Ejector pin, molding apparatus, and molding method

Abstract

To perform resin molding with easy maintenance and high productivity.SOLUTION: An ejector pin includes: a main body portion 14 having a columnar portion 12 inserted into an ejector pin hole 2he and a flange portion 13 formed on a root side of the columnar portion 12; and a protruding surface portion 11 in which a disk portion 111 connected to a tip portion of the columnar portion 12 to form a protruding surface 10fp and a fastening portion 112 extending from an opposite side of the protruding surface 10fp to form a detachable fastening mechanism with the tip portion are provided, and an inner portion in a radial direction is formed of a porous material that allows gas penetration in an axial direction. In the main body portion 14, a distribution hole 10h is formed in which one end is opened at a central portion in the radial direction of the tip portion and the other end is opened at a portion exposed from a movable mold 2 on the root side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present application relates to an ejector pin, a molding apparatus, and a molding method.

Background Art

[0002] In resin molding, when existing gas (atmosphere) in the mold or gas volatilized from the resin is not sufficiently discharged during resin filling, molding defects such as gas burns occur. In addition, the gas volatilized from the resin may be cooled on the way and deposited in the gas discharge path, sometimes blocking the gas discharge path. Therefore, regular maintenance of the gas discharge path is necessary, but the mold has to be disassembled and cleaned, and each time this requires a complicated process of stopping production, removing the mold, and disassembling and cleaning it.

[0003] In gas discharge, a porous material is provided in the path so that the resin is not discharged together with the gas (see, for example, Patent Document 1 and Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the porous material that prevents the resin from flowing out is likely to become clogged, and it is an essential part that requires regular replacement or maintenance such as cleaning. Therefore, every time clogging occurs, production must be stopped, and after removing the mold from the injection molding machine, it is necessary to disassemble the mold to take out the parts integrated with the porous material. At that time, since it is necessary to stop production for one to two days, the maintenance period becomes short, making it difficult to improve productivity.

[0007] This application discloses a technology for solving the above problems, and aims to perform resin molding that is easy to maintain and has high productivity.

Means for Solving the Problems

[0008] The ejector pin disclosed in this application has a main body portion having a columnar portion inserted into the ejector pin hole of the mold and a flange portion formed at the base side of the columnar portion, a disk portion that continues from the tip of the columnar portion to form a protruding surface, and a fastening portion that extends from the surface on the opposite side of the protruding surface of the disk portion and constitutes a detachable fastening mechanism with the tip portion. The protruding surface portion is formed of a porous material that allows gas to permeate through the inner portion in the radial direction in the axial direction. A circulation hole is formed in the main body portion, one end of which opens at the central portion in the radial direction of the tip portion, and the other end of which opens at the portion exposed from the mold on the base side. , the protruding surface portion is covered with a dense material formed denser than the porous material on the outer side in the radial direction of the porous material It is characterized by the above.

Effects of the Invention

[0009] According to the ejector pin, molding device, or molding method disclosed in this application, since the ejector pin is provided with a detachable and gas-permeable protruding surface portion, resin molding that is easy to maintain and has high productivity becomes possible.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0011] Embodiment 1. Figures 1 to 7 are for explaining the configuration of the ejector pin according to Embodiment 1, the configuration and operation of a molding apparatus using a mold in which the ejector pin is implemented, and the molding method. Figure 1 is a perspective view (Figure 1A) when the ejector pin is viewed from the protruding surface side, a cross-sectional view taken along the axis along line A-A of Figure 1A (Figure 1B), and an exploded view of the ejector pin corresponding to Figure 1A (Figure 1C). Figure 2 is a plan view when the movable mold in which the ejector pin is implemented is viewed from the cavity surface side, and Figure 3 is a schematic diagram showing the state in a molding apparatus having a gas control mechanism, including a cross-sectional view corresponding to line B-B of Figure 2 of the mold in which the ejector pin is implemented.

