JP2000015632A - Method for boring prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for boring a prepreg with a backing impregnated with a thermosetting resin composition in which boring can be done many times continuously with the use of a drill bit. SOLUTION: A prepreg 20 is bored with the use of a drill bit 10 which has a blade 12 at the end part and a notch shaped recessed part 18 communicating with a prepreg in the axial direction from a noncontact part to a blade 12 part in boring in a shaft part 14 and in which a through hole 16 in the axial direction is exposed to the recessed part 18, while the blade 12 and the shaft part 14 being cooled by ejecting gas A from the through hole 16 to the blade 12 part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drilling a prepreg used for manufacturing a laminate.

[0002]

2. Description of the Related Art Conventionally, a laminated board used in the production of a printed wiring board is impregnated with a thermosetting resin composition such as an epoxy resin, which is impregnated into a base material having voids such as a glass cloth. The cured thermosetting resin composition is semi-cured (B
After preparing a prepreg by solidifying into a (stage) shape, and then stacking the required number of prepregs, and arranging a metal foil such as a copper foil on one or both sides thereof as necessary, forming a laminate It is manufactured by molding the laminate by heating and pressing.

[0003] Since the prepreg is obtained by impregnating a thermosetting resin composition into a substrate and semi-curing the resin, the resin decreases in viscosity as soon as it is heated, and flows when it is further heated. It shows the behavior that it does not flow. Therefore, it is easy to handle because it is semi-cured when handling at the time of lamination, and has a certain degree of fluidity during molding by heating and pressing, so that even if there is some variation in the amount of resin, the thickness is almost uniform Is generally used because of the feature that a laminated plate of

However, in the case of manufacturing a laminate using a prepreg, when the viscosity of the resin is reduced by heating, the prepreg is displaced by the flow of the resin, and a laminate having a desired size cannot be obtained. There was a problem that sometimes. Therefore, a hole is formed in the prepreg in advance,
A method generally called a pin lamination method, in which a pin is inserted into the hole to heat and mold the prepreg in a fixed state, is also performed.

Conventionally, as a method of forming a hole in the prepreg, as shown in FIG. 3, a prepreg is formed by using a drill bit 40 having a blade 42 at a tip end and a twist groove 44 on a side surface of a shaft. 2. Description of the Related Art A method of forming a hole in a load of a plurality of prepregs by drilling has been performed. However, in the case of this method, when the temperature of the drill bit 40 gradually increases due to repeated drilling and exceeds the melting point of the resin, a large amount of the resin adheres to the blade 42 and the torsion groove 44, and the drill bit is removed. There is a problem that the load on the spindle and the like of the machine becomes large and it becomes difficult to make a hole, and the number of times that a hole can be made continuously is small.

For this reason, a drill bit 50 having a blade 52 at the tip and a hole 54 penetrating in the axial direction as shown in FIGS.
As shown in (c), a method is being considered in which gas A is blown out from the penetrating hole 54 to the blade 52 to cool the blade 52 while drilling a load on the prepreg 20. FIG. 4B is a view of the drill bit 50 of FIG. 4A as viewed from the side. However, even in the case of this method, the improvement of the number of times that drilling can be continuously performed is insufficient, and a method of drilling a prepreg that can frequently perform drilling continuously is desired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to use a drill bit to apply a thermosetting resin composition to a substrate. An object of the present invention is to provide a method for drilling a prepreg in which a plurality of impregnated prepregs are drilled in a pile of prepregs in which a plurality of impregnated prepregs are stacked.

[0008]

According to a first aspect of the present invention, there is provided a prepreg drilling method using a drill bit having a blade at a tip end and having a hole penetrating in the axial direction. In the prepreg boring method, in which a plurality of prepregs impregnated with a thermosetting resin composition are impregnated into a base material while blowing a gas to the blade portion, a drill bit is drilled when the prepreg is pierced. The shaft portion has a cutout-shaped concave portion communicating in the axial direction from the non-contact portion to the blade portion, and the through-hole is exposed in the concave portion.

According to a second aspect of the present invention, there is provided a prepreg drilling method according to the first aspect, wherein the drill bit is a single-flute drill bit.

