JPH0939057A - Injection molding mold apparatus and cartridge shell injection molding method - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a mold device for injection molding capable of achieving highly accurate flatness of a shell of a cartridge having a thin and uneven wall thickness, and an injection molding method of the shell of the cartridge. SOLUTION: In a mold device for injection molding for injection molding a shell 1 or 2 of a cartridge for containing a recording medium, a first mold 20 and a first mold 2 are provided.
And a second mold 30 forming a cavity C for injecting a molding material to form a shell 1 or 2 of the cartridge between 0 and 0, and a shell 1 or 2 of the cartridge formed in the cavity C. The flatness adjusting means 40 for adjusting the flatness of the shell 1 or 2 of the cartridge by applying a compressive force to the predetermined portions P1 to P6 of 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die apparatus for injection molding a cartridge shell for accommodating a recording medium and a method for injection molding a cartridge shell.

[0002]

A shell of a cartridge for accommodating a recording medium, for example, a magneto-optical disk (mini disk MD)
The cartridge of No. 1 includes an upper shell 1 shown in FIG. 9 and a lower shell 2 shown in FIG. This type of magneto-optical disk is housed in the upper shell 1 of FIG. 9 and the lower shell 2 of FIG. 10. For example, a shutter is automatically opened / closed in the magnetic recording / reproducing apparatus to form a magneto-optical disk. On the other hand, it is possible to record signals and reproduce signals from the magneto-optical disk. The window 3 of the upper shell 1 is a window for the overwrite magnetic head of the magneto-optical disk recording / reproducing apparatus, and the window 4 of the lower shell 2 is a window for the optical pickup.

The shell of the cartridge for accommodating the recording medium is made to be as thin as possible in order to make the cartridge smaller and thinner, and the windows 3 and 4 described above are required. Therefore, the most important item functionally in the molded product of the upper shell 1 and the lower shell 2 of the shell is the flatness (warp) of the shell. This flatness is also an important factor from the viewpoint of the rotating operation of the disk substrate in the shell and the functional aspect after inserting the hardware. Fig. 9 shows the cartridge shell of the current Mini Disc.
The upper shell 1 and the lower shell 4 in FIG. 10 are configured by a combination of two shells, and the flatness standard of both the upper shell 1 and the lower shell 2 is required to have an accuracy of the order of 1/100 mm. FIG. 11 shows the warp direction of such a shell. FIG. 11A shows a state of being warped to the positive side, and FIG. 11B shows a state of being warped in the negative direction. The warp of the upper shell 1 in FIG. 9 is preferably, for example, less than or equal to 0.1 mm, and the warp of the lower shell 2 is preferably 0 mm (ie, flat), and the accuracy of the flatness of the lower shell 2 is more severe.

The upper shell 1 and the lower shell 2 of this kind are generally formed by injection molding of a synthetic resin such as a polycarbonate resin acrylonitrile butadiene styrene copolymer resin (ABS resin). The molding flow of this injection molding includes a plasticizing step, an injection step, a pressure holding step, and a cooling step. The plasticizing step is a step of melting the molding resin agent, and the injection step is a step of injecting the molten resin into the mold. The pressure holding step is a step of compensating for deformation and the like while the molten resin is not solidified. Further, the cooling step is a step of solidifying the molded product until it has sufficient strength at the time of mold release. The molded product molded by this is taken out by opening the mold, and the series of steps described above are repeated by closing the mold, so that the upper shell 1 and the lower shell 2 can be continuously molded and manufactured. it can.

[0005]

However, the adjustment of the flatness of the upper shell 1 and the lower shell 2 of the current cartridge is performed by the pressure holding step in the above-mentioned injection molding step. As described above, the pressure holding step is a step of compensating for the deformation of the molded product, and the flatness of the upper shell 1 or the lower shell 2 is adjusted and maintained by adjusting the control of the pressure holding and the pressure holding time.

