Injection molding machine and control method for an injection molding machine

Abstract

This disclosure relates to an injection molding machine and a control method for the injection molding machine. At least one of a metering operation and an injection operation is performed based on pressure detection values ​​to improve the accuracy of the molded article. The injection molding machine includes: a melting section having a spiral member rotating around a rotation axis and having a groove forming surface, and a barrel having a communicating hole on an opposing surface opposite to the groove forming surface; the melting section plasticizes material to generate a plasticized material, and the plasticized material flows out from the communicating hole; a heating section for heating the melting section; an injection nozzle communicating with the communicating hole and injecting the plasticized material into a molding die; an injection control section having a cylinder and a plunger connected to the communicating hole; a pressure detection section for detecting the pressure of the plasticized material flowing into the communicating hole; and a control section. The control section controls the injection control section and performs at least one of a metering operation and an injection operation based on the detection values.

Description

[0001] This application is a divisional application of patent application filed on December 23, 2020, with application number 202011539745.7 and entitled "Injection Molding Machine and Control Method for Injection Molding Machine", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to an injection molding machine and a method for controlling the injection molding machine. Background Technology

[0003] Patent Document 1 discloses an injection molding machine that plasticizes resin using a plasticizing delivery device and meters and injects the plasticized resin into a mold using a metering injection device with a plunger. The plasticizing delivery device of the injection molding machine includes: a rotor having a spiral groove; and a barrel having a central through hole and abutting against the end face of the rotor.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2010-241016

[0005] In the aforementioned plasticizing apparatus, since resin is plasticized while being conveyed from the outer periphery of the rotor to the center at the rotor's end face, the plasticizing state and the amount of plasticized resin may fluctuate if the balance between conveying and plasticizing is disrupted due to factors such as temperature changes. For example, if the plunger operates at a constant speed during metering, air may enter the metering injection device, leading to excessive resin supply and affecting molding quality. Furthermore, if the plunger operates at a constant speed during injection, uneven pressure of the resin injected into the mold may result in insufficient resin filling the mold, increased internal stress in the molded object, and other issues affecting molding quality. Summary of the Invention

[0006] According to a first aspect of this disclosure, an injection molding machine is provided. The injection molding machine comprises: a melting section having a auger and a barrel, the auger rotating about a rotation axis and having a groove forming surface, the barrel having a counter surface opposite to the groove forming surface and having a connecting hole on the counter surface, the melting section plasticizing material supplied between the auger and the barrel to generate a plasticized material, and the plasticized material flowing out from the connecting hole; a heating section for heating the melting section; an injection nozzle communicating with the connecting hole; an injection control section having a cylinder connected to the connecting hole and a plunger moving within the cylinder; a pressure detection section for detecting the pressure of the plasticized material within the connecting hole; and a control section. The control unit controls the injection control unit, and the control unit performs at least one of a metering operation and an injection operation based on the detection value detected by the pressure detection unit. In the metering operation, the plastic material in the communicating hole is metered in the cylinder by moving the plunger away from the communicating hole. In the injection operation, the plastic material in the cylinder is injected into the molding die via the injection nozzle by moving the plunger towards the communicating hole.

[0007] According to a second aspect of this disclosure, an injection molding machine is provided. The injection molding machine comprises: a melting section having a auger and a barrel, the auger rotating about a rotation axis and having a groove-forming surface, the barrel having a counter-surface opposite to the groove-forming surface and having a connecting hole on the counter-surface, the melting section plasticizing material supplied between the auger and the barrel to generate a plasticized material, and the plasticized material flowing out from the connecting hole; a supply flow path communicating with the connecting hole; a heating section for heating the melting section; an injection nozzle communicating with the supply flow path; an injection control section having a cylinder connected to the supply flow path and a plunger moving within the cylinder; a pressure detection section for detecting the pressure of the plasticized material within the supply flow path; and a control section. The control unit controls the injection control unit, and the control unit performs at least one of a metering operation and an injection operation based on the detection value detected by the pressure detection unit. In the metering operation, the plasticizing material in the supply flow path is metered in the cylinder by moving the plunger away from the supply flow path. In the injection operation, the plasticizing material in the cylinder is injected into the molding die via the injection nozzle by moving the plunger towards the supply flow path.

[0008] According to a third aspect of this disclosure, a control method for an injection molding machine is provided. In this control method, the injection molding machine comprises: a melting section having a auger and a barrel; the auger rotating about a rotation axis and having a groove-forming surface; the barrel having a counter-surface opposite to the groove-forming surface and a communicating hole on the counter-surface; the melting section plasticizing material supplied between the auger and the barrel to generate a plasticized material, and causing the plasticized material to flow out from the communicating hole; a heating section for heating the melting section; an injection nozzle communicating with the communicating hole; and an injection control section having a cylinder connected to the communicating hole and a plunger moving within the cylinder. The pressure of the plasticizing material within the connecting hole is detected, and based on the detected pressure value, the injection control unit is controlled to perform at least one of a metering operation and an injection operation. In the metering operation, the plasticizing material within the connecting hole is metered in the cylinder by moving the plunger away from the connecting hole. In the injection operation, the plasticizing material in the cylinder is injected via the injection nozzle by moving the plunger towards the connecting hole. Attached Figure Description

[0009] Figure 1 This is a first explanatory diagram showing the schematic structure of the injection molding machine in the first embodiment.

[0010] Figure 2 This is a second explanatory diagram showing the schematic structure of the injection molding machine in the first embodiment.

[0011] Figure 3 It is a three-dimensional diagram showing the structure of the groove-forming surface of the spiral component.

[0012] Figure 4 This is an explanatory diagram showing the structure of the opposite side of the barrel.

[0013] Figure 5 This is an explanatory diagram showing the general structure of the pressure detection unit.

[0014] Figure 6 This is a flowchart illustrating the injection molding process in the first embodiment.

[0015] Figure 7 This is an explanatory diagram illustrating the metering operation in the first embodiment.

[0016] Figure 8 This is a chart illustrating an example of pressure changes in plasticizers during metering operations.

[0017] Figure 9 This is a flowchart illustrating the injection molding process in the second embodiment.

[0018] Figure 10 This is an explanatory diagram illustrating the injection operation in the second embodiment.

[0019] Figure 11 This is a chart illustrating an example of pressure changes in the plasticizer during an injection process.

[0020] Figure 12 This is an explanatory diagram showing the schematic structure of the injection molding machine in the third embodiment.

[0021] Figure 13 This is a flowchart illustrating the injection molding process in the fourth embodiment.

[0022] Figure 14 This is an explanatory diagram showing the schematic structure of the injection molding machine in the fifth embodiment.

[0023] Figure 15 This is an explanatory diagram showing the schematic structure of the pressure detection unit in the fifth embodiment.

[0024] Figure 16 This is an explanatory diagram illustrating the metering operation in the fifth embodiment.

[0025] Figure 17 This is an explanatory diagram illustrating the injection operation in the fifth embodiment.

[0026] Figure 18 This is an explanatory diagram showing the schematic structure of the injection molding machine in the sixth embodiment.

