Manufacturing apparatus and manufacturing method for molded products

Abstract

The present application relates to a manufacturing apparatus and a manufacturing method of a molded product. A manufacturing apparatus includes: an injection cylinder to which a molten resin is supplied and which is configured to inject the molten resin; and an injection plunger disposed such that the injection plunger fits in the injection cylinder and moves in a first direction and a second direction opposite to the first direction. The injection cylinder includes a base configured to accommodate the molten resin and a sleeve configured to be detachably mounted to the base. The injection plunger is configured to be inserted into an inside of the base via an opening portion formed in the sleeve and to slide on the sleeve.

Description

Technical Field

[0001] This invention relates to the manufacture of molded products. Background Technology

[0002] Generally, manufacturing equipment for producing molded resin products via injection molding is known. In such equipment, molten resin is injected into the cavity of a mold using a screw, plunger, etc.; the molten resin then cools and solidifies within the mold; and finally, after solidification, the mold is opened to remove the molded product. By repeating this series of operations from injecting molten resin to removing the molded product, molded products can be mass-produced. For example, pre-plasticized plunger injection molding machines and inline screw injection molding machines are known as manufacturing equipment for performing injection molding.

[0003] Japanese Patent Application Publication 2007-261055 discloses a pre-plasticized plunger injection molding machine. The pre-plasticized plunger injection molding machine includes: a plasticizing section comprising a plasticizing screw; an injection cylinder for storing plasticized and molten resin; an injection plunger for injecting the molten resin stored in the injection cylinder; and a drive mechanism for driving the injection plunger. The injection plunger is driven by the drive mechanism to move forward and backward.

[0004] However, in processes such as metering or unloading, conventional injection molding machines use a drive mechanism to force the injection plunger to retract. If the drive mechanism forces the injection plunger to retract, the pressure in the molten resin contained in the injection cylinder changes rapidly, causing air to be drawn into the molten resin. If the molded product is manufactured with air drawn into the molten resin, molding defects such as voids or silver streaks will appear. Summary of the Invention

[0005] According to a first aspect of the invention, a manufacturing apparatus includes: an injection cylinder to which molten resin is supplied and configured to inject the molten resin; and an injection plunger configured such that the injection plunger engages within the injection cylinder and is movable in a first direction and a second direction opposite to the first direction. The injection cylinder includes a matrix configured to contain the molten resin and a sleeve configured to be detachably mounted to the matrix. The injection plunger is configured to be inserted into the interior of the matrix via an opening formed in the sleeve and to slide on the sleeve.

[0006] According to a second aspect of the invention, a manufacturing apparatus includes: an injection cylinder to which molten resin is supplied and configured to inject the molten resin; an injection plunger configured such that the injection plunger engages within the injection cylinder and is movable in a first direction and a second direction opposite to the first direction; a pressing member configured to be detachable from the injection plunger and to press the injection plunger to move it toward the first direction; and a sensor configured to detect contact and / or separation between the injection plunger and the pressing member.

[0007] According to a third aspect of the invention, a manufacturing apparatus includes: an injection cylinder to which molten resin is supplied, and the injection cylinder is configured to inject the molten resin; an injection plunger configured to engage in the injection cylinder and move in a first direction and a second direction opposite to the first direction; a pressing member configured to be detachable from the injection plunger and to press the injection plunger to move the injection plunger toward the first direction; a drive source configured to drive the pressing member along the first and second directions; and a control unit configured to control the drive source. In the state where the pressing member is detached from the injection plunger, the injection plunger is moved toward the second direction by pressing it with molten resin supplied to the injection cylinder. The control unit is configured to: control the drive source to move the pressing member to a first position while metering the molten resin supplied to the injection cylinder; and control the drive source to inject molten resin after retracting the pressing member to a second position retracted from the first position.

[0008] According to a fourth aspect of the invention, a manufacturing apparatus includes: an injection cylinder to which molten resin is supplied, and the injection cylinder is configured to inject the molten resin; an injection plunger configured such that the injection plunger engages within the injection cylinder and moves in a first direction and a second direction opposite to the first direction; a drive source configured to drive the injection plunger; and a control unit configured to control the drive source. The control unit is configured to drive the drive source to move the injection plunger toward the first direction when molten resin is injected from the injection cylinder. The control unit is configured to stop the drive source to allow the injection plunger to move toward the second direction when molten resin is supplied to the injection cylinder or when the supply of molten resin to the injection cylinder is complete.

[0009] Other features of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic cross-sectional view of the manufacturing equipment of the first embodiment.

[0011] Figure 2 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the first embodiment.

[0012] Figure 3This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the first embodiment.

[0013] Figure 4 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the first embodiment.

[0014] Figure 5 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the first embodiment.

[0015] Figure 6 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the second embodiment.

[0016] Figure 7 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the second embodiment.

[0017] Figure 8 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the second embodiment.

[0018] Figure 9 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the second embodiment.

[0019] Figure 10 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the third embodiment.

[0020] Figure 11 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the third embodiment.

[0021] Figure 12 This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment of the third embodiment.

[0022] Figure 13A It is a schematic cross-sectional view of the injection cylinder, injection plunger, and pressing component of the first variant of the manufacturing equipment.

[0023] Figure 13B This is a schematic cross-sectional view of the injection cylinder, injection plunger, and pressing component of the second variant of the manufacturing equipment.

[0024] Figure 13C This is a schematic cross-sectional view of the injection cylinder, injection plunger, and pressing member of the manufacturing equipment according to the fourth embodiment.

[0025] Figure 14 This is a diagram showing a portion of the manufacturing apparatus according to the fourth embodiment.

[0026] Figure 15A This is a diagram showing a portion of the manufacturing apparatus according to the fourth embodiment.

[0027] Figure 15B This is a diagram showing a portion of the manufacturing apparatus according to the fourth embodiment.

[0028] Figure 16 This is a schematic cross-sectional view of the manufacturing equipment of the fifth embodiment. Detailed Implementation

[0029] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0030] First Embodiment

[0031] Figure 1 This is a schematic cross-sectional view of the manufacturing apparatus 100 according to the first embodiment. The manufacturing apparatus 100 is a pre-plasticized plunger injection molding apparatus and is used to manufacture molded products made of resin. The manufacturing apparatus 100 includes a plasticizing section 111, an injection section 112, a connecting unit 113, and a control device 200. The connecting unit 113 is an example of a connecting portion that connects the plasticizing section 111 and the injection section 112. The control device 200 is an example of a control unit. For example, the control device 200 is one or more computers, each computer including a processor. The control device 200 can control the components included in the plasticizing section 111 and the injection section 112.

[0032] The plasticizing section 111 plasticizes the resin material placed in it and supplies the resin material to the injection section 112 via the connecting unit 113. The injection section 112 supplies molten resin into the mold 10 by injecting the molten resin supplied from the plasticizing section 111 into the mold 10. Within the mold 10, the cavity CV is defined by closing the mold 10. The cavity CV is a space whose shape corresponds to the shape of the corresponding molded product. The injection section 112 fills the cavity CV with molten resin via the runner by injecting molten resin into the cavity CV.

[0033] The plasticizing unit 111 includes a hopper (not shown), a plasticizing cylinder 121, a plasticizing screw 122, and a plasticizing drive unit 123. For example, granular resin material is fed into the hopper (not shown). The resin material is a thermoplastic resin. The temperature of the plasticizing cylinder 121 is adjusted to the temperature at which the supplied resin material is plasticized by heating the plasticizing cylinder 121 with a heater (not shown). The plasticizing screw 122 is disposed inside the interior 126 of the plasticizing cylinder 121. The plasticizing screw 122 is a rotatable screw. For example, the diameter of the plasticizing screw 122 is 20 mm.

[0034] The plasticizing drive unit 123 includes a drive source (e.g., a motor) and rotates the plasticizing screw 122. The drive source of the plasticizing drive unit 123 is controlled by the control device 200. When the plasticizing screw 122 is rotated by the plasticizing drive unit 123, the plasticizing screw 122 moves the resin material supplied from the hopper (not shown) to the front end of the plasticizing screw 122 while plasticizing the resin material.

[0035] The injection unit 112 includes an injection cylinder 141, an injection plunger 142, a switching valve 143, and an injection drive unit 144. Preferably, both the injection cylinder 141 and the injection plunger 142 are made of metal. Preferably, the metal is, for example, high-speed steel or hard alloy.

[0036] The injection cylinder 141 includes a supply inlet S for supplying molten resin and a nozzle N for discharging molten resin. The nozzle N is an example of an injection outlet. In a first embodiment, the nozzle N is located at the front end of the injection cylinder 141 along the axis C1 of the injection cylinder 141. By contacting the nozzle N with the mold 10, the interior 146 of the injection cylinder 141 and the cavity CV of the mold 10 are in communication with each other.

[0037] The plasticizing cylinder 121 and the injection cylinder 141 are connected to each other via a connecting unit 113. The connecting unit 113 includes a check valve 131 connected to the supply inlet S. The check valve 131 is a valve used to prevent molten resin from flowing back from the supply inlet S to the outside of the injection cylinder 141 (i.e., to the plasticizing section 111). In other words, the check valve 131 is a valve used to prevent molten resin from flowing from the supply inlet S to the outside of the injection cylinder 141. The interior 126 of the plasticizing cylinder 121 and the interior 146 of the injection cylinder 141 are connected to each other via a flow path PT1, in which the check valve 131 is disposed. The connecting unit 113 includes components 132 and 133 for defining the flow path PT1. The check valve 131 is disposed inside components 132 and 133. The check valve 131 includes a ball 11, a valve seat 51, and a valve claw 52. The valve seat 51 is disposed on the resin inflow side, and the valve claw 52 is disposed on the resin outflow side. For example, the diameter of ball 11 is 8mm.

[0038] Check valve 131 is connected to the supply inlet S and oriented such that molten resin does not flow back from injection cylinder 141 to plasticizing screw 122. Because check valve 131 is connected to the supply inlet S, molten resin flows in the flow path PT1 in the forward direction from plasticizing cylinder 121 to injection cylinder 141, but not in the reverse direction from injection cylinder 141 to plasticizing cylinder 121. Flow path PT1 is the flow path through which the molten resin flows. Resin that has been melted and plasticized by plasticizing screw 122 is supplied to the interior 146 of injection cylinder 141 via check valve 131 and the supply inlet S of injection cylinder 141. In this way, molten resin supplied from plasticizing screw 122 can be stored in the interior 146 of injection cylinder 141. Note that a switching valve can also be provided at the supply inlet S instead of check valve 131.

[0039] Inside the injection cylinder 141, 146, a switching valve 143 is disposed near the nozzle N. The switching valve 143 is switchable between a position allowing molten resin to be injected from the nozzle N (open position) and a position preventing molten resin from being injected from the nozzle N (closed position). That is, the switching valve 143 is a valve that prevents molten resin from flowing from the nozzle (injection outlet) N to the outside of the injection cylinder 141. The switching valve 143 is controlled by the control device 200. The injection cylinder 141 includes an inner circumferential surface 147 defining an internal space. An injection plunger 142 is configured to engage within the injection cylinder 141 such that the injection plunger 142 can move relative to the injection cylinder 141 in the Z direction (i.e., the direction of axis C1).

