JP3054357B2 - Entry board for small diameter drilling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article which requires a high precision, such as a printed circuit board, having a diameter of 0.
This is an entry board used for drilling small diameter holes such as 1 mmφ to 2.0 mmφ. It suppresses the slip of the drill on the surface, improves the accuracy of the hole position, reduces breakage of the drill, and increases the copper foil of the printed wiring board. The present invention relates to a method for drilling a small-diameter hole on a high-quality and high-efficiency printed wiring board or the like by preventing damage such as damage to a product.

[0002]

2. Description of the Related Art Electronic technology includes computers such as telephones, TVs and personal computers, lighting equipment and other control devices in various manufacturing industries, as well as electric and communication fields, but also automobiles, home appliances, office equipment, cameras, toys, etc. It is applied to an extremely wide range, and is required to have higher functions and higher precision. With this, finer patterns, higher densities, and multilayer boards of printed wiring boards are rapidly progressing. As a result, the wiring width and the wiring interval of the printed wiring board are narrowed, and in particular, in a through-hole type printed wiring board, the number of holes is reduced and the number of holes is increased, and the position of the holes is also required to be more accurate. It is becoming. Conventionally, in the drilling of a multilayer board, small-diameter processing of 0.3 to 0.4 mmφ has been frequently performed.
Small diameter processing such as mmφ has been put to practical use, and it is considered that demands for reducing the diameter of holes, increasing the number of holes, and increasing the accuracy of hole positions will increase in the future.

In order to perform such small-diameter drilling,
Specifically, as shown in FIG. 2, if the entry board 1 is provided on the printed wiring board 5 and drilling is performed, the bite of the drill 8 is improved, and the position of the hole 9 provided in the printed wiring board 5 is improved. It has been known that the precision of the board can be improved and a hole can be formed so as not to cause burrs and burrs, and several proposals have been made for an entry board used for this. For example, a method of drilling a printed wiring board using an entry board in which both sides of a substrate made of wood pulp and glass fiber are sandwiched between aluminum foils or the like (Japanese Patent Laid-Open No. 61-61921), sandwiching both sides of an aluminum foil with paper A method of drilling a printed wiring board using an entry board (Japanese Patent Laid-Open No. 62-214000),
An entry board with an adhesive phase formed on one side of a metal foil,
There has been proposed an entry board such as a method in which the adhesive phase side is installed so as to face a printed wiring board and drilling is performed (Japanese Patent Application Laid-Open No. 63-11207).

[0004] However, in the invention described in Japanese Patent Publication No. 61-62121, the surface material of the entry board is 30
Since a hard material such as 03-H19 is used, the side slip of the drill is apt to occur, and the hole position accuracy is apt to be lowered. In addition, when an adhesive is used for manufacturing an entry board, the number of layers is five, and an increase in cost is inevitable. Japanese Patent Application Laid-Open No. 62-2140
In the invention of No. 00, the paper does not have heat resistance, and there is a great risk that paper powder is generated and causes a defect in a subsequent process such as plating. Furthermore, the invention of Japanese Patent Application Laid-Open No. 63-11207 has a problem because it is inevitable that chips are attached to the adhesive layer during drilling. As described above, although the conventional method still has a problem in drilling a small-diameter hole, furthermore, as the pattern of a printed wiring board is miniaturized, the diameter of a hole to be drilled is reduced, and the number of holes is increased. In spite of the demands for high-speed rotation of drills and thinner drills, the occurrence of shaking due to rotation has increased and the demands for reducing the hole position accuracy and the allowable height of burrs have been strict, Because we use the same entry board,
If the hole position accuracy becomes insufficient, if the hole position accuracy is improved, or if the burr generation is suppressed to less than the conventional level, there is a problem that the breakage of the drill increases.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the bite of the drill is good, the slip on the entry board surface of the drill is suppressed, the accuracy of the hole position is improved, and a workpiece such as a printed wiring board can be drilled at one time. An object of the present invention is to provide an entry board used for drilling a printed wiring board and the like and a method for drilling a small-diameter hole using the same, which can maintain a high number of sheets, reduce breakage of a drill, and further reduce occurrence of burrs. I do.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an entry board for drilling a small-diameter hole made of an aluminum foil composite material to which an aluminum foil or an aluminum alloy foil is bonded. Entry board for small-diameter drilling, characterized in that the hardness on the drilled side is smaller than the hardness of the aluminum foil or aluminum alloy foil having a thickness of 5 to 100 μm and a micro Vickers hardness (Hv) of 20 to 50. Entry board for small-diameter boring described above, wherein an aluminum foil or an aluminum alloy foil having a thickness of 30 to 200 μm and a micro Vickers hardness (Hv) of more than 50 and not more than 140 is bonded. Aluminum foil or aluminum alloy on the side The above-mentioned or the above-described entry board for small-diameter hole drilling and the drilling, wherein the foil surface is roughened so that the center line average roughness (Ra) of the surface becomes 0.15 to 0.30 μm. ,
A small-diameter printed wiring board characterized in that a hard surface of the entry board according to any one of the above or the above is arranged so as to be in contact with the printed wiring board on a plurality of printed wiring boards and drilled. The above problem was solved by developing a drilling method.

