CN115782104A

CN115782104A - Injection molding machine

Info

Publication number: CN115782104A
Application number: CN202211088825.4A
Authority: CN
Inventors: 雷磊; 山口毅秀; 中村彻
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2015-09-29
Filing date: 2016-09-29
Publication date: 2023-03-14
Also published as: TW201711825A; CN106903854A; JP6552933B2; JP2017065016A; TWI615261B; KR20170038159A

Abstract

The invention provides an injection molding machine capable of stabilizing quality of a molded product. The injection molding machine comprises: a detector that detects a flow of the molding material in the mold device; and a control device for controlling a compression operation of compressing the molding material in a cavity space in the mold device according to a detection result of the detector.

Description

Injection molding machine

The invention is a divisional application with the name of "injection molding machine" and the Chinese patent application number 201610865533.5 filed by the applicant on 2016, 9, month 29.

Technical Field

The present application claims priority based on japanese patent application No. 2015-191823, filed on 9/29/2015. The entire contents of this Japanese application are incorporated by reference into this specification.

The present invention relates to an injection molding machine.

Background

The injection molding machine described in patent document 1 performs 1 injection step of injecting the molten resin accumulated on the tip side of the screw into the mold by moving the screw in the heating cylinder forward, and starts a compression step of applying a compression pressure to the resin in the mold in the middle of the 1 injection step. The injection molding machine starts a compression process when the actual measurement advance distance of the screw reaches a preset value.

Patent document 1: japanese patent laid-open publication No. 2002-113753

Conventionally, the influence of variation in injection period in a step other than the compression step is expanded by the compression step, and variation in quality of the molded product is increased in some cases.

Disclosure of Invention

The present invention has been made in view of the above problems, and a main object thereof is to provide an injection molding machine capable of stabilizing the quality of a molded product.

In order to solve the above problem, according to an aspect of the present invention, there is provided an injection molding machine including:

a detector for detecting a flow of the molding material in the mold device; and

and a control device for controlling a compression operation of compressing the molding material in a cavity space in the mold device according to a detection result of the detector.

Effects of the invention

According to an aspect of the present invention, there is provided an injection molding machine capable of stabilizing the quality of a molded product.

Drawings

Fig. 1 is a diagram showing a state at the end of mold opening of an injection molding machine according to an embodiment.

Fig. 2 is a diagram showing a state of the injection molding machine according to the embodiment when mold clamping is performed.

Fig. 3 is a diagram showing a state in the mold apparatus before the start of the compression operation of the injection molding machine according to the embodiment.

Fig. 4 is a diagram showing a state in the mold apparatus after the compression operation of the injection molding machine according to the embodiment is completed.

Fig. 5 is a diagram showing a state of the injection molding machine according to the modification at the time of mold clamping.

In the figure: 30-mould device, 32-fixed mould, 33-movable mould, 34-cavity space, 36-compression part, 37-detector, 40-injection device, 41-cylinder, 42-nozzle, 43-screw, 50-intermediate device, 60-ejection device and 90-control device.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings, and the same or corresponding components are denoted by the same or corresponding reference numerals in the drawings, and description thereof will be omitted.

Fig. 1 is a diagram showing a state at the end of mold opening of an injection molding machine according to an embodiment. Fig. 2 is a diagram showing a state of the injection molding machine according to the embodiment when mold clamping is performed. In fig. 1 and 2, for convenience of explanation, the flow path of the molding material in the mold device 30 is simplified.

For example, as shown in fig. 1 and 2, the injection molding machine includes a frame Fr, a mold clamping device 10, an injection device 40, an intermediate device 50, an ejector device 60, and a control device 90. The intermediate device 50 may be included in the mold device 30 or may not be included in the injection molding machine.

