JPWO2018139664A1 - Injection molding method and injection molding apparatus - Google Patents

Abstract

A heat medium passage (30) and a refrigerant passage (32) are formed in the movable core (14) which is a mold. The heat medium passage (30) and the refrigerant passage (32) are supplied from the heating temperature controller (34) via the heat medium supply line (36), and the refrigerant is supplied from the cooling temperature controller (38). The cooling medium supplied through the supply line (40) circulates. Further, each of the heat medium supply line (36) and the refrigerant supply line (40) includes a heat medium circulation line (54) for returning the heating medium to the heating temperature controller (34), and a cooling medium for cooling the cooling medium. A refrigerant circulation line (62) for returning to the adjuster (38) is connected.

Description

  The present invention relates to an injection molding method and an injection molding apparatus for obtaining a resin molded product by cooling and curing a molten resin material injected into a cavity formed by a mold.

  Injection molding is well known as a technique for obtaining a resin molded product from a molten resin material. In this case, the molten resin material is injected into a cavity formed by a mold. As a result, the molten resin material is deformed into a shape corresponding to the shape of the cavity, and in this state, it is cooled and cured in the cavity. Thereafter, mold opening is performed, and a resin molded product having a shape corresponding to the shape of the cavity is taken out.

  When it is necessary to change the temperature depending on the molding site, a relatively high temperature site and a relatively low temperature site are formed on the mold, in other words, a temperature difference is provided. For example, in the prior art described in JP-A-7-68614, a heating medium passage and a refrigerant passage are provided in a mold, and heating oil (heating medium) is circulated through the heating medium passage in a molding site where high temperature is required. Cooling water (cooling medium) is circulated through the coolant passage in the molding site where low temperature is required.

  In order to mass-produce resin molded products on an industrial scale, reduction of tact time is required. For this purpose, for example, it is conceived that the cooling medium is circulated through the refrigerant passage also during the cooling and hardening, thereby increasing the cooling and hardening speed of the molten resin material.

  However, in the prior art described in Japanese Patent Application Laid-Open No. 7-68614, a molding part that requires a high temperature (a region in which a heat medium passage is formed) and a molding part that requires a low temperature (a region in which a refrigerant passage is formed) are provided. Partitioning with heat insulating material prevents both areas from being affected. Therefore, it is difficult to increase the cooling rate in the region where the heat medium passage is formed even if the cooling medium is circulated during the cooling and curing. As described above, the conventional technique has a problem that it is not easy to shorten the tact time.

  A main object of the present invention is to provide an injection molding method in which it is easy to increase the cooling rate of a molten resin material.

  Another object of the present invention is to provide an injection molding apparatus capable of shortening tact time.

According to one embodiment of the present invention, in an injection molding method for injecting a molten resin material and cooling and curing to obtain a resin molded product,
A cavity forming step of forming a cavity using a mold provided with a heat medium passage for circulating a heating medium for heating the molten resin material and a refrigerant passage for circulating a cooling medium for cooling the molten resin material;
An injection process in which the temperature is adjusted by a heating temperature controller and the molten resin material is supplied to the cavity while circulating the heating medium supplied through the heating medium supply line to the heating medium passage;
After the injection is completed, the communication between the heating medium supply line and the heating medium passage is cut off, and the heating medium is sealed in the heating medium passage, while the heating medium supply line is connected from the heating temperature controller. The heating medium supplied to the heating medium is returned to the heating temperature controller via a heating medium circulation line provided in the heating medium supply line, and the cooling medium whose temperature is adjusted by the cooling temperature controller is adjusted. A cooling step of circulating the refrigerant passage to cool the molten resin material in the cavity;
A blow step of stopping the flow of the cooling medium in the refrigerant passage after the cooling is completed and blowing the cooling medium in the refrigerant passage with a blow fluid;
An injection molding method is provided.

  That is, in the present invention, since the molten resin material in the cavity is heated by circulating the heating medium in the heat medium passage during the injection process, until the filling of the molten resin material into the cavity is completed. The molten resin material maintains fluidity. For this reason, it is prevented that the molten resin material loses fluidity during the injection process, and that an unfilled portion is formed in the cavity due to this.

