JP2016144865A - Processing method using drill and drill with coolant ejection hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve fine separation of chips by directly supplying a coolant to a part where a cutting blade comes into contact with a material to be cut and setting its supply pressure high to increase the cooling effect of the cutting blade.SOLUTION: A processing method using a drill having a coolant ejection hole 18 formed at the tip part of a main spindle 19 processes a material to be cut by supplying a coolant ejected from the ejection hole 18 to the contact part of the cutting blade 12 of the drill with the material to be cut. In this case, the coolant is ejected from the ejection hole 18 at the high pressure of 7 MPa or higher to 30 MPa or lower. Thus, a high cooling effect is achieved, and a service life can be extended by suppressing drill abrasion. A processing speed can be increased, and good efficient hole processing can be performed.SELECTED DRAWING: Figure 1

Description

  The present invention has a coolant injection hole on the tip end side of the drill, and by supplying coolant at a high pressure aiming at a contact portion between the cutting blade and the work material from the injection hole, The present invention relates to a drill with a coolant injection hole that cools, divides and discharges chips and, as a result, can increase the feed rate of the drill and enables efficient cutting.

  Conventionally, when drilling holes in light alloys such as aluminum and steel materials, drills are prevented from being damaged due to heat generated by rubbing between the cutting edge surface of the drill and the work material, and in order to extend the life of the drill. A coolant injection hole is provided on the tip side. The coolant supplied through the coolant supply passage penetrating through the main shaft of the drill is ejected from the ejection holes. In addition, drills for machine tools include a twist drill in which the coolant supply passage is twisted in the same manner as the main shaft, and a straight drill that is not twisted during manufacture.

  As shown in the drawing of Patent Document 1, a conventional general coolant injection hole is opened in the second flank. And the processing condition by this prior art is as showing in FIG. The coolant passes through the twisted coolant supply passage of the main shaft portion, and is ejected from an ejection hole opened in the second flank of the main shaft tip. Since this ejection is only ejected to the front side of the main shaft, it is ejected from the chip 2 of the work material 1 cut out by the cutting blade, and the cutting blade 3 is ejected from the work material 1. It is not supplied to the parts that come into direct contact. Therefore, there is a problem that the cutting blade 3 becomes high temperature due to friction with the work material 1, deformation / wearing occurs, and the life is shortened.

  The technique of Patent Document 1 has been developed to solve such problems. This patent document 1 discloses a case in which coolant injection holes (holes) are provided at three different locations depending on the purpose.

  As described in paragraph [0005] of Patent Document 1, the first installation location is the chip discharge groove side of the third flank face. It is described that the coolant is not supplied directly to the tip blade to be actually cut, but the next blade to be cooled is cooled and lubricated. Accordingly, it is described that the drill body is cooled with coolant, the chips are cooled and scattered, the chips can be discharged smoothly, and the tool life can be extended. However, these effects are only general effects of the coolant.

  Moreover, it is described that the opening position is set to the chip discharge groove side of at least the third surface because the chip is supplied to the vicinity where the chips are strongly compressed by rubbing. However, even if the opening position is at least on the side of the chip discharge groove on the third surface, coolant can be supplied aiming at a particularly heavy working point, but the coolant is directly applied to the part where the cutting blade and the work material come into contact. It could not be supplied and its effect was insufficient.

The second installation location of the coolant injection hole disclosed in Patent Document 1 is in the blade groove as described in paragraph “0006”. When one or more further openings are provided in the wall in the blade groove, the coolant is guided directly to the working location than in the conventional arrangement in which the opening is arranged on the flank face of the tip blade. Have been described.
However, the blade groove continues from the tip blade to the shank base end by twisting the curved groove inner surface, and even if a coolant injection hole is opened to the wall in the blade groove, contact between the cutting blade and the work material It is impossible to spray coolant directly onto the part. That is, when the coolant injection hole is opened in the blade groove, it is impossible to direct the coolant injection angle toward the contact portion between the cutting blade and the work material.

  As described in paragraph “0007”, the third installation location of the coolant injection hole disclosed in Patent Document 1 is near the working area important for chip generation on the rake face. Moreover, as the position on the rake face, there is a description that the opening of the ejection hole is provided near the chisel blade, particularly on the rake face directly adjacent to the chisel blade, or in an area relatively close to the corner. By the way, the rake face is a face extending from the cutting blade to the chip discharge groove, and usually forms a vertical wall surface.

