JP2013151097A - Mold for partial compression molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely manufacture a partially thin resin molded article having a plurality of thin parts without excessively enlarging an apparatus or a steep rise in costs.SOLUTION: In a mold 1 for partial compression molding for forming a plurality of thin parts in a resin molded body 50 by sliding a plurality of slide cores 35a, 35b provided to a core-side mold block 3 in a direction perpendicular to mold opening and closing directions and toward a core 31 side surface after injecting and filling a molten resin, a cavity-side mold block 2 is provided with a plurality of compression bars 25a, 25b extended therefrom and a compression plate 22 capable of operating in the mold opening and closing directions. Each of the compression bars 25a, 25b is arranged so that a slope 253 is formed at a distal end side thereof and is in close contact with a slope 353 formed on each of the slide cores 35a, 35b. By pushing in the compression plate 22 in a mold closing direction, each of the slopes 253, 353 are shifted from each other so that each of the slide cores 35a, 35b is slid in a compression direction.

Description

  The present invention relates to a partial compression molding die, and more particularly to a molding die for producing a resin molded product having a plurality of thin portions.

  When forming an extremely thin part (for example, less than 0.7 mm thick) in a resin molded product, filling the molten resin into the thin part in the mold molding space tends to be insufficient, so high-precision and high-quality resin molding There is a problem that it is difficult to obtain goods. Therefore, it is conceivable to inject and mold at a higher pressure than usual so that the molten resin can be sufficiently distributed to all parts in the mold molding space. Higher strength is required, which tends to be a problem in terms of cost.

  On the other hand, as described in Japanese Patent Application Laid-Open No. 10-34718, after the molten resin is injected / filled into the mold forming space, the portion constituting the thin portion before the resin is solidified is a slide core ( There is known a partial compression molding method in which the thickness is reduced by compression with a sliding piece. By using this technology, it is possible to control the compression force while converting the drive force from a servo motor or the like separate from the resin injection drive source into the linear motion of the slide core. It can be partially formed.

  However, when the conventional partial compression molding method including the technique described in the above-mentioned publication is applied to the manufacture of a resin molded product having a plurality of thin portions at distant positions, a plurality of locations with one compression drive source The system that compresses the two at the same time requires a high-strength and complex link mechanism, which tends to increase the size and cost of the device, and it is not easy to control the thickness of all thin parts with high accuracy. Absent. On the other hand, the method of operating each slide core with an individual drive source requires an installation space for each drive source and requires precise control thereof, which tends to further increase the size and cost of the apparatus.

  Furthermore, in the case where a plurality of thin portions are provided in the circumferential direction in a cylindrical resin molded product, in cases where the compression directions are different, it is necessary to provide a movable means and a drive source for each slide core. Furthermore, in common with each of the above-described technologies, it is usually necessary to provide a mechanism for pulling back each slide core to a pre-compression position at the time of demolding after molding, which adds space and cost. Will be.

Japanese Patent Laid-Open No. 10-34718

  The present invention is intended to solve the above-mentioned problems, and a partially thin resin molded product having a plurality of thin portions can be obtained with high accuracy without incurring an excessive increase in the size of the device or an increase in cost. An object is to enable manufacture.

  Therefore, the present invention comprises a core-side mold block and a cavity-side mold block. After both mold blocks are closed with a predetermined injection molding machine, the molten resin is injected and filled into the molding space. The resin molded body before solidification is partially compressed by sliding a plurality of slide cores arranged in the mold block in a direction perpendicular to the mold opening and closing direction and toward the side of the core with a predetermined movable means. In the partial compression molding mold that forms multiple thin parts, the other mold block has a plurality of compression bars extending from the tip surface in the mold closing direction and is opened and closed by external drive means. A compression plate operable in a direction is disposed inside, and each compression bar has a chamfered inclined surface formed so as to face the oblique tip direction on the tip side, and each slide core or each slide core base end Side contact Are arranged so as to be in close contact with the inclined surfaces formed at predetermined positions of the id member, and when the compression plate is pushed in the mold closing direction by the driving means, the both inclined surfaces are displaced from each other, and the slide cores are compressed. It was made to slide on.

  In this way, a compression plate having a plurality of compression bars is arranged inside one mold block, and the slide core is compressed by the inclined surface on the tip side of the compression bar by pushing the compression plate from the outside. By adopting a structure that operates in the direction, it is possible to form a plurality of thin parts at the same time while realizing a large compressive force in each slide core by only one pushing operation of one compression plate. A plurality of thin portions can be formed with high accuracy with a relatively simple configuration without incurring costs.