[0040] The injection drive unit 144 includes a motor 151, a transmission mechanism 152, and a pressing member 153. The motor 151 is an example of a drive source. Preferably, the pressing member 153 is made of metal. The motor 151 may be a rotary motor and is controlled by a control device 200. The transmission mechanism 152 is a mechanism that transmits the driving force of the motor 151 to the pressing member 153. For example, the transmission mechanism 152 includes a linear motion mechanism. The transmission mechanism 152 may also include a timing belt. The linear motion mechanism is a mechanism that converts rotary motion into linear motion and may include a ball screw and a nut. The linear motion mechanism includes a linear motion member 154 that moves linearly in the Z direction. The pressing member 153 is connected to the linear motion member 154. Therefore, in the first embodiment, the motor 151 can drive the pressing member 153 in the Z direction via the transmission mechanism 152, causing the pressing member 153 to move linearly in the Z direction. The pressing member 153 is a component distinct from and separate from the injection plunger 142. Therefore, the pressing member 153 can contact or separate from the injection plunger 142.

[0041] Note that the Z1 direction in the Z-direction is defined as the direction in which each of the injection plunger 142 and the pressing member 153 approaches the nozzle N along the axis C1. That is, the Z1 direction is defined as the direction in which the molten resin stored in the injection cylinder 141 is injected from the nozzle N of the injection cylinder 141 into the cavity CV. Furthermore, the Z2 direction in the Z-direction is defined as the direction in which each of the injection plunger 142 and the pressing member 153 moves away from the nozzle N along the axis C1. The Z2 direction is the opposite of the Z1 direction. Moreover, the movement of each of the injection plunger 142 and the pressing member 153 along the Z1 direction is defined as forward movement, and the movement of each of the injection plunger 142 and the pressing member 153 along the Z2 direction is defined as backward movement. The Z1 direction is an example of a first direction, and the Z2 direction is an example of a second direction. Each of the injection plunger 142 and the pressing member 153 can move along both the Z1 and Z2 directions.

[0042] The pressing member 153 is driven by the motor 151 and moves along the Z direction, thereby allowing the pressing member 153 to contact or separate from the injection plunger 142. Specifically, the pressing member 153 is driven by the motor 151 and moves along the Z1 direction, allowing it to press the injection plunger 142 in the Z1 direction, causing the injection plunger 142 in contact with the pressing member 153 to move in the Z1 direction. Furthermore, the pressing member 153 is driven by the motor 151 and moves in the Z2 direction, allowing it to separate from the injection plunger 142. In other words, the Z1 direction is the direction in which the pressing member 153 can press the injection plunger 142, and the Z2 direction is the direction in which the pressing member 153 can separate from the injection plunger 142.

[0043] The interior 146 of the injection cylinder 141 includes portions 148 and 149. Portion 148 is the portion where the injection plunger 142 can slide in the Z direction. Portion 149 is the portion located on the Z1 direction side relative to portion 148. Each of portions 148 and 149 is a generally cylindrical space. Portions 148 and 149 are in communication with each other. The diameter of portion 148 is larger than the diameter of portion 149. That is, the injection plunger 142 can move in the Z direction within portion 148, but when it abuts against the abutment surface 150, which is a step formed between portions 148 and 149 in the injection cylinder 141, movement in the Z1 direction is prevented. Therefore, the injection plunger 142 can move in the Z direction within the space between the pressing member 153 and the abutment surface 150. However, when it comes into contact with the pressing member 153, the injection plunger 142 is prevented from moving past the pressing member 153 in the Z2 direction; when it comes into contact with the contact surface 150, the injection plunger 142 is prevented from moving past the contact surface 150 in the Z1 direction.

[0044] Both the supply inlet S and the nozzle N are connected to section 149. In section 149, a switching valve 143 is disposed between the supply inlet S and the nozzle N. The switching valve 143 is an on / off valve. When the switching valve 143 is switched and positioned in the closed position, the molten resin that has flowed from the plasticizing cylinder 121 through the flow path PT1 to the supply inlet S is supplied from the supply inlet S to section 149, and then from section 149 to section 148.

[0045] After molten resin is supplied to injection cylinder 141, switching valve 143 switches to the open position. With switching valve 143 switched and positioned in the open position, injection plunger 142 moves forward in the Z1 direction at a predetermined speed, thereby injecting molten resin from nozzle N. When molten resin is injected from nozzle N, check valve 131 reduces the amount of molten resin flowing back from injection cylinder 141 to plasticizing cylinder 121. The molten resin injected from nozzle N fills the cavity CV, which communicates with nozzle N.

[0046] The pressing member 153 is a shaft-shaped member extending in the Z direction. For example, the diameter of the pressing member 153 is 10 mm. The Z direction is equal to the longitudinal direction of the pressing member 153. The rear end of the interior 146 of the injection cylinder 141 is open in the Z1 direction. The pressing member 153 is inserted into the injection cylinder 141 through the opening, such that the front end 1531 of the pressing member 153 in the Z1 direction is located in the interior 146 of the injection cylinder 141. The front end 1531 of the pressing member 153 in the Z1 direction is the first part facing the injection plunger 142. The rear end 1532 of the pressing member 153 in the Z1 direction is connected to the linear motion member 154.

[0047] The injection plunger 142 is a generally cylindrical component. The injection plunger 142 includes a rear end portion 1422 and a front end portion 1421. The rear end portion 1422 is formed at the rear end of the injection plunger 142 in the Z1 direction and contacts the front end portion 1531 of the pressing member 153. The front end portion 1421 is formed at the front end of the injection plunger 142 in the Z1 direction and contacts the molten resin injected into the injection cylinder 141. The rear end portion 1422 is an example of a second portion facing the pressing member 153. The rear end portion 1422 is the portion opposite to the front end portion 1421 in the Z direction. At least the front end portion 1421 of the injection plunger 142 is located within the interior 146 of the injection cylinder 141. In a first embodiment, the entire injection plunger 142 is located within the interior 146 of the injection cylinder 141.

[0048] Preferably, at least one of the front end portion 1531 and the rear end portion 1422 is spherical. Therefore, the pressing member 153 and the injection plunger 142 are in point contact with each other. In a first embodiment, the front end portion 1531 is spherical and the rear end portion 1422 is flat. Note that the rear end portion 1422 may be spherical and the front end portion 1531 may be flat. In another case, both the rear end portion 1422 and the front end portion 1531 may be spherical.

[0049] The injection plunger 142 mates with (or contacts) the inner circumferential surface 147, allowing it to slide in the Z-direction within the interior 146 of the injection cylinder 141. The inner diameter φ1 of the injection cylinder 141 is larger than the diameter φ2 of the portion of the injection plunger 142 that mates with it within the injection cylinder 141. Preferably, the difference (φ1-φ2) between the inner diameter φ1 of the injection cylinder 141 and the diameter φ2 of the injection plunger 142 is equal to or greater than 2 μm and equal to or less than 50 μm. In the first embodiment, the inner diameter φ1 of the injection cylinder 141 is equal to the diameter of the portion 148 of the interior 146. Because the difference (φ1-φ2) is equal to or greater than 2 μm and equal to or less than 50 μm, resin leakage from the gap between the injection cylinder 141 and the injection plunger 142 can be effectively reduced. Furthermore, the possibility of the injection plunger 142 being stuck by the inner circumferential surface 147 of the injection cylinder 141 (i.e., being jammed) can be effectively reduced.

[0050] For example, if the injection plunger 142 is a cylindrical component with a diameter φ2 of 12 mm and a height of 15 mm, and the inner diameter φ1 of the injection cylinder 141 is 12.01 mm, then the difference between the inner diameter φ1 and the diameter φ2 (φ1-φ2) is 0.01 mm.

[0051] The diameter of the pressing member 153 is made smaller than the diameter of the injection plunger 142 so that the pressing member 153 does not contact the inner circumferential surface 147 of the injection cylinder 141. Therefore, the pressing member 153 does not contact the injection cylinder 141. That is, the pressing member 153 is separated from the injection cylinder 141.

[0052] In the first embodiment, the manufacturing apparatus 100 further includes a sensor 155. The sensor 155 is used to detect whether the injection plunger 142 contacts or separates from the pressing member 153. For example, the sensor 155 is a strain gauge disposed on the pressing member 153. By using the value detected by the sensor 155, the control device 200 can determine whether the injection plunger 142 contacts the pressing member 153. Note that the sensor 155 can be any sensor, as long as it can detect contact between the injection plunger 142 and the pressing member 153. That is, the sensor 155 only needs to be a sensor capable of detecting contact and / or separation between the injection plunger 142 and the pressing member 153.

[0053] Sensor 155 is not limited to mechanical sensors such as strain gauges. For example, sensor 155 can be an electromagnetic sensor or an optical sensor.

[0054] Sensor 155, acting as an electromagnetic sensor, can detect changes in capacitance or magnetic field corresponding to the distance between the injection plunger 142 and the pressing member 153. When sensor 155 is positioned near the injection cylinder 141, it is susceptible to heat from the injection cylinder 141 (or its accuracy may decrease). Considering this, it is preferable to provide a heat-insulating member between the injection cylinder 141 and sensor 155. The heat-insulating member can be made of glass fiber bonded together with an organic adhesive (e.g., polyester) or an inorganic adhesive (e.g., a silicone compound). Preferably, the heat-insulating member is made of glass fiber bonded together with a silicone compound adhesive to ensure heat resistance (e.g., above 200°C). Sensor 155, acting as an electromagnetic sensor, can also be a sensor that detects the torque of the drive source used to drive the pressing member 153. In this case, if motor 151 is a servo motor, sensor 155 can be a sensor that detects the servo motor current value as a measure of the distance between the injection plunger 142 and the pressing member 153.

[0055] Sensor 155, serving as an optical sensor, may include a light-emitting portion and a light-receiving portion. The light-emitting portion emits light toward the contact portion (and its surroundings) between the injection plunger 142 and the pressing member 153. In a first example where the optical sensor detects contact and / or separation between the injection plunger 142 and the pressing member 153, the light-emitting portion and the light-receiving portion of sensor 155 are disposed on the same side relative to the contact portion between the injection plunger 142 and the pressing member 153. A portion of the light emitted from the light-emitting portion of sensor 155 toward the contact portion (and its surroundings) between the injection plunger 142 and the pressing member 153 is reflected from the injection plunger 142 or the pressing member 153 and detected by the light-receiving portion of sensor 155. When the injection plunger 142 and the pressing member 153 separate from each other, a gap is created between the injection plunger 142 and the pressing member 153. Therefore, at least a portion of the light emitted from the light-emitting portion passes through this gap. Since a portion of the light is not reflected by the injection plunger 142 or the pressing member 153, this portion of the light does not reach the light receiving section of the sensor 155. Based on this principle, if the amount of light received by the light receiving section of the sensor 155 is relatively large, the injection plunger 142 and the pressing member 153 will be in contact with each other. Therefore, this principle can be used to detect the contact between the injection plunger 142 and the pressing member 153. If the amount of light received by the light receiving section of the sensor 155 is relatively small, separation between the injection plunger 142 and the pressing member 153 can be detected. Note that although reflected light from the injection plunger 142 and / or the pressing member 153 has been described in this embodiment, the reflector does not necessarily have to be the injection plunger 142 and / or the pressing member 153 themselves. For example, the reflector can be a reflecting member that moves together with the injection plunger 142 and / or the pressing member 153.

