JPH04348900A - Patch plate for drilling resin plate laminated with metal foil and method of drilling hole in resin plate laminated with metal foil - Google Patents

Abstract

PURPOSE:To reduce buckling of a metal foil laminated over a resin plate when a hole is drilled in the resin plate. CONSTITUTION:A thermoplastic resin plate 2 containing an inorganic filler is used as a patch plate for drilling hole in a stack of metal foil covered resin plates (copper foil covered epoxy resin laminated plates). Further, the drilling is made so as to the tip end of a drill 4 enters into the thermoplastic resin plate 1. The thermoplastic resin plate is polypropylene (resin/filler (weight part) = 100/20 to 400), high density polyethylene (100/10 to 400), ABS resin (100/10 to 250), polyethylene terephthalate (100/10 to 250) or the like.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a patch plate used for drilling holes in a metal foil-covered resin plate, such as a metal foil-covered thermosetting resin laminate, and a backing plate used for drilling holes in a metal foil-covered resin plate. Concerning how to do.

0002

[Prior Art] When manufacturing a printed circuit board in which printed circuits formed on both sides of an insulating layer made of a thermosetting resin laminate are electrically connected through holes in the insulating layer, double-sided metal foil is used as the material. There is a step of previously forming through holes in the stretched laminate by drilling. In this drilling process, several metal foil-covered laminates are stacked one on top of the other, and a phenolic resin laminate with a thickness of about 1.5 mm is used as a backing plate on the outside surface (usually the bottom surface) on the opposite side from the drill entry side. . Also,
0.5 mm on the outside surface (usually the top surface) on the entry side of the drill.
Generally, a thick aluminum plate is applied, and the hole is drilled by pressing down on the aluminum plate and its periphery. Then, in order to make good holes in all the metal foil-covered laminates, the tip of the drill was advanced to the phenolic resin laminate that served as the backing plate, and after stopping the advance once at the bottom dead center, the drill was moved back. There is.

[0003] Here, the reason why a phenol resin laminate is used as a backing plate is based on the following considerations. In other words, when drilling a hole, burrs appear on the metal foil around the hole, so in order to suppress this burr, the metal foil-covered laminate is firmly supported on the backing plate to prevent burrs from appearing. hardness and flatness are required. However, since the tip of the drill enters the caul plate, it is a result of consideration that the drill must not be so hard as to cause significant wear.

[0004] Also, like the phenolic resin laminate, the aluminum plate used for the holding plate suppresses the burrs of the metal foil around the hole, and also reduces the temperature of the drill by dissipating the frictional heat generated in the drill through thermal conduction. It also works to lower the

[0005]

[Problem to be solved by the invention] In the above conventional technology,
Viewed from the drill entry side, the finish on the top surface of the first metal foil-covered laminate becomes noticeably worse as the number of drill hits increases. The burrs of the metal foil around the drilled holes become large, and this causes a decrease in the continuity reliability when through-hole plating is performed. The problem to be solved by the present invention is to reduce the burr of metal foil when drilling holes in metal foil-clad resin plates such as metal foil-clad laminates, and to provide a backing plate for this purpose. An object of the present invention is to provide a drilling method.

[0006]

[Means for Solving the Problems] The caul plate according to the present invention includes:
It is made of a thermoplastic resin plate containing an inorganic filler and comes into contact with the metal foil-covered resin plate when drilling holes therein. Further, in the drilling method according to the present invention, a thermoplastic resin plate is installed on the outer surface of the drill on the side opposite to the entrance side, and the thermoplastic resin plate is brought into contact with the metal foil-covered resin plate, and a hole is drilled in the metal foil-covered resin plate. After the tip of the drill reaches the thermoplastic resin plate, the drill is moved back. A thermoplastic resin plate may be installed on the outer surface of the entry side of the drill so as to come into contact with the metal foil-covered resin plate, and a hole may be made in the metal foil-covered resin plate by penetrating the thermoplastic resin plate.

[0007]

[Function] Conventionally, drilling is performed while holding down a metal foil-covered resin plate, but this only holds down the surrounding area, and does not mean that the area to be drilled is sufficiently held down. Not exclusively. A small gap remains between the metal foil-covered resin plate and the aluminum plate. The chips generated during drilling are discharged along the spiral groove of the drill, and it is assumed that at this time, the chips enter the gap and further widen the gap, making the burr of the metal foil larger. .