  Further, in this case, the resin molded body to be manufactured has an annular peripheral wall formed along the outer peripheral surface of the core, and each compression bar slides each slide core in the center direction of the resin molded body. If it is arranged on the compression plate in the direction of the position / inclined surface, when multiple thin-walled parts with different orientations are provided at different positions in the circumferential direction in the cylindrical resin molded product Even so, the molding can be performed only by pushing one of the compression plates without requiring a plurality of driving sources.

  Further, in the partial compression molding die described above, the tip portion having the inclined surface of the compression bar is formed into a plate shape whose width in the compression direction is 1.5 times or more larger than the width in the direction perpendicular thereto. If it is characterized in that the sliding contact part of the inclined surface is constituted by the side surface tip part on the compression direction side, a compact part to enable the number of slide cores to be accommodated according to the number of slide cores Even when is used, the strength becomes high in the compression direction, and a high compressive force is easily exhibited.

  In this case, the compression bar is configured to perform a compression operation in a state where at least a half of the base end side of the side opposite to the compression direction side is in sliding contact with the inner surface of the mold block. Assuming that the side surface in the deformation direction of the compression bar accompanying the compression operation is supported by the inner surface of the mold block, the strength is further improved.

  Furthermore, in the partial compression molding die described above, the other die block is formed by stacking a plurality of plates, and the most proximal plate has a proximal end surface on the injection molding machine side. A plurality of guide bars and a plurality of release bars are extended from the front end surface, and the other plates can be opened and closed within a predetermined range with the guide bars and the release bars inserted. Is formed in an undercut shape on the distal end side of the release bar that is linked to this, while the most proximal plate opens first in the mold opening operation after molding. The inclined surfaces are displaced from each other while being in close contact with the inclined surface formed at a predetermined position of the slide core, so that the slide core is pressed in the backward direction and returned to the position before compression. If the stop part is engaged and the other plate is opened to enter the mold open state, each slide core subjected to the partial compression operation has a dedicated drive means and complicated movable means. Without being provided, the mold can be removed while performing the backward movement in conjunction with the mold opening operation.

  In addition, in the partial compression mold described above, the compression plate is pushed and pulled back by the drive bar inserted and connected from the injection molding machine side protruding and retracting by the driving force of the electric motor. If it is characterized in that it is performed, it is possible to accurately control the compression force in accordance with the amount of pressing of the compression bar, and the thickness of the thin portion can be controlled with high accuracy.

  According to the present invention, a compression plate having a plurality of compression bars is provided in one mold block, and a plurality of slide cores that operate in the compression direction by pressing the compression bar are provided in the other mold block. Thus, it is possible to manufacture a resin molded product with high accuracy without causing an excessive increase in the size of the apparatus or an excessive increase in cost.

It is a perspective view of the metal mold | die for partial compression molding which is embodiment in this invention. FIG. 2 is a view for explaining the principle of operation of a slide core in a partial compression molding die formed by combining both mold blocks of FIG. 1, wherein (A) is an exploded perspective view, and (B) is an assembled perspective view. FIG. It is a longitudinal cross-sectional view which shows the state at the time of the mold closing of the metal mold | die for partial compression molding which combines both the mold blocks of FIG. It is the fragmentary longitudinal cross-section which expanded the part enclosed with the dashed-two dotted line of FIG. It is a fragmentary longitudinal cross-section which shows the state which performed the compression operation from the state of FIG. It is the fragmentary longitudinal cross-sectional view which expanded the part enclosed with the dashed-two dotted line of FIG. It is a fragmentary longitudinal cross-section which shows the state which canceled compression from the state of FIG. It is a fragmentary longitudinal cross-section which shows the state of mold release preparation which made the slide core retreat from the state of FIG. It is the fragmentary longitudinal cross-sectional view which expanded the part enclosed with the dashed-two dotted line of FIG. FIG. 10 is a partial longitudinal sectional view showing a state where the mold is opened from the state of FIG. 9 until the core comes out of the cavity. It is a fragmentary longitudinal cross-section which shows the state which opened the type | mold completely from the state of FIG. It is a fragmentary longitudinal cross-section which shows the state lifted to the position which can take out the resin molded product from the state of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In this embodiment as well, the pressure sensor of the compression section and its wiring, temperature control pipe, etc., which are frequently used in the conventional partial compression mold, are provided at necessary places, but illustration and description thereof are omitted. Shall.