[0012] And, Figure 4A is a plan view when the protruding surface portion of the ejector pin is viewed from the protruding surface side, and Figure 4B is a cross-sectional view taken along line C-C of Figure 4A. Also, Figures 5A to 5C, and Figures 6A and 6B are schematic diagrams corresponding to Figure 3 showing the state for each process in the resin molding process executed by a molding apparatus equipped with a mold in which the ejector pin is implemented, and Figure 7 is a flowchart for explaining the operation in the resin molding process proceeding in the order of Figures 5A to 5C, Figure 6A, and Figure 6B.

[0013] Hereinafter, the configuration of the ejector pin according to Embodiment 1 of the present application, the configuration and operation of a molding apparatus using a mold in which the ejector pin is implemented, and the molding method will be described. Note that the same configuration is denoted by the same reference numeral, and the description thereof will not be repeated.

[0014] Before giving a detailed description of the ejector pins of the present application, the basic configuration of the molding die will be described. As shown in FIG. 3, the molding die 4 forms a space 4g by butting a fixed die 3 fixed to the fixed end 61 of the molding apparatus 100 and a movable die 2 supported by the drive end 62 having a drive mechanism and operating in the left-right direction in the drawing (when opening and closing the die). Then, for example, by injecting a resin material from a spool 4s provided in the fixed die 3 toward the space 4g, a resin product corresponding to the shape of the space can be molded.

[0015] And, as shown in FIG. 2, in the movable die 2, the same number of ejector pins 10 as the number of ejector pin holes 2he that are dispersed and arranged in the cavity surface 2fc facing the space 4g and penetrate in the depth direction are mounted. The ejector pin 10 has a flange portion 13 having a diameter larger than that of a rod-shaped portion (columnar portion 12) that can slide in the ejector pin hole 2he. The left and right positions of the ejector pin 10 (protrusion surface 10fp) are defined by sandwiching the flange portion 13 with an ejector plate 5 composed of a front plate 51 close to the movable die 2 and a rear plate 52 far from the movable die 2.

[0016] When the ejector plate 5 is driven to approach the movable die 2, the protrusion surface 10fp of the ejector pin 10 moves in the direction of protruding from the cavity surface 2fc, and when driven to move away, the protrusion surface 10fp can be moved in the direction of retracting. As will be described later, by protruding the ejector pin 10 from the cavity surface 2fc after mold opening, the molded resin product can be lifted from the cavity surface 2fc and easily taken out from the molding die 4. Note that the movable die 2 is provided with gas vents 2g for venting gas that communicate from the space 4g to the outside at a plurality of locations on the outer edge of the cavity surface 2fc.

[0017] The configuration up to this point is the same as that of a general mold for injection molding. On this premise, the characteristic parts of the ejector pin 10, the molding apparatus 100, and the molding method of the present application will be described. For the sake of simplicity, the description will be based on a two-plate mold base, but the same applies to a three-plate mold base.

[0018] Similar to a general ejector pin, the ejector pin 10 of the present application, as shown in FIG. 1A, has a flange portion 13 with a diameter larger than that of the columnar portion 12 provided at the base of the rod-shaped columnar portion 12 that slides within the ejector pin hole 2he for clamping by the ejector plate 5. As a characteristic configuration, as shown in FIG. 1B, a flow hole 10h penetrating the axial center is formed, and the protruding surface portion 11 forming the protruding surface 10fp is configured to have gas permeability and communicate with the flow hole 10h.

[0019] As a result, in the ejector pin 10, it becomes possible to circulate gas between the flange portion 13 and the protruding surface 10fp through the flow hole 10h. Although the flange portion 13 in which the flow hole 10h is formed and the columnar portion 12 are integrated to form the main body portion 14, as shown in FIG. 1C, a male screw 11sm corresponding to the female screw 12sf of the columnar portion 12 is formed on the protruding surface portion 11 and is detachable from the columnar portion 12.

