JP3791578B2 - Molding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding technique for molding a non-foamed resin molded product such as an elastic part for automobiles, a vibration isolating material, and a cushion material by casting a liquid material.
[0002]
[Prior art]
Conventionally, when molding is performed by casting a highly viscous molding material such as rubber molding, molding with a molding apparatus having a poppet valve inside the mold is possible. That is, when a plasticized molding material is poured into the mold, the poppet valve in the mold is closed by the pressure of the molding material, and the material is trapped in the mold and molded. However, in such a molding apparatus, when the liquid molding material is cast, its viscosity is low.If the casting is not performed at a high speed, the liquid molding material will be in the mold before the pressure for closing the poppet valve rises. Outflow from the meeting surface. Further, in molding with a liquid molding material, if the gas is not sufficiently deaerated by evacuation, bubbles are formed in the molded product, so that it is difficult to perform foamless molding.
[0003]
In particular, in the case where two types of liquid materials are mixed and gelled and non-foamed, such as urethane products, at the laboratory level, the two materials are mixed and stirred uniformly in a vacuumed chamber. It is possible to degas bubbles in the molding material and cast it into a vacuum-drawn mold to perform foamless molding. A major issue is pointed out. Moreover, the liquid molding material for molding urethane or the like generally has a property of curing by reacting with moisture in the air, that is, the liquid molding material adhering to the mold surface or the like is cured. In addition, it is necessary to clean the mold.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and the technical problem is that mass production of non-foamed molded products by casting a low-viscosity liquid molding material is possible, and the apparatus is complicated. The object of the present invention is to provide a molding apparatus that does not need to be cleaned every time it is molded.
[0005]
[Means for Solving the Problems]
As means for effectively solving the above technical problem, a molding apparatus according to the present invention includes a mold unit in which a liquid molding material is cast from a head of a casting machine, and a sprue of the mold unit. A pressurizing / heating unit that clamps and heats the mold while being in contact with a casting nozzle at the tip of the head, and a vacuum chamber that is abutted with the mold unit and connected to a vacuum pump when the mold is clamped. A vacuum case that is defined, and a valve device that is opened at an abutting portion of the mold unit and the vacuum case and opens and closes a vent hole that communicates the vacuum chamber with a casting space of the mold unit. It is. With such a configuration, the inside of the casting space of the mold unit and the inside of the head of the casting machine can be degassed by vacuuming through the vacuum case , and foamless molding can be performed.
[0006]
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an explanatory view showing an embodiment of a molding apparatus according to the present invention , FIG. 2 is an enlarged view of a part of FIG. 1, and (A) shows a mold unit having a casting nozzle and a vacuum case. (B) is explanatory drawing which shows the state which the metal mold unit collided with the casting nozzle and the bottom part of the vacuum case. That is, this molding apparatus is for molding a urethane product having rubber-like elasticity by, for example, mixing a liquid molding material isocyanate (urethane prepolymer + plasticizer) and a polyol and casting the mixture into a mold, As shown in FIG. 1, a mold unit 2 into which the two types of liquid molding materials from the foam casting machine 1 are cast, and a sprue (described later) of the mold unit 2 is used as the foam casting. And a pressurizing / heating unit 3 for clamping and heating in a state of being brought into contact with a casting nozzle (described later) of the machine 1 .
[0008]
The foaming casting machine 1 has a known structure including a degassing device and an internal cleaning mechanism (not shown) for degassing a material piping system and a material tank by a vacuum pump, The high-pressure head 11 is fixedly installed on the top plate 13a. A casting nozzle 12 protruding from the tip (lower end) of the high-pressure head 11 penetrates the top plate 13a downward.
[0009]
The mold unit 2 includes a moving plate 21, a lower mold 22, a middle mold 23, an upper mold 24, and an I mold 25 arranged in a state of being sequentially stacked thereon. Among these, the uppermost I-type 25 is formed with a sprue 2a which is a connection portion with the casting nozzle 12 of the foaming casting machine 1, and the I-type 25 and the upper mold 24 arranged below it are opposed to each other. A runner 2b extending continuously from the sprue 2a is formed between the mating surfaces, and a plurality of molding cavities are formed across the upper mold 24, the middle mold 23, and the lower mold 22 through the runner 2b. A cavity 2c is formed. A material escape portion 2d is formed at the end of the runner 2b .