  Even if an opening is provided in the rake face directly adjacent to the chisel blade in this way, the rake face itself is a vertical surface that continuously extends from the cutting blade to the chip discharge groove, so the opening is a certain distance from the position of the cutting blade. It can only be formed at a distance. Therefore, the coolant sprayed from the spray hole opened in the vertical surface comes into direct contact with the chips at a position separated by the distance. Therefore, the coolant cannot be directly supplied to the portion where the cutting blade and the work material are in contact with each other. Therefore, there has been a problem that the cooling effect of the cutting blade and the chisel blade is still insufficient.

  On the other hand, as the supply pressure of the coolant for this type of twist drill, the supply pressure is less than 7 MPa. The reasons for this are not understood, but there are no machine tool support, no holder tool, and no data of 7 MPa or more. As an exception, as shown in Patent Document 2, in the case of fine hole machining, in consideration of the large pressure loss, jetting is performed at a high pressure of about 10 MPa to 14 MPa.

JP 2001-170810 A JP 2004-042209 A

As described above, in the drill shown in Patent Document 1 or the like, a case is disclosed in which coolant injection holes are provided on the chip discharge groove surface of the third relief surface, on the chip discharge groove surface, and on the rake face. However, in any case, the coolant could not be directly ejected to a portion where the cutting blade and the work material contact each other.
Therefore, compared with the general technique of opening the coolant injection hole to the third flank, the position where the coolant is injected can be brought closer to the portion where the cutting blade and the work material contact, but the drill body and the workpiece The cooling and discharging effect of the cutting material was still insufficient.

Further, in the technique shown in Patent Document 2 and the like, the coolant supply pressure is set to about 10 MPa to about 14 MPa, but this is for narrow hole processing, and in general hole processing, the pressure is less than 7 MPa. It was. Therefore, the supply of coolant to the processing site is insufficient, and the cooling of the cutting blade and the discharge of chips are insufficient. Therefore, conventionally, after drilling a few millimeters, the drill is retracted once, the cutting blade is cooled and the chips are discharged, and then the drill is further advanced to perform cutting. It is generally inefficient to drill holes repeatedly.
In addition, when the supply pressure is less than 7 MPa, the chip breaking effect is lacking, so chips are continuously generated to a considerably long dimension, and the chips may not be discharged smoothly from the discharge groove of the drill. there were. In addition, long chips are bulky and difficult to be in an arbitrary storage form, which may be difficult to process.

  The present invention is an improvement and removal in view of the conventional problems described above, and the coolant is directly supplied to a portion where the cutting blade and the work material are in contact with each other, so that the cutting blade and the work material can be improved. Provide excellent cooling and synergistic effect of supplying coolant to the above part and increasing the supply pressure to achieve fine cutting of chips and facilitate chip discharge and subsequent processing. It is an object of the present invention to provide a machining method using a drill capable of performing a drill and a drill.

  The means of claim 1 adopted by the present invention in order to solve the above problem is a processing method using a drill in which a coolant injection hole is provided at a tip end portion of a main shaft, and the coolant injected from the injection hole is provided. A processing method using a drill, wherein the work material is processed while being supplied to a contact portion between the cutting blade of the drill and the work material.

The means according to claim 2 adopted by the present invention to solve the above-mentioned problems uses the drill according to claim 1, wherein the coolant is ejected from the ejection hole at a high pressure of 7 MPa or more and 30 MPa or less. It is a processing method.
The means of claim 3 adopted by the present invention to solve the above-mentioned problems is a drill with a coolant injection hole used in the machining method using the drill according to claim 1 or 2, wherein the drill has a main shaft. A drill with a coolant injection hole, characterized in that a coolant injection hole is provided at a tip portion, and coolant injected from the injection hole is injected toward a cutting blade.

According to the present invention, the coolant ejected from the ejection hole is supplied to a portion where the cutting blade and the work material are in direct contact with each other. Can be achieved. As a result, the processing speed can be increased, and excellent and efficient hole processing is possible.
Further, since the coolant is supplied to the portion where the cutting blade and the work material are in direct contact, there is an effect that the cut chips are easily divided into short dimensions.