  FIG. 1 shows a cavity-side mold block 2 and a core-side mold block 3, and these two mold blocks are combined into one at their mating surfaces 20, 30, so that partial compression according to this embodiment is performed. The molding die 1 is obtained. This partial compression molding die 1 is for producing a resin molded product having a plurality of thin portions (for example, a thickness of 0.7 to 0.3 mm), in particular, an annular peripheral wall. In the production of the resin part having, it is suitable for forming a plurality of thin portions having different directions at different positions in the circumferential direction by a partial compression molding method.

  This embodiment comprises a combination of a cavity side mold block 2 and a core side mold block 3, and these base end sides are attached to a commercially available electric injection molding machine, the mold is closed, and molten resin is injected into the forming space. After the filling, a plurality of slide cores 35a and 35b disposed so as to be slidable only in the radial and centripetal direction around the core 31 of the core-side mold block 3 are moved in the mold opening / closing direction by a movable means described later. By sliding in the direction perpendicular to the side surface of the core 31, the resin molded body before solidification is partially compressed to form a plurality of thin portions.

  In the present invention, as shown in FIG. 1, the cavity-side mold block 2 is provided with an ejector plate (for compression) in which compression bars 25a and 25b extend from the front end surface (upper surface in the figure) in the mold closing direction. (Plate) 22 is disposed inside, and the distal end side of a plurality of drive bars 114,... (See FIG. 3) inserted from the mounting surface of an electric injection molding machine (not shown) on the base end side thereof. It is connected and can be operated in the mold opening and closing direction by motor drive.

  Further, the compression bars 25a and 25b extending from the ejector plate 22 protrude from the mating surface 20 at the front end sides thereof, and constitute the movable means of the slide cores 35a and 35b. The feature is that all the slide cores 35a and 35b are slid in the compression direction only by operating in the mold closing direction.

  That is, as shown in FIGS. 2A and 2B, an inclined surface 253 formed in a chamfered manner so as to face a slightly oblique front end side of the one side surface of the compression bar 25a is formed on the slide core 35a. It arrange | positions so that it may closely_contact | adhere to the inclined surface 353 formed in parallel so as to oppose the surface 253 (refer FIG. 3), and both inclined surfaces are pushed by pushing the ejector plate 22 in the mold closing direction with the drive bar 114 .... 243 and 353 are displaced from each other to slide the slide core 35a in the compression direction (the same applies to the other slide cores).

  The tip portions 251 and 252 having the inclined surface 253 of the compression bar 25a are formed in a plate shape whose width in the compression direction is 1.5 times or more larger than the width in the direction perpendicular thereto. A side surface on the compression direction side constitutes a sliding contact portion of the inclined surface 253. Then, as shown in FIG. 2 (B), the distal end portions 251 and 252 are pushed into the inside of the slide core 35a whose base end portion is formed in a square shape in plan view, so that both inclined surfaces 253 and 353 are formed. Are slid by pressing the slide core 35a in the compression direction while closely contacting each other (the same applies to other compression bars).

  Further, the compression operation is performed in a state in which more than half of the base end side of the side opposite to the compression direction of the compression bar 25 a is in sliding contact with the inner surface of the cavity side mold block 2. By configuring the movable means for sliding the slide cores 35a and 35b in the compression direction as described above, the compression bars 25a and 25b, which are the components, have excellent strength in the compression direction. Thus, even when the movable means in the mold block is configured with small parts in order to form a plurality of thin portions, each compression strength can be set high.

  Each of the slide cores 35a and 35b has a compression surface 351a on the distal end side and a plate-like pressing convex portion 351 to be inserted into the cavity 21 on the distal end side. A release bar 36a extending from the base side plate 3a (see FIG. 4) of the core side mold block 3 is provided at an intermediate position in the end where the distal ends 251 and 252 of the compression bars 25a and 25b are inserted. The tip end side of 36b is inserted, and as shown in FIG. 2 (B), these three parts are engaged with each other in a compact manner.

  Further, at the front end side of each release bar 36a, 36b, as will be described later, the slide cores 35a, 35b are retracted from the compression position to the pre-compression position to release the compression, thereby enabling the mold opening operation. Locking cams 361 and 362 formed with undercut inclined surfaces 361a and 362a (see FIG. 9) are projected, and inserted into corresponding portions of the slide cores 35a and 35b.

  Hereinafter, the construction and operation of each part will be described in detail while explaining the production procedure of the resin molded product by the partial compression molding die 1 of the present embodiment with reference to FIGS. FIG. 3 shows a state in which the partial compression molding die 1 is closed and the molten resin is injected and filled. .. Of a plurality of guide bars 39a, 39b... Shown by broken lines extending from the front end surface of the plate 3a. , 291b...

