JP2012000794A - Transfer molding method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer molding method with which a cured resin due to being flowed into a plunger part can be automatically removed.SOLUTION: A cylindrical air-gap part (15) that communicates with a cylindrical small diameter part (4a) of a pot (4) and that has a diameter larger than that of the cylindrical small diameter part (4a) is formed. After molding is completed, the plunger (5) is moved back and forth in the pot (4). When the plunger (5) is moved back and an end part of the plunger is located in the cylindrical air-gap part (15), a compression fluid (19) is blown in and separated, and the plunger (5) is moved forth. Thus, a resin dross (21) is scraped from the plunger (5) by a step part (22) of the cylindrical air-gap (15) and the cylindrical small diameter part (4a) and discharged from a fluid discharge port (8) via grooves (10) formed on the plunger (5) along with the compression fluid.

Description

  The present invention relates to a liquid thermosetting resin transfer molding apparatus.

7A to 7F show the transfer molding process of the liquid thermosetting resin.
In FIG. 7A, the transfer molding apparatus includes a first mold 1 and a second mold 2. A liquid thermosetting resin 32 is supplied to a mold pot 30 controlled to an appropriate temperature using a dispenser 31 or the like. At this time, the plunger 33 is disposed at a retracted position. After the resin supply is completed, the dispenser 33 is moved out of the mold, and in FIG. 7B, the mold is closed and a high pressure is applied to the mold.

  Thereafter, in FIG. 7C, the plunger 33 is advanced and held in the state of FIG. 7D in which a constant pressure is applied to the resin to cure the resin. The plunger 33 has a proper clearance with respect to the pot inner diameter in order to slide in the pot 30.

After the resin curing is completed, in FIG. 7E, the plunger 33 is retracted, the mold is opened, and the molded product 35 is taken out by the hand 34 as shown in FIG.
In this resin molding process, when the plunger 33 is advanced in FIG. 7C to apply a constant pressure to the resin, the liquid resin is not yet cured and is in a low viscosity state. For example, when a two-part silicone resin (such as Shin-Etsu Chemical Co., Ltd. LPS-3412) shown in FIG. 8 is used as a supply resin, the viscosity is reduced when it is supplied to a mold temperature-controlled at 120 ° C. It is close to water at 2 Pa · sec or less.

  As shown in FIG. 9, the supplied resin causes a curing reaction in the cavity 36, but at the timing when the plunger 33 is advanced and a constant pressure is applied to the resin (time: around 10 seconds), the resin almost undergoes the curing reaction. As a result, the resin wraps around between the plunger 33 and the pot 30 and is cured.

  Since the resin that has flowed and cured between the plunger 33 and the pot 30 in this way is compressed, it has a great resistance to sliding of the plunger 33. Further, since the amount of wraparound of the resin increases with each shot, the molding pressure required for each shot increases, the size of the molded product 35 varies, and bubbles due to insufficient pressure are generated in the molded product 35.

In order to prevent the change in the sliding resistance of the plunger due to the surrounding resin, Patent Document 1 shown in FIGS. 10A and 10B has been proposed.
In this Patent Document 1, grooves 36 a and 36 b are provided at the tip of the plunger 33, a packing 37 made of a fluororesin or the like is provided in the groove 36 a, and the flow of the resin that flows between the plunger 33 and the pot 30 is packed into the packing 37. The sliding resistance of the plunger 33 is prevented from changing.

JP 2006-351969 A

However, the density of the resin cured at the upper part of the packing 37 is high, a large sliding resistance is added to the plunger 33, and a large plunger activation force is required at the time of molding.
In addition, there is a problem that the resin that adheres and hardens on the plunger wall surface and the packing surface are heavily worn, and this wear powder is mixed into the molded product.