First, the mold apparatus 10, the intermediate apparatus 50, and the ejector apparatus 60 will be described. In the description of the mold clamping apparatus 10 and the like, the moving direction of the movable platen 13 when the mold is closed (the right direction in fig. 1 and 2) is set to the front, and the moving direction of the movable platen 13 when the mold is opened (the left direction in fig. 1 and 2) is set to the rear.

The mold clamping device 10 closes, clamps, and opens the mold of the mold device 30. The mold clamping device 10 includes a fixed platen 12, a movable platen 13, a support platen 15, a tie bar 16, a toggle mechanism 20, a mold clamping motor 21, and a motion conversion mechanism 25.

The fixed platen 12 is fixed to the frame Fr. A fixed mold 32 is attached to a surface of the fixed platen 12 facing the movable platen 13.

The movable platen 13 is movable along a guide (e.g., a guide rail) 17 laid on the frame Fr, and is movable forward and backward with respect to the fixed platen 12. A movable mold 33 is attached to a surface of the movable platen 13 facing the fixed platen 12 via an intermediate device 50.

The movable platen 13 is moved forward and backward with respect to the fixed platen 12 to perform mold closing, mold clamping, and mold opening. The fixed die 32 and the movable die 33 constitute a die apparatus 30.

The support platen 15 is connected to the fixed platen 12 with a gap therebetween, and is mounted on the frame Fr so as to be movable in the mold opening and closing direction. The support platen 15 may be movable along a guide laid on the frame Fr. The guide member supporting the platen 15 may be common to the guide member 17 of the movable platen 13.

In the present embodiment, the fixed platen 12 is fixed to the frame Fr, and the supporting platen 15 is movable in the mold opening and closing direction with respect to the frame Fr, but the supporting platen 15 may be fixed to the frame Fr, and the fixed platen 12 may be movable in the mold opening and closing direction with respect to the frame Fr.

The tie bar 16 connects the fixed platen 12 and the support platen 15 with a gap therebetween. A plurality of tie bars 16 may be used. Each tie bar 16 extends in parallel with the mold opening and closing direction and in accordance with the mold clamping force. At least 1 tie bar 16 is provided with a clamping force detector 18. The mold clamping force detector 18 may be of a strain gauge type, and detects the mold clamping force by detecting the strain of the tie bar 16.

The mold clamping force detector 18 is not limited to the strain gauge type, and may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, or the like, and the attachment position thereof is not limited to the tie bar 16.

The toggle mechanism 20 is disposed between the movable platen 13 and the supporting platen 15. The toggle mechanism 20 is constituted by a crosshead 20a, a plurality of

links

20b, 20c, and the like. One of the links 20b is swingably attached to the movable platen 13, and the other link 20c is swingably attached to the support platen 15. The

links

20b and 20c are connected by a pin or the like so as to be extendable and retractable. By advancing and retracting the crosshead 20a, the plurality of

links

20b, 20c extend and contract, and the movable platen 13 advances and retracts with respect to the supporting platen 15.

The mold clamping motor 21 is attached to the support platen 15, and advances and retracts the movable platen 13 by advancing and retracting the cross head 20 a. A motion conversion mechanism 25 that converts the rotational motion of the mold clamping motor 21 into a linear motion and transmits the linear motion to the crosshead 20a is provided between the mold clamping motor 21 and the crosshead 20 a. The motion conversion mechanism 25 is constituted by, for example, a ball screw mechanism. The position and speed of the crosshead 20a are detected by an encoder 21a of the mold clamping motor 21, for example.

The operation of the mold clamping device 10 is controlled by a control device 90. The controller 90 controls the mold closing process, the mold opening process, and the like.

In the mold closing step, the movable platen 13 is moved forward by driving the mold clamping motor 21, and the movable mold 33 is brought into contact with the fixed mold 32. The compression member 36 is disposed on the movable mold 33 side, and the compression member 36 is movable forward and backward in the mold device 30.