  At this time, although the ejector plate 22 is in the most retracted position, the compression bars 25a and 25b extending from the front end surface project the front end portions 251 and 252 from the mating surface 20 of the cavity-side mold block 2, respectively. In this state, the inclined surfaces 253 and 353 are in close contact with each other in the state of being inserted inside the slide cores 35a and 35b, and the release bars 36a and 36b extending from the distal end surface of the proximal end plate 3a The distal end side is inserted between the distal end portions 251 and 252.

  The pressing projections 351 of the slide cores 35a and 35b are opposed to each compression surface 351a at a position close to the side surface of the core 31 while inserting the distal end side into a slit formed so as to divide the cavity 21 radially. Thus, a thin portion is formed in the resin molded body 50 before solidification filled with the molten resin in the gap. The core 31 is provided with a resin introduction tube 38 penetrating the center thereof.

  FIG. 4 is an enlarged view of a portion surrounded by a two-dot chain line in FIG. 3, and the compression bar 25a has an inclined surface 353 formed on the inner side of the square shape of the slide core 35a. While closely contacting, the tip surface thereof is flush with the upper surface of the slide core 35a, and in this state, the gap X1 between the compression surface 351a at the tip of the pressing convex portion 351 and the side surface of the core 31 is larger than other portions. Although it is somewhat narrow (for example, 0.7 mm), it has a width that can be sufficiently filled with a molten resin at a normal injection pressure.

  Referring to FIG. 5, next, the drive bars 114,... Protruding from the electric injection molding machine are driven, and the ejector plate 22 is pushed in by a predetermined amount, whereby the compression bars 25a, 25b are core-side molds. The slide core 35a is slid in the compression direction while the inclined surface 253 and the inclined surface 353 that are inserted deeper into the block 3 and are in close contact with each other are displaced from each other.

  6 is an enlarged view of the portion surrounded by the two-dot chain line in FIG. 5. At this time, the compression surface 351a at the tip of the pressing convex portion 351 provided on the tip side of the slide core 35a and the side surface of the core 31 are shown. The gap X2 formed between them is smaller than the gap X1 in FIG. 4 (for example, 0.3 mm), and forms a thin portion having a desired thickness in the resin molded body 50 by the resin molded body 50 before solidification. (Other parts are the same).

  As described above, the pressing operation of the compression bars 25a and 25b is directly converted into the compression operation of the slide cores 35a and 35b, so that the ejector plate 22 is pressed by a drive source capable of precise control such as a servo motor. Accordingly, in combination with the fact that the inclination angle of the inclined surface 353 formed on each compression bar 25a, 25b is extremely gentle, each of the compression bars 25a, 25b can be controlled with a large compression force while precisely controlling the pushing operation. As a result, it is possible to accurately form a thin portion having a desired thickness in all portions.

  FIG. 7 shows a state where the ejector plate 22 is pulled back after the compression molding completion state of FIG. Thereby, although each compression bar 25a, 25b returns to the position before compression, since each slide core 35a, 35b remains in a compression position, mold opening operation cannot be performed as it is. Therefore, as shown in FIG. 8, a system is adopted in which the release bars 36a and 36b are pulled in the mold opening direction and the slide cores 35a and 35b are pulled back to the positions before compression by the locking cams 361 and 362 on the front end side. .

  That is, the core-side mold block 3 is formed by stacking a plurality of plates 3a, 3b, 3c, and the most proximal end plate 3a is fixed at the proximal end side to the electric injection molding machine side. In addition, a plurality of guide bars 39a,... And a plurality of release bars 36a, 36b are extended from the front end surface, and a predetermined range is opened and closed with the other plates 3b, 3c inserted therethrough. One block body is configured so as to be provided, and only the base side plate 3a is first opened by a predetermined width in accordance with the mold opening operation after molding.

  Then, as shown in FIG. 9 in which the portion surrounded by the two-dot chain line in FIG. 8 is enlarged, the locking cams 361 and 362 on the distal end side of the release bars 36a and 36b interlocked with the operation of the plate 3a are formed in an undercut shape The inclined surfaces 361a and 362a are displaced from each other while being in close contact with the inclined surfaces 350 formed at predetermined positions on the inner surfaces of the slide cores 35a and 35b, thereby pressing the slide cores 35a and 35b in the backward direction and before compression. Return to the position of.

