JP2004299135A - Method for controlling push-in force of molding material and injection molding machine for carrying out the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the occurrence of the irregular density state of a molding material in the groove of an injection screw. <P>SOLUTION: When injection pressure P detected during injection operation is larger than a set value (x) of injection pressure, the pressing force to the molding material in a hopper from above by a push-in member is reduced (ST4) and, when the injection pressure P is smaller than the set value (x) inversely, the pressing force is increased (ST5). Further, when the rotary driving force F of the injection screw detected during the metering operation after injection operation is larger than a set value (y) of rotary driving force, the pressing force to the molding material in the hopper from above by the push-in member is reduced (ST8) and, inversely, when the rotary driving force F of the injection screw detected is smaller than the set value (y), the pressing force is increased (ST9). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial applications]
According to the present invention, in an injection molding machine, a sheet-shaped or solid molding material larger than a pellet having a columnar shape is charged into a hopper, and a pressing force is applied to the molding material from above in the hopper during a molding cycle. And the adjustment of the pressing force when applying pressure.
[0002]
[Prior art]
There are various types of plastic materials for molding by an injection molding machine. These are roughly classified into thermoplastic materials such as PE and PET (polyethylene, polyethylene terephthalate), thermosetting materials such as melanin and urea resin, and It can be divided into materials close to thermosetting such as silicon rubber and BMC (Bulk Modulus Compound).
[0003]
The thermoplastic molding material is preliminarily processed into a pellet shape, and is put into a hopper of an injection molding machine as a pellet. Further, the thermosetting molding material is in a powder form. However, rubber-based molding materials such as BMC and silicone rubber are supplied to the market as molding materials in sheet form or cylindrical / cylindrical form. The present applicant has already proposed a device for efficiently feeding and switching a sheet-like or cylindrical molding material into a hopper.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 7-53956
Such a BMC or rubber-based molding material (hereinafter simply referred to as a molding material) is vulcanized at the manufacturing stage and contains a large amount of volatile components, so that it deteriorates during storage and transportation, that is, the volatile components are contained in the material. Great care has been taken not to be exposed to the open air to preserve. (For example, when injection molding is performed using the molding material having a reduced volatile component, the molded product becomes cloudy and impairs the molding quality.)
[0006]
Attention is also paid to the operating conditions during the metering process so that the molding compound is not subjected to excessive shearing or heating by the injection screw in the barrel of the injection molding machine and its effective volatile components are dissipated.
Also, unlike pellets, this molding material cannot be dropped or supplied from the hopper to the inside of the barrel through the barrel opening by its own weight, so the upper end portion of the molding material is pressed downward in the hopper, and the molding material is pressed. Pushing means for pushing into the barrel opening is required. The pressing of the molding material by the pushing means is usually performed in a measuring step, that is, while the injection screw is rotated, the plasticized molding material is sent to the barrel tip and stays there, and the injection screw is kept until the staying amount reaches a predetermined amount. Is continued during the step of retracting according to the amount of residence.
[0007]
[Problems to be solved by the invention]
However, there is a problem in that a molded article produced by the above-described injection molding machine still has plasticization non-uniformity in terms of molding quality, and the molding material becomes uneven in the molded article.
[0008]
The present inventor has made intensive efforts and studies to solve the above problems, and as a result, in the injection step following the measurement step, paying attention to not applying the indenting force to this molding material different from the pellet, It has been found that the above problem can be solved by applying a pushing force.
[0009]
Accordingly, an object of the present invention is to provide a method for controlling a pressing force capable of obtaining a molded product with as little plasticization non-uniformity and compactness as possible in molding with a BMC or rubber-based molding material. An object of the present invention is to provide an injection molding machine using the method.
[0010]
[Means for Solving the Problems]
The pushing force control method according to the present invention for achieving the above object,
A barrel in which an injection nozzle is mounted at the tip and an injection screw is rotatably and removably inserted therein, a hopper disposed at a molding material supply port position at the rear of the barrel, and the molding material supplied in advance in the hopper are used. First driving means for pushing the inside of the barrel through the hopper bottom opening, second driving means for moving the injection screw forward during the injection step, third driving means for rotating the injection screw during the measuring step, and the first drive A method for controlling the driving of the first driving means in an injection device including a pressing force detecting means for measuring a pressing force generated by driving the means,
A first step of driving the first drive means during the weighing step to supply the molding material in the hopper into the barrel;
A second step of driving the first drive means during the injection step to supply the molding material in the hopper into the barrel.
[0011]
In that case, the second step drives the first drive unit during the injection process by associating a physical quantity reflecting the injection operation state during the injection process with the pressing force detected by the pressing force detection unit. It may be configured to include a step of generating a drive command signal for controlling.
[0012]
In this case, during the injection step, an injection pressure based on the driving of the second drive unit is detected, and the detected value is compared with a preset injection pressure set value. When the detection value is smaller than a set value, the driving force of the first driving unit is adjusted so as to increase the pressing force when the detected value is smaller than the set value. it can.
