JP3849903B2 - Mold and molding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding die and a molding method suitable for use in injection molding of a resin material and the like, and more particularly to improvement of a protruding portion for releasing a molded product from a side gate type molding die.
[0002]
[Prior art]
A conventional example of a molding die using a resin material will be described with reference to FIGS. The molding die 1 shown in FIG. 6 employs a side gate method in which resin is injected from the side surface of the product, the spool 4 in the fixed die 2 and the movable die 3, the cavity 10 corresponding to the product shape, the resin Are formed from the sprue 4 into the cavity 10, and a gate 6 provided at the boundary between the cavity 10 and the runner 5 is formed. After molding by the molding die 1, the mold is opened, and then the ejector member 7 is driven to project the protruding pins 8 and 9 upward in the drawing, thereby releasing the molded product of the cavity 10 and the runner portion of the runner 5. Can be removed. The molded product thus obtained is shown in FIGS. 7 (a) and 7 (b). As shown in the figure, the thin plate-shaped molded product 14 includes a spool portion 4 ′ corresponding to the spool 4 of the molding die 1 and a runner portion 5 ′ corresponding to the runner 5 having a gate portion 6 ′ corresponding to the gate 6. Are connected through.
[0003]
As described above, in the side gate type molding die as shown in FIG. 6, when the molded product is taken out from the molding die, the molded product and the runner portion are connected and integrated. There is a problem that a post-processing step is required to separate them from each other, resulting in a decrease in production efficiency as a result of an increase in the number of steps.
[0004]
In addition, when molding a thin product (plate-like body), there is a pinpoint gate method in which resin is injected from the flat side of the product as a gate method other than the above-described side gate method in which resin is injected from the side surface of the product . In this pinpoint gate system, when the molded product is taken out from the mold, the molded product and the runner are separated, but there is a problem that the gate mark remains on the surface of the molded product and the appearance quality of the molded product is deteriorated.
[0005]
By the way, in a tape cartridge, a disk cartridge, or the like that stores a recording medium, a window member made of a translucent material may be disposed to see through the inside. When such a window member or the like is formed by injection molding using a pinpoint gate type molding die, a gate mark remains on the surface, so this gate method is not suitable for molding a window member or the like. In this case, it is often difficult to conceal the gate trace with other parts or make the design inconspicuous because the window member is translucent. For this reason, in order not to reduce the appearance quality of the molded product, the side gate method is preferable, but there is a problem of reduction in production efficiency.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problem, and even if a side gate method is adopted in a molding die, molding that can improve the production efficiency of molding without deteriorating the appearance quality of the molded product It is to provide a mold and a molding method.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a molding die of the present invention is formed of a fixed die, a movable die, a cavity and a runner formed between the fixed die and the movable die, and the cavity. A molded product projecting member for projecting the molded product at the time of mold release, a runner projecting member for projecting the runner portion formed by the runner at the time of mold release, and the molded product projecting member and the runner projecting member are integrated. A projection drive member that drives the molded product, wherein either one of the molded product projection member and the runner projection member is separated into a first projection member and a second projection member, The second projecting member is connected to the projecting drive member, and an urging member that is compressed during molding and restored when the mold is opened is interposed between the first projecting member and the second projecting member. Characteristic To.
[0011]
According to the molding die of the present invention, with the configuration of interposing a biasing member for restoring the to die opening when compressed during molding between the first projecting member and the second projecting member, during molding Due to the molding pressure, the first protruding member moves in the direction opposite to the protruding direction and the urging member is compressed. When the mold is opened in this state, the first protruding member is automatically generated by the restoring force of the urging member. Since the molded product or the runner portion protrudes and is released from the mold, the molded product and the runner portion can be automatically separated. In this way, the molded product and the runner portion can be easily separated by automatically projecting just by opening one of the molded product and the runner portion using the biasing member. This eliminates the need for a post-processing step for separating the molded product from the runner, and can improve the production efficiency of the molding. Also, a side gate type molding metal that injects resin from the side surface of the molded product. By applying the present invention to a mold, a molded product having no gate marks and good appearance quality can be obtained. Moreover, the other mold release of a molded article and a runner part can be performed by protruding and projecting a drive member.