  Further, the coolant is supplied to the contact portion between the cutting blade and the work material by ejecting the coolant at a high pressure of 7 MPa or more and 30 MPa or less, and the supply pressure is extremely high as described above. The chips scraped off from are immediately divided at an extremely short dimension, flow into the discharge groove together with the coolant, and are smoothly discharged out of the drill from the discharge groove. In this way, since the chips are divided into extremely short dimensions, it becomes easy to pass through the discharge grooves that are twisted around the main shaft. Moreover, after leaving | separating from a drill, it can accommodate in the container of arbitrary shapes, The process is also easy.

It is drawing which looked at the blade edge | tip of the drill with a coolant injection hole which concerns on 1st embodiment of this invention from the front. It is a side view which shows the main-axis front-end | tip part of the drill with a coolant injection hole which concerns on 1st embodiment of this invention. It is a side view which shows the main-axis front-end | tip part of the drill with a coolant injection hole which concerns on 2nd embodiment of this invention. It is sectional drawing which shows the relationship between the blade edge | tip of a drill with a coolant injection hole which concerns on embodiment of this invention, and a workpiece. It is sectional drawing which shows the relationship between the blade edge | tip of a conventional drill with a coolant injection hole, and a workpiece.

  The configuration of the present invention will be described below based on the first embodiment in the case of the twist drill shown in FIGS. 1 and 2. As shown in FIG. 1, the drill 11 of this embodiment is a twist drill formed of high-speed steel or cemented carbide, and two cutting blades 12 and 12 are provided at positions where they are symmetrical. It has a margin width M. A first flank 13 is formed after the cutting blade 12, and further leads to a second flank 14 and a third flank 15 and then to a chip discharge groove surface 16. Chisel blades 17 are formed between the cutting blades 12 arranged symmetrically. A triangular vertical surface 15 </ b> A is formed between the chisel blade 17 and the third flank 15.

Thus, in this embodiment, the coolant ejection hole 18 is formed across the third flank 15 and the chip discharge groove surface 16 connected to the third flank 15. The reason why the coolant injection hole 18 is provided at this position is to make the point where the coolant injected from the injection hole 18 reaches a portion where the cutting blade 12 and the work material come into contact.
A coolant supply passage 20 is formed in the main shaft 19 of the drill 11. The supply passage 20 is formed at the same time as the main shaft 19 is twisted by extrusion, and is formed with the same twist angle as the main shaft. Therefore, in order to determine that the coolant supplied through the coolant supply passage 20 is ejected from the ejection hole 18 toward the contact portion between the cutting blade 12 and the work material, the discharge is performed. It is important that the flank 15 facing the groove surface 16 is an inclined surface that is ground until the coolant ejected from the ejection hole 18 is ejected toward the cutting blade 12.

  This will be explained in more detail. In the case of the twist drill, the coolant supply passage 20 is also twisted to make the flank 15 the desired inclined surface, so that the opening of the ejection hole 18 is simply escaped. By only providing it on the surface 15, the coolant is only ejected toward the vicinity of the part where the cutting blade 12 and the work material come into contact with each other, and the cutting blade 12 directly supplies the work material to the work part. Because you can't. It is necessary to set the inclination angle of the flank 15 so that the tip of the coolant supply passage 20 extending in the twisting direction is the contact portion between the cutting blade 12 and the work material.

  In the present invention, by utilizing the fact that the coolant supply passage 20 of the main shaft portion is twisted, the coolant is cut by meshing the twist direction of the supply passage 20 with the inclination angle of the flank 15. The position directly supplied to the contact portion between the blade 12 and the work material is specified. The inventor has found that the position of the ejection hole 18 can only be a position straddling the chip discharge groove surface 16 and the flank 15 facing the discharge groove surface 16.

  Therefore, the coolant ejected from the ejection hole 18 according to the present invention is supplied to a portion where the cutting blade 12 and the work material are in direct contact with each other, which has an excellent cooling effect and wears the blade edge of the drill 11. It is possible to extend the life by suppressing it. As a result, the processing speed can be increased, and excellent and efficient processing is possible. It was possible to process at a speed of 7 times or more compared with the conventional processing method of repeating forward and backward.

Furthermore, in the present invention, the pressure of the coolant ejected from the ejection holes 18 and 21 is set to 7 MPa or more and 30 MPa or less by using a high pressure pump manufactured in-house. As a result, due to the synergistic effect that the coolant ejected from the ejection hole 18 is directly supplied to the contact portion between the cutting blade 12 and the work material, the chips scraped off from the work material are caused by the high-pressure coolant. It is immediately divided at an extremely short dimension and flows to the discharge groove 16 together with the coolant, and is smoothly discharged from the discharge groove 16 to the outside of the drill.
FIG. 3 is a drawing showing the relationship among the cutting blade 12, the work material 1, and the coolant supply state. As is clear from this figure, when the high-pressure coolant is supplied to the contact portion between the cutting blade 12 and the work material 1, the shaved chips are divided at an early stage and are transported to the discharge groove 16 by the coolant. It is discharged.