In addition, frequent replacement of the packing 37 is necessary, and the operation of removing and attaching the plunger 33 with the mold temperature lowered is forced, and long-time maintenance is required.
It is an object of the present invention to provide a transfer molding apparatus that can automatically remove the resin that has flowed into the plunger and hardened to prevent the occurrence of plunger sliding resistance and the mixing of wear powder on the packing surface into the molded product. Objective.

  In the transfer molding method of the present invention, a liquid thermosetting resin is placed in a pot in a cavity constituted by a first mold and a second mold, and the liquid thermosetting resin is pressurized by a plunger and molded. In doing so, inside the pot having a cylindrical small-diameter portion communicating with the cavity and a cylindrical void portion formed in communication with the opposite side of the small-diameter cylindrical portion and having a larger diameter than the small-diameter cylindrical portion, The plunger having a plurality of grooves formed on the outer periphery of the end portion on the cavity side in the longitudinal direction is moved to pressurize the liquid thermosetting resin, and at least one of the plurality of grooves is The resin adhering to the plunger is removed by supplying a compressed fluid from a fluid supply port to the cylindrical gap portion in a state of being located in the cylindrical gap portion, and the resin soot removed from the plunger is For the connection point of the the void portion fluid supply port, and the cavity, characterized in that discharged together with the compressed fluid from a fluid discharge port communicating with the cylindrical gap portion at a position on the opposite side.

  In addition, the transfer molding apparatus of the present invention adds a liquid thermosetting resin arranged in a pot in a cavity constituted by a first mold and a second mold by a plunger that moves inside the pot. In the transfer molding apparatus that presses, the pot has a cylindrical small-diameter portion that communicates with the cavity, and a cylindrical void portion that is formed on the opposite side of the small-diameter cylindrical portion from the cavity and has a larger diameter than the cylindrical small-diameter portion. A plurality of grooves are formed on the outer periphery of the end of the plunger on the cavity side at intervals in the longitudinal direction of the plunger, and at least one of the plurality of grooves is the cylindrical gap. A fluid supply port for supplying a compressed fluid to the cylindrical gap portion, and a connection point between the cylindrical gap portion and the fluid supply port on a side opposite to the cavity. Communicates with the cylindrical cavity portion in location, characterized in that a fluid outlet for discharging the air in the cylindrical air gap.

  According to this configuration, the resin that has flowed into the plunger portion and hardened can be automatically removed to prevent the occurrence of plunger sliding resistance and the mixing of wear powder on the packing surface into the molded product.

Configuration diagram of a liquid thermosetting resin transfer molding apparatus according to an embodiment of the present invention The principal part notch perspective view of the movable side metal mold | die of the embodiment and the enlarged view of the principal part Enlarged perspective view of the piece of the same embodiment Sectional drawing which shows the movement of the plunger after the shaping | molding completion of the embodiment Timing chart of plunger movement and compressed air injection according to the embodiment Process diagram of resin residue removal after completion of molding of the embodiment General liquid thermosetting resin transfer molding process diagram Viscosity data of each temperature of two-part silicone resin Curing data of two-part silicone resin Configuration diagram of conventional example

The liquid thermosetting resin molding method of the present invention will be described based on specific embodiments shown in FIGS.
The liquid thermosetting resin molding die includes a stationary mold 1 as a first mold that is attached to a stationary plate of a mold opening / closing device (not shown), and a second die that is attached to the movable side of the mold opening / closing device. A movable mold 2 is provided. A cavity 3 is formed between the fixed mold 1 and the movable mold 2 as a void for forming a molded product.

  A pot 4 is formed in the cavity 3 of the movable mold 2 to store the supplied resin. A movable plunger 5 is inscribed in the pot 4. The plunger 5 is connected to an air cylinder 6 as a plunger driving unit. By supplying compressed air to the air cylinder 6, the plunger 5 can be moved forward and backward. The pushing pressure of the plunger 5 is adjusted by adjusting the pressure of the compressed air applied to the air cylinder 6.

