JP2000061990A - Method and apparatus for injection-molding case for memory card having ultrathin part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a case for constituting a memory card having an ultrathin part 0.7 mm or below in thickness surely, and to mold the ultrathin part to be free from residual stress and damage. SOLUTION: A case for a memory card in which an ultrathin part for installing microminiaturized electronic parts such as IC chips being protected from external moisture and others is molded integrally with other parts by using a synthetic resin is injection-molded. In this process, when a synthetic resin is injected into a cavity, with one surface of a degassing vent 40 of three- dimensional structure which has a suction chamber 41 communicating with a degassing circuit 50 nearly in the middle exposed to a part corresponding to the ultrathin part of a case of the cavity formed by an injection molding apparatus, residual air and generated gas is extracted through the suction chamber 41 of the degassing vent 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method and apparatus, and more particularly to a method and apparatus suitable for injection molding a memory card case which is a resin molded product having an ultrathin portion.

[0002]

2. Description of the Related Art In recent years, electronic devices have been rapidly developed, and an audio device 300 for music such as that shown in FIG. 1 has been developed. The audio device 300 shown in FIG. 1 is used by inserting a very small and thin memory card 200, so that audio data recorded in the memory card 200 can be read and heard by an earphone or the like. It is a device. The memory card 200 used in the audio device 300 is a kind of recording medium called an IC card, a stick memory card, a smart card, or the like, and has a micro IC chip (electronic component) inside. Is incorporated.

The memory card 200 is, for example, a device in which music data is converted into a binary signal and recorded in an IC chip. Of course, the data recorded in this kind of memory card 200 is rewritable, and it is possible to record a popular song at that time or a song read from a compact disc in a length of about 40 minutes. Is.

The small memory card 200 equipped with such an IC chip is very thin because it is inserted / removed into / from the small main body 300 side in order to rewrite or "exchange" data. actually,
It has a thickness of about 2 to 3 mm and a size as shown in FIG. In addition, such a memory card 200
Since it has an IC chip inside, it must have sufficient durability against moisture and dirt, and it can be used by holding it by hand and pulling it out of the device 300 or the data input device. Therefore, it is necessary to have a certain degree of rigidity to facilitate the handling. Therefore, this type of memory card 200
It is necessary to form it as a synthetic resin, and it is necessary to protect the internal IC chip.

If such a memory card 200 is to be formed of synthetic resin, it is necessary to devise a method for ensuring a storage place for the IC chip and sufficiently protecting the IC chip from moisture and the like. It is natural. In conclusion, this memory card 200 is made into a case, and the IC chip is mounted in this case. However, the whole thickness is about 2 to 3 mm, and the IC chip is When trying to secure a storage space while protecting from moisture, it is necessary to form an ultra-thin portion in the case.

Injection molding is the only method for forming a case having an ultrathin portion with a synthetic resin. In particular, since this type of memory card 200 must have an external connection terminal for electrically connecting to the main body side, as shown in FIGS. 1 and 2, this external connection terminal portion is also a case. In order to preform it on the side, it is inevitable to rely on injection molding in which a molten resin material is forcedly injected into the cavity.

What is important in an injection molding method or an injection molding apparatus for forming a resin molded product having the same shape as the cavity by forcibly injecting the melted resin material into the cavity is that the resin material melted in this cavity is important. Is to be completely filled. Therefore, in this type of injection molding method or apparatus for molding the memory card 200, which is a resin molded product, an "injection mold casting machine" is disclosed, for example, in Japanese Patent Laid-Open No. 5-31563. It is conceivable to adopt the method and apparatus for degassing in the mold.

The degassing method and apparatus disclosed in Japanese Unexamined Patent Publication No. 5-31563 are as follows: "The conventional degassing in the die in the injection type die casting machine is to remove the gas from the cavity between the upper and lower dies. A gas venting slit (hereinafter referred to as a slit) having a thickness of about 0.2 mm is formed so as to emit gas spontaneously. When the molten metal moves at a relatively high speed, such as when the molten metal is injected into the injection sleeve or when the molten metal is injected from the injection sleeve into the mold cavity,
There is a limit to venting the gas so as to eliminate the back pressure in the cavity, so that the amount of hot water supply fluctuated and gas defects were found in the obtained casting. Further, if many slits are provided in order to easily reduce the back pressure, a problem of wiping with water may occur. Focusing on the point, "The clogging of the gas vent due to the release agent sprayed when opening and closing the mold is minimized,
The object of the present invention is to provide a method and a device for degassing the inside of a die of an injection-type die casting machine, which can degas the inside of the die cavity by suction without any problem.