[0027] Explanation of reference numerals in the attached figures

[0028] 10, 10c, 10e… Injection molding machine; 100, 100c, 100e… Injection unit; 110… Material supply section; 120, 120c, 120e… Melting section; 121… Spiral housing; 122… Drive motor; 130… Spiral; 132… Groove forming surface; 133… Side surface; 134… Material inlet; 135… Groove section; 136… Raised section; 137… Central section; 138… Retention suppression section; 140, 140e… Barrel; 142… Opposing surface; 143, 143e… Through hole; 144… Guide groove; 146… Connecting hole; 148… Heating section; 149… Check valve; 150, 150e… Injection control section; 151, 151e… Cylinder; 152… 152e…plunger; 153, 153e…plunger drive unit; 155…supply flow path; 156…injection nozzle; 160…mold unit; 161…forming mold; 162…movable mold; 163…fixed mold; 170…mold closing device; 171…mold drive unit; 172…ball screw unit; 190, 190e…support unit; 191…recess; 195, 195e…heat suppression unit; 196, 196e…foot unit; 197, 197e…space; 200, 200e…pressure detection unit; 201, 201e…rod; 202, 202e…flange unit; 203, 203e…front end; 204, 204e…rear end; 210…cooling unit; 500…control unit. Detailed Implementation

[0029] A. First implementation method:

[0030] Figure 1 This is a first explanatory diagram showing the schematic structure of the injection molding machine 10 in this embodiment. Figure 1 The diagram shows arrows along the mutually orthogonal X, Y, and Z directions. The X, Y, and Z directions are directions along three mutually orthogonal spatial axes: the X-axis, Y-axis, and Z-axis, each including both directions along one side of the X, Y, and Z axes and directions opposite to them. The X and Y axes are along the horizontal plane, and the Z-axis is along the vertical line. Arrows along the X, Y, and Z directions are also appropriately shown in other diagrams. Figure 1 The X, Y, and Z directions in this diagram represent the same directions as those in other diagrams.

[0031] The injection molding machine 10 includes an injection unit 100, a material supply unit 110, a mold unit 160, and a mold closing device 170. The injection molding machine 10 uses the injection unit 100 to plasticize the material supplied from the material supply unit 110 to generate plasticized material, and injects the plasticized material into the mold unit 160 to form a molded article.

[0032] Figure 2This is a second explanatory diagram showing the schematic structure of the injection molding machine 10. Figure 2 The image shows an injection unit 100, a mold section 160, and a mold closing device 170 of an injection molding machine 10. The injection unit 100 includes a melting section 120, an injection control section 150, an injection nozzle 156, a pressure detection section 200, and a control section 500.

[0033] Figure 1 The material supply unit 110 shown is Figure 2 The molten section 120 shown is connected. The material supply section 110 supplies material to the molten section 120 of the injection unit 100. In this embodiment, the material supply section 110 is composed of a hopper. The material supply section 110 contains materials in the form of granules, powders, etc. In this embodiment, ABS resin in granular form is stored in the material supply section 110 as material.

[0034] The melting section 120 includes a spiral housing 121, a drive motor 122, a spiral 130, a barrel 140, a heating section 148, and a check valve 149. The melting section 120 plasticizes at least a portion of the material supplied from the material supply section 110, generating a fluid, paste-like plasticized material and guiding it to the injection control section 150. "Plasticization" refers to the softening of a thermoplastic material by heating it to a temperature above its glass transition point, thus exhibiting fluidity. "Melting" refers not only to a thermoplastic material becoming liquid by heating it to a temperature above its melting point, but also to the plasticization of a thermoplastic material. It should be noted that the spiral 130 of this embodiment is sometimes referred to as a "planar spiral" or a "vortex."

[0035] The auger 130 has a generally cylindrical shape with a height less than its diameter along its central axis RX. The auger 130 is housed in a space surrounded by the auger housing 121 and the barrel 140. The auger 130 has a groove-forming surface 132 on the surface opposite to the barrel 140, where a groove 135 is provided. Specifically, the groove-forming surface 132 of the auger 130 faces the opposite surface 142 of the barrel 140. A drive motor 122 is connected to the surface of the auger 130 opposite to the groove-forming surface 132. The auger 130 rotates around its central axis RX due to the torque generated by the drive motor 122. The drive motor 122 is driven under the control of the control unit 500. It should be noted that the central axis RX is sometimes referred to as the rotation axis of the auger 130.

[0036] Figure 3 This is a perspective view showing the structure of the groove forming surface 132 side of the spiral member 130. Figure 3 In the diagram, the position of the central axis RX of the spiral member 130 is indicated by a single-dot dashed line. As described above, a groove 135 is provided on the groove forming surface 132.

[0037] The groove 135 of the auger 130 forms a so-called vortex groove. The groove 135 extends in a vortex-like manner, curving from the central portion 137 toward the outer periphery of the auger 130. The groove 135 may also be configured to extend in an involute or spiral shape. A raised strip 136, constituting the sidewall portion of the groove 135, is provided on the groove forming surface 132 and extends along each groove 135. The groove 135 continues to a material inlet 134 provided on the side surface 133 of the auger 130. This material inlet 134 is the portion of the groove 135 that receives material. Material supplied from the material supply unit 110 is supplied between the auger 130 and the barrel 140 via the material inlet 134.

[0038] The central portion 137 of the groove forming surface 132 of the spiral member 130 is configured as a recess that connects to one end of the groove portion 135. For example... Figure 2 As shown, the central portion 137 is opposite to the communicating hole 146 provided on the opposing surface 142 of the barrel 140. The central portion 137 intersects the central axis RX.

[0039] In this embodiment, the screw 130 has a retention-inhibiting portion 138 protruding toward the connecting hole 146 in its central portion 137. In this embodiment, the retention-inhibiting portion 138 has a generally conical shape, and its central axis is approximately aligned with the central axis RX of the screw 130. The front end of the retention-inhibiting portion 138 is positioned further inside the connecting hole 146 than the opening end of the connecting hole 146 on the opposing surface 142. Because the plasticizing material in the central portion 137 is efficiently guided to the connecting hole 146 via the retention-inhibiting portion 138, retention of the plasticizing material is prevented. Retention of the plasticizing material is sometimes referred to as "stagnation."

[0040] exist Figure 3 An example of a spiral member 130 with three grooves 135 and three ridges 136 is shown. The number of grooves 135 and ridges 136 provided on the spiral member 130 is not limited to three. The spiral member 130 may have only one groove 135 or more grooves 135. In addition, any number of ridges 136 may be provided depending on the number of grooves 135.

[0041] exist Figure 3 An example of a spiral member 130 with material inlets 134 formed at three locations is shown. The number of material inlets 134 provided on the spiral member 130 is not limited to three locations. In the spiral member 130, the material inlets 134 may be provided at only one location, or at multiple locations with two or more locations.

[0042] Figure 4This is an explanatory diagram showing the structure of the opposing surface 142 side of the barrel 140. As described above, the barrel 140 has an opposing surface 142 opposite to the groove forming surface 132 of the auger 130. A communication hole 146 communicating with the injection nozzle 156 is provided in the center of the opposing surface 142. A plurality of guide grooves 144 are provided around the communication hole 146 on the opposing surface 142. One end of each guide groove 144 is connected to the communication hole 146 and extends in a spiral shape from the communication hole 146 toward the outer periphery of the opposing surface 142. Each guide groove 144 has the function of guiding the molding material to the communication hole 146. It should be noted that in order to make the molding material reach the communication hole 146 efficiently, it is preferable to form guide grooves 144 on the barrel 140, but it is also possible not to form guide grooves 144.

[0043] The heating unit 148 heats the melting section 120. In this embodiment, the heating unit 148 consists of four heaters installed inside the barrel 140. The output of the heating unit 148 is controlled by the control unit 500.

[0044] A check valve 149 is provided inside the connecting hole 146. The check valve 149 suppresses the backflow of plasticizing material from the connecting hole 146 to the central portion 137 and the groove portion 135 of the spiral member 130.

[0045] The melting section 120, through the aforementioned spiral member 130, barrel 140, and heating section 148, heats and generates plasticized material while conveying the material supplied between the spiral member 130 and barrel 140 toward the connecting hole 146, and then the plasticized material flows out from the connecting hole 146 to the injection control section 150.

[0046] like Figure 2 As shown, the injection control unit 150 includes a cylinder 151, a plunger 152, and a plunger drive unit 153. The cylinder 151 is a generally cylindrical component connected to the communication hole 146 of the barrel 140. The plunger 152 moves inside the cylinder 151. The plunger 152 is driven by the plunger drive unit 153, which is composed of a motor, gears, etc. The plunger drive unit 153 is controlled by the control unit 500.