  On the other hand, in the cooling process, a cooling medium is circulated through the refrigerant passage to cool the molten resin material in the cavity. Thereby, the cooling rate of a molten resin material becomes large. For this reason, the time (tact time) from injecting the molten resin material to obtaining the resin molded product is shortened. Accordingly, it is possible to efficiently produce a resin molded product, and it is easy to achieve mass production on an industrial scale.

  In addition, during the cooling process, the heating medium is returned to the heating temperature controller to keep the heating medium at a predetermined temperature. Therefore, when performing the injection process in the next injection molding, the heating medium that has already reached a sufficient temperature can be supplied to the mold. Further, as the heating medium is resupplied to the heating medium supply line, the heating medium immediately circulates in the heating medium passage. As described above, since the temperature of the mold rises quickly, the time from the mold opening to the injection process can be shortened.

  In addition, during the cooling step, a heating medium is enclosed in the heat medium passage. That is, in this case, the heating medium is not discharged from the heat medium passage after the injection process is finished. For this reason, since it can transfer to a cooling process from an injection process quickly, it is possible to aim at the further shortening of the tact time which injection molding requires. In addition, since the cooling capacity of the cooling medium is larger than the heating capacity of the heating medium, the temperature of the mold is sufficiently lowered during the cooling process even when the heating medium is sealed in the heat medium passage. be able to.

  Further, the cooling medium is blown with a blowing fluid before the heating medium is resupplied to the mold. For this reason, since the cooling medium is discharged from the refrigerant passage, it is avoided that when the heating medium is supplied again, the cooling medium reaches the boiling point and steam is generated.

  During the injection process, the cooling medium is preferably returned to the cooling temperature controller through a refrigerant circulation line provided in a refrigerant supply line that supplies the cooling medium from the cooling temperature controller to the refrigerant passage. Thereby, the state in which the temperature of the cooling medium is sufficiently lowered is maintained. Accordingly, when performing the cooling step, the cooling medium maintained at a predetermined temperature can be quickly supplied to the mold. That is, it is possible to immediately switch from the injection process to the cooling process, and to sufficiently increase the cooling rate of the molten resin material.

  During the blowing process, it is preferable to return the cooling medium to the cooling temperature controller via the refrigerant circulation line for the same reason as described above.

  Preferable examples of the heating medium and the cooling medium include oil and water, respectively. In this case, even when the oil is sealed in the heating medium as described above, the temperature of the mold can be sufficiently lowered by circulating water through the refrigerant passage.

Further, according to another embodiment of the present invention, in an injection molding apparatus for injecting a molten resin material and cooling and curing to obtain a resin molded product,
A cavity for supplying the molten resin material is formed, and a heat medium passage for circulating a heating medium for heating the molten resin material and a refrigerant passage for circulating a cooling medium for cooling the molten resin material are provided. Mold and
A heating temperature controller for controlling the temperature of the heating medium;
A heating medium supply line for supplying the heating medium from the heating temperature controller to the heating medium passage;
A heating medium circulation line for branching from the heating medium supply line and returning the heating medium to the heating temperature controller;
A switching valve for selectively setting the heat medium supply line in a communication state or a communication cut-off state with respect to the heat medium passage or the heat medium circulation line;
A cooling temperature controller for controlling the temperature of the cooling medium;
A refrigerant supply line for supplying the cooling medium from the cooling temperature controller to the refrigerant passage;
The state is switched from the state where the heating medium flows through the heat medium passage to the state where the cooling medium flows through the refrigerant passage, and from the state where the cooling medium flows through the refrigerant passage, the heating medium passes through the heat medium passage. A control unit for switching to a state in which
A blow fluid supply source for supplying a blow fluid for blowing the cooling medium in the refrigerant passage;
An injection molding apparatus is provided.

  By configuring in this way, the heating medium is circulated in the heat medium passage to heat the molten resin material in the cavity, or the cooling medium is circulated in the refrigerant passage to cool the molten resin material in the cavity. Further, during this cooling, the heating medium is sealed in the heating medium passage, while the heating medium supplied from the heating temperature controller to the heating medium supply line is returned to the heating temperature controller to bring the heating medium to a predetermined temperature. It becomes possible to keep. Therefore, it is possible to prevent the molten resin material from losing its fluidity during injection or to prevent the formation of an unfilled portion in the cavity, and the resin molding after injecting the molten resin material. The tact time until the product is obtained can be shortened, and further, the time from the mold opening to the injection process can be shortened.

