JP2016175204A - Injection foam molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection foam molding machine capable of producing a foam molded article having good appearance quality at a low cost.SOLUTION: At least a part of a surface forming a cavity 6 is formed of a porous body 10. A stationary mold 4 or a movable mold 5 forms a physical foaming agent introduction path 41 communicating with the cavity 6 through minute holes that the porous body 10 has, and a core member 81 is installed so that one end thereof can enter/leave the cavity 6. A molten resin from an injection unit 3 is injected to and filled in the cavity 6, then, the physical foaming agent from a physical foaming material feed device 7 is fed, then, the core member 81 is retreat-driven by a core drive mechanism 82, and pressure in the cavity 6 is reduced. Thus, the physical foaming agent is made to foam and a foam-molded article of a prescribed shape is molded.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an injection foam molding machine, and more particularly to a configuration of a mold apparatus capable of molding a foam molded product by injecting a physical foam into molten resin injected and filled into a cavity from an injection unit.

  Conventionally, carbon dioxide and nitrogen in a supercritical state (in the present specification, these are collectively referred to as “physical foaming agent”) are injected into a molten resin stored in a heating cylinder, and the molten resin is injected into the molten resin. A mixture in which the physical foaming agent is uniformly dissolved is produced, and the obtained mixture is injected and filled into a cavity of a mold apparatus to form a resin molded body containing fine bubbles (in this specification, this resin molding). There is known a method for producing a body called “foamed molded product”. When a mixture of the molten resin and the physical foaming agent generated in the heating cylinder is injected into the cavity, a large number of bubble nuclei are generated in the molten resin due to a rapid pressure drop. The mixture of the molten resin and the physical foaming agent injected into the cavity flows and fills the cavity while increasing the volume by expanding the bubbles. Bubbles in the molten resin increase in diameter as they move away from the gate and release gas while violently bursting at the flow end. When the filling amount of the mixture in the cavity increases and the in-mold pressure increases, the bubbles are compressed and the coarsened bubbles are also reduced in size. Thereby, a foaming molded product is shape | molded. This forming method is called a MuCell (registered trademark) process (for example, refer to the abstract of Patent Document 1). According to the MuCell process, it is possible to reduce the weight of the resin molded product, improve the dimensional stability, prevent warpage and sink marks, etc., compared to the case of using a general injection molding method.

  The applicant of the present application has previously incorporated a sleeve made of a porous material in a heating cylinder head as an injection unit of an injection foam molding machine, and physically passes the sleeve through molten resin flowing in a resin passage formed in the sleeve. The thing which inject | pours a foaming agent was proposed (for example, refer the summary of patent document 2). When the injection unit of this configuration is provided, the contact area between the molten resin and the physical foaming agent can be increased as compared with the case where the physical foaming agent is injected into the molten resin through the physical foaming agent injection hole provided in the heating cylinder. The diffusion rate of the physical foaming agent into the molten resin can be increased, the molding shot cycle can be shortened, and the productivity of the foam molded product can be increased.

JP 2005-271468 A JP 2012-232558 A

  However, since the injection foam molding machines described in Patent Documents 1 and 2 are both configured to inject and fill a mixture of molten resin and physical foaming agent generated on the injection unit side into the cavity, When the bubbles burst in contact with the cavity surface, rupture marks are formed along the flow direction of the mixture, and an appearance defect called swirl mark tends to occur in the foamed molded product. In addition, according to the injection foam molding machine described in Patent Documents 1 and 2, in a plane portion where the curing rate of the resin is relatively slow, the bubble rupture mark becomes a clean circle, but the curing rate of the resin is relatively fast. In corners and the like, the bubble rupture marks tend to be elliptical, and from this point, the appearance quality of the foamed molded product tends to deteriorate.

  In addition, since the injection foam molding machine described in Patent Document 1 is configured to inject a physical foaming agent into the heating cylinder, the length of the heating cylinder and the screw is necessarily provided in a general injection molding machine. Be bigger than things. For this reason, an existing general injection molding machine cannot be remodeled into an injection foam molding machine, and an expensive dedicated machine is required for manufacturing foam molded products.