[0047] Under the control of the control unit 500, the injection control unit 150 performs metering and injection operations by sliding the plunger 152 within the cylinder 151. The metering operation refers to the operation of introducing plasticized material from the connecting hole 146 into the cylinder 151 by moving the plunger 152 away from the connecting hole 146 in the -X direction, and metering it within the cylinder 151. The injection operation refers to the operation of injecting plasticized material from the cylinder 151 into the molding die via the injection nozzle 156 by moving the plunger 152 towards the connecting hole 146 in the +X direction. It should be noted that moving the plunger 152 away from the connecting hole 146 is sometimes referred to as pulling the plunger 152. Additionally, moving the plunger 152 towards the connecting hole 146 is sometimes referred to as pushing the plunger 152.

[0048] As described above, the injection nozzle 156 is connected to the connecting hole 146. By performing the metering and injection operations described above, the plasticized material metered in the cylinder 151 is transported from the injection control unit 150 to the injection nozzle 156 via the connecting hole 146, and then injected from the injection nozzle 156 into the mold unit 160.

[0049] The mold section 160 has a molding die 161. Plasticized material delivered to the injection nozzle 156 is injected from the injection nozzle 156 into the mold cavity Cv of the molding die 161. Specifically, the molding die 161 has a movable die 162 and a fixed die 163 opposite to each other, with the mold cavity Cv between them. The mold cavity Cv is a space corresponding to the shape of the molded article. In this embodiment, the movable die 162 and the fixed die 163 are formed of a metallic material. It should be noted that the movable die 162 and the fixed die 163 may also be formed of a ceramic material or a resin material.

[0050] The mold closing device 170 includes a mold drive unit 171 and a ball screw unit 172. The mold drive unit 171 consists of a motor, gears, etc., and is connected to the movable mold 162 via the ball screw unit 172. The drive of the mold drive unit 171 is controlled by the control unit 500. The ball screw unit 172 transmits the power generated by the drive of the mold drive unit 171 to the movable mold 162. Under the control of the control unit 500, the mold closing device 170 opens and closes the mold unit 160 by moving the movable mold 162 using the mold drive unit 171 and the ball screw unit 172.

[0051] Figure 5 This is an explanatory diagram showing the schematic structure of the pressure sensing unit 200. The pressure sensing unit 200 detects the pressure of the plasticized material within the connecting hole 146. In this embodiment, the pressure sensing unit 200 is supported by a support portion 190. The support portion 190 and the pressure sensing unit 200 are disposed in a recess 191 provided in the lower part of the barrel 140.

[0052] The support portion 190 is fixed to the barrel 140 by bolts (not shown). The support portion 190 has a heat suppression portion 195. The heat suppression portion 195 suppresses heat conduction from the molten portion 120 to the pressure detection portion 200, and is disposed between the pressure detection portion 200 and the molten portion 120. The heat suppression portion 195 has multiple feet 196. Multiple spaces 197 are formed between the molten portion 120 and the support portion 190 through the multiple feet 196. Heat conduction from the molten portion 120 to the pressure detection portion 200 is suppressed through the air in the spaces 197. In other embodiments, the heat suppression portion 195 may also be made of a heat-insulating material such as glass wool.

[0053] In this embodiment, the pressure detection unit 200 detects the pressure of the plasticized material within the communicating hole 146 via a rod 201. The rod 201 is a shaft-shaped component with a flange 202. The rod 201 is disposed along the X direction within a through hole 143 provided in the barrel 140. The through hole 143 is disposed along the X direction, allowing the communicating hole 146 to communicate with the recess 191 via the through hole 143. The front end portion 203, which is one end of the rod 201, is disposed facing the interior of the communicating hole 146. The rear end portion 204, which is the other end of the rod 201, is disposed opposite the pressure detection unit 200 in the recess 191. The flange 202 is formed midway along the X direction of the rod 201. The flange 202 is disposed in the -X direction of the through hole 143 to restrict the movement of the rod 201 in the +X direction.

[0054] The rod 201 receives pressure from the plasticized material in the connecting hole 146 through its front end 203, and transmits the pressure to the pressure detection unit 200 through its rear end 204. The pressure detection unit 200 detects the pressure transmitted from the rod 201.

[0055] In this embodiment, the pressure detection unit 200 detects the pressure of the plasticizing material downstream of the connecting hole 146, which is closer to the downstream end of the cylinder body 151 and the connecting hole 146. Specifically, the pressure detection unit 200 detects the pressure of the plasticizing material via a rod 201 disposed in the connecting hole 146, which is closer to the downstream end of the connecting hole 146 than the cylinder body 151 and the connecting hole 146.

[0056] The pressure detection unit 200 of this embodiment is composed of a pressure sensor with a crystal. The pressure detection unit 200 utilizes the piezoelectric effect of the crystal to detect the pressure received by the pressure detection unit 200 as an electrical signal. The pressure detection unit 200 is controlled by the control unit 500 via wiring (not shown), and sends the detected pressure value as an electrical signal to the control unit 500. The pressure detection unit 200 can be, for example, composed of a pressure sensor with other piezoelectric elements, or it can be composed of an electrostatic capacitive pressure sensor.

[0057] Figure 6This is a flowchart illustrating the injection molding process in this embodiment. Alternatively, it can be described as... Figure 6 An example of a control method for an injection molding machine 10 is shown. The control unit 500 performs the injection molding process by controlling the injection unit 100 and the mold clamping device 170. It should be noted that in this embodiment, the pressure detection unit 200... Figure 6 Throughout the entire injection molding process shown, the pressure of the plastic material within the connecting hole 146 is continuously monitored, and the monitored values ​​are continuously sent to the control unit 500.

[0058] In step S110, the control unit 500 controls the melting unit 120 to plasticize the material supplied from the material supply unit 110, thereby generating a plasticized material.

[0059] In step S120, the control unit 500 controls the plunger drive unit 153 to start the metering operation. In this embodiment, as shown after step S130, the control unit 500 performs the metering operation based on the detection value detected by the pressure detection unit 200. Specifically, the control unit 500 adjusts the speed at which the plunger 152 is pulled based on the detection value.

[0060] Figure 7 This is an explanatory diagram illustrating the metering operation in this embodiment. During the metering operation, by pulling the plunger 152, the connecting hole 146 is filled with plasticizing material, and the plasticizing material is guided into the cylinder 151. The pressure detection unit 200 detects the pressure of the plasticizing material in the connecting hole 146 during this metering operation. Figure 7 In the diagram, the flow of plastic material during the metering operation is indicated by solid lines and arrows. Additionally, the pressure of the plastic material transmitted via rod 201 to the pressure sensing unit 200 and within the connecting hole 146 is indicated by dashed lines and arrows.

[0061] Figure 8 This is a graph illustrating, for example, the pressure changes of plasticizers during metering operations. Figure 8 In the diagram, the detection value Pr, continuously detected by the pressure detection unit 200 during the metering operation, corresponding to time t, is represented by a solid line. Additionally, the first reference value P1 and the second reference value P2 corresponding to time t are represented by a dashed line. The second reference value P2 is a value greater than the first reference value P1. The first reference value P1 and the second reference value P2 are, for example, predetermined as values ​​representing the amount of plasticizing material used for highly accurate molding of the molded article.

[0062] exist Figure 6In step S130, the control unit 500 determines whether the detection value Pr is greater than or equal to the first reference value P1. If, in step S130, it is determined that the detection value Pr is not greater than or equal to the first reference value P1, in step S140, the control unit 500 pulls the plunger 152 at a speed lower than the first reference speed. That is, during the metering operation, if the detection value Pr is less than the first reference value P1, the control unit 500 pulls the plunger 152 at a speed lower than the first reference speed. The first reference speed is, for example, predetermined as a speed at which the detection value Pr is greater than or equal to the first reference value P1 and less than or equal to the second reference value P2 when plasticizing material is ideally supplied from the molten section 120.