[0056] In a second example where contact and / or separation between the injection plunger 142 and the pressing member 153 is detected by an optical sensor, the light-emitting portion and the light-receiving portion of the sensor 155 are arranged opposite to each other relative to the contact portion between the injection plunger 142 and the pressing member 153. A portion of the light emitted from the light-emitting portion of the sensor 155 toward the contact portion (and its surroundings) between the injection plunger 142 and the pressing member 153 passes through the gap between the injection plunger 142 and the pressing member 153 and is received by the light-receiving portion of the sensor 155. When the injection plunger 142 and the pressing member 153 separate from each other, a gap is created between the injection plunger 142 and the pressing member 153. Therefore, at least a portion of the light emitted from the light-emitting portion passes through this gap and reaches the light-receiving portion of the sensor 155. When the injection plunger 142 and the pressing member 153 come into contact with each other, a small gap or no gap is created between the injection plunger 142 and the pressing member 153. Therefore, at least a portion of the light emitted from the light-emitting portion does not reach the light-receiving portion of the sensor 155. Based on this principle, if the amount of light received by the light receiver of sensor 155 is relatively large, the injection plunger 142 and the pressing member 153 will separate from each other. Therefore, this principle can be used to detect the separation between the injection plunger 142 and the pressing member 153. If the amount of light received by the light receiver of sensor 155 is relatively small, the contact between the injection plunger 142 and the pressing member 153 can be detected.

[0057] In either the first or second example of detecting contact and / or separation between the injection plunger 142 and the pressing member 153 using an optical sensor, the light-emitting portion and the light-receiving portion can both be configured to move together with one of the injection plunger 142 and the pressing member 153. In another example, one of the light-emitting portion and the light-receiving portion can be configured to move together with one of the injection plunger 142 and the pressing member 153, while the other of the light-emitting portion and the light-receiving portion can be configured to move together with the other of the injection plunger 142 and the pressing member 153. In yet another example, one of the light-emitting portion and the light-receiving portion can be located on a structure that does not move together with either the injection plunger 142 or the pressing member 153. Instead of the light-emitting portion, natural light generated in the installation environment of the manufacturing equipment 100 or light from a lighting device can be used. If the sensor 155 uses modulated pulsed light, the sensor 155 can reliably detect contact and / or separation while reducing the effects of interfering light (e.g., natural light generated in the installation environment of the manufacturing equipment 100 or light from a lighting device).

[0058] Considering the installation space of the sensor 155 and the effect of heat from the injection cylinder 141 and the injection plunger 142 on the sensor 155 (reduced accuracy), it is preferable to fix the sensor 155, whose light-emitting part and light-receiving part are integrated with each other, to the pressing member 153. In this case, the light-emitting part of the optical sensor 155 fixed to the pressing member 153 emits light towards the end of the injection plunger 142 located on the pressing member 153 side, and the light-receiving part of the optical sensor 155 detects the amount of light reflected from the injection plunger 142.

[0059] By analyzing the output from sensor 155, contact and / or separation between the injection plunger 142 and the pressing member 153 can be detected using binary or multi-value data. Contact and / or separation detection using binary data can be performed by comparing the output from sensor 155 with a predetermined threshold. Furthermore, by using multi-value data to detect contact and / or separation, information such as the distance between the injection plunger 142 and the pressing member 153, and the pressure applied between them, can be obtained. Moreover, various types of information can be obtained by analyzing the output from sensor 155. For example, synchronized with the output from sensor 155, control device 200 can measure the time from the separation state of injection plunger 142 and pressing member 153 to the contact state of injection plunger 142 and pressing member 153, and / or the time from the contact state of injection plunger 142 and pressing member 153 to the separation state of injection plunger 142 and pressing member 153. Furthermore, based on the measured time, the control device 200 can estimate information about the sliding resistance between the injection cylinder 141 and the injection plunger 142. To estimate the sliding resistance, calculations can be performed using algorithms, LUT processing, or machine learning models. These processes can be performed by the control device 200. In this way, the manufacturing equipment 100 obtains information about the change in sliding resistance between the injection cylinder 141 and the injection plunger 142 based on the time-varying output from the sensor 155. If the sliding resistance changes, the change in back pressure during the metering process or the absolute pressure value during the holding pressure process (a decrease in actual internal pressure) may cause a change in the resin density of the molded product. The resin density of the molded product affects the quality of the molded product. Therefore, changes in the quality of the molded product are detected by detecting changes in sliding resistance using the sensor 155. In this way, the quality of the molded product can be ensured. Specifically, the control device 200 warns (notifies) the operator that the quality of the molded product has changed before mass production of defective products. Therefore, the number of defective products can be reduced. Therefore, molding defects in molded products can be reduced by using the sensor 155.

[0060] Next, a method for manufacturing molded products using manufacturing equipment 100 with the above-described structure will be described in detail. Figures 2 to 5This is a diagram illustrating a manufacturing method for manufacturing molded products using the manufacturing equipment 100 of the first embodiment. Figures 2 to 5 A cross-section of the manufacturing apparatus 100 is schematically shown. In the first embodiment, position and speed control are performed without pressure control in order to control the movement of the pressing member 153. The manufacturing apparatus 100 of the first embodiment sequentially manufactures molded products by repeating metering, injection, and cooling processes. The manufacturing apparatus 100 of the first embodiment can be used to mold products using elastomeric resins that do not require pressure holding. In order to meter the molten resin in the manufacturing apparatus 100, which is a pre-plasticized plunger injection molding machine, the molten resin, which has been plasticized by rotating the plasticizing screw 122, is conveyed to the injection cylinder 141 and stored in the interior 146 of the injection cylinder 141.

[0061] Figure 2 The state of the manufacturing equipment 100 is shown before the metering process begins. When the injection process is complete, i.e., just before the metering process begins, the control device 200 stops the rotation of the plasticizing screw 122. Just before the metering process begins, the injection plunger 142 stops at a buffer position P1. The buffer position P1 is the position where the injection plunger 142 has retracted a predetermined distance (e.g., 2 mm) in the Z2 direction from the buffer position P0. The buffer position P0 is the position where the injection plunger 142 abuts against the contact surface 150 in the interior 146 of the injection cylinder 141.

[0062] The ball 11 of the check valve 131 moves toward the plasticizing screw 122; and as Figure 2 As shown by the dashed circle, with ball 11 positioned on valve seat 51, flow path PT1 is closed. Furthermore, injection plunger 142 and pressing member 153 are in contact with each other.

[0063] Figure 3 The state of the manufacturing equipment 100 performing a metering process is shown. The metering process is the measurement of the amount of molten resin supplied from the plasticizing screw 122 to the injection cylinder 141. During the metering process, the control device 200 retracts the pressing member 153 to the metering completion position P2 by closing the switching valve 143 and by operating the motor 151 to retract the linear motion member 154 in the Z2 direction. That is, during the metering process, the control device 200 controls the motor 151 to move the pressing member 153 to the metering completion position P2. The metering completion position P2 is an example of a first position. For example, the metering completion position P2 is a position 25 mm away from the buffer position P0 in the Z2 direction. The injection plunger 142 remains in the buffer position P1 and is separated from the pressing member 153.

[0064] Then, the control device 200 supplies the molten resin plasticized by the plasticizing screw 122 to the injection cylinder 141 via the flow path PT1 by rotating the plasticizing screw 122 at a predetermined rotational speed (e.g., 50 rpm). When the control device 200 supplies the molten resin to the injection cylinder 141, the ball 11 of the check valve 131 moves toward the injection cylinder 141 and contacts the valve claw 52, ​​as... Figure 3 As shown by the dashed circle. In this contact state, a gap is formed between the ball 11 and the valve claw 52, ​​thereby opening the flow path PT1. The injection plunger 142 is pressed by the pressure of the molten resin that has flowed into the interior 146 of the injection cylinder 141 via the supply inlet S and retracts in the Z2 direction.

[0065] When the injection plunger 142 is separated from the pressing member 153, and molten resin is supplied to the injection cylinder 141 through the plasticizing screw 122, the injection plunger 142 is pressed in the Z2 direction by the molten resin and retracts in the Z2 direction until the injection plunger 142 contacts the pressing member 153.

[0066] Figure 4 The state of the manufacturing equipment 100 when the metering process is completed is shown. The control device 200 determines that the metering of molten resin is complete by determining that the movement of the injection plunger 142 is blocked by the pressing member 153 located at the metering completion position P2. When in contact with the pressing member 153, the injection plunger 142 is prevented from moving in the Z2 direction. If the injection plunger 142 retracts in the Z2 direction and contacts the pressing member 153, the detection value from the sensor 155 provided on the pressing member 153 exceeds a threshold. Upon detecting that the detection value has exceeded the threshold, the control device 200 detects that the injection plunger 142 has contacted the pressing member 153. If the control device 200 detects that the injection plunger 142 has contacted the pressing member 153, the control device 200 stops the rotation of the plasticizing screw 122. Through this operation, the metering process is completed. That is, the control device 200 determines that the metering of molten resin is complete by determining that the injection plunger 142 has contacted the pressing member 153 located at the metering completion position P2.

[0067] During metering, if the injection plunger is forced back by the drive mechanism, air may be drawn into the molten resin contained in the injection cylinder. There are several reasons why air may be drawn into the molten resin. For example, air can be drawn into the injection cylinder from the gap between the injection plunger and the injection cylinder, or from the plasticizing screw. Additionally, when the pressure of the molten resin changes, air dissolved in the molten resin may appear as bubbles. Regardless of the reason, if a molded product is manufactured with air drawn into the molten resin, molding defects such as voids or silver streaks will occur.

[0068] However, in the first embodiment, since the injection plunger 142 is retracted by the pressure of the resin contained in the injection cylinder 141 during the metering process, the amount of air drawn into the molten resin can be reduced compared to the amount of air drawn into the molten resin when the injection plunger 142 is forcibly retracted.

[0069] Figure 5 The state of the manufacturing equipment 100 performing the injection process is shown. During the injection process, the control device 200 opens the switching valve 143 and moves the pressing member 153 forward in the Z1 direction at a predetermined speed (e.g., 20 mm / s). When the injection plunger 142 is pressed towards the Z1 direction by the pressing member 153 moving forward in the Z1 direction, the injection plunger 142 advances in the Z1 direction such that the molten resin contained in the interior 146 of the injection cylinder 141 is injected into the cavity CV via the nozzle N. In this way, while the injection plunger 142 is in contact with the pressing member 153, the injection plunger 142 is pressed and moved forward by the pressing member 153, thereby injecting the molten resin contained in the injection cylinder 141 into the cavity CV of the mold 10. Afterwards, when the injection plunger 142 reaches the buffer position P1, the control device 200 stops the movement of the pressing member 153.

[0070] During injection molding, the resin pressure inside injection cylinder 141 (146) and in flow path PT1 increases. Therefore, the ball 11 of check valve 131 moves toward plasticizing screw 122, and flow path PT1 closes. Because flow path PT1 is closed, the amount of resin flowing back to plasticizing screw 122 is reduced.

[0071] During the injection process, a strong injection reaction force is applied to the pressing member 153. This force causes the housing to which the transmission mechanism 152 is fixed to to bend, resulting in the pressing member 153 tilting slightly relative to the axis C1.