  The present invention has been made to solve such problems of the prior art, and an object of the present invention is to provide an injection foam molding machine capable of producing a foam molded article with good appearance quality at low cost. .

  In order to solve the above problems, the present invention injects and fills a mold opening / closing / clamping unit for opening / closing and clamping a mold apparatus, and a fixed amount of molten resin in a cavity of the mold apparatus clamped. In an injection foam molding machine comprising an injection unit and a physical foaming agent supply device for supplying a physical foaming agent into a molten resin, the physical foaming agent supplied from the physical foaming agent supply device is supplied to the mold device. In addition to forming a physical foaming agent introduction path to be introduced into the cavity, injection and filling of molten resin from the injection unit into the cavity, and supply of the physical foaming agent from the physical foaming agent supply device into the cavity A vacuum device is provided that decompresses the inside of the cavity and foams the physical foaming agent in the molten resin after completion.

  According to this configuration, since the molten resin supplied from the injection unit and the physical foaming agent supplied from the physical foaming agent supply device are mixed in the cavity of the mold apparatus, the molten resin generated in the injection unit and the physical The flow of the mixture does not occur in the cavity as in the case of injecting and filling the foaming agent mixture into the cavity. For this reason, generation | occurrence | production of the swirl mark and elliptical rupture trace resulting from the flow of a mixture can be prevented, and the external appearance quality of a foaming molded product can be improved. Since the die unit is equipped with a decompression device, after injecting the physical foaming agent into the cavity filled with the molten resin, the decompression device is operated to decompress the cavity, so that many Bubbles can be generated. Moreover, since the physical foaming agent is supplied into the cavity of the mold apparatus, it is possible to divert the heating cylinder and screw provided in the existing general injection molding machine as it is, and the injection foam molding machine can be made inexpensive. Can be manufactured.

  Further, the present invention is the injection foam molding machine having the above-described configuration, wherein all or part of the surface constituting the cavity is constituted by a porous body having an area larger than the cross-sectional area of the physical foaming agent introduction path, The tip of the physical foaming agent introduction path is communicated with a part of fine pores of the porous body.

  According to this configuration, the physical foaming agent introduced into the physical foaming agent introduction path from the physical foaming agent supply device can be introduced into the fine pores of the porous body. The physical foaming agent introduced into the fine pores of the porous body is expanded in the surface direction of the porous body through the pores and supplied into the cavity. Therefore, compared with the case where the physical foaming agent is supplied directly into the cavity from the physical foaming agent introduction path, the contact area of the physical foam with the molten resin can be expanded, and the physical foaming agent can be diffused into the molten resin. Since it can be made uniform and quick, the shot cycle of molding can be shortened, and the productivity of the foam molded product can be improved.

  In the injection foam molding machine having the above-described configuration, the decompression device is attached to the mold device so as to be able to move forward and backward, and a core member disposed so that one end can be moved in and out of the cavity; What comprises the core member which comprises the core drive mechanism which drives the said core member forward and backward with respect to the said cavity is characterized by the above-mentioned.

  According to this configuration, the pressure in the cavity can be reduced by retracting the core member that has been projected into the cavity at the time of injection / filling of the molten resin after supplying the physical foaming material, so that the physical foaming agent can be foamed. it can.

  Further, the present invention is the injection foam molding machine having the above-described configuration, characterized in that the pressure reducing device includes a pressure reducing pipe having one end communicating with the cavity and a pressure reducing valve for opening and closing the pressure reducing pipe. To do.

  According to this configuration, the pressure in the cavity can be reduced by closing the pressure reducing tube with the pressure reducing valve at the time of injection / filling of the molten resin and opening the pressure reducing tube with the pressure reducing valve after supplying the physical foaming material. Can be foamed.

