JP2005052940A - Drill with spiral hole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill with a spiral hole characterized by restraining cutting edge abrasion, by spreading fluid up to an outer peripheral part from a cutting edge central part, without increasing fluid supply pressure, by devising the spiral hole for supplying the fluid. <P>SOLUTION: This drill has the spiral hole for supplying the fluid such as cutting fluid or cutting mist or air toward the cutting edge vicinity on the tip side from the drill base end side. The drill with the spiral hole is characterized in that at least an opening part of the spiral hole is formed in a substantially triangular shape, and the ratio of the height/the bottom side of the substantially triangular shape is set to 0.4 to 0.6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a drill having a spiral hole inside a drill base.

  Since drilling is performed with a cutting edge at the tip, the external lubrication method makes it difficult for the lubrication to reach the cutting edge as the machining hole becomes deeper. The cutting edge temperature increased as the drilled hole became deeper, and the life was reached earlier due to the softening of the cutting edge. A drill with a spiral hole is used to improve these and to compensate for chip discharge. Even with a drill with a spiral hole, it is necessary to adjust the fluid supply pressure, etc., in order to allow the fluid to spread through the entire cutting edge. Patent Document 1 proposes a cutting tool with an oil hole in which the position of the opening on the flank on the drill tip side of the oil hole is defined by the cutting edge and the outer peripheral edge to improve the tool life.

JP 2002-52410 A

  The present invention is a drill with a spiral hole characterized by devising a spiral hole for supplying a fluid and suppressing the wear of the cutting edge by spreading the fluid from the center of the cutting edge to the outer periphery without increasing the fluid supply pressure. .

  The present invention relates to a drill having a spiral hole for supplying a fluid such as cutting fluid, cutting mist or air from the drill base end side to the vicinity of the cutting edge on the tip side, and at least the opening of the spiral hole is substantially triangular. A drill with a spiral hole, characterized in that the ratio of the height / bottom of the substantially triangular shape is 0.4 to 0.6.

  By applying the present invention, there is provided a spiral hole drill in which a supply fluid can be supplied in a fan shape over the entire cutting blade starting from the spiral hole, and the wear of the cutting edge is suppressed.

  FIG. 1 shows a drill with spiral holes in which openings of a pair of triangular spiral holes are provided in parallel with the cutting edge. The area of the supplied fluid decreases as it goes to both corners of the triangular base. By squeezing, the discharge speed is increased and diffused, so that the fluid spreads to the outer peripheral corner of the cutting edge where the cutting speed is high. The fluid is diffused along the cutting edge, and after the cutting edge is lubricated and cooled, it is used for chip discharge. Therefore, the effect of the fluid can be effectively used in a spiral hole with the same cross-sectional area. . The spiral hole has a triangular shape, has a cutting edge side as a bottom and a height toward the heel side, and the ratio of the height to the bottom is 0.4 or more and 0.6 or less. If it is 0.4 or less, the area of the spiral hole becomes small, insufficient supply of coolant occurs, and the supply fluid cannot be sufficiently diffused to the entire cutting blade. At 0.6 or more, the apex angle of the triangular spiral hole was about 80 °, and the diffusion angle was narrowed and supplied. The fluid cannot be spread over the entire cutting blade. When the opening position of the spiral hole in which the bottom side of the spiral hole is 45 ° or less rearward in the rotation direction from the cutting blade parallel is separated from the cutting blade, the supplied fluid is difficult to reach the cutting blade.

(Example 1)
Invention Example 1, the drill diameter = 8.0 mm made of cemented carbide, shown in FIG. 1, the opening shape of the spiral hole is triangular, Jikudan area of the spiral hole of about 1.0 mm ^2/1 well, spiral Cut the tip at a position where the ratio of the triangle height to the bottom of the hole is 0.5 (1.0 mm / 2.0 mm), the pitch of the spiral hole is 3.8 mm, and the bottom of the triangle of the spiral hole is 1.4 mm from the tip cutting edge. Almost parallel to the blade (phase angle from drill center = 0 °), twist angle 30 °, drill groove 100 mm, drill overall length 150 mm, drill core thickness 2.8 mm, thinning shape-X type, coated TiAlN. For comparison, as a conventional example 2, a spiral hole circle shown in FIG. 3, the spiral hole diameter = 1.13 mm, Jikudan area of the spiral hole is also prepared like about 1.0 mm ^2/1 well to.
The present invention example 1 and the conventional example 2 are each prepared in three, the cutting fluid is supplied from the base end with a pump of 1.5 Mpa and a flow rate of 30 l / min, and the SCM440 tempered material (HRC 28-30) is cut at a cutting speed of 100 m. / Min, feed 800 mm / min, machining depth = 40 mm, 1000 holes were machined, the edge of the blade and the wear width of the outer periphery of both flank surfaces were measured, and the average value of the three was taken as the measured value.
As a result, in Example 1 of the present invention, the average wear on the flank was 0.08 mm, and in the initial wear state, no chip welding was observed in the thinned portion, whereas in Conventional Example 2, the average wear width was 1. Wear progressed at 9 mm, and chip welding was also observed at the thinning portion.