[0063] like Figure 8 As shown, at time t1, the detected value Pr is less than the first reference value P1. At time t1, if the plunger 152 is pulled at the first reference speed, for example, air may mix into the cylinder 151. At time t1, the control unit 500 suppresses air mixing and improves the metering accuracy of the plasticizing material by pulling the plunger 152 at a speed lower than the first reference speed.

[0064] exist Figure 6 In step S130, if it is determined that the detected value Pr is greater than or equal to the first reference value P1, in step S150, the control unit 500 determines whether the detected value Pr is greater than the second reference value P2. If it is determined in step S150 that the detected value Pr is not greater than the second reference value P2, in step S160, the control unit 500 pulls the plunger 152 at a first reference speed. That is, during the metering operation, when the detected value Pr is greater than or equal to the first reference value P1 and less than or equal to the second reference value P2, the control unit 500 pulls the plunger 152 at a first reference speed.

[0065] In step S150, if it is determined that the detected value Pr is greater than the second reference value P2, in step S170, the control unit 500 pulls the plunger 152 at a speed higher than the first reference speed. That is, during the metering operation, if the detected value Pr exceeds the second reference value P2, the control unit 500 pulls the plunger 152 at a speed higher than the first reference speed.

[0066] like Figure 8As shown, at time t2, the detection value Pr exceeds the second reference value P2. At this time, when the plunger 152 is pulled at the first reference speed, compared to the case where the detection value Pr is above the first reference value P1 and below the second reference value P2, more plastic material is introduced into the cylinder 151. The control unit 500 can suppress the supply of excess plastic material into the cylinder 151 by pulling the plunger 152 at a speed higher than the second reference speed at time t2. It should be noted that the change in the detection value Pr at times t1 and t2 is caused, for example, by changes in the amount and state of the plastic material generated in the molten section 120. These changes are caused, for example, by changes in the temperature of the molten section 120.

[0067] In step S180, the control unit 500 determines whether the metering operation is complete. If it is determined in step S180 that the metering operation is not complete, the control unit 500 returns the process to step S130 and continues the injection molding process. It should be noted that the control unit 500 determines that the metering operation is complete, for example, when the metering of the plasticized material required for molding has ended from the position of the plunger 152.

[0068] If the metering operation is determined to be complete in step S180, in step S190, the control unit 500 controls the plunger drive unit 153 to perform the injection operation. The plasticized material metered in the cylinder 151 in step S130 is injected into the mold cavity Cv of the mold unit 160 via the injection nozzle 156 through the injection operation in step S190. It should be noted that the injection operation may also include a pressure holding operation to maintain the pressure of the plasticized material in the mold cavity Cv.

[0069] According to the injection molding machine 10 of this embodiment described above, the control unit 500 controls the injection control unit 150 to perform metering operations based on the detection value Pr detected by the pressure detection unit 200. Therefore, even if the amount or state of the plasticized material generated by the molten section 120 changes, high metering accuracy can be maintained. Consequently, the injection accuracy of the plasticized material is improved, and the molding accuracy of the molded article is improved.

[0070] Furthermore, in this embodiment, during the metering operation, the speed at which the plunger 152 is pulled is adjusted based on the detected value Pr. Therefore, high metering accuracy of the plasticizing material can be maintained, and the injection accuracy of the plasticizing material is improved.

[0071] Furthermore, in this embodiment, during the metering operation, the control unit 500 pulls the plunger 152 at a first reference speed when the detected value Pr is above the first reference value P1 and below the second reference value P2; when the detected value Pr is less than the first reference value P1, it pulls the plunger 152 at a speed lower than the first reference speed; and when the detected value Pr exceeds the second reference value P2, it pulls the plunger 152 at a speed higher than the first reference speed. Therefore, high metering accuracy of the plasticized material can be maintained, and the plasticized material can be metered efficiently.

[0072] Furthermore, in this embodiment, a heat suppression section 195 is provided between the pressure detection section 200 and the molten section 120. Therefore, the deterioration of the pressure detection section 200 caused by heat transfer from the molten section is suppressed, and the freedom of placement of the pressure detection section 200 is increased.

[0073] Furthermore, in this embodiment, the pressure detection unit 200 detects the pressure of the plasticizing material closer downstream of the connecting hole 146 than the connection between the cylinder 151 and the connecting hole 146. Therefore, the injection control unit 150 controls the injection operation by using the detected pressure value of the plasticizing material at a position closer to the injection nozzle 156. Consequently, the amount of injected plasticizing material is more stable, and injection accuracy is improved.

[0074] Furthermore, in this embodiment, the spiral member 130 has a retention-inhibiting portion protruding toward the connecting hole 146 at the central portion 137 of the groove forming surface 132. As a result, retention of the plasticizing material at the central portion 137 is suppressed. Therefore, the amount and state of the plasticizing material delivered from the molten portion 120 to the injection nozzle 156 via the connecting hole 146 are stable, and the injection accuracy of the plasticizing material is improved.

[0075] It should be noted that during the metering operation, the control unit 500 pulls the plunger 152 at a first reference speed when the detected value Pr is above the first reference value P1 and below the second reference value P2; when the detected value Pr is less than the first reference value P1, it pulls the plunger 152 at a speed lower than the first reference speed; and when the detected value Pr exceeds the second reference value P2, it pulls the plunger 152 at a speed higher than the first reference speed. As long as the processing follows this pattern, it can also be performed in conjunction with... Figure 6 The injection molding process shown is different.

[0076] B. Second implementation method:

[0077] Figure 9 This is a flowchart illustrating the injection molding process in the second embodiment. Alternatively, it can be said that... Figure 9An example of the control method for the injection molding machine 10 in the second embodiment is shown. In the injection molding process of the second embodiment, unlike the first embodiment, the metering operation is not performed based on the detection value Pr, but rather the injection operation is performed based on the detection value Pr. The structure of the injection molding machine 10 in the second embodiment is the same as that in the first embodiment, therefore, description is omitted.

[0078] Step S210 and Figure 6 Step S110 of the first embodiment shown is the same, so the description is omitted.

[0079] In step S220, the control unit 500 controls the plunger drive unit 153 to perform a metering operation. In this embodiment, the control unit 500 performs the metering operation not based on the detection value Pr of the pressure detection unit 200.

[0080] In step S230, the control unit 500 controls the plunger drive unit 153 to start the injection operation. In this embodiment, the control unit 500 performs the injection operation based on the detection value detected by the pressure detection unit 200. Specifically, the control unit 500 pushes the plunger 152 based on the detection value.

[0081] Figure 10 This is an explanatory diagram illustrating the injection operation in this embodiment. During the injection operation, by pushing the plunger 152, the plasticized material in the cylinder 151, metered by the metering operation in step S220, is conveyed through the connecting hole 146 to the injection nozzle 156. Then, the plasticized material is injected through the injection nozzle 156 into the mold cavity Cv of the mold section 160. The pressure detection unit 200 detects the pressure of the plasticized material in the connecting hole 146 during this injection operation. Figure 10 In the diagram, the flow of plastic material during the injection operation is represented by solid lines and arrows. Additionally, the pressure of the plastic material transmitted via rod 201 to the communication hole 146 of the pressure detection unit 200 is represented by dashed lines and arrows.

[0082] Figure 11 This is a graph illustrating, for example, the pressure changes of the plasticizer during an injection molding process. Figure 11 In the diagram, the detection value Pr corresponding to time t is represented by a solid line. Additionally, the third reference value P3 and the fourth reference value P4 corresponding to time t are represented by dashed lines. The fourth reference value P4 is a value greater than the third reference value P3. The third reference value P3 and the fourth reference value P4 are, for example, predetermined as values ​​of pressure used for high-precision molding of the molded article.

