JP2013049141A - Method and device for manufacturing molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely remove air bubbles in a liquid material (rubber material, for instance) to be injected into a molding mold when manufacturing a molded product (mold for a template, for instance).SOLUTION: The lowest portion in a molding space formed between a prototype 1 and a backing member 2 and a trough-like container 4 are connected by a communication passage 20 and the communication passage 20 is set to a closed state by an opening/closing member 5 mounted in the trough-like container 4. The liquid rubber material G of a required amount is injected into the trough-like container 4 and stayed once. Subsequently, the communication passage 20 is set to an opened state by the opening/closing member 5 to make the rubber material G flow into the molding space by an action of gravity and the rubber material G is filled in the molding space.

Description

  The present invention relates to a method of manufacturing a molded product that is molded by injecting a liquid material into a prototype and a manufacturing apparatus thereof.

  A method of manufacturing various molded products using a resin material or a metal material using a prototype has been put into practical use. As an example of a molded product, for example, in a method for casting a tire molding die, a prototype blade for forming a sipe is attached to a prototype in which a pattern of a tread portion of a tire is formed, and a mold obtained by transferring the prototype to which the blade is attached Manufacturing a rubber mold for taking is carried out. The reason why the rubber mold is used for the mold for the mold is that the rubber mold has an appropriate elasticity and even if there is a so-called undercut shape in which the draft is reversed when the molded product is removed, This is because molding is possible and the shape transfer accuracy is high.

In the molding of a rubber mold for molding, a processing method by molding (cast molding) using a liquid rubber material is employed.
FIG. 5 is a diagram for explaining each step in a conventional method for producing a rubber mold for molding.
With reference to FIG. 5, a rubber mold (molding rubber mold) used for casting manufacture of a molding mold for a tire equipped with a sipe will be described among conventional molding rubber molds.
First, a prototype blade 100a for sipe molding is attached to the prototype 100. As shown in FIG. 5A, the prototype blade 100a is attached or implanted in a groove 100b (see FIG. 7) of the prototype 100. FIG. 5B is a cross-sectional view showing a state in which the prototype blade 100 a is attached to the prototype 100. Subsequently, as shown in FIG. 5C, the master 100 with the master blade 100a is transferred to the rubber mold 110 for molding. Next, the transferred mold mold rubber mold 110 is removed, and the mold blade 110a is replanted into the groove formed by the prototype blade 100a as shown in FIG. 5D. Subsequently, the template transfer shown in FIG. 5E is performed. At the time of this mold transfer, the mold blade 110a attached to the mold-taking rubber mold 110 is transferred to the mold 120, and the mold 120 with the mold blade 110a (collapseable mold) is obtained.

FIG. 5F is a cross-sectional view showing a state where the mold 120 is removed.
Subsequently, as shown in FIG. 5G, mold finishing is performed to remove burrs of the mold 120 with the correction tool 125. Next, the mold 120 is dried and fired as shown in FIG. 5H, and the mold 130 is cast using the mold 120 as shown in FIG. 5I. When the mold 130 is cast, the mold blade 110a is moved to the mold 130, and the mold is separated as shown in FIG. 5J to obtain the mold 130 attached with the mold blade 110a shown in FIG. 5K.

In the tire casting mold casting method described above, the process of transferring the molding rubber mold will be described with reference to FIG.
First, the prototype 100 with the prototype blade 100a is prepared. As for the rubber material to be injected into the prototype 100, a main material, a curing agent, and the like are prepared at a predetermined blending ratio and then stirred and degassed under reduced pressure. In order to inject the rubber material into the prototype 100, first, the frame body 101 is closely attached around the prototype 100 to which the prototype blade 100a is attached so as not to leak, and the upper surface of the prototype 100 is surrounded by the frame body 101. The rubber material G is injected into the formed space.