  In addition, the control unit supplies the blow fluid when the state is changed from the state in which the cooling medium flows through the refrigerant passage to the state in which the heating medium flows through the heat medium passage. As a result, the cooling medium is discharged from the refrigerant passage, so that it is avoided that the cooling medium reaches the boiling point in the mold during the supply of the heating medium and steam is generated.

  The injection molding apparatus is preferably provided with a refrigerant circulation line that branches from the refrigerant supply line and returns the cooling medium to the cooling temperature controller. This facilitates keeping the cooling medium at a predetermined temperature. Therefore, when the cooling medium is necessary, it is possible to quickly supply the cooling medium whose temperature has been sufficiently lowered. In this case, a switching valve may be provided in order for the refrigerant supply line to be selectively connected to or disconnected from the refrigerant passage or the refrigerant circulation line.

  The cooling medium may be returned to the cooling temperature controller via the refrigerant supply line and the refrigerant circulation line when the heating medium flows through the heat medium passage. Thereby, it is avoided that the cooling medium receives the heat from the heating medium and reaches the boiling point, or is vaporized to become a vapor.

  For the same reason, when the cooling medium in the refrigerant passage is blown by the blow fluid, it is preferable to return the cooling medium to the cooling temperature controller via the refrigerant supply line and the refrigerant circulation line. In the above, preferred examples of the heating medium and the cooling medium include oil and water as described above.

  According to the present invention, the heating medium passage and the refrigerant passage are provided in the mold, and when the fluidity of the molten resin material is ensured, the heating medium is circulated through the heating medium passage, while the molten resin material filled in the cavity is cooled and cured. When the cooling medium is used, a cooling medium is circulated through the refrigerant passage. For this reason, it is possible to prevent the molten resin material from losing its fluidity during injection or to prevent the formation of an unfilled portion in the cavity, and the resin after the molten resin material is injected. It is possible to shorten the tact time until a molded product is obtained.

  In addition, when the cooling medium is circulated through the refrigerant passage, the heating medium is returned to the heating temperature controller. For this reason, since the heating medium can be maintained at a predetermined temperature, it is possible to shorten the time from the mold opening to the injection process.

It is a principal part schematic longitudinal cross-sectional view of the injection molding apparatus which concerns on embodiment of this invention. FIG. 2 is a schematic diagram showing a flow path of a heating medium and a cooling medium when performing a cavity forming step and an injection step in the injection molding apparatus of FIG. 1. FIG. 2 is a schematic diagram illustrating a heating medium and a cooling medium flow path when performing a cooling step in the injection molding apparatus of FIG. 1. FIG. 2 is a schematic view showing a flow path of a heating medium and a cooling medium when performing a blowing process in the injection molding apparatus of FIG. 1.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an injection molding method according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to an injection molding apparatus for carrying out the method.

  FIG. 1 is a schematic vertical sectional view of an essential part of an injection molding apparatus 10 according to the present embodiment. The injection molding apparatus 10 includes a convex mold 12, a movable core 14, and a concave mold 16. The convex mold 12 is a fixed mold, and both the movable core 14 and the concave mold 16 are movable molds that can be displaced so as to approach or separate from the convex mold 12.

  The convex mold 12 is provided on a fixed platen 18 that is positioned and fixed to the work station, and has a convex portion 20 that protrudes toward the movable core 14. On the other hand, the concave mold 16 is formed with a concave section 24 that is recessed from the convex mold 12 side toward the movable platen 22 side. The movable platen 22 is displaced in a direction approaching or separating from the convex mold 12 under the action of a displacement mechanism (for example, a hydraulic cylinder or the like) not shown. Following this, the concave mold 16 is also displaced in the same direction.

  The movable core 14 interposed between the convex mold 12 and the concave mold 16 can be displaced, for example, in a direction perpendicular to the paper surface of FIG. 1 under the action of a displacement mechanism such as a hydraulic cylinder (not shown). The movable core 14 has a shape corresponding to the concave portion 24, and the convex portion 20 enters below the movable core 14 that has entered the concave portion 24. Thereby, the cavity 26 is formed.