Further, in the gas venting method and apparatus disclosed in the above publication, a gas cylinder is attached to a gas vent slit formed between a movable die and a fixed die of a die, and
To this gas cylinder, from the electromagnetic three-way valve, through the electromagnetic three-way valve, to the suction device, and to the high-pressure air line via the electromagnetic three-way valve, connect the high-pressure air line by operating the electromagnetic three-way valve when opening the mold, and at the same time when the mold clamping starts By operating the electromagnetic three-way valve and, a certain amount of primary suction is performed so that the back pressure during hot water supply is zero, and after the injection tip closes the hot water supply hole, secondary suction is performed to further increase the suction amount. " It is considered that the adoption of such a configuration exerts the effect of "increasing the uniformity of product quality and obtaining a cast product in which gas defect generation is prevented".

However, according to the study by the present inventors, in the above method and apparatus, for example, FIGS.
It was found that the memory card 200 having the ultrathin portion 202 as shown in FIG. The ultra-thin portion 2 of the memory card 200 shown in FIGS.
Reference numeral 02 denotes a portion on which the above-mentioned IC chip is mounted and which protects this IC chip from moisture and dirt from the outside, and moreover does not have a bad influence on the inside IC chip even if it is touched by the outside. This ultra-thin portion 202 has a thickness of 0.7 mm or less, as described above.
It must be a very thin wall.

In addition, in the memory card 200 as shown in FIGS. 1 to 4, it is usually necessary to simultaneously form not only the ultrathin portion 202 but also a non-thin portion. This is because it is not possible to make the memory card 200 having the necessary functions only with the ultra-thin portion 202. In the case of the memory card as shown in FIGS. 1 to 4, the front and back cases are integrated. This is because a portion for exposing the external connection terminal is also required.

When the memory card 200 having the ultra-thin portion 202 as described above is to be injection-molded by the conventional degassing method, even if the portion other than the ultra-thin portion 202 is sufficiently degassed. , Ultra-thin portion of cavity 2
It means that you can not fully degas the part that becomes 02,
It is almost impossible to inject the resin material into the portion that will be the ultra-thin portion 202 of this cavity. In particular, such a memory card 200 can be used for a short time (for example, ten seconds or more).
Molding inside was almost impossible with the prior art.

Therefore, when the present inventors perform injection molding of the memory card 200 having the ultra-thin portion 202 of 0.7 mm or less, it is necessary to ensure that the resin material sufficiently reaches the ultra-thin portion 202. As a result of various studies on what to do, the present invention has been completed.

[0014]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and an object to be solved is a memory card having an ultrathin portion 202 having a wall thickness of 0.7 mm or less. Case 21 for configuring 200
It is an object of the present invention to provide an injection molding method and an injection molding apparatus capable of reliably manufacturing 0 and molding the ultrathin portion 202 without any residual stress or damage.

[0015]

In order to solve the above-mentioned problems, first, the means adopted by the invention according to claim 1 will be described with the reference numerals used in the description of the embodiments described later. "The ultra-thin portion 202 for mounting ultra-small electronic components such as IC chips protected from external moisture,
A cavity 30 formed by the injection molding apparatus 100 when injection molding the memory card case 210 integrally formed with other parts using synthetic resin as a material.
In a portion of the case 210 corresponding to the ultra-thin portion 202, a suction chamber 41 communicating with the gas vent circuit 50 is provided substantially in the center, and one surface of the gas vent vent 40 having a three-dimensional mesh structure is exposed. For the memory card having the ultra-thin portion 202, the residual air and the generated gas in the cavity 30 are extracted through the suction chamber 41 of the gas venting vent 40 when the synthetic resin is injected into the cavity 30. The method of injection molding the case 210. "

That is, in the injection molding method of the memory card case 210 according to the first aspect, the case 210 and the ultra-thin portion 202 thereof are surely molded while adopting a large frame portion of a general injection molding technique. 11 and FIG. 1 for that purpose.
A gas venting vent 4 having a suction chamber 41 as shown in FIG.
I decided to use 0.

The degassing vent 40 is formed of, for example, a so-called sintered metal which is obtained by pressing and burning fine metal powder, and a ventilation passage having a three-dimensional mesh structure is formed therein. It is what Therefore, one surface of the gas venting vent 40 is exposed in the cavity 30, and the gas venting circuit 50 is provided in one suction chamber 41 formed substantially at the center of the gas venting vent 40.
By connecting the above, the gas generated when the air in the cavity 30 or the synthetic resin material is melted can be easily discharged to the outside through the suction chamber 41 of the gas vent vent 40. . Of course, the surface of the gas venting vent 40 exposed in the cavity 30 is changed according to the shape and size of the ultrathin portion 202. Case 210 shown
You may make it arrange | position in the whole.