  Then, by continuing the mold opening operation, as shown in FIG. 10, the large-diameter engaging portion formed on the distal end side of the predetermined one of the guide bars 39a,. By locking and opening the opening, and continuing the mold opening operation, as shown in FIG. 12, each locking portion of a predetermined one of the guide bars 39a,. The front end surface (matching surface 30) is locked to the opening and opened, and the mold is opened.

  Finally, as shown in FIG. 12, the ejector plate 22 is pushed further deeper than the compression shown in FIG. 5 to extend from the upper surface of the ejector plate 22 so that the tip side comes into contact with the lower part of the solidified resin molded body 100. The lift bar 29 lifts the resin molded body 100 as a resin molded product out of the cavity 21 and supports it at a position where it can be easily taken out, thereby completing the manufacturing process. In the above-described embodiment, the mode in which two slide cores face each other has been described. However, it goes without saying that the number of slide cores can be appropriately increased in the present invention, and the compression direction is also on the same plane. Can be set arbitrarily. For example, by arranging a large number (three or more) of slide cores radially with respect to the center of the core, it is possible to simultaneously provide a large number of thin portions with different angular positions and orientations on the outer peripheral surface of the cylindrical part.

  As described above, by using the partial compression molding die 1 of the present invention which is relatively compact but exhibits a relatively large compressive force at a plurality of different positions and directions, the apparatus / mold is used. Thus, a partially thin resin molded product having a plurality of thin portions can be manufactured with high accuracy without causing an excessive increase in size and an increase in cost.

  1 Partial compression molding die, 2 cavity side die block, 3 core side die block, 3a, 3b, 3c, 2a, 2b plate, 21 cavity, 22 ejector plate, 25a, 25b compression bar, 31 core, 35a , 35b Slide core, 36a, 36b Release bar, 39a, 39b Guide bar, 50, 100 Molded resin, 114 Drive bar, 253, 350, 353, 361a, 362a Inclined surface, 291a, 291b Insertion hole, 361, 362 Rocking cam

Claims (6)

A mold block on the core side and a mold block on the cavity side, and both mold blocks are closed with a predetermined injection molding machine, and the molding space is injected and filled with molten resin, and then one of the mold blocks By sliding a plurality of slide cores arranged on the core in a direction perpendicular to the mold opening / closing direction and toward the side of the core by a predetermined movable means, the resin molded body before solidification is partially compressed to form a plurality of thin portions In the partial compression molding mold to form
In the other mold block, a plurality of compression bars are extended from the front end surface in the mold closing direction, and a compression plate operable in the mold opening / closing direction by an external driving means is disposed inside. Each compression bar is inclined at a predetermined position of a slide member that is formed in a chamfered manner so as to face an oblique distal direction toward the distal end side and is in contact with each slide core or each slide core proximal end side. Each of the inclined surfaces is displaced from each other and the slide cores are slid in the compression direction by pushing the compression plate in the mold closing direction by the driving means. Mold for partial compression molding.   The resin molded body to be manufactured has an annular peripheral wall formed along the outer peripheral surface of the core, and the compression bars slide the slide cores in the center direction of the resin molded body, respectively. 2. The partial compression molding die according to claim 1, wherein the partial compression molding die is disposed on the compression plate in a position / direction of the inclined surface.   The front end portion of the compression bar having the inclined surface has a plate shape whose width in the compression direction is 1.5 times or more larger than the width in the direction perpendicular to the compression bar. The partial compression molding die according to claim 1 or 2, wherein a sliding contact portion of the surface is formed.   The compression bar is configured to perform a compression operation in a state where at least a base half of a side surface opposite to the compression direction side is in sliding contact with the inner surface of the mold block. Item 4. A partial compression molding die described in Item 3.   The other mold block is formed by stacking a plurality of plates, and the most proximal plate is fixed to the injection molding machine side at the proximal end side, and a plurality of plates from the distal end surface thereof. The guide bar and a plurality of release bars are extended, and the other plate is provided to be openable and closable within a predetermined range with the guide bar and the release bar inserted therethrough. In the mold opening operation after molding, the most proximal plate opens first, and an inclined surface formed in an undercut shape on the distal end side of the release bar interlocked with the plate is the slide core. The slide core is moved in a backward direction while being brought into close contact with the inclined surface formed at a predetermined position, and is returned to the position before compression. Parts engage, the will mold open state to open the other plate, partial compression mold according to claim 1, 2, 3 or 4, characterized in that.   The compression plate performs a push-in / retract operation by a drive bar inserted and connected from the injection molding machine side projecting / retracting by a driving force of an electric motor. A partial compression molding die described in 3, 4 or 5.

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