  In the movable core 14, a heat medium passage 30 is formed at a portion close to the cavity 26, and a refrigerant passage 32 is formed at a portion facing the recess 24 so as to be close to the heat medium passage 30. . Both the heat medium passage 30 and the refrigerant passage 32 extend along a direction orthogonal to the paper surface of FIG.

  A heating temperature controller 34 (heating temperature controller) for supplying heating oil as a heating medium is connected to the heating medium passage 30 via a heating medium supply line 36. On the other hand, a cooling temperature controller 38 (cooling temperature controller) for supplying cooling water as a cooling medium is connected to the refrigerant passage 32 via a refrigerant supply line 40. The heating temperature controller 34 and the cooling temperature controller 38 are electrically connected to a control circuit 44 (control unit) via signal lines 42a and 42b, respectively. The control circuit 44 controls the heating temperature controller 34 and the cooling temperature controller 38 via the signal lines 42a and 42b to adjust the temperature of the heating oil and the cooling water.

  As shown in detail in FIG. 2, a return line 46 is also provided between the heating temperature controller 34 and the heat medium passage 30. That is, the heating oil supplied from the heating temperature controller 34 to the heating medium passage 30 through the heating medium supply line 36 passes through the heating medium passage 30 and then passes through the return line 46 to be the heating temperature controller. Return to 34.

  Further, the heat medium supply line 36 is provided with a first three-way valve 50 as a switching valve, and a direction changing line 52 from the first three-way valve 50 toward the return line 46. The direction change line 52 and the downstream side of the return line 46 constitute a heat medium circulation line 54 that returns the heating oil to the heating temperature controller 34 without reaching the heat medium passage 30. For this reason, the heat medium circulation line 54 is branched from the heat medium supply line 36.

  The first three-way valve 50 selectively connects the heat medium supply line 36 to the heat medium passage 30 or the heat medium circulation line 54 while blocking the communication. That is, when the heat medium supply line 36 communicates with the heat medium passage 30, the heat medium supply line 36 and the heat medium circulation line 54 are in a communication cut-off state. On the contrary, when the heat medium supply line 36 communicates with the heat medium circulation line 54, the communication between the heat medium supply line 36 and the heat medium passage 30 is blocked.

  A first on-off valve 56 is provided on the downstream side of the heat medium supply line 36 from the first three-way valve 50. A second opening / closing valve 58 is provided on the upstream side of the return line 46 from the connection point of the direction change line 52.

  On the other hand, the refrigerant supply line 40 is provided with a second three-way valve 60 as a switching valve. The second three-way valve 60 is connected to a refrigerant circulation line 62 that returns the cooling water to the cooling temperature controller 38 without reaching the refrigerant passage 32. That is, the refrigerant circulation line 62 branches from the refrigerant supply line 40.

  The second three-way valve 60 selectively connects the refrigerant supply line 40 to the refrigerant passage 32 or the refrigerant circulation line 62 while blocking the communication. That is, when the refrigerant supply line 40 communicates with the refrigerant passage 32, the communication between the refrigerant supply line 40 and the refrigerant circulation line 62 is blocked. On the contrary, when the refrigerant supply line 40 communicates with the refrigerant circulation line 62, the refrigerant supply line 40 and the refrigerant passage 32 are in a communication cut-off state.

  A third three-way valve 64 is interposed downstream of the second three-way valve 60 in the refrigerant supply line 40. A compressed air source 66 that supplies compressed air is connected to the third three-way valve 64 via an air supply line 68. That is, the air supply line 68 communicates with the refrigerant supply line 40 or is blocked by appropriately setting the opening direction of the third three-way valve 64. The compressed air serves as a blow fluid for blowing cooling water from the refrigerant passage 32. In other words, the compressed air source 66 is a blow fluid supply source.

  The first three-way valve 50, the second three-way valve 60, the third three-way valve 64, the first on-off valve 56, and the second on-off valve 58 are operated under the control action of the control circuit 44. That is, the control circuit 44 sets the opening direction of the first three-way valve 50 to the third three-way valve 64 and sets the first on-off valve 56 and the second on-off valve 58 to an open state or a closed state.

  A drain line 70 is connected to the refrigerant passage 32. The cooling water supplied from the cooling temperature controller 38 to the refrigerant passage 32 through the refrigerant supply line 40 flows through the refrigerant passage 32 and is then discharged to the outside of the concave mold 16 through the drain line 70. The discharged cooling water may be exhausted to a drainage groove or the like, or may be returned to the cooling temperature controller 38.