According to a third aspect of the present invention, there is provided the prepreg drilling method according to the first or second aspect, wherein the blade of the drill bit has an axial portion closer to a shaft portion of a portion supporting the blade. Are protruded in the radial direction by 0.2 to 1 mm.

According to the present invention, the gas blown out from the through hole reaches the blade portion and the lower surface side of the load of the prepreg via the recess, and also reaches the upper surface side of the load of the prepreg. Therefore, the entire portion of the drill bit that comes into contact with the prepreg can be cooled by the gas, and the chips generated by cutting the prepreg can be efficiently discharged by the gas, so that the drill bit can be cut. Powder and resin are less likely to adhere to the prepreg, and the prepreg drilling method is excellent in the number of times that drilling can be continuously performed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for drilling a prepreg according to the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining an embodiment of a prepreg drilling method according to the present invention, wherein (a) is a front view showing a drill bit to be used, and (b).
FIG. 2 is a side view showing a drill bit to be used, and FIG. 2C is a front view showing a state in which a drill bit is drilled. FIG.
FIG. 4 is a front view showing a drill bit used in another embodiment of the prepreg drilling method according to the present invention.

One embodiment of the method for drilling a prepreg according to the present invention has a blade 12 at a tip end and a shaft 14 in the direction of the shaft as shown in FIGS. 1 (a) and 1 (b). It has a notch-shaped recess 18 communicating therewith, and the recess 1
8 uses a drill bit 10 in which a hole 16 penetrating in the axial direction is exposed.

In the case of drilling, FIG.
As shown in (c), the through hole 16 is inserted into the recess 18.
While the gas A is blown out to the blade 12 through the hole, the load of the prepreg 20 is perforated. At this time, the depth of the cut is set so that the upper portion of the concave portion 18 is held in a state of protruding above the load of the prepreg 20, and the concave portion 1 formed in the drill bit 10 is formed.
Reference numeral 8 denotes a concave portion 18 which communicates in the axial direction from a portion not in contact with the load of the prepreg 20 to a portion of the blade 12 when drilling.

Therefore, the gas A blown out from the through hole 16 reaches the blade 12 and the lower surface side of the load of the prepreg 20 via the concave portion 18 and also reaches the upper surface side of the load of the prepreg 20. I do. Therefore, the entire part of the drill bit 10 that comes into contact with the prepreg 20 can be cooled by this gas, and the drill bit 1 can be cooled.
0 can be kept low, so drill bit 1
It is difficult for the molten resin to adhere to zero, and the number of times that drilling can be continuously performed is increased. Further, since the chips generated by cutting the prepreg 20 with the gas A can be efficiently discharged, the chips are less likely to adhere to the drill bit 10, and the drilling is continuously performed. The number of operations that can be performed is increasing.

The size of the recess 18 is determined by the size of the through hole 1.
The size of the shaft A is not particularly limited as long as the gas A blown out from the cylinder 6 can reach the blade 12 and the lower surface side or the upper surface side of the load of the prepreg 20 via the recess 18. When about half of the portion 14 is notched, the number of continuous drilling operations is particularly excellent, which is preferable.
If the size is too small, the gas A becomes difficult to pass, so that the number of times that drilling can be continuously performed may decrease. If the size is too large, the strength of the drill bit 10 tends to decrease.

The concave portion 18 has a notched shape, but this is not limited to the shaft portion 14 previously formed in a cylindrical shape and cut out therefrom. It may be formed by casting such that Further, the shape of the cutout is not limited to the cutout having a D-shaped cross section, and the cutout portion may have a curved shape or an uneven line shape, or may have a plurality of cutout portions. In the case of the drill bit 10 in which the notched portion is one drill bit 10 and the drill bit 10 having one blade 12 formed at the tip of the notched portion, the strength and the passage of the gas A are obtained. The balance of ease is excellent and preferable.

As shown in FIG. 2, the blade 12 is disposed so as to protrude 0.2 to 1 mm as a length L in the radial direction of the shaft portion 14 from the shaft portion 14 which supports the blade 12. When the prepreg 20 is provided, the gas A passes through the gap between the shaft portion 14 and the prepreg 20 caused by the protrusion of the blade 12 when the prepreg 20 is pierced. The number of times that this can be continuously performed is excellent and preferable.