In the mold clamping step, the mold clamping motor 21 is further driven to generate a mold clamping force. During mold clamping, a cavity space 34 is formed between the compression member 36 disposed on the movable mold 33 side and the fixed mold 32, and the cavity space 34 is filled with a liquid molding material. Within the cavity space 34, the molding material is compressed by the compression member 36. The molding material in the cavity space 34 is solidified to form a molded product.

In the mold opening step, the movable platen 13 is retracted by driving the mold clamping motor 21, and the movable mold 33 is separated from the fixed mold 32.

Further, the mold clamping device 10 of the present embodiment includes the mold clamping motor 21 as a driving source, but may include a hydraulic cylinder instead of the mold clamping motor 21. The mold clamping device 10 may have a linear motor for opening and closing the mold, or may have an electromagnet for clamping the mold.

The intermediate device 50 is disposed between the movable mold 33 and the movable platen 13. The intermediate device 50 has, for example, a block 51. The rear end portion of the compression member 36 is inserted into the internal space 52 of the block body 51.

The ejector 60 ejects the molded product from the mold apparatus 30 after the mold is opened. The ejector 60 includes, for example, an ejector motor 61, a motion conversion mechanism 62, and an ejector rod 63.

The ejector motor 61 is mounted on the rear surface of the movable platen 13. The ejection motor 61 has an encoder 61a. The encoder 61a detects a rotation angle of the output shaft of the ejector motor 61, and outputs a signal indicating the rotation angle to the control device 90.

The motion conversion mechanism 62 converts the rotational motion of the ejector motor 61 into the linear motion of the ejector rod 63. The motion conversion mechanism 62 is constituted by, for example, a ball screw mechanism or the like.

The ejector rod 63 is movable forward and backward in the through hole of the movable platen 13. The front end of the ejector rod 63 contacts the rear end surface of the ejector plate 64.

The ejector plate 64 is movable forward and backward in the internal space 52 of the block 51. The front end surface of the ejector plate 64 contacts the rear end portion of the compression member 36.

The ejector motor 61 is driven to advance the ejector rod 63, thereby advancing the compression member 36. Then, the ejector motor 61 is driven to retract the ejector rod 63, thereby retracting the compression member 36.

The ejector 60 functions as a driving device for the compression member 36. The compression member 36 serves two purposes: (1) compression of the molding material within the mold apparatus 30; (2) ejecting the molded product from the mold device 30.

Next, the injection device 40 will be explained. In the explanation of the injection device 40, unlike the explanation of the mold clamping device 10, the moving direction of the screw 43 during filling (the left direction in fig. 1 and 2) is assumed to be the front side, and the moving direction of the screw 43 during metering (the right direction in fig. 1 and 2) is assumed to be the rear side.

The injection device 40 is provided on a slide Sb which can advance and retreat with respect to the frame Fr, and can advance and retreat with respect to the mold device 30. The injection device 40 is in contact with the mold device 30, and fills the mold device 30 with the molding material.

The injection device 40 includes, for example, a cylinder 41, a nozzle 42, a screw 43, a metering motor 45, an injection motor 46, and a pressure detector 47.

The cylinder 41 heats the molding material supplied from the supply port 41a to the inside. The supply port 41a is formed in the rear of the cylinder 41. A heating source such as a heater is provided on the outer periphery of the cylinder 41.

The nozzle 42 is provided at the front end of the cylinder 41 and is pressed against the die apparatus 30.

The screw 43 is disposed rotatably and movably forward and backward in the cylinder 41.

The metering motor 45 rotates the screw 43, thereby feeding the molding material forward along the spiral groove of the screw 43. The molding material is gradually melted by heat from the cylinder 41 while being sent forward. The screw 43 is retracted as the liquid molding material is fed forward of the screw 43 and accumulated in the front of the cylinder 41.

