KR20180016056A - Injection molding machine for variation reduction - Google Patents

Abstract

The present invention relates to an injection molding machine which is capable of reducing quality variations of a molded article. The purpose of the present invention is to provide the injection molding machine which is manufactured from the above viewpoint, and is able to reduce quality problems of the molded article. The injection molding machine of the present invention includes: a cylinder which heats a molding material that is filled into an inner side of a mold device; a transfer member which feeds the molding material into the cylinder; a drive device which is installed at the front side of the injection molding machine and operates a reverse directional transfer member; and a controller which performs a filling process of driving a drive device for controlling speed of the transfer member, and a packing process of guiding the drive device to control pressure of the transfer member applied to the molding material, wherein the controller performs a conversion operation from the filling process carried out within the mold device with respect to a predetermined position to the packing process carried out based on the determination result of a detector for detecting arrival of the molding material.

Description

[0001] Injection molding machine for variation reduction [

The present invention relates to a high quality injection molding machine.

The casting machine has a molding material for controlling the injection device and the like, and an injection device for filling the inside of the mold device with a controller. The injection device has, for example, a cylinder, a nozzle, a screw and an injection motor. The cylinder heats the molded member. The nozzle is provided at the front end of the cylinder and pressed against the mold apparatus. The screw is made to move forward and backward in the cylinder, and supplies the molding member from the cylinder to the screw. The injection motor drives the forward and reverse screw. The controller controls the filling operation to drive the injection motor to control the speed of the screw and the pressure to act on the molding material from the screw (see Japanese Unexamined Patent Application Publication No. 2011-183704, for example) At the timing of the transition between the filling and the pressurization process, the strain in the amount of charge during all injections was large and the strain in the quality of the mold was large.

      Thereby preventing deterioration of the quality of the formed body.

       The injection molding machine of the present invention comprises a cylinder for heating a molding material to be filled therein. A conveying member for conveying the molding member in the cylinder; A drive device for operating the forward and reverse transport members;

And performs a filling operation for driving a drive device for controlling the speed of the conveying member and a holding process for leading the drvie device to control the pressure acting on the molding material from the conveying member. The controller performs a switchover to a pressure holding process based on a result of the detection by the detector that detects the arrival of the molded member from the filling operation in the mold apparatus for the predetermined position.

      Improve the quality of the formed body

2 is an exemplary diagram illustrating screw speeds in a charging process according to an embodiment of the present invention.

Although the embodiments for carrying out the invention are described below in the respective figures with reference to the drawings, the same or corresponding components are designated by the same or corresponding reference numerals, and a description thereof will be omitted.

1 is an exemplary diagram illustrating an injection molding machine according to an embodiment of the present invention. In Fig. 1, the arrow F indicates the flow of the molding material. The injection molding machine illustrated in Fig. 1 has a frame Fr, a mold clamping unit 10, an injection device 40, a controller 70 and the like. The controller 70 has a central processing unit (CPU) 71 and a storage medium 72 such as a memory. The controller 70 executes the stored program in the storage medium 72, thereby making the tightening unit 10 and the injection unit 40 a CPU 71 for controlling the mold.

Next, the mold clamping unit 10 will be described. In the description of the mold clamping unit 10, the description is based on the assumption that during the mold opening which is the front of the movable mold 13 and the direction of motion (leftward direction in Fig. 1) Will make.

The mold clamping unit 10 performs mold closing, mold clamping and mold opening of the mold apparatus 30. The mold clamping unit 10 has a fixed press plate 12, a movable platen 13, a rear platen 15, a tie-bar 16, a toggle mechanism 20, a mold clamping motor 21 and a motion conversion mechanism 25.

The fixed press plate 12 is fixed to the frame Fr. The fixed mold 32 is attached to the surface of the fixed press plate 12 facing the movable plate 13. [

The movable plate 13 is made movable along a guide (for example, a guide rail) 17 mounted on the frame Fr and made movable in the forward and reverse directions with respect to the fixed plate 12. The movable mold 33 is attached to the surface of the movable platen 13 facing the fixed platen 12. Molding, mold clamping and mold opening proceed by operating the forward and reverse movable platen 13 against the fixed press platen 12. [ The mold apparatus 30 comprises a stationary mold 32 and a movable mold 33. The rear platen 15 is coupled to the fixed press plate 12 at a distance therefrom and is positioned in the frame Fr so as to be movable in the mold start / end direction. In addition, the rear platen 15 can be moved together with the guide laid down on the frame Fr. The guide of the rear platen 15 may be shared by the guide 17 of the movable platen 13. [

Further, in the embodiment of the present invention, the fixed press plate 12 is fixed to the frame Fr and the rear platen 15 can move in the mold start / end direction with respect to the frame Fr. However, the rear platen 15 can be fixed to the frame Fr and the fixed press plate 12 can be made movable in the mold start / end direction with respect to the frame Fr.