  The rubber material G fills the upper surface of the prototype 100 without a gap, but the air entrained at the time of injection becomes bubbles B and is formed inside the rubber material G (FIG. 6A). The prototype 100 into which the rubber material G has been injected is set in the decompression chamber 102 of the decompression device and subjected to a decompression defoaming process, and the bubbles B in the rubber material G are removed (FIG. 6B). After the vacuum degassing treatment, the backing member 103 is fitted into the frame body 101 and set above the master 100 (FIG. 6C). A large number of air vent holes 103a are formed in the backing member 103 so as to fill the cavity with the rubber material G while venting air in the cavity between the prototype 100 and the backing member 103 from the air vent hole 103a. In this state, the rubber material is cured (FIG. 6D).

  At that time, air that cannot be extracted from the air vent hole 103 a remains as an air reservoir C on the lower surface of the backing member 103. After the rubber material G is cured, the frame body 101 is removed from the original mold 100, and the molding rubber mold 110 in which the backing member 103 and the cured rubber material are integrated is removed (FIG. 6E). In this way, the mold making rubber mold 110 is formed (FIG. 6F).

  By the way, in the production of the conventional mold-making rubber mold 110, since the backing member 103 is set after degassing under reduced pressure, it is inevitable that the air pocket C remains in the molded mold-molding rubber mold 110. There is a possibility of causing a dimensional defect of the rubber mold 110 for removing. Further, as shown in FIG. 7, the prototype blade 100a is implanted in the groove 100b formed in the prototype 100, or the prototype blade 100a is attached to the surface of the prototype 100 as shown in FIG. Attached. Therefore, a minute gap is formed at the attachment location of the prototype blade 100a, and the liquid rubber material injected into the gap enters so as to be inserted.

For example, as shown in FIG. 7, when the prototype blade 100a is implanted, the rubber material enters the minute gap (FIG. 7A (3)) between the groove 100b formed in the prototype 100 and the prototype blade 100a. Then, the rubber burr 100c is formed so as to protrude around the groove 100b of the rubber mold 110 for molding formed corresponding to the blade for prototype 100a (FIGS. 7B (1) and (2)).
7A (1) shows a state before the prototype blade 100a is implanted in the groove 100b of the prototype 100, FIG. 7A (2) shows the implanted state, and FIG. 7A (3) shows the implanted state. It is sectional drawing of a state. 7B (1) shows a state in which the rubber burrs 100c are generated when the prototype blade 100a is implanted in the groove 100b of the prototype 100, and FIG. 7B (2) shows the occurrence of the rubber burrs 100c in the rubber mold 110 for molding. It is a figure which shows a state.

Further, as shown in FIG. 8, even when the prototype blade 100a is attached to the prototype 100, the rubber material enters the minute gaps (minute dents) around the prototype blade 100a to form the rubber burr 110c. . These rubber burrs 110c must be removed manually after demolding, which is a factor of reducing production efficiency.
8A (1) is a state before the original blade 100a is attached to the original 100, FIG. 8A (2) is a view showing the attached state, and FIG. 8 (3) is the attached state. FIG. 8B (1) shows a state where the rubber burrs 110c are generated when the prototype blade 100a is attached to the prototype 100. FIG. 8B (2) shows a state where the rubber burrs 110c are generated in the rubber mold 110 for molding. FIG.

  As a method similar to the molding method in the method for producing a molded product of the present invention described below, when a roller-shaped body such as a solid tire is manufactured, the molding die is set in an inclined state, and the molding die The liquid material is injected from the injection hole formed in the vicinity of the top of the cylindrical cavity inside, and the air release hole of the injection hole is provided at one side on both sides, and the liquid material is allowed to escape into the cylindrical cavity by gravity. However, a molding method is known that is filled and cured (Patent Document 1).

  However, in Patent Document 1, the above-described blade is not attached to form a complicated shape such as a sipe, and depending on this, it is difficult to perform highly accurate forming.