[0020] As shown in FIG. 4B, the protruding surface portion 11 has, in terms of outer shape, the same outer diameter as the columnar portion 12, and is composed of a disk portion 111 forming the protruding surface 10fp and a fastening portion 112 that protrudes concentrically from the surface of the disk portion 111 opposite to the protruding surface 10fp and on which the male screw 11sm is formed. Further, in terms of material, the portion disposed on the axial center side has, for example, fine communication holes formed by sparsely bonding metal powders to allow gas to permeate in the axial direction, and becomes a porous portion 11p communicating with the flow hole 10h. On the other hand, the portion disposed on the outer peripheral side is a dense portion 11r that is denser and more rigid than the porous portion 11p. Such a configuration can be easily fabricated using, for example, a 3D metal printer.

[0021] In the disk portion 111, as shown in FIG. 4A, the diameter Dp of the porous portion 11p is 2 to 4 mm smaller than the diameter Db (FIG. 1B) of the columnar portion 12. When the porous portion 11p is formed with a mesh structure, the mesh interval is in the range of 20 to 70 μm. Further, the thickness tm of the disk portion 111 is 1.5 to 3.0 mm. The dense portion 11r is configured to cover the outer periphery of the porous portion 11p, and the outer diameter Dr in the disk portion 111 is 2 to 4 mm larger than the diameter Dp of the porous portion 11p.

[0022] For the male screw 11sm of the fastening portion 112, a metric screw having a number that is half of the diameter Db of the columnar portion 12 is used. For example, when φ10 (Db = 10 mm), it is fastened using an M5 screw. Regarding the fitting length of the screw, it conforms to JIS B209-2. The shaft center side of the male screw 11sm is continuous with the porous portion 11p of the disk portion 111, and the portion of the fastening portion 112 where the male screw 11sm is formed is formed densely in the same manner as the dense portion 11r of the disk portion 111.

[0023] As the steel material used for the columnar portion 12 and the flange portion 13, for example, die steel such as SKD61, high-speed steel such as SKH51, or mold steel such as SUS440 can be used. And the hole diameter Dh of the flow hole 10h is set to 1 / 4 of the diameter Db of the columnar portion 12. For example, if the columnar portion 12 is φ10, the hole diameter Dh of the flow hole 10h is φ2.5. Regarding the portion where the protruding surface portion 11 of the columnar portion 12 is mounted, a screw mechanism matching the screw size of the protruding surface portion 11 is provided for the fitting length conforming to JIS B209-2.

[0024] The columnar portion 12 and the flange portion 13 can be manufactured with the flow hole 10h using a 3D metal printer. Alternatively, after machining the outer shape by cutting, the flow hole 10h can be machined using a hole-making process such as electrical discharge machining or a ball mill, and the female thread 12sf can be machined by tapping. The flange portion 13 has an outer diameter 1.5 to 5.0 times that of the columnar portion 12. The thickness t13 of the flange portion 13 is set to be 4 mm or more and 6 mm or less. In any case, the flange portion 13 and the columnar portion 12 are made as part of the integrated main body portion 14 so as not to be affected by the attachment / detachment operation of the protruding surface portion 11, and are structured not to be joined by welding or screw fastening.

[0025] The molding device 100, which is an injection molding machine corresponding thereto, has a gas control mechanism 7 for controlling the flow of gas through the ejector pin 10 of the present application, as shown in FIG. 3, in addition to the mechanisms required for a general injection molding device. Then, piping for allowing the gas to flow in and out is provided for each flow hole 10h of the plurality of ejector pins 10 from the side of the flange portion 13.