The tie bars 16 align the space between the tie bars 16 with the fixed press plate 12 and the back platen 15. A plurality of tie bars 16 may be used. Each tie-bar 16 is made parallel to the mold start / end direction and expands in response to the clamping force. At least one tie-bar 16 has a clamping force detector 18. The clamping force detector 18 may be strain gauge type and can detect the strain of the tie-bar 16, thereby detecting the clamping force.

In addition, the clamping force detector 18 is not limited to a strain gage type, but may be a piezoelectric, capacitive, hydraulic, electronic, or the like, and its attachment position is also not limited to a tie-bar 16.

The toggle mechanism 20 is disposed between the movable platen 13 and the rear platen 15. The toggle mechanism 20 comprises a cross-head 20a, a plurality of links 20b and 20c, and so on. One link 20b is shakenly attached to the movable platen 13, and the other link 20c is attached to the rear platen 15

So that it can be heard. The links 20b and 20c are coupled so that they can flex and stretch together by pins or the like. By advancing and reversing the cross-head 20a, many of the links 20b and 20c are bent and stretched, and the movable bar 13 is moved forward and backward with respect to the rear platen 15. [

The mold clamping motor 21 is attached to the rear platen 15, and the movable platen 13 is operated forward and backward by operating the forward and reverse crossheads 20a. A motion conversion mechanism 25 is provided between the mold clamping motor 21 and the cross-head 20a for converting the rotational motion of the mold clamping motor 21 into a linear motion for transmitting the converted linear motion to the cross-head 20a. The motion conversion mechanism 25 is constituted by, for example, a ball screw unit.

The operation of the mold clamping unit 10 is controlled by the controller 70. The controller 70 controls the mold closing process, the mold clamping process, the mold opening process and the like.

In the mold closing process, the movable mold 33 is introduced into the contact with the fixed mold 32 by drawing the mold clamping motor 21 to advance the coin 13.

In the mold clamping process, the clamping force is further generated by driving the mold clamping motor 21. Cavity space 34 is formed between movable mold 33 and fixed mold 32 during mold clamping, and cavity space 34 is filled with liquid molding material. The molding material in the cavity space 34 is hardened and becomes a molded body.

In the mold opening process, the movable mold 33 is separated from the fixed mold 32 by driving the mold clamping motor 21 to operate the movable mold 13 backward.

Next, the injection device 40 will be described. Unlike the description of the mold clamping unit 10, in the description of the injection apparatus 40, the description is based on the backward direction of the screw 43 during the forward movement of the duringplasticizing screw 43 and during the filling (the rightward direction in FIG. 1) Left direction).

The injection device 40 is installed in a movable sliding base Sb and is forward and reverse with respect to the frame Fr and is movable forward and backward with respect to the mold device 30. The injection device 40 is brought into contact with the mold apparatus 30, and the inside of the mold apparatus 30 is filled with the molded member. The injection device 40 has, for example, a cylinder 41, a nozzle 42, a screw 43, a plasticizer motor 45, an injection motor 46 and a pressure detector 47.

The cylinder 41 heats the molding material supplied from the supply port 41a. The supply port 41a is formed in the rear portion of the cylinder 41. [ An aheating source such as a heater is provided on the outer circumference of the cylinder 41.

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

The screw 43 is a feeding member for feeding the molding material into the cylinder 41. The screw 43 is disposed in the cylinder 41 so as to be rotatable and movable.

The plasticizing motor 45 rotates the screw 43, thereby feeding the molding material forward along the spiral groove of the screw 43. The molding material gradually fuses by heat from the cylinder 41 while being fed. When the liquid molding material is fed forward of the screw 43 and accumulates on the front face of the cylinder 41, the screw 43 is operated backward.

The injection motor 46 is a drive device for operating the forward and reverse screw 43. The injection motor 46 actuates the forward and reverse screw 43, thereby filling the cavity space 34 of the mold apparatus 30 with the liquid molding material that has accumulated in front of the screw 43. Thereafter, the injection motor 46 pushes the screw 43 forward in the cavity space 34

, And pressure is applied to the molding material. Insufficient molding material can be refilled. A motion conversion mechanism for converting 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, for example, between the injection motor 46 and the screw 43, and the screw 43 detects the pressure it receives from the molding material and presses against the screw 43, or the like. The screw 43 receives a considerable pressure from the molding material and acts on the molding material from the screw 43 to press it.