[0013]
In this case, a rotational driving force for the injection screw based on the driving of the third driving means is detected during the measuring step, and the detected value is compared with a preset value of the rotational driving force, and the detection is performed. When the value is larger than the set value, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is increased so as to increase the pushing force. Can be adjusted.
[0014]
Furthermore, in that case, the injection pressure based on the driving of the second driving means is detected during the injection step, and the detected value is compared with a preset injection pressure set value, and the detected value is set to the set value. When the detected value is smaller than the set value, the driving force of the first driving unit is adjusted so as to increase the pressing force when the detected value is smaller than the set value. ,
During the weighing step, a rotational driving force for the injection screw based on the driving of the third driving unit is detected, and the detected value is compared with a preset value of the rotational driving force, and the detected value is set to the set value. When the value is larger, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is adjusted so as to increase the pushing force. Can be.
[0015]
Further, to achieve the above object, an injection molding machine for applying a pressing force to a molding material in a hopper according to the present invention,
A barrel having an injection nozzle attached to the tip thereof and having an injection screw rotatably and removably inserted therein, a hopper disposed at a molding material supply port position at the rear of the barrel, and the molding material previously supplied into the hopper are used. First driving means for pushing the inside of the barrel through the hopper bottom opening, second driving means for moving the injection screw forward during the injection step, third driving means for rotating the injection screw during the measuring step, and the first drive An injection device having a pressing force detecting means for measuring a pressing force generated by driving the means, generating a drive command signal for each driving means of the injection device, and receiving a detection signal relating to driving from each driving means. An injection molding machine having a controller for storing in a data memory.
The controller stores, as means for generating the drive command signal, a command control program in a pushing step, an injection step, and a weighing step corresponding to the first drive unit, the second drive unit, and the third drive unit of the injection device, respectively. A command control program in the pushing step is executed while the injection step is in progress, and the first driving means controls the pushing force in response to a drive command signal from the controller during the injection operation. Configured to generate.
[0016]
In that case, the controller detects the injection pressure based on the driving of the second driving means during the injection step, compares the detected value with a preset injection pressure set value, and determines that the detected value is When the detected value is smaller than the set value, the driving force of the first driving unit is adjusted so as to increase the pressing force when the detected value is smaller than the set value. And a push-in process control program that generates a command control signal.
[0017]
In this case, the controller detects the rotational driving force of the injection screw based on the driving of the third driving means during the measuring process, and compares the detected value with a preset value of the rotational driving force. When the detected value is larger than the set value, the driving force of the first driving means is adjusted so as to reduce the pushing force, and when the detected value is smaller than the set value, the first driving means is made to increase the pushing force. It can be provided with a pushing process control program for generating a command control signal to adjust the driving force of the means.
[0018]
Furthermore, in that case, the controller detects an injection pressure based on the driving of the second driving means during the injection step, compares the detected value with a preset injection pressure set value, and performs the detection. When the value is larger than the set value, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is increased so as to increase the pushing force. And adjust
During the weighing step, a rotational driving force for the injection screw based on the driving of the third driving unit is detected, and the detected value is compared with a preset value of the rotational driving force, and the detected value is set to the set value. When the detected value is smaller than the set value, the driving force of the first driving unit is adjusted so as to increase the pressing force when the detected value is smaller than the set value. And a push-in process control program for generating a command control signal.
[0019]
[Action]
During the measuring step, the first driving means is driven to supply the molding material in the hopper into the barrel, and during the injection step, the first driving means is driven to supply the molding material in the hopper into the barrel. In this case, a drive command signal for driving and controlling the first drive unit during the injection process is generated by associating a physical quantity reflecting the injection operation state during the injection process with the pressing force detected by the pressing force detection unit. .
By driving the first driving means also during the injection process, the density of the molding material supplied to the injection screw groove in the barrel is eliminated.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example of an embodiment according to the present invention will be described in detail with reference to FIGS.
[0021]
FIG. 1 is a front view of an injection device in an injection molding machine for injection-molding a molded product made of a molding material such as BMC or rubber. FIG. 2 is an enlarged vertical sectional view of the injection screw showing a portion where the molding material is supplied into the injection screw, and FIG. 3 is a view taken along line ZZ of FIG. Show the shape.
[0022]
In FIG. 1, a support base 10 is mounted on a base BS arranged on the injection device side of the injection molding machine. The support base 10 is provided with a barrel support portion 12 for penetrating a barrel 14 through which the injection screw 16 is rotatably and removably inserted and fixed by fastening means 12A. Further, a band heater 18 is provided on the outer peripheral portion on the left side of the barrel 14 so as to heat the inside of the barrel 14.
[0023]
Reference numeral 20 denotes an injection nozzle, which is attached to the left end of a nozzle support 24 attached to the left end of the barrel 14. Reference numeral 16A denotes a shaft portion of the injection screw 16, and 16B (see FIG. 2) denotes a seal ring mounted near the tip of the injection screw 16, which prevents the molten resin from flowing backward during measurement.