  In the injection foam molding machine configured as described above, the pressure reducing device may include the mold opening / closing / clamping unit and a controller for controlling the driving of the mold opening / closing / mold clamping unit. After the injection and filling of the molten resin from the injection unit into the cavity and the supply of the physical foaming agent into the cavity from the physical foaming agent supply device are completed, the mold clamping force of the mold apparatus is reduced. And driving the mold opening / closing / clamping unit.

  According to this configuration, the mold apparatus is clamped with a predetermined clamping force at the time of injection / filling of the molten resin, and the mold is injected after the injection / filling of the molten resin into the cavity and the supply of the physical foam material are completed. Since the pressure in the cavity can be reduced by reducing the mold clamping force of the apparatus, the physical foaming agent can be foamed.

  In the injection foam molding machine configured as described above, the porous body is formed of a porous sintered metal material having a porosity of 5% to 60%.

  The porosity of the porous body is closely related not only to the permeation performance of the physical foaming agent but also to the strength of the porous body. When the porosity of the porous body is 5% or less, the molten resin If the physical foaming material is not supplied quickly and sufficiently and exceeds 60%, insufficient strength of the porous material becomes a problem. For this reason, by forming with a porous sintered metal material having a porosity of 5% to 60%, the permeation performance of the physical foaming agent and the mechanical strength of the porous body can be balanced. Further, since the porous sintered metal material has high strength, it does not adversely affect the life of the mold apparatus.

  Since the injection foam molding machine of the present invention mixes the molten resin supplied from the injection unit and the physical foaming agent supplied from the physical foaming agent supply device in the cavity of the mold device, the foamed molded product has high appearance quality. Can be molded.

It is a block diagram of the injection foam molding machine which concerns on embodiment. It is sectional drawing which shows the 1st example of the metal mold apparatus with which the injection foam molding machine which concerns on embodiment is equipped. It is a flowchart which shows the 1st example of the operation | movement procedure of the injection foam molding machine which concerns on embodiment. It is sectional drawing which shows the 2nd example of the metal mold apparatus with which the injection foam molding machine which concerns on embodiment is equipped. It is a flowchart which shows the 2nd example of the operation | movement procedure of the injection foam molding machine which concerns on embodiment.

  First, the configuration of the injection foam molding machine according to the embodiment will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the injection foam molding machine of this example includes a frame 1, a mold opening / closing / mold clamping unit 2 and an injection unit 3 mounted on the frame 1, and a mold opening / closing / mold clamping unit 2. And a physical foaming material for supplying a physical foaming agent into a cavity 6 formed between the fixed mold 4 and the movable mold 5 which are clamped. A supply device 7; a decompression device 8 for reducing the pressure in the cavity 6; and a controller 9 for controlling the driving of the mold opening / closing and clamping unit 2, the injection unit 3, the physical foam material supply device 7 and the decompression device 8. Have.

  The frame 1 is formed in a box shape using mold steel and a plate material (not shown), and a controller 8, a power supply device (not shown), piping, wiring, and the like are accommodated therein.

  The mold opening / closing / clamping unit 2 is arranged opposite to each other with a predetermined interval, and is fixed between the tail stock 21 and the fixed die plate 22 fixed on the frame 1, and between the tail stock 21 and the fixed die plate 22. A movable die plate 23 slidably mounted on the frame 1, a toggle link mechanism 24 having both ends connected to the tail stock 21 and the movable die plate 23, and an electric servo motor for mold opening / closing and clamping 25, and a ball screw mechanism 26 that converts the rotational force of the mold opening / closing / clamping electric servomotor 25 into the driving force of the toggle link mechanism 24. A fixed die 4 is mounted on the fixed die plate 22, and a movable die 5 is mounted on the movable die plate 23. Note that an unillustrated ejecting device for taking out a molded product from the mold apparatus is provided in the vicinity of the mold apparatus including the fixed mold 4 and the movable mold 5.