[0012]
Further, the molding method of the present invention is a method of molding using a molding die provided with the above-described urging member, the step of filling the cavity with a molding material via the runner, and the molding die A step of opening the mold, and when the urging member compressed in the filling step is restored in the mold opening step, the first protruding member causes either one of the molded product and the runner part to be restored. The molded product and the runner portion are separated by protruding and releasing from the mold. According to this molding method, the urging member is compressed due to the molding pressure at the time of molding, and when the mold is opened in this state, the molding pressure is released, and the first protrusion is automatically made by the restoring force of the urging member. The member protrudes and releases one of the molded product or the runner portion, and the molded product and the runner portion are automatically separated. In this way, the molded product and the runner can be easily separated by simply opening one of the molded product and the runner using the biasing member, and the molded product and the runner can be easily separated. Therefore, post-processing for separating the molded product and the runner portion is unnecessary, and the production efficiency of molding can be improved. In addition, by using a side gate system as the molding die, a molded product with no appearance of gate and having good appearance quality can be obtained .
[0013]
Further, when the protruding drive member protrudes from the first protruding member and then moves in the direction opposite to the protruding direction, the first protruding member returns so that the protruding first protruding member returns to the original position. The urging member for urging can be arranged. According to this, when the projecting drive member projects the first projecting member and returns to the original position before projecting, the first projecting member can be automatically returned to the original position by the biasing member. Since it can be quickly clamped and moved to the next molding, it can contribute to the improvement of production efficiency.
[0014]
Further, by providing a plurality of the molded product projecting member and the runner projecting member, the molded product and the runner portion can be ejected and released while being securely held. The number of protruding members can be determined as appropriate depending on the shape of the molded product and the runner portion.
[0015]
In this case, the second projecting member is provided as a single unit, and a connecting member is provided to be connected to the single second projecting member, and a plurality of the first projecting members are connected to the projecting drive member via the connecting member. It can comprise so that it may drive. Thereby, even if there are a plurality of first projecting members, the second projecting member can be configured as a single unit. Therefore, the number of parts of the molding die can be reduced, and the mold cost can be reduced. The biasing member can be arranged and held.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
< Reference example >
FIG. 1 is a longitudinal sectional view showing a main part of a molding die of a reference example relating to the present embodiment , and FIG. 2 is a longitudinal sectional view showing a movable side die in a state where the molding die of FIG. 1 is opened after molding. FIG. The molding die 11 shown in the figure has a cavity shape corresponding to the shape of a molded product formed between a stationary die 12 including a core portion 18, a movable die 13 including a core portion 19, and core portions 18 and 19. A cavity 16, a runner 15 formed between the core portion 18 and the core portion 19 and connected to the cavity 16 via a gate 16a, and a spool 14 connected to the runner 15 and having a resin injection port 14a are provided. Further, the fixed mold 12 and the movable mold 13 are combined on the mating surface 23 and clamped so as to be moldable. FIG. 1 shows a state where the cavity 16, the runner 15 and the spool 14 are filled with molding resin, and the cavity 16 has a hollow shape for molding a thin plate member.
[0018]
The molding die 11 is further disposed in the core portion 19 of the movable die 13 through a hole provided in the vertical direction in the drawing, and the runner portion formed in the runner 15 at the time of molding is separated from the upper portion of the drawing for mold release. A plurality of runner protruding pins 20 protruding in the same manner, a plurality of molded product protruding pins 21 protruding in the same manner and formed in the cavity 16 for releasing, and the runner protruding pins 20 and the molded product protruding pins 21. An ejector member 17 that is connected and driven to protrude upward in the drawing is provided.
[0019]
Each runner protruding pin 20 is configured to be separated into a core pin 20 a penetrating the core portion 19 and a protruding pin 20 b connected and fixed to the ejector member 17. Each core pin 20a is configured such that its tip 20c abuts on the runner portion, and a pedestal portion 20d at its lower end is placed on the upper surface of the core pin receiving member 24 disposed between the core portion 19 and the ejector member 17. Yes. Each protruding pin 20b is positioned such that its tip 20e faces the lower surface of the pedestal 20 of the core pin 20a in a through hole formed in the core pin receiving member 24. A gap 25 is formed in each hole of the core pin receiving member 17 and between the tip 20e of each protruding pin 20b and the pedestal 20d of each core pin 20a at the molding position in FIG.