(Example 2)
Drill opening triangular spiral hole of the present invention Example 1 and the specification about 1.0 mm ^2/1 hole spiral hole, Comparative Example 3, the ratio of height to base is 0.35 (0.85 mm /2.4 mm), Invention Example 4 is 0.4 (0.9 mm / 2.25 mm), Invention Example 5 is 0.60 (1.1 mm / 1.85 mm), and Comparative Example 6 is Three pieces each having the same 0.65 (1.15 mm / 1.75 mm) were prepared, and a drilling test was conducted in the same manner as in Example 1.
As a result, the flank average wear width of Comparative Example 3 = 1.75 mm, the flank average wear width of Invention Example 4 = 1.24 mm, the flank wear width of Invention Example 5 = 0.06 mm, and Comparative Example 6 The flank average wear width was 1.24 mm. In Comparative Example 6, the flank average wear width of one of the cutting edges was 0.06 mm, but slight chipping was observed on the outer peripheral portion of the other cutting edge. As a result, the ratio of the height and the bottom of the triangular spiral hole was set in the range of 0.4 to 0.6.

(Example 3)
A drill having the same specifications as in Example 1, and Example 7 of the present invention is a drill in which the shape of the opening of the spiral hole is a triangle, and the position of the base is parallel to the tip cutting edge (hereinafter, as shown in FIG. Phase angle θ from the center.) Phase angle θ = 0 °, Example 8 of the present invention is the phase angle θ = 15 °, Example 9 of the present invention is the phase angle θ = 30 °, Example 10 of the present invention is the phase angle θ = Three drills each having a phase angle of θ = 60 ° in Comparative Example 11 and a phase angle θ = 75 ° in Comparative Example 12 were prepared.
Using the above drill, ester-based oil was distributed in the form of mist from the compressor at a rate of 30 cc / hour at 0.5 Mpa and a flow rate of 1800 l / min into the air supplied to the spiral hole from the base end of the drill. Supplied, 1000 holes were machined with S50C (HV 160-180) at a cutting speed of 150 m / min, feed of 1500 mm / min, and machining depth of 40 mm, and the flank wear width at that time was measured with the left and right cutting blades and averaged The measured value was used.
As a result, the flank wear width of Invention Example 7 was 0.06 mm, Invention Example 8 was 0.09 mm, Invention Example 9 was 0.11 mm, Invention Example 10 was 0.16 mm, and Comparative Example 11 Was 0.26 mm and Comparative Example 12 was 0.39 mm, and Comparative Example 12 reached the wear limit of 0.4 mm. Thereby, if it is in the range of 45 ° from parallel to the cutting edge, the effect of suppressing the progress of wear is great. As a result, the position of the major axis of the spiral hole was changed from substantially parallel to 45 ° or less on the rear side from the cutting edge parallel.

FIG. 1 shows a front view of an example of the present invention. FIG. 2 shows the phase angle. FIG. 3 shows a front view of a comparative example.

Explanation of symbols

1: coolant hole opening 2: tip cutting edge θ: phase angle

Claims (3)

In a drill having a spiral hole for supplying a fluid such as cutting fluid, cutting mist or air from the base end side of the drill to the vicinity of the cutting edge on the front end side, at least the opening of the spiral hole is substantially triangular. A drill with a spiral hole, characterized in that the ratio of the height / bottom side is 0.4 to 0.6. 2. The drill with a spiral hole according to claim 1, wherein the bottom of the spiral hole is provided substantially parallel to the tip cutting edge or at a rear side of the tip cutting edge by 45 ° in the rotation direction. The drill with a spiral hole according to claim 1, wherein the drill is made of cemented carbide.

Images