JPS6389210A - Drill - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a burr and a fracture on a workpiece by removing the burr generated on a drill through grinding and applying surface roughness of 3mumRz or less to the chip discharge direction of a drill groove and about 0.01mm radius to the external end of a cutting edge. CONSTITUTION:A drill 8 is processed in such a way that a burr generated thereon is removed by grinding, the surface roughness thereof is 3mumRz or less at a groove 9 in a chip discharge direction and an edge 11a of about 0.01mm radius is formed on the external end 11 of a cutting edge part 10. And the cutter part of the drill 8 is immersed, for example, in an ionizing solution and a negative electrode is provided in the solution, thereby applying electrolytic polishing to the drill 8 under an electric charge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to the structure of a small diameter drill used, for example, in precision machining, and particularly relates to improving the shape and roughness of the cutting edge and groove.

(Prior Art) Hereinafter, the structure of a conventional small-diameter drill will be described with reference to FIGS. 4 and 5.

FIG. 4 is a side view of a conventional drill 1 having a diameter of 2a* or less. This drill 1 is integrally provided with a shank 2 which is a part that is fixed to a machine tool such as a drilling machine. A blade portion 3 is provided at one end of the shank 2.

Further, the blade portion 3 has a cutting edge portion 4, a groove portion 5, and the like. The cutting edge portion 4 and the groove portion 5 are finally finished by being ground by a grinding machine during manufacturing.

The drill 1 finished as described above has a grinding paris 6 in the groove portion 5 and the cutting edge portion 4, as shown in FIG.

This grinding burr 6 is about 0.01 #lIm.

When a workpiece (not shown) is machined using the drill 1 with this grinding burr 6, the inside of the hole is scratched at the initial stage of drilling, which may reduce the accuracy of the drilled hole, or the workpiece may be damaged on the penetrating side of the drill 1. Occasionally, problems such as pari or missing may occur. Here, the workpiece is a raw ceramic material, a printed circuit board, a plastic, or the like. Further, since the groove 5, which is formed as a discharge groove for chips (not shown) cut out by the drill 1, has a rough finish, the chips cannot move smoothly on the surface of the groove 5, which prevents the chips from clogging. It was the cause.

The cutting edge portion 4 of the conventional drill 1 is as follows.

As mentioned above, it is only finished by grinding,
The outer circumferential end 7 is formed into a sharp edge as shown in FIG. 5, but even if a drill 1 with such a shape is used, it may cause cracks or chips in the workpiece as described above. It had become. Therefore.

Conventionally, the above-mentioned grinding chips have been removed by hand honing using a honing stone, but there have been problems such as damage in drills with a diameter of 1 m or less, and inability to uniformly hone even in drills with a diameter of 2 m or more.

(Disadvantages to be Solved by the Invention) As described above, conventional drills undergo grinding for the final finish, resulting in grinding chips at the cutting edge and groove. For this reason, cracks or chips may occur in workpieces machined using this drill. Also,
Due to the high roughness of the groove, the chips could not be discharged smoothly, leading to clogging of the chips. moreover,
Since the edge of the outer peripheral edge of the cutting edge is sharp, there is a drawback that when the blade penetrates the workpiece, it is likely to cause burrs or chips on the penetrating side.

This invention was made in view of the above circumstances.

To provide a drill that does not cause cracks or chips on a workpiece by polishing the blade part after grinding.

[Structure of the invention]

(Means and effects for solving the problem) This invention has the following features:
In a drill in which the groove and cutting edge of the blade are ground, the grinding burrs generated by the above grinding process are removed by polishing, and the roughness of the groove in the chip flow direction is set to 3 IRRZ or less, and the cutting edge is polished. It is an object of the present invention to provide a drill capable of drilling a hole in a workpiece without causing cracks or chips by providing an edge having a radius of about 0.01 s at the outer peripheral end.

(Example) The following is an example of the present invention in Figures 1 to 3.
This will be explained with reference to the drawings, but since its basic structure is the same as the conventional example shown in FIGS. 4 and 5, the same parts are given the same reference numerals and the explanation will be omitted.