  Actually, the relationship between the coolant supply pressure and the chip size when the material of SCM415 (chrome molybdenum steel) is turned with a lathe is as follows. When the supply pressure of the coolant is 2 MPa, the length of the chip is 50 mm or more, about 30 mm when the pressure is 7 MPa, and about 15 mm when the pressure is 10 MPa, and about 7 mm when the pressure is 15 MPa. When the pressure was 20 MPa, the size was about 5 mm. When the pressure was 25 MPa, the size was about 3 mm. When the pressure was 30 MPa, the size was about 3 mm.

  In this way, since the chips are divided into extremely short dimensions, it becomes easy to pass through the discharge grooves 16 that are twisted around the main shaft. Moreover, after discharging | emitting from a drill, it can accommodate in the container of arbitrary shapes, The process is also easy.

FIG. 3 is a side view showing the tip end portion of the spindle of the drill according to the second embodiment of the present invention. In this drill, a coolant discharge groove 16 having a twisted main shaft portion is formed by machining from a round bar using a special machine tool, and a cutting blade 12, a first flank 13 and a second flank 14 are formed on the tip surface. The third flank 15 is formed, and a straight coolant supply passage 20A is formed on the central axis of the main shaft 19 by drilling. Then, a coolant ejection hole 18 is formed so as to straddle the third flank 15 and the chip discharge groove surface 16 connected thereto. The reason for providing the coolant injection hole 18 at this position is the same as in the case of the first embodiment, and the destination of the coolant injected from the injection hole 18 is the contact between the cutting blade 12 and the work material. This is to make it a part to perform.
Accordingly, also in this case, in order to determine the angle of ejection from the ejection hole 18 so as to be ejected toward the contact portion between the cutting blade 12 and the work material, the flank 15 facing the discharge groove surface 16 is formed. It is important that the inclined surface is ground until the coolant sprayed from the spray hole 18 is sprayed toward the cutting blade 12.

  Thereby, the coolant ejected from the ejection hole 18 is supplied to a portion where the cutting blade 12 and the work material are in direct contact with each other, and an effect substantially similar to that of the first embodiment can be obtained. it can. That is, the cooling effect of the cutting blade 12 and the work material by the coolant is excellent, and the wear of the cutting edge of the drill 11 can be suppressed to extend the life thereof. Furthermore, this makes it possible to increase the processing speed and to perform excellent and efficient processing.

Furthermore, in the case of this embodiment, by cutting the pressure of the coolant ejected from each ejection hole 18 and 21 to 7 MPa or more and 30 MPa or less, chips scraped from the work material can be extremely reduced. It can be cut at a short size and smooth discharge is possible.
Other configurations and operational effects are the same as those of the first embodiment.

  By the way, this invention is not limited to embodiment mentioned above, A suitable change is possible. For example, the number of cutting blades 12 and the inclination angle and twist angle of the third flank 15 can be appropriately changed. The cutting blade 12 may be a three-blade or more, and is not limited to two. In the twist drill, the number of coolant supply passages is also provided according to the number of these cutting blades.

DESCRIPTION OF SYMBOLS 11 Drill 12 Cutting blade 13 1st flank 14 2nd flank 15 3rd flank 16 Discharge groove 17 Chisel blade 18 Cutting hole coolant outlet 19 Main shaft 20 Coolant supply passage 20A Coolant supply passage

Claims (3)

A machining method using a drill having a coolant injection hole at the tip of the spindle,
A machining method using a drill, characterized in that the work material is machined while supplying the coolant ejected from the ejection hole to a contact portion between the cutting blade of the drill and the work material.   The processing method using a drill according to claim 1, wherein the coolant is ejected from the ejection hole at a high pressure of 7 MPa or more and 30 MPa or less. It is a drill with a coolant injection hole used for the processing method using the drill according to claim 1 or 2,
The drill is provided with a coolant injection hole, wherein a coolant injection hole is provided at a tip end portion of a main shaft, and coolant injected from the injection hole is injected toward a cutting blade. .

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