JPS63306812A - Drill for boring complex material - Google Patents

Abstract

PURPOSE:To bore a combined material of complex material and metal with high accuracy by constructing the tip portion of drill with a primary cutter having tip shape of metal drill and a flat secondary cutter continuous to the primary cutter and having smaller tip angle than that of the primary cutter. CONSTITUTION:Tip portion 11 of drill 10 is constructed with a primary cutter 11A and a secondary cutter 11B formed continuously thereto. The primary cutter 11A has same tip shape as that of metal drill, while the secondary cutter 11B has flat shape known as dagger drill. When complex material and metal are bored under overlapped condition, metal is bored first by the primary cutter 11A followed by boring of complex material, and delamination at the outer circumference of hole is removed precisely through subsequent boring with the secondary cutter 11B around the primary hole. When cutting quantity of secondary cutter 11B is set considerably lower than that of the primary cutter 11A, abrasion of metal due to the secondary cutter 11B can be suppressed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drill for drilling composite materials, and in particular, a drill for drilling composite materials that is suitable for drilling into composite materials of superimposed fiber resin hardened materials and metal materials. Regarding drills for drilling materials.

[Prior Art] Fiber-resin cured composites, which are made by laminating fibers and impregnating them with resin and curing them, are widely used as industrial materials, especially as materials for aircraft. In the assembly process of aircraft production, in order to combine composite parts and metal parts such as aluminum, holes of the same diameter are often drilled through the parts and riveted together.

However, as shown in Fig. 11, when a metal drill 3 is used to drill a hole from the side of the composite material 1 with the composite material part 1 and the aluminum part 2 stacked one on top of the other, the composite material has weak adhesion between the layers. On the entrance side (drilling start side), the fibers of the composite material are lifted by the helix angle α and rake angle of the drill,
Particles, cracks, and delamination, that is, delamination, occur.

On the other hand, when drilling is performed from the aluminum part 2 side as shown in FIG. 12, the drill thrust force causes the fibers to separate at the drill exit side, causing delamination and the like. Such delamination etc. significantly shortens the life of the composite material. To prevent this, conventional practice has been to tighten the back-up material onto the exposed surface of the composite material and then drill the holes. However, this work of tightening the backup material is time-consuming and, if the workpiece is box-shaped, it may be impossible to mount the backup member inside.

Various drills for composite materials that prevent delamination and the like have been developed. For example, Jitko Sho 59-33546
No. 58-149114 discloses a composite material drill particularly suitable for aramid fiber-based composite materials.

However, these cannot be used for carbon-based composite materials or metals because of excessive wear and damage on the cutting edge.

Therefore, a dagger drill disclosed in US Pat. No. 4,093,395 was developed as a drill that exhibits excellent performance even with carbon-based composite materials. As shown in FIGS. 13 to 15, this dagger drill has rake planes 5 formed on both sides of the drill body 4. The pair of rake flat surfaces 5 are tapered to converge toward the tip 6, and the tip is ground to form a front flank surface 5A, thereby forming a cutting edge 7 with a tip angle A of approximately 35''. has been done.

The cutting edge 7 has a negative rake angle B of about 5'' and a clearance angle C of about 55''. In this manner, the tip cutting edge 7 has a negative rake angle B and a large clearance angle C, so that delamination and the like can be prevented from occurring and the life of the cutting edge can be extended. Furthermore, the pair of tapered flat surfaces 5 facilitate the removal of chips.

[Problems to be solved by the invention] However, when this dagger drill is used for metal, it suffers from significant wear and tear, and cannot be used to drill holes in composite parts and metal parts that are stacked one on top of the other. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a drill for drilling composite materials with excellent durability, which can drill holes in composite materials and metal in a stacked state without using a back-up material and without occurrence of delamination or the like. It is in.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a drill tip that is formed continuously with a primary cutting edge having the tip shape of a metal drill, and a primary cutting edge that has the tip shape of a metal drill. , and a flat secondary cutting edge having a tip angle smaller than the tip angle described above.

