JP2003080537A - Mold for molding plastics and molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for molding plastics capable of inexpensively manufacturing a plastic product and capable of easily detaching the molded plastic product, and a molding method using the mold. SOLUTION: In the mold for injecting molten plastics to mold the same into a predetermined shape, a non-adhesive plastic sheet is held between a pair of molds to be thermoformed. A sheetlike mold of which the inner surface is formed into a prescribed shape and a sheet fixing fixture for supporting the outer surface of the sheetlike mold to fix the same and preventing the deformation of the sheetlike mold are provided and the molten plastics is injected in the cavity formed by the inner surface of the sheetlike mold to be molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molding die capable of easily removing a molded plastic product from a molding die in a plastic molding operation for injecting a molten plastic into a predetermined shape. The present invention relates to a molding method using this molding die, and in particular, in order to protect an optical electronic component fixed to the surface of a printed circuit board, a plastic molded article made of an optical plastic covering the optical electronic component is provided. Printed circuit board It is molded and fixed on the surface of the board, and the molded optodevice can be easily removed from the mold in the plastic molding work to form a small optodevice by this optical component and the plastic molding. The present invention relates to a plastic molding die and a molding method using this molding die. It is intended.

[0002]

2. Description of the Related Art Optical electronic components, particularly small optodevices using light emitting elements such as LEDs and lasers, cover and protect light emitting elements such as LEDs and lasers fixed to the surface of a printed circuit board. LED of optical plastics such as acrylic resin and epoxy resin
It is known that a compact opto-device in which an LED, a laser, and the like and an optical plastic are integrated is formed by molding by covering with a laser or the like. The plastic molded body molded at this time is formed in a predetermined shape in order to converge the light projected from the light emitting element such as an LED or a laser in a certain direction from the simplest one that is simply potted. Various molding methods have been used to accurately mold a molding die into a predetermined shape.

Particularly, in a case where a plastic for optical use which is covered with a light emitting element such as an LED or a laser to be protected is formed in a predetermined shape by a molding die, a mold release agent is formed on the inner surface of the die as shown in FIG. It is known to be applied and used. This molding die 30 is used by applying a release agent to the inner surface of a mold 31 processed into a predetermined shape, and the release agent is usually applied by a spray 32 as shown in the figure. Release agent 33
The method of spraying and spraying is adopted. However, it is very difficult to uniformly apply the release agent 33 to the inner surface of the mold, and uneven coating may easily occur, or the coated surface may not be perfectly smooth, resulting in uneven coating. When it occurs, the precision of the opto device that is the product becomes insufficient, and when the surface is not completely smooth,
As a result, a part of the surface of the opt device is deformed, which has been a cause of defective products. In addition, since the release agent adheres to the surface of the opto-device of the product, it is necessary to perform a washing process to wash off the release agent after removing the opto-device from the molding die. It has been an obstacle to reducing the cost of the circuit board.

Further, as shown in FIG. 5, it is also known to use a mold 35 in which the inner surface of the mold is coated with a film of non-adhesive plastic such as Teflon (registered trademark). In this case, the mold 36 is formed by forming the coating layer 37 of non-adhesive plastic such as Teflon (registered trademark) on the inner surface of the mold 36 to form the mold 35, and the performance as the mold can be almost satisfied. Although it is a thing
Since the inner surface of a precisely processed mold must be coated with a uniform thickness, the molding die becomes expensive, and because the durability of the coating is low, the coating often has to be redone, and as a molding die, Increasing the manufacturing cost is unavoidable, and as a result, it has been an obstacle to reducing the cost of the printed circuit board on which the optical device is arranged.

Further, as shown in FIG. 6, it is also known to use a molding die 40 whose entire molding die is made of a non-adhesive plastic such as polyacetal. In this case, the molding die 40 is made of a non-adhesive plastic having relatively high rigidity and high heat resistance such as polyacetal, and the molding die 40 is used to mold the opto-device. Although it has the advantage that it is easy to manufacture, since a mold is manufactured with plastic, a mold for manufacturing the mold is required. Since the entire molding die is manufactured, it has a drawback that it is insufficient in rigidity and easily deformed, and thermal deformation is large, so that it is not suitable for molding an opto-device that requires high accuracy.