  The pot 4 having the cylindrical small diameter portion 4a communicating with the cavity 3 is formed with a cylindrical gap portion 15 having a diameter larger than that of the cylindrical small diameter portion 4a in communication with the opposite side of the cylindrical small diameter portion 4a to the cavity 3. .

  A plurality of grooves, here grooves 11a and 11b, are formed on the outer periphery of the distal end portion of the plunger 5 at intervals in the longitudinal direction of the plunger 5, and the plunger 5 is shown in FIG. As shown, at least the second groove 11 b is formed so as to communicate with the cylindrical gap 15 at the retracted position.

  The length of the grooves 11a and 11b in the mold clamping direction is smaller than the length of the difference between the radius of the cylindrical gap 15 and the radius of the cylindrical small diameter portion 4a. Further, the depth of the grooves 11a and 11b in the direction perpendicular to the mold clamping direction is smaller than the length of the difference between the radius of the cylindrical gap portion 15 and the radius of the cylindrical small diameter portion 4a.

  A groove 10 is formed on the outer periphery of the plunger 5 below the groove 11 b formed in the plunger 5. Specifically, the groove 10 has a spiral shape extending about the axis of the plunger 5, and the diameter of the apex of the groove 10 is the tip of the plunger 5 where the grooves 11a and 11b are formed. It is the same diameter as the outer periphery of or substantially the same diameter. The depth between the apex and the bottom of the groove 10 gradually decreases as the distance from the grooves 11 a and 11 b approaches the air cylinder 6.

  The movable mold 2 is composed of first, second, and third blocks 2a, 2b, and 2c in the mold clamping direction. The first block 2a includes a part of the cavity 3 and the pot 4. A cylindrical small diameter portion 4a and a concave portion 2d in which the cylindrical gap portion 15 is formed are formed. A cylindrical gap 15 is formed between the plunger 16 and the piece 16 shown in FIG.

  The piece 16 has a flange portion 17 formed around a through hole through which the plunger 5 is inserted, and a rectifying portion 18 having an outer diameter smaller than that of the flange portion 17. The rectifying unit 18 jets the compressed air 19 supplied from the air supply port 7 as a fluid supply port to the recess 2d of the first block 2a toward a position eccentric from the axis of the plunger 5. In addition, a plurality of fins 9, 9,... That divide the flow path of the compressed fluid from the air supply port 7 toward the circumferential surface of the plunger 5 in the circumferential direction of the plunger 5 are formed.

  The second block 2b is formed with a through hole 20 that communicates with the recess 2d of the first block 2a and through which the plunger 5 is inserted. The diameter of the through hole 20 is the small cylindrical diameter of the first block 2a. It has the same diameter or almost the same diameter as the portion 4a. At the position where the plunger 5 is retracted as shown in FIG. 1, a part of the groove 10 formed on the outer periphery of the plunger 5 is located. The second block 2 b is formed with an air discharge port 8 as a fluid discharge port communicating with the through hole 20.

  A compressed air source 12 is connected to the air supply port 7 as shown in FIG. 1 with respect to the air supply port 7 and the air discharge port 8 of the liquid thermosetting resin molding die thus configured. A suction device 14 is connected to the outlet 8 via a dust collector 13.

  When the movable mold 2 is pressed against the fixed mold 1 to close the mold to form a molded product, the plunger 5 is moved inside the pot 4 to pressurize the liquid thermosetting resin. After completion of the molding in the cavity 3, the air supply port of the air cylinder 6 is switched while the air is flowing from the air supply port 7 to the cylindrical gap 15 as shown in the timing chart of FIG. As shown in FIG. 4, the plunger 5 is moved forward and backward at least once in the state in which the plunger 5 is retracted and in the state in which the plunger 5 is advanced as shown in FIG.