[0083] exist Figure 9In step S240, the control unit 500 determines whether the detection value Pr is greater than or equal to the third reference value P3. If, in step S240, it is determined that the detection value Pr is not greater than or equal to the third reference value P3, in step S250, the control unit 500 pushes the plunger 152 at a speed higher than the second reference speed. That is, during the injection operation, if the detection value Pr is less than the third reference value P3, the control unit 500 pushes the plunger 152 at a speed higher than the second reference speed. The second reference speed is, for example, predetermined as a speed at which the detection value Pr is greater than or equal to the third reference value P3 and less than or equal to the fourth reference value P4, provided that the plasticizing material is ideally supplied from the melt section 120 and ideally metered in the injection control unit 150.

[0084] like Figure 11 As shown, at time t3, the detection value Pr is less than the third reference value P3. At time t3, when the plunger 152 is pushed at the second reference speed, the amount of plasticized material injected into the mold section 160 via the injection nozzle 156 is less than the case where the detection value Pr is above the third reference value P3 and below the fourth reference value P4. The control unit 500 can suppress insufficient injection of plasticized material into the mold section 160 by pushing the plunger 152 at a speed higher than the second reference speed at time t3. It should be noted that this insufficient injection of plasticized material is sometimes referred to as incomplete filling.

[0085] exist Figure 9 In step S240, if it is determined that the detection value Pr is greater than or equal to the third reference value P3, in step S260, the control unit 500 determines whether the detection value Pr is greater than the fourth reference value P4. In step S260, if it is determined that the detection value Pr is not greater than the fourth reference value P4, in step S270, the control unit 500 pushes the plunger 152 at a second reference speed. That is, during the injection operation, if the detection value Pr is greater than or equal to the third reference value P3 and less than or equal to the fourth reference value P4, the control unit 500 pushes the plunger 152 at a second reference speed.

[0086] In step S260, if it is determined that the detection value Pr is greater than the fourth reference value P4, in step S280, the control unit 500 pushes the plunger 152 at a speed lower than the second reference speed. That is, during the injection operation, if the detection value Pr exceeds the fourth reference value P4, the control unit 500 pushes the plunger 152 at a speed lower than the second reference speed.

[0087] like Figure 11As shown, at time t4, the detection value Pr exceeds the fourth reference value P4. At this time, with the plunger 152 being pushed at the second reference speed, the plastic material is injected into the mold section 160 at a higher pressure than when the detection value Pr is above the third reference value P3 and below the fourth reference value P4. When the plastic material is injected into the mold section 160 at a pressure higher than appropriate, residual stress may remain in the molded article, reducing the strength of the molded article. At time t4, the control unit 500 can suppress the injection of molding material into the mold section 160 at excessive pressure by pushing the plunger 152 at a speed lower than the second reference speed. It should be noted that the residual stress in the molded article is sometimes referred to as residual stress. The change in the detection value Pr at time t3 and time t4 is caused, for example, by changes in the amount and state of the plastic material flowing from the melt section 120 to the connecting hole 146. In addition, there are cases where the detection value Pr varies depending on the shape of the mold cavity Cv of the mold section 160. For example, when the plastic material injected into the mold section 160 passes through the mold cavity Cv with a smaller flow path cross-sectional area, the detection value Pr becomes larger compared to the case where the plastic material passes through the mold cavity Cv with a larger flow path cross-sectional area.

[0088] In step S290, the control unit 500 determines whether the injection operation is complete. If it is determined in step S290 that the injection operation is not complete, the control unit 500 returns the process to step S240 and continues the injection molding process. If it is determined in step S290 that the injection operation is complete, the control unit 500 ends the injection molding process.

[0089] According to the injection molding machine 10 of this embodiment described above, the control unit 500 controls the injection control unit 150 to perform the injection operation based on the detection value Pr detected by the pressure detection unit 200. Therefore, even if the amount or state of the plasticized material generated by the molten section 120 changes, a high injection accuracy of the plasticized material can be maintained. Consequently, the molding accuracy of the molded article is improved.

[0090] Furthermore, in this embodiment, during the injection operation, the speed of pushing the plunger 152 is adjusted based on the detected value Pr. Therefore, high injection accuracy of the plasticizing material can be maintained, and the molding accuracy of the molded article is improved.

[0091] Furthermore, in this embodiment, during the injection operation, the control unit 500 pushes the plunger 152 at a second reference speed when the detected value Pr is above the third reference value P3 and below the fourth reference value P4; when the detected value Pr is less than the third reference value P3, it pushes the plunger 152 at a speed higher than the second reference speed; and when the detected value Pr exceeds the fourth reference value P4, it pushes the plunger 152 at a speed lower than the second reference speed. Therefore, high injection accuracy of the plasticizing material can be maintained, and molded articles can be formed efficiently.

[0092] It should be noted that, in this embodiment, the pressure detection unit 200, similar to that in the first embodiment, detects the pressure of the plasticizing material closer downstream of the connecting hole 146 than the connection between the cylinder 151 and the connecting hole 146. Therefore, during the injection operation, the injection control unit 150 controls the injection by detecting the pressure of the plasticizing material at a position closer to the injection nozzle 156. Consequently, the pressure of the injected plasticizing material is more stable, and the injection accuracy is improved.

[0093] Furthermore, during the injection operation, the control unit 500 pushes the plunger 152 at a second reference speed when the detected value Pr is above the third reference value P3 and below the fourth reference value P4; when the detected value Pr is less than the third reference value P3, it pushes the plunger 152 at a speed higher than the second reference speed; and when the detected value Pr exceeds the fourth reference value P4, it pushes the plunger 152 at a speed lower than the second reference speed. This process is acceptable, and it can also be performed in conjunction with... Figure 9 The injection molding process shown is different. Furthermore, a holding pressure operation may also be included in the injection process.

[0094] C. Third implementation method:

[0095] Figure 12 This is an explanatory diagram showing the schematic structure of the injection molding machine 10c in the third embodiment. In this embodiment, the structure of the molten portion 120c of the injection unit 100c differs from that in the first embodiment. It should be noted that aspects of the injection unit 100c not specifically described are the same as those in the first embodiment.

[0096] The molten section 120c of this embodiment includes a cooling section 210. The cooling section 210 cools the region of the molten section 120c that is closer to the outer periphery of the barrel 140 than the connecting hole 146. Furthermore, the cooling section 210 cools the pressure detection section 200. The cooling section 210 of this embodiment is composed of an annular refrigerant flow path along the circumference of the barrel 140. The cooling section 210 introduces refrigerant into the refrigerant flow path through a refrigerant inlet (not shown) and discharges refrigerant to the outside through a refrigerant outlet (not shown). In this embodiment, a portion of the refrigerant flow path constituting the cooling section 210 is located near the pressure detection section 200, thereby cooling the pressure detection section 200. In other embodiments, for example, the cooling section 210 and the pressure detection section 200 may be connected via a heat suppression section 195, or they may be directly connected. Alternatively, multiple cooling sections 210 may be provided.

[0097] The injection molding machine 10c of the third embodiment described above improves the injection precision of the plasticizing material and the molding precision of the molded article. In particular, in this embodiment, the cooling unit 210 cools the pressure detection unit 200. Therefore, deterioration caused by the heat of the pressure detection unit 200 is suppressed, and the pressure detection precision of the pressure detection unit 200 is improved.

[0098] D. Fourth Implementation Method:

[0099] Figure 13 This is a flowchart illustrating the injection molding process in the fourth embodiment. Alternatively, it can be said that... Figure 13 An example of the control method for the injection molding machine 10 in the fourth embodiment is shown. In the injection molding process of the fourth embodiment, similar to the first embodiment, a metering operation is performed based on the detection value Pr. However, unlike the first embodiment, in the injection molding process of the fourth embodiment, the heating unit 148 is controlled based on the detection value Pr during the metering operation. The structure of the injection molding machine 10 in the fourth embodiment is the same as that in the first embodiment, therefore, description is omitted.