The injection motor 46 advances and retracts the screw 43. The injection motor 46 advances the screw 43 to inject the liquid molding material accumulated in front of the screw 43 from the cylinder 41 and fill the molding device 30 with the molding material. Thereafter, the injection motor 46 presses the screw 43 forward, thereby applying pressure to the molding material in the mold device 30. The molding material of the insufficient portion can be replenished. A motion conversion mechanism that converts the rotational motion of the injection motor 46 into the linear motion of the screw 43 is provided between the injection motor 46 and the screw 43.

The pressure detector 47 is disposed between the injection motor 46 and the screw 43, for example, and detects the pressure applied to the screw 43 from the molding material, the back pressure applied to the screw 43, and the like. The pressure applied to the screw 43 from the molding material corresponds to the pressure applied to the molding material from the screw 43.

The action of the injection means 40 is controlled by control means 90. The controller 90 controls the filling process, the pressure maintaining process, the metering process, and the like.

In the filling step, the injection motor 46 is driven to advance the screw 43 at a predetermined speed, and the liquid molding material accumulated in front of the screw 43 is filled into the mold device 30. The position and speed of the screw 43 are detected, for example, by an encoder 46a of the injection motor 46. When the position of the screw 43 reaches a predetermined position, the filling process is switched to the pressure holding process (so-called V/P switching). The set speed of the screw 43 can be changed according to the position and time of the screw 43.

In the filling step, after the position of the screw 43 reaches a predetermined position, the screw 43 may be temporarily stopped at the predetermined position, and then the V/P switching may be performed. Instead of stopping the screw 43, the screw 43 may be advanced at a very low speed or retracted at a very low speed before the V/P switching. When any of the stop, the slight-speed advance, and the slight-speed retreat is performed, the molding material flows mainly by the residual pressure or the like, so that the peak pressure of the molding material can be reduced, and the generation of burrs can be suppressed.

In the pressure retaining step, the screw 43 is pressed forward at a set pressure by driving the injection motor 46, and pressure is applied to the molding material in the mold device 30. The molding material of the insufficient portion can be replenished. The pressure of the molding material is detected by, for example, a pressure detector 47. In the pressure retaining step, the molding material in the mold device 30 is gradually cooled, and at the end of the pressure retaining step, the entrance of the cavity space 34 is closed by the solidified molding material. This state is called a gate seal (gate seal) and prevents the molding material from flowing backward from the cavity space 34. After the pressure maintaining step, the cooling step is started. In the cooling step, the molding material in the cavity space 34 is solidified. In order to shorten the molding cycle, the metering step may be performed during the cooling step.

In the metering step, the metering motor 45 is driven to rotate the screw 43 at a predetermined rotation speed, and the molding material is fed forward along the spiral groove of the screw 43. With this, the molding material gradually melts. The screw 43 moves backward as the liquid molding material is fed forward of the screw 43 and accumulated in the front of the cylinder 41. The rotational speed of the screw 43 is detected by an encoder 45a of the metering motor 45, for example.

In the metering step, the injection motor 46 is driven to apply a set back pressure to the screw 43 in order to restrict the screw 43 from rapidly moving backward. The back pressure applied to the screw 43 is detected by, for example, a pressure detector 47. When the screw 43 is retracted to a predetermined position and a predetermined amount of the molding material is accumulated in front of the screw 43, the metering step is terminated.

As shown in fig. 1 and 2, the control device 90 includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The controller 90 controls the mold clamping unit 10, the injection unit 40, the ejector unit 60, and the like by causing the CPU91 to execute a program stored in the storage medium 92.

Fig. 3 is a diagram showing a state in the mold apparatus before the start of the compression operation of the injection molding machine according to the embodiment. The direction of the arrows in fig. 3 indicates the direction of flow of the molding material. Fig. 4 is a diagram showing a state in the mold apparatus after the compression operation of the injection molding machine according to the embodiment is completed. The arrow direction in fig. 4 indicates the compression direction by the compression member 36.

The control device 90 controls a compression operation (hereinafter, simply referred to as "compression operation") for compressing the molding material M in the cavity space 34. The compression operation is performed by advancing the compression member 36, for example.

