Injection molding device and mold for injection molding device

Abstract

To cut a gate at a targeted position.SOLUTION: An injection molding device has a fixed mold and a movable mold facing the fixed mold, and includes: a mold having a cavity demarcated by the fixed mold and the movable mold, and a runner communicating with the cavity; a mold clamping section for moving the movable mold with respect to the fixed mold; an injection section for injecting the molding material into the cavity through the runner; a cutting mechanism provided in the mold and having a cutter protruding into the runner; a drive section provided in the mold and driving the cutting mechanism; and a control section for controlling the injection section, the clamping section, and the drive section. The control section controls the injection section to inject the molding material into the cavity, and then controls the drive section to protrude the cutter into the runner to cut the hardened molding material in the runner.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to an injection molding apparatus and a mold for the injection molding apparatus. [Background technology]

[0002] Patent Document 1 discloses a tunnel gate type mold having a tunnel gate that connects a runner and a cavity. In this mold, when the mold is opened, the movable mold moves relative to the fixed mold, cutting the molding material that has hardened in the tunnel gate, thereby separating the molding material that has hardened in the cavity from the molding material that has hardened in the sprue and runner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-039491 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in the above document, in a tunnel gate type mold, the molding material hardened in the cavity can be automatically separated from the molding material hardened in the runner by the movement of the movable mold. However, the molding material may be torn off by the movement of the movable mold, and the molding material may not be separated at the intended position. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided an injection molding apparatus. The injection molding apparatus includes: a molding die having a fixed die and a movable die facing the fixed die, the mold having a cavity defined by the fixed die and the movable die and a runner communicating with the cavity; a clamping unit that moves the movable die relative to the fixed die; an injection unit that injects molding material into the cavity via the runner; a cutting mechanism provided in the molding die and having a cutter that protrudes into the runner; a drive unit that is provided in the molding die and drives the cutting mechanism; and a control unit that controls the injection unit, the clamping unit, and the drive unit. The control unit controls the injection unit to inject the molding material into the cavity, and then controls the drive unit to cause the cutter to protrude into the runner, thereby cutting the molding material that has hardened in the runner.

[0006] According to a second aspect of the present disclosure, there is provided a molding die for an injection molding apparatus. The molding die for the injection molding apparatus includes a fixed die, a movable die that faces the fixed die and moves relative to the fixed die, a cutting mechanism having a cutter, and a drive unit that drives the cutting mechanism. The fixed die and the movable die define a cavity into which a molding material is injected, and at least one of the fixed die and the movable die is provided with a runner that communicates with the cavity. After the molding material is injected into the cavity through the runner, the cutting mechanism is driven by the drive unit to cause the runner to protrude the cutter, thereby cutting the molding material that has hardened within the runner. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a front view showing a schematic configuration of an injection molding apparatus according to a first embodiment. [Figure 2] 1 is a cross-sectional view showing a schematic configuration of an injection molding apparatus according to a first embodiment. [Figure 3] FIG. 2 is a perspective view showing a schematic configuration of a flat screw. [Figure 4] FIG. 2 is a plan view showing a schematic configuration of a barrel. [Figure 5]FIG. 2 is a perspective view showing a schematic configuration of a movable mold according to the first embodiment. [Figure 6] FIG. 2 is a first perspective view showing the configuration of the cutting mechanism of the first embodiment. [Figure 7] FIG. 2 is a second perspective view showing the configuration of the cutting mechanism of the first embodiment. [Figure 8] 4 is a flowchart showing the contents of an injection molding process according to the first embodiment. [Figure 9] FIG. 1 is a first explanatory diagram showing the injection molding process of the first embodiment. [Figure 10] FIG. 2 is a second explanatory view showing the injection molding process of the first embodiment. [Figure 11] FIG. 3 is a third explanatory view showing the injection molding process of the first embodiment. [Figure 12] FIG. 4 is a fourth explanatory view showing the injection molding process of the first embodiment. [Figure 13] FIG. 5 is a fifth explanatory view showing the injection molding process of the first embodiment. [Figure 14] FIG. 10 is a perspective view showing a schematic configuration of a cutting mechanism according to a second embodiment. [Figure 15] FIG. 11 is a first cross-sectional view showing a schematic configuration of a cutting mechanism according to a third embodiment. [Figure 16] FIG. 11 is a second cross-sectional view showing a schematic configuration of the cutting mechanism of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is a front view showing a schematic configuration of an injection molding apparatus 10 in a first embodiment. FIG. 1 shows arrows indicating mutually orthogonal X, Y, and Z directions. The X and Y directions are parallel to a horizontal plane, and the Z direction is opposite to the direction of gravity. The X, Y, and Z directions shown in FIG. 2 and subsequent figures correspond to the X, Y, and Z directions shown in FIG. 1. In the following description, when specifying a direction, positive and negative signs are used in combination to indicate the direction indicated by the arrow, with "+" indicating the positive direction and "-" indicating the negative direction opposite to the direction indicated by the arrow.

[0009] The injection molding apparatus 10 includes an injection unit 100, a mold clamping unit 200, a molding die 300, a refrigerant supply unit 400, and a control unit 500. In this embodiment, the injection unit 100, the mold clamping unit 200, the refrigerant supply unit 400, and the control unit 500 are fixed to a base 20. An operation panel 30 is provided on the front of the base 20.

[0010] A hopper 101 into which molding material, which is the material for the molded product, is charged is connected to the injection unit 100. For example, pellet-like or powder-like molding material is charged into the hopper 101. For example, a thermoplastic resin or a thermoplastic elastomer is used as the molding material.

[0011] The molding die 300 has a fixed die 310 and a movable die 320 that faces the fixed die 310. The fixed die 310 and the movable die 320 are each fixed to the mold clamping unit 200. The molding die 300 has a cavity defined by the fixed die 310 and the movable die 320, and a runner that communicates with the cavity. The mold clamping unit 200 opens and closes the molding die 300 by moving the movable die 320 relative to the fixed die 310.