[0100] Steps S310 to S340 and Figure 6 Steps S110 to S130 of the first embodiment shown are the same, so the description is omitted.

[0101] In step S345, the control unit 500 controls the heating unit 148 to reduce its output. That is, in this embodiment, as... Figure 8 As shown at time t1, when the detected value Pr is less than the first reference value P1, the control unit 500 reduces the output of the heating unit 148. As a result, compared to the case where the output of the heating unit 148 is not reduced after time t1, the viscosity of the plasticizing material flowing into the connecting hole 146 increases, and the detected value Pr increases.

[0102] Steps S350 to S370 and Figure 6 Steps S150 to S170 of the first embodiment shown are the same, so the description is omitted.

[0103] In step S375, the control unit 500 controls the heating unit 148 to increase its output. That is, in this embodiment, as... Figure 8 As shown at time t2, when the detected value Pr exceeds the second reference value P2, the control unit 500 increases the output of the heating unit 148. As a result, compared to the case where the output of the heating unit 148 is not increased after time t2, the viscosity of the plasticizing material flowing into the connecting hole 146 decreases, and the detected value Pr decreases.

[0104] Steps S380 and S390 Figure 6 Steps S180 and S190 of the first embodiment shown are the same, so the description is omitted.

[0105] It should be noted that, similar to the second embodiment, the control unit 500 can also control the heating unit 148 based on the detection value Pr during the injection operation. In this case, the control unit 500 may, for example, reduce the output of the heating unit 148 if the detection value Pr is not higher than the third reference value P3, and increase the output of the heating unit 148 if the detection value Pr exceeds the fourth reference value P4. Alternatively, the control unit 500 may, for example, use a value other than the first reference value P1 to the fourth reference value P4 as a reference value and control the heating unit 148 based on the detection value Pr.

[0106] The injection molding machine 10 of the fourth embodiment described above improves the injection precision of the plasticizing material and the molding precision of the molded article. In particular, in this embodiment, the heating section 148 is controlled based on the detection value Pr. Therefore, by stabilizing the plasticizing state of the plasticizing material generated by the molten section 120, the molding precision is improved.

[0107] It should be noted that a heater for heating the plasticized material inside the cylinder 151 can also be provided in the cylinder 151. In this case, the heater can be configured, for example, to be connected to the side of the cylinder 151. The control unit 500 can also control the heater based on the detected value Pr during metering and injection operations. In this case, the plasticization state of the plasticized material inside the cylinder 151 is stable.

[0108] E. Fifth implementation method:

[0109] Figure 14This is an explanatory diagram showing the schematic structure of the injection molding machine 10e in the fifth embodiment. In this embodiment, the structure of the injection unit 100e differs from that in the first embodiment. It should be noted that aspects of the injection unit 100e that are not specifically described are the same as those in the first embodiment.

[0110] The injection unit 100e of this embodiment has a supply flow path 155. The supply flow path 155 is formed on the outside of the barrel 140e to connect the connecting hole 146 to the injection nozzle 156. One end of the supply flow path 155 is connected to the connecting hole 146 of the barrel 140e. The other end of the supply flow path 155 is connected to the injection nozzle 156. The plasticized material generated by the molten portion 120e flows to the injection nozzle 156 via the connecting hole 146 and the supply flow path 155.

[0111] The injection control unit 150e in this embodiment, like that in the first embodiment, includes a cylinder 151e, a plunger 152e, and a plunger drive unit 153e. For example... Figure 14 As shown, in this embodiment, the cylinder body 151e is connected to the supply flow path 155, rather than to the connecting hole 146. The plunger 152e moves inside the cylinder body 151e. The plunger 152e is driven by a plunger drive unit 153e, which is composed of a motor, gears, etc. The plunger drive unit 153e is controlled by the control unit 500.

[0112] Similar to the first embodiment, the injection control unit 150, under the control of the control unit 500, slides the plunger 152 within the cylinder 151, thereby performing metering and injection operations. In this embodiment, the metering operation refers to the operation of introducing plasticized material from the supply flow path 155 into the cylinder 151 by moving the plunger 152 in the -X direction away from the supply flow path 155, and performing metering within the cylinder 151. The injection operation refers to the operation of injecting plasticized material from the cylinder 151 into the molding die via the injection nozzle 156 by moving the plunger 152 in the +X direction closer to the supply flow path 155.

[0113] Figure 15 This is an explanatory diagram showing the schematic structure of the pressure detection unit 200e. Unlike the first embodiment, the pressure detection unit 200e detects the pressure of the plasticizing material in the supply flow path 155, rather than the pressure of the plasticizing material in the connecting hole 146.

[0114] The pressure detection unit 200e is supported by the support unit 190e. In this embodiment, the support unit 190e is positioned differently from that in the first embodiment. Specifically, in this embodiment, the recess 191 is not provided on the barrel 140e of the melting section 120e, and the support unit 190e is grounded to the lower part of the barrel 140e.

[0115] Similar to the first embodiment, the support portion 190e also has a heat suppression portion 195e. The heat suppression portion 195e is disposed between the pressure detection portion 200e and the molten portion 120e. The heat suppression portion 195e has multiple feet 196e. Multiple spaces 197e are formed between the molten portion 120e and the support portion 190e through the multiple feet 196e. Through the air within these spaces 197e, the heat suppression portion 195e suppresses heat conduction from the molten portion 120e to the pressure detection portion 200e.

[0116] In this embodiment, the pressure detection unit 200e detects the pressure of the plasticizing material within the supply flow path 155 via a rod 201e. The rod 201e is a shaft-shaped component with a flange 202e. The rod 201e is disposed along the X direction within a through hole 143e communicating with the supply flow path 155. The through hole 143 is disposed along the X direction. The front end portion 203e, which is one end of the rod 201e, is disposed facing the interior of the supply flow path 155. The rear end portion 204e, which is the other end of the rod 201e, is disposed opposite the pressure detection unit 200e. The flange 202e is formed midway along the X direction of the rod 201e. The flange 202e is disposed in the -X direction of the through hole 143e to restrict the movement of the rod 201e in the +X direction.

[0117] The rod 201e is subjected to pressure from the plasticizing material in the supply flow path 155 via its front end 203e, and the pressure is transmitted to the pressure detection unit 200e via its rear end 204e. The pressure detection unit 200e detects the pressure transmitted from the rod 201e. It should be noted that, similar to the first embodiment, the pressure detection unit 200 in this embodiment is composed of a pressure sensor with a crystal.

[0118] In this embodiment, the control unit 500 executes and Figure 6 The injection molding process shown in the first embodiment is the same as that in the injection molding process. That is, the control unit 500 controls the injection control unit 150e to perform the metering operation based on the detection value Pr of the pressure detection unit 200e.

[0119] Figure 16 This is an explanatory diagram illustrating the metering operation in this embodiment. During the metering operation, by pulling the plunger 152e, the supply flow path 155 is filled with plasticizing material, and the plasticizing material is guided into the cylinder 151e. The pressure detection unit 200e detects the pressure of the plasticizing material in the supply flow path 155 during this metering operation.

[0120] According to the injection molding machine 10e of this embodiment described above, the control unit 500 controls the injection control unit 150e to perform metering operations based on the detection value Pr detected by the pressure detection unit 200e. Therefore, even if the amount or state of the plasticized material generated by the molten section 120e changes, high metering accuracy can be maintained. Consequently, the injection accuracy of the plasticized material is improved, and the molding accuracy of the molded article is improved.