However, in the case of the present invention described above, the amount of chips generated is reduced because the conventional phenolic resin plate is not used as the backing plate. When the tip of the drill enters the thermoplastic resin plate that serves as the backing plate, or when the drill penetrates the thermoplastic resin plate, the surrounding thermoplastic resin melts due to frictional heat, and this melts into the spiral groove of the drill. adhere to. This adhered molten resin captures the chips generated during drilling and rolls them into the molten resin, turning the molten state into large solid particles (similar to the shape of eraser scraps formed when using an eraser). ) is discharged from the spiral groove of the drill. Since these large chips are difficult to enter into the gap, the gap does not widen, and burrs of the metal foil can be suppressed.

In addition, when a conventional phenolic resin laminate is used as a backing plate, because it is hard, the drill tip reaches the bottom dead center and stops advancing until it retreats. By the way, the heat generation is most significant when the drill is rotating, which accelerates the wear of the drill. Wear of the drill is one of the causes of large burrs of the metal foil, but in the case of the present invention, even if the tip of the drill penetrates the thermoplastic resin plate, the heat generated is small, thereby reducing the wear of the drill. It will not be promoted. Furthermore, if drilling is continued with hard chips attached to the drill, the wear of the drill will be accelerated, but in the case of the present invention, the chips are captured by the molten thermoplastic resin and are not damaged. In this respect, the wear of the drill can also be suppressed.

It is important that the thermoplastic resin plate used as the patch plate contains an appropriate amount of inorganic filler. If the inorganic filler is not included, the molten resin attached to the drill will capture the chips and even after they are rolled up into the molten resin, they will not change from a molten state to a solid state and will remain attached to the spiral groove of the drill and be discharged. It may become difficult to clean or rub against the hole wall. The inorganic filler has the function of increasing the melt viscosity of the resin and reducing the absolute amount of the resin to be melted. In addition, by containing an inorganic filler, the surface of the thermoplastic resin plate becomes hard, allowing it to firmly hold down the metal foil-covered resin plate that is being drilled, and increases the thermal conductivity of the thermoplastic resin plate, making it easier to drill. It has the effect of absorbing heat and preventing the temperature of the drill from rising.

[0011] If the content of the inorganic filler is too high, the amount of molten resin will decrease and it will become difficult to capture the chips generated during drilling, causing the chips to separate between the metal foil-covered resin plate and the aluminum plate. It becomes easier to get into the gaps between metal foils, and the burrs of the metal foil gradually become larger. Further, when the tip of the drill penetrates into the thermoplastic resin plate, heat generation increases, which is undesirable because wear of the drill is accelerated. Adjust as appropriate depending on the type of thermoplastic resin used.

0012

[Example] Next, an example according to the present invention will be described. The thermoplastic resins to be used should not be used, except for those that thermally decompose at the temperature of the drill bit during drilling (estimated at 400°C) or those whose melt viscosity is too low and stick to the drill bit like syrup. It is not limited. polypropylene,
In addition to high-density polyethylene, ABS resin, and polyester, there are no particular problems with thermoplastic resins such as low-density polyethylene, polystyrene, polybutene, methyl methacrylate, polycarbonate, and thermoplastic elastomer. However, when the diameter of the drill becomes small, a large amount of frictional heat is generated and the drill blade tends to become particularly hot, so it is desirable that the melt viscosity of the resin be high. On the other hand, when molding a thermoplastic resin plate, the lower the melt viscosity, the better the moldability and the dispersibility of the inorganic filler, so these should be taken into consideration when making an appropriate selection.

The inorganic filler used may be general fillers such as calcium carbonate, magnesium carbonate, talc, mica, silica, alumina, aluminum hydroxide, magnesium hydroxide, barium sulfate, wollastonite, and radiolite. From the viewpoint of suppressing drill wear, inorganic fillers with low Mohs hardness, such as talc, barium sulfate, and aluminum hydroxide, are more preferable. In addition, in fillers containing water of crystallization, such as aluminum hydroxide and magnesium hydroxide, the water of crystallization is liberated by the heat generated by the drill, causing an endothermic reaction, which has the effect of preventing the temperature of the drill from rising. The average particle size of the inorganic filler is preferably 1 to 10 microns, and if the average particle size is 50 microns or more, the drill bit tends to chip (pitting).