  In the above configuration, when the mold opening / closing / clamping electric servomotor 25 is rotationally driven in one predetermined direction, the screw shaft of the ball screw mechanism 26 advances and the toggle link mechanism 24 expands to a predetermined mold opening position. When the movable mold 5 that has been moved back moves forward in the direction approaching the fixed mold 4 and the toggle link mechanism 24 is fully extended, the fixed mold 4 and the movable mold 5 have a predetermined clamping force. The mold is clamped at. As a result, it is possible to inject and fill the molten resin into the cavity 6 formed between the fixed mold 4 and the movable mold 5 and to supply the physical foam material. When the mold opening / closing / clamping electric servomotor 25 is driven in reverse after the molding is completed, the screw shaft of the ball screw mechanism 26 is retracted, the toggle link mechanism 24 is contracted, and the movable mold 5 is separated from the fixed mold 4. To return to the mold open position. As a result, the molded product can be taken out by the ejecting apparatus.

  The injection device 3 includes a heating cylinder 32 having an injection nozzle 31 attached to the tip, a screw 33 housed in the heating cylinder 32 so as to be rotatable and capable of moving forward and backward, and a screw for rotationally driving and driving the screw 33 forward and backward. A drive unit 34, a hopper 35 for storing the raw material resin, a hopper block 36 for supplying the raw material resin stored in the hopper 35 into the heating cylinder 32, and a band heater 37 wound around the outer periphery of the heating cylinder 32 It is mainly composed. The injection nozzle 31 is pressed against the fixed mold 4 during continuous operation.

  When the screw 33 is rotationally driven in the heating cylinder 32, the raw material resin in the hopper 35 is introduced into the heating cylinder 32 accordingly. The raw material resin introduced into the heating cylinder 32 is melted by frictional heat and shearing heat generated by the rotational drive of the screw 33 and heat generated by the band heater 37 and is stored in the tip portion of the heating cylinder 32 sequentially. A predetermined amount of molten resin stored at the tip of the heating cylinder 32 is injected and filled into the cavity 6 by driving the screw 33 forward.

As shown in FIG. 1, the physical foam material supply device 7 includes a gas cylinder 71 for storing a source gas such as CO ₂ gas and N ₂ gas, and a source gas supplied from the gas cylinder 71 at a high temperature and a high pressure to achieve physical properties in a supercritical state. A supercritical fluid generator 72 as a foaming agent, a physical foam material supply nozzle 73 for injecting a physical foaming agent supplied from the supercritical fluid generator 72 into the cavity 6, a supercritical fluid generator 72, and a physical foam material It comprises an on-off valve 75 provided in a pipe line 74 connecting the supply nozzle 73. The physical foaming material supply nozzle 73 is attached to a mold apparatus including the fixed mold 4 and the movable mold 5. In the example of FIG. 1, only one physical foaming material supply nozzle 73 is attached to the mold apparatus, but a plurality of physical foaming agent supply nozzles 73 may be attached to the mold apparatus. The on-off valve 75 is opened and closed once every time molten resin is injected into the cavity 6, and supplies a predetermined amount of physical foaming agent into the cavity 6 through the physical foam material supply nozzle 73.

  The controller 9 drives and stops the mold opening / closing / mold clamping electric servo motor 25 provided in the mold opening / closing / mold clamping unit 2, drives / stops the screw driving unit 34 provided in the injection unit 3, and the physical foam material supply device 7. The control and control of the supercritical fluid generator 72 and the on-off valve 75 and the decompression device 8 and the ejector (not shown) are controlled continuously and automatically. Molding.

  As shown in FIGS. 2A and 2B, the fixed mold 4 and the movable mold 5 have at least a surface constituting the cavity 6 (in this specification, this surface is referred to as a “cavity surface”). A part is composed of the porous body 10. In the example of FIG. 2, the porous body 10 is formed only on the fixed mold 4, but the porous body 10 may be formed on both the fixed mold 4 and the movable mold 5. In the case where the porous body 10 is formed in both the fixed mold 4 and the movable mold 5, the porous body 10 on the fixed mold 4 side and the porous body 10 on the movable mold 5 side are mutually connected during mold clamping. Each porous body 10 can be formed in the position which contacts. By doing so, it is formed on both the fixed mold 4 side and the movable mold 5 side through one physical foam material introduction path formed on either the fixed mold 4 side or the movable mold 5 side. Since the physical foaming agent can be introduced into the porous body 10, the configuration of the mold apparatus can be simplified. The formation area of the porous body 10 is set such that a predetermined amount of physical foam can be diffused into the molten resin in the cavity 6 within a predetermined time.

