to 5 degrees toward the axial rear end side. It may be inclined. Hereinafter, the present invention will be described based on examples.

Example 1
As Example 1 of the present invention, using a high-speed drill with a drill diameter of 8.0 mm and a groove length of 24 mm as shown in FIG. 7 edges in the shape, 12mm in the axial direction, each edge is manufactured with a mountain angle of 60 °, a valley depth of 0.64mm, and a trapezoid top side length of 0.12mm, as shown in Fig. 2 did. A margin 9 is provided on the rear end side in the axial direction. As Example 2 of the present invention, the same specification as Example 1 of the present invention, as shown in FIG. 3, a normal leading edge 3 is provided from the end of the tip cutting edge 2, and thereafter is interrupted in the axial direction with a 1/10 taper. I made a drill. The coating was coated with TiAlN. For comparison, a JIS standard drill was also tested as Conventional Example 3.
Hole machining uses a vertical machining center, SS400 steel plate with a thickness of 10 mm is used as a processing material, cutting conditions are V = 10 m / min, oil-based cutting oil is used, feed through holes per rotation, Changed to 0.10mm / rev, 0.30mm / rev, 0.50mm / rev and machined 5 holes at each feed rate, measured the back burr height value (mm) at this time, measured value It was. The state of occurrence of burrs and the state of cutting are indicated by ◯, Δ, × and are shown in Table 1.
In Table 1, the symbols used for the state of occurrence of burrs are as follows: ○: Finished with 5 holes and no burrs; △: Finished with 5 holes and generated burrs on part of the holes. Indicates that the hole has been drilled and the occurrence of burrs has adhered to the entire periphery of the hole. The symbol used for the cutting state indicates that the hole has been drilled and has been used continuously. In a possible state, Δ mark: indicates that abnormal cutting noise was generated by vibration during the 5-hole machining.

From Table 1, Examples 1 and 2 of the present invention show that burring is less than 0.12 mm at a feed amount of 0.10 to 0.50 mm / rev per rotation, and no deburring work is required. Although the state was also good, in the case of Conventional Example 3, burrs were generated in all five, and the burr height in a state of protruding to the outlet side was confirmed to be about 1 to 2 mm.
Next, when the test of Invention Example 1 was continued and the state of 201 to 205 holes was confirmed, the deburring work was at an unnecessary level although it was slightly worse than the initial 5 holes.

(Example 2)
As Invention Examples 4-6, the depth of the valley of the edge intermittent in the axial direction is 0.03 times the drill diameter (0.24 mm) and 0.12 of the drill diameter with the same specifications as in Invention Example 1. Double (0.96 mm), 0.20 times (1.60 mm) the drill diameter. Cutting specifications and the like were the same as in Example 1.

  From Table 2, Invention Examples 4 to 6 were able to reliably remove burrs by deepening the valleys, and the burrs were interrupted by contracting toward the valleys of the interrupted edges. Since it is bitten by the valley of the edge, the height of the back burr can be further reduced.

(Example 3)
As Invention Examples 7 to 11, the same specification as that of Invention Example 1 and as an edge interrupted in the axial direction, trapezoidal cutting edges are provided in two places in Invention Example 7 and five places in Invention Example 8 Invention Example 9 was provided at 10 locations. Invention Example 10 was provided at 15 locations, and Invention Example 11 was provided at 20 locations. Cutting specifications and the like were the same as in Example 1.

  From Table 3, Invention Examples 7 to 11 were able to remove the back burr more reliably by increasing the number of interrupted edges, and the burr height was slightly higher at two locations. The burr was sufficiently removed at 5 or more locations.

Example 4
As Invention Examples 12 to 14, the same specifications as in Invention Example 1, and as a cutting edge or edge interrupted in the axial direction, taper from the vicinity of the drill outer diameter portion including the tip cutting edge toward the axial rear end side. 12 mm, and as Example 12 of the present invention, taper 1/10, Example 13 of the present invention, taper 1/5, Example 14 of the present invention, taper 1/10 of 8 mm, followed by 4 mm of parallel part Produced. For comparison, a comparative example 15 having a taper 1/4 was also manufactured. Cutting specifications and the like were the same as in Example 1.

  According to Table 4, Invention Examples 12 to 14 can more reliably remove burrs by combining the taper and the parallel part, and in particular, the taper part and the parallel part of Example 14 of the invention are combined. In the combined example, the accuracy of the hole was good and deburring was unnecessary.

FIG. 1 shows a perspective view of a drilling tool of Example 1 of the present invention. FIG. 2 shows an enlarged view of the main part of FIG. FIG. 3 shows a perspective view of the drilling tool of Example 2 of the present invention.

Explanation of symbols

1: Drilling tool 2: Cutting edge at leading edge 3: Leading edge 4: Cutting edge or edge portion interrupted in axial direction 5: Length of interrupted portion 6: Angle of trapezoidal peak 7: Trapezoidal valley Depth 8: Trapezoid top side length 9: Margin

Claims (7)

A drilling tool for machining a through hole, wherein the drilling tool is intermittent in the axial direction from the vicinity of the outer peripheral side end of the tip cutting edge to the leading edge. 2. The drilling tool according to claim 1, wherein the tip cutting edge or the leading edge is intermittently formed in a triangular shape, a trapezoidal shape, or a saw blade shape. 3. The drilling tool according to claim 1, wherein the depth of the valley of the cutting edge or the edge portion interrupted in the axial direction is 0.03 or more and 0.2 or less of the drilling tool diameter. A featured drilling tool. The drilling tool according to any one of claims 1 to 3, wherein 2 to 20 cutting edges or edge portions intermittent in the axial direction are provided. 5. The drilling tool according to claim 1, wherein the cutting edge or edge intermittently provided in the axial direction has a taper of 1/5 or less and a taper length of 5 times or less of a drilling tool diameter. Drilling tool characterized by. The drilling tool according to any one of claims 1 to 5, wherein the cutting edge or the valley portion of the edge portion interrupted in the axial direction has a length of 1/4 to 4/4 of the land width in the tool circumferential direction. A drilling tool characterized by being provided. The drilling tool according to claim 6, wherein the axially interrupted cutting edge or the peak portion of the edge portion is inclined toward the rear end side in the axial direction at an angle of 1 degree to 5 degrees in the tool circumferential direction. Drilling tool characterized by.

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