Example 1 A polypropylene composition having the composition shown in Table 1 was extruded to form a thermoplastic resin plate 1 having a thickness of 1.5 mm.

[0015]

[Table 1]

Using the above-mentioned thermoplastic resin plate 1 as a backing plate, a metal foil-covered resin plate 2 with a structure as shown in FIG.
Drill holes with a diameter of 9 mm and a diameter of 1.2 mm were respectively made. The metal foil-clad resin board 2 on which holes are to be drilled is a composite double-sided copper-clad epoxy resin laminate (Shin-Kobe Denki Green Epo E668, 1.6 mm thick) that combines glass woven fabric and glass non-woven fabric as a base material. Stack 4 sheets, with the above thermoplastic resin plate 1 on the bottom surface and 0.5 m on the top surface.
An aluminum plate 3 having a thickness of m was installed. The drilling operation is carried out after the tip of the drill 4 that drilled the hole in the metal foil-covered resin plate 2 has entered the middle of the thermoplastic resin plate 1 in the thickness direction.
It was decided to move Drill 4 back.

FIGS. 2 and 3 show changes in the amount of burr of the copper foil as the number of drilling hits increases when the hole diameter is 0.9 mm and 1.2 mm. The amount of burr of the copper foil was measured on the top surface of the first metal foil-covered resin board 2 from the top and the bottom surface of the fourth metal foil-covered resin board 2 from the top. Also,
In the figure, in the conventional example, instead of the thermoplastic resin plate 2, a 1.6 m
This is a case where a phenolic resin laminate with a thickness of m is used as a backing plate. From each figure, it can be seen that in the case of using the patch plate of the example, although the copper foil burr may be slightly larger on the lower surface of the fourth sheet than the conventional example, the amount of copper foil burr including the top surface of the first sheet is small. It can be seen that the maximum value can be kept smaller than in the conventional example.

Example 2 Next, various thermoplastic resins (No. 1 to 4) shown in Table 2 were used.
Thermoplastic resin plates with a thickness of 1.5 mm were formed by extrusion molding with varying amounts of the inorganic filler (talc) contained. Drilling was performed in the same manner as in Example 1 for a case where the hole diameter was 0.7 mm. The amount of inorganic filler contained in the thermoplastic resin board (parts by weight relative to 100 parts by weight of resin), the top surface of the first composite double-sided copper-clad epoxy resin laminate from the top, and the fourth composite double-sided copper-clad laminate from the top. Amount of burr of copper foil on the bottom surface of the epoxy resin laminate (
(after 8000 hits) are shown in FIG. 4 and Table 3. Further, the degree of wear of the drill blade shown in Table 3 was determined by measuring the area of the cutting edge of the drill before and after drilling, and calculating it using the following formula.

[0019]

[Math 1]

[0020]

[Table 2]

[0021]

[Table 3]

From FIG. 4, according to the embodiment of the present invention,
It can be seen that in both cases, the maximum value of the amount of burr of the copper foil can be suppressed to be smaller than that of the conventional method. Also, from FIG. 4 and Table 3, resin 100
The preferred amount of the inorganic filler to parts by weight is 20 to 400 parts by weight for polypropylene, 10 to 400 parts by weight for high density polyethylene, and 10 to 400 parts by weight for ABS resin.
250 parts by weight, for polyethylene terephthalate, 10
-250 parts by weight, and it can be seen that the burrs of the copper foil are small as a whole, especially in polyethylene terephthalate.

Example 3 Talc was blended with 100 parts by weight of various thermoplastic resins shown in Table 2 in the proportions shown in Table 4, and 0.8 m thick was formed by extrusion molding.
A thermoplastic resin plate with a thickness of m was molded. This thermoplastic resin plate was used in place of the aluminum plate in Example 1, and the number of stacked composite double-sided copper-clad epoxy resin laminates was set to 3. Drill holes with a diameter of 0.4 mm were drilled. The degree of hole position shift during drilling is also shown in Table 4 in comparison with the case where an aluminum plate is used. Note that the amount of burr of the copper foil was small as in Example 1.