[0020]
A coil spring 22 is disposed around each core pin 20a between the lower surface of the core portion 19 and the upper surface of the pedestal portion 20d of the core pin 20a. When the core pin 20a moves upward, the coil spring 22 is compressed, so that a force pushing the core pin 20a downward acts. The tip 20c of each core pin 20a is positioned in the hole of the core portion 19 at the molding position in FIG. 1, and therefore, in the runner portion 15 ′ (shown in FIG. 2) formed by the runner 15. A leg portion 15 ″ having a shape corresponding to the hole of the core portion 19 is formed.
[0021]
The molding process using the molding die 11 will be described. The molten resin from the resin injection port 14a of the stationary mold spool 14 shown in Figure 1 was injected at high pressure, the spool 14, the runner 15, filled through the gate 16a into the cavity 1 in 6. After the filled resin is solidified and cooled, the movable mold 13 is moved downward along the guide pins 26 of the fixed mold 12 to open the mold.
[0022]
Next, when the ejector member 17 is driven by a drive source (not shown) and moved upward in FIG. 1, a plurality of molded product protruding pins 21 connected and fixed to the ejector member 17 are moved upward and protruded. Then, by pushing up the molded product 16 ′ (shown in FIG. 2) formed in the cavity 16, the molded product 16 ′ is lifted upward and released. Simultaneously with the operation of the molded product projecting pin 21, the ejector member 17 drives the projecting pins 20b of the plurality of runner projecting pins 20 to move upward in the figure, but their tips 20e are pedestal portions of the core pins 20a. Because of the gap existing between the lower surface of 20d, the core pins 20a do not move because they do not immediately contact the lower surface of the pedestal portion 20d. Therefore, before the runner portion 15 ′ (shown in FIG. 2) formed on the runner 15 is projected to the core pin 20 a of the plurality of runner projecting pins 20, the molded product projecting pin 21 causes the molded product 16 as described above. When 'is protruded, the molded portion corresponding to the gate 16a is bent and cut. In this way, the molded product 16 ′ and the runner portion 15 ′ are separated as shown in FIG.
[0023]
Subsequently, when the ejector member 17 is further moved upward in the drawing, each protruding pin 20b moves in the gap 25, and its tip 20e comes into contact with the lower surface of the pedestal portion 20d of each core pin 20a as shown in FIG. Then, by further moving the ejector member 17, each core pin 20a moves upward while compressing the coil spring 22, and its tip 20c pushes up the leg portion 15 "of the runner portion 15 ', thereby causing the runner portion 15 to move upward. The runner 15 'with the spool 14' and the molded product 16 'separated in this manner can be taken out from the mold 11.
[0024]
After the molded product or the like is released as described above, the ejector member 17 moved upward returns to the position shown in FIG. 1 together with each protruding pin 20b by the restoring force of the coil spring disposed on the return pin 27. Each core pin 20a is automatically returned to the position shown in FIG. 1 with its pedestal 20d pushed downward by the restoring force of the compressed coil spring 22. Accordingly, it is possible to quickly shift to a process such as mold clamping for the next molding, and therefore, it is possible to shorten the molding cycle time and contribute to an improvement in molding production efficiency, which is preferable.
[0025]
As described above, according to the molding die shown in FIGS. 1 and 2 , the runner protruding pin 20 is separated and the gap 25 is provided between them, so that the molded product protruding pin 20 is ejected when the mold is opened after molding. Can be performed faster than the runner protruding pin 21. By shifting the operation timing of the two in this way, the runner portion 15 ′ and the molded product 16 ′ can be easily separated in the step of releasing by extrusion, so that the molded product can be separated from the molded product after release as in the prior art. A post-processing step for removing the runner and the like is not necessary. For this reason, the molding process can be simplified, the execution thereof becomes easier, and the time required for the molding process can be shortened, so that the production efficiency of molding can be improved. In addition, since the molding die 21 uses a side gate method, the molded product 16 ′ has almost no gate trace and is not noticeable. For example, the light transmission in a tape cartridge or a disk cartridge containing a recording medium is used. Even if a window member or the like made of a conductive material is molded, its appearance quality does not deteriorate. The difference in operation timing between the protruding pins 20 and 21 can be adjusted by changing the interval of the gap 25.