FIG. 9 shows flatness measurement points P4, P5 and P6 of the upper shell 1, and FIG.
3 shows flatness measurement points P1, P2, P3.
That is, each of the upper shell 1 and the lower shell 2 is provided with three flatness measurement points. In the current injection molding, the flatness measurement point P4 of the upper shell 1 and the flatness measurement point P2 of the lower shell 2 are the points at which flatness is the most difficult to obtain. The upper shell 1 and the lower shell 2 are both product shapes having thin and uneven thickness. The tendency of the flatness of the upper shell 1 and the lower shell 2 by adjusting the pressure holding condition is that the flatness of the upper shell 1 shows a negative warp in FIG. Since the flatness of the shell tends to move to the positive warpage in FIG. 11A by increasing the holding pressure, the flatness tendency of the upper shell 1 and the lower shell 2 causes the holding pressure condition in the flatness adjustment. When the width becomes very small and the appearance of the molded product becomes inconvenient, it is difficult to drastically change the molding conditions.

Further, both the upper shell 1 and the lower shell 2 transmit a constant holding pressure to a space for forming a molded product, that is, a cavity, but since the shell shape has a thin uneven thickness, the shell flatness is Differences can be seen at each of the flatness measurement points P1 to P6.

From the above, when the flatness is adjusted by adjusting the current holding pressure condition, it is difficult to maintain the same flatness for all points at the flatness measurement point. It is desired to mold the shell of the cartridge that secures the flatness higher than the flatness obtained by the mold device. Therefore, the present invention has been made to solve the above-mentioned problems, and a mold apparatus for injection molding and a shell of a cartridge capable of achieving highly accurate flatness of a shell of a cartridge having a thin and uneven thickness. It is an object of the present invention to provide an injection molding method of.

[0009]

According to the present invention, there is provided an injection molding die apparatus for injection molding a shell of a cartridge for accommodating a recording medium. A second mold forming a cavity for injecting a molding material to form a shell of the cartridge with the first mold, and a shell of the cartridge formed in the cavity. This is achieved by a mold device for injection molding, which comprises flatness adjusting means for adjusting the flatness of the shell of the cartridge by applying a compressive force to a predetermined position.

In the present invention, a cavity is formed between the first mold and the second mold for molding the shell of the cartridge. The flatness adjusting means applies a compressive force to a necessary portion of the shell of the cartridge formed in the cavity to adjust the flatness of the shell of the cartridge. As a result, the desired flatness can be obtained even though the shell of the cartridge has a product shape having a thin and uneven thickness.

The above object is, according to the present invention, an injection molding method for injection molding a shell of a cartridge for accommodating a recording medium, wherein the shell is formed between a first mold and a second mold. The molding material is injected to form the shell of the cartridge in the cavity, and the second mold is moved to the first mold side to compress and hold the shell of the cartridge in the cavity, and the shell of the cartridge. Is achieved by an injection molding method of the shell of the cartridge, in which the flatness of the shell of the cartridge is adjusted by partially applying a compressive force to a predetermined position of the shell of the cartridge during the holding pressure. According to the method of the present invention, a molding material is injected to mold a shell of a cartridge by a cavity between a first mold and a second mold and compressed against the shell of the cartridge in the cavity. The pressure is held, and the flatness of the cartridge shell is adjusted by applying a compressive force to a predetermined portion of the cartridge shell during the pressure holding. As a result, the desired flatness can be obtained even though the shell of the cartridge has a product shape having a thin and uneven thickness.

[0012]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limitations are given, the scope of the present invention is not limited to these modes unless otherwise specified to limit the present invention.

FIG. 1 is a sectional view showing a preferred embodiment of a mold apparatus for injection molding of the present invention. In FIG. 1, this mold device is used for molding the upper shell 1 shown in FIG. 9 or the lower shell 2 shown in FIG. 10 of a cartridge of an optical disk or a magneto-optical disk (mini disk MD) with high precision by injection molding. It is a mold device. This mold device includes a compression moving unit 10, a first mold 20, a second mold 30, and a flatness adjusting unit 40. The state of the mold apparatus of FIG. 1 shows the step of injecting the molten resin into the cavity C formed between the first mold 20 and the second mold 30, and For example, a state immediately before compression of the lower shell 2 obtained by injecting a molten resin.