The operation of the injection device 40 is controlled by the controller 70. The controller 70 controls the filling process, the holding process, the plasticizing process or the like.

In the filling operation, the injection motor 46 leads the screw 43 to advance the setting speed and the inside of the mold apparatus 30 is filled with the liquid molding material accumulated in front of the screw 43. The position or speed of the screw 43 is detected, for example, by the encoder 46a of the injection motor 46. The holding process is carried out subsequently to the filling operation.

In the holding process, the injection motor 46 leads the setting screw to push the screw 43 forward, and the pressure is applied to the molding material in the mold apparatus 30. Insufficient molding material can be refilled. The pressure of the molding material is detected, for example, by the pressure detector 47. The cooling process is operated after the holding process. In the cooling process, the molding material in the cavity space 34 is cured. The plasticizing process can be performed during the cooling process.

During the plasticizing process, the plasticizing motor 45 drives the screw 43 to rotate and feeds the molding material forward along the set number of turns and along the spiral groove of the screw 43. The molding material gradually fuses with this supply. When the liquid molding material is fed forward of the screw 43 and accumulates on the front face of the cylinder 41, the screw 43 is operated backward. The rotation of the numerous screws 43 is detected, for example, by the encoder 45a of the plasticizer motor 45.

In the plasticizing process, the injection motor 46 drives the screw 43 to apply a setback pressure to limit the sudden rearward movement of the screw 43. The back pressure for the screw 43 is detected, for example, by the pressure detector 47. The plasticizing process is completed when the screw 43 retracts to a predetermined position and a predetermined amount of the molding material accumulates in front of the screw 43.

2 is an exemplary diagram illustrating screw speeds in a filling operation according to an embodiment of the present invention. In Figure 2, the horizontal axis represents time and the vertical axis represents screw speed.

The setting speed of the screw 43 is set to V0 (003e # 0) and the filling operation is operated at the time. The speed of the positive screw 43 indicates the forward movement of the screw 43, and the speed of the negative screw 43 indicates the backward movement of the screw 43.

At that time, the screw 43 is operated forward at the setting speed V0, and the inside of the mold apparatus 30 is filled with the molding material accumulated in front of the screw 43.

At time t1 in the center of the filling operation, when the position of the screw 43 reaches the speed change position, the setting speed of the screw 43 falls from V0 to V1 (V0 003e # V1 003e # 0). The screw 43 is operated at a very low speed, and the molding material is made to flow mainly when residual pressure or the like. The maximum pressure of the molding material in the filling operation can be reduced, the occurrence of the flash can be reduced, and the clamping force can also be reduced. By the reduction of the clamping force, the gas leakage in the mold apparatus 30 is also excellent, and the deficient transmission can be reduced.

Moreover, V1 may be zero or negative, although it is V1 but made by the positive in FIG. The absolute value of V1 is smaller than the absolute value of V0 and the screw 43 is stopped or operated back at a very low speed. Even in such a case, the maximum pressure of the molding material in the filling operation can be reduced.

On the other hand, a time t1 (hereinafter referred to as " speed change time t1 ") at which the setting speed of the screw 43 falls from V0 to V1 after the molding material is made to flow mainly due to residual pressure or the like. The flow front of the molding material moves after the speed change time t1 regardless of the position of the screw 43. [

The controller 70 performs switching (so-called switching of V / P) from the filling operation to the hold pressure process based on the detection result of the detector 37 behind the speed change time t1.

The detector 37 detects the arrival of the molding material in the mold apparatus 30 at a predetermined position. As the detector 37, for example, a temperature sensor or a pressure sensor is used. As the detector 37, both the temperature sensor and the pressure detector are used.

Since the molded member has a temperature higher than that of the mold apparatus 30 when the molding member is at a mounting position or near the mold at the measurement value of the temperature sensor and the rising amount of the temperature sensor. The arrival of the forming member with respect to the predetermined position can be detected from the rising amount of the measurement value of the temperature sensor. For example, when the measurement value of the temperature sensor exceeds the set value, it is assumed that the molded member reaches the mounting position of the temperature sensor or its vicinity. Otherwise, it is assumed that when the time difference value of the measurement value of the temperature sensor exceeds the set value, the molded member reaches the mounting position of the temperature sensor or the vicinity thereof.

Since the pressure of the molding material acts on the pressure detector when the molded member reaches the mounting position of the pressure sensor, the pressure sensor rise amount measurement value. The arrival of the forming member with respect to the predetermined position can be detected from the increasing amount of the measurement value of the pressure sensor. For example, when the measured value of the pressure sensor exceeds the set value, it is assumed that the molded member reaches the mounting position of the pressure sensor. Otherwise, it is assumed that when the time difference value of the measurement value of the pressure sensor exceeds the set value, the molded member reaches the mounting position of the pressure sensor.