[0012] The injection section 100 plasticizes the molding material supplied from the hopper 101 and injects the plasticized molding material into the cavity via a runner. "Plasticization" is a concept that includes melting, and refers to changing from a solid to a fluid state. Specifically, for materials that undergo glass transition, plasticization refers to raising the temperature of the material above its glass transition point. For materials that do not undergo glass transition, plasticization refers to raising the temperature of the material above its melting point. The molding material is injected into the cavity, where it cools and hardens, producing the molding material.

[0013] Coolant supply unit 400 is connected to casting mold 300 by piping (not shown), and supplies a coolant to casting mold 300 via the piping. In this embodiment, coolant supply unit 400 is configured by a chiller. Water is used as the coolant.

[0014] The control unit 500 controls the injection unit 100, the mold clamping unit 200, the coolant supply unit 400, and a drive unit 340 that drives the cutting mechanism 330, which will be described later. The control unit 500 is configured by a computer that includes one or more processors, a main memory device, and an input / output interface that receives and outputs signals from and to the outside. The control unit 500 manufactures molded products by having the processor load a program into the main memory device and execute the injection molding process, which will be described later.

[0015] Fig. 2 is a cross-sectional view showing a schematic configuration of the injection molding apparatus 10. Fig. 2 shows a cross section of the injection section 100, the mold clamping section 200, and the molding die 300. The injection section 100 includes a plasticizing section 110, an injection control mechanism 120, and a nozzle 130.

[0016] The plasticizing section 110 has a function of plasticizing at least a part of the molding material supplied from the hopper 101 to make it into a paste having flowability, and supplying the paste to the injection control mechanism 120 .

[0017] In this embodiment, the plasticizing unit 110 includes a screw driving unit 111 , a screw case 113 , a flat screw 115 , a barrel 116 , and a plasticizing heater 117 .

[0018] The screw driving unit 111 is configured by a motor and a reducer. The screw driving unit 111 is driven under the control of the control unit 500. The screw driving unit 111 is connected to the flat screw 115.

[0019] The flat screw 115 is housed in a space surrounded by the screw case 113 and the barrel 116. The flat screw 115 housed in the space is rotated by a rotational driving force from the screw driving unit 111.

[0020] A communication hole 118 that penetrates the barrel 116 is provided in the center of the barrel 116. An injection cylinder 121, which will be described later, is connected to the communication hole 118. A check valve 124 is provided in the communication hole 118 at a portion upstream of the injection cylinder 121.

[0021] The plasticizing heater 117 is embedded in the barrel 116. The plasticizing heater 117 generates heat when supplied with power, and heats the molding material. The temperature of the plasticizing heater 117 is controlled by the control unit 500.

[0022] FIG. 3 is a perspective view showing a schematic configuration of the flat screw 115. The flat screw 115 has a substantially cylindrical shape. The height of the flat screw 115 along the central axis RX1 is smaller than the diameter of the flat screw 115. The flat screw 115 has a groove-forming surface 150 facing the barrel 116. The groove-forming surface 150 has grooves 152 extending spirally from a central portion 151. The grooves 152 communicate with a material inlet 153 formed on the side surface of the flat screw 115. The molding material supplied from the hopper 101 is introduced into the grooves 152 from the material inlet 153. In this embodiment, three grooves 152 are formed on the groove-forming surface 150. The grooves 152 are separated from each other by a ridge portion 154. The number of grooves 152 is not limited to three, and may be one, two, four, or more. The shape of the groove 152 is not limited to a spiral shape, but may be a helical or involute curve shape, or may be a shape that describes an arc from the center portion 151 to the outer periphery.

[0023] 4 is a plan view showing a schematic configuration of the barrel 116. The barrel 116 has an opposing surface 160 that faces the groove forming surface 150 of the flat screw 115. An opening of the above-mentioned communicating hole 118 is provided in the center of the opposing surface 160. The opening of the communicating hole 118 is provided on an extension of the central axis RX1 of the flat screw 115. The opposing surface 160 is formed with a plurality of guide grooves 161 that are connected to the communicating holes 118 and extend spirally from the communicating holes 118 toward the outer periphery. Note that the guide grooves 161 provided in the opposing surface 160 do not necessarily have to be connected to the communicating holes 118. Furthermore, the opposing surface 160 does not necessarily have to have the guide grooves 161.

[0024] The molding material supplied to the groove 152 of the flat screw 115 is plasticized between the flat screw 115 and the barrel 116 by the rotation of the flat screw 115 and the heat from the plasticizing heater 117, and flows along the groove 152 and the guide groove 161 due to the rotation of the flat screw 115, and is led to the center portion 151 of the flat screw 115. The molding material that has flowed into the center portion 151 is led to the injection control mechanism 120 through the communication hole 118.

[0025] 2, the injection control mechanism 120 includes an injection cylinder 121, a plunger 122, and a plunger driver 123. The injection control mechanism 120 has a function of injecting the molding material supplied from the plasticizing section 110 into the injection cylinder 121 from a nozzle 130. The nozzle 130 is inserted into a through-hole provided in the fixed mold 310. The molding material injected from the nozzle 130 fills a cavity Cv defined between the fixed mold 310 and the movable mold 320.

[0026] Injection cylinder 121 is a substantially cylindrical member connected to communication hole 118 of barrel 116, and has plunger 122 inside. Plunger 122 slides inside injection cylinder 121 by plunger drive unit 123 configured by a motor, and pressure-feeds the molding material inside injection cylinder 121 to nozzle 130. Plunger drive unit 123 is driven under the control of control unit 500.

[0027] The mold clamping unit 200 has a function of moving the movable mold 320 relative to the fixed mold 310, that is, a function of opening and closing the casting mold 300. In this embodiment, the mold clamping unit 200 includes a fixed platen 210, a movable platen 220, tie bars 230, a ball screw unit 240, and a mold drive unit 250.