[0026]
<Embodiment>
3 is a longitudinal sectional view showing a main part of the molding die according to the embodiment of the present invention, and FIG. 4 is a longitudinal sectional view showing a state in which the molding die shown in FIG. 3 is filled with a resin material. FIG. 5 is a longitudinal sectional view showing a movable side mold in a state where the mold of FIG. 4 is opened after molding. Since the basic configuration of the molding die shown in FIG. 3 is the same as that of FIG. 1, the same parts are denoted by the same reference numerals, and the description thereof is omitted.
[0027]
As shown in FIG. 3, in the molding die 31 of the present embodiment, the runner protruding pin 20 is provided separately into a plurality of core pins 20a and a single protruding pin 20b. The lower end of the single protruding pin 20b is connected and fixed to the ejector member 17, and the upper end 20e is connected and fixed to the core pin receiving plate 32. The core pin receiving plate 32 is driven by the ejector member 17 through a single protruding pin 20b. A plurality of protruding pins 20b may be provided corresponding to the plurality of core pins 20a.
[0028]
A plurality of small diameter pins 20 f are fixedly provided on the upper surface of the core pin receiving plate 32. A gap 35 is formed between each small-diameter pin 20f and the lower surface of the pedestal portion 20d of each core pin 20a. A coil spring 33 is positioned by each small-diameter pin 20f and is disposed between the upper surface of the core pin receiving plate 32 and the lower surface of the pedestal portion 20d. In the molding position shown in FIG. 3, each core pin 20 a is pushed by the coil spring 33 and its upper end 20 c is positioned so as to be slightly recessed in the hole of the core portion 19.
[0029]
The molding process using the molding die 31 will be described. The molten resin from the resin injection port 14a of the stationary mold spool 14 shown in FIG. 3 was injected at high pressure, the spool 14, the runner 15, filled through the gate 16a into the cavity 1 in 6. At this time, the resin is also filled in each hole of the core portion 19, and the core pin 20 a is pushed downward from the tip 20 c by the pressure at the time of filling, and the lower surface of the pedestal portion 20 d is in the gap 35. The coil spring 33 is compressed and pushed down to the vicinity of the upper end of each small-diameter pin 20f on the upper surface of the core pin receiving plate 32 as shown in FIG. After the resin filled in this state is solidified and cooled, the movable mold 13 is moved downward along the guide pins 26 of the fixed mold 12 to open the mold.
[0030]
When the mold 31 is opened as described above, the molding pressure applied to the runner 15 and the like is released. Then, each coil spring 33 pushes back each core pin 20a upward in an attempt to recover from the compressed state. As a result, the tip 20c of each core pin 20a pushes up the leg portion 15 ″ of the runner portion 15 ′, whereby the runner portion 15 ′ is lifted upward as shown in FIG. 5 to release the mold. Since the molded product protruding pins 21 do not move because they are not driven yet, before the molded product 16 ′ formed in the cavity 16 is protruded by the molded product protruding pins 21, the core pin 20 a of the runner protruding pin 20. Thus, when the runner portion 15 ′ is protruded as described above, the molded portion corresponding to the gate 16a is bent and cut, and thus the molded product 16 ′ and the runner portion 15 ′ as shown in FIG. Note that when the runner portion 15 ′ is protruded as described above, the leg portion 15 ″ remains in each hole of the core portion 19 as shown in FIG. By determining the overall length, the length of the coil spring 33, and the like, the runner portion 15 ′ can be prevented from unexpectedly dropping from the molding die 21 before releasing the molded product 16 ′.