  The porous body 10 can be formed by performing laser processing on required portions of the fixed mold 4 and the movable mold 5. That is, when an aggregate of metal powders (including alloy powders) is irradiated with a predetermined level of laser, the individual metal powders are locally melted by the heat and become porous sintered metals after solidification. The metal powder is dispersed in the required portions of the fixed mold 4 and the movable mold 5 processed into the shape of the above, and the dispersed metal powder is irradiated with a laser to thereby obtain the fixed mold 4 and the movable mold. The porous body 10 can be formed on the surface of 5. When the porous body 10 having a required thickness cannot be formed by one operation, the dispersion of the metal powder and the laser irradiation are repeated as many times as necessary until the thickness of the porous body 10 reaches a required size. The porosity of the porous body 10 can be adjusted by changing the laser power.

  The porosity of the porous body 10 is adjusted to 5% to 60% in order to balance the physical foaming agent permeability and the mechanical strength of the porous body 10. That is, when the porosity is 5% or less, the mechanical strength of the porous body 10 is increased, but it is difficult to quickly and sufficiently supply the physical foam material into the cavity 6. On the other hand, when the porosity exceeds 60%, the physical foam material can be easily supplied into the cavity 6, but the mechanical strength of the porous body 10 tends to be insufficient. For this reason, the porosity of the porous body 10 is adjusted to 5% to 60%.

  The fixed mold 4 is formed with a physical foaming agent introduction path 41 having one end reaching the porous body 10, and the other end of the physical foaming agent introduction path 41 has a mounting port 42 of the physical foaming material supply nozzle 73. It is formed. In addition, a sprue 43 that guides the molten resin injected from the injection unit 3 into the cavity 6 is opened in the other part of the fixed mold 4. On the other hand, the movable mold 5 is provided with an installation hole 51 for the core member 81 constituting the decompression device 8. Since the mold apparatus is configured as described above, the molten resin injected from the injection apparatus 3 is injected and filled into the cavity 6 through the sprue 43. Further, when the opening / closing valve 75 of the physical foam material supply device 7 is opened with the physical foam material supply nozzle 73 attached to the attachment port 42, the physical foam (supercritical fluid) generated by the supercritical fluid generation device 72. Reaches the porous body 10 through the physical foaming agent introduction path 41. The physical foam that has reached the porous body 10 extends in the surface direction of the porous body 10 through the fine pores of the porous body 10 and is supplied into the cavity 6.

  As shown in FIGS. 2A and 2B, the decompression device 8 includes a core member 81 installed in the installation hole 51 so as to be capable of moving forward and backward, and a core drive mechanism 82 for driving the core member 81 forward and backward. Consists of As the core drive mechanism 82, an electric mechanism such as a solenoid or a hydraulic mechanism such as a hydraulic cylinder can be used. The core member 81 protrudes into the cavity 6 until the molten resin is injected and filled into the cavity 6 and the physical foaming agent is supplied into the cavity 6 as shown in FIG. Then, at a predetermined timing after the physical foaming agent is supplied into the cavity 6, as shown in FIG. 2 (b), the tip end surface is retracted to a position flush with the cavity surface. Thereby, the inside of the cavity 6 is decompressed, and the physical foaming agent supplied into the molten resin is foamed.

  Hereinafter, the operation of the injection foam molding machine according to the embodiment will be described with reference to FIG. The operation of each part constituting the injection foam molding machine is executed by a command signal from the controller 9.