[0010]
As shown in FIG. 2, the outer peripheral portions of the abutting surfaces (parting surfaces) of the molds 22 to 25 in the mold unit mold unit 2 are sealed through an O-ring 26 in the illustrated combination state. The The abutment surface between the sprue 2a and the casting nozzle 12 is sealed through an O-ring 27.
[0011]
The pressurizing / heating unit 3 has a pressurizing cylinder 31 with an output rod 31a protruding vertically upward, and a central portion attached to the upper end of the output rod 31a via a floating joint 31b by a spherical washer (not shown). A pressure plate 31 (output rod) includes a heat insulating plate 32, a heat plate 33 mounted on the heat insulating plate 32 and incorporating a heater (not shown), and a protective plate 34 mounted on the heat plate 33. By the driving of 31a), the heat insulating plate 32, the heat plate 33 and the protective plate 34 are moved up and down integrally. The mold unit 2 is positioned and set on the protective plate 34 from the outside of the apparatus by a mold loading / unloading mechanism (not shown).
[0012]
The pressurizing / heating unit 3 includes a guide plate 35 fixed to the upper end portion of the cylinder body in the pressurizing cylinder 31 and a vertical reciprocating motion through a plurality of locations on the outer periphery of the guide plate 35 via bearings 35a. The guide rods 36 are freely inserted, and the upper ends of the guide rods 36 are fixed to the outer peripheral portion of the heat insulating plate 32 via flanges 36a. This guides the up-and-down movement of the heat insulating plate 32, the heat plate 33, and the protective plate 34, and prevents rotation.
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
A vacuum case 7 is hermetically attached to the lower surface of the top plate 13a of the mounting base 13 in the foaming casting machine 1 via an O-ring 71. The vacuum chamber VS defined by the vacuum case 7 is The vacuum pump 5 is connected to the suction port of the vacuum pump 5 through a vacuum pipe 51 that is attached through the top plate 13a of the mounting base 13. Further, the upper surface outer peripheral portion of the uppermost I-type 25 in the mold unit 2 is a height (upper limit of movement) at which the sprue 2a abuts on the casting nozzle 12 of the foaming casting machine 1 by the pressurizing / heating unit 3. When raised to a height), it is brought into contact with the bottom of the vacuum case 7.
[0032]
A vent hole 7a is opened at the bottom of the vacuum case 7 at the abutting position with the I-type 25. The I-type 25 communicates with the runner 2b in the mold unit 2 and has a valve seat 25a '. 25a is opened corresponding to the vent hole 7a. Further, a poppet valve 8 having a vertical axis is inserted into the top plate 13a of the mounting base 13 of the foaming casting machine 1 from the outside concentrically with the vent hole 7a. The poppet valve 8 is reciprocally moved in the axial direction (vertical direction) by an external actuator (not shown) . As shown in a partially enlarged view in FIG. The surface 8a enters the vent hole 25a of the I-type 25 located at the movement upper limit height from the vent hole 7a and closes the valve seat 25a 'in close contact therewith.
[0033]
The insertion portion of the poppet valve 8 in the top plate 13 a of the mount 13 is sealed by the O-ring 14, and the insertion portion of the vacuum pipe 51 is sealed by the O-ring 15. Further, a gap formed on the outer periphery between the vent holes 7 a and 25 a when the upper surface of the I-type 25 abuts against the bottom of the vacuum case 7 is sealed by the O-ring 28.
[0034]
On the lower surface of the top plate 13 a of the mounting base 13, a required number of stopper blocks 9 are arranged on the outer periphery of the casting nozzle 12. The stopper block 9 has the same height as the vacuum case 7 and is supported by a bolt 91 screwed into the top plate 13a from below so as to be movable up and down by a predetermined distance and a coil spring 92. It is elastically biased downward by. Therefore, as shown in FIG. 2A, when the mold unit 2 is located at a position away from the casting nozzle 12, the stopper block 9 protrudes downward from the lower surface of the vacuum case 7. It is in.