[0072] However, in the first embodiment, even if the pressing member 153 moves forward at a slight angle during the injection process, the outer peripheral surface of the pressing member 153 never contacts the inner peripheral surface 147 of the injection cylinder 141. That is, a gap is formed between the pressing member 153 and the injection cylinder 141, so that the pressing member 153 and the injection cylinder 141 do not contact each other.

[0073] Furthermore, since the front end 1531 of the pressing member 153 is spherical, if the pressing member 153 moves forward at a slight angle, the front end 1531 will also slide on the rear end 1422. Therefore, the load applied to the mating portion between the injection plunger 142 and the injection cylinder 141 can be reduced. As a result, the possibility of the injection plunger 142 getting stuck on the inner circumferential surface 147 of the injection cylinder 141 (i.e., getting stuck) can be reduced.

[0074] After the cavity CV of the mold 10 is filled with molten resin in the injection process, the resin contained in the mold 10 is cooled and cured in a cooling process for a predetermined cooling time (e.g., 7 seconds). Afterward, the mold 10 is opened and the molded product is removed from the mold 10.

[0075] By performing the above processes, molding defects such as voids or silver streaks in molded products can be reduced, and the yield of molded products can be improved.

[0076] Note that in the first embodiment, the above-described metering process for manufacturing the next molded product can be performed during the cooling time of the mold 10.

[0077] Second Embodiment

[0078] Next, a second embodiment will be described. In the second embodiment, the description of features that are the same as in the first embodiment will be simplified or omitted. Figures 6 to 9 This is a diagram illustrating a manufacturing method for manufacturing molded products using manufacturing equipment 100A according to the second embodiment. Figures 6 to 9 A cross-section of manufacturing equipment 100A is schematically shown. (Except in...) Figure 1 In addition to the construction of the manufacturing apparatus 100 shown in the figure and described in the first embodiment, the manufacturing apparatus 100A of the second embodiment also includes a pressure sensor 161.

[0079] In the manufacturing apparatus 100A of the second embodiment, pressure control is performed to control the movement of the pressing member 153. A pressure sensor 161, which is a sensor for detecting the pressure of the resin contained in the injection cylinder 141, is provided in the injection cylinder 141. The pressure value corresponding to the pressure detected by the pressure sensor 161 is sent to the control device 200 and processed by the control device 200. The control device 200 controls the motor 151 by issuing a control command to the motor 151 so that the pressure in the injection cylinder 141 becomes a predetermined pressure.

[0080] The manufacturing equipment 100A of the second embodiment manufactures molded products sequentially through repeated metering, loosening, injection, holding, and cooling processes.

[0081] Figure 6 The diagram shows the state of manufacturing equipment 100A just before the metering process begins. Note that the diameter of the plasticizing screw 122 is, for example, 32 mm. The outer diameter of the pressing member 153 is, for example, 18 mm. The injection plunger 142 is, for example, a cylindrical member with a diameter of 20 mm and a height of 25 mm, and the inner diameter of the injection cylinder 141 is 20.01 mm. Therefore, the difference between the inner diameter of the injection cylinder 141 and the diameter of the injection plunger 142 is 0.01 mm, which is within the range of 2 μm or greater and 50 μm or less.

[0082] When the injection process is completed, that is, just before the metering process is about to begin, the control device 200 stops the rotation of the plasticizing screw 122. Just before the metering process is about to begin, the injection plunger 142 stops at the buffer position P1. The buffer position P1 is the position where the injection plunger 142 is retracted a predetermined distance (e.g., 3 mm) in the Z2 direction from the buffer position P0. The buffer position P0 is the position where the injection plunger 142 abuts against the contact surface 150 in the interior 146 of the injection cylinder 141.

[0083] The ball 11 of the check valve 131 moves toward the plasticizing screw 122, and with the ball 11 in the position on the valve seat 51, the flow path PT1 is closed. Furthermore, the injection plunger 142 and the pressing member 153 are in contact with each other.

[0084] Figure 7 The state of manufacturing equipment 100A performing metering processing is shown. During metering, control device 200 supplies molten resin, plasticized by plasticizing screw 122, to injection cylinder 141 via flow path PT1 by closing switching valve 143 and rotating plasticizing screw 122 at a predetermined speed (e.g., 100 rpm). When control device 200 supplies molten resin to injection cylinder 141, ball 11 of check valve 131 moves toward injection cylinder 141 and contacts valve claw 52. In this contact state, a gap is formed between ball 11 and valve claw 52, ​​thereby opening flow path PT1. Molten resin flows through check valve 131 and supply inlet S and into injection cylinder 141. Through this operation, the pressure of the resin contained in injection cylinder 141 increases.

[0085] In the metering process, a pressure called back pressure is applied to the injection plunger 142 by using the pressing member 153, thereby applying back pressure to the molten resin flowing into the injection cylinder 141 due to the rotation of the plasticizing screw 122. That is, the control device 200 moves the pressing member 153 in the Z2 direction to keep the pressure in the injection cylinder 141 constant (e.g., back pressure of 1 MPa). Specifically, with the rear end 1422 and the front end 1531 in contact with each other and the pressure of the molten resin remaining constant, the control device 200 rotates the plasticizing screw 122 to retract the pressing member 153 in the Z2 direction.

[0086] When the pressing member 153 reaches the metering completion position P2, the control device 200 ends the metering process. Therefore, during the metering process, the control device 200 controls the motor 151 to move the pressing member 153 to the metering completion position P2. The metering completion position P2 is an example of a first position. For example, the metering completion position P2 is a position 60 mm away from the buffer position P0 in the Z2 direction. Afterwards, the control device 200 performs a release process.

[0087] Figure 8The state of manufacturing equipment 100A undergoing a loosening process is shown. This loosening process is performed to reduce molding defects such as resin leakage or drooling from nozzle N, and spraying that may occur in the next injection process. Specifically, in the loosening process, the pressure of the resin contained in injection cylinder 141 is reduced after the metering process is completed.

[0088] During the release process, the control device 200 controls the motor 151 to cause the pressing member 153 to retract along the Z2 direction from the metering completion position P2 to the release completion position P3. The release completion position P3 is an example of a second position. For example, the release completion position P3 is a position that is 65 mm away from the buffer position P0 in the Z2 direction.

[0089] As the pressing member 153 retracts, the injection plunger 142 and the pressing member 153 separate from each other, and the pressing member 153 retracts to the retraction completion position P3 before the injection plunger 142 retracts to the retraction completion position P3. After the pressing member 153 retracts to the retraction completion position P3, the injection plunger 142 is pressed by the molten resin contained in the injection cylinder 141, then retracts to the retraction completion position P3, and then contacts the pressing member 153 again. In this way, the retraction process is performed to reduce drooling and jetting.

[0090] In the second embodiment, during the retraction process, the injection plunger 142 is not forcibly retracted by a drive mechanism or the like, but rather retracted by the resin pressure of the molten resin. Therefore, the injection plunger 142 retracts against the pressure of the resin contained in the injection cylinder 141 during the retraction process. As a result, no gap is generated between the molten resin and the front end 1421 of the injection plunger 142, thereby reducing the amount of air drawn into the molten resin.

[0091] Figure 9 The state of manufacturing equipment 100A performing injection processing is shown. During injection processing, control device 200 opens switching valve 143 and moves pressing member 153 forward in the Z1 direction at a predetermined speed (e.g., 30 mm / s). In this way, while injection plunger 142 is in contact with pressing member 153, injection plunger 142 is pressed and moved forward by pressing member 153, so that molten resin contained in injection cylinder 141 is injected into cavity CV of mold 10. Then, when injection plunger 142 reaches buffer position P1, control device 200 stops the movement of pressing member 153.

[0092] During injection molding, the resin pressure inside injection cylinder 141 (146) and in flow path PT1 increases. Therefore, the ball 11 of check valve 131 moves toward plasticizing screw 122, and flow path PT1 closes. Because flow path PT1 is closed, the amount of resin flowing back to plasticizing screw 122 is reduced.

[0093] After the cavity CV of mold 10 is filled with resin during the injection molding process, the control device 200 performs a pressure holding process. During the pressure holding process, the control device 200 controls the motor 151 to cause the pressing member 153 to press the injection plunger 142, so that the pressure in the injection cylinder 141 is kept constant (e.g., 50 MPa) to compensate for the shrinkage of the molded product in the cavity CV (shrinkage caused by cooling the molded product). After the pressure holding process is completed, the molded product in mold 10 is cooled for a predetermined cooling time (e.g., 10 seconds) during the cooling process. Afterward, mold 10 is opened and the molded product is removed from mold 10.

[0094] By performing the above processes, defects such as voids or silver streaks in molded products can be reduced, and the yield of molded products can be improved.

[0095] In the second embodiment, during the cooling time of the mold 10, the above-described metering and loosening processes for manufacturing the next molded product can be performed.

[0096] Third Embodiment

[0097] Next, a third embodiment will be described. In the third embodiment, a manufacturing apparatus will be described as a family of molding equipment. This family of molding equipment is an example of injection molding equipment and includes a mold capable of molding multiple molded products with different shapes. The mold is configured to define multiple cavities.

[0098] Figures 10 to 12 This is a diagram illustrating a manufacturing method for manufacturing molded products using manufacturing equipment 100B according to the third embodiment. Figures 10 to 12 A cross-section of the manufacturing equipment 100B is shown schematically. Figure 10 The state of manufacturing equipment 100B performing the following injection process is shown. Figure 11 The following pressure holding process is shown in the manufacturing equipment 100B. Figure 12 The status of manufacturing equipment 100B performing the following measurement process is shown.

[0099] Manufacturing equipment 100B includes an injection molding machine 101B, a mold 112B, and a control device 200B. Cavities CV1 and CV2 are defined in the mold 112B. Cavity CV1 is a first cavity, and cavity CV2 is a second cavity. Cavities CV1 and CV2 have different shapes or dimensions. During the holding pressure process, different holding pressures are applied to cavities CV1 and CV2.

[0100] Control device 200B is an example of a control unit. For example, control device 200B is one or more computers, each including a processor. Control device 200B can control the entire manufacturing equipment.

[0101] For example, injection molding machine 101B is an in-line screw injection molding machine. The operation of injection molding machine 101B is controlled by control device 200B. Injection molding machine 101B includes a plasticizing section 111B and an injection section 123B. Molten resin supplied by injection molding machine 101B to mold 112B fills each cavity CV1 and CV2.

[0102] The plasticizing section 111B includes a hopper (not shown), a plasticizing cylinder 121B, and a plasticizing screw 122B. For example, granular resin material is fed into the hopper (not shown). The resin material is, for example, made of a thermoplastic resin, such as polyphenylene ether (PPE). The temperature of the plasticizing cylinder 121B is adjusted to the temperature at which the supplied resin material is plasticized by heating the cylinder 121B with a heater (not shown). The plasticizing screw 122B is disposed within the interior 126B of the plasticizing cylinder 121B. The plasticizing screw 122B is a screw capable of rotation and forward and backward movement. For example, the diameter of the plasticizing screw 122B is 36 mm.

[0103] The injection unit 123B includes a motor (not shown) that moves the plasticizing screw 122B forward and backward while rotating it. The forward movement of the plasticizing screw 122B via the injection unit 123B injects molten resin into the mold 112B. The injection unit 123B is controlled by a control device 200B.