The degassing vent 40 is exposed at one portion of the cavity 30 where the ultra-thin portion 202 must be formed in the case 210, and vice versa. When degassing is performed through the degassing circuit 50 from the suction chamber 41 that is open to the surface, the entire exposed surface of the degassing vent 40 in the cavity 30 is for degassing air and gas in the cavity 30. Is meant to be. That is, air or gas is sucked into the suction chamber 41 on the surface of the degassing vent 40.
There are many small "suction holes" for passing the inside, but these suction holes do not let the molten resin, which is more viscous than air or gas, pass through. The degassing vent 40 enables the molten resin to flow to all the locations in the cavity 30.

Therefore, according to the injection molding method of the first aspect, the air remaining in the cavity 30 or the gate 31 is fed from the portion corresponding to the ultra-thin portion 202 of the cavity 30. Gases such as gas can be sent to the degassing circuit 50 side together in the suction chamber 41, and even if the portion corresponding to the ultra-thin portion 202 of the cavity 30 is very thin, It is possible to reliably generate the flow of the molten resin. Therefore, according to the injection molding method of the first aspect, the case 210 having the complete ultra-thin portion 202 can be reliably manufactured.

In order to solve the above-mentioned problems, the means adopted by the invention according to claim 2 is the same as in the injection molding method according to claim 1, in which the groove aligning portion 60 surrounding the cavity 30 is injection-molded. It is formed on the parting line surface of the device 100 and the airtight state is maintained at the groove-matching portion 60 so that the cavity 30 and the outside are shielded from each other. "

That is, in the injection molding method according to the second aspect of the present invention, the gas such as the air from the outside is prevented from flowing into the cavity 30 in order to further ensure the degassing from the degassing vent 40. For that purpose, as shown in FIGS. 11 and 12, the groove alignment portion 60 surrounding the cavity 30 is formed on the parting line surface of the injection molding apparatus 100.

Therefore, according to the injection molding method of the second aspect, it is possible to ensure the degassing of the degassing vent 40, and the case 21 having the complete ultrathin portion 202.
0 can be reliably manufactured.

In order to solve the above-mentioned problems, the means adopted by the invention according to claim 3 is as follows.
Similarly, regarding the injection molding method according to (1), "the degassing circuit 50 is made to communicate with the outside of the cavity 30".

That is, in the injection molding method according to the third aspect of the present invention, the gas such as the air from the outside is prevented from flowing into the cavity 30 in order to further ensure the degassing from the degassing vent 40. For that reason, the degassing circuit 50 is made to communicate with the outside of the cavity 30.

Therefore, according to the injection molding method of the third aspect, it is possible to ensure the degassing of the degassing vent 40, and the case 21 having the complete ultra-thin portion 202.
0 can be reliably manufactured.

In order to solve the above-mentioned problems, means adopted by the invention according to claim 4 is the same as in the injection molding method according to any one of claims 1 to 3, in which "the resin is injected into the cavity 30. That is, it is controlled by the resin pressure in the portion immediately before the cavity 30. "

That is, in the injection molding method according to the fourth aspect of the present invention, as shown in FIG. 6, in the injection molding apparatus 100 for carrying out this, a pressure sensor 70 for detecting the pressure of the molten resin from the gate 31. Is arranged almost immediately before each cavity 30, and the resin injection timing is adjusted by the signal from the pressure sensor 70. As a result, the molten resin can be effectively filled into the cavity 30, which is a very small space, and wasteful use of the material can be prevented.

Therefore, according to the injection molding method of the fourth aspect, the amount of resin used and the ultra-thin portion 20 of the cavity 30 are used.
The resin flow to the portion corresponding to 2 can be adjusted well, and the case 210 having the complete ultrathin portion 202 can be reliably manufactured.

In order to solve the above-mentioned problems, the means adopted by the invention according to claim 5 is the injection molding method according to any one of claims 1 to 4, When taking out the card case 210, the memory card case 210 and its runner portion 220 are separated from each other. "

Generally, an injection-molded resin product must be taken out of the mold, but the resin remaining in the resin is cured and the runner portion 220 is formed between the gate 31 and each cavity 30. To be done. Since the runner portion 220 is a wasteful portion of the case 210 attached to the outside of the product, the runner portion 220 is separated at the same time when the case 210 is taken out from the cavity 30.