As shown in fig. 3 and 4, the start of the compression operation may be performed during the filling process, or may be performed before the flow front end of the molding material reaches the end of the flow path. The compression operation may be completed substantially simultaneously with the completion of the filling step, or may be completed substantially simultaneously with the time when the flow front end of the molding material reaches the end point of the flow path.

The start time of the compression operation is not particularly limited. For example, the start of the compression operation may be performed after the start of the pressure holding step. Similarly, the end time of the compression operation is not particularly limited. For example, the end of the compression operation may be before the flow front end of the molding material reaches the end point of the flow path, or after the flow front end of the molding material reaches the end point of the flow path.

A detector 37 for detecting the flow of the molding material M in the mold apparatus 30 is used for the control of the compression operation. The number of detectors 37 is 1 in fig. 3 and 4, but may be plural. The plurality of detectors 37 may be provided at intervals along the flow path of the molding material M.

The detector 37 detects that the molding material M reaches a predetermined position. For example, the detector 37 detects that the flow front end of the molding material reaches a predetermined position. In addition, detector 37 may detect a prescribed amount of molding material to a prescribed location (e.g., cavity space 34).

As the detector 37, for example, a temperature sensor or a pressure sensor is used. Both a temperature sensor and a pressure sensor can be used as the detector 37.

When the molding material M reaches the position where the temperature sensor is installed or the vicinity thereof, the temperature of the molding material M is higher than the temperature of the mold device 30, and thus the measurement value of the temperature sensor increases. The molding material M can be detected to reach a predetermined position based on the rise of the measurement value of the temperature sensor. For example, when the measured value of the temperature sensor exceeds the set value, it is considered that the molding material M has reached the installation position of the temperature sensor or the vicinity thereof. Alternatively, when the time differential value of the measurement value of the temperature sensor exceeds the set value, it is determined that the molding material M has reached the installation position of the temperature sensor or its vicinity.

When the molding material M reaches the installation position of the pressure sensor, the pressure of the molding material M acts on the pressure sensor, and thus the measurement value of the pressure sensor increases. The arrival of the molding material M at the predetermined position can be detected from the rise of the measurement value of the pressure sensor. For example, when the measured value of the pressure sensor exceeds the set value, it is determined that the molding material M has reached the installation position of the pressure sensor. Alternatively, when the time differential value of the measurement value of the pressure sensor exceeds the set value, it is determined that the molding material M has reached the installation position of the pressure sensor.

As the detector 37, a pressure sensor 66 that detects a pressure acting on a member performing a compression operation, a position sensor 65 that detects a position of a member performing a compression operation, and the like can be used. This is because the member performing the compression operation is pressed when the molding material M reaches the cavity space 34. Examples of the member performing the compression operation include the compression member 36, the ejector rod 63, and the ejector plate 64.

In the present embodiment, the member performing the compression operation also serves as the ejection member, but the member performing the compression operation and the ejection member may be provided separately. In this case, as the detector 37, a pressure sensor for detecting a pressure applied to the ejection member and a position sensor for detecting a position of the ejection member may be used. This is because the ejection member is pressed when the molding material M reaches the cavity space 34.

The control device 90 controls the compression operation based on the detection result of the detector 37. By adjusting the compression operation according to the filling state of the molding material in the mold device 30, it is possible to absorb variations in steps other than the compression step (e.g., the metering step and the filling step). Therefore, the quality of the molded product can be stabilized.

The control device 90 starts, for example, a compression operation based on the detection result of the detector 37. By adjusting the timing of starting the compression operation according to the filling state of the molding material in the mold device 30, it is possible to absorb variations in processes other than the compression process.

For example, the start of the compression operation may be performed when the control device 90 detects that the molding material M has reached a predetermined position based on the detection result of the detector 37, and the elapsed time from the time of the arrival reaches a preset compression operation start time. The variation in the timing at which the molding material M reaches the predetermined position can be absorbed, and the variation in the peak pressure can be suppressed. The compression operation start time corresponds to a set time described in claims.

