JP2001170810A - Twist drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drill improving supply of a lubricant and a coolant by mainly using air and gas as the drill for dry cutting and semi-dry cutting. SOLUTION: This twist drill constituted by applying a heat resistant film on it and with its base body constituted of high-speed steel, cemented carbide or TiCN group thermet is provided with coolant holes constituting characteristic features of opening the coolant holes at least on the chip discharge groove side of a third surface seen from a shaft end of the twist drill.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill having a coolant hole for cooling and / or lubrication in drilling a steel, a light alloy or the like.

[0002]

2. Description of the Related Art Conventionally, a cooling lubricant such as a water-soluble cutting oil for a drilling tool is supplied through at least one oil hole provided in a drill. This oil hole is opened outward through the outlet on the flank of the tip blade. The oil hole extends through the drill and through a supply port at the end of the drill shank, through a cooling lubricant or fluid suitable for cooling and / or lubrication generally during machining, such as liquids, gases, etc. A mixture is available. For example, when a water-soluble cutting oil is used, Japanese Patent Application Laid-Open No. H11-197
There is an example of opening to various parts such as 926. In recent years, dry machining without cutting oil has been applied in various fields, and drilling shapes and coatings suitable for dry machining have been proposed in drilling, but supply of coolant such as air and mist has been proposed. Is the same as when water-soluble cutting oil was used.

[0003]

As described above, the disadvantage of the conventional drill is that even in wet cutting using a water-soluble cutting oil, the cutting oil flowing out of the flank of the tip blade actually causes the tip to be involved in cutting. It is difficult to reach blades, chisel blades, and rake faces. In particular, the tip blade and the chisel blade generate high friction by performing cutting and deformation processing of chips, and thus generate high temperatures. There is no problem if the liquid is a liquid, but there is a limit to gas such as mist, cold air, and air in order to supply it sufficiently. In view of the above, the present invention is to propose a drill for dry cutting or semi-dry cutting, which mainly uses an air or gas system and in which the supply of a lubricant and a coolant is particularly improved.

[0004]

In order to solve the above-mentioned problems, the present invention provides a heat-resistant film coated with a high-speed steel substrate.
In a twist drill made of a cemented carbide or a TiCN-based cermet, a twist drill with a coolant hole characterized in that a coolant hole is opened at least on the chip discharge groove side of the third surface when viewed from the axial end of the twist drill. is there.

[0005]

According to the present invention, a coolant hole is provided at the end of the blade groove in order to cool and lubricate the next blade against the next blade without directly supplying the tip blade to be actually cut. Therefore, flank 3
By supplying coolant such as mist, cold air, etc. through the opening to the chip discharge groove side of the face, cooling the drill body, cooling and scattering chips, etc.,
Smooth chip discharge allows longer tool life. Furthermore, the amount of fluid required for cooling and / or lubrication is reduced.
The opening position is at least on the side of the chip discharge groove on the No. 3 surface in order to supply chips to the vicinity where chips are strongly compressed by abrasion. By setting this position, the coolant can be supplied particularly to the operation point where the load is large.

Furthermore, one or more openings may be provided in the blade groove. The groove or bottom of the groove is critical for the discharge of the chips, and the groove extending from the tip blade in the shank direction firstly removes the chips from the work material and turns them on the rake face, Next, it is deflected by the wall of the opposing blade groove, moves to the shank side along the twisted blade groove, and is discharged. At this time, if one or more openings are provided in the wall in the blade groove, the coolant is directly guided to the operation point as compared with the conventional arrangement in which the opening is arranged in the flank of the tip blade. Will be.

[0007] Furthermore, the opening may be provided on the rake face near the working area important for chip generation. The position on the rake face is an area adjacent to the tip blade. Depending on the intended use, the opening may be provided near the chisel blade, in particular on the rake face immediately adjacent to the chisel blade, or in an area relatively close to the corner. Hereinafter, the present invention will be specifically described based on examples.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an example of the present invention, a drill diameter of 8 mm made of ultra-fine-grain cemented carbide coated with TiAlN and molybdenum disulfide was used.
As shown in FIG. 1, a drill twist drill having a coolant hole opened on the chip discharge groove side of the third surface using
SCM440 (HB2) under the conditions of dry cutting using compressed air, cutting speed = 60 m / min, feed amount per rotation = 0.2 mm ⁻¹ , working depth = 24 mm, and compressed air.
50 to 300) were processed into 100 holes, and the state of the tip blade and the outer peripheral blade after the processing were observed.

[0009] For comparison, ten drills were also subjected to dry cutting in the same manner as in the conventional wet cutting, and the drill was provided near the leading edge of the flank, and the results are also shown in Table 1. .

[0010]

[Table 1] Note) ○: Drill without chipping and chipping at the tip blade and outer cutting edge ×: Drill with chipping and chipping at the tip blade and outer cutting edge

From Table 1, in particular, chipping and chipping of the outer peripheral edge clearly indicate whether or not chip discharge is performed smoothly. While chipping of the blade was observed at 1/10, in the conventional example, chipping of the tip blade and the outer peripheral blade occurred at 8/10.

Further, drilling was continued under the same cutting conditions. Maximum flank wear after machining 1000 holes VBmax
(Mm) is shown in Table 2. However, 1000
In the case where the life has been reached or the machine cannot be machined without drilling, it is indicated by the number of drilled holes.

[0013]

[Table 2]

From Table 2, it can be seen from the table that if the drilling is continued, the cutting edge is less likely to be chipped in the present invention, and the cutting edge can be cooled by the coolant. However, in the conventional example, the maximum wear on the flank due to chipping or chipping of the tip blade becomes large,
The life has expired because the 00 holes cannot be machined. In addition, entanglement of chips and the like increases, and it is necessary to continue drilling while removing entangled chips and the like.

[0015]

By applying the invention of the present application, by positioning the opening position of the coolant of the drill closer to the blade groove side, it is possible to discharge chips more smoothly and to achieve stable cutting performance. .

[Brief description of the drawings]

FIG. 1 shows a shaft end view of a drill according to an embodiment of the present invention.

FIG. 2 shows an end view of a conventional drill.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer edge 2 Tip blade 3 Chip discharge groove 4 Land part 5 3rd surface 6 Coolant hole O Shaft center

Claims (3)

[Claims] In a twist drill made of coated high-speed steel, cemented carbide or TiCN-based cermet, it is preferable that a coolant hole is opened at least on a chip discharge groove side of a No. 3 face when viewed from the axial end of the twist drill. Characteristic twist drill with coolant hole. 2. The twist drill with a coolant hole according to claim 1, wherein the twist drill has an opening in a chip discharge groove. 3. The twist drill with a coolant hole according to claim 1, wherein the twist drill has an opening on a rake face.