As another conventional example, in a gravity casting method in which molten metal is sequentially filled from a cavity to a feeder via a plurality of runners in a casting mold cavity, the runner is blocked by a shielding plate or the like. There is known a molding method in which the molten metal path is changed (see Patent Document 2).
In this molding method, the amount of molten metal filled is detected by the hot water amount detecting means, and the runner portion near the product part is shut off by the shutting means via the control device based on the detection value of the hot water amount detecting means. The molten metal hot water supply route is changed to the branch runner and is filled in the cavity of the product part and the hot water feeder, so that the molten metal is cut off from the runner and the branch runner Will flow into the cavity of the product part. Therefore, the filled molten metal is gradually filled from the cavity of the product part into the feeder part, preventing the “overheating phenomenon” of the gypsum mold and preventing product defects and stabilizing the quality. It is.
However, the molding method described in Patent Document 2 does not solve the above-described problems such as the formation of burrs associated with the molding of the conventional rubber mold.

JP 2002-127161 A JP 2008-93729 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a molded product and an apparatus for manufacturing the same that can reliably remove bubbles in a liquid material injected into a mold.

The present invention relates to a method for manufacturing a molded product by manufacturing a molded product by injecting a liquid material into a molding space in a molding die and filling it with gravity, and connecting a staying portion in the vicinity of the lowermost portion of the molding space. A step of setting the communication path to a closed state, a step of injecting and retaining a required amount of the liquid material in the retention portion, and then opening the communication path to allow the liquid material to flow into the molding space by gravity. And a filling process.
Further, the present invention provides a molding die in which a molding space filled with a liquid material is formed, a staying part for injecting and retaining a required amount of the liquid material, and the staying part in the vicinity of the lowermost part of the molding space. It is an apparatus for manufacturing a molded article, which includes a communication path to be connected and an opening / closing means for opening and closing the communication path.

  According to the present invention, the liquid material to be injected is once retained in the retention portion to remove bubbles in the liquid material, and then the liquid material is allowed to flow into the molding space in the mold. Air bubbles can be reliably removed.

It is a top view regarding the manufacturing apparatus of the molded article which is embodiment of this invention. It is AA sectional drawing of FIG. It is explanatory drawing regarding each process of the manufacturing method of the molded article of this embodiment. It is a figure explaining the manufacturing method of the molded article further simplified. It is a figure explaining each process in the manufacturing method of the conventional rubber mold for shaping. It is a figure explaining the transfer process of the conventional rubber mold for mold taking. It is a figure explaining how the burr | flash comes out when the blade for prototypes is implanted in the conventional prototype. It is a figure explaining how to produce the burr | flash in the case of affixing the braid | blade for prototypes on the conventional prototype.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a molded product manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG. This embodiment is an apparatus for molding a molding rubber mold used for manufacturing a tire molding mold as a molded product.
The molding die is configured such that the original mold 1 and the backing member 2 are arranged at a predetermined interval, and the periphery is closely fixed by a frame body 3. On the mold surface facing the backing member 2 of the prototype 1, the prototype blade is formed in a shape corresponding to a part of the tread surface of the tire and corresponds to a plurality of sipes formed in the width direction of the tread surface. 10 is attached so that it may protrude. The prototype blades 10 are arranged above and below the tread surface of the mold, the upper prototype blade 10 is implanted and attached in the prototype 1, and the lower prototype blade 10 is attached to the mold surface of the prototype 1. It is attached.

A ring-shaped anchor member 21 is attached to the mold surface of the backing member 2 facing the original mold 1 so as to protrude in order to improve the adhesion to the rubber material. On the lower surface of the backing member 2, a stepped groove is formed toward the prototype 1, and a communication path 20 is formed between the groove and the frame body 3.
Outside the backing member 2 is provided a bowl-like container 4 for injecting and retaining a liquid material (here, a rubber material). The bowl-shaped container 4 is formed such that an upper opening 40 protrudes upward from the mold and expands, and a tubular section 41 having a rectangular cross section is extended below the opening 40. The outer side surface of the tubular portion 41 is in close contact with the outer surface of the backing member 2, and the lower end portion of the tubular portion 41 is firmly fixed to the frame body 3.