Therefore, according to the injection molding method of the fifth aspect, it is possible to mold the case 210 without waste of steps. Of course, the injection molding method according to claim 5 relates to the injection molding method according to any one of claims 1 to 4, so that the case 210 having the complete ultra-thin portion 202 can be secured. Needless to say, it can be manufactured.

In order to solve the above-mentioned problems, the means adopted by the invention according to claim 6 is the same as that of the injection molding method according to any one of claims 1 to 5. That is, the concave portion 203 is formed at a position where the tip of the runner portion 220 is located to ensure separation from the runner portion 220. ”

Various forms of the case 210 are conceivable, but in the present invention, as shown in FIG. 2 and the like, a recess is formed in the memory card case 210 at the position where the tip of the runner portion 220 is located. 203 is formed. As a result, in the molding method according to the sixth aspect, due to the existence of the recess 203, the runner portion 2
It is easy to insert a cutting blade 81 or the like for separating from the case 20, and a case 21 having a complete ultra-thin portion 202.
0 can be reliably manufactured.

In order to solve the above-mentioned problems, the means adopted by the invention according to claim 7 is the same as in the injection molding method according to any one of claims 1 to 6. Stored in the vacuum tank 90,
That's the molding work. "

If the injection molding apparatus 100 is arranged in the vacuum tank 90, the invasion of the outside air into each cavity 30 is prevented, so that the degassing vent 40 in the cavity 30 can surely degas. Done Therefore, according to the molding method of the seventh aspect, the case 210 having the complete ultra-thin portion 202 can be reliably manufactured.

Although the above is the description relating to the injection molding method, the following relates to the injection molding apparatus 100 for specifically carrying out each of the above molding methods. That is, in order to solve the above-mentioned problems, the means adopted by the invention according to claim 8 will be described with reference to the reference numerals used in the description of the embodiments described later. Injection-molding apparatus for injection-molding a memory card case 210 made of a synthetic resin integrally molded with other parts, and an ultra-thin part 202 for protecting and mounting the same from outside moisture etc. 100, one side of the gas vent vent 40 having a three-dimensional mesh structure is exposed at a portion of the cavity 30 formed thereby corresponding to the ultra-thin portion 202 of the case 210. A suction chamber 41 communicating with the degassing circuit 50 is formed at substantially the center of the chamber 40. When the synthetic resin is injected into the cavity 30, the suction chamber 41 of the degassing vent 40 is used to close the chamber. The injection molding apparatus of memory card case 210 having a super thin portion 202, characterized in that to obtain extraction of residual air and gases generated tee 30 1
00 ”.

That is, in the injection molding apparatus 100 for the memory card case 210 according to the eighth aspect, the case 210 and its structure are adopted while adopting the structure of a general injection molding apparatus as in the injection molding method described above. The ultra-thin portion 202 can be surely molded, and for that purpose, the degassing vent 40 having the suction chamber 41 as shown in FIGS. 11 and 12 is used. is there.

The gas venting vent 40 has one surface exposed in the cavity 30 and the periphery of the gas venting vent 40 is wrapped by the base of the upper mold 10 or the lower mold 20. 41 is formed. Then, the degassing circuit 50 shown in FIGS. 7 and 8 is connected to the suction chamber 41. A large number of small “suction holes” for passing air or gas into the suction chamber 41 are opened on the surface of the gas vent vent 40, and these suction holes are made of molten resin having a higher viscosity than air or gas. It does not pass. Of course, the surface of the degassing vent 40 exposed in the cavity 30 is changed according to the shape and size of the ultrathin portion 202, but if possible, it is shown in FIGS. 2 and 3. Case 2
You may make it located in 10 whole.

The degassing vent 40 as described above has one surface exposed at an important portion in the cavity 30 where the ultra-thin portion 202 must be formed in the case 210, and vice versa. When degassing is performed through the degassing circuit 50 from the suction chamber 41 that is open to the surface, the entire exposed surface of the degassing vent 40 in the cavity 30 is for degassing air and gas in the cavity 30. Is meant to be. That is, the degassing vent 40 enables the molten resin to flow to all the locations in the cavity 30.

Therefore, the injection molding apparatus 10 according to the eighth aspect of the present invention.
According to 0, air remaining in the cavity 30 from the portion corresponding to the ultra-thin portion 202 of the cavity 30 or gas such as gas sent from the gate 31 is collected in the suction chamber 41. Since the gas can be sent to the gas vent circuit 50 side, even if the portion corresponding to the ultra-thin portion 202 of the cavity 30 is very thin, the flow of the molten resin there can be reliably generated. Of. Therefore, according to the injection molding apparatus 100 of the eighth aspect, the case 210 having the complete ultra-thin portion 202 can be reliably manufactured.