The material of the blade 12 is as follows.
4 may be formed of the same material, or may be formed of a different material and joined together. For example, quenched iron, super hard stainless steel, diamond, or the like is generally used. . In addition, when it is formed of diamond or formed of a composite material having a diamond layer formed on the surface, the number of times that drilling can be continuously performed is particularly excellent.

The diameter of the drill bit 10 may be adjusted according to the size of the hole to be formed, but is generally about 3 to 10 mm. The number of revolutions and the feed rate at the time of drilling are appropriately adjusted according to the appearance of the drilled hole and the like, and drilling is performed.

The gas A blown out from the through hole 16
In general, air is used, but carbon dioxide gas or the like may be blown out. In addition, when the gas A is subjected to the cooling treatment, the temperature of the drill bit 10 becomes particularly difficult to rise, so that the number of times that the drilling can be continuously performed is particularly excellent and preferable. Also, if this gas A is subjected to dehumidification processing,
Since the moisture absorption of the prepreg 20 at the time of drilling can be reduced, the characteristics of the laminate manufactured using the prepreg 20 are excellent and preferable.

The prepreg 20 used in the present invention comprises:
The thermosetting resin composition is obtained by impregnating a base material.For example, the thermosetting resin composition is impregnated by immersing the base material in a varnish having a viscosity adjusted with a solvent, and then dried by heating if necessary. The semi-cured or manufactured at room temperature, the liquid or heat-melted liquid thermosetting resin composition, after applying to one surface of the substrate, heated to reduce the viscosity and impregnated It is obtained. The resin ratio of the prepreg 20 is
It is generally 40 to 200 parts by weight based on 100 parts by weight of the total of the thermosetting resin composition and the base material.

The thermosetting resin composition used for the prepreg 20 includes epoxy resin, phenol resin,
The thermosetting resin composition in its entirety can be used, such as a polyimide resin, an unsaturated polyester resin, a polyphenylene ether resin, or the like alone, a modified product, or a mixture.
The thermosetting resin composition contains a thermosetting resin as an essential component and, if necessary, a curing agent for the thermosetting resin,
A curing accelerator and an inorganic filler can be contained.

The base material used for the prepreg 20 is a woven fabric, nonwoven fabric, paper, or the like of inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl, and polyimide, and natural fibers such as cotton. Can be. In addition, it is preferable to use a woven fabric (glass cloth) made of glass fiber because the obtained laminate has excellent heat resistance and moisture resistance.

The load of the prepreg 20 is not particularly limited as long as a plurality of the prepregs 20 are stacked, and a plastic plate or the like may be stacked above, below, or between them as necessary.

[0026]

(Embodiment 1) As a drill bit, as shown in FIG. 1, a notch-shaped concave portion 18 communicating with the shaft portion 14 in the direction of the axis is provided on the shaft portion 14 in addition to having a blade 12 at a tip portion. A drill bit 10 having a diameter of 6 mm in which a hole 16 penetrating in the axial direction was exposed in the concave portion 18 was used. The blade 12 of the drill bit 10 is formed by a single diamond blade, and the size of the concave portion 18 is a drill bit 10 in which approximately half of the shaft portion 14 has a cutout shape.

A glass cloth (substrate) impregnated with an epoxy resin-based resin composition as a prepreg has a thickness of 0.1%.
mm prepreg [R16, manufactured by Matsushita Electric Works, Ltd.
61] was used. Then, 50 prepregs were stacked to form a load of the prepreg 20.

Then, using the above drill bit 10,
Drilling was performed on the load of the prepreg 20 at a feed rate of 20 seconds / hit while blowing dehumidified air through the hole 16 penetrating the load of the prepreg 20. At this time, the upper part of the recess 18 is
So that it is held in a state protruding above the load of
By setting the depth of cut, drilling was performed by adjusting the concave portion 18 so that it communicated in the axial direction from the portion not in contact with the load of the prepreg 20 to the portion of the blade 12 when drilling. As a result, pitching occurred on the blade 12 when drilling was performed continuously for 10,000 hits, making drilling difficult.