  The lower end portion of the tubular portion 41 is connected to the communication path 20 with a part of the side surface contacting the outer surface of the backing member 2 being cut away. Therefore, the rubber material injected into the bowl-shaped container 4 flows into the communication path 20 without being leaked and is introduced into the mold. An opening / closing member 5 made of a belt-like plate material is attached to the inner surface of the tubular portion 41 on the backing member 2 side. The opening / closing member 5 is attached so as to be movable in the vertical direction along the inner surface of the tubular portion 41. When the opening / closing member 5 is moved downward and the lower end portion is in contact with the surface of the frame body 3, the communication path 20. In a state where the liquid material does not flow in and the opening / closing member 5 is moved upward, the communication path 20 is set in an open state and the liquid material flows in.

  The molding die is formed with a molding space between the opposing mold surfaces of the original mold 1 and the backing member 2, and is formed on the upper surface of the support base 6 so that the width direction of the tread surface of the mold surface of the original mold 1 is the vertical direction. is set up. The molding space in the mold is connected to the communication passage 20 in the vicinity of the lowermost portion thereof, so that the rubber material flows from the communication passage 20 into the molding space from the lowermost portion so that the liquid level gradually rises. It will be done.

  An air vent hole 30 is formed in the upper part of the frame 3 along the molding space of the original mold 1 and the backing member 2, and when the liquid material flows into the molding space from the lowermost part, the air vent hole 30 is molded. The air in the space is exhausted and removed. The support base 6 includes a plurality of support legs 7, and each support leg 7 is provided with an adjustment mechanism for adjusting the height. Therefore, by appropriately adjusting the height of each support leg 7, the mold placed on the upper surface of the support base 6 can be set in a state inclined forward with respect to the vertical direction.

In addition, as a mechanism which adjusts the inclination state of the support stand 6, the axis | shaft which supports the support stand 6 may be provided, and a shaft may be rock | fluctuated, It is not limited to the mechanism mentioned above.
As in this embodiment, by tilting the mold forward, the air between the mold surface of the mold and the liquid surface of the inflowing liquid material travels along the mold surface and escapes to the outside. So that it can be filled with liquid material.
Therefore, formation of an air pocket at the time of filling can be prevented.

In the embodiment described above, the communication path 20 is formed on the lower surface of the backing member 2, but it may be formed on the lower surface of the prototype 1 and if connected to the lowermost part of the molding space, It can also be provided in other locations, and is not particularly limited to the above embodiment.
The opening / closing member that opens and closes the communication path 20 may be configured to open and close the communication path 20 using a known means such as a gate or a valve member that can be moved in and out of the communication path 20. Is not particularly limited.

The bowl-shaped container may also be disposed at a place other than the outside of the backing member 2 and connected to the communication path in a container shape in which the liquid material is once retained and the molding space can be filled with the rubber material by the action of gravity. It can be used if possible.
In addition, although the anchor member 21 is provided on the mold surface of the backing member 2, the adhesiveness to the rubber material can be improved by applying an adhesive in advance instead of the anchor member 21.

  FIG. 3 is an explanatory diagram relating to a manufacturing process by a method for manufacturing a molded product (cast molding method) according to the present embodiment. First, similar to the conventional method described in FIG. 5, a known material such as a urethane material, a polysulfide material, and a known material such as a curing agent, which are raw materials of rubber material, are mixed at a predetermined blending ratio and stirred. To degas under reduced pressure to prepare a liquid rubber material. The molding die is adjusted to a state in which the support base 6 is inclined so that the tread surface which is the mold surface of the original mold 1 is slightly upward (forwardly inclined). After the opening / closing member 5 is moved downward to set the communication path 20 in a closed state, the prepared rubber material G is poured into the bowl-shaped container 4 (FIG. 3A). The amount of the rubber material G to be injected is an amount obtained by adding an amount necessary for filling the molding space to an amount necessary for filling the bowl-like container 4 up to a position substantially the same height as the air vent hole 30. It is good to set.