The start of the compression operation may be performed when the control device 90 detects the position of the front end of the flow of the molding material M based on the detection result of the detector 37 and the detected position reaches a preset compression operation start position. The detection of the position of the flow front end of the molding material M can be performed by measuring, for example, the elapsed time from when the molding material M reaches a predetermined position. The closer the position of the front end of the flow of the molding material M is to the end point of the flow path with the passage of time.

The start of the compression operation may be performed at a time corresponding to a time required from the start of the filling step to the time when the molding material M reaches the predetermined position. For example, the longer the required time, the slower the flow of the molding material, and therefore, the compression operation can be started at a slightly slower time from the start of the filling process.

The detector 37 is disposed upstream of the inlet of the cavity space 34 in fig. 3 and 4, but may be disposed downstream of the inlet of the cavity space 34. In this case, the compression start time may be zero. The detectors 37 may be disposed on both sides of the entrance of the cavity space 34.

The control device 90 may perform the position control of the compression operation after the start of the compression operation. In this position control, the position of the member performing the compression operation can be controlled. The control device 90 controls the position of the member performing the compression operation so as to be the set position. The control may be any of feedback control and feedforward control. Examples of the member performing the compression operation include the compression member 36, the ejector rod 63, and the ejector plate 64.

The position of the member performing the compression operation is detected by a position sensor 65. The position sensor 65 is attached to a fixed member (for example, the block 51 of the intermediate device 50 in fig. 1 and 2), but may be attached to a movable member. As the position detector 65, an encoder 61a of the eject motor 61 may be used.

The control device 90 may perform position control of the compression operation based on the detection result of the detector 37 after the start of the compression operation. The setting position of the member performing the compression operation can be changed according to the filling condition of the molding material M.

For example, the set position of the member performing the compression operation may be changed according to the elapsed time from the molding material M reaching the predetermined position, which is detected based on the detection result of the detector 37, or may be changed at a speed corresponding to the elapsed time.

The setting position of the member performing the compression operation may be changed according to the position of the leading end of the flow of the molding material M detected based on the detection result of the detector 37, or may be changed at a speed corresponding to the position of the leading end of the flow.

The set position of the member performing the compression operation may be changed at a speed corresponding to a required time required from the start of the filling process to the arrival of the molding material M at the predetermined position. For example, the flow of the molding material M is slower as the required time is longer, and thus the speed of changing the set position of the member performing the compression operation can be slower.

The control device 90 may perform pressure control of the compression operation after the start of the compression operation. In this pressure control, the pressure acting on the member performing the compression operation is controlled. The pressure applied to the member performing the compression operation corresponds to the pressure applied to the molding material M in the cavity space 34. Therefore, in the pressure control of the compression operation, the pressure applied to the member performing the compression operation can be controlled by controlling the pressure applied to the molding material M in the cavity space 34. The control device 90 controls the pressure applied to the member performing the compression operation to be a set pressure. The control may be any one of feedback control and feedforward control.

The pressure acting on the member performing the compression operation is detected by the pressure sensor 66. The pressure sensor 66 is attached to a movable member (for example, the compression member 36 in fig. 1 and 2), but may be attached to a fixed member (for example, the fixed mold 32). The pressure sensor 66 can detect the pressure acting on the member performing the compression operation by detecting the strain of the component of the ejector device 60 and the strain of the component of the intermediate device 50.

The control device 90 may perform pressure control of the compression operation based on the detection result of the detector 37 after the start of the compression operation. The pressure acting on the member performing the compression operation can be changed according to the filling condition of the molding material M, and the pressure acting on the molding material can be changed.

For example, the set pressure of the member performing the compression operation may be changed according to the elapsed time from when the molding material M reaches the predetermined position, which is detected based on the detection result of the detector 37, or may be changed at a speed corresponding to the elapsed time.