[Function] When a drill with such a configuration is used to drill a hole in a composite material and a metal layered together, the primary cutting edge of the drill tip first drills a relatively small-diameter primary hole, then the secondary cutting edge. The blade pierces the outer periphery of the primary hole drilled by the cutting edge to form a secondary hole.

Since the primary cutting edge at the tip of this drill has the shape of the tip of a metal drill, there is no problem of wear or damage, but delamination occurs around the primary hole in the composite material. However, this delamination around the primary hole is removed when the outer periphery of the primary hole is bored by the secondary cutting blade. Also,
Since the secondary cutting edge mentioned above is a flat cutting edge, it is easily subject to wear and damage due to metal drilling, but the cutting amount of the secondary cutting edge should be made sufficiently smaller than that of the primary cutting edge. [Embodiment] An embodiment of the drill for drilling composite materials according to the present invention will be described below as a first embodiment of the drill for drilling composite materials according to the present invention.
This will be explained with reference to FIGS. 10 to 10.

In FIG. 1, a drill for drilling a composite material 10 has a tip portion 1.
A helical groove 13 for discharging chips is carved on the outer peripheral surface from 1 to the vicinity of the shank portion 12, and this tip 11 has a primary cutting edge 11A and a secondary cutting edge 11 formed continuously thereto.
It is composed of B. This primary cutting edge 11A has the same or almost the same shape as the tip of a metal drill, and the secondary cutting edge 11B has the same or almost the same shape as a flat cutting edge known as a dagger drill. Almost identical.

When drilling a composite material and a metal in an overlapping state with a drill having such a configuration, the primary cutting edge 11A of the drill tip 11 first drills a relatively small-diameter primary hole, and then the secondary cutting edge lIB A secondary hole is formed by drilling the outer periphery of the primary hole drilled by the cutting blade 11A. This primary cutting edge 1
1A has the shape of the tip of a metal drill, so there is no problem of wear or damage, but delamination occurs at the outer periphery of the primary hole in the composite material. However, this delamination on the outer periphery of the secondary hole is removed when the secondary cutting edge 11B drills the periphery of the primary hole, and this secondary cutting edge 11B is a flat cutting edge that prevents delamination. Therefore, delamination does not occur in the second hole after all.

Although the secondary cutting edge 11B is easily subject to wear and damage when drilling metal, the cutting amount of the secondary cutting edge 11B can be reduced to that of the primary cutting edge 11B.
By setting the amount of cutting to be sufficiently smaller than the amount of cutting A, the wear and damage can be made sufficiently small to the extent that there is virtually no interruption.

The helix angle α of the helix groove 13 is approximately 20° to 30″.
is preferable, the tip angle β of the primary cutting edge 11A is determined depending on the type of metal to be drilled, and is generally preferably about 90″, and the tip angle γ of the secondary cutting edge 11B is about 20° to 30°.
In addition, as shown in FIGS. 2(a) and (b), the ratio d/D of the maximum diameter d of the primary cutting edge 11A to the maximum diameter of the secondary cutting edge 11B (this ratio is (referred to as angle position ratio) is preferably about 1/2 to 2/3.

Also, as shown in Figures 3 and 4, the relief angle δ is approximately 2.
0° to 25° is preferred. Specific examples of these values are shown below. α-20″, β-90@, γ-30″, δ
-2011.

FIG. 5 shows the helix angle α and tip angle β of the drill on the horizontal axis, and the delamination transport factor expressed as delamination width/hole diameter on the vertical axis.

As is clear from this graph, the torsion angle α−20”~
30'' and the tip angle β-906, the probability of delamination occurring is lowest.

Figure 6 shows the relationship between the angle angle γ of the secondary cutting edge 11B and the delamination incidence rate, and shows that
It shows that the range of 0@ is suitable. Also, the seventh
The figure shows the relationship between the angle position ratio d/D and the delamination occurrence rate, which is preferably in the range of about 1/2 to 2/3.

Further, FIG. 8 shows the relationship between the clearance angle δ and the delamination incidence rate, and a range of 20° to 25° is preferable.

FIG. 9 shows a second embodiment of the present invention, which is suitable for drills with a larger diameter than that in FIG. 1 (approximately 10 to 20+n). (Similarly, it is composed of a primary cutting edge 11A shaped like the tip of a metal drill and a secondary cutting edge 11B shaped like the tip of a dagger drill.