[0026] Here, the ejector pin 10 is mounted in the molding die 4 in such a manner that the protruding surface portion 11 forming the protruding surface 10fp is disposed on the side in contact with the resin molded product 900 (FIG. 5B) molded within the space 4g. At this time, the ejector pin 10 is fixed in a manner of being sandwiched between the front plate 51 closer to the space 4g and the rear plate 52 farther from the space 4g. The front plate 51 is provided with a through hole (not shown) through which the columnar portion 12 passes but the flange portion 13 does not, similar to a general injection molding device. The clearance between the columnar portion 12 and the through hole is in the range of +0.2 to +1.0 mm.

[0027] On the other hand, the rear plate 52 is provided with a hole having the same diameter as the flow hole 10h of the main body portion 14 as a degassing hole (not shown) for allowing the gas discharged from the ejector pin 10 to flow in. A structure is provided in which an air coupler 75 to which an air tube 74 can be connected is attached to the surface on the back side with respect to the installation surface of the rear plate 52 with the flange portion 13. The air coupler 75 is assumed to be able to connect an air tube with a diameter of φ6 to φ10.

[0028] Then, the molding die 4 is divided into an upper surface portion and a lower surface portion starting from the central portion in the vertical direction (the vertical direction in FIG. 3) of the space 4g, for example. The air tubes 74 connected to the ejector pins 10 on the upper surface portion are unified into one flow path using an L-shaped or T-shaped connection coupler, and then branched into two flow paths by the valve 72 of the three-way valve. The air tube 74 can be switched by the valve 72 to connect to either the high-pressure flow path 73 side connected to the compressor 71 that compresses air or the atmosphere side.

[0029] The air tubes 74 connected to the ejector pins 10 on the lower surface portion are also unified into one flow path using an L-shaped or T-shaped connection coupler in the same manner as the upper surface portion, and then branched into two flow paths by the valve 72 of the three-way valve. The air tube 74 can be switched by the valve 72 to connect to either the high-pressure flow path 73 side connected to the compressor 71 or the atmosphere side.

[0030] The switching of the valve 72 is controlled by an output signal output from a control unit (not shown) of the molding apparatus 100 according to the progress of the molding process. Based on these configurations, the operation of the molding process by the molding apparatus 100 using the ejector pins 10, that is, the molding method, will be described with reference to the flowchart of FIG. 7.

[0031] In the filling step (step S100) of the resin 900C, as shown in FIG. 5A, the position (in the left-right direction in the figure) is adjusted so that the surface of the protruding surface portion 11 of the ejector pin 10 (the protruding surface 10fp) is on the same plane as the cavity surface 2fc of the molding die 4. Then, the resin 900C is filled into the space 4g through the sprue 4s. At this time, the valve 72 is switched to communicate with the atmosphere side in order to degas the air in the space 4g during the filling step.

[0032] When the filling is completed and the resin molded product 900 is formed by cooling and hardening, as shown in FIG. 5B, while keeping the position of the ejector pin 10 relative to the movable mold 2 fixed, the mold opening process is performed in which the movable mold 2 is moved in a direction to be separated from the fixed mold 3 (step S110). In the mold opening process, the valve 72 remains connected to the atmosphere.

[0033] When the mold opening is completed, as shown in FIG. 5C, the gas control mechanism 7 operates the valve 72 so as to switch the connection of the air tube 74 from the atmosphere side to the compressor 71 (compressor) side, and shifts to the vacuum breaking process (step S120). In the vacuum breaking process, the compressed air in the high-pressure flow path 73 sent out from the compressor 71 flows into the flow hole 10h through the valve 72 and the air tube 74. Then, air is ejected from the protruding surface 10fp through the porous portion 11p of the protruding surface portion 11.

[0034] Thereby, air is allowed to flow between the adhesion surface 900f of the resin molded product 900 with the cavity surface 2fc and the cavity surface 2fc, and a gap of 1 mm to 5 mm is generated between the adhesion surface 900f and the cavity surface 2fc to release the resin molded product 900. The pressure of the air used at this time is in the range of 0.3 MPa to 0.8 MPa, and it is adjusted according to the shape of the resin molded product 900, the mold release distance, etc.