The state of the resin adhering to the plunger 5 is shown in FIGS.
At the time of molding, the resin fills the first groove 11a at the tip of the plunger 5, the resin internal pressure in the groove 11a increases, the plunger 5 is aligned, and the gap between the plunger 5 and the pot 4 Becomes uniform. Since the flow rate when the viscous fluid flows through the gap is proportional to the square of the thickness of the gap, the amount of the resin flowing into the side surface of the plunger 5 is 1/5 when the gap is uniform. It will be about 4.

  Further, the second and subsequent grooves 11b are provided. When this groove is not present, the length of the resin flowing into the slight gap between the first block 2a and the plunger 5 from the starting end of the sliding portion between the first block 2a and the plunger 5 is Although it becomes long, the second and subsequent grooves 11b are provided as in this embodiment, so that the volume of the gap between the first block 2a and the plunger 5 is reduced to the first block when there is no groove. Since the volume of the gap between 2a and the plunger 5 can be several hundred times larger, the length of the resin flowing from the start end of the sliding portion between the first block 2a and the plunger 5 can be extremely shortened.

  Although depending on conditions such as material and temperature, in the present embodiment, resin adheres to the first groove 11a and the second groove 11b of the plunger 5, and the resin ridges in the grooves 11a and 11b. 21 are connected as shown in FIG.

  After completion of the molding, the plunger 5 is placed at a position where the first groove of the plunger 5 is fitted into the small cylindrical portion 4a having a small inner diameter of the pot as shown in FIG. The plunger 5 is retracted in the mold opening direction so that the main groove 11b is exposed to the cylindrical gap 15.

  In this arrangement, the resin that has been compressed in the state in which the groove 11b has been fitted into the cylindrical small diameter portion 4a is retracted, and the groove 11b is exposed to the cylindrical gap portion 15 by retreating the plunger 5. The resin compressed in 11b is released, and the outer diameter of the annular resin attached to the groove 11b is wider than the inner diameter of the cylindrical small diameter portion 4a.

  Next, as shown in FIGS. 6 (c) to 6 (d), when the plunger 5 moves forward in the pot 4 in the mold clamping direction, due to the difference in diameter between the cylindrical gap 15 and the small cylindrical diameter 4a. The resin rod 21 is caught by the generated step portion 22, and the resin rod 21 attached to the grooves 11a and 11b is separated between the grooves 11a and 11b. This phenomenon also occurs in the second and subsequent grooves when there are three or more grooves at the tip of the pot 4, and the resin adhering to the plurality of grooves at the tip of the pot 4 is between the grooves. To be separated.

  The resin thus divided adheres to the step portion 22 and the groove 11b, and at the timing when the plunger 5 is retracted, as shown in FIG. 7 is peeled off by flowing compressed air, and is flowed together with the compressed air, flows through the groove 10, is conveyed from the air discharge port 8 to the dust collecting device 13, and is captured by the suction device 14.

  The length in the mold clamping direction between adjacent groove portions of the plunger inscribed in the pot 4 is the length of the two-step cylindrical step portion of the pot 4 (difference between the radius of the cylindrical gap portion 15 and the radius of the small cylindrical portion). If this is the case, the length of the divided resin is the length of the two-stage cylindrical step 22 of the pot 4 provided in the air supply port 7 (the inner diameter of the cylindrical gap 15 and the smaller diameter of the cylinder). 4), the possibility of clogging with resin occurs in the groove at the end of the cylindrical gap 15 in the mold opening direction. The length in the mold clamping direction between the grooves 11a and 11b is preferably shorter than the length of the cylindrical gap 15 in the mold clamping direction.

  Similarly, if the depth of the grooves 11a and 11b is equal to or greater than the amount of the two-step cylindrical step portion of the pot 4 (difference between the radius of the cylindrical gap portion 15 and the radius of the cylindrical small-diameter portion), it is divided. The length of the resin thus made becomes longer than the gap between the cylindrical gap provided in the air supply port and the plunger surface, and there is a possibility that this cylindrical gap 15 will be clogged with resin. For this reason, it is desirable that the depth of the groove portion 11 be equal to or less than the amount of the step portion 22.