[0031]
Subsequently, by moving the ejector member 17 upward in the figure, the molded product protruding pin 21 pushes up and lifts the molded product, thereby releasing the molded product 16 ′. At the same time, each core pin 20a is also moved upward via the protruding pin 20b, the core pin receiving plate 32, and the coil spring 33 to push out the leg portion 15 ″ of the runner portion 15 ′, thereby completely forming the molded product 16 ′ and the runner portion 15 ′. can be extracted. each core pin 20a as described above moves upward, if the tip 20c projects beyond mating face 23, when the stationary mold 12 side during clamping for the next molding Therefore, it is desirable that each tip 20c is configured not to protrude from the mating surface 23.
[0032]
As described above, according to the molding die according to the present embodiment, the runner protruding pin 20 is separated and the coil spring 33 is provided therebetween, so that the coil compressed by the molding pressure when the mold is opened after molding. By utilizing the restoring force of the spring 33, the projecting operation of the runner projecting pin 21 can be performed earlier than the projecting product projecting pin 20. In this way, by shifting the operation timing of both, the runner 15 'and the molded product 16' can be easily separated simply by opening the mold after molding in the step of releasing by extrusion, As in the prior art, a post-processing step for removing the runner and the like from the molded product after mold release is not required. For this reason, the molding process can be simplified, the execution thereof becomes easier, and the time required for the molding process can be shortened, so that the production efficiency of molding can be improved.
[0033]
In the present embodiment, various resin materials can be used, but a resin material that breaks relatively brittlely such as PS (polystyrene), AS, ABS, PMMA or the like is preferable. The gates 16a of the molding dies 11 and 31 can have various shapes such as a circle, a semicircle, and a rectangle. However, in order to ensure the separation performance between the molded product and the runner, the width and length are A relatively short length is preferable.
[0034]
Was described using the embodiments of the present invention as described above, but the present invention is not limited thereto, various modifications are possible. For example, the molded product protruding pin side may be separated to have the same configuration as shown in the figure, and can be applied to a gate system other than the side gate system.
[0035]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the process for isolate | separating a molded article becomes unnecessary, and the molding die and molding method which can improve the production efficiency of shaping | molding can be provided. In addition, since the side gate method can be adopted in the molding die, the appearance quality of the molded product does not deteriorate.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a main part of a molding die of a reference example relating to the present embodiment .
2 is a longitudinal sectional view showing a movable mold in a state where the mold of FIG. 1 is opened after molding.
FIG. 3 is a longitudinal sectional view showing a main part of a molding die according to an embodiment of the present invention.
4 is a longitudinal sectional view showing a state in which the molding die shown in FIG. 3 is filled with a resin material. FIG.
5 is a longitudinal sectional view showing a movable side mold in a state where the mold of FIG. 4 is opened after being molded. FIG.
FIG. 6 is a longitudinal sectional view showing a main part of a conventional molding die.
7 is a longitudinal sectional view (a) and a plan view (b) showing a molded product and a runner formed by the molding die shown in FIG. 6. FIG.

Claims (4)

A fixed mold, a movable mold, a cavity and a runner formed between the fixed mold and the movable mold, and a molded product protruding member for projecting a molded product formed by the cavity at the time of mold release A runner projecting member for projecting the runner formed by the runner at the time of mold release, and a projecting drive member that integrally drives the molded product projecting member and the runner projecting member. There,
Together with the one of the molded article ejection member and the runner projecting member configured to the first projecting member to separate the second projecting member, connecting the second protruding member in the projecting drive member, the A molding die characterized in that an urging member that is compressed during molding and restored when the mold is opened is interposed between the first projecting member and the second projecting member . The molding die according to claim 1, wherein a plurality of the molded product protruding members and the runner protruding members are provided. A single second projecting member is provided, and a connecting member connected to the single second projecting member is provided, and a plurality of the first projecting members are driven by the projecting drive member via the connecting member. The molding die according to claim 2 configured to be configured as described above. It is a method of shape | molding using the shaping die of any one of Claim 1 thru | or 3 , Comprising: The process which fills the said mold material with the said cavity via the said runner, and the said mold is opened. The biasing member compressed in the filling step is restored in the mold opening step, so that the first protruding member protrudes and separates either the molded product or the runner portion. A molding method characterized by molding and separating the molded product and the runner part.

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