[0007]

FIG. 1 shows an outline of an entry board according to the present invention. The aluminum foil or aluminum alloy foil (hereinafter, both foils such as aluminum) used for the entry board of the present invention may be pure aluminum or an alloy component without any particular limitation. When it is used as an entry board for a hole drilling process, a foil such as aluminum on the drilled side [hereinafter referred to as aluminum foil (A)]. ] 2 is a foil such as aluminum on the drill exit side [hereinafter referred to as aluminum foil (B)]. ] The use of a composite material whose hardness is smaller than that of (4).

The material of the aluminum foil (A) 2 is preferably 1085, 1N30, 1
050, 1100, 3003, etc., from the viewpoint of rollability and that they are generally used as foils.
N30 and 3003 are more desirable. The thickness of the aluminum foil (A) 2 varies depending on the drill diameter used, but if it is thicker than necessary than the drill diameter, it is soft and sticks to the drill blade, so change the thickness according to the drill diameter. is necessary. Usually 5-100μ thick
m, the diameter is more preferably 5 to 50 μm when the drill diameter is 0.5 mm or less. The microfoil hardness (Hv) of the aluminum foil (A) 2 is 20 to 50, more preferably 25 to 40. Thus, it is necessary to soften the material to improve the biting of the drill. If the biting of the drill is good, it is possible to prevent the side of the drill bit from slipping, and the hole position accuracy is further improved. The aluminum foil (B) 4 is a foil having a thickness of 30 to 200 μm and a micro Vickers hardness (Hv) of more than 50, 140 or less, more preferably 65 to 140. By doing so, the height of burrs generated is smaller than in the conventional case, and can be suppressed to the same extent at worst.

The aluminum foil (A) 2 and the aluminum foil (B) 4 are bonded together with an adhesive 3 to form a composite material. In this case, the number of the aluminum foil (A) or the aluminum foil (B) is not limited to one as long as the aluminum foil (A) is arranged on the drill entry side and the aluminum foil (B) is arranged on the drill exit side. It may be a laminate of sheets.

As the adhesive 3, an adhesive which does not fuse due to heat generation during drilling, for example, a thermosetting acrylic, polyamide, rubber, epoxy or urethane adhesive is used. Urethane-based adhesives are preferred in terms of performance and cost. The thickness of the adhesive does not need to be limited, but is 1 to 5 g / m.
It is about ² , but when it is thicker, the cost increases.

The preferred range of the thickness of the entire composite material as the entry board 1 varies depending on the diameter of the drill 8. When the drill diameter is large, the thickness of the entry board is large, and when the drill diameter is small, the thickness is small. Drill diameter is 0.5mm
In the following cases, the thickness of the entire entry board is 3
It is about 0 to 200 μm, more preferably about 50 to 150 μm. Therefore, the thickness of the aluminum foil (B) is determined according to the aluminum foil (A) once it is determined.

The surface roughness of currently used aluminum foil for entry boards is usually the center line average roughness (Ra).
Is about 0.1 μm, and there is no problem if it is at the present level, but when it is required to drill a small-diameter hole of a higher-performance printed wiring board, if such flatness is obtained,
Even if the material of the aluminum foil (A) with which the drill first contacts is a soft material such as a micro Vickers hardness (Hv) of 20 to 50, when the drill comes into contact with a smooth surface during drilling, Since the tip slides easily, the hole position accuracy is apt to decrease. In order to prevent this side slip, the surface of the aluminum foil (A) of the entry board [the surface opposite to the side where the aluminum foil (B) is attached and on which the entry board drill is inserted] has a center line average roughness (Ra) of 0.15. It is preferable that the surface is roughened to a range of about 0.30 μm because it is effective in improving the hole position accuracy. When the center line average roughness (Ra) of the surface is smaller than 0.15 μm, the effect of preventing sideslip becomes insufficient, and 0.30 μm
If the roughness exceeds the limit, the load on the drill blade when the drill first comes into contact with the entry board increases, and the breakage of the drill increases, which is not preferable. When a plurality of printed wiring boards are stacked and drilled, if the position of the entry board is shifted, the teeth of the drill enter obliquely, so that the position of the lowermost hole of the printed wiring board is largely shifted. The difference in displacement of 5 μm in drilling small diameter holes is large, and the effect is large.

In the case where the hardness of the material of the entry board is high, it is effective in reducing the burr generation height. However, when the drill comes into contact with the entry board surface, the tip of the drill is liable to skid, and the hole is easily removed. Position accuracy decreases. On the other hand, when the hardness of the entry board is low, the centering accuracy of the drill can be ensured, but there is a problem in that the generation of burrs cannot be avoided. The present invention has been studied for the purpose of developing an entry board that solves these contradictory demands for preventing the sideslip of the drill to improve the hole positioning accuracy and for reducing the height of the burr generation, and for the purpose of developing an entry board. Sometimes, the aluminum foil (A) that the drill first contacts is made of a soft material to suppress the skid of the drill, and the aluminum foil (B), which is harder than this material, is bonded to a material that can suppress the occurrence of burrs. By developing an entry board, the above conflicting demands have been solved together.