[0028] The injection unit 100, fixed platen 210, and movable platen 220 are arranged in this order along the X direction. The fixed platen 210 is fixed to the tip of a tie bar 230 that is provided along the X direction. A fixed mold 310 is fixed to the surface of the fixed platen 210 facing the movable platen 220 by, for example, a bolt or a clamp.

[0029] The movable platen 220 is configured to be movable along tie bars 230. The movable platen 220 is connected to a ball screw unit 240 provided along the X direction. A movable mold 320 is fixed to the surface of the movable platen 220 facing the fixed platen 210 by, for example, a bolt or a clamp.

[0030] Mold driving unit 250 is composed of a motor and a reducer. Mold driving unit 250 is driven under the control of control unit 500. Mold driving unit 250 is connected to movable platen 220 via ball screw unit 240. Mold driving unit 250 rotates ball screw unit 240 to move movable platen 320, which is fixed to movable platen 220, relative to fixed platen 310, which is fixed to fixed platen 210, thereby opening and closing forming mold 300.

[0031] The molding die 300 is provided with an ejection mechanism 350 for releasing the molding material that has hardened in the molding die 300 from the movable die 320. The ejection mechanism 350 has a first ejector pin 351, a second ejector pin 352, a support plate 353, a support rod 354, a spring 355, a push-out plate 356, and a thrust bearing 357.

[0032] The first ejector pin 351 is a rod-shaped member that ejects the molding material that has hardened in the cavity Cv, i.e., the molded product, and releases it from the mold. The first ejector pin 351 is provided so as to penetrate through the movable mold 320 and reach the cavity Cv. The second ejector pin 352 is a rod-shaped member that ejects the molding material that has hardened in the runner Rn and releases it from the mold. The second ejector pin 352 is provided so as to penetrate through the movable mold 320 and reach the runner Rn.

[0033] The support plate 353 is a plate member that supports the first ejector pin 351 and the second ejector pin 352. The first ejector pin 351 and the second ejector pin 352 are fixed to the support plate 353. The support rod 354 is fixed to the support plate 353 and inserted into a through hole provided in the movable mold 320. The spring 355 is disposed in the space between the movable mold 320 and the support plate 353 and inserted into the support rod 354. During molding, the spring 355 biases the support plate 353 so that the tip of the first ejector pin 351 forms part of the wall surface of the cavity Cv and the tip of the second ejector pin 352 forms part of the wall surface of the runner Rn. The ejection plate 356 is fixed to the support plate 353. The thrust bearing 357 is attached to the push-out plate 356 and is provided so that the tip of the ball screw portion 240 does not damage the push-out plate 356 .

[0034] FIG. 5 is a perspective view showing a schematic configuration of the movable mold 320 in this embodiment. FIG. 6 is a first perspective view showing the configuration of the cutting mechanism 330 in this embodiment. FIG. 7 is a second perspective view showing the configuration of the cutting mechanism 330 in this embodiment. In order to facilitate understanding of the technology, FIGS. 6 and 7 show the movable mold 320 and the cutting mechanism 330 cut along line VI-VI in FIG. 5. In order to facilitate understanding of the technology, FIG. 7 shows the movable mold 320 with the insert portion 322 removed and the cutting mechanism 330 with the first elastic member 339 removed.

[0035] As shown in FIG. 5, the molding die 300 of this embodiment includes a cutting mechanism 330, a driving unit 340, and a rotation axis conversion unit 345 in addition to the fixed die 310, movable die 320, and ejection mechanism 350 described above.

[0036] Movable mold 320 includes a storage section 321, a nesting section 322, and a backing plate 323. Storage section 321 is provided with a recess for storing nesting section 322. Nesting section 322 is fixed within the recess of storage section 321. Nesting section 322 is provided with a recess that defines cavity Cv and a groove that defines runner Rn. Backing plate 323 supports storage section 321. Storage section 321 is provided with a refrigerant inlet 328 for introducing refrigerant supplied from refrigerant supply section 400, and a refrigerant outlet 329 for discharging the refrigerant introduced from refrigerant inlet 328.

[0037] As shown in Fig. 6, in this embodiment, eight cavities Cv and eight runners Rn are formed between the fixed mold 310 and the movable mold 320. The eight cavities Cv are arranged side by side in the circumferential direction. The eight runners Rn are arranged radially. In the following description, the ends of the runners Rn that are connected to the cavities Cv are referred to as gates Gt.

[0038] 6, in this embodiment, the cutting mechanism 330 is disposed in an internal space provided in the movable mold 320. In this embodiment, the cutting mechanism 330 has a rotary table 331, eight cutters 335, and a first elastic member 339.

[0039] The turntable 331 is disposed in the +X direction with respect to the nesting section 322. In this embodiment, the turntable 331 is configured in a circular plate shape centered on a central axis RX2. The turntable 331 is supported by a rotation axis conversion section 345 so as to be rotatable about the central axis RX2. In the following description, the central axis RX2 of the turntable 331 may be referred to as the rotation axis RX2 of the turntable 331. Note that in other embodiments, the turntable 331 may be configured in a regular octagonal plate shape, for example, rather than in a circular plate shape.

[0040] As shown in Fig. 7, the surface of the turntable 331 on the -X direction side is provided with an uneven surface 332 centered on the central axis RX2. The uneven surface 332 has eight convex portions 333 arranged in a row along the circumferential direction centered on the central axis RX2. When viewed from above and below, each of the convex portions 333 is arranged in the shape of a fan having an arc along the circumferential direction of the turntable 331. The portion of the uneven surface 332 excluding the eight convex portions 333 is flat. In the following description, the portion of the uneven surface 332 excluding the eight convex portions 333 will be referred to as a concave portion 334.