[0035] Here, the time (mold release time) for the resin molded product 900 to be released from the cavity surface 2fc is measured, and the time to switch the valve 72 to the atmosphere side is determined from the measurement result. The same time as the measured mold release time and the protrusion start time are delayed. Alternatively, after the mold release time has elapsed, a method of sending a signal to the molding machine and shifting to the protrusion process may be used.

[0036] In the protrusion process (step S130), as shown in FIG. 6A, after switching the valve 72 to the atmosphere side, the ejector plate 5 is driven to protrude the protruding surface 10fp of the ejector pin 10 from the cavity surface 2fc. Thereby, the resin molded product 900 can be completely released from the molding die 4 (movable die 2) and taken out.

[0037] When the resin molded product 900 is taken out, the process proceeds to the cleaning step (step S200). In the cleaning step, as in the filling step, the ejector plate 5 is driven so that the protruding surface 10fp of the ejector pin 10 is on the same surface as the cavity surface 2fc, as shown in FIG. 6B. Then, the valve 72 is operated so that the connection destination of the air tube 74 is switched to the compressor 71 side.

[0038] Then, the compressed air in the high-pressure flow path 73 sent out from the compressor 71 passes through the valve 72, flows into the flow hole 10h through the air tube 74, passes through the porous portion 11p of the protruding surface portion 11, and jets out from the protruding surface 10fp. As a result, the gas generated from the resin and staying in the gas discharge path is discharged together with the compressed air, so that the gas discharge path can be cleaned. By performing this cleaning step for each molding shot, it becomes possible to discharge the staying gas, resin, etc. outside the molding die 4 before they adhere in the gas discharge path, preventing molding defects due to the deposition of gas and resin, and enabling a significant extension of the maintenance cycle.

[0039] Here, in the ejector pin 10 of the present application, by forming the flow hole 10h that penetrates up to the flange portion 13 on the opposite side of the protruding surface 10fp in the axial direction, the flow hole 10h opens outside the molding die 4 (movable die 2) instead of inside the ejector pin hole 2he. Therefore, even when the gas generated during molding is discharged by passing through the protruding surface portion 11, resin, etc. do not accumulate in the ejector pin hole 2he to hinder sliding.

[0040] Also, like the ejector pins in non-patent literature, simply making the protruding surface part gas-permeable can discharge the gas generated during molding, but it is difficult to discharge the gas, resin, etc. deposited in the gas discharge path. On the other hand, in the ejector pin 10 of the present application, the gas control mechanism 7 that can switch the connection target to either the atmosphere side or the compressor 71 side is connected to the flow hole 10h opened in the flange portion 13 on the opposite side of the protruding surface 10fp in the axial direction. Therefore, during the molding process, gas, resin, etc. before solidification can be discharged by gas pressure, and the maintenance cycle can be significantly extended.

[0041] Furthermore, in the molding process, if a vacuum breaking process (Fig. 5C: step S120) of ejecting gas from the protruding surface portion 11 to extrude the resin molded product 900 is executed, whitening and deformation of the molded product due to reduced mold release resistance during molded product removal can be suppressed, and the quality of the resin molded product 900 is improved.

[0042] Embodiment 2. In the above Embodiment 1, among the features of the ejector pin, a resin molding that utilizes the gas permeability of the protruding surface portion, is easy to demold, prevents molding defects due to gas and resin deposition, and enables a significant extension of the maintenance cycle was described. In this Embodiment 2, an operation example of further extending the maintenance cycle by utilizing the fact that the protruding surface portion is detachable will be described.