As a result, it has been possible to meet the demands for improving the accuracy of the hole position of the printed wiring board in which the pattern is sharply miniaturized, suppressing the generation height of burrs, and reducing the number of drill breakage accidents. At the same time, since the burr generation height is small, the number of printed wiring boards that can be punched at one time can be increased, so that productivity can be increased. It also enables prevention of damage to copper foil for circuit formation such as wiring boards, etc.
A greatly improved entry board and a method for drilling a small-diameter hole in a printed wiring board using the same have been developed.

(Example) As an aluminum foil (A),
1N30 O material and H14 material of thickness shown in Table 1 and 300
3, using an O material having a thickness shown in Table 1 and using an H18 material or H19 material of 3003, 3004, and 5182 as an aluminum foil (B), using a composite material having a combination shown in Table 1 as an entry board, Its performance was evaluated. For drilling, a glass-epoxy 6-layer plate having a thickness of 1.6 mm was used. From the drill bit side, [Entry board / glass-epoxy 6-layer plate / 2 sheets / thickness 1.
6 mm paper-phenol laminated board (backup board)], and drilling was performed under the following conditions using a perforated pile having a configuration of stacking. Drill bit 0.35mm width Rotation speed 80000rpm. Feed speed 1.6 mm / min. For comparison, conventionally used 1100-H
18, 3003-H18 aluminum foil alone was used as the entry board.

The center line average roughness (Ra) of the surface of the entry board, the hardness of the aluminum foil (A) and the aluminum foil (B) used for each entry board, the hole position accuracy after drilling, and the height of burrs The values obtained are shown in the table. Micro Vickers hardness (Hv) is a dynamic ultra-micro hardness tester (DUH-201) by Shimadzu Corporation
5 gf load, 5 seconds holding time, load speed
It was measured at 0.3375 gf / sec.

[0017]

[Table 1]

[0018]

The entry board of the present invention uses an aluminum or other foil composite material in which a soft aluminum foil (A) and a harder aluminum foil (B) are bonded together as an entry board for small-diameter drilling. That is. As a result, since the main body is an aluminum foil, the drill has a cleaning effect and is excellent in diffusion of heat generated during drilling. Because a soft material was used for the aluminum foil (A),
The drill bites well on the surface, suppresses the skid of the drill, improves the accuracy of the hole position, effectively suppresses the drill runout due to the rotation caused by the thinness of the drill, significantly reduces the breakage, and aluminum foil Since the generation of burrs is suppressed by using a material having high hardness in (B), there is no problem even if the number of workpieces that can be processed at a time is increased, and high productivity and high burr generation It is effective to prevent the copper foil for circuit formation of the printed wiring board from being damaged,
Disconnection of a circuit due to miniaturization of a pattern can be effectively prevented. When drilling a small-diameter hole in a printed wiring board using such an entry board, highly accurate drilling can be performed with high productivity. Furthermore, the center line average roughness (Ra) of the drilled side surface of the entry board is 0.1
By setting the thickness to 5 to 0.30 μm, the hole position accuracy can be further improved.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of an entry board for drilling a small-diameter hole according to the present invention.

FIG. 2 is a schematic view of a conventional method for making a small-diameter hole in a printed wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Entry board for small diameter drilling 2 Aluminum foil (A) 3 Adhesive 4 Aluminum foil (B) 5 Printed wiring board 6 Backup board 7 Spindle 8 Drill 9 Hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-261699 (JP, A) JP-A-60-155307 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B26F 1/16 B23B 35 / 00,41 / 00 H05K 3/00

Claims (4)

(57) [Claims] 1. A small-diameter hole entry board made of an aluminum foil composite material to which an aluminum foil or an aluminum alloy foil is bonded, wherein the hardness of the aluminum foil or the aluminum alloy foil is compared with the hardness of the drill exit side. An entry board for small-diameter drilling, characterized by reduced hardness on the entry side. 2. An aluminum foil or an aluminum alloy foil having a thickness of 5 to 100 μm and a micro Vickers hardness (Hv) of 20 to 50, and a thickness of 30 to 200 μm and a micro Vickers hardness (Hv) of more than 50 and 140 or less. 2. The small-diameter hole drilling entry board according to claim 1, wherein an aluminum foil or an aluminum alloy foil is bonded. 3. The surface of the aluminum foil or aluminum alloy foil on the drilled side of the entry board is subjected to a surface roughening treatment so that the center line average roughness (Ra) of the surface is 0.15 to 0.30 μm. The entry board for drilling a small-diameter hole according to claim 1 or 2. 4. When drilling, the surface of the entry board according to any one of claims 1 to 3 having high hardness is arranged on a plurality of printed wiring boards so as to be in contact with the printed wiring board, and drilling is performed. A method for drilling a small-diameter hole in a printed wiring board. 』