[0041] The eight cutters 335 are arranged in a line along the circumferential direction of the turntable 331. Each cutter 335 is disposed between the convex portions 333 of the turntable 331. Each cutter 335 is rod-shaped and arranged parallel to the central axis RX2 of the turntable 331. The tip 336 of each cutter 335 is configured as a sharp blade. As shown in FIG. 6 , the tip 336 is housed in a through-hole provided in the nesting portion 322. This through-hole has an opening on the inner wall surface of the gate Gt. To prevent the molding material from flowing in, the gap between the cutter 335 and the inner wall surface of the through-hole is preferably several micrometers to several hundred micrometers. The rear end 337 of each cutter 335 is bent toward the central axis RX2 of the turntable 331. The rear end 337 contacts the concave portion 334 of the turntable 331.

[0042] The first elastic member 339 is disposed between the central axis RX2 of the rotary table 331 and each cutter 335. An end of the first elastic member 339 on the −X direction side is in contact with the insert portion 322, and an end of the first elastic member 339 on the +X direction side is in contact with a rear end 337 of each cutter 335. The first elastic member 339 expands and contracts along the X direction from the fixed mold 310 toward the movable mold 320. The first elastic member 339 biases each cutter 335 toward the uneven surface 332 of the rotary table 331. In this embodiment, the first elastic member 339 is formed of a compression coil spring. Note that in other embodiments, the first elastic member 339 may be formed of rubber or an elastomer.

[0043] As shown in FIG. 5, the driving unit 340 is disposed in a direction perpendicular to the moving direction of the movable mold 320 relative to the movable mold 320. In this embodiment, the driving unit 340 is disposed in the -Z direction relative to the movable mold 320. The driving unit 340 is fixed to the movable mold 320 via a rotation axis conversion unit 345. The driving unit 340 generates a rotational driving force for rotating the rotary table 331. In this embodiment, the driving unit 340 is configured by a motor that is driven under the control of the control unit 500. The motor that constitutes the driving unit 340 is preferably a servo motor or a stepping motor that can control the rotational position of the output shaft. In this embodiment, the output shaft of the motor is disposed parallel to the Z direction.

[0044] The rotational axis conversion unit 345 is fitted into an opening that communicates with the internal space in which the cutting mechanism 330 is disposed. The rotational axis conversion unit 345 converts the direction of the rotational driving force generated by the drive unit 340 and transmits it to the rotary table 331. In this embodiment, the rotational axis conversion unit 345 is configured by an orthogonal axis type reducer. The input shaft of the reducer is arranged parallel to the Z direction and is connected to the output shaft of the motor that constitutes the drive unit 340. As shown in FIG. 6, the output shaft of the reducer is arranged parallel to the X direction and is connected to the surface of the rotary table 331 opposite to the uneven surface 332.

[0045] In this embodiment, the rotary table 331 rotates about the central axis RX2 due to the rotational driving force applied to the rotary table 331 from the drive unit 340 via the rotation axis conversion unit 345. The cutter 335 moves linearly along the central axis RX2 of the rotary table 331 in response to the rotational movement of the rotary table 331. Specifically, when the rotary table 331 rotates 22.5 degrees from the rotation position shown in FIG. 6, the protrusion 333 comes into contact with the rear end 337 of the cutter 335. The cutter 335 is pushed by the protrusion 333 and moves in the −X direction, so that the tip 336 of the cutter 335 protrudes into the gate Gt. When the rotary table 331 rotates another 22.5 degrees, the protrusion 333 moves between the cutters 335. Cutter 335 is pushed back by first elastic member 339 and moves in the +X direction, so that rear end 337 of cutter 335 comes into contact with recess 334 and tip 336 of cutter 335 is housed in the through-hole of nesting portion 322.

[0046] Fig. 8 is a flowchart showing the contents of the injection molding process. Figs. 9 to 13 are explanatory views showing the state of injection molding by the injection molding process. This process is started by the control unit 500 when, for example, the start button on the operation panel 30 provided on the base 20 is pressed.

[0047] As shown in Fig. 8, in the mold clamping process of step S110, control unit 500 controls mold drive unit 250 to bring movable mold 320 into contact with fixed mold 310, thereby clamping casting mold 300. As shown in Fig. 9, when movable mold 320 comes into contact with fixed mold 310, a runner Rn and a cavity Cv are defined between fixed mold 310 and movable mold 320.

[0048] In the injection process of step S120, the control unit 500 controls the plasticizing unit 110 to plasticize the molding material MT supplied from the hopper 101, and controls the injection control mechanism 120 to inject the plasticized molding material MT from the nozzle 130 into the molding die 300. As shown in FIG. 10 , during the injection process, the rear end 337 of the cutter 335 contacts the recess 334 of the rotary table 331, and the front end 336 of the cutter 335 is housed in the through-hole of the insert unit 322. Therefore, the cavity Cv is in communication with the runner Rn. The molding material MT injected from the nozzle 130 flows into the cavity Cv through the gate Gt, which is the end of the runner Rn.

[0049] In the cooling step of step S130, control unit 500 waits for a predetermined time until molding material MT in cavity Cv and runner Rn cools and hardens. Molding material MT in cavity Cv and runner Rn is cooled by the refrigerant supplied from refrigerant supply unit 400 to casting mold 300.

[0050] In the cutting process of step S140, the control unit 500 controls the drive unit 340 to cut the hardened molding material MT within the gate Gt with the tip 336 of the cutter 335. Specifically, the control unit 500 controls the drive unit 340 to rotate the turntable 331. As shown in FIG. 11 , the turntable 331 rotates 22.5 degrees, causing the protrusion 333 to contact the rear end 337 of the cutter 335. The cutter 335 is pushed in the −X direction by the protrusion 333, so that the tip 336 of the cutter 335 protrudes into the gate Gt and is pressed against the hardened molding material MT within the gate Gt. The molding material MT is cut by the pushing of the tip 336 of the cutter 335. As shown in FIG. 12 , the turntable 331 rotates another 22.5 degrees, causing the protrusion 333 to separate from the cutter 335. As the cutter 335 is pushed back in the +X direction by the first elastic member 339, the rear end 337 of the cutter 335 comes into contact with the recess 334, and the tip 336 of the cutter 335 moves away from the molding material MT. In this embodiment, the control unit 500 rotates the turntable 331 by 360 degrees or more to repeatedly press the tip 336 of the cutter 335 against the molding material MT to cut the molding material MT. Note that in other embodiments, the control unit 500 may rotate the turntable 331 by 45 degrees to press the tip 336 of the cutter 335 against the molding material MT once to cut the molding material MT.