[0024]

[Table 4]

The drilling method according to the present invention is also effective when drilling holes in a single metal foil-covered resin plate. Further, the object to be drilled is not limited to the metal foil-clad laminate described above, as long as it is a metal foil-clad resin plate.

[0026]

[Effect of the invention] Conventionally, in order to reduce the burrs of metal foil, it was necessary to use a hard backing plate that could firmly support the metal foil-covered resin board, so phenolic resin laminates were used as backing boards. However, surprisingly, by using a softer thermoplastic resin plate as the backing plate, it became possible to suppress the burrs of the metal foil as a whole. As long as the amount of inorganic filler contained in the thermoplastic resin plate was not excessively increased, the degree of wear on the drill blade was reduced and the life of the drill was extended.

In addition, in the method according to the present invention, since the temperature rise due to frictional heat of the drill blade is small, a thermoplastic resin plate can be used as a holding plate instead of an aluminum plate for heat dissipation, and positional deviation during drilling can be avoided. will also become smaller.

[0028]Furthermore, the caul plate cannot be used any more because it creates a recess or a through hole when the tip of the drill enters, but the one according to the present invention is made of thermoplastic resin and cannot be melted. It can be remolded and reused, allowing for effective use of resources.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating an embodiment of the drilling method according to the present invention.

FIG. 2 is a curve diagram showing changes in the amount of burr of copper foil as the number of hits increases during drilling (hole diameter 0.9 mm).

FIG. 3 is a curve diagram showing changes in the amount of burr of copper foil as the number of hits increases during drilling (hole diameter 1.2 mm).

FIG. 4 is a curve diagram showing the relationship between the amount of inorganic filler contained in a thermoplastic resin plate and the amount of burr of copper foil of a metal foil-clad resin plate.

[Explanation of symbols]

1 is a thermoplastic resin plate 2 is a metal foil-covered resin board 4 is a drill

Claims (7)

[Claims] [Claim 1] A drill hole in a metal foil-clad resin plate, which is made of a thermoplastic resin plate containing an inorganic filler and is in contact with the metal foil-clad resin plate when drilling holes therein. Opening plate. 2. The drill hole in the metal foil-clad resin plate according to claim 1, wherein the thermoplastic resin is polypropylene, and the content of the inorganic filler is 20 to 400 parts by weight based on 100 parts by weight of the polypropylene. Opening plate. 3. The metal foiling resin according to claim 1, wherein the thermoplastic resin is high-density polyethylene, and the content of the inorganic filler is 10 to 400 parts by weight based on 100 parts by weight of the high-density polyethylene. A backing plate for drilling holes in a board. 4. The thermoplastic resin is ABS resin, and the content of the inorganic filler is 1 part by weight per 100 parts by weight of the ABS resin.
The caul plate for drilling a metal foil-clad resin plate according to claim 1, wherein the amount is 0 to 250 parts by weight. 5. The metal foil-clad resin plate according to claim 1, wherein the thermoplastic resin is polyethylene terephthalate, and the content of the inorganic filler is 10 to 250 parts by weight based on 100 parts by weight of polyethylene terephthalate. Backing plate for drilling holes. [Claim 6] When drilling holes in a metal foil-covered resin plate, a thermoplastic resin plate containing an inorganic filler is installed on the outer surface of the metal foil-covered resin plate on the opposite side to the entrance side of the drill. A method for drilling a hole in a metal foil-covered resin board, which comprises: abutting the metal foil-covered resin board, and then retracting the drill after the tip of the drill that drills a hole in the metal foil-covered resin board enters the thermoplastic resin board. [Claim 7] When drilling a hole in a metal foil-covered resin plate, a thermoplastic resin plate containing an inorganic filler is placed on the outer surface of the entry side of the drill, and the thermoplastic resin plate is brought into contact with the metal foil-covered resin plate. A method for drilling holes in a metal foil-covered resin board, which is characterized by drilling holes in the metal foil-covered resin board through the plastic resin board.