  When injecting the rubber material, the rubber material G is poured so as to travel along the side surface of the opening / closing member 5, so that bubbles can be prevented from being involved in the injected rubber material G as much as possible. The injected rubber material G reaches the lower end of the bowl-shaped container 4 through the opening / closing member 5, but stays in the bowl-shaped container 4 because the communication path 20 is closed by the opening / closing member 5. To go.

  At that time, even if there are bubbles entrained in the rubber material G, the bubbles are gradually separated and floated by being left standing in the bowl-shaped container 4 for a predetermined time, so that the bubbles in the bowl-shaped container 4 It is discharged outside through the opening. Further, even when bubbles remain in the rubber material G, the bubbles separate and float on the upper portion of the rubber material G, and no bubbles remain in the lower portion of the rubber material G. If bubbles are collected in the upper portion and the degassing process is performed, the bubbles can be easily and reliably removed from the rubber material G.

  Further, even if bubbles remain in the rubber material G, as long as the bubbles are not contained in the rubber material G staying in the lower part of the bowl-like container 4 filled in the molding space, as will be described later. In this case, the vacuum defoaming treatment is not required, and the production of a mold product by a simple molding method, for example, a mold taking rubber mold can be realized.

  Next, after a required amount of the rubber material G is injected into the bowl-shaped container 4 to remove bubbles, the opening / closing member 5 is moved upward to set the communication path 20 open (FIG. 3B). By opening the communication path 20, the rubber material G staying in the bowl-shaped container 4 is introduced into the communication path 20 and flows into the interior from the lowermost part of the molding space. In this case, the rubber material G continuously flows into the molding space due to the action of gravity, and as the molding material is filled with the rubber material G, the liquid level of the rubber material G in the molding space gradually rises. To go. At that time, since the tread surface of the prototype 1 is set slightly upward (inclined forward), as the liquid level of the rubber material G rises, air such as grooves on the tread surface escapes and air There is no accumulation. That is, if the uneven surface such as a groove on the tread surface is facing downward, an air pocket is likely to be generated between the uneven surface and the rising liquid surface. By keeping the facing upward, it is possible to prevent the occurrence of such air pockets.

  In addition, as the liquid level of the rubber material G rises, the inclined state of the mold can be changed to prevent the occurrence of air accumulation. In this case, a transparent plate-like body such as an acrylic plate is used as the frame 3, and the mold is inclined so as not to generate air pockets while observing the liquid level of the rubber material G rising in the molding space with the naked eye. By adjusting the state, the occurrence of air pockets can be reliably prevented.

  As described above, in the molding space, the liquid level gradually rises with the inflow of the rubber material G, and the air in the molding space is discharged from the air vent hole 30. And when the liquid level of the rubber material G rises to the air vent hole 30 and leaks, the position becomes substantially the same as the liquid level of the rubber material G in the bowl-shaped container 4. Thereby, the inflow of the rubber material G into the molding space is stopped, and the filling of the rubber material G is completed (FIG. 3C).

  In this case, since the width direction of the tread surface of the mold surface of the prototype 1 is set to be the vertical direction, the prototype blades 10 attached corresponding to the sipe are arranged along the vertical direction. Even when the liquid level of the rubber material G rises, the rubber material G is filled without causing air accumulation around the prototype blade 10.

  In addition, since the rubber material G is once retained and the bubbles are removed, and then the rubber material G is filled in the molding space, it is not necessary to perform a vacuum degassing process after the rubber material G is filled. Therefore, as in the prior art shown in FIG. 5, a rubber burr is formed by entering the rubber material G so as to be inserted into a minute gap around the blade by performing a vacuum degassing treatment after filling the rubber material G. In addition, it is not necessary to remove rubber burrs after molding, and production efficiency can be improved.

  After the rubber material G is filled into the molding space, the filled rubber material is cured, and after the rubber material is cured, the frame 3 is removed from the original mold 1 and the backing member 2 is filled, as in the conventional process shown in FIGS. The mold-making rubber mold in which the cured rubber material is integrated is removed. As a result, a rubber mold which does not contain bubbles and does not generate rubber burrs can be obtained.