  In the above configuration, the convex mold 12 is provided with a plurality of injection machines (not shown). The molten resin material 72 injected from each injector passes through a runner, a sprue and a gate (not shown) (not shown) and is supplied to the cavity 26.

  The injection molding apparatus 10 according to the present embodiment is basically configured as described above. Next, the function and effect will be described in relation to the injection molding method according to the present embodiment. .

  Prior to closing the mold, first, heating oil is supplied to the heat medium passage 30 formed in the movable core 14. For this reason, as shown in FIG. 2, the control circuit 44 sets the opening direction of the first three-way valve 50 so that the heating oil flows only in the direction from the heat medium supply line 36 toward the heat medium passage 30, Both the first on-off valve 56 and the second on-off valve 58 are opened. In FIG. 2, an open state (or direction) is indicated by “◯”, and a closed state (or direction) is indicated by “x”, and the same applies to FIGS. 3 and 4.

  Accordingly, the heating oil adjusted to a predetermined temperature by the heating temperature controller 34 passes through the heat medium supply line 36 and flows into the heat medium passage 30. As a result, the movable core 14 rises to a predetermined temperature. The heating oil flowing through the heat medium passage 30 is returned to the heating temperature controller 34 through the return line 46, and the temperature is adjusted again by the heating temperature controller 34. Thereafter, the heat medium is again supplied to the heat medium passage 30 through the heat medium supply line 36. That is, at this time, the entire amount of heating oil is supplied to the heating medium passage 30 and returns to the heating temperature controller 34 via the return line 46. In other words, the heating oil does not return to the heating temperature controller 34 via the direction change line 52 (heat medium circulation line 54).

  The control circuit 44 operates the second three-way valve 60 and the third three-way valve 64 together. Specifically, the opening direction of the second three-way valve 60 is a direction in which communication between the refrigerant supply line 40 and the refrigerant passage 32 is blocked and the refrigerant supply line 40 and the refrigerant circulation line 62 communicate with each other. For this reason, the entire amount of cooling water returns from the refrigerant supply line 40 to the cooling temperature controller 38 via the refrigerant circulation line 62. Further, the third three-way valve 64 blocks communication between the air supply line 68 and the refrigerant supply line 40.

  Thereafter, a cavity forming step is performed to perform injection molding. Specifically, the concave mold 16 and the movable core 14 are displaced under the action of the displacement mechanism provided on each of the movable platen 22 and the movable core 14 to approach the convex mold 12. As a result, the mold is closed and the cavity 26 is formed. Since the heat medium passage 30 is closer to the cavity 26 than the refrigerant passage 32, the inside of the cavity 26 is easily subjected to the heat of the heating oil, and is therefore likely to rise to an appropriate temperature.

  Next, an injection process is performed. Specifically, the molten resin material 72 is injected from each of the plurality of injection machines. The molten resin material 72 passes through the runner, the sprue and the plurality of gates in this order, and is introduced into the cavity 26. Since the movable core 14 has already risen to an appropriate temperature because the heating oil is supplied, the molten resin material 72 is appropriately heated. For this reason, it is difficult for the molten resin material 72 to harden, and the flowable state is maintained.

  As described above, the cooling water is returned to the cooling temperature controller 38 via the refrigerant circulation line 62. For this reason, cooling water does not exist in the refrigerant passage 32 in the movable core 14. Therefore, it is possible to avoid boiling and evaporating the cooling water in the refrigerant passage 32.

  After the molten resin materials 72 injected from the respective injection machines are associated with each other in the cavity 26, and the cavity 26 is filled with the molten resin material 72 (in other words, the molten resin material 72 is filled in the cavity 26). After), a pressure is applied to the molten resin material 72 from at least one of the plurality of gates.

  In order to apply the pressure, for example, the molten resin material 72 may be injected from the injection machine. In this case, the pressure applying step can be performed also as a so-called pressure holding step of injecting an amount of the molten resin material 72 corresponding to the amount of shrinkage accompanying the curing of the molten resin material 72 in the cavity 26.

  Alternatively, pressure may be applied to the molten resin material 72 by inserting a pin into the gate. Furthermore, the molten resin material 72 in the cavity 26 can be pressed by providing a pressing pin on the concave mold 16 or the convex mold 12 and operating the pressing pin.