[0104] Manufacturing equipment 100B includes an injection cylinder 141B, an injection plunger 142B, a hot runner 143B, and an injection drive unit 144B. The operation of the injection drive unit 144B is controlled by a control device 200B. The injection cylinder 141B includes a supply inlet S1 for supplying molten resin and a gate G1 for injecting molten resin into a mold cavity CV1. The gate G1 is an example of an injection outlet. The interior 146B of the injection cylinder 141B and the mold cavity CV1 are in communication with each other via the gate G1. Preferably, both the injection cylinder 141B and the injection plunger 142B are made of metal.

[0105] Hot runner 143B is an injection cylinder. A supply inlet for molten resin, located within hot runner 143B, is connected to plasticizing cylinder 121B. Hot runner 143B includes a gate G2 for injecting molten resin into cavity CV2. Gate G2 is an example of an injection outlet. The interior of hot runner 143B and cavity CV2 are in communication with each other via gate G2.

[0106] Furthermore, the manufacturing equipment 100B includes a valve pin V1 for opening and closing gate G1 and a valve pin V2 for opening and closing gate G2. Valve pin V1 is a valve used to prevent molten resin from flowing from gate G1 to the outside of injection cylinder 141B. Valve pin V2 is a valve used to prevent molten resin from flowing from gate G2 to the outside of hot runner 143B. The operation of valve pins V1 and V2 is controlled by control device 200B.

[0107] The hot runner 143B and the injection cylinder 141B are connected to each other via a check valve 131B. The check valve 131B has the same structure as the check valve 131 described in the first and second embodiments. The check valve 131B is connected to the supply inlet S1 and is oriented such that molten resin does not flow back from the injection cylinder 141B to the hot runner 143B. Because the check valve 131B is connected to the supply inlet S1, the molten resin flows in the forward direction from the hot runner 143B towards the injection cylinder 141B, but not in the reverse direction from the injection cylinder 141B towards the hot runner 143B. The resin, melted and plasticized by the plasticizing screw 122B, is supplied to the interior 146B of the injection cylinder 141B via the hot runner 143B, the check valve 131B, and the supply inlet S1 of the injection cylinder 141B. In this way, the molten resin supplied from the plasticizing screw 122B can be stored in the interior 146B of the injection cylinder 141B.

[0108] The injection cylinder 141 includes an inner peripheral surface 147B that defines an internal space. The injection plunger 142B is configured to engage within the injection cylinder 141B such that the injection plunger 142B can move relative to the injection cylinder 141B in the Z direction (i.e., the direction of axis C3).

[0109] The injection drive unit 144B includes a motor 151B, a transmission mechanism 152B, and a pressing member 153B. The motor 151B is an example of a drive source. Preferably, the pressing member 153B is made of metal. The motor 151B may be a rotary motor and is controlled by a control device 200B. The transmission mechanism 152B is a mechanism that transmits the driving force of the motor 151B to the pressing member 153B. For example, the transmission mechanism 152B includes a linear motion mechanism. The transmission mechanism 152B may also include a timing belt. The linear motion mechanism is a mechanism that converts rotary motion into linear motion and may include a ball screw and a nut.

[0110] The linear motion mechanism includes a linear motion member 154B that moves linearly along the Z-direction. A pressing member 153B is connected to the linear motion member 154B. Therefore, in the third embodiment, the motor 151B can drive the pressing member 153B along the Z-direction via a transmission mechanism 152B, causing the pressing member 153B to move linearly along the Z-direction. The pressing member 153B is a component distinct from and separate from the injection plunger 142B. Therefore, the pressing member 153B can contact or separate from the injection plunger 142B.

[0111] Note that the Z1 direction in the Z-direction is defined as the direction in which each of the injection plunger 142B and the pressing member 153B approaches the gate G1 along the axis C3. That is, the Z1 direction is defined as the direction in which molten resin stored in the injection cylinder 141B is injected from the gate G1 into the cavity CV1. Furthermore, the Z2 direction in the Z-direction is defined as the direction in which each of the injection plunger 142B and the pressing member 153B moves away from the gate G1 along the axis C3. The Z2 direction is the opposite of the Z1 direction. Moreover, the movement of each of the injection plunger 142B and the pressing member 153B in the Z1 direction is defined as forward movement, and the movement of each of the injection plunger 142B and the pressing member 153B in the Z2 direction is defined as backward movement. The Z1 direction is an example of a first direction, and the Z2 direction is an example of a second direction. Each of the injection plunger 142B and the pressing member 153B can move along both the Z1 and Z2 directions.

[0112] The pressing member 153B is driven by the motor 151B and moves in the Z direction, allowing it to contact or separate from the injection plunger 142B. Specifically, the pressing member 153B is driven by the motor 151B and moves in the Z1 direction, pressing the injection plunger 142B in the Z1 direction, causing the injection plunger 142B in contact with the pressing member 153B to move in the Z1 direction. Furthermore, the pressing member 153B is driven by the motor 151B and moves in the Z2 direction, allowing it to separate from the injection plunger 142B. In other words, the Z1 direction is the direction in which the pressing member 153B presses the injection plunger 142B, and the Z2 direction is the direction in which the pressing member 153B can separate from the injection plunger 142B.

[0113] The interior 146B of the injection cylinder 141B is a roughly cylindrical space in which the injection plunger 142B can slide along the Z direction.

[0114] The pressing member 153B is a shaft-shaped member extending in the Z direction. The Z direction is equal to the longitudinal direction of the pressing member 153B. The interior 146B of the injection cylinder 141B has a rear end opening in the Z1 direction. The pressing member 153B is inserted into the injection cylinder 141B through the opening, such that the front end of the pressing member 153B in the Z1 direction is located in the interior 146B of the injection cylinder 141B. The front end of the pressing member 153B in the Z1 direction is the first part facing the injection plunger 142B. The rear end of the pressing member 153B in the Z1 direction is connected to the linear motion member 154B.

[0115] The injection plunger 142B is a generally cylindrical component. For example, the diameter of the injection plunger 142B is 8 mm. The injection plunger 142B includes a rear end and a front end. The rear end is formed at the rear end of the injection plunger 142B along the Z1 direction and contacts the front end of the pressing member 153B. The front end is formed at the front end of the injection plunger 142B along the Z1 direction and contacts the molten resin injected into the injection cylinder 141B. The rear end of the injection plunger 142B is an example of a second portion facing the pressing member 153B. The rear end of the injection plunger 142B is the portion in the Z direction opposite to the front end of the injection plunger 142B. At least the front end of the injection plunger 142B is located within the interior 146B of the injection cylinder 141B. In a third embodiment, the entire injection plunger 142B is located within the interior 146B of the injection cylinder 141B.

[0116] Preferably, at least one of the front end of the pressing member 153B and the rear end of the injection plunger 142B is spherical. Therefore, the pressing member 153B and the injection plunger 142B are in point contact with each other. In a third embodiment, the front end of the pressing member 153B is spherical, and the rear end of the injection plunger 142B is flat. Note that the rear end of the injection plunger 142B can be spherical, while the front end of the pressing member 153B can be flat. In another case, both the rear end of the injection plunger 142B and the front end of the pressing member 153B can be spherical.

[0117] The injection plunger 142B mates with (or contacts) the inner circumferential surface 147B, allowing it to slide in the Z-direction within the interior 146B of the injection cylinder 141B. The inner diameter of the injection cylinder 141B is larger than the diameter of the portion of the injection plunger 142B that mates within the injection cylinder 141B. Preferably, the difference between the inner diameter of the injection cylinder 141B and the diameter of the portion of the injection plunger 142B that mates within the injection cylinder 141B is equal to or greater than 2 μm and equal to or less than 50 μm. Because this difference is equal to or greater than 2 μm and equal to or less than 50 μm, resin leakage from the gap between the injection cylinder 141B and the injection plunger 142B can be effectively reduced. Furthermore, the possibility of the injection plunger 142B being stuck by the inner circumferential surface 147B of the injection cylinder 141B (i.e., jamming) can be effectively reduced.

[0118] The diameter of the pressing member 153B is made smaller than the diameter of the injection plunger 142B, so that the pressing member 153B does not contact the inner circumferential surface 147B of the injection cylinder 141B. Therefore, the pressing member 153B does not contact the injection cylinder 141B. That is, the pressing member 153B is separated from the injection cylinder 141B.

[0119] Next, a method for manufacturing molded products using manufacturing equipment 100B having the above-described structure will be described. Figure 10 The state of the manufacturing equipment 100B performing injection molding is shown. During injection molding, the control device 200B opens the gate G1 leading to cavity CV1 while the gate G2 leading to cavity CV2 is closed, and moves the plasticizing screw 122B of the injection molding machine 101B forward at a predetermined speed (e.g., 50 mm / s). Molten resin injected from the injection molding machine 101B flows through a flow path formed in the hot runner 143B and passes through the check valve 131B. The molten resin that has passed through the check valve 131B passes through gate G1 and fills cavity CV1. The control device 200B opens gate G2 when the volume of the portion of cavity CV1 that does not contain molten resin becomes equal to a predetermined volume (e.g., 30 cc). Through this operation, molten resin also flows into cavity CV2, allowing cavities CV1 and CV2, which have different volumes, to be filled with molten resin simultaneously. When cavities CV1 and CV2 have been filled with molten resin, the front end of the pressing member 153B remains in the metering completion position P2, and the injection plunger 142B and the pressing member 153B are in contact with each other. The metering completion position P2 is an example of a first position. For example, the metering completion position P2 is a position that is 20 mm away from the buffer position P0 in the Z2 direction.

[0120] Figure 11The state of manufacturing equipment 100B performing a pressure holding process is shown. During the pressure holding process, control device 200B applies a first holding pressure to cavity CV1 by controlling injection drive unit 144B, and applies a second holding pressure lower than the first holding pressure to cavity CV2 by controlling injection molding machine 101B. During the pressure holding process, control device 200B applies a predetermined holding pressure (e.g., 80 MPa) to the flow path of injection cylinder 141B for a predetermined time (e.g., 3 seconds) by pressing injection plunger 142B with pressing member 153B. On the other hand, control device 200B applies a predetermined pressure (e.g., 50 MPa) to the flow path of hot runner 143B of injection molding machine 101B for a predetermined time (e.g., 3 seconds) via plasticizing screw 122B. During the pressure holding process, the pressure of the resin on the outflow side from check valve 131B is greater than the pressure of the resin on the inflow side into check valve 131B. Therefore, check valve 131B is closed. As a result, a holding pressure of 80 MPa applied by the injection plunger 142B is applied to cavity CV1, and a holding pressure of 50 MPa applied by the plasticizing screw 122B of the injection molding machine 101B is applied to cavity CV2. After the holding pressure process is completed, gates G1 and G2 are closed. When the holding pressure process is complete, the injection plunger 142B is located in buffer position P1. For example, buffer position P1 is a position that is 2 mm away from buffer position P0 in the Z2 direction.