A cavity C for forming the above-mentioned lower shell 2 is formed between a part 20a of the lower surface of the first mold 20 and an upper part 30a of the second mold 30. There is. For example, the cavity C that forms the appearance surface of the molded product is installed in the first mold 20, and the core CO that forms the back side of the molded product is installed in the second mold 30. The first mold 20 has a cavity block 20d, and the cavity C is provided in the cavity block 20d. The second mold 30 has an ejector plate 36 and an ejector pin 36a.

This second mold 30 is provided with flatness adjusting means 40. The compression moving means 10 has a hydraulic mechanism 11 and compression plates 12 and 13. The hydraulic mechanism 11 can push up the compression plates 12 and 13 in the direction of arrow X1 as a unit. Also, the hydraulic mechanism 11
Can also pull the compression plates 12, 13 back in the direction of arrow X2. The compression moving means 10 is included in auxiliary equipment such as a hydraulic mechanism of an injection molding machine. That is, the compression plates 12 and 13 are moved in the arrow X1 direction or the arrow X1 by the hydraulic mechanism 11 of the auxiliary mechanism such as the hydraulic mechanism of the injection molding machine.
2 can be moved. The compression advance stopper 14 is formed on the main body 79. The compression advance stopper 14 controls the compression plates 12 and 13 in order to regulate the total amount of compression of the lower shell 2 in the cavity C.
It is a stopper that stops the rise of. That is, the compression advance stopper 14 is provided to regulate the amount of compression of the entire lower shell 2 in the cavity C.

Next, the flatness adjusting means 40 will be described with reference to FIG.
Will be described with reference to FIG. The flatness adjusting means 40 is 3
It has book compression pins CP1, CP2, CP3. The compression pins CP1, CP2, CP3 are the lower shell 2 of FIG.
Of the flatness measurement points P1, P2, P3. The core block 50 of FIG.
Is provided in the second mold 30 of FIG.

FIG. 3 shows a portion E of the core block 50 of FIG.
3 is a partial sectional view of FIG. In FIG. 3, a bush 51 is fitted in the core block 50. The bush 51 is, for example, a bush for guiding the compression pin CP2, and a preset compression amount S is provided between the upper surface 52 of the core block 50 and the upper end surface 53 of the compression pin CP2. The space 54 corresponding to the set compression amount S becomes the compression amount to the lower shell 2 which is the molded product of FIG. The lower shell 2 which is the molded product of FIG.
The internal compression amount is set according to the wall thickness of the molded product at the installation location of each compression pin CP1, CP2, CP3. Since the overall amount of compression is set according to the place that requires the most compression, the space T between the compression plates 12 and 13 of FIG. 1 and the compression advance stopper 14 of FIG. Become.

Next, the R portion in FIG. 1 is shown enlarged in FIG. Referring to FIGS. 1 and 5, a compression dummy pin 70 is arranged axially corresponding to the compression pin CP3.
The compression dummy pin 70 is provided on the compression plate 12, and the compression pin CP3 is movable in the direction of arrow X1 or arrow X2 along the guide passage 31 of the second mold 30 in FIG. In addition, other compression pins CP1 and CP2
Is a single pin and is provided on the compression plate 12. As shown in FIG. 5, a columnar portion 81 is provided at the lower end portion of the compression pin CP3. This part 81 is
It is located in the cylindrical space 33 of the ejector plate 36 of the second mold 30. Moreover, the lower surface 82 of the portion 81 is
It is placed on the upper surface of another ejector plate 36 of the second mold 30. The compression dummy pin 70 is inserted in the guide hole 37a of the ejector plate 36 in the direction of arrow X1 or in the direction of arrow X1.
2 can be moved. Compression dummy pin 70
The upper end surface 71 of the is contacted with the lower surface 82 of the portion 81. A space LS for adjusting the compression amount is formed between the upper end surface 71 of the compression dummy pin 70 and the lower surface 82 of the portion 81. This space LS is provided when the compression plates 12 and 13 in FIG. 1 rise in the arrow X1 direction.
The compression dummy pin 70 also moves in the direction of the arrow X1 in synchronization, but in this case, the compression dummy pin 70 moves in the space LS.
The compression pin CP3 moves upward in the direction of arrow X1 after moving by a minute. Figure 1 with compression pin CP3
It is a movement loss space for adjusting the compression amount when the lower shell 2 is compressed. In addition, the spring 3 for forced return is provided in the guide hole 37a of the upper ejector plate 36.
7b is provided. Since the compression pin CP3 does not always return to the Y surface by the above compression amount after the compression process,
The spring 37b forcibly returns the compression pin CP3 to the Y surface after the compression process.