Behind this secondary cutting edge 11B, a tertiary cutting edge 15 having the same shape as the secondary cutting edge 11B is formed in a stepped shape through a cutting edge portion 14 that is substantially parallel to the axis of the blade. This tertiary cutting edge 15 is
As shown in FIGS. 10(a) and 10(b), it is preferable that the angles γ and δ are 20° to 30″ and approximately 20° to 25″, respectively. With such a configuration, the primary cutting edge 11A and the secondary cutting edge 11B of the tip portion 11 first drill a pilot hole, and the tertiary cutting edge 15 drills the outer periphery of this pilot hole.

In this way, since the tertiary cutting edge 15 only drills the outer periphery of the pilot hole, the drilling load is small and wear and damage are extremely small even when cutting metal. Further, since the tertiary cutting edge 15 is guided by the engagement between the tip portion 11 and the pilot hole, vibrations are suppressed and highly accurate drilling can be performed.

[Effects of the Invention] As is clear from the above description, according to the present invention, the drill tip has a primary cutting edge having the tip shape of a metal drill and a flat secondary cutting edge continuous to the leading edge. Because it is composed of a blade, it is possible to drill holes with high precision in composite materials and metals that are stacked together without the need for back-up materials (without denominations, etc.), and furthermore, it is possible to improve durability. .

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a drill for drilling different materials according to the present invention, FIGS. 2(a) and (b) are side and front views showing an enlarged tip of the drill, and FIG. The figure is an enlarged front view of the tip of the drill, and Figure 4 is I of Figure 2(b).
5 is a diagram showing the relationship between the helix angle and tip angle of the drill and the delamination factor, and FIG. 6 is a diagram showing the relationship between the angle angle γ and the delamination incidence rate. The diagram shown in Figure 7 shows the angle position ratio d/
A diagram showing the relationship between D and the delamination occurrence rate, FIG. 8 is a diagram showing the relationship between the relief angle δ of the cutting edge and the delamination occurrence rate, and FIG. 9 is another example of the present invention. 10(a) is a front view showing an enlarged view of the second cutting edge, and FIG. 10(b) is a front view showing a drilling drill shown in FIG. 10(a). 11 and 12 are explanatory diagrams showing the state when drilling a composite material with a metal drill, respectively. FIG. 13 is a perspective view showing a conventional dagger drill, and FIGS. FIG. 15 is a side view and a plan view, respectively, taken along the lines EE and FF in FIG. 13. 10... Composite material drilling drill, 11... Tip part, 1
1A...Primary cutting edge, 11B...Secondary cutting edge, 12...
-Shank part, 13...Twisted groove. Applicant's agent Sato - Ite 1 Figure 2 Figure 3 Figure 4 Figure 8 Figure 11

Claims (1)

[Claims] 1. A drill for drilling composite materials in which a twisted groove for discharging chips is provided from the tip of the drill to the vicinity of the shank, the drill tip having a predetermined tip angle. A composite material comprising a primary cutting edge having a tip shape, and a flat secondary cutting edge formed continuously with the primary cutting edge and having a tip angle smaller than the tip angle. Drill for drilling. 2. Continuing from the secondary cutting edge, an inclined tertiary cutting edge is formed in a stepped shape through a cutting edge portion that is approximately parallel to the axis, and this tertiary cutting edge has approximately the same tip angle as the secondary cutting edge. A drill for drilling composite materials according to claim 1, characterized in that it has the following. 3. Composite material drilling according to claim 1, wherein the primary cutting edge has a tip angle of about 90°, and the secondary cutting edge has a tip angle of about 20° to 30°. drill. 4. Maximum diameter d of the above primary cutting edge and maximum diameter D of the above secondary cutting edge
2. The drill for drilling composite materials according to claim 1, wherein the ratio d/D is set within a range of approximately 1/2 to 2/3. 5. The drill for drilling composite materials according to claim 1, wherein the relief angle of the secondary cutting edge is set within a range of approximately 20° to 25°.