In the case of mass-producing printed circuit boards on which opto-devices are formed, it goes without saying that a large number of these molds must be prepared. With a mold made entirely of non-adhesive plastic, a large number of molds can be manufactured at a relatively low cost by repeatedly using the mold for manufacturing the mold. For molds that have a release agent applied to the inner surface and molds that have a non-adhesive plastic coating coated on the inner surface of the mold, the accuracy of the mold is the same as that of the optical device that is the product. Since it is transferred, it is necessary to individually manufacture a large number of molds that require high accuracy, are difficult to process, and are expensive, which increases the manufacturing cost of the mold, and as a result, the printed circuit on which the opto-device is arranged. It was difficult to reduce the cost of the board.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above problems of the prior art, and in a molding operation of a plastic in which molten plastic is injected and molded into a predetermined shape, a molded plastic product is formed. The present invention provides a plastic molding die that can be easily removed from the molding die and can be manufactured at low cost, and a molding method using this molding die, and in particular, it is fixed on the surface of a printed circuit board. In order to protect the optical / electronic component, a plastic molded body made of optical plastic covering the optical / electronic component is molded and fixed on the surface of the printed circuit board substrate, and the optical component and the plastic molded body make it possible to reduce the size of the optical circuit. In the molding work of the plastics that form the opto-device, the precision of the molded opto-device The present invention provides a plastic mold and a molding method using the mold, which are high in cost, can be easily removed from the mold, and require no post-process such as cleaning, and can be manufactured at low cost. is there.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention provides a pair of metal molds in a plastic molding die for injecting molten plastic into a predetermined shape. A sheet of non-adhesive plastic is sandwiched between molds and thermoformed, and a sheet-shaped forming die having an inner surface formed in a predetermined shape and an outer surface of the sheet-shaped forming die are supported and fixed, and the sheet-shaped forming is performed. A plastic molding die, comprising: a sheet fixing jig for preventing deformation of the die; and pouring the molten plastic into a cavity formed by an inner surface of the sheet-shaped molding die to mold the sheet. To do.

Here, the plastic mold is the sheet-shaped mold supported by the sheet fixing jig,
It is desirable that the sheet-shaped molding die be composed of a flat plate-shaped base material that is disposed so as to face the inner surface side. The plastic mold is a printed circuit board on which the flat base material fixes electronic components on the surface, and the molten plastic is injected into the cavity formed by the sheet mold. It is desirable to form a plastic molded body that is integrally fixed to the printed circuit board and protects the components fixed to the surface of the printed circuit board, and further, the molten plastic is an optical plastic. It is desirable to form an opto-device by the optoelectronic components fixed on the surface of the printed circuit board and the plastic molding.

In order to solve the above-mentioned problems of the prior art, the present invention sandwiches a sheet of non-adhesive plastic with a pair of molds and thermoforms it to form the inner surface into a predetermined shape. A sheet-shaped forming die, and a sheet-fixing jig for supporting and fixing the outer surface of the sheet-shaped forming die and preventing deformation of the sheet-shaped forming die; and a forming die facing the forming die. Having a flat plate-shaped base material disposed therein, and injecting molten plastic into a cavity formed between the molding die and the flat plate-shaped base material, to the surface of the flat plate-shaped base material. The present invention provides a plastic molding method, which comprises forming a plastic molded body.

Here, the plastic molded body is an optical plastic for protecting an optical electronic component fixed to the surface of the printed circuit board, and an opto-device is formed by the optical electronic component and the plastic molded body. Is desirable.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to the drawings illustrating an embodiment. FIG. 1 is a cross-sectional view showing one embodiment of a mold for an opto-device of the present invention,
FIG. 2 is an explanatory view showing a method for manufacturing a sheet-shaped mold, and FIG. 3 is a sectional view of the sheet-shaped mold.

As shown in FIG. 1, a molding die 1 for an optical device of the present invention comprises a sheet-shaped molding die 2 and an outer surface of the sheet-shaped molding die 2 supported and fixed from the outside and a sheet-shaped molding die. 2 is disposed between the plastic molding die including a sheet fixing jig 3 for preventing deformation of the plastic molding die 2 and the inner surface 2a side of the sheet molding die 2 of the plastic molding die. And a flat plate-shaped base material 5 forming a cavity 4 for injecting the melted plastic into the surface. In this embodiment, the flat plate-shaped base material 5 has a plurality of LED elements 6 which are optical electronic parts on the surface thereof. The sheet-shaped mold 2 is a printed circuit board 7 fixed to a cavity for injecting molten optical plastic, for example, acrylic resin or epoxy resin, corresponding to the plurality of LED elements 6. There are formed in the same position by the same number.