The means adopted by the invention according to claim 9 is, in the injection molding apparatus 100 according to claim 8 described above, that "the cavity 30 is formed on the parting line surface of the injection molding apparatus 100.
Forming a groove-matching part 60 surrounding the
The airtightness maintaining member 61 such as vacuum grease is applied or fitted to 0 to isolate the cavity 30 from the outside. "

That is, in the injection molding apparatus 100 according to the ninth aspect, as shown in FIGS. 11 and 12, the groove aligning portion 60 surrounding the cavity 30 is formed on the parting line surface of the upper mold 10 or the lower mold 20. Then, an airtightness maintaining member 61 such as vacuum grease is applied to the groove-matching portion 60, or an airtightness maintaining member 61 such as silicon packing or rubber packing is fitted to block the cavity 30 from the outside. It is the one.

That is, the injection molding apparatus 1 according to claim 9
In order to further ensure the gas release from the gas release vent 40, the groove alignment portion 60 surrounding the cavity 30 is formed on the parting line surface of the injection molding apparatus 100.

Therefore, the injection molding apparatus 10 according to the ninth aspect of the present invention.
According to 0, gas such as air from the outside is
Inside the cavities 30 by the gas vent vent 40, and the case 210 having the complete ultra-thin portion 202 can be reliably manufactured. You can do it.

The means adopted by the invention according to claim 10 is the injection molding apparatus 1 according to claim 8 or claim 9.
00, "The degassing circuit 50, the cavity 30
I made it communicate with the outside. "

That is, in the injection molding apparatus 100 according to the tenth aspect of the present invention, in order to make the degassing from the degassing vent 40 more reliable, a gas such as air from the outside does not flow into the cavity 30. It was done,
Therefore, as shown in FIG.
Is communicated with the outside of the cavity 30.

Therefore, the injection molding apparatus 1 according to the tenth aspect of the present invention.
According to 00, the degassing of the degassing vent 40 can be ensured, and the case 210 having the complete ultrathin portion 202 can be reliably manufactured.

In order to solve the above-mentioned problems, the means adopted by the invention according to claim 11 is the injection molding apparatus 100 according to any one of claims 8 to 10,
“A pressure sensor 70 for detecting the resin pressure is arranged immediately before the cavity 30, and the timing of resin injection into the cavity 30 is controlled by a signal from the pressure sensor 70.”

That is, in the injection molding apparatus 100 according to the eleventh aspect of the present invention, as shown in FIG. 6, the pressure sensor 70 for detecting the pressure of the molten resin from the gate 31 is arranged almost immediately before each cavity 30. This pressure sensor 7
The signal from 0 was used to adjust the resin injection timing. As a result, the molten resin can be effectively filled into the cavity 30, which is a very small space, and wasteful use of the material can be prevented.

Therefore, the injection molding apparatus 1 according to the eleventh aspect of the present invention.
00, the amount of resin used and the resin flow to the portion corresponding to the ultra-thin portion 202 of the cavity 30 can be adjusted well, and the case 210 having the complete ultra-thin portion 202 can be reliably manufactured. Can be done.

Further, the means adopted by the invention according to claim 12 is the same as in the case of the injection molding apparatus 100 according to any one of claims 8 to 11, wherein "the memory card case 210 of the injection molding apparatus 100 and A cutting blade 81 that cooperates with the rod 80 that pushes out the product is provided between the tip of the runner portion 220 connected to the memory card case 210, and when the memory card case 210 is taken out from the injection molding apparatus 100, the cutting card 81 uses the memory card case 210. And the runner part 220 thereof can be separated from each other. "

That is, in this injection molding apparatus 100,
As shown in FIG. 6, a cutting blade 81 in a direction orthogonal to the cavity 30 is provided between the memory card case 210 and the tip of a runner portion 220 connected to the case 210 so as to be vertically movable. The cutting blade 81 is designed to co-operate with a rod 80 for pushing out a product, and when the memory card case 210 is taken out from the injection molding apparatus 100 by the rod 80, the cutting blade 81
The memory card case 210 and the runner portion 220 are separated from each other.

Therefore, the injection molding apparatus 1 according to the twelfth aspect of the present invention.
According to 00, the case 210 can be molded without waste of steps. Of course, since the injection molding apparatus 100 according to claim 12 is related to the injection molding apparatus 100 according to any one of claims 8 to 11, the case 210 having the complete ultra-thin portion 202. Needless to say, can be reliably manufactured.