[0121] It should be noted that the control unit 500 can also be connected with... Figure 9 Similarly, in the injection molding process of the second embodiment shown, the injection control unit 150e is controlled based on the detection value Pr to perform the injection operation. Figure 17 This is an explanatory diagram illustrating the injection operation in this embodiment. After the metering operation, by pushing the plunger 152, the plastic material in the cylinder 151 is conveyed to the injection nozzle 156 via the connecting hole 146 and the supply flow path 155, and then injected into the mold cavity Cv of the mold section 160 via the injection nozzle 156. The pressure detection unit 200e can also detect the pressure of the plastic material in the supply flow path 155 during this injection operation. In this case, the injection accuracy of the plastic material is improved, and the molding accuracy of the molded article is improved.

[0122] Control unit 500 can also be connected with Figure 13 Similarly, in the injection molding process of the fourth embodiment shown, the heating section 148 is controlled based on the detection value Pr during the metering operation. Additionally, the heating section 148 can also be controlled based on the detection value Pr during the injection operation. In this case, the injection accuracy of the plasticizing material is improved, and the molding accuracy of the molded article is improved.

[0123] F. Sixth Implementation Method:

[0124] Figure 18 This is an explanatory diagram showing the schematic structure of the injection molding machine 10f in the sixth embodiment. In this embodiment, the structure of the pressure detection unit 200f of the injection unit 100f differs from that of the first embodiment. It should be noted that aspects of the injection unit 100f not specifically described are the same as those in the first embodiment.

[0125] In this embodiment, the pressure detection unit 200f differs from the first embodiment in that it detects the pressure of the plasticizing material upstream of the connecting hole 146, which is closer to the connection between the cylinder 151 and the connecting hole 146. Specifically, the pressure detection unit 200f detects the pressure of the plasticizing material via a rod 201 positioned further downstream of the check valve 149 and further upstream of the connection between the cylinder 151 and the connecting hole 146. It should be noted that the injection unit 100f in this embodiment does not have a support portion 190. The pressure detection unit 200f is fixed to the barrel 140 by a fixing portion (not shown).

[0126] The injection molding machine 10f of the sixth embodiment described above improves the injection precision of the plasticizing material and the molding precision of the molded article. In particular, in this embodiment, the pressure detection unit 200f detects the pressure of the plasticizing material upstream of the connecting hole 146, which is closer to the connection between the cylinder 151 and the connecting hole 146. Therefore, the injection control unit 150 controls the injection process by detecting the pressure of the plasticizing material near the melt section 120 during metering and injection operations. Consequently, the linkage between the injection control unit 150 and the melt section 120 is improved.

[0127] G. Other implementation methods:

[0128] (G-1) In the above embodiment, the control unit 500 adjusts the speed of pulling the plunger 152 based on the detection value Pr during the metering operation. Alternatively, the control unit 500 may also adjust the amount of pulling the plunger 152 based on the detection value Pr during the metering operation. Specifically, the position of the plunger 152 when the metering operation is completed may also be controlled based on the detection value Pr.

[0129] (G-2) In the above embodiment, during the metering operation, the control unit 500 pulls the plunger 152 at a first reference speed when the detected value Pr is above the first reference value P1 and below the second reference value P2; when the detected value Pr is less than the first reference value P1, it pulls the plunger 152 at a speed lower than the first reference speed; and when the detected value Pr exceeds the second reference value P2, it pulls the plunger 152 at a speed higher than the first reference speed. Alternatively, the control unit 500 may determine, for example, whether the detected value Pr is above a reference value, and control the injection control unit 150 based on this determination result.

[0130] (G-3) In the above embodiment, the control unit 500 adjusts the speed of pushing the plunger 152 based on the detection value Pr during the injection operation. Alternatively, the control unit 500 may also adjust the position at which the plunger 152 begins to be pushed based on the detection value Pr during the injection operation.

[0131] (G-4) In the above embodiment, during the injection operation, the control unit 500 pushes the plunger 152 at a second reference speed when the detected value Pr is above the third reference value P3 and below the fourth reference value P4; when the detected value Pr is less than the third reference value P3, it pushes the plunger 152 at a speed higher than the second reference speed; and when the detected value Pr exceeds the fourth reference value P4, it pushes the plunger 152 at a speed lower than the second reference speed. Alternatively, the control unit 500 may determine, for example, whether the detected value Pr is above a reference value, and control the injection control unit 150 based on this determination result.

[0132] (G-5) In the above embodiment, a heat suppression section 195 is provided between the pressure detection section 200 and the molten section 120. In contrast, the heat suppression section 195 may not be provided between the pressure detection section 200 and the molten section 120.

[0133] (G-6) In the above embodiment, the auger 130 has a retention suppression portion 138 in the central portion 137. Alternatively, the auger 130 may not have the retention suppression portion 138.

[0134] (G-7) In the above embodiment, the pressure detection unit 200 detects the pressure of the plasticizing material via the rod 201. Alternatively, the pressure detection unit 200 may also detect the pressure of the plasticizing material without using the rod 201.

[0135] (G-8) In the above embodiment, the pressure detection unit 200 detects the pressure of the plasticizing material throughout the entire injection molding process. Alternatively, the pressure detection unit 200 may detect the pressure of the plasticizing material only in a portion of the injection molding process. For example, the pressure detection unit 200 may detect pressure during the metering operation and the injection operation, but not during other processes.

[0136] H. Other methods:

[0137] This disclosure is not limited to the embodiments described above, and can be implemented in various ways without departing from its spirit. For example, this disclosure can also be implemented in the following ways. In order to solve part or all of the technical problems of this disclosure, or to achieve part or all of the effects of this disclosure, the technical features in the above embodiments corresponding to the technical features in the various methods described below can be appropriately replaced or combined. In addition, if a technical feature is not described as a necessary feature in this specification, it can be appropriately deleted.

[0138] (1) According to a first aspect of this disclosure, an injection molding machine is provided. The injection molding machine comprises: a melting section having a auger and a barrel, the auger rotating about a rotation axis and having a groove forming surface, the barrel having a counter surface opposite to the groove forming surface and having a connecting hole on the counter surface, the melting section plasticizing material supplied between the auger and the barrel to generate a plasticized material, and causing the plasticized material to flow out from the connecting hole; a heating section for heating the melting section; an injection nozzle communicating with the connecting hole; an injection control section having a cylinder connected to the connecting hole and a plunger moving within the cylinder; a pressure detection section for detecting the pressure of the plasticized material within the connecting hole; and a control section. The control unit controls the injection control unit, and the control unit performs at least one of a metering operation and an injection operation based on the detection value detected by the pressure detection unit. In the metering operation, the plastic material in the communicating hole is metered in the cylinder by moving the plunger away from the communicating hole. In the injection operation, the plastic material in the cylinder is injected into the molding die via the injection nozzle by moving the plunger towards the communicating hole.

[0139] In this way, even if the amount and state of the plasticized material generated from the molten part change, a high injection precision of the plasticized material can be maintained. Therefore, the molding precision of the molded article is improved.

[0140] (2) Alternatively, in the injection molding machine described above, the control unit adjusts the speed at which the plunger moves away from the communicating hole during the metering operation based on the detected value. In this manner, high metering accuracy of the plasticizing material can be maintained, and the injection accuracy of the plasticizing material is improved.

[0141] (3) Alternatively, in the injection molding machine described above, when the detected value is above a first reference value and below a second reference value greater than the first reference value, the control unit moves the plunger at a first reference speed; when the detected value is less than the first reference value, the control unit moves the plunger at a speed lower than the first reference speed; and when the detected value exceeds the second reference value, the control unit moves the plunger at a speed higher than the first reference speed. According to this method, high metering accuracy of the plasticizing material can be maintained, and the plasticizing material can be metered efficiently.

[0142] (4) Alternatively, in the injection molding machine described above, the control unit can adjust the speed at which the plunger moves toward the communicating hole based on the detection value during the injection operation. In this way, the injection accuracy of the plasticized material is improved.