Here, the sheet-shaped molding die 2 will be described later in detail, but a sheet of non-adhesive plastic having relatively high rigidity and high heat resistance, such as polyacetal, is thermoformed, and its inner surface 2a is optically formed. A plastic for molding is formed into a predetermined shape, and the outer surface of the sheet-shaped mold 2 is supported and fixed by a sheet fixing jig 3 from the outside, and is deformed when the optical plastic is cured. To prevent that. Therefore, the inner surface 2a of the sheet-shaped molding die 2 needs to be molded into a mirror surface with high precision necessary for molding a plastic molded body formed by curing the optical plastic in the cavity 4. 2b
Since it is only supported and fixed by the sheet fixing jig 4 so as not to be deformed, it does not require particularly high accuracy, nor does it require surface roughness or a mirror surface.

As described above, the plastic molding die of this embodiment is arranged so as to face the sheet-shaped molding die 2 and the sheet-shaped molding die 2 whose outer surface is supported and fixed by the sheet fixing jig 3. The flat plate-shaped base material 5 is used as it is as the one mold. When the plate-shaped substrate 5 is the printed circuit board 7 to which the optical electronic components such as the LED element 6 are fixed, the injection pressure at the time of injecting the optical plastic and the deforming force at the time of curing the injected plastic. As a result, it is conceivable that the printed circuit board 7 is insufficiently rigid and bent, and the shape of the plastic molded product changes, so that it is impossible to guarantee a predetermined accuracy. In such a case, the flat substrate 5
By disposing the backup plate 8 on the back surface of the (printed circuit board 7), it is possible to prevent the flat substrate 5 (printed circuit board 7) from being deformed.

Of course, the plastic mold of the present invention is
The present invention is not limited to the configuration in which the sheet-shaped molding die 2 is combined with the flat-plate-shaped substrate 5 and the sheet-fixing jig 3 described in the above examples, and the sheet-shaped molding fixed to the sheet-fixing jig 3 is not limited thereto. Using two sets of molds consisting of mold 2,
It is also possible to arrange them so as to face each other. Then, in this case, a cavity having an arbitrary three-dimensional shape can be formed similarly to a normal mold, and a three-dimensional plastic molded product having an arbitrary shape can be obtained.

Next, a method of manufacturing the sheet-shaped mold 2 will be described. As shown in FIG. 2, the sheet-shaped forming die 2 is sandwiched between an upper die 10 and a lower die 11 and thermoformed, and is formed on the upper die 10 or the lower die 11 or both of them. A heat source is provided, and a molded sheet 1 made of non-adhesive plastic such as polyacetal is provided between the upper mold 10 and the lower mold 11.
Thermoforming is performed by sandwiching 2 and pressing. At this time, since the convex surface 10a of the upper mold 10 is transferred to the inner surface 3a of the sheet-shaped molding die 3, the convex surface 10a has a predetermined shape and must be processed with high accuracy so that the surface is also a mirror surface. Since the concave surface 11a of the lower mold 11 forms the outer surface 2b of the sheet-shaped molding die 2 and comes into contact with the sheet fixing jig 3, it is not necessary to perform processing with high accuracy and the surface roughness is good until now. Is clear.

Here, as the non-adhesive plastic forming the sheet-shaped mold 2, in addition to polyacetal, T
PX, Teflon, cellulose or the like can be used, and it is preferable that the molded plastic molded body has a certain degree of rigidity so that it can be easily peeled off at the time of releasing from the mold.

FIG. 3 shows the shape of the sheet-shaped molding die 2 molded in this way. In the figure, the thickness of the sheet-shaped mold 2 is drawn to be constant, but the sheet-shaped sheet 1 to be molded 1
Needless to say, the thickness of each part may be different within a range that does not interfere with thermoforming with the two sandwiched. When the thickness of each part of the sheet-shaped molding die 2 is different,
The shape of the concave surface of the sheet fixing jig 3 shown in FIG. 2 must match the shape of the outer surface 2b of the molded sheet-shaped molding die 2, but depending on the thickness of the sheet-shaped molding die 2, the sheet-shaped molding die 2 itself. Since it also has a certain degree of rigidity, it is not necessary to process it with high precision and it is not necessary to polish the surface to a mirror surface.