[0051] In the mold opening process of step S150, as shown in FIG. 13, control unit 500 controls mold driving unit 250 to move movable mold 320 away from fixed mold 310, thereby placing casting mold 300 in a mold open state.

[0052] In the ejection step of step S160, the control unit 500 ejects and releases the molding material MT hardened in the cavity Cv (i.e., the molded product) and the molding material MT hardened in the runner Rn. As shown in FIG. 13 , in this embodiment, the first ejector pin 351 ejects into the cavity Cv as the movable mold 320 moves, and the second ejector pin 352 ejects into the sprue Sp as the movable mold 320 moves. The molding material MT hardened in the cavity Cv is ejected by the tip of the first ejector pin 351. The molding material MT hardened in the sprue Sp is ejected by the tip of the second ejector pin 352. In other words, in this embodiment, the mold opening step of step S150 and the ejection step of step S160 are performed simultaneously and in parallel. The control unit 500 then terminates this process. The ejected molded product is removed from the molding die 300 by, for example, a robot arm and placed on a pallet for transportation.

[0053] According to the injection molding apparatus 10 of this embodiment described above, after the molding material MT injected from the nozzle 130 into the mold 300 cools and hardens, the control unit 500 controls the drive unit 340 to cause the tip 336 of the cutter 335 of the cutting mechanism 330 to protrude into the gate Gt, thereby cutting the molding material MT inside the gate Gt. Therefore, the molding material MT can be cut at the intended position in the gate Gt.

[0054] Furthermore, in this embodiment, before opening the molding die 300, the control unit 500 causes the tip 336 of the cutter 335 to protrude into the gate Gt, so that the molding material MT can be cut by the tip 336 of the cutter 335 while being supported by the fixed die 310. This prevents the molding material from being pushed and moved by the tip 336 of the cutter 335, and allows the molding material MT to be cut more reliably.

[0055] Furthermore, in this embodiment, the tip 336 of the cutter 335 can be caused to protrude into the gate Gt by the rotational movement of the rotary table 331. Therefore, the molding material MT can be cut with a simple configuration.

[0056] Furthermore, in this embodiment, the cutting mechanism 330 is provided with a first elastic member 339 that urges the cutter 335 toward the uneven surface 332 of the turntable 331, so that the tip 336 of the cutter 335 that protrudes into the gate Gt can be returned to its original position by the first elastic member 339. Furthermore, by reciprocating the cutter 335, the tip 336 of the cutter 335 can be pressed against the molding material MT multiple times, so that the molding material MT can be cut more reliably.

[0057] In this embodiment, the injection unit 100 injects an elastomer as the molding material MT into the molding die 300. Because elastomers are stretchable, for example, when cutting the elastomer using a tunnel gate structure, the elastomer may stretch without being cut, resulting in the elastomer being torn off at a location other than the intended location. In contrast, in this embodiment, the tip 336 of the cutter 335 can be pressed against the elastomer, allowing the elastomer to be cut at the intended location. Furthermore, in this embodiment, the cutter 335 can be reciprocated by rotating the rotary table 331, allowing the elastomer to be cut more reliably.

[0058] Furthermore, in this embodiment, drive unit 340 and movable mold 320 are arranged side by side in a direction perpendicular to the direction of movement of movable mold 320. Therefore, forming mold 300 can be made smaller in size in the direction of movement of movable mold 320.

[0059] Furthermore, in this embodiment, the molding die 300 is provided with first ejector pins 351 that protrude into the cavity Cv in response to the movement of the movable die 320. Therefore, the molding material MT that has hardened in the cavity Cv can be easily released by the first ejector pins 351. Furthermore, in this embodiment, the molding die 300 is provided with second ejector pins 352 that protrude into the runner Rn in response to the movement of the movable die 320. Therefore, the molding material MT that has hardened in the runner Rn can be easily released by the second ejector pins 352.

[0060] B. Second embodiment: 14 is a perspective view showing the schematic configuration of a cutting mechanism 330b provided in a molding die 300b of an injection molding apparatus 10b according to the second embodiment. Injection molding apparatus 10b according to the second embodiment differs from the first embodiment in that a first ejector pin 351b that ejects a molded product is provided in cutting mechanism 330b. Unless otherwise specified, the other configurations are the same as those of injection molding apparatus 10 according to the first embodiment shown in FIG.

[0061] In the present embodiment, the cutting mechanism 330b includes a rotary table 331b, a cutter 335, a first ejector pin 351b, a first elastic member 339, and a second elastic member 359. On the uneven surface 332b of the rotary table 331b, a convex portion 333 and a concave portion 334 are provided on a circle centered on the central axis RX2 and overlapping with the cutter 335 when viewed in the +X direction, and the convex portion 333 and the concave portion 334 are provided on a circle centered on the central axis RX2 and overlapping with the first ejector pin 351b when viewed in the +X direction.

[0062] In this embodiment, the cutter 335 and the first ejector pin 351b are arranged side by side in the radial direction of the rotary table 331b. The first ejector pin 351b is arranged in the +X direction with respect to the cavity Cv. The first ejector pin 351b is biased toward the uneven surface 332b of the rotary table 331b by a second elastic member 359. In this embodiment, the second elastic member 359 is formed of a compression coil spring. The second elastic member 359 may also be formed of rubber or elastomer.