  Further, the compressed air is ejected from the air supply port 7 toward the position eccentric from the axial center of the plunger 5 by 1/3 or more of the radius of the plunger 5, thereby being supplied around the cylindrical gap 15. The air rotates around the plunger 5.

  Thereby, a vortex | eddy_current generate | occur | produces around the plunger 5, the flow rate of air increases, and resin adhering to the plunger 5 becomes easy to peel. The direction of the air discharge port 8 is preferably separated from the air supply port 7 by 1/3 or more of the radius of the plunger 5 in the opposite direction to the air supply port 7 in order to make the air flow smooth.

  A compressed air source 12 is connected to the air supply port 7, and a dust collector 13 for collecting resin waste is connected to the air discharge port 8. When the suction device 14 is connected to the tip of the dust collector 13, the pressure difference between the air supply port 7 and the air discharge port 8 increases, the air flow rate increases, and the resin residue peeling performance increases. When the supply pressure of the compressed air is sufficiently high and the distance between the dust collector 13 and the mold is short, the suction device 14 may be omitted. If the suction force of the suction device 14 is sufficiently large, the compressed air source 12 may not be connected to the air supply port 7 and may be opened to the atmosphere.

  Further, as described above, the compressed air from the air supply port 7 is sprayed to the plunger 5 from between the fins 9 formed in the piece 16, so that the air flowing around the plunger 5 is uniformly turned and high speed is achieved. It becomes possible to flow in.

  Further, by providing the spiral groove 10 at the rear of the air supply position, that is, behind the grooves 11a and 11b as described above, it is possible to further increase the rotational force of the air, and at the end of the air flow path. A decrease in air flow rate can be prevented. By gradually decreasing the groove depth of the groove 10 in the direction from the air supply port 7 toward the air discharge port 8, the air flow path area becomes narrower, and the decrease in the air flow rate at the end of the air flow path can be further suppressed.

  In order to analyze the effect of increasing the flow velocity of the air flowing around the plunger 5 in the embodiment product by the fin 9 and the spiral groove 10, the plunger 5 in the following comparison product 1 and comparison product 2 is compared for comparison. We observed the flow of air flowing around.

-Implement product Model with fin 9 + spiral groove 10-Comparison product 1
No fins 9 (injected compressed air toward the center of the plunger 5)
+ Model with spiral groove 10 ・ Comparative product 2
Fin 9 is provided. + When the shape of the groove 10 is not a spiral shape As a result, the flow velocity of the air flowing around the plunger 5 is increased by the fin 9 and the spiral groove 10, respectively, and adheres to the plunger 5 and the pot 4. It was found that the ability to peel off the resin residue has increased.

  In addition, although the best result was confirmed when the shape of the groove 10 is a spiral shape, the plunger 5 is arranged so that a straight groove that is not spiraled follows the direction in which the air supply port 7 and the air discharge port 8 are arranged. Even when it was formed on the peripheral surface, a good flow of the peeled resin soot and air was confirmed as compared with the case where the groove 10 was not formed.

Moreover, although compressed air was used as compressed fluid in said embodiment, various inert gas, such as N2, can also be used as compressed fluid.
In the above embodiment, the case of a transfer molding apparatus for a liquid thermosetting resin has been described as an example. However, a tablet-shaped resin is supplied to the pot 4, the tablet-shaped resin is melted, and a molten resin is supplied. It can be similarly applied to transfer molding in which is pushed into the cavity 3 by the plunger 5.

  The present invention contributes to improving the performance of various resin moldings in which a liquid thermosetting resin is pressed into a cavity by a plunger.