[0121] Figure 12The state of manufacturing equipment 100B performing metering processing is shown. During metering, control device 200B retracts pressing member 153B to metering completion position P2 by operating motor 151B. When pressing member 153B retracts to metering completion position P2, injection plunger 142 remains in or near buffer position P1 and separates from pressing member 153B. Then, control device 200B applies a back pressure of 2 MPa by rotating plasticizing screw 122B of injection molding machine 101B at a predetermined speed (e.g., 100 rpm). As a result, the pressure of resin on the outflow side from check valve 131B becomes less than the pressure of resin on the inflow side into check valve 131B. Therefore, check valve 131B opens, and molten resin, melted and plasticized by plasticizing screw 122B of injection molding machine 101B, flows through hot runner 143B and into the interior of injection cylinder 141B. Furthermore, the injection plunger 142B is pressed in the Z2 direction and retracted by the pressure of the molten resin flowing into the injection cylinder 141B, until the injection plunger 142B contacts the pressing member 153B, which is stopped at the metering completion position P2. Meanwhile, the plasticizing screw 122B of the injection molding machine 101B continues to move backward while rotating until the metering of the amount of resin required for the next injection is completed. After the metering performed by the injection molding machine 101B is completed and the cooling time has passed, the molded product is removed from the cavities CV1 and CV2. Then, the control device 200B performs another injection process.

[0122] In the third embodiment, since the injection plunger 142B retracts during the metering process due to the pressure of the resin contained in the injection cylinder 141B, the amount of air drawn into the molten resin can be reduced compared to the amount of air drawn into the molten resin when the injection plunger 142B is forcibly retracted.

[0123] By performing the above processes, defects such as voids or silver streaks in molded products can be reduced, and the yield of molded products can be improved.

[0124] Variant

[0125] In the first to third embodiments described above, various modifications can be made to the injection cylinder, injection plunger, and pressing component.

[0126] First variant

[0127] Figure 13AThis is a schematic cross-sectional view of the injection cylinder 141C, injection plunger 142C, and pressing member 153C of the first variant. Preferably, each of the injection cylinder 141C, injection plunger 142C, and pressing member 153C is made of metal. For example, the injection cylinder 141C is made of high-speed steel. For example, the injection plunger 142C is made of powdered high-speed steel. For example, the pressing member 153C is made of high-speed steel. As in the first to third embodiments, the direction of forward and backward movement of the injection plunger 142C is defined as the Z direction, the direction of forward movement of the injection plunger 142C is defined as the Z1 direction, and the direction of backward movement of the injection plunger 142C is defined as the Z2 direction. The Z1 direction is the direction of molten resin injection, and the Z2 direction is the opposite direction to the Z1 direction.

[0128] The injection plunger 142C includes a front end portion 1421C formed along the Z1 direction and a rear end portion 1422C formed along the Z1 direction. The front end portion 1421C of the injection plunger 142C is located inside the injection cylinder 141C 146C, and the rear end portion 1422C of the injection plunger 142C is located outside the injection cylinder 141C.

[0129] The interior 146C of the injection cylinder 141C is a cylindrical space defined by the inner peripheral surface 147C of the injection cylinder 141C. The injection plunger 142C includes a cylindrical shaft portion 41C that inserts into the interior 146C and a flange portion 42C that abuts against the abutment surface 150C of the injection cylinder 141C. Therefore, the shaft portion 41C of the injection plunger 142C mates with the inner peripheral surface 147C of the injection cylinder 141C.

[0130] In the first variant, the front end of the shaft portion 41C is the front end 1421C of the injection plunger 142C, and the rear end of the flange portion 42C is the rear end 1422C of the injection plunger 142C. Therefore, the front end 1421C is included in the shaft portion 41C, and the rear end 1422C is included in the flange portion 42C.

[0131] The pressing member 153C includes a front end portion 1531C formed along the Z1 direction. The front end portion 1531C of the pressing member 153C can be made to contact or separate from the rear end portion 1422C of the injection plunger 142C (i.e., the rear end portion of the flange 42C). Since the flange 42C is located outside the injection cylinder 141C, the pressing member 153C, which can contact or separate from the flange 42C, remains in a non-contact state where the pressing member 153C does not contact the injection cylinder 141C. That is, the pressing member 153C remains in a state where the pressing member 153C is separated from the injection cylinder 141C.

[0132] Preferably, at least one of the rear end portion 1422C of the injection plunger 142C facing the pressing member 153C and the front end portion 1531C of the pressing member 153C facing the injection plunger 142C is formed as a sphere. The front end portion 1531C is an example of a first part, and the rear end portion 1422C is an example of a second part.

[0133] exist Figure 13A In the example, the front end 1531C is formed as a sphere, and the rear end 1422C is formed as a flat surface. Therefore, the injection plunger 142C and the pressing member 153C are in point contact with each other. Note that the rear end 1422C can be spherical, and the front end 1531C can be flat. In another case, both the rear end 1422C and the front end 1531C can be spherical.

[0134] The inner diameter of the injection cylinder 141C is larger than the diameter of the shaft portion 41C of the injection cylinder 141C. Preferably, the difference between the inner diameter of the injection cylinder 141C and the diameter of the shaft portion 41C of the injection plunger 142C is equal to or greater than 2 μm and equal to or less than 50 μm. Because this difference is equal to or greater than 2 μm and equal to or less than 50 μm, resin leakage from the gap between the injection cylinder 141C and the shaft portion 41C of the injection plunger 142C can be effectively reduced. In addition, the possibility of the injection plunger 142C being stuck by the inner circumferential surface 147C of the injection cylinder 141C (i.e., jamming) can be effectively reduced.

[0135] In the first variant, since the rear end 1422C of the injection plunger 142C is exposed to the outside, pulling the injection plunger 142C out of the injection cylinder 141C facilitates maintenance, such as cleaning. Therefore, maintainability is improved.

[0136] Furthermore, since the rear end portion 1422C is included in the flange portion 42C, the injection plunger 142C can be easily pulled out of the injection cylinder 141C by hooking a tool onto the flange portion 42C. This further improves maintainability.

[0137] Second variant

[0138] Figure 13B This is a schematic cross-sectional view of the second variant's injection cylinder 141D, injection plunger 142D, and pressing member 153D. Preferably, each of the injection cylinder 141D, injection plunger 142D, and pressing member 153D is made of metal. As in the first to third embodiments, the direction of forward and backward movement of the injection plunger 142D is defined as the Z direction, the direction of forward movement of the injection plunger 142D is defined as the Z1 direction, and the direction of backward movement of the injection plunger 142D is defined as the Z2 direction. The Z1 direction is the direction of molten resin injection, and the Z2 direction is the opposite direction to the Z1 direction.

[0139] The injection plunger 142D includes a front end portion 1421D formed along the Z1 direction and a rear end portion 1422D formed along the Z1 direction. The front end portion 1421D of the injection plunger 142D is located inside the injection cylinder 141D 146D, and the rear end portion 1422D of the injection plunger 142D is located outside the injection cylinder 141D.

[0140] The interior 146D of the injection cylinder 141D is a cylindrical space defined by the inner circumferential surface 147D of the injection cylinder 141D. The injection plunger 142D includes a cylindrical shaft portion 41D inserted into the interior 146D, a cylindrical shaft portion 40D inserted into the interior 146D with a diameter larger than that of the shaft portion 41D, and a flange portion 42D capable of abutting against the abutting surface 150D of the injection cylinder 141D. The shaft portion 40D is located on the Z1 direction side relative to the shaft portion 41D. Therefore, the shaft portion 40D of the injection plunger 142D mates with the inner circumferential surface 147D of the injection cylinder 141D.

[0141] In the second variation, the front end of the shaft portion 40D is the front end 1421D of the injection plunger 142D, and the rear end of the flange portion 42D is the rear end 1422D of the injection plunger 142D. Therefore, the front end 1421D is included in the shaft portion 40D, and the rear end 1422D is included in the flange portion 42D.

[0142] The pressing member 153D includes a front end portion 1531D formed along the Z1 direction. The front end portion 1531D of the pressing member 153D can be made to contact or separate from the rear end portion 1422D of the injection plunger 142D (i.e., the rear end portion of the flange 42D). Since the flange 42D is located outside the injection cylinder 141D, the pressing member 153D, which can contact or separate from the flange 42D, remains in a non-contact state where the pressing member 153D does not contact the injection cylinder 141D. That is, the pressing member 153D remains in a state where the pressing member 153D is separated from the injection cylinder 141D.

[0143] Preferably, at least one of the rear end portion 1422D of the injection plunger 142D facing the pressing member 153D and the front end portion 1531D of the pressing member 153D facing the injection plunger 142D is formed as a sphere. The front end portion 1531D is an example of a first part, and the rear end portion 1422D is an example of a second part.

[0144] exist Figure 13B In the example, the front end 1531D is formed as a sphere, and the rear end 1422D is formed as a flat surface. Therefore, the injection plunger 142D and the pressing member 153D are in point contact with each other. Note that the rear end 1422D can be spherical, and the front end 1531D can be flat. In another case, both the rear end 1422D and the front end 1531D can be spherical.

[0145] The inner diameter of the injection cylinder 141D is larger than the diameter of the shaft portion 40D of the injection plunger 142D. Preferably, the difference between the inner diameter of the injection cylinder 141D and the diameter of the shaft portion 40D of the injection plunger 142D is equal to or greater than 2 μm and equal to or less than 50 μm. Because this difference is equal to or greater than 2 μm and equal to or less than 50 μm, resin leakage from the gap between the injection cylinder 141D and the shaft portion 40D of the injection plunger 142D can be effectively reduced. Furthermore, the possibility of the injection plunger 142D being stuck by the inner circumferential surface 147D of the injection cylinder 141D (i.e., jamming) can be effectively reduced.

[0146] In the second variant, since the rear end 1422D of the injection plunger 142D is exposed to the outside, pulling the injection plunger 142D out of the injection cylinder 141D facilitates maintenance, such as cleaning. Therefore, maintainability is improved.

[0147] Furthermore, since the rear end portion 1422D is included in the flange portion 42D, the injection plunger 142D can be easily pulled out of the injection cylinder 141D by hooking a tool onto the flange portion 42D. This further improves maintainability.

[0148] The contact area between the injection plunger 142D and the inner circumferential surface 147D in the second variant is smaller than the contact area between the injection plunger 142C and the inner circumferential surface 147C in the first variant. Therefore, compared with the situation in the first variant where the injection plunger 142C is stuck by the inner circumferential surface 147C of the injection cylinder 141C, the situation where the injection plunger 142D is stuck by the inner circumferential surface 147D of the injection cylinder 141D can be reduced more effectively.

[0149] Fourth embodiment

[0150] Figure 13C This is a schematic cross-sectional view of the injection cylinder 141E, injection plunger 142E, and pressing member 153E of the manufacturing apparatus according to the fourth embodiment. Preferably, each of the injection cylinder 141E, injection plunger 142E, and pressing member 153E is made of metal. As in the first to third embodiments, the forward and backward movement directions of the injection plunger 142E are defined as the Z direction, the forward movement direction of the injection plunger 142E is defined as the Z1 direction, and the backward movement direction of the injection plunger 142E is defined as the Z2 direction. The Z1 direction is the direction of molten resin injection, and the Z2 direction is the opposite direction to the Z1 direction.

[0151] The injection plunger 142E includes a front end portion 1421E formed along the Z1 direction and a rear end portion 1422E formed along the Z1 direction. The front end portion 1421E of the injection plunger 142E is located inside the injection cylinder 141E 146E, and the rear end portion 1422E of the injection plunger 142E is located outside the injection cylinder 141E.

[0152] The injection cylinder 141E includes a base 61E and a sleeve 62E. The sleeve 62E is detachably mounted to the base 61E. The injection plunger 142E fits into the sleeve 62E.