[0063] When the rotary table 331b rotates a predetermined angle from a state in which the rear end of the cutter 335 is in contact with the recess 334 and the rear end of the first ejector pin 351b is in contact with the recess 334, the rear end of the cutter 335 is pushed by the convex portion 333 of the uneven surface 332b, and the tip of the cutter 335 protrudes into the gate Gt. At this time, the rear end of the first ejector pin 351b is in contact with the recess 334 of the uneven surface 332b.

[0064] When the rotary table 331b further rotates by a predetermined angle from a state in which the tip of the cutter 335 protrudes into the gate Gt, the rear end of the first ejector pin 351b is pushed by the convex portion 333, causing the tip of the first ejector pin 351b to protrude into the cavity Cv. At this time, the rear end of the cutter 335 is in contact with the convex portion 333, and the tip of the cutter 335 protrudes into the gate Gt. Note that in another embodiment, the uneven surface 332b may be configured so that the rear end of the cutter 335 contacts the concave portion 334 when the convex portion 333 is in contact with the rear end of the first ejector pin 351b.

[0065] When the rotary table 331b further rotates a predetermined angle from the state in which the tip of the first ejector pin 351b protrudes into the cavity Cv, the cutter 335 is pushed back by the first elastic member 339 and comes into contact with the recess 334, and the first ejector pin 351b is pushed back by the second elastic member 359 and comes into contact with the recess 334.

[0066] According to the injection molding apparatus 10b of this embodiment described above, the tip of the first ejector pin 351b can be protruded into the cavity Cv by rotating the rotary table 331b, so that the molding material MT hardened in the cavity Cv can be easily released from the mold by the first ejector pin 351b.

[0067] C. Third embodiment: 15 and 16 are cross-sectional views showing the schematic configuration of a cutting mechanism 330c provided in a molding die 300c of an injection molding apparatus 10c according to the third embodiment. Injection molding apparatus 10c of the third embodiment differs from the first embodiment in that a valve portion 338 is provided at a tip portion 336 of a cutter 335c. Unless otherwise specified, the other configurations are the same as those of injection molding apparatus 10 of the first embodiment shown in FIG.

[0068] As shown in FIG. 15 , in this embodiment, the movable mold 320 has an exhaust passage Ep communicating with the runner Rn between the cutter 335c and the insert portion 322. The tip 336 of the cutter 335c is hook-shaped and has a valve portion 338. The valve portion 338 blocks the inflow of gas from the runner Rn to the exhaust passage Ep by contacting the insert portion 322. As shown in FIG. 16 , the valve portion 338 introduces gas from the runner Rn to the exhaust passage Ep by separating from the insert portion 322. The valve portion 338 opens and closes in response to the rotation of the rotary table 331. Specifically, when the cutter 335c is in contact with the recessed portion 334, the valve portion 338 closes the exhaust passage Ep, and when the cutter 335c is in contact with the protruding portion 333, the valve portion 338 opens the exhaust passage Ep.

[0069] When the molding material is plasticized in the plasticizing section 110, gas GS is generated from the molding material. Therefore, during the injection process, prior to the injection of the molding material from the nozzle 130, the gas GS flows from the nozzle 130 into the molding die 300c. If the gas GS remains in the cavity Cv, it may cause molding defects. Therefore, in this embodiment, during the injection process, the control section 500 opens the valve section 338 to discharge the gas GS that has flowed in from the nozzle 130 into the exhaust passage Ep. Thereafter, the control section 500 closes the valve section 338 before the molding material flows into the valve section 338.

[0070] According to injection molding apparatus 10c of the present embodiment described above, control unit 500 discharges gas GS from inside molding die 300c by opening valve unit 338. This makes it possible to prevent molding defects from occurring due to gas GS remaining inside cavity Cv.

[0071] D. Other Embodiments: (D1) In the injection molding apparatuses 10 to 10c of the above-described embodiments, the control unit 500 cuts the molding material MT by causing the tip portions 336 of the cutters 335, 335c to protrude into the gate Gt prior to the mold opening step. Alternatively, the control unit 500 may cut the molding material MT by causing the tip portions 336 of the cutters 335, 335c to protrude into the gate Gt after the mold opening step.

[0072] (D2) In the injection molding apparatuses 10 to 10c of the above-described embodiments, the cutting mechanisms 330 to 330c are configured to cause the cutters 335, 335c to move linearly along the central axis RX2 by rotating the turntables 331, 331b about the central axis RX2, thereby protruding them into the gate Gt. In contrast, the cutting mechanisms 330 to 330c may be configured to cause the turntables 331, 331b to move linearly along the central axis RX2, without rotating, thereby causing the cutters 335, 335c to move linearly along the central axis RX2.

[0073] (D3) In the injection molding apparatus 10 of the first embodiment described above, the cutting mechanism 330 is provided with a first elastic member 339 that urges the cutter 335 toward the rotary table 331. However, the first elastic member 339 that urges the cutter 335 toward the rotary table 331 does not have to be provided. In this case, for example, after the molded product is removed and before the next injection molding process is performed, the user may manually return the cutter 335 to its original position.

[0074] (D4) In the injection molding apparatus 10b of the second embodiment described above, the cutting mechanism 330b is provided with a first elastic member 339 that urges the cutter 335 toward the turntable 331b, and a second elastic member 359 that urges the first ejector pin 351b toward the turntable 331b. In contrast, at least one of the first elastic member 339 and the second elastic member 359 does not have to be provided in the injection molding apparatus 10b. In this case, for example, after the molded product is removed and before the next injection molding process is performed, the user may manually return the cutter 335 and the first ejector pin 351b to their original positions.

