JPS5933546Y2 - Drill for drilling composite materials - Google Patents

Description

[Detailed description of the invention] The present invention relates to a drill for drilling a composite material made of laminated cloth, impregnated with resin, and cured.
When drilling a composite material containing a fibrous structure, the fibers B of the composite material B are pulled up at the corner A of the drill A, as shown in Figure 1, and the stretched fibers B' are used as the secondary cutting edge. Since the hole is cut at a sharp angle, the cut end of the perforated part becomes fluffy, making it difficult to obtain roundness.

Further, at the final stage of drilling, it is difficult to cut the fibers B sharply, and there is a lot of fiber fluff, especially on the back surface of the formed hole, resulting in a state where the fiber fluff is raised around the periphery of the hole.

If countersunking is allowed, the fuzz at the hole opening can be removed by secondary processing with a countersunk drill, but if countersunking is not allowed, there is no other way but to cut it off with a file or knife, which is extremely time-consuming. It takes.

The above-mentioned fuzziness becomes even more severe as the fibers become stronger, but this is especially the case with aramid (aromatic polyamide) fiber resin hardening materials, which have been developed in recent years and are now used as main parts of aircraft. (trade name: Keppra, manufactured by DuPont) has extremely strong fibers, and when used in the drilling process when used as aircraft parts,
The above-mentioned fuzziness is extremely noticeable, and not only does it make it difficult to obtain a perfectly round hole, but the fuzziness of the hole opening (especially the hole opening on the back side) causes it to stand up on the mounting surface, which is a problem. In order to prevent this, the back side of the material must be made of glass cloth with little fuzz, and then the holes are punched. He had a dog problem.

The present invention provides a drill that can accurately drill holes in composite materials containing the above-mentioned fibrous structure without creating fluff.
The embodiments shown in FIGS. 2 to 5 will be described below to solve the above-mentioned conventional problems.

As shown in FIGS. 2 to 5, the drill according to the present invention has a centering cutting edge 1° provided at the center of the tip, and a tip edge provided on both sides of the circumferential surface centered on the center of the centering cutting edge 1. Due to the main cutting edge 2 having an arcuate crescent shape and the cutting edge 3 formed between the centering cutting edge 1 and the base of the main cutting edge 20, the frontal shape of the tip of the drill is L-shaped as shown in FIG. It is configured in an M-shape.

Reference numeral 4 denotes an escape groove formed on the outer circumferential surface of the drill body above the cutting edge 3 so as to be parallel to the axis of the drill body and facing directly upward.

According to the present invention, in which the main cutting edge 2 having a predetermined width d is formed around the centering cutting edge 1 and having a predetermined width d along the circumferential surfaces on both sides of the centering cutting edge 1 as described above, the composite material is When drilling holes in the fibers, the main cutting edge 2 has a cutting edge that matches the rotation locus of the drill and is formed in a crescent shape that is arcuate in the rotational direction, so the cutting edge cuts off the fibers in a way that strokes them. The centering cutting blade 1 and the cutting blade 3 cut sequentially from the center toward the outer periphery between the parts cut off by the main cutting blade 2 from the center (.

Therefore, the inner peripheral surface of the hole that is cut off from above by the main cutting blade 2 becomes a sharp cut surface, and not only is there no fuzz, but also the hole opening on the back side is cut sharply, so the hole on the back side is cut sharply. Conventional problems such as fluff protruding from the mouth are completely prevented.

Also, the relief groove 4 formed on the outer peripheral surface of the drill body is connected to the cutting edge 3.
It is formed parallel to the axis directly upward from the main cutting edge 2.
Since the upper outer circumferential surface part is formed in the same arcuate surface part 5 as the main cutting edge 2 without a relief groove, there is no risk that the core part 5 will catch the cut fiber end and make it fluffy. The arcuate surface portion 5 prevents the drill from wobbling and allows a clean hole to be made without distortion.

As described above, according to the present invention, it is possible to sharply perforate composite materials containing strong fibers without creating fluff, and it is possible to perform efficient and accurate perforation using a portable tool without a guide. It is extremely effective.

[Brief explanation of drawings]

Figure 1A2 is an explanatory diagram showing sequentially the drilling process of a composite material using a conventional general drill, Figures 2 to 5 show an embodiment of the present invention, and Figure 2 is an overall front view; Figure 3 is an enlarged detailed view of the X part in Figure 2, Figure 4 is a side view of Figure 3, and Figure 5 is a side view of Figure 3.
The figure is a front end view of FIG. 2. 1... Centering cutting edge, 2... Main cutting edge, 3... Cutting edge, 4... Relief groove,
5... Arc-shaped surface.

Claims (1)

[Scope of utility model registration request] A centering cutting edge is provided in the center, and a nearly crescent-shaped main cutting edge is formed on the left and right circumferential arc surfaces of the centering cutting edge, the tip of which forms an arc with respect to the surface to be drilled, and a cut is made between the centering cutting edge and the main cutting edge. The blades are formed so that they have a substantially M-shaped cutting edge shape when viewed from the front, and an relief groove is formed on the outer peripheral surface of the drill body above the cutting blade and parallel to the axis of the drill body. A drill for drilling composite materials, characterized in that the outer circumferential surface of the drill body above the main cutting edge is formed into the same circular arc surface as the outer circumferential surface of the main cutting edge.