[0035]
According to the molding apparatus of the second embodiment, the molding operation is performed as follows. First, in the pressurizing / heating unit 3, the heat insulating plate 32, the hot platen 33, and the protective plate 34 are lowered to the movement lower limit position by the pressurizing cylinder 31. The mold unit 2 including the movable plate 21, the lower mold 22, the middle mold 23, the upper mold 24, and the I mold 25 is combined in a state where the mold unit 2 is vertically stacked on the outside of the molding apparatus. It is set on the protective plate 34 by the mechanism.
[0036]
At this time, the protection plate 34 and the mold unit 2 are positioned with respect to each other via a rocket pin or the like (not shown). The molds 22 to 25 of the set mold unit 2 are always heated by the heating plate 33 of the pressurizing / heating unit 3 via the protective plate 34 and the moving plate 21, and the molding material undergoes a thermosetting reaction. Is maintained at an appropriate temperature required for the operation.
[0037]
Next, the mold unit 2 is moved upward by driving the pressurizing cylinder 31 in the pressurizing / heating unit 3 so that the output rod 31a protrudes vertically upward by applying hydraulic pressure. Then, as shown in FIG. 1 , this ascending operation causes the sprue 2 a on the upper surface of the I-type 25 in the mold unit 2 to closely contact the lower end of the casting nozzle 12 of the foaming casting machine 1 via the O-ring 27. At the same time, the outer periphery of the upper surface of the I-type 25 is stopped when it comes into close contact with the bottom of the vacuum case 7 via the O-ring 28.
[0038]
In the above-described mold ascending process, the lower surface of the stopper block 9 that protrudes downward from the lower surface of the vacuum case 7 as shown in FIG. The stopper block 9 ascends together with the mold unit 2 while compressing the coil spring 92 after contacting the upper surface of the I mold 25. The sprue 2a is in close contact with the lower end of the casting nozzle 12 through the O-ring 27, and the outer peripheral portion of the upper surface of the I-type 25 is in close contact with the bottom of the vacuum case 7 through the O-ring 28. At the same time, the stopper block 9 comes into contact with the lower surface of the top plate 13a of the mount 13 and receives a load from the mold unit 2, so that the load from the pressure cylinder 31 is applied to the sprue 2a, the casting nozzle 12, It is possible to prevent concentration at the abutting part.
[0039]
The mold unit 2 is inserted into the guide plate 35 fixed to the pressurizing cylinder 31 and the outer peripheral portion of the heat insulating plate 32 so as to freely reciprocate in the vertical direction through the bearing 35a. The guide rod 36 is prevented from rotating through the heat insulating plate 32, the heat plate 33 and the protective plate 34, and is positioned on the protective plate 34. For this reason, when the I-type 25 and the vacuum case 7 abut each other, the air holes 7a and 25a are connected to each other. Further, the gap formed between the vent holes 7a and 25a is sealed by the O-ring 28.
[0040]
Next, forced evacuation (evacuation) in the vacuum case 7 is performed by the vacuum pump 5. At this time, as shown in FIG. 1 , the poppet valve 8 is in its upper movement position and is in a state in which the vent holes 7a and 25a are opened, so that the vacuum in the vacuum chamber VS in the vacuum case 7 is caused by the forced exhaust. As the degree increases, the runner 2b, the cavity 2c, and the material escape portion 2d, which are casting spaces in the mold unit 2, are also evacuated through the vacuum chamber VS, and are further in close contact with the sprue 2a. The inside of the high-pressure head 11 of the foaming casting machine 1 in communication with the runner 2b is also evacuated through the abutting casting nozzle 12, and the degree of vacuum increases. Isocyanate, which is a liquid molding material for urethane molding, cures by reacting with water vapor in the air. As described above, the inside of the high-pressure head 11 of the foaming casting machine 1 is evacuated, so that It is possible to effectively prevent the liquid molding material from being cured by water vapor in the high-pressure head 11. In addition, bubbles generated in the molding material are also effectively deaerated.