[0075] (D5) In the injection molding apparatuses 10 to 10c of the above-described embodiments, the drive unit 340 and the movable mold 320 are arranged side by side in the Z direction, which is a direction perpendicular to the X direction, which is the movement direction of the movable mold 320. In contrast, the drive unit 340 and the movable mold 320 may be arranged side by side in the Y direction. The drive unit 340 and the movable mold 320 may also be arranged side by side in the movement direction of the movable mold 320. For example, the drive unit 340 may be arranged in the +X direction relative to the movable mold 320.

[0076] (D6) In the injection molding apparatuses 10 to 10c of the above-described embodiments, the cutting mechanisms 330 to 330c are provided in the movable mold 320. However, the cutting mechanisms 330 to 330c may be provided in the fixed mold 310.

[0077] (D7) In the injection molding apparatuses 10 to 10c of the above-described embodiments, the cutting mechanisms 330 to 330c are configured so that the cutters 335, 335c protrude into the gate Gt. Alternatively, the cutting mechanisms 330 to 330c may be configured so that the cutters 335, 335c protrude into the portion of the runner Rn other than the gate Gt.

[0078] (D8) In the injection molding apparatuses 10 to 10c of the above-described embodiments, the injection section 100 injects a thermoplastic resin or a thermoplastic elastomer as the molding material into the cavity Cv. Alternatively, the injection section 100 may inject, for example, a thermosetting resin or a thermosetting elastomer as the molding material into the cavity Cv. In this case, in the injection molding apparatuses 10 to 10c, the injection section 100 injects the molding material that has been preheated by the plasticizing section 110 to exhibit fluidity into the cavity Cv, and the molding die 300 to 300c is provided with a heater that heats and hardens the molding material injected into the cavity Cv.

[0079] E. Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following forms. The technical features in the above embodiments corresponding to the technical features in each form described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0080] (1) According to a first aspect of the present disclosure, there is provided an injection molding apparatus. The injection molding apparatus includes: a molding die having a fixed die and a movable die facing the fixed die, the molding die including a cavity defined by the fixed die and the movable die and a runner communicating with the cavity; a clamping unit that moves the movable die relative to the fixed die; an injection unit that injects molding material into the cavity via the runner; a cutting mechanism provided in the molding die and having a cutter that protrudes into the runner; a drive unit that is provided in the molding die and drives the cutting mechanism; and a control unit that controls the injection unit, the clamping unit, and the drive unit. The control unit controls the injection unit to inject the molding material into the cavity, and then controls the drive unit to cause the cutter to protrude into the runner, thereby cutting the molding material that has hardened in the runner. According to this type of injection molding device, the hardened molding material is cut by projecting the cutter into the runner, so that the molding material can be cut at the desired position.

[0081] (2) In the injection molding apparatus of the above form, the control unit may control the injection unit to inject the molding material into the cavity, and then cut off the molding material that has hardened in the runner before controlling the clamping unit to open the molding mold. With this type of injection molding device, the cutter is pushed out into the runner before the mold is opened, which prevents the molding material from being pushed by the cutter and moving without being cut, thereby more reliably cutting the molding material.

[0082] (3) In the injection molding apparatus of the above form, the cutting mechanism comprises a rotary table having an uneven surface on which convex portions and concave portions are arranged alternately in a circumferential direction centered on the rotation axis, and the cutter arranged on the uneven surface, and the rotary table is rotated around the rotation axis by the drive unit, thereby pushing the cutter with the convex portions, and the cutter is pushed by the convex portions and moves linearly along the rotation axis, thereby protruding into the runner. According to this type of injection molding device, the cutter can be caused to protrude into the runner by the rotation of the rotary table, so that the molding material can be cut with a simple configuration.

[0083] (4) In the injection molding apparatus of the above aspect, the molding die may have an elastic member that biases the cutter toward the uneven surface. According to this type of injection molding apparatus, the cutter that protrudes into the runner can be returned to its original position by the elastic member.

[0084] (5) In the injection molding apparatus of the above form, the mold may have an exhaust passage communicating with the runner for discharging gas from within the mold, and a valve portion for opening and closing the exhaust passage may be provided at the tip of the cutter. In this injection molding apparatus, the valve is opened to allow gas flowing into the mold from the injection unit prior to the injection of molding material from the injection unit, thereby preventing molding defects caused by gas remaining in the mold.

[0085] (6) In the injection molding apparatus of the above form, the mold may have an ejector pin arranged on the uneven surface, and the rotary table may be rotated around the rotation axis by the drive unit, causing the convex portion to push the ejector pin, and the ejector pin may be pushed by the convex portion and move linearly along the rotation axis, thereby protruding into the cavity. According to this type of injection molding apparatus, the ejector pins are driven by the rotation of the rotary table, and the molding material that has hardened in the cavity can be extruded.

[0086] (7) In the injection molding apparatus of the above aspect, the molding die may have an ejector pin that projects into the cavity by linearly moving in response to the movement of the movable die by the mold clamping section. According to this type of injection molding apparatus, the ejector pins are driven by the movement of the movable mold, and the molding material that has hardened in the cavity can be pushed out.

[0087] (8) In the injection molding apparatus of the above aspect, the drive unit may be disposed in a direction perpendicular to the direction of movement of the movable mold relative to the movable mold. According to this type of injection molding apparatus, the molding die can be made smaller in size in the direction of movement of the movable die than in a type in which the molding die and the drive unit are arranged side by side in the direction of movement of the movable die.

[0088] (9) In the injection molding apparatus of the above aspect, the injection section may inject an elastomer as the molding material. According to this type of injection molding apparatus, the elastomer, which is easily torn off when using the tunnel gate method, can be cut by the cutter.

[0089] (10) According to a second aspect of the present disclosure, there is provided a molding die for an injection molding apparatus. The molding die for the injection molding apparatus includes a fixed die, a movable die that faces the fixed die and moves relative to the fixed die, a cutting mechanism having a cutter, and a drive unit that drives the cutting mechanism. The fixed die and the movable die define a cavity into which a molding material is injected, and at least one of the fixed die and the movable die is provided with a runner that communicates with the cavity. After the molding material is injected into the cavity through the runner, the cutting mechanism is driven by the drive unit to cause the runner to protrude the cutter, thereby cutting the molding material that has hardened within the runner. According to the molding die of the injection molding machine of this type, the hardened molding material is cut by projecting the cutter into the runner, so that the molding material can be cut at the desired position.