The set pressure of the member performing the compression operation may be changed according to the position of the flow front end of the molding material M detected based on the detection result of the detector 37, or may be changed at a speed corresponding to the position of the flow front end.

The set pressure of the member performing the compression operation may be changed at a speed corresponding to a required time required from the start of the filling process to the arrival of the molding material M at the predetermined position. For example, the flow of the molding material M is slower as the required time is longer, and thus the speed of changing the set pressure of the member performing the compression operation can be slower.

The control device can switch between position control and pressure control during the compression operation. Switching from position control to pressure control may be performed, or switching from pressure control to position control may be performed.

For example, the control device 90 performs position control, pressure control, and position control in sequence in a step of performing a compression operation (hereinafter, referred to as a "compression step").

The control device 90 performs position control at the beginning of the compression process so that the compression member 36 is reliably advanced to the set position and the front surface of the compression member 36 can diffuse the molding material M. Further, when the compression process is started, the pressure of the molding material M in the cavity space 34 becomes unstable. By performing the position control at the beginning, the quality of the molded product is stabilized.

The controller 90 controls the pressure during the compression process so that the molding material M is sufficiently pressed against the wall surface of the cavity space 34, thereby improving transferability. Further, since the pressure of the molding material M is stable, the density of the molding material M is stable.

The controller 90 performs position control at the end of the compression process, thereby stabilizing the final size and shape of the cavity space 34 and stabilizing the size and shape of the molded article. Finally, the compression member 36 is advanced to fill the cavity space 34 with the molding material M, thereby completing the filling of the molding material M. The pressure holding step and the cooling step are performed after the filling step.

After the compression process is completed, the position control may be continued in order to prevent the size of the cavity space 34 from being changed in the pressure holding process and the cooling process. In this position control, the movement of the compressing member 36 is prohibited. The position control may be performed to the start of the mold opening process.

In the compression step of the present embodiment, the position control, the pressure control, and the position control are performed in this order, but the number and order of switching are not particularly limited. For example, the number of times of switching may be 1, or only the position control and the pressure control may be performed in sequence, or only the pressure control and the position control may be performed in sequence. The number of times of switching may be 3 or more.

The control device 90 can switch the control of the compression operation between the position control and the pressure control based on the detection result of the detector 37. The timing of switching can be changed according to the filling state of the molding material M.

The switching of the control method of the compression operation may be performed, for example, when the control device 90 detects that the molding material M reaches a predetermined position based on the detection result of the detector 37, and the elapsed time from the arrival reaches a preset switching time.

The switching of the control method of the compression operation may be performed when the control device 90 detects the position of the leading end of the molding material M based on the detection result of the detector 37 and the detected position reaches a preset switching position.

The control device 90 can control the compression operation based on the detection result of the detector 37 after reducing the forward speed of the screw 43 in the middle of the filling process. After the forward speed of the screw 43 is decreased, the molding material flows mainly by the residual pressure or the like. Therefore, it is difficult to grasp the filling of the molding material in the mold device 30 from the position of the screw 43. Therefore, the detector 37 can significantly detect the filling of the molding material in the mold device 30.

While the embodiments of the injection molding machine and the like have been described above, the present invention is not limited to the above embodiments and the like, and various modifications and improvements can be made within the spirit of the present invention described in the claims.

For example, the compression member 36 of the above embodiment is used in two aspects: (1) compression of the molding material within the mold apparatus 30; (2) The molded product may be ejected from the mold device 30 only for (1) compression and not for (2) ejection. At this time, the ejecting member and the compressing member 36 are disposed in the mold device 30, respectively.

When the ejection member and the compression member 36 are provided separately, the ejector 60 may function as a driving device for driving the ejection member and the compression member 36 separately and independently, or may function as a driving device for driving only the ejection member. In the latter case, a driving device for driving the compressing member 36 is separately provided. For example, a hydraulic cylinder as the intermediate device 50 is used as a driving device that drives the compression member 36.