[0043] Figures 8 to 11 are for explaining the operation of a molding apparatus using a mold equipped with an ejector pin according to Embodiment 2. Figure 8 is a schematic diagram showing the state in a molding apparatus having a gas control mechanism corresponding to Figure 3 of Embodiment 1. Further, Figures 9A to 9C and Figures 10A to 10C are schematic diagrams corresponding to Figure 8 showing the state for each step in a maintenance process executed in a molding apparatus equipped with a mold equipped with an ejector pin, and Figure 11 is a flowchart for explaining the operation in the maintenance process proceeding in the order of Figures 10A to 10C, Figures 11A to 11C. Note that the configuration of the ejector pin and the molding apparatus is the same as that in Embodiment 1, the description of the same parts is omitted, and the respective figures used in Embodiment 1 are incorporated.

[0044] In carrying out the maintenance method according to Embodiment 2, as shown in Figure 8, with respect to Figure 3 of Embodiment 1, a spare 11S which is a spare part of the protruding surface portion 11 and a cleaning tank 80 for removing gas, resin, etc. deposited on the used protruding surface portion 11 are added. Based on these configurations, the maintenance process after the molding process by the molding apparatus 100 using the ejector pin 10 will be described with reference to the flowchart of Figure 11.

[0045] In the protruding process (Figure 6A: step S130) described in Embodiment 1, the resin molded product 900 is taken out. After the cleaning process (Figure 6B: step S200), with the mold 4 open, as shown in Figure 9A, the valve 72 is switched to connect to the atmosphere side to stop the molding process. Then, as a maintenance process, the ejector plate 5 is driven to cause the ejector pin 10 to perform an empty protrusion as shown in Figure 9B (step S300). Note that it is not limited to the above sequence. For example, without performing the cleaning process, the state where the resin molded product 900 is taken out in the protruding process may be replaced with step S300.

[0046] With the ejector pin 10 protruding, as shown in FIG. 9C, the protruding surface portion 11 of the ejector pin 10 is removed, and the removed protruding surface portion 11 is placed in the cleaning tank 80 and cleaned (step S310).

[0047] Next, as shown in FIG. 10A, the connection of the valve 72 is switched from the atmosphere side to the compressor 71 side. Then, the compressed air sent out from the compressor 71 is discharged to the outside through the air tube 74, the through hole of the rear plate 52, and the main body portion 14 (flow hole 10h) to clean the gas discharge path by air blow (step S320). Thereby, the gas discharge path is cleaned by discharging the resin-derived gas, tar, etc. remaining in the gas discharge path from the cavity surface 2fc of the molding die 4.

[0048] In addition, in the cleaning process of the gas discharge path, not limited to the supply of compressed air from the compressor 71, it may be configured to flow an organic solvent such as acetone or ethanol from a chemical liquid pump (not shown). At that time, in order to remove the flowed-in organic solvent, the valve 72 is switched to the compressor 71 side, and air is allowed to flow into the air tube 74, the through hole of the rear plate 52, and the main body portion 14 (flow hole 10h) to remove the remaining organic solvent.

[0049] After the cleaning process of the gas discharge path is completed and the air blow is stopped (step S330), as shown in FIG. 10B, the spare 11S of the protruding surface portion is fastened to the female screw 12sf of the columnar portion 12 to attach the spare 11S (step S340). Then, as shown in FIG. 10C, the ejector plate 5 is pulled back to retract the protrusion of the ejector pin 10 (step S350).

[0050] Here, since the gas-permeable protruding surface portion 11 where clogging is likely to occur is made detachable by screw fastening, in a state where the molding die 4 is attached to the molding apparatus 100, it is possible to easily replace the protruding surface portion 11 with the spare 11S simply by protruding the ejector pin 10. That is, since the replacement time due to clogging can be carried out in about 20 minutes, a significant improvement in productivity becomes possible. As a result, without removing the molding die 4 from the molding apparatus 100, the protruding surface portion 11 can be cleaned (replaced with a clean spare 11S), and the gas discharge path can be cleaned, so maintenance is facilitated and a significant reduction in maintenance time becomes possible.