Next, the injection molding method using the injection molding die of the present invention will be described. FIG. 1 shows a state immediately before a compressive force is applied to the lower shell 2 obtained by injecting the molten resin into the cavity C and injecting it as described above. FIG. 4 shows the compression plates 12, 13
The upward movement process is shown, and the upper surface of the compression plate 13 is in contact with the compression advance stopper 14. 6 shows the final operation process of the lower shell 2 in the cavity C.

First, referring to FIG. 1, the second die 30 is raised in the direction of arrow X1 by the hydraulic mechanism 11 of the compression moving means 10 with respect to the first die 20. In this state,
The compression advance stopper 14 is not in contact with the compression plate 13 and has a space T that indicates the overall compression amount. Further, the upper end surface 71 of the compression dummy pin 70 in the portion R of FIGS. 1 and 5 is the portion 8 of the compression pin CP3 as shown in FIG.
A space LS is formed in the lower surface 82 of No. 1. Therefore, the compression dummy pin 70 which is the second compression member is separate from the compression pin CP3 which is the first compression member.

Molten resin such as polycarbonate is injected into the cavity C between the first mold 20 and the second mold 30. Therefore, the lower shell 2 is located in the cavity C as a molded product. And the first mold 2 in FIG.
By maintaining the positional relationship between 0 and the second mold 30,
The pressure holding step is performed after the completion of the molten resin injection step. In this pressure-holding step, the compression plates 12 and 13 move upward in the arrow X1 direction by the operation of the hydraulic mechanism 11 as shown in FIG. In this state, the compression pins CP1 and CP2 rise and apply a compressive force to the flatness measurement points P1 and P2 of the lower shell 2. On the other hand, the compression dummy pin 70 of FIG. 5 rises together with the compression plates 12 and 13 in the arrow X1 direction, and the upper end surface 71 of the compression dummy pin 70 has a portion 81 of the compression pin CP3.
The lower surface 82 of the. Therefore, the compression pin CP3 of FIG.
Starts to move in the direction of the arrow X1 in FIG. 1 and starts to move to the upper end surface side of the compression pin CP3 in FIG. As described above, since the compression amount is set by the wall thickness of the molded product, the overall compression amount is regulated by the compression advance stopper 14 shown in FIG. A quantity adjustment mechanism is required. That is, the compression amount adjusting mechanism 99 of FIG. 5 has a space L for adjusting the compression amount.
The portion of S adjusts (delays) the time when the compression pin CP3 starts moving in the direction of the arrow X1, and the compression pin CP3
3 can adjust the compression amount for the flatness measurement point P3 in FIG.

Such compression pins CP1, CP2, CP
3 is a molded product, the measurement point P of the lower shell of FIG.
By being respectively pressed against 1, P2 and P3, the respective points P1 to P3 can be compressed by appropriate compression amounts. Therefore, the accuracy of the flatness of the lower shell 2 which is a molded product can be improved. FIG. 7 shows a state in which the upper end surface 53 of the compression pin CP3 is compressed with respect to the lower shell 2 which is this molded product. FIG. 7 shows a portion A of FIG. As shown in FIG. 6, since the compression plate 13 has already abutted against the compression advance stopper 14, the compression process into the lower shell 2 is completed.

As described above, the flatness adjusting means 40 is provided in the mold, and the compression operation is performed into the lower shell 2 during the pressure-holding process for the lower shell 2, which is a molded product.
The flatness of the lower shell 2 can be adjusted by locally applying a compressive force to the points P1 to P3.