The means adopted by the invention according to claim 13 is the same as that of the injection molding apparatus 100 according to any one of claims 8 to 12, wherein "the entire injection molding apparatus 100 is in the vacuum tank 90". Be stored in. "

If the injection molding apparatus 100 is placed in the vacuum tank 90, the outside air is prevented from entering the cavities 30. Therefore, the degassing vent 40 in the cavities 30 can surely release the gas. Done Therefore, according to the injection molding apparatus 100 of the thirteenth aspect,
The case 210 having the complete ultra-thin portion 202 can be reliably manufactured.

[0056]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the invention of each claim constructed as described above will be explained based on the embodiment shown in the drawings. The injection molding apparatus 100 shown as the embodiment is
Since the injection molding method according to claims 1 to 7 is embodied, the injection molding apparatus 100 will be mainly described below.

FIG. 1 shows an injection molding apparatus 10 according to the present invention.
A memory card 20 constructed as a very small and thin one using a case 210 injection-molded by
0, an audio device 300 for music or the like into which the memory card 200 is inserted is shown. The audio device 300 shown in FIG. 1 is a device in which audio data recorded therein is read from the inserted memory card 200 and is heard by an earphone or the like. The memory card 200 used in the audio device 300 is a kind of recording medium called an IC card, a stick memory card, a smart card, or the like, and has a micro IC chip (electronic component) inside. Is incorporated.

This memory card 200 is formed by adhering two kinds of cases 210 shown in FIGS. 2 and 3, and a part or the whole thereof is a “dot” in FIGS. 2 and 3. The ultra-thin portion 202 indicated by is formed. The specific thickness of the ultrathin portion 202 in the present embodiment is 0.15 mm to 0.25 mm. Electronic components are mounted on the ultra-thin portion 202.
One of the cases 21 is used to connect the mounted electronic components to the outside.
It is designed to be made from the comb tooth portion 201 formed in 0. The form of each case 210 may be, for example, as shown in FIG. 4, but in the following description of the embodiments, the form shown in FIGS.

5 and 6 show a cross section of the injection molding apparatus 100 according to the present invention. In this injection molding apparatus 100, the upper part approximately 1/4 is the upper mold 10 and the lower part thereof. A boundary between the part and the lower die 20 is a horizontal parting line PL. The gate 31 into which the molten resin is injected is located at the center of the upper end of the drawing, and is provided on both sides of the intersection of the vertical axis of the gate 31 and the parting line PL, as shown in FIG. A cavity 30 is formed.

The entire injection molding apparatus 100 is inserted into a vacuum tank 90 shown by the one-dot chain line in FIG. 6, and the inside of the vacuum tank 90 is kept at a constant negative pressure by a vacuum pump or the like (not shown). Will be done. As described above, by arranging the injection molding apparatus 100 in the vacuum tank 90, the invasion of the outside air into each cavity 30 is prevented, so that the degassing by the degassing vent 40 in the cavity 30 described later is sure. As a result, the case 210 having the complete ultra-thin portion 202 can be reliably manufactured.

In addition, the injection molding apparatus 100 adopts the structure of an injection molding apparatus which has been generally used in the past as a major part of the structure, but the case 2
In order to reliably mold 10 and its ultra-thin portion 202, a degassing vent 40 having a suction chamber 41 as shown in FIGS. 11 and 12 is used. .

The gas vent vent 40 has one surface exposed in the cavity 30 and the periphery of the gas vent vent 40 is wrapped by the base of the upper mold 10 or the lower mold 20. 41 is formed. Then, the degassing circuit 50 shown in FIGS. 7 and 8 is connected to the suction chamber 41. A large number of small “suction holes” for passing air or gas into the suction chamber 41 are opened on the surface of the gas vent vent 40, and these suction holes are made of molten resin having a higher viscosity than air or gas. It does not pass. Of course, the surface of the degassing vent 40 exposed in the cavity 30 is changed according to the shape and size of the ultrathin portion 202, but if possible, it is shown in FIGS. 2 and 3. Case 2
You may make it located in 10 whole.

The degassing vent 40 is formed of, for example, a so-called "sintered metal" in which fine metal powder is pressed and solidified, and a ventilation passage having a three-dimensional mesh structure is formed therein. It has been done. That is, a large number of small "suction holes" for passing air or gas into the suction chamber 41 are opened on the surface of the gas vent vent 40, but the suction holes are larger than air or gas. It is impermeable to the highly viscous molten resin, and as a result, the degassing vent 40 enables the molten resin to flow to all the locations in the cavity 30.