[0090] The present disclosure may be realized in various forms other than an injection molding apparatus, such as a molding die for an injection molding apparatus, a gate cutting apparatus, a gate cutting method, etc. [Explanation of symbols]

[0091] 10-10c... injection molding apparatus, 20... base, 30... operation panel, 100... injection section, 101... hopper, 110... plasticizing section, 120... injection control mechanism, 130... nozzle, 200... mold clamping section, 300... molding die, 310... fixed die, 320... movable die, 321... storage section, 322... nesting section, 323... receiving plate, 330... cutting mechanism, 331... rotary table, 332... recess Convex surface, 333...convex portion, 334...concave portion, 335...cutter, 336...tip portion, 337...rear end portion, 338...valve portion, 339...first elastic member, 340...drive portion, 345...rotation axis conversion portion, 347...rear end portion, 350...ejection mechanism, 351...first ejector pin, 352...second ejector pin, 359...second elastic member, 400...refrigerant supply portion, 500...control portion

Claims

1. 1. An injection molding apparatus comprising: a molding die having a fixed die and a movable die facing the fixed die, the molding die being provided with a cavity defined by the fixed die and the movable die and a runner communicating with the cavity; a mold clamping unit that moves the movable mold relative to the fixed mold; an injection unit that injects a molding material into the cavity through the runner; a cutting mechanism provided in the mold and having a cutter protruding into the runner; a drive unit provided in the mold for driving the cutting mechanism; a control unit that controls the injection unit, the mold clamping unit, and the drive unit; Equipped with the control unit controls the injection unit to inject the molding material into the cavity, and then controls the drive unit to cause the cutter to protrude into the runner before controlling the mold clamping unit to open the mold, thereby cutting the molding material that has hardened in the runner. Injection molding equipment.

2. 1. An injection molding apparatus comprising: a molding die having a fixed die and a movable die facing the fixed die, the molding die being provided with a cavity defined by the fixed die and the movable die and a runner communicating with the cavity; a mold clamping unit that moves the movable mold relative to the fixed mold; an injection unit that injects a molding material into the cavity through the runner; a cutting mechanism provided in the mold and having a cutter protruding into the runner; a drive unit provided in the mold for driving the cutting mechanism; a control unit that controls the injection unit, the mold clamping unit, and the drive unit; Equipped with the control unit controls the injection unit to inject the molding material into the cavity, and then controls the drive unit to cause the cutter to protrude into the runner, thereby cutting the molding material that has hardened in the runner; the cutting mechanism includes a rotary table having an uneven surface on which convex and concave portions are alternately arranged in a circumferential direction around a rotation axis, and the cutter is disposed on the uneven surface; the rotary table is rotated around the rotation axis by the drive unit, and the convex portion presses the cutter; the cutter is pushed by the convex portion and moves linearly along the rotation axis, thereby projecting into the runner; Injection molding equipment.

3. 3. The injection molding apparatus according to claim 2, The molding die has an elastic member that urges the cutter toward the uneven surface.

4. 4. The injection molding apparatus according to claim 2 or 3, the molding die has an exhaust passage that communicates with the runner and that exhausts gas from within the molding die; an injection molding apparatus, wherein a valve portion for opening and closing the exhaust passage is provided at a tip portion of the cutter;

5. 5. The injection molding apparatus according to claim 2, wherein the mold has an ejector pin disposed on the uneven surface, the rotary table is rotated around the rotation axis by the drive unit, and the convex portion pushes the ejector pin; The ejector pin is pushed by the convex portion and moves linearly along the rotation axis to protrude into the cavity.

6. 5. The injection molding apparatus according to claim 1, an injection molding apparatus, wherein the molding die has an ejector pin that protrudes into the cavity by linearly moving in response to the movement of the movable die by the mold clamping section;

7. 7. The injection molding apparatus according to claim 1, An injection molding apparatus, wherein the drive unit is disposed in a direction perpendicular to a moving direction of the movable mold relative to the movable mold.

8. 8. The injection molding apparatus according to claim 1, The injection unit is an injection molding device that injects an elastomer as the molding material.

9. A mold for an injection molding apparatus, Fixed type and a movable mold that faces the fixed mold and moves relative to the fixed mold; a cutting mechanism having a cutter; a drive unit that drives the cutting mechanism; Equipped with the fixed mold and the movable mold define a cavity into which a molding material is injected; At least one of the fixed mold and the movable mold is provided with a runner communicating with the cavity, the cutting mechanism is driven by the drive unit to cause the cutter to protrude into the runner after the molding material has been injected into the cavity through the runner and before the mold is opened, thereby cutting the molding material that has hardened within the runner; Molding mold.

10. A mold for an injection molding apparatus, Fixed type and a movable mold that faces the fixed mold and moves relative to the fixed mold; a cutting mechanism including a rotary table having an uneven surface on which convex portions and concave portions are alternately arranged in a circumferential direction around a rotation axis, and a cutter disposed on the uneven surface; a drive unit that drives the cutting mechanism; Equipped with the fixed mold and the movable mold define a cavity into which a molding material is injected; At least one of the fixed mold and the movable mold is provided with a runner communicating with the cavity, the cutting mechanism cuts the molding material that has hardened in the runner by causing the cutter to protrude from the runner after the molding material has been injected into the cavity through the runner; the rotary table is driven by the drive unit to rotate about the rotation axis, thereby pushing the cutter with the convex portion; the cutter is pushed by the convex portion and moves linearly along the rotation axis, thereby projecting into the runner; Molding mold.

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