The vicinity of the cutting edge of the drill shown in FIG. 1 is that of the polished drill 8 according to the present invention. This drill 8 is a small diameter drill with a diameter of 2 m or less.

Such a structure of the drill 8 is such that the grinding pad 6 formed by the conventional final finishing process is removed by a polishing method described later, and this polishing method improves the surface roughness of the groove 9 in the chip flow direction. 3pltR2 or less, that is, smoother, and 0.0 on the outer peripheral edge 11 of the cutting edge portion 10
An edge 11a having a radius of about 1 s is provided.

The above polishing method will be explained below with reference to FIGS. 2 and 3.

First, chemical polishing, which is the first polishing method, will be explained. This is a method in which the drill 8 is immersed in an etching solution (not shown). As this etching solution, for example, a 2% solution of HNO3 or a 50% solution of birophosphoric acid is used.

Further, the second polishing method is based on electrolytic polishing. As shown in FIG. 2, the container 12 is filled with an ionized liquid 12a, the blade part 13 of the drill 8 is immersed in the ionized liquid 12a, and a positive electrode is connected to the drill 8. Further, a negative electrode is provided in the electrode 11112a to form two circuits, and electrolytic polishing is performed by applying charges to these circuits.

The third polishing method is a method using abrasive grains 14 shown in FIG.

In this polishing method, a drill 8 identified by a fixing member 16 is set up in a container 15 filled with abrasive grains 14.

Next, the container 15 is placed on the vibrating section of the ultrasonic vibrator 17, and the ultrasonic vibrator 17 is driven to perform polishing. Here, the abrasive grains 14 used have an abrasive particle size in the range of 320 to 4000.

By polishing using any of the polishing methods described above, the drill 8 shown in FIG. 1 can be obtained.

By obtaining the drill 8 with the above-described structure, it is possible to prevent damage such as cracks and chips in the workpiece, and even when the drill 8 with a diameter of 1jI11 or less is polished and finished. It is possible to polish the drill 8 without damaging it. Here, the above-mentioned workpieces include raw ceramic materials, printed circuit boards, plastics, and the like.

Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the drill 8 is a small diameter drill, but the present invention can be practiced regardless of the diameter of the drill. Further, the polishing method of the present invention is not limited to the first to third polishing methods described above, and any method in which the final finish of the blade of the drill is performed by polishing and the drill is polished into a shape that meets the gist of the present invention. Bye.

〔Effect of the invention〕

As explained above, according to the present invention, grinding burrs on the cutting edge and groove are removed, and an edge with a radius of about 0.01 mm is provided on the outer circumferential edge of the cutting edge, thereby preventing burrs and chips on the workpiece. Furthermore, it is possible to perform hole drilling without causing damage.

Since the roughness of the groove in the chip outflow direction is finished with high precision such that it is 3 RZ or less, it is possible to provide a drill that smoothly discharges chips from the workpiece and prevents clogging of chips.

[Brief explanation of the drawing]

FIGS. 1 to 3 show one embodiment of the present invention, and FIG. 1 is a side view showing the tip of the drill blade. 2 and 3 are schematic front views of each device for polishing a drill, FIGS. 4 and 5 show a conventional example, FIG. 4 is a side view of the drill, and FIG. 5 is a schematic front view of each device for polishing a drill. FIG. 3 is a side view showing the vicinity of the cutting edge of the drill. 6,...Grinding Paris, 8...Drill, 9...Groove,
10...Blade tip portion, 11...Outer peripheral end, 11a...Edge.

Claims (1)

[Claims] In a drill whose groove and cutting edge are formed by grinding, grinding burrs generated in the groove and cutting edge during the grinding process are removed by polishing, and the roughness of the groove in the chip flow direction is set to 3 μmRz or less. A drill characterized in that an edge having a radius of about 0.01 mm is provided at the outer peripheral end of the cutting edge.