(Embodiment 2) As a drill bit, as shown in FIG.
Has a notch-shaped concave portion 18 communicating with the direction of the axis, a hole 16 penetrating in the axial direction is exposed in the concave portion 18, and the blade 12 has a shaft that supports the blade 12. Drilling was performed in the same manner as in Example 1 except that a drill bit 10 having a diameter of 6 mm was provided so as to protrude from the part 14 by 0.5 mm in the radial direction of the shaft part 14. As a result, when 23,000 hits were continuously drilled, blade 1
Pitching occurred in No. 2, making drilling difficult.

(Comparative Example 1) As shown in FIG. 4, a drill bit 50 having a diameter of 6 mm and having a blade 52 at the tip and a hole 54 penetrating in the axial direction as shown in FIG.
The hole was drilled in the same manner as in Example 1 except that the load on the prepreg 20 was drilled while blowing the dehumidified air through the hole 54 through which the air was blown.
In this case, as shown in FIG. 4C, the shaft of the drill bit 50 has penetrated to the inside of the load of the prepreg 20, and the gas A blown out from the through hole 54 is
The prepreg 20 did not reach the upper surface of the load. As a result, pitching occurred in the blade 52 when drilling was performed continuously for 5,000 hits, making drilling difficult.

(Summary of Results) It was confirmed that, in each of the examples in which the prepreg was drilled according to the present invention, the number of times of continuous drilling was excellent as compared with Comparative Example 1. Further, in the second embodiment, in which the blade is disposed so as to protrude from the shaft portion of the portion supporting the blade in the radial direction of the shaft by 0.2 to 1 mm, the drilling is particularly continuous compared to the first embodiment. It was confirmed that the number of times that it could be performed was excellent.

[0032]

According to the method for drilling a prepreg according to the present invention, the drill bit used has a notch-shaped concave portion communicating in the axial direction from a portion not in contact with a load of the prepreg to a blade portion when drilling. Since the drill bit has a shaft portion and a through hole that blows out gas into the concave portion is exposed, the method is a method for drilling a prepreg excellent in the number of times that drilling can be continuously performed.

[Brief description of the drawings]

FIG. 1 is a view for explaining an embodiment of a prepreg drilling method according to the present invention, wherein (a) is a front view showing a drill bit to be used, (b) is a side view showing a drill bit to be used, and (c). () Is a cutaway front view showing the state of drilling.

FIG. 2 is a front view showing a drill bit used in another embodiment of the prepreg drilling method according to the present invention.

FIG. 3 is a front view showing a drill bit used in a conventional prepreg drilling method.

4A and 4B are diagrams illustrating another conventional prepreg drilling method, wherein FIG. 4A is a front view showing a drill bit to be used, FIG. 4B is a side view showing a drill bit to be used,
(C) is the figure which fractured and showed the state which perforated.

[Explanation of symbols]

 10, 40, 50 Drill bit 12, 42, 52 Blade 14 Shaft 16, 54 Hole penetrating 18 Recess 20 Prepreg A Gas

Claims (3)

[Claims] 1. A thermosetting resin composition is formed on a base material by using a drill bit having a blade at a tip portion and having a hole penetrating in an axial direction, while blowing gas from the penetrating hole to a blade portion. In a method of drilling a prepreg loaded with a plurality of prepregs impregnated with a prepreg, a drill bit is formed so that when drilling, a cutting portion communicating in the axial direction from a portion not in contact with the prepreg loaded material to a blade portion. A method for drilling a prepreg, characterized in that the drill bit is a drill bit having a notch-shaped concave portion in a shaft portion and exposing the through hole in the concave portion. 2. The method for drilling a prepreg according to claim 1, wherein the drill bit is a single-flute drill bit. 3. The drill bit according to claim 1, wherein a blade of the drill bit protrudes from a shaft portion of a portion supporting the blade by 0.2 to 1 mm in a radial direction of the shaft. 2. The method for drilling a prepreg according to 2.