The gas vent vent 40 is provided in the cavity 3
One surface is exposed in an important portion in 0 where the ultra-thin portion 202 must be formed in the case 210. And this vent vent 4
On the surface opposite to 0, a suction chamber 41 communicating with the degassing circuit 50 and opening is provided as shown in FIGS. 11 and 12.
Has been formed. The degassing vent 40 is such that, when degassing is performed from the suction chamber 41 through the degassing circuit 50, the entire exposed surface of the degassing chamber 41 degass the air and gas inside the cavity 30. That is, the degassing vent 40 is a gas such as the gas remaining from the portion corresponding to the ultra-thin portion 202 of the cavity 30 in the cavity 30 or the gas generated from the molten resin fed from the gate 31. Can be collectively sent to the degassing circuit 50 side in the suction chamber 41, and even if the portion corresponding to the ultra-thin portion 202 of the cavity 30 is very thin, the flow of the molten resin there. Can be reliably generated.

Further, in this injection molding apparatus 100, as shown in FIG.
As shown in FIGS. 1 and 12, a groove matching portion 60 surrounding the cavity 30 is formed on the surface of the parting line PL, and an airtightness maintaining member 61 such as vacuum grease is applied to the groove matching portion 60. Alternatively, an airtightness maintaining member 61 such as silicon packing or rubber packing is fitted to block the cavity 30 from the outside.

Further, in this injection molding apparatus 100, as shown in FIG.
It is also connected to outside 0. As a result, in the injection molding apparatus 100, the gas such as air from the outside is not generated in the cavity 3
The gas is prevented from flowing into 0, so that the gas can be more reliably discharged from the gas discharge vent 40.

Further, in this injection molding apparatus 100, the pressure sensor 7 for detecting the resin pressure immediately before the cavity 30 is used.
0 is arranged, and the timing of resin injection from the gate 31 into the cavity 30 is controlled by the signal from the pressure sensor 70. In other words, the pressure sensor 70 controls the driving of a molten resin supply device such as a spreader (not shown), and is provided with a pressure switch or the like at the lower end of the rod that moves down by receiving the pressure in the cavity 30, for example. is there.

That is, in this injection molding apparatus 100,
As shown in FIG. 6, a pressure sensor 70 for detecting the pressure of the molten resin from the gate 31 is provided in each cavity 30.
It is arranged almost immediately before, and the timing of resin injection is adjusted by a signal from the pressure sensor 70. This allows the cavity 3 to be a very small space.
It is possible to effectively fill the molten resin in 0, and prevent wasteful use of materials.

Furthermore, this injection molding apparatus 100 is shown in FIG.
As shown in FIG. 3, a cutting blade 81 that cooperates with the rod 80 that pushes out the product is provided between the memory card case 210 and the tip of the runner portion 220 that is continuous with the memory card case 210. When taking out the memory card case 210, the memory card case 210 and its runner portion 220 are cut by the cutting blade 81.
It separates and.

That is, in this injection molding apparatus 100,
As shown in FIG. 6, a cutting blade 81 in a direction orthogonal to the cavity 30 is provided between the memory card case 210 and the tip of a runner portion 220 connected to the case 210 so as to be vertically movable. The cutting blade 81 is designed to co-operate with a rod 80 for pushing out a product, and when the memory card case 210 is taken out from the injection molding apparatus 100 by the rod 80, the cutting blade 81
The memory card case 210 and the runner portion 220 are separated from each other.

[0071]

As described above in detail, in the present invention,
The case 210 for constructing the memory card 200 having the ultra-thin portion 202 having a wall thickness of 0.7 mm or less is reliably manufactured by the configuration as described in the above embodiment. Thus, it is possible to provide the injection molding method and the injection molding apparatus which can mold the ultra thin portion 202 without any residual stress or damage.

[Brief description of drawings]

FIG. 1 is a perspective view showing a usage state of a memory card configured by using a case formed by a method or an injection molding device according to the present invention.

FIG. 2 is an enlarged plan view of one case that constitutes the memory card.

FIG. 3 is an enlarged plan view of the other case constituting the memory card.

FIG. 4 is an enlarged plan view showing another embodiment of the case constituting the memory card.

FIG. 5 is a vertical sectional view of an injection molding apparatus according to the present invention.

6 is a vertical cross-sectional view of the injection molding apparatus shown in FIG. 5 seen from the center.

FIG. 7 is a plan view of a lower mold forming the injection molding apparatus.

8 is an enlarged plan view showing the cavity shown in FIG. 7 and its surroundings.