1, the detector 37 is disposed at the end of the flow path for the molding material (in particular, the cavity space 34) or in the vicinity thereof. In this case, the controller 70 switches V / P times at the time t2 at which the arrival of the molding material is detected by the detector 37 at that time.

In addition, even if the detector 37 is disposed at the end point of the flow path for the molding material in FIG. 1 or in the vicinity thereof, the detector can be arranged in the middle of the flow path for the molded member. In this case, the controller 70 anticipates the flow forward position of the molding material using the detector 37, and performs the V / P conversion for the prediction result. For example, the controller 70 detects the detector 37, thereby adjusting the elapsed time after arrival of the molded member at a predetermined position that anticipates the flow forward position of the molding material. Because the elapsed time is passing, the flow front of the molding material approaches the end point. When the elapsed time reaches the set time and the front of the flow of the molding material reaches the end point or the vicinity thereof, the switching is performed V / P times. Set time is obtained by testing or otherwise.

In addition, the detector 37 is disposed at the end of the flow path for the molding material shown in FIG. 1 or in the vicinity thereof and in the middle of the flow path for the molding material. In this case, the controller 70 can switch V / P times based on the detection results of both sides of the detector.

As described above, the controller 70 switches V / P times based on the detection result of the detector 37, according to the current selection. The deformation in the amount of filling during all the injections of the V / P number of times of switching after the detection of the arrival of the forming member against the predetermined position is surely detected after the switching of V / P times can be reduced, The deformation in the quality of the product can be reduced.

As in the present embodiment, when the setting speed of the screw 43 is made to flow primarily due to the residual pressure or the like, the filling operation and the drop in the center of the molding material, and the flow front position of the molding material can not be expected from the position of the screw 43. Therefore, the effect that the detector 37 detects the arrival of the molded member at a predetermined position is remarkably obtained.

Further, in Fig. 2, the setting speed of the screw 43 is constant from time and can be converted to a start of the filling operation and the setting speed for the speed change time t1. When the setting speed of the screw 43 is changed, the final switching time may be two or more times in the filling operation, and the speed switching time t1 may be.

In addition, even if the setting speed of the screw 43 falls in the middle of the peeling operation in Fig. 2, the setting speed may not decrease, for example, and the setting speed of the screw 43 may be constant from the start and the filling operation Of. Even in this case, the deformation in the amount of filling during all injections of the time of V / P times of switching, after the arrival of the forming member to the predetermined position is reliably detected by the detector 37 by performing the V / And the deformation in the quality of the molded body can be reduced.

Although an embodiment of an injection molding machine is described above, the present invention is not limited to the embodiments described above, and various modifications and improvements can be made within the scope of the invention described in the claims.

For example, although the injection device 40 of the above embodiment is an in-line screw type, the injection device may be of the pre-plasticizing type. The preliminary plasticizing type injection device supplies molten molding material into a plasticizing cylinder to an injection cylinder, and injects a molding member from the injection cylinder into the molding device. The screw is placed in a plasticizing cylinder to be rotatable, rotatable and movable and placed in the injection cylinder so that the forward and reverse directions, and the plunger can move, are forward and reverse. In this case, the plunger corresponds to the set of forwarding members in the claims, and the injection cylinder corresponds to the cylinder set forward in the claims.

Although the mold clamping unit 10 of the above embodiment has the mold clamping motor 21 as the drive source, the mold clamping unit can have a hydraulic cylinder instead of the mold clamping motor 21. [ Additionally, the mold clamping unit 10 may have a linear motor for mold opening and closing, and may have electromagnets for mold clamping.

enclosure

Claims (1)

the amolding material is filled into the interior of the mold apparatus 30 heated by the cylinder 41;
A conveying member 43 for conveying the molding material into the cylinder 41;
A drive device 46 for operating the forward and reverse transporting members 43; And
A controller for performing a filling operation for driving the drive device 46 for controlling the speed of the conveying member 43 and a holding process for driving the drvie device to control the pressure acting on the molding material from the conveying member 43 70), and the controller 70 here performs the switching from the detection result of the detector 37 detecting the arrival of the molding material to the holding process in the mold apparatus 30 at the predetermined position.
Here, the controller 70 performs the switching to the holding process based on the detection result of the detector 37 that detects the arrival of the molding material from the filling operation in the mold apparatus 30 at a predetermined position.

Images