[0051] Note that although exemplary embodiments are described in the present application, the various features, aspects, and functions described in the embodiments are not limited to the application of a specific embodiment, but can be applied to the embodiments alone or in various combinations. Therefore, an infinite number of variations not illustrated are assumed to be within the scope of the technology disclosed in the specification of the present application. For example, it is assumed to include cases where at least one component is deformed, added, or omitted.

[0052] For example, in each of the above embodiments, an example where the gas control mechanism 7 is provided as a part of the molding apparatus 100 is shown, but the present invention is not limited thereto. The gas control mechanism 7 may be a device separate from the molding apparatus 100, and may switch the valve 72 according to the molding process or adjust the timing of the molding process by transmitting and receiving signals via communication means or the like.

[0053] As described above, according to the ejector pin 10 of the present application, a main body portion 14 having a columnar portion 12 inserted into an ejector pin hole 2he of a mold (for example, a movable mold 2) and a flange portion 13 formed at the base side of the columnar portion 12, a disk portion 111 that is continuous with the tip of the columnar portion 12 to form a protruding surface 10fp, and a fastening portion 112 that forms a detachable fastening mechanism between the surface on the opposite side of the protruding surface 10fp of the disk portion 111 and a tip portion (for example, a female screw 12sf) are provided, and a protruding surface portion 11 formed of a porous material (porous portion 11p) that allows gas to permeate in the axial direction in the inner portion in the radial direction is provided. The main body portion 14 is configured such that a flow hole 10h is formed, one end of which opens at the central portion in the radial direction of the tip portion and the other end of which opens at a portion exposed from the mold (for example, the movable mold 2) on the base side. Therefore, without disassembling the molding die 4, it is possible to discharge resin-derived gas, tar, etc. remaining in the gas discharge path, facilitating maintenance and enabling a significant reduction in maintenance time.

[0054] If the fastening mechanism is configured by a male screw 11sm formed on the fastening portion 112 and a female screw 12sf formed at the opening portion of the tip of the flow hole 10h, the protruding surface portion 11 is mechanically and stably fixed to the main body portion 14, and by protruding the ejector pin 10 from the cavity surface 2fc, the protruding surface portion 11 can be easily replaced.

[0055] Furthermore, if the protruding surface portion 11 is configured such that the outer side in the radial direction of the porous material (porous portion 11p) is covered with a dense material (dense portion 11r) formed denser than the porous material (porous portion 11p), the reliability as a structural material increases, and in particular, both strong fastening and easy removal can be achieved.

[0056] Since the flow hole 10h is a through hole that passes through the axial center of the main body portion 14 and the other end opens at the flange portion 13, the machining is easy, and since there is no bent portion where tar or the like is likely to remain, the discharge is also easy.

[0057] In addition, according to the molding apparatus 100 that performs injection molding using the mold (molding die 4) in which the ejector pin 10 described above is implemented, depending on the process in injection molding, a compressed air supply system (compressor 71, high-pressure flow path 73), or a gas control mechanism 7 that can be switched and connected to the atmosphere is provided for the opening at the other end of the flow hole 10h. Therefore, maintenance is easy, and when vacuum breaking, the resin molded product 900 can be pushed out from the cavity surface 2fc by air pressure, so that whitening and deformation can be suppressed, and it becomes possible to stably manufacture a resin molded product 900 with high quality.

[0058] Furthermore, it is a molding method using the mold (molding die 4) in which the ejector pin described above is implemented. When resin filling into the mold (molding die 4) is completed and the mold is opened, compressed air is sent into the flow hole 10h and discharged from the protruding surface 10fp of the ejector pin 10, and a step (step S120) of forming a gap between the resin molded product 900 formed by resin filling and the mold (cavity surface 2fc) is included. In this way, the resin molded product 900 can be separated from the cavity surface 2fc by air pressure without relying on the protrusion of the ejector pin 10, so that whitening and deformation can be suppressed, and it becomes possible to stably manufacture a resin molded product 900 with high quality.