  Next, a cooling process for cooling the molten resin material 72 in the cavity 26 is performed. For this reason, the control circuit 44 changes the opening direction of the first three-way valve 50 and the second three-way valve 60. That is, the opening direction of the first three-way valve 50 is set so that the heating oil flows only in the direction from the heat medium supply line 36 to the return line 46 through the direction change line 52, as shown in FIG. . Thereby, the communication between the heat medium supply line 36 and the heat medium passage 30 is blocked, and the heat medium supply line 36 and the heat medium circulation line 54 communicate with each other. Accordingly, the heating oil is returned to the heating temperature controller 34 via the heating medium circulation line 54, and the heating oil that has circulated through the heating medium passage 30 is enclosed in the heating medium passage 30. .

  In addition, the control circuit 44 performs control to close the first on-off valve 56 and the second on-off valve 58. For this reason, the heating oil that has flowed from the first three-way valve 50 to the direction change line 52 is prevented from flowing back from the second on-off valve 58 through the heat medium passage 30 to the heat medium supply line 36.

  The opening direction of the second three-way valve 60 is set so that the cooling medium flows only in the direction from the refrigerant supply line 40 toward the refrigerant passage 32. That is, the refrigerant supply line 40 and the refrigerant passage 32 communicate with each other, and the communication between the refrigerant supply line 40 and the refrigerant circulation line 62 is blocked. Therefore, the entire amount of cooling water is not supplied to the refrigerant passage 32 and returned to the cooling temperature controller 38 via the refrigerant circulation line 62. The third three-way valve 64 maintains communication between the air supply line 68 and the refrigerant supply line 40.

  As the cooling water flows through the refrigerant passage 32, the temperature of the movable core 14 decreases. Accordingly, the heat of the molten resin material 72 is taken by the movable core 14. For this reason, the molten resin material 72 comes to cool at a high cooling rate. As a result of the hardening of the molten resin material 72 by cooling, a resin molded product having a shape substantially corresponding to the shape of the cavity 26 is obtained.

  As described above, in the present embodiment, when the molten resin material 72 is cooled, the cooling water as the cooling medium is supplied into the movable core 14. For this reason, the cooling rate of the molten resin material 72 is increased, and accordingly, the tact time from injection to mold opening (removal of the resin molded product) can be shortened.

  In addition, in this case, since the cooling water is circulated in advance through the refrigerant circulation line 62, the opening temperature of the second three-way valve 60 is changed at a predetermined temperature when the cooling water needs to be supplied. It is possible to immediately circulate the cooling water adjusted to the refrigerant passage 32. This also increases the cooling rate of the molten resin material 72, so that the tact time can be further shortened.

  The cooling water is exhausted to the drainage groove via the drainage line 70. Alternatively, the cooling water may be returned from the drain line 70 to the cooling temperature controller 38. On the other hand, in the heat medium passage 30, the state in which the heating oil is enclosed is maintained. That is, the heating oil is not discharged from the heat medium passage 30 when shifting from the injection process to the cooling process. Accordingly, the injection process can be promptly shifted to the cooling process. In addition, the cooling capacity of the cooling water is larger than the heating capacity of the heating oil. For this reason, the temperature of the movable core 14 is sufficiently lowered during the cooling process.

  After the molten resin material 72 is cured and a resin molded product is obtained, the mold is opened. At this time, the control circuit 44 performs control to change the opening direction of the first three-way valve 50 to the third three-way valve 64 and to open the first on-off valve 56 and the second on-off valve 58. That is, as shown in FIG. 4, the opening direction of the first three-way valve 50 is such that the heat medium supply line 36 and the heat medium passage 30 communicate with each other and the heat medium supply line 36 and the heat medium circulation line 54 communicate with each other. Will be in the direction. Accordingly, the heating oil flows only from the heat medium supply line 36 through the first on-off valve 56 toward the heat medium passage 30. As a result, the heating oil adjusted to an appropriate temperature by the heating temperature controller 34 is circulated and supplied to the heat medium passage 30 as in the injection process.

  That is, in the present embodiment, even when the heating oil is not supplied to the heat medium passage 30, the heating oil is circulated through the heat medium circulation line 54 so as to maintain a predetermined temperature. Therefore, the heating oil adjusted to a predetermined temperature can be immediately supplied to the movable core 14.