Further, the lower mold 11 used in the molding process of the sheet-shaped mold 2 is used as it is for the sheet fixing jig 3
It is also possible to use as. In this case, it is preferable that the concave surface 11a of the lower mold 11 is made rough so that the sheet-shaped molding die 2 and the sheet fixing jig 3 are firmly fixed to each other. As described above, since the lower mold 11 does not need to be processed with high precision, it can be manufactured at the same low cost as the sheet fixing jig 3 and is firmly fixed in close contact with the sheet-shaped molding die 2. Therefore, in terms of supporting and fixing the outer surface of the sheet-shaped mold 2 from the outside and preventing deformation, a better result is obtained as compared with the case where the sheet-fixing jig 3 is manufactured separately and the sheet-shaped mold 2 is assembled. Obtainable.

Alternatively, it is desirable that the outer surface 2b of the sheet-shaped molding die 2 be bonded and fixed to the sheet fixing jig 3. By adhering and fixing the sheet-shaped molding die 2 to the sheet fixing jig 3, the plastic molded article and the sheet-shaped molding die 2 adhere to each other when the plastic molded article is cured and then taken out from the molding die. The sheet-shaped molding die 2 is prevented from peeling off from the fixing jig 3. If this adhesion is reliable, the rigidity of the sheet-shaped mold 2 is almost unnecessary. Then, by repeatedly molding the plastic, wear or the like occurs, and the sheet-shaped molding die 2
If an error occurs in the shape of the inner surface 2a of the sheet-shaped molding die 2, the shape of the inner surface 2a of the sheet-shaped molding die 2 is changed by sandwiching it between the upper die 10 and the lower die 11 and pressing them while heating. Can be played.

The plastic molding die thus constructed is attached to a plastic molding device (not shown) and melted in a cavity formed between the flat plate-shaped base material 5 and the sheet-shaped molding die 2. The molded plastic is injected and the plastic molded body is integrally fixed to the flat plate-shaped substrate 5 for molding. As in the embodiment shown in FIG. 1, when the flat plate-shaped substrate 5 is the printed circuit board 7 having the surface on which the optical electronic components such as the LED element 6 are fixed, the molten optical plastic is injected. The plastic molded body protects the electronic components fixed to the surface of the printed circuit board 7 and also forms an optical device together with the optical electronic components such as the LED element 6 and the like.

The plastic molding die and molding method of the present invention have been described above. However, as described above, the present invention uses two sets of molding dies each including a sheet-shaped molding die fixed to the sheet fixing jig. The present invention is not limited to the embodiments described in the examples, and can be arranged and arranged to face each other, and various changes and improvements can be made without departing from the scope of the present invention. Of course, you can do that.

[0024]

Since the plastic molding die and molding method of the present invention are constructed as described above, it is necessary to process the plastic mold and the surface so as to have a predetermined high precision and a mirror surface. The lower mold 1 has only the convex surface 10a of 10
The sheet fixing jig 1 and the sheet fixing jig 3 do not need to be processed with high accuracy and the surface does not need to be polished to a mirror surface. Further, since the upper mold 10 which is expensive as in the conventional technique can be repeatedly used as a mold for manufacturing the sheet-shaped molding die 2, mass production of a plastic molding (opto device) is performed. In this case, a large number of molding dies can be manufactured at low cost with one upper mold 10. Then, the inner surface 2a of the sheet-shaped molding die 2 that requires precision in order to come into contact with the melted plastic transfers the precision of the convex surface 10a of the upper die 10 by thermoforming, so that it can be manufactured at low cost. In addition to being capable of being repeatedly reproduced, it is possible to obtain an inexpensive plastic molding die as a whole.

The sheet-shaped molding die 2 has sufficient rigidity by being supported and fixed by the sheet fixing jig 3 from the outside, and is deformed by the injection pressure at the time of molding or when the plastic is cured. It is possible to prevent deformation and obtain a plastic molded body with sufficiently high accuracy and quality. Furthermore, since a mold release agent is not used, cleaning after molding is unnecessary, and since there is no coating of Teflon or the like, maintenance such as recoating is also unnecessary, which is a great effect.