[0143] (5) Alternatively, in the injection molding machine described above, when the detected value is above the third reference value and below the fourth reference value, the control unit moves the plunger at a second reference speed; when the detected value is below the third reference value, the control unit moves the plunger at a speed higher than the second reference speed; and when the detected value exceeds the fourth reference value, the control unit moves the plunger at a speed lower than the second reference speed. According to this method, high injection accuracy of the plasticizing material can be maintained, and the molded article can be molded efficiently.

[0144] (6) Alternatively, in the injection molding machine described above, a heat suppression section is provided between the pressure detection section and the molten section to suppress heat conduction from the molten section to the pressure detection section. In this manner, the deterioration of the pressure detection section caused by heat transfer from the molten section is suppressed, and the flexibility in the placement of the pressure detection section is increased.

[0145] (7) Alternatively, in the injection molding machine described above, the injection molding machine includes a cooling section that cools the region of the molten portion closer to the outer periphery of the barrel than the communicating hole in the direction along the groove forming surface, and the cooling section also cools the pressure sensing section. In this manner, deterioration caused by heat in the pressure sensing section is suppressed, and the pressure sensing accuracy of the pressure sensing section is improved.

[0146] (8) Alternatively, in the injection molding machine described above, the pressure detection unit detects the pressure of the plastic material closer to the downstream of the connecting hole than the connection between the cylinder and the connecting hole. In this manner, the injection control unit controls the metering and injection operation by detecting the pressure of the plastic material at a position closer to the injection nozzle. Therefore, the amount and pressure of the injected plastic material are more stable, and the injection accuracy of the plastic material is improved.

[0147] (9) Alternatively, in the injection molding machine described above, the auger has a retention-inhibiting portion protruding toward the connecting hole at the center of the groove forming surface. In this manner, the amount and state of the plasticized material conveyed from the molten portion to the injection nozzle via the connecting hole are stable, and the injection accuracy of the plasticized material is improved.

[0148] (10) Alternatively, in the injection molding machine described above, the control unit controls the heating unit based on the detected value. In this manner, the heating unit is controlled based on the detected value. Therefore, the plasticizing state of the plasticizing material is stable, thereby improving the molding accuracy of the molded article.

[0149] (11) According to a second aspect of this disclosure, an injection molding machine is provided. The injection molding machine comprises: a melting section having a auger and a barrel, the auger rotating about a rotation axis and having a groove forming surface, the barrel having a counter surface opposite to the groove forming surface and having a connecting hole on the counter surface, the melting section plasticizing material supplied between the auger and the barrel to generate a plasticized material, and the plasticized material flowing out from the connecting hole; a supply flow path communicating with the connecting hole; a heating section for heating the melting section; an injection nozzle communicating with the supply flow path; an injection control section having a cylinder connected to the supply flow path and a plunger moving within the cylinder; a pressure detection section for detecting the pressure of the plasticized material within the supply flow path; and a control section. The control unit controls the injection control unit, and the control unit performs at least one of a metering operation and an injection operation based on the detection value detected by the pressure detection unit. In the metering operation, the plasticizing material in the supply flow path is metered in the cylinder by moving the plunger away from the supply flow path. In the injection operation, the plasticizing material in the cylinder is injected into the molding die via the injection nozzle by moving the plunger towards the supply flow path.

[0150] In this way, even if the amount and state of the plasticized material generated from the molten part change, a high injection precision of the plasticized material can be maintained. Therefore, the molding precision of the molded article is improved.

[0151] (12) According to a third aspect of this disclosure, a control method for an injection molding machine is provided. In this control method for an injection molding machine, the injection molding machine comprises: a melting section having a auger and a barrel, the auger rotating about a rotation axis and having a groove forming surface having a groove, the barrel having a counter surface opposite to the groove forming surface and having a connecting hole on the counter surface, the melting section plasticizing material supplied between the auger and the barrel to generate a plasticized material, and causing the plasticized material to flow out from the connecting hole; a heating section for heating the melting section; an injection nozzle communicating with the connecting hole; and an injection control section having a cylinder connected to the connecting hole and a plunger moving within the cylinder. The pressure of the plasticizing material within the connecting hole is detected, and based on the detected pressure value, the injection control unit is controlled to perform at least one of a metering operation and an injection operation. In the metering operation, the plasticizing material within the connecting hole is metered in the cylinder by moving the plunger away from the connecting hole. In the injection operation, the plasticizing material in the cylinder is injected via the injection nozzle by moving the plunger towards the connecting hole.

[0152] In this way, even if the amount and state of the plasticized material generated from the molten part change, a high injection precision of the plasticized material can be maintained. Therefore, the molding precision of the molded article is improved.

[0153] This disclosure is not limited to the injection molding machine and its control method described above, and can be implemented in various ways. For example, it can be implemented through methods such as methods for manufacturing molded articles.

Claims

1. An injection molding machine, characterized in that, have: The melting section includes a spiral member and a barrel. The spiral member rotates around a rotation axis and has a groove forming surface. The barrel has a counter surface opposite to the groove forming surface and a connecting hole is provided on the counter surface. The melting section plasticizes the material supplied between the spiral member and the barrel to generate a plasticized material, and the plasticized material flows out from the connecting hole. A heating section heats the molten section; The injection nozzle is connected to the communicating hole; An injection control unit has a cylinder including the communicating hole and a flow path connected to the plasticizing material, and a plunger moving within the cylinder. A rod is disposed in the flow path within a hole at a position different from the position where the cylinder body is connected; The pressure detection unit detects the pressure of the plasticizing material in the flow path via the rod; as well as Control Department The control unit controls the injection control unit to perform at least one of a metering operation and an injection operation based on the detection value detected by the pressure detection unit. In the metering operation, the plasticizing material within the flow path is metered within the cylinder by moving the plunger away from the flow path. In the injection operation, by moving the plunger toward the flow path, the plasticizing material in the cylinder is injected into the molding die via the injection nozzle.

2. The injection molding machine according to claim 1, characterized in that, Based on the detected value, the control unit adjusts the speed at which the plunger moves away from the flow path during the metering operation, and adjusts the speed at which the plunger moves closer to the flow path during the injection operation.

3. The injection molding machine according to claim 2, characterized in that, During the metering operation, when the detected value is above a first reference value and below a second reference value greater than the first reference value, the control unit moves the plunger away from the flow path at a first reference speed. When the detected value is less than the first reference value, the control unit moves the plunger away from the flow path at a speed lower than the first reference speed. When the detected value exceeds the second reference value, the control unit moves the plunger away from the flow path at a speed higher than the first reference speed. During the injection operation, if the detected value is above a third reference value and below a fourth reference value that is greater than the third reference value, the control unit moves the plunger toward the flow path at a second reference speed. If the detected value is less than the third reference value, the control unit moves the plunger toward the flow path at a speed higher than the second reference speed. If the detected value exceeds the fourth reference value, the control unit moves the plunger toward the flow path at a speed lower than the second reference speed.

4. The injection molding machine according to claim 1, characterized in that, A heat suppression section is provided between the pressure detection section and the melting section to suppress heat conduction from the melting section to the pressure detection section.

5. The injection molding machine according to claim 1, characterized in that, The injection molding machine includes a cooling section that cools a region of the molten portion closer to the outer periphery of the barrel than the connecting hole, along the direction of the groove forming surface. The cooling unit cools the pressure detection unit.

6. The injection molding machine according to claim 1, characterized in that, The spiral component has a retention-inhibiting portion protruding toward the connecting hole at the center of the groove forming surface.

7. The injection molding machine according to claim 1, characterized in that, The pressure detection unit includes a pressure sensor, and the pressure sensor has a piezoelectric element.

8. The injection molding machine according to claim 1, characterized in that, The rod is a shaft-shaped component with a flange.

9. The injection molding machine according to claim 1, characterized in that, The rod is positioned on the opposite side of the cylinder, across the flow path.

10. The injection molding machine according to claim 1, characterized in that, The control unit performs at least one of the metering operation and the injection operation based on the detection value, and controls the heating unit based on the detection value.

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