  First, in a standby state before an automatic operation is instructed by an operator, the toggle link mechanism 24 is contracted, the movable mold 5 is in a predetermined retracted position, and the fixed mold 4 and the movable mold 5 are The mold is open. Further, the supercritical fluid generating device 72 generates a physical foaming agent before an automatic operation is instructed by an operator. Further, the core member 81 protrudes into the cavity 6.

  From this state, when an automatic operation is instructed by the operator, the controller 9 drives the mold opening / closing / clamping electric servomotor 25 to rotate in a predetermined direction to extend the toggle link mechanism 24, thereby moving the movable mold 5. Is advanced in the installation direction of the fixed mold 4 (step S1). When the movable mold 5 advances to a predetermined position, the fixed mold 4 and the movable mold 5 are in the mold closed state, but the mold opening / closing / clamping electric servo motor 25 is further rotated in the same direction. The toggle link mechanism 24 is fully extended. As a result, the fixed mold 4 and the movable mold 5 are clamped, and a cavity 6 having a predetermined shape is formed between the fixed mold 4 and the movable mold 5.

  After the mold clamping, the screw 33 is driven forward by the screw driving unit 34, and a certain amount of molten resin stored in the heating cylinder 32 is injected and filled into the cavity 6 through the injection nozzle 31 and the sprue 43 ( Step S2). After the injection and filling of the molten resin, the opening / closing valve 75 is opened, and the physical foaming agent generated by the supercritical fluid generator 72 is transferred to the pipe 74, the physical foaming agent supply nozzle 73, the physical foaming material introduction passage 41, and the porous material. The material 10 is supplied into the cavity 6 through the material 10 (step S3).

  After that, the core member 81 is driven backward by the core drive mechanism 82, and the inside of the cavity 6 is decompressed (step S4). As a result, the core of the physical foaming agent dispersed in the molten resin grows into bubbles and foams the molten resin, so that a foam molded product having a predetermined shape is formed (step S5).

  After molding the foam molded product, the mold opening / closing / clamping electric servomotor 25 is driven in reverse to contract the toggle link mechanism 24, and the movable mold 5 is returned to the predetermined retracted position (step S6). As a result, the fixed mold 4 and the movable mold 5 are in the mold open state, and therefore an ejecting device (not shown) is driven to take out the foam molded product from the movable mold 5 (step S7). The above operation is continued until a preset number of shots is reached.

  The injection foam molding machine according to the embodiment generates a mixture of a molten resin and a physical foaming agent in the cavity 6, so that no flow of the mixture occurs in the cavity 6, and a swirl mark or an elliptical burst mark is generated. Can be prevented, and the appearance quality of the foam molded product can be improved. Further, since the physical foaming agent is supplied into the cavity 6, the heating cylinder and screw provided in the existing general injection molding machine can be used as they are, and the injection foam molding machine can be manufactured at low cost.

  In addition, this invention is not limited to the invention described in the said embodiment, A change can be suitably added in the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the pressure reducing device 8 includes the core member 81 and the core drive mechanism 82 that drives the core member 81 forward and backward. However, a pressure reducing device having another configuration may be used. Of course it is possible. As another example of the decompression device 8, as shown in FIG. 4, a decompression pipe 83 having one end communicating with the cavity 6 and the other end opened to the atmosphere, and a decompression valve 84 for opening and closing the decompression pipe 83. Can be mentioned. The pressure reducing valve 84 is closed until the supply of the physical foaming agent into the cavity 6 is completed (step S3 in FIG. 3), and is opened at a predetermined timing after the supply of the physical foaming agent into the cavity 6 is completed. Manipulate. Thereby, the physical foaming agent dispersed in the molten resin is foamed.