Furthermore, since the sheet-shaped molding die 2 is made of non-adhesive plastic, in the molding operation of the plastic for injecting the molten plastic into a predetermined shape, the molded plastic product is molded. Can be easily removed from.

In particular, in order to protect the optical and electronic parts fixed to the surface of the printed circuit board, a plastic molding made of optical plastic covering the optical and electronic parts is formed on the surface of the printed circuit board. In the plastic molding work of fixing and forming a small-sized opto-device by the optical component and the plastic molding, the molded opto-device which is a product has high accuracy and can be easily removed from the molding die. It is possible to provide a plastic molding die that does not require a post-process such as cleaning and can be manufactured at low cost, and a molding method using this molding die.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a mold for an opto-device of the present invention.

FIG. 2 is an explanatory view showing a method for manufacturing a sheet-shaped mold.

FIG. 3 is a cross-sectional view of a sheet-shaped forming die.

FIG. 4 shows a conventional technique of a mold for an opto-device, and is an explanatory diagram of a mold used by applying a release agent to the inner surface of the mold.

FIG. 5 is a cross-sectional view of a molding die in which a non-adhesive plastic is coated on the inner surface of a mold, showing a conventional technique of a molding die for an optical device.

FIG. 6 is a cross-sectional view showing a conventional mold for an opto-device, which is entirely made of non-adhesive plastic.

[Explanation of symbols]

1 Mold 2 sheet mold 2a inner surface 2b exterior 3 Sheet fixing jig 4 cavities 5 Flat substrate 6 LED element 7 printed circuit board 8 backup plate 10 Upper mold 10a convex 11 Lower mold 11a concave 12 Molded sheet

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29L 31:34 B29L 31:34 F term (reference) 4F202 AA39 AA43 AD18 AH37 AJ03 AJ09 CA01 CB01 CB12 CB17 CD01 CD30 4F204 AA39 AA43 AD18 AH36 AH37 AH73 AJ03 AJ09 EA03 EA04 EA06 EA07 EB01 EB12 EF27 EK24 EK25 4F206 AD18 AH36 AH37 AJ02 AJ09 JA07 JB12 JB17 JA17 DA06 BA21 DA21 DA06 DA21 DA06 DA21 DA04

Claims (6)

[Claims] 1. A plastic molding die for injecting molten plastic into a predetermined shape to sandwich a sheet of non-adhesive plastic between a pair of molds and thermoforming it so that the inner surface has a predetermined shape. The formed sheet-shaped mold and the outer surface of the sheet-shaped mold are supported and fixed, and
A sheet fixing jig for preventing deformation of the sheet-shaped forming die, wherein the molten plastic is injected into a cavity formed by an inner surface of the sheet-shaped forming die to form the plastic. Mold. 2. The plastic molding die comprises: the sheet-shaped molding die supported by the sheet fixing jig; and a flat-plate-shaped base material which is arranged to face the inner surface side of the sheet-shaped molding die. The plastic molding die according to claim 1, wherein: 3. The printed circuit board, wherein the plate-shaped base material fixes an electronic component on a surface thereof, and the molten plastic is injected into the cavity formed by the sheet-shaped molding die. 3. The plastic molding die according to claim 2, wherein the plastic molding body is integrally fixed to the surface of the printed circuit board to protect a component fixed to the surface of the printed circuit board. 4. The optical plastic is used as the molten plastic, and an opto-device is formed by an optical electronic component fixed to the surface of the printed circuit board and a plastic molded body. Mold of the described plastic. 5. A sheet-shaped forming die having an inner surface formed in a predetermined shape, and a sheet-shaped forming die supporting the outer surface of the sheet-shaped forming die by sandwiching and thermoforming a sheet of non-adhesive plastic with a pair of dies. A mold having a sheet fixing jig for fixing the sheet mold and preventing deformation of the sheet mold, and a flat plate-shaped base material arranged to face the mold, A method for molding plastic, characterized in that molten plastic is injected into a cavity formed between the flat base material and a plastic molded body on the surface of the flat base material. 6. The plastic molding is an optical plastic for protecting an optoelectronic component fixed to the surface of a printed circuit board, and an opto-device is formed by the optoelectronic component and the plastic compact. The method for molding plastic according to claim 5, wherein