9 is a partial bottom view of the cavity on the upper die side corresponding to FIG. 8;

10 is a partial vertical cross-sectional view taken along line 1-1 in FIGS. 8 and 9. FIG.

11 is an enlarged cross-sectional view of the gas vent vent taken along line 2-2 in FIG.

12 is a cross-sectional view of the degassing vent as seen along line 3-3 in FIG.

[Explanation of symbols]

100 injection molding equipment 10 Upper mold 20 Lower mold 30 cavities 31 gate 40 degassing vent 41 Suction chamber 50 degassing circuit 60 Groove alignment part 61 Airtightness maintaining member 70 Pressure sensor 80 Extruded rod 81 cutting blade 90 vacuum tank 200 memory card 201 Comb teeth 202 Ultra thin wall 203 recess 210 cases 220 runner part 300 audio equipment

Claims (13)

[Claims] 1. A case for a memory card in which an ultra-thin portion for mounting an ultra-small electronic component such as an IC chip protected from external moisture and the like is integrally molded with other portions by using a synthetic resin as a material. In injection molding, the cavity formed by the injection molding device has a suction chamber communicating with the degassing circuit at a portion corresponding to the ultra-thin portion of the case, and has a three-dimensional mesh structure. When the synthetic resin is injected into the cavity with one surface of the gas vent vent exposed, residual air or generated gas in the cavity is extracted through a suction chamber of the gas vent vent. An injection molding method for a memory card case having a meat portion. 2. A groove matching portion surrounding the cavity,
Formed on the parting line surface of the injection molding device,
The case for a memory card having an ultra-thin portion according to claim 1, characterized in that the groove and the outside are kept airtight to block the cavity from the outside. Injection molding method. 3. The method of injection molding a case for a memory card having an ultra-thin portion according to claim 1, wherein the degassing circuit is made to communicate with the outside of the cavity. . 4. The ultra-thin portion according to any one of claims 1 to 3, wherein the resin injection into the cavity is controlled by the resin pressure in the portion immediately before the cavity. Injection molding method for a case for a memory card having a. 5. The memory card case and the runner portion thereof are separated from each other when the memory card case is taken out from the injection molding device. An injection molding method for a case for a memory card having the described ultra-thin portion. 6. A recess for ensuring separation from the runner portion is formed at a location of the tip of the runner portion of the memory card case. An injection molding method for a memory card case having an ultrathin portion according to any one of claims 1 to 5. 7. The ultrathin body according to claim 1, wherein the entire injection molding apparatus is housed in a vacuum tank and the molding operation is performed. An injection molding method for a memory card case having a meat portion. 8. A memory card made of a synthetic resin which is integrally molded with another portion of an ultra-thin portion for mounting an ultra-small electronic component such as an IC chip while protecting it from external moisture. An injection molding device for injection-molding a case for use, wherein one side of a gas venting vent having a three-dimensional mesh structure is exposed at a portion of a cavity formed by the case corresponding to an ultra-thin portion of the case. At the same time, a suction chamber communicating with the gas vent circuit is formed substantially in the center of the gas vent vent, and when the synthetic resin is injected into the cavity, residual air or generation in the cavity is passed through the suction chamber of the gas vent vent. An injection molding device for a case for a memory card having an ultra-thin portion, characterized in that gas can be extracted. 9. A groove aligning portion that surrounds the cavity is formed on a parting line surface of the injection molding device, and an airtightness maintaining member such as vacuum grease is applied to or fitted in the groove aligning portion, and the cavity and the external portion. 9. The injection molding device for a case for a memory card having an ultra-thin portion according to claim 8, characterized in that it is cut off. 10. The injection molding apparatus for a case for a memory card having an ultra-thin portion according to claim 8, wherein the degassing circuit is communicated with the outside of the cavity. 11. A pressure sensor for detecting the resin pressure is arranged immediately before the cavity, and the timing of resin injection into the cavity is controlled by a signal from the pressure sensor. Item 8 to Claim 1
An injection molding device for a case for a memory card having the ultra-thin portion according to any one of 0. 12. A cutting blade that cooperates with a rod for pushing out a product is provided between the memory card case of the injection molding device and a tip of a runner portion connected to the memory card case. The memory having an ultra-thin portion according to any one of claims 8 to 11, wherein the memory blade case and its runner portion can be separated by the cutting blade when the memory case is taken out. Card case injection molding equipment. 13. The memory card having an ultra-thin portion according to claim 8, wherein the entire injection molding device is housed in a vacuum tank. Case injection molding equipment.