The present invention is not limited to the above embodiment. Although the lower shell 2 is taken as an example of the molded product in the above-described embodiment, the present invention is not limited to this, and the same can be applied when manufacturing the upper shell of FIG. In this case, the core block 150 shown in FIG. 8 is used. The core block 150 has flatness measurement points P4, P shown in FIG.
5, compression pins CP4, CP5, CP6 corresponding to P5 and P6 are provided. Since the other points are almost the same as those of the embodiment shown in FIGS. 1 to 7, description thereof will be omitted.

Further, in the above-described embodiment, an example of forming the shell of the cartridge of the optical disk or the magneto-optical disk is described, but the present invention is not limited to this, and other types of cartridges such as a cartridge of 3.5 inch floppy disk, etc. It can of course be used for injection molding shells of cartridges in other fields.

[0026]

As described above, according to the present invention,
The flatness of the shell of a cartridge having a thin and uneven thickness can be made highly accurate.

[Brief description of drawings]

FIG. 1 shows a mold apparatus for injection molding of the present invention,
The figure which shows the state before compressive force is applied to a molded product.

FIG. 2 is a diagram showing a core block of the mold device of FIG.

3 is a cross-sectional view showing a portion E of the core block of FIG.

FIG. 4 is a diagram showing a state in which a compression plate is raised and abuts against a compression advance stopper.

5 is an enlarged sectional view showing a portion R of FIGS. 1 and 4. FIG.

FIG. 6 is a view showing a state in which a molded product is compressed by a compression pin of the flatness adjusting means.

7 is an enlarged cross-sectional view showing a portion A of FIG.

FIG. 8 is a diagram showing an example of a core block different from the core block of FIG.

FIG. 9 is a view showing an upper shell of a cartridge of a normal magneto-optical disk.

FIG. 10 is a diagram showing a lower shell of a cartridge of a normal magneto-optical disk.

FIG. 11 is a view showing an example of a sled state of the upper shell and the lower shell.

[Explanation of symbols]

 1 Upper Shell 2 Lower Shell 10 Compression Moving Means 20 First Mold 30 Second Mold 40 Flatness Adjusting Means 70 Compression Dummy Pins (Second Compression Member) CP3 Compression Pins (First Compression Member)

Claims (6)

[Claims] 1. A mold apparatus for injection molding for injection molding a shell of a cartridge for accommodating a recording medium, comprising: a first mold; and a shell of the cartridge between the first mold and the mold. A second mold forming a cavity for injecting a molding material to form a mold, and a flatness of the shell of the cartridge by applying a compressive force to a predetermined position of the shell of the cartridge formed in the cavity. And a flatness adjusting means for adjusting. 2. The mold apparatus for injection molding according to claim 1, wherein the second mold is provided with compression moving means for forming a cavity by moving with respect to the first mold. . 3. The flatness adjusting means is integrated with the first compression member that moves in synchronization with the operation of the compression moving means, and the first compression member when the first compression member moves a predetermined distance. The mold device for injection molding according to claim 2, further comprising: a second compression member that starts moving and applies a compression force to a predetermined position of the shell of the cartridge. 4. The mold apparatus for injection molding according to claim 1, wherein the recording medium is a magneto-optical disk, and the shell of the cartridge is an upper shell or a lower shell. 5. An injection molding method for injection molding a shell of a cartridge for containing a recording medium, the shell of the cartridge being formed in a cavity formed between a first mold and a second mold. To inject the molding material, the second mold and the first mold compress the shell of the cartridge in the cavity to hold the pressure, and the shell of the cartridge is held at a predetermined position on the shell of the cartridge during the pressure holding. An injection molding method for a shell of a cartridge, characterized in that a flatness of the shell of the cartridge is adjusted by partially applying a compressive force. 6. The injection molding method for a shell of a cartridge according to claim 5, wherein the recording medium is a magneto-optical disk, and the shell of the cartridge is an upper shell or a lower shell.