  Further, when the heating medium is resupplied to the heating medium supply line 36 from the state where the heating oil is sealed in the heating medium passage 30, the heating oil immediately starts to flow through the heating medium passage 30. That is, the time from the start of resupply until the heating medium starts to flow through the heat medium passage 30 is short. In combination with the above, it is possible to raise the temperature of the movable core 14 at a high speed.

  In addition, in this case, the temperature of the movable core 14 is increased while the mold opening operation is being performed. Therefore, the next injection molding can be performed promptly after the mold opening. Combined with the above, the time from the opening of the mold to the start of the next injection process is shortened.

  On the other hand, the opening direction of the second three-way valve 60 is a direction in which the communication between the refrigerant supply line 40 and the refrigerant passage 32 is cut off and the refrigerant supply line 40 and the refrigerant circulation line 62 communicate with each other as in the injection process. Accordingly, the cooling water flows only in the direction returning to the cooling temperature controller 38 via the refrigerant circulation line 62. Further, the opening direction of the third three-way valve 64 is set to a direction in which the air supply line 68 and the refrigerant supply line 40 communicate with each other. As a result, the cooling water does not flow through the refrigerant supply line 40, but only the compressed air supplied from the compressed air source 66 and passed through the air supply line 68 flows.

  This compressed air pushes the cooling water in the refrigerant supply line 40 and the refrigerant passage 32 to the drain line 70. Thereby, the blow process in which cooling water is blown is performed, and the inside of the refrigerant passage 32 is replaced with compressed air. Since the heating oil is supplied to the heat medium passage 30 in this state, the cooling water remaining in the refrigerant passage 32 is prevented from boiling and vaporizing.

  In this way, the mold opening proceeds while the heating oil is supplied to the heat medium passage 30 and the compressed air is supplied to the refrigerant passage 32 to blow and discharge the cooling water. After the mold opening is completed, the exposed resin molded product is pushed out by an eject pin (not shown) to release the mold. In addition, a blow process may be continued until the mold release of a resin molded product is complete | finished, and may be complete | finished in the middle of mold opening or mold release.

  Thereafter, the cavity forming step is performed again to perform the next injection molding. As described above, since the heating oil has already been supplied to the movable core 14, the movable core 14 has risen to a predetermined temperature. For this reason, it is possible to implement injection molding promptly.

  The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, the mold for forming the heat medium passage 30 and the refrigerant passage 32 is not limited to the movable core 14, and the heat medium passage 30 and the refrigerant passage 32 may be formed in the convex mold 12 or the concave mold 16. However, the heat medium passage 30 and the refrigerant passage 32 may be formed in all of the convex mold 12, the movable core 14, and the concave mold 16. Further, for example, it is possible to provide only the heat medium passage 30 in the convex mold 12 and provide only the refrigerant passage 32 in the movable core 14 or the concave mold 16.

  Further, the injection molding apparatus 10 may be configured without including the movable core 14.

DESCRIPTION OF SYMBOLS 10 ... Injection molding apparatus 12 ... Convex mold 14 ... Movable core 16 ... Concave mold 26 ... Cavity 30 ... Heat medium passage 32 ... Refrigerant passage 34 ... Heating temperature controller 36 ... Heating medium supply line 38 ... Cooling temperature controller 40 ... Refrigerant supply line 44 ... Control circuit 46 ... Return line 50 ... First three-way valve 52 ... Direction change line 54 ... Heat circulation line 56 ... First on-off valve 58 ... Second on-off valve 60 ... Second three-way valve 62 ... Refrigerant Circulation line 64 ... Third three-way valve 66 ... Compressed air source 68 ... Air supply line 70 ... Drain line 72 ... Molten resin material

Claims (10)