[0041]
When the inside of the vacuum case 7 reaches a predetermined degree of vacuum, as shown in FIG. 2B , the poppet valve 8 is moved downward by an external actuator not shown, and the lower end taper surface 8a thereof is 7 enters the vent hole 25a of the mold unit 2 through the vent hole 7a, and comes into close contact with the valve seat 25a ′, thereby closing the valve.
[0042]
When the air holes 7 a and 25 a are closed by the poppet valve 8, a predetermined amount of the liquid molding material is cast into the mold unit 2 from the foaming casting machine 1. At this time, the runner 2b, the cavity 2c, and the material escape portion 2d, which are the casting spaces of the mold unit 2, are in a vacuumed state as described above, so that the casting is performed quickly, In addition, bubbles do not enter the liquid molding material. The cast liquid molding material receives heat from the mold unit 2 heated by the hot platen 33 of the pressurizing / heating unit 3 and undergoes a curing reaction over time. And the part which the molding material hardened | cured in the cavity 2c becomes a product.
[0043]
When a predetermined time necessary for curing (molding) the liquid molding material in the mold has elapsed, the pressurizing cylinder 31 of the pressurizing / heating unit 3 is operated in the mold clamping release direction. As a result, the mold unit 2 moves downward, and the sprue 2a of the I-type 25 is separated from the casting nozzle 12 of the foaming casting machine 1. Then, the mold unit 2 lowered to the movement lower limit position is moved to the outside of the molding apparatus by a mold loading / unloading mechanism (not shown), the mold is opened, and the molded product is released.
[0044]
When the series of steps described above is completed, a cleaning operation is performed to remove the molding material that has adhered to the mold unit 2 and hardened. However, since the foaming casting machine 1 includes an internal cleaning mechanism, the cleaning operation is performed. Is only necessary for the mold unit.
[0045]
【The invention's effect】
As is apparent from the above description, according to the molding apparatus of the present invention, the inside of the mold unit and the head of the casting machine are evacuated through the vacuum chamber that is brought into contact with the mold unit during mold clamping. Therefore, it is possible to perform defoaming molding by reliably degassing the bubbles in the molding material. In addition, since the casting machine itself does not need to be provided with a vacuuming mechanism, the apparatus becomes inexpensive, and an effect that the cleaning work after molding only needs to be performed only on the mold unit is realized.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of a molding apparatus according to the present invention.
2 is an enlarged view of a part of FIG . 1. FIG . 2A shows a state where the mold unit is separated from the casting nozzle and the vacuum case, and FIG . 2B shows that the mold unit is the casting nozzle and the vacuum case. It is explanatory drawing which shows the state which collided with the bottom part.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Foaming casting machine 11 High pressure head 12 Casting nozzle 13 Mounting base 14, 15, 26, 27, 28, 71 O-ring 2 Mold unit 2a Spru 2b Runner 2c Cavity 2d Material escape part 21 Moving plate 22 Lower mold 23 Middle type 24 Upper type 25 I type 25a Vent hole 25a 'Valve seat 3 Pressurizing / heating unit 31 Pressurizing cylinder 32 Heat insulating plate 33 Heating plate 34 Protection plate 35 Guide plate 36 Guide rod 5 Vacuum pump
51 Vacuum Piping 7 Vacuum Case 7a Vent 8 Poppet Valve 9 Stopper Block 91 Bolt
92 Coil spring
VS vacuum chamber

Claims (1)

A mold unit (2) in which the liquid molding material from the head (11) of the casting machine (1) is cast;
A pressurizing / heating unit (3) for clamping and heating in a state where the sprue (2a) of the mold unit (2) is brought into contact with the casting nozzle (12) at the tip of the head (11);
A vacuum case (7) in which a vacuum chamber (VS) is formed which is abutted with the mold unit (2) at the time of clamping and connected to a vacuum pump (5);
A vent hole which is opened at the abutting portion between the mold unit (2) and the vacuum case (7) and communicates the vacuum chamber (VS) with the casting spaces (2b to 2d) of the mold unit (2). A valve device (8) for opening and closing (7a, 25a);
A molding apparatus comprising:

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