1 Fixed mold (first mold)
2 Movable side mold (second mold)
2a, 2b, 2c 1st, 2nd, 3rd block 2d Recess of block 2a 3 Cavity 4 Pot 5 Plunger 6 Air cylinder 7 Air supply port (fluid supply port)
8 Air outlet (fluid outlet)
DESCRIPTION OF SYMBOLS 9 Fin 10 Spiral-shaped groove | channels 11a and 11b Groove 12 of the front-end | tip part of the plunger 5 Compressed air source 13 Dust collector 14 Suction device 15 Cylindrical space | gap part 16 Piece 17 Gutter part 18 Rectification part 19 Compressed air (compressed fluid)
20 Through-hole 21 Resin 22 Step

Claims (10)

When the liquid thermosetting resin is placed in the pot in the cavity constituted by the first mold and the second mold, and the liquid thermosetting resin is pressurized with a plunger and molded,
A cylindrical small-diameter portion that communicates with the cavity, and a side of the cavity inside the pot that is formed in communication with the opposite side of the cylindrical small-diameter portion to the cavity and has a larger cylindrical gap than the small-diameter cylindrical portion. And pressurizing the liquid thermosetting resin by moving the plunger formed with a plurality of grooves at intervals in the longitudinal direction on the outer periphery of the end of
In a state where at least one of the plurality of grooves is located in the cylindrical gap, a compressed fluid is supplied from a fluid supply port to the cylindrical gap to remove the resin adhering to the plunger,
The resin soot removed from the plunger, together with the compressed fluid from the fluid discharge port communicating with the cylindrical gap at a position opposite to the cavity with respect to the connection point between the cylindrical gap and the fluid supply port Transfer molding method to discharge. In a transfer molding apparatus that pressurizes a liquid thermosetting resin disposed in a pot in a cavity constituted by a first mold and a second mold with a plunger that moves inside the pot,
The pot is
A cylindrical small diameter portion communicating with the cavity;
The cylindrical small-diameter portion is formed in communication with the opposite side of the cavity and has a cylindrical void portion having a larger diameter than the cylindrical small-diameter portion,
A plurality of grooves are formed on the outer periphery of the end of the plunger on the cavity side at intervals in the longitudinal direction of the plunger,
In a state where at least one of the plurality of grooves is located in the cylindrical gap, a fluid supply port for supplying a compressed fluid to the cylindrical gap is provided,
Transfer molding provided with a fluid discharge port that communicates with the cylindrical gap portion at a position opposite to the cavity with respect to a connection portion between the cylindrical gap portion and the fluid supply port, and discharges air in the cylindrical gap portion. apparatus. The transfer molding apparatus according to claim 2, further comprising a groove formed on an outer periphery of the plunger from the end where the plurality of grooves are formed toward the other end and communicated with the cylindrical gap. The transfer molding apparatus according to claim 3, wherein the groove has a spiral shape extending about an axis of the plunger. The transfer molding apparatus according to claim 4, wherein the depth of the spiral groove gradually decreases in a direction from the fluid supply port to the fluid discharge port. The transfer molding apparatus according to claim 2, wherein a length in a mold clamping direction between adjacent grooves of the plurality of grooves is smaller than a length of a difference between a radius of the cylindrical gap portion and a radius of the cylindrical small diameter portion. The transfer molding apparatus according to claim 2, wherein a depth of the plurality of grooves in a direction perpendicular to the mold clamping direction is smaller than a length of a difference between a radius of the cylindrical gap portion and a radius of the cylindrical small diameter portion. The transfer molding apparatus according to claim 4, wherein the fluid supply port is disposed so as to eject a compressed fluid toward a position eccentric from an axis of the plunger. The fin which divides | segments the flow path of the compressed fluid which goes to the surrounding surface of the said plunger from the said fluid supply port to the surrounding surface of the said plunger between the said fluid supply port and the said cylindrical space | gap part is arrange | positioned. Transfer molding equipment. The transfer molding apparatus according to claim 2, wherein a dust collector is disposed at an air discharge destination of the fluid discharge port.

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