  Further, the pressure reducing device 8 may be configured to use the mold opening / closing / clamping unit 2 and the controller 9 instead of the structure using the core member 81 and the core driving mechanism 82, the pressure reducing pipe 83 and the pressure reducing valve 84. In this case, as shown in FIG. 5, after the supply of the physical foam material into the cavity 6 is completed in step S13, the process proceeds to step S14, and the mold opening / closing / clamping electric servomotor 25 is moved in the mold opening direction. Is driven by a predetermined rotation amount. Thereby, since the inside of the cavity 6 is decompressed, the physical foaming agent dispersed in the molten resin is foamed. Note that steps S11 to S13 and steps S15 to S17 in FIG. 5 correspond to steps S1 to S3 and steps S5 to S7 in FIG. Description of these steps will be omitted to avoid duplication.

  INDUSTRIAL APPLICABILITY The present invention can be used for an injection foam molding machine that is applied to manufacture of a foam molded product.

  DESCRIPTION OF SYMBOLS 1 ... Frame, 2 ... Mold opening / closing and clamping unit, 3 ... Injection unit, 4 ... Fixed mold, 5 ... Movable mold, 6 ... Cavity, 7 ... Physical foam supply apparatus, 8 ... Decompression device, 9 ... Controller DESCRIPTION OF SYMBOLS 10 ... Porous body, 21 ... Tail stock, 22 ... Fixed die plate, 23 ... Movable die plate, 24 ... Toggle link mechanism, 25 ... Electric servomotor for mold opening / closing and clamping, 26 ... Ball screw mechanism, 31 ... Injection nozzle, 32 ... heating cylinder, 33 ... screw, 34 ... screw drive, 35 ... hopper, 36 ... hopper block, 37 ... band heater, 41 ... physical foaming agent introduction path, 42 ... nozzle mounting port, 43 ... sprue, DESCRIPTION OF SYMBOLS 51 ... Installation hole, 71 ... Gas cylinder, 72 ... Supercritical fluid production | generation apparatus, 73 ... Physical foaming material supply nozzle, 74 ... Pipe line, 75 ... Open / close valve, 81 ... Core member, 82 ... Core drive mechanism

Claims (6)

Mold opening / closing / clamping unit for opening / closing and clamping the mold apparatus, injection unit for injecting / filling a certain amount of molten resin into the cavity of the mold apparatus that has been clamped, and physical foaming agent in the molten resin In an injection foam molding machine equipped with a physical foaming agent supply device for supplying
In the mold apparatus, a physical foaming agent introduction path for introducing the physical foaming agent supplied from the physical foaming agent supply device into the cavity is formed, and injection of molten resin from the injection unit into the cavity is performed. After completion of filling and supply of the physical foaming agent into the cavity from the physical foaming agent supply device, a decompression device is provided that decompresses the inside of the cavity to foam the physical foaming agent in the molten resin. And injection foam molding machine.   All or part of the surface constituting the cavity is formed of a porous body having an area larger than the cross-sectional area of the physical foaming agent introduction path, and the porous body has a tip of the physical foaming agent introduction path. 2. The injection foam molding machine according to claim 1, wherein the injection foam molding machine communicates with a part of a fine hole.   As the pressure reducing device, a core member that is attached to the mold device so as to be able to move back and forth, and is arranged so that one end thereof can enter and leave the cavity, and a core that drives the core member to move forward and backward with respect to the cavity The injection foam molding machine according to any one of claims 1 and 2, further comprising a drive mechanism.   3. The pressure reducing device according to claim 1, further comprising: a pressure reducing pipe having one end communicating with the inside of the cavity and a pressure reducing valve that opens and closes the pressure reducing pipe. The injection foam molding machine described.   As the pressure reducing device, the mold opening / closing / clamping unit and a controller for controlling the driving of the mold opening / closing / clamping unit are used. The controller injects / fills molten resin from the injection unit into the cavity. And after the supply of the physical foaming agent from the physical foaming agent supply device into the cavity is completed, the mold opening / closing and clamping unit is driven so as to reduce the mold clamping force of the mold device. The injection foam molding machine according to any one of claims 1 and 2.   The injection foam molding machine according to any one of claims 2 to 5, wherein the porous body is formed of a porous sintered metal material having a porosity of 5% to 60%.