[0153] The sleeve 62E includes an inner circumferential surface 148E defining a cylindrical opening. The opening of the sleeve 62E communicates with the interior of the base 61E. The interior of the base 61E is also cylindrical. The diameter of the opening of the sleeve 62E is smaller than the diameter of the interior of the base 61E. The opening of the sleeve 62E and the interior of the base 61E are included in the interior 146E of the injection cylinder 141E. The interior 146E of the injection cylinder 141E is a space defined by the inner circumferential surface 147E of the injection cylinder 141E.

[0154] The injection plunger 142E includes a cylindrical shaft portion 41E inserted into the interior 146E and a flange portion 42E that abuts against the abutment surface 150E of the injection cylinder 141E. The abutment surface 150E is included in the sleeve 62E. In the fourth embodiment, the shaft portion 41E of the injection plunger 142E is inserted into the opening of the sleeve 62E and mates with the inner circumferential surface 148E of the sleeve 62E. For example, the mating length of the mating portion between the injection plunger 142E and the sleeve 62E in the Z direction is 35 mm.

[0155] In the fourth embodiment, the front end of the shaft portion 41E is the front end 1421E of the injection plunger 142E, and the rear end of the flange portion 42E is the rear end 1422E of the injection plunger 142E. Therefore, the front end 1421E is included in the shaft portion 41E, and the rear end 1422E is included in the flange portion 42E.

[0156] The pressing member 153E includes a front end portion 1531E formed along the Z1 direction. The front end portion 1531E of the pressing member 153E can be made to contact or separate from the rear end portion 1422E of the injection plunger 142E (i.e., the rear end portion of the flange 42E). Since the flange 42E is located outside the injection cylinder 141E, the pressing member 153E, which can contact or separate from the flange 42E, remains in a non-contact state where the pressing member 153E does not contact the injection cylinder 141E. That is, the pressing member 153E remains in a state where the pressing member 153E is separated from the injection cylinder 141E.

[0157] Preferably, at least one of the rear end portion 1422E of the injection plunger 142E facing the pressing member 153E and the front end portion 1531E of the pressing member 153E facing the injection plunger 142E is formed as a sphere. The front end portion 1531E is an example of a first part, and the rear end portion 1422E is an example of a second part.

[0158] exist Figure 13CIn the example, the front end 1531E is formed as a sphere, and the rear end 1422E is formed as a flat surface. Therefore, the injection plunger 142E and the pressing member 153E are in point contact with each other. Note that the rear end 1422E can be spherical, and the front end 1531E can be flat. In another case, both the rear end 1422E and the front end 1531E can be spherical.

[0159] The inner diameter of the sleeve 62E of the injection cylinder 141E is larger than the diameter of the shaft portion 41E of the injection plunger 142E. Preferably, the difference between the inner diameter of the sleeve 62E of the injection cylinder 141E and the diameter of the shaft portion 41E of the injection plunger 142E is equal to or greater than 2 μm and equal to or less than 50 μm. Because this difference is equal to or greater than 2 μm and equal to or less than 50 μm, resin leakage from the gap between the sleeve 62E of the injection cylinder 141E and the shaft portion 41E of the injection plunger 142E can be effectively reduced. In addition, the possibility of the injection plunger 142E being stuck by the inner circumferential surface 148E of the sleeve 62E of the injection cylinder 141E (i.e., being jammed) can be effectively reduced.

[0160] In the fourth embodiment, since the rear end 1422E of the injection plunger 142E is exposed to the outside, pulling the injection plunger 142E out of the injection cylinder 141E facilitates maintenance, such as cleaning. Therefore, maintainability is improved.

[0161] Furthermore, since the rear end portion 1422E is included in the flange portion 42E, the injection plunger 142E can be easily pulled out of the injection cylinder 141E by hooking a tool onto the flange portion 42E. This further improves maintainability.

[0162] The injection plunger 142E does not contact the base 61E of the injection cylinder 141E. Therefore, the contact area between the injection plunger 142E and the inner circumferential surface 147E is smaller than the contact area between the injection plunger 142C and the inner circumferential surface 147C in the first variant. That is, the injection plunger 142E only contacts the inner circumferential surface 148E of the sleeve 62E in the inner circumferential surface 147E. Therefore, in the fourth embodiment, compared with the case in the first variant where the injection plunger 142C is stuck by the inner circumferential surface 147C of the injection cylinder 141E, the situation where the injection plunger 142E is stuck by the inner circumferential surface 147E of the injection cylinder 141E can be reduced more effectively.

[0163] Furthermore, since the sleeve 62E is detachably mounted to the base 61E, if the mating part between the injection cylinder 141E and the injection plunger 142E wears out during long-term use, the sleeve 62E only needs to be replaced with another sleeve 62E. This further improves maintainability.

[0164] The injection plunger 142E includes a portion that slides on the injection cylinder 141E. Resin that has adhered to the portion of the injection plunger 142E that slides on the injection cylinder 141E may leak to the outside of the injection cylinder 141E and may remain on the outside of the injection cylinder 141E.

[0165] Figure 14 This is a diagram showing a portion of the manufacturing apparatus according to the fourth embodiment. Figure 14 A cross-section of a portion of the manufacturing apparatus according to the fourth embodiment is shown. Figure 14 In this configuration, the gap between the sleeve 62E and the base 61E is sealed by a sealing member 63 (e.g., an O-ring). Figure 14 In this configuration, the sleeve 62E is fixed (tightened) to the base 61E of the injection cylinder 141E by screws 64. Therefore, the sleeve 62E is pressed against the base 61E of the injection cylinder 141E by the screws 64. When the injection plunger 142E moves, the injection plunger 142E and the sleeve 62E slide on each other. Preferably, the area of ​​the portion of the injection plunger 142E that slides on the sleeve 62E is larger than the area of ​​the portion of the sleeve 62E that slides on the injection plunger 142E.

[0166] The shaft portion 41E of the injection plunger 142E includes a part that fits into and slides on the injection cylinder 141E. The diameter of the shaft portion 41E of the injection plunger 142E is denoted by L1. The inner diameter of the sleeve 62E is denoted by L2. The inner diameter of the base 61E is denoted by L3. For example, the mating length of the mating portion between the injection plunger 142E and the sleeve 62E in the Z direction is denoted by L4.

[0167] The amount of resin leakage M can be represented by the following expression (1).

[0168]

[0169] Expression (1) is an expression for the flow rate of fluid flowing through the gap between the two surfaces of a concentric cylinder (in expression (1) it is assumed that the gap is formed between the two surfaces).

[0170] In expression (1), parameter b represents the diameter or gap width. Furthermore, parameter l represents the gap length, parameter h represents the gap height, parameter η represents the fluid viscosity, and parameters P1-P2 represent the pressure difference. From expression (1), it can be understood that as parameter l increases or parameter b decreases, the resin leakage M can be reduced.

[0171] Note that parameter l corresponds to the mating length L4, and parameter b corresponds to the diameter L1 of the shaft portion 41E. That is, in order to reduce the amount of resin leakage M, the mating length L4 should be larger, and / or the diameter L1 of the shaft portion 41E should be smaller.

[0172] Therefore, it is preferable that the mating length L4 is greater than the diameter L1. As an experimental result, it is preferable that the mating length L4 is equal to or greater than 103% of the diameter L1 of the shaft portion 41E. However, if the mating length L4 is too large, the sliding performance deteriorates. Therefore, it is preferable that the mating length L4 is equal to or less than 270% of the diameter L1 of the shaft portion 41E. For example, it is preferable that the value of the diameter L1 is in the range of 5 to 12.5 mm and the value of the mating length L4 is in the range of 12.5 to 20 mm.

[0173] The diameter L1 of the shaft portion 41E is smaller than the inner diameter L2 of the sleeve 62E. Preferably, the difference between the diameter L1 of the shaft portion 41E and the inner diameter L2 of the sleeve 62E is in the range of 0.001 to 0.010 mm.

[0174] The inner diameter L2 of the sleeve 62E can be equal to the inner diameter L3 of the base 61E of the injection cylinder 141E. However, it is preferable that the inner diameter L2 of the sleeve 62E is smaller than the inner diameter L3 of the base 61E. As an experimental result, it is preferred that the inner diameter L2 of the sleeve 62E is equal to or greater than 99.0% of the inner diameter L3 of the base 61E and less than 100.0% of the inner diameter L3 of the base 61E. More preferably, the inner diameter L2 of the sleeve 62E is equal to or greater than 99.5% of the inner diameter L3 of the base 61E and equal to or less than 99.8% of the inner diameter L3 of the base 61E. For example, it is preferred that the inner diameter L2 of the sleeve 62E is smaller than the inner diameter L3 of the base 61E by a value in the range of 0.01 to 0.1 mm.

[0175] If the gap between the base 61E and the injection plunger 142E of the injection cylinder 141E is too large, this gap may cause resin remaining in the gap to leak to the outside of the injection cylinder 141E. Therefore, in the fourth embodiment, the inner diameter L3 of the base 61E is made as close as possible to the inner diameter L2 of the sleeve 62E. In this way, the gap between the base 61E and the injection plunger 142E is made as small as possible, thereby reducing resin leakage.

[0176] Figure 15A and Figure 15B This is a diagram showing a portion of the manufacturing apparatus according to the fourth embodiment. Figure 15A and Figure 15B A cross-section of a portion of the manufacturing apparatus according to the fourth embodiment is shown. Figure 15A and Figure 15B In this embodiment, a chamfer 42 is formed on the front end of the injection plunger 142E. The chamfer 42 may be a C-shaped chamfer. The chamfer is formed such that the edge of the un-chamfered front end of the injection plunger 142E is chamfered by a distance of approximately 0.1 to 1.0 mm, preferably in the range of 0.2 to 0.6 mm. The width of the chamfer 42 is in the range of approximately 0.15 to 1.5 mm.

[0177] exist Figure 15BIn this process, a chamfered portion 43 is also formed on the side of the base 61E inside the sleeve 62E. Because the chamfered portion 43 is formed, a step L5 is formed on the surface formed by the inner wall of the sleeve 62E and the inner wall of the base 61E (i.e., on the surface facing the side surface of the shaft portion 41E). The depth of the step L5 corresponds to the depth of the chamfered portion 43.

[0178] If a step is formed between the sleeve 62E and the substrate 61E, resin will easily accumulate in the step, and the viscosity of the resin accumulated in the step will easily increase. The high-viscosity resin accumulated in the step may adhere to the injection plunger and may cause resin leakage. Therefore, it is preferable to make the step between the sleeve 62E and the substrate 61E as small as possible. The step formed between the sleeve 62E and the substrate 61E can have a size of approximately (L3-L2) / 2. Preferably, the step formed between the sleeve 62E and the substrate 61E is smaller than the difference between the inner diameter L3 of the substrate 61E and the diameter L1 of the injection plunger 142E (i.e., L3-L1). More preferably, the size of the step formed between the sleeve 62E and the substrate 61E is equal to or less than the value of (L3-L1) / 2. For example, if a chamfer is formed on the sleeve 62E and / or the base 61E (e.g., if a chamfer 43 is formed on the sleeve 62E), the dimension of the step L5 formed between the sleeve 62E and the base 61E may be larger than the value of L3-L1. For example, the value of L3-L1 is in the range of 0.01 to 0.1 mm. The step L5 formed by the chamfer 43 (similar to the chamfer 42 of the injection plunger 142E) may have a dimension in the range of 0.1 to 1.0 mm. If a chamfer with a depth of approximately 0.1 to 1.0 mm is formed on the sleeve 62E or the base 61E, the step L5 formed between the sleeve 62E and the base 61E has a dimension of approximately 0.1 to 1.0 mm. Therefore, the dimension of the step L5 will exceed the value of L3-L1, which is in the range of approximately 0.01 to 0.1 mm. Therefore, it is preferable that a chamfer with a size of approximately 0.1 to 1.0 mm is not formed on the portion of the sleeve 62E on the base 61E side or on the portion of the base 61E on the sleeve 62E side. Preferably, as Figure 15A The step between the sleeve 62E and the base 61E shown is as small as possible. Figure 15B The step between the sleeve 62E and the base 61E is shown. For example, it is preferable that the step L5 is less than the value of L3-L1 (L5 < L3-L1). More preferably, the step L5 is equal to or less than half the value of L3-L1, that is, L5 ≤ (L3-L1) / 2.