The compression member 36 in the above embodiment is disposed on the movable mold 33 side, but may be disposed on the fixed mold 32 side. At this time, the intermediate device 50 may be disposed between the fixed mold 32 and the fixed platen 12. The compression members 36 may be disposed on both sides of the movable mold 33 and the fixed mold 32, respectively.

In the above embodiment, the ejector 60 is used for the compression operation of the molding material in the cavity space, but the mold clamping device 10 may be used. In the latter case, the intermediate device 50 may be omitted, and a mold device 30A shown in fig. 5 may be used instead of the mold device 30.

The mold device 30A includes a fixed mold 32A and a movable mold 33A. The fixed mold 32A is attached to the fixed platen 12, and the movable mold 33A is attached to the movable platen 13 without passing through the intermediate device 50 shown in fig. 1 and the like.

As shown in fig. 5, the movable mold 33A includes a mold main body portion 33Aa, a frame portion 33Ab, and a spring portion 33Ac. The mold body 33Aa is attached to the movable platen 13. The frame portion 33Ab surrounds the convex portion of the mold main body portion 33Aa, and is connected to the mold main body portion 33Aa via the spring portion 33Ac.

In the mold clamping device 10, the movable platen 13 is moved forward to press the frame-shaped portion 33Ab against the fixed mold 32A, thereby contracting the spring portion 33Ac. The mold body 33Aa is advanced to a predetermined position, and a cavity space 34A is formed between the mold body 33Aa and the fixed mold 32A. Next, the mold clamping device 10 can compress the molding material in the cavity space 34A by further advancing the movable platen 13.

In fig. 5, the movable mold 33A includes the mold main body portion 33Aa, the frame-shaped portion 33Ab, and the spring portion 33Ac, but the fixed mold 32A may include these components instead of the movable mold 33A. In fig. 5, a spring is used as a connecting portion for connecting the mold main body portion 33Aa and the frame-shaped portion 33Ab, but a cylinder or the like may be used. Further, a convex portion is provided on one of the movable mold 33A and the fixed mold 32A, a concave portion is provided on the other of the movable mold 33A and the fixed mold 32A, the convex portion is inserted into the concave portion, and a cavity space can be formed between a top surface of the convex portion and a bottom surface of the concave portion.

The injection device 40 of the above embodiment is of a coaxial screw type, but may be of a premolded type. In the injection device of the pre-injection type, a molding material melted in a plasticizing cylinder is supplied to an injection cylinder, and the molding material is injected from the injection cylinder into a mold device. The screw is rotatably or rotatably disposed in the plasticizing cylinder and is movable forward and backward, and the plunger is rotatably disposed in the injection cylinder.

Claims

1. An injection molding machine is provided with:

a detector that detects a flow of the molding material in the mold device; and

and a control device for controlling the timing of the compression operation for compressing the molding material in the cavity space in the mold device, based on the detection result of the detector.

2. The injection molding machine according to claim 1,

the control means starts the compression operation based on a detection result of the detector.

3. The injection molding machine according to claim 1 or 2,

the control device detects the arrival of the molding material at a predetermined position based on the detection result of the detector.

4. The injection molding machine according to any one of claims 1 to 3,

the control device detects the arrival of the flowing front end of the molding material at a predetermined position based on the detection result of the detector.

5. The injection molding machine according to claim 3 or 4,

the control device starts the compression operation when detecting that the elapsed time from the arrival has reached a set time.

6. The injection molding machine according to any one of claims 1 to 5,

the control device performs position control for controlling the position of a member that performs the compression operation, based on the detection result of the detector.

7. The injection molding machine according to any one of claims 1 to 6,

the control device performs pressure control for controlling a pressure applied to a member performing the compression operation, based on a detection result of the detector.

8. The injection molding machine according to any one of claims 1 to 7,

the control device switches between position control of the compression operation and pressure control of the compression operation according to a detection result of the detector.