  FIG. 4 is an explanatory diagram relating to a further simplified method of manufacturing a molded product. In this method, the molding die is set in a state of being tilted forward, and the rubber material G is directly injected into an opening opened above the molding space. When injecting, if the rubber material G flows into the mold surface of the prototype 1 while flowing down, it is possible to fill the rubber material G while avoiding as much bubbles as possible in the rubber material G during injection. . Also, the entrained bubbles come to separate and float while the liquid level of the rubber material G is rising, and it is possible to suppress the remaining bubbles as much as possible.

  A molding rubber mold used for molding a tire molding mold was molded using the molded product manufacturing apparatus shown in FIG. Synthetic wood was used as the prototype 1, a shape corresponding to the tread surface of the tire was formed on the surface, and a prototype blade made of stainless steel corresponding to a plurality of sipes was attached. As the backing member 2, a non-foamed gypsum was used and a mold surface was formed on one side. A known polysulfide material was used as the rubber material. The communication path was formed to have a width of 20 mm and a height of 8 mm, and the forward tilt angle of the mold was set to 15 degrees. The liquid rubber material is mixed with the main material and curing agent, stirred for 2 minutes, then defoamed for about 2 minutes in a vacuum chamber (0.005-0.01 MPa), returned to atmospheric pressure, and calmed for about 1 minute. What was made into was used.

  After a required amount of the rubber material was poured into the bowl-shaped container and allowed to stay for about 5 minutes, the opening / closing member was moved upward to allow the rubber material to flow into the molding space from the communication path and be filled. Thereafter, the filled rubber material was cured and removed from the mold to form a rubber mold for molding. The obtained rubber mold for mold removal was free from defects due to air bubbles and air pockets, and no rubber burrs were generated at locations corresponding to the periphery of the original blade. The shape transfer to the rubber mold for molding was also accurately formed, and a high quality rubber mold for molding was able to be obtained.

  For comparison, a rubber mold for molding was molded by the conventional molding process shown in FIG. After injecting the rubber material on the upper surface of the original mold, the vacuum degassing treatment was performed in the same manner as in the example, and the backing member was set to mold the rubber mold for molding, but at the location corresponding to the periphery of the original blade A rubber burr having a thickness of 0.02 mm to 0.05 mm was formed, and it took about 1 hour to remove the rubber burr.

  DESCRIPTION OF SYMBOLS 1 ... Prototype, 2 ... Backing member, 3 ... Frame body, 4 ... Bowl-shaped container, 5 ... Opening / closing member, 6 ... Support stand, 7 ... Support leg part, 10 ... ..Blade for prototype, 20 ... communication path, 21 ... anchor member, 30 ... air vent, 40 ... opening, 41 ... tubular part.

Claims (5)

A method for manufacturing a molded product, in which a liquid material is injected into a molding space in a molding die and filled with gravity to manufacture a molded product,
Setting the communication path connecting the staying portion near the lowermost part of the molding space to a closed state;
Injecting and retaining a required amount of the liquid material in the retention part;
Thereafter, the step of opening the communication path and allowing the liquid material to flow into the molding space by gravity and filling,
The manufacturing method of the molded article which has this. A method for producing a molded article according to claim 1,
Inclining the mold and filling the liquid material so that no air pool is generated between the mold surface of the mold and the liquid surface of the liquid material flowing into the mold;
The manufacturing method of the molded article which has this. In the manufacturing method of the molded article according to claim 1 or 2,
The molded article is a rubber mold for molding, and the liquid material is a rubber material,
The molding die has a shape corresponding to a part of a tread surface of a tire and includes protrusions corresponding to a plurality of sipes formed in the width direction of the tread surface. A mold having a molding space filled with a liquid material formed therein;
A retention part for injecting a required amount of the liquid material and retaining;
A communication path connecting the staying portion near the lowermost part of the molding space;
An apparatus for manufacturing a molded article, comprising: opening and closing means for opening and closing the communication path. An apparatus for manufacturing a molded article according to claim 4,
An apparatus for manufacturing a molded product, comprising tilting means for tilting the mold.

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