In an injection molding method for injecting a molten resin material (72) and cooling and curing to obtain a resin molded product,
A mold provided with a heat medium passage (30) for circulating a heating medium for heating the molten resin material (72) and a refrigerant passage (32) for circulating a cooling medium for cooling the molten resin material (72). Forming a cavity (26) using (14); and
The temperature of the molten resin material (72) is adjusted while the temperature is adjusted by the heating temperature controller (34) and the heating medium supplied through the heating medium supply line (36) is circulated through the heating medium passage (30). Injecting into the cavity (26);
After the injection is completed, the communication between the heating medium supply line (36) and the heating medium passage (30) is cut off, and the heating medium is sealed in the heating medium passage (30), while the heating medium is used. The heating medium supplied from the temperature controller (34) to the heating medium supply line (36) is heated through the heating medium circulation line (54) provided in the heating medium supply line (36). While returning to the adjuster (34), the cooling medium whose temperature is adjusted by the cooling temperature adjuster (38) is circulated through the refrigerant passage (32), and the molten resin material (72 in the cavity (26)). Cooling process for cooling)
A blow step of stopping the flow of the cooling medium in the refrigerant passage (32) after the cooling is completed and blowing the cooling medium in the refrigerant passage (32) with a blow fluid;
An injection molding method characterized by comprising:   The refrigerant supply line (40) according to claim 1, wherein the cooling medium is supplied from the cooling temperature controller (38) to the refrigerant passage (32) during the injection process. The injection molding method is characterized by returning to the cooling temperature controller (38) through the refrigerant circulation line (62) provided in the above.   3. The injection molding method according to claim 2, wherein the cooling medium is returned to the cooling temperature controller (38) through the refrigerant circulation line (62) during the blowing step. Method.   The injection molding method according to any one of claims 1 to 3, wherein oil is used as the heating medium and water is used as the cooling medium. In an injection molding apparatus (10) for injecting a molten resin material (72) and cooling and curing to obtain a resin molded product,
A cavity (26) to which the molten resin material (72) is supplied is formed, a heat medium passage (30) for circulating a heating medium for heating the molten resin material (72), and the molten resin material (72). A mold (14) provided with a refrigerant passage (32) for circulating a cooling medium for cooling
A heating temperature controller (34) for controlling the temperature of the heating medium;
A heating medium supply line (36) for supplying the heating medium from the heating temperature controller (34) to the heating medium passage (30);
A heating medium circulation line (54) branched from the heating medium supply line (36) and returning the heating medium to the heating temperature controller (34);
A switching valve (50) for selectively bringing the heat medium supply line (36) into a communication state or a communication cut-off state with respect to the heat medium passage (30) or the heat medium circulation line (54);
A cooling temperature controller (38) for controlling the temperature of the cooling medium;
A refrigerant supply line (40) for supplying the cooling medium from the cooling temperature controller (38) to the refrigerant passage (32);
From the state in which the heating medium flows through the heat medium passage (30) to the state in which the cooling medium flows through the refrigerant passage (32), and from the state where the cooling medium flows through the refrigerant passage (32). A control unit (44) for switching to a state in which the heating medium flows in the heat medium passage (30);
A blow fluid supply source (66) for supplying a blow fluid for blowing the cooling medium in the refrigerant passage (32);
An injection molding apparatus (10) comprising:   The injection molding apparatus (10) according to claim 5, wherein the control unit (44) is configured so that the heating medium flows into the heat medium passage (30) from a state where the cooling medium flows through the refrigerant passage (32). The injection molding apparatus (10), wherein the blow fluid is supplied when the state is switched to the above state. The injection molding apparatus (10) according to claim 5 or 6, further comprising a refrigerant circulation line (62) for branching from the refrigerant supply line (40) and returning the cooling medium to the cooling temperature controller (38). And a switching valve (60) for selectively bringing the refrigerant supply line (40) into a communication state or a communication cut-off state with respect to the refrigerant passage (32) or the refrigerant circulation line (62),
An injection molding apparatus (10) comprising:   The injection molding device (10) according to claim 7, wherein when the heating medium flows through the heat medium passage (30), the cooling medium flows through the refrigerant circulation line (62) from the refrigerant supply line (40). Then, the injection molding apparatus (10) is returned to the cooling temperature controller (38).   The injection molding apparatus (10) according to claim 7 or 8, wherein when the cooling medium in the refrigerant passage (32) is blown by the blow fluid, the cooling medium is supplied from the refrigerant supply line (40) to the refrigerant. An injection molding apparatus (10) characterized by returning to the cooling temperature controller (38) through a circulation line (62).   The injection molding apparatus (10) according to any one of claims 5 to 9, wherein oil is supplied as the heating medium and water is supplied as the cooling medium. .

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