[0059] Furthermore, if it is configured to include a step (step S200, or step S320) of sending compressed air into the flow hole 10h and ejecting the compressed air from the protruding surface 10fp of the ejector pin 10 or the opening at the tip of the flow hole 10h after the resin molded product 900 is taken out from the mold (molding die 4), gas, resin-derived gas, tar, etc. remaining in the gas discharge path can be discharged. Therefore, maintenance is facilitated, and a significant reduction in maintenance time becomes possible.

Explanation of reference numerals

[0060] 2: Movable Mold, 2fc: Cavity Surface, 2g: Gas Vent, 2he: Ejector Pin Hole, 10: Ejector Pin, 10fp: Protruding Surface, 10h: Flow Hole, 11: Protruding Portion, 111: Disk Portion, 112: Fastening Portion, 11p: Porous Portion, 11r: Dense Portion, 11sm: Male Screw (Fastening Mechanism), 11S: Spare, 12: Columnar Portion, 12sf: Female Screw (Fastening Mechanism), 13: Flange Portion, 14: Main Body Portion, 5: Ejector Plate, 51: Front Plate, 52: Rear Plate, 7: Gas Control Mechanism, 71: Compressor, 72: Valve, 75: Air Coupler, 80: Cleaning Tank, 900: Resin Molded Product, Db: Diameter, Dr: Outer Diameter, Dp: Diameter, t13: Thickness, tm: Thickness.

Claims

1. A main body portion having a columnar portion inserted into an ejector pin hole of a mold and a flange portion formed at the base side of the columnar portion, and a disk portion that continues from the tip of the columnar portion to form a protruding surface, and a fastening portion that extends from the surface of the disk portion opposite to the protruding surface and constitutes a detachable fastening mechanism with the tip portion are provided, and a protruding surface portion formed of a porous material that allows gas to permeate axially in the inner portion in the radial direction, a circulation hole is formed in the main body portion, one end of which opens at the central portion in the radial direction of the tip portion and the other end of which opens at the portion exposed from the mold on the root side, The ejector pin is characterized in that the outer side in the radial direction of the porous material of the protruding surface portion is covered with a dense material formed more densely than the porous material.

2. The ejector pin according to claim 1, wherein the fastening mechanism is constituted by a male screw formed on the fastening portion and a female screw formed at the opening portion of the tip of the circulation hole.

3. The ejector pin according to claim 1 or 2, wherein the circulation hole is a through hole that passes through the axial center of the main body portion and the other end of which opens at the flange portion.

4. A molding apparatus for performing injection molding using a mold equipped with the ejector pin according to any one of claims 1 to 3, characterized in that a gas supply system for compressed air or a gas control mechanism capable of switching and connecting to the atmosphere is provided for the opening at the other end of the circulation hole according to the process in the injection molding.

5. An ejector pin having a main body portion having a columnar portion inserted into an ejector pin hole of a mold and a flange portion formed at the base side of the columnar portion, a disk portion that continues from the tip of the columnar portion to form a protruding surface, and a fastening portion that extends from the surface of the disk portion opposite to the protruding surface and constitutes a detachable fastening mechanism with the tip portion, and a protruding surface portion formed of a porous material that allows gas to permeate axially in the inner portion in the radial direction, and a circulation hole is formed in the main body portion, one end of which opens at the central portion in the radial direction of the tip portion and the other end of which opens at the portion exposed from the mold on the root side, or a molding method using a mold equipped with the ejector pin according to any one of claims 1 to 3, When resin filling into the mold is completed and the mold is opened, a step of sending compressed air into the flow hole to cause it to flow out from the protruding surface of the ejector pin and forming a gap between the resin molded product formed by the resin filling and the mold. A molding method characterized by including this.

6. After taking out the resin molded product from the mold, a step of sending compressed air into the flow hole and ejecting the compressed air from the protruding surface of the ejector pin or the opening at the tip of the flow hole. The molding method according to claim 5, characterized by including this.

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