[0179] Preferably, a crystalline layer comprising crystals with a grain size of 10 nm to 1 μm is formed on the surface of the injection plunger 142E. The grain size is preferably in the range of 50 to 500 nm, more preferably in the range of 100 to 300 nm. Typically, the grain size of polycrystalline metal materials ranges from a few micrometers to tens of micrometers. However, since a crystalline layer (nanocrystalline layer, microcrystalline layer) comprising nanocrystals (microcrystals) with a grain size equal to or less than 1 μm is formed on (and near) the surface of the injection plunger 142E, wear resistance, fatigue strength, and sliding properties are enhanced. This surface treatment can be performed using shot peening. Shot peening is a cold working method in which numerous spherical particles (called abrasives or media) collide with the workpiece at high speed. During shot peening, the spherical particles colliding with the workpiece can cause uneven plastic deformation, suppress the growth of cracks caused by compressive residual stress, and achieve surface modification by increasing wear resistance through increased surface hardness. Note that the crystalline layer described above can be applied to injection plungers in other embodiments.

[0180] Fifth embodiment

[0181] Next, a fifth embodiment will be described. In the fifth embodiment, the description of features that are the same as in the first embodiment will be simplified or omitted. Figure 16 This is a schematic cross-sectional view of the manufacturing equipment 100F according to the fifth embodiment.

[0182] In the manufacturing apparatus 100 of the first embodiment described above, the injection plunger 142 and the injection drive unit 144 are separate. That is, the injection plunger 142 can be brought into contact with or separated from the pressing member 153. In the manufacturing apparatus 100F of the fifth embodiment, the pressing member 153 and the injection plunger 142 of the manufacturing apparatus 100 of the first embodiment are replaced by the injection plunger 142F. That is, the injection plunger 142F is connected to the linear motion member 154 of the injection drive unit 144. The other structures of the manufacturing apparatus 100F are the same as those of the manufacturing apparatus 100 of the first embodiment. The injection plunger 142F can be driven in the Z direction by the motor 151. The control device 200 is capable of controlling the motor 151. That is, the control device 200 can control (drive) the motor 151 so that the injection plunger 142F moves in the Z direction.

[0183] When the control device 200 supplies molten resin to the injection cylinder 141, the control device 200 stops the motor 151, allowing the injection plunger 142F to move in the Z2 direction. If position and speed control is performed as in the first embodiment, the motor 151 is stopped during the metering process. Since the motor 151 does not generate driving force after stopping, the injection plunger 142F can move in the Z2 direction by the pressure of the molten resin. When the control device 200 injects molten resin from the injection cylinder 141, the control device 200 drives the motor 151, allowing the injection plunger 142F to move in the Z1 direction.

[0184] In another example, when the supply of molten resin to injection cylinder 141 is complete, control device 200 can stop motor 151, thereby allowing injection plunger 142F to move in the Z2 direction. If pressure control is performed as in the second embodiment, motor 151 stops during the release process. Since motor 151 does not generate driving force after stopping, injection plunger 142F can be moved in the Z2 direction by the pressing pressure of the molten resin.

[0185] As described above, in the fifth embodiment, molding defects such as voids or silver streaks in the molded products can also be reduced, and the yield of the molded products can be increased.

[0186] Note that the construction and control operations in the fifth embodiment described above can be applied to the third embodiment described above.

[0187] As described above, this disclosure can provide techniques that help reduce molding defects in molded products.

[0188] This disclosure is not limited to the embodiments described above, and modifications to the embodiments can be made in various ways within the scope of the technical concept of this disclosure. Furthermore, the effects described in the embodiments are merely examples of the most preferred effects obtainable from the embodiments of this disclosure, and the effects of the embodiments of this disclosure are not limited to those described in the embodiments.

[0189] Furthermore, the disclosure in this specification includes not only what is described herein, but also all matters that can be understood from this specification and its accompanying drawings. Moreover, the disclosure in this specification includes the complement of the concepts described herein. Therefore, if this specification contains a description indicating, for example, "A is B," then even if the description indicating "A is not B" is omitted, this specification can still be said to disclose a description indicating "A is not B." This is because the presence of a description indicating "A is B" presupposes the possibility that "A is not B."

[0190] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims should be given the broadest interpretation to cover all variations and equivalent structures and functions.

Claims

1. A manufacturing apparatus, comprising: An injection cylinder to which molten resin is supplied and configured to inject molten resin; An injection plunger is configured such that the injection plunger engages in an injection cylinder and moves in a first direction and a second direction opposite to the first direction; and The pressing member is configured to be able to separate from the injection plunger and to press the injection plunger to move the injection plunger toward a first direction; The injection cylinder includes a matrix configured to contain molten resin and a sleeve configured to be detachably mounted onto the matrix. The injection plunger is configured to be inserted into the interior of the substrate via an opening formed in the sleeve and slide on the sleeve. In this process, with the pressing component separated from the injection plunger, the injection plunger is moved in the second direction by pressing it with molten resin supplied to the injection cylinder. The injection plunger is separate from the matrix.

2. The manufacturing equipment according to claim 1, further comprising: The sensor is configured to detect contact and / or separation between the injection plunger and the pressing member.

3. The manufacturing equipment according to claim 1, further comprising: A drive source configured to drive the pressing member along a first direction and a second direction; and The control unit is configured to control the drive source. The control unit is configured as follows: The control drive source moves the pressing member to a first position as molten resin is metered and supplied to the injection cylinder, and The drive source is controlled to inject molten resin after the pressing member has been retracted to a second position from the first position.

4. The manufacturing equipment according to any one of claims 1 to 3, wherein, At least the front end of the injection plunger is located inside the injection cylinder.

5. The manufacturing equipment according to any one of claims 1 to 3, wherein, The entire injection plunger is located inside the injection cylinder.

6. The manufacturing equipment according to any one of claims 1 to 3, wherein, The rear end of the injection plunger is located outside the injection cylinder.

7. The manufacturing equipment according to claim 1, wherein, The area of ​​the portion of the injection plunger that slides on the sleeve is greater than the area of ​​the portion of the sleeve that slides on the injection plunger.

8. The manufacturing equipment according to claim 1, wherein, The mating length between the sleeve and the injection plunger is greater than the diameter of the injection plunger.

9. The manufacturing equipment according to claim 1, wherein, The mating length of the fitting portion between the sleeve and the injection plunger is equal to or greater than 103% of the injection plunger diameter and equal to or less than 270% of the injection plunger diameter.

10. The manufacturing equipment according to claim 1, wherein, The inner diameter of the sleeve is smaller than the inner diameter of the base material.

11. The manufacturing equipment according to claim 1, wherein, The manufacturing equipment is configured to meet at least one of the following conditions: The inner diameter of the sleeve is equal to or greater than 99.0% of the inner diameter of the base material and less than 100.0% of the inner diameter of the base material, or The difference between the inner diameter of the sleeve and the inner diameter of the base is in the range of 0.01 to 0.1 mm.

12. The manufacturing equipment according to claim 1, wherein, The step between the sleeve and the base is smaller than the difference between the diameter of the injection plunger and the inner diameter of the base.

13. The manufacturing equipment according to any one of claims 1 to 3, wherein, The pressing component is configured to be separate from the injection cylinder.

14. The manufacturing equipment according to any one of claims 1 to 3, wherein, At least one of the first portion of the pressing member facing the injection plunger or the second portion of the injection plunger facing the pressing member is formed in a spherical shape.

15. The manufacturing equipment according to any one of claims 1 to 3, wherein, The difference between the inner diameter of the injection cylinder and the diameter of the portion of the injection plunger that fits within the injection cylinder is equal to or greater than 2 μm and equal to or less than 50 μm.

16. The manufacturing equipment according to any one of claims 1 to 3, wherein, The injection cylinder includes a supply inlet for supplying molten resin, and The manufacturing equipment also includes valves configured to prevent molten resin from flowing from the supply inlet to the outside of the injection cylinder.

17. The manufacturing equipment according to any one of claims 1 to 3, wherein, The injection cylinder includes an injection outlet from which molten resin is discharged, and The manufacturing equipment also includes a valve configured to prevent molten resin from flowing from the injection outlet to the outside of the injection cylinder.

18. The manufacturing equipment according to any one of claims 1 to 3, further comprising: The mold is configured to define a specific cavity. In this process, molten resin is injected into the mold cavity.

19. The manufacturing equipment according to any one of claims 1 to 3, further comprising: The mold is configured to define multiple cavities. Molten resin is injected into the plurality of cavities.

20. The manufacturing equipment according to claim 1 or 2, further comprising: A drive source configured to drive the pressing member along a first direction and a second direction; and The control unit is configured as a control drive source.

21. The manufacturing equipment according to claim 20, wherein, The control unit is configured to control the drive source to move the pressing member to a first position when the pressing member is separated from the injection plunger when molten resin is metered and supplied to the injection cylinder.

22. The manufacturing equipment according to claim 21, wherein, The control unit is configured to determine that the metering of molten resin is completed by determining that the movement of the injection plunger is blocked by the pressing member located in the first position.

23. The manufacturing equipment according to claim 1 or 3, further comprising: Sensors are used to detect contact between the injection plunger and the pressing member or separation between the injection plunger and the pressing member.

24. The manufacturing equipment according to claim 2, wherein, The sensor is an optical sensor.

25. The manufacturing equipment according to claim 2, wherein, The manufacturing equipment is configured to obtain information about the changes in sliding resistance between the injection cylinder and the injection plunger based on the time-varying output from sensors.

26. The manufacturing equipment according to claim 21, wherein, The control unit is configured to control the drive source to retract the pressing member to a second position retracting from the first position toward the second direction; In this process, with the pressing member in the second position, the injection plunger is moved in the second direction by pressing the injection plunger with molten resin supplied to the injection cylinder.

27. The manufacturing equipment according to claim 1, further comprising: The driving source is configured to drive the injection plunger; and The control unit is configured to control the drive source. The control unit is configured to drive the drive source to move the injection plunger toward a first direction when molten resin is injected from the injection cylinder. The control unit is configured to stop the drive source when molten resin is supplied to the injection cylinder or when the supply of molten resin to the injection cylinder is completed, so as to allow the injection plunger to move in the second direction.

28. A method for manufacturing a molded product, comprising manufacturing the molded product using the manufacturing equipment according to any one of claims 1 to 27, the method comprising: The molten resin in the injection cylinder is injected into the cavity of the mold.

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