[0024]
A hopper 26 for supplying molding material to the groove of the injection screw 16 via the barrel 14 is disposed above the barrel 14 of the barrel support 12. Further, a guide 22 is provided at the upper end of the barrel support 12. On this guide 22, a hydraulic cylinder 32 provided with a pressure sensor 32A at the upper end and a pushing force applied downwardly from the upper opening of the hopper 26 to the molding material in the hopper 26 attached to the lower end of the rod of the cylinder 32. A pushing device PSD having a pushing member 30 for generating is provided.
[0025]
That is, as shown in the drawing, the pushing device PSD further includes a frame body 25 erected on the guide 22 so as to be slidable in a direction perpendicular to the plane of the drawing, a cylinder mounting plate 28 fixed to the top thereof, and a not shown. Has a drive unit for moving the frame body 25 along the guide 22.
[0026]
The drive unit moves the pushing member 30 and the frame body 25 during the operation of newly supplying molding material from the upper opening of the hopper 26 or the operation of cleaning, mounting, disassembling, etc. of the hopper 26 itself, and This secures a space above the opening.
[0027]
A guide 34 is disposed on the right upper surface of the support base 10, and a rotation transmitting device 42 that applies a rotational force to the shaft 16 </ b> A of the injection screw 26 via the engaging portion 36 is mounted on the guide 34. . The engaging portion 36 is configured such that the axial movement of the injection screw 16 is restricted by a nut 42B and can transmit only rotation.
[0028]
Above the rotation transmitting device 42, a servomotor 38 for measurement is disposed via a support 40. Accordingly, the rotation of the servomotor 38 is transmitted to the lower rotation transmission device 42 via the pulley and the timing belt inside the cover 42A, and further applied to the shaft portion 16A of the injection screw 16 via the engagement portion 36.
[0029]
The rotation transmitting device 42 is disposed on the guide 34 so as to be slidable in the X direction. Although not shown, an injection injection cylinder for moving the rotation transmission device 42 and the injection screw 16 in the X direction is disposed in parallel with the injection screw 16 on the barrel support portion 12, and a piston rod end of each cylinder is provided. The part is fixed to the rotation transmitting device 42.
[0030]
In FIG. 2, the band heater 18 is attached to the outer peripheral surface on the left side of the barrel 14 as described above. The bottom 26A of the hopper 26 is open in the barrel 14, and the molding material is supplied to the groove of the injection screw 16 in the barrel 14 through the opening.
[0031]
Reference numeral 36A denotes a rotational force transmitting member constituting the engaging portion 36, which is spline-coupled to the coaxial portion 16A at the right end of the shaft portion 16A of the injection screw 16.
[0032]
FIG. 3 is a view taken along the line ZZ in FIG. 2 as described above, and the bottom 26A of the hopper 26 is hermetically inserted into the supply port of the barrel 14 formed in an elliptical shape. Therefore, when the molding material inside the hopper 26 is pressed from above by the pushing member 30, it is pressed into the groove of the injection screw 16 through the opening 26B.
[0033]
FIG. 4 is a block diagram showing a configuration of drive control in various drive mechanisms of an injection molding machine to which the present invention is applied. In FIG. 4, reference numeral 50 denotes a mold opening / closing and mold clamping drive mechanism disposed on the mold clamping device side, and a sensor unit 50S detects various physical quantities related to driving of the mold opening / closing and mold clamping drive mechanism 50. It is a general term for a group of detectors. The line 50SG is a general term for transmission lines of various detection signals supplied from the sensor unit 50S to the controller 60 of the injection molding machine via the interface unit 58. The line 50D is a general term for transmission lines of various drive command signals supplied from the controller 60 to the drive mechanism 50 via the interface unit 58.
[0034]
Similarly, reference numeral 52 denotes an injection driving mechanism, and the above-described injection cylinder functions as a driving unit thereof. The sensor unit 52S includes a position detector that detects the position and / or speed of the injection screw 16, a pressure sensor that detects the back pressure of the injection cylinder, and the like. Note that the speed may be a detector that directly detects the speed, but the controller 60 may also generate a speed signal by differentiating the position signal. Further, instead of the injection cylinder, an injection driving force may be generated by using a servomotor or a linear motor as in an electric injection molding machine. In this case, the signal from the sensor section 54S passing through the line 52SG corresponds to the armature current value of the motor and a load value corresponding to the back pressure detected by a load cell separately provided on the injection screw shaft.
[0035]
Similarly, in the weighing drive mechanism 54, a driving force in the weighing mechanism is generated by the weighing servomotor 38 (see FIG. 1), and the weighing operation is performed under a predetermined back pressure condition. An armature current value flowing through the servomotor 38 from the sensor unit 54S is detected by a current detector, and given via a line 54SG. At this time, a command current value to the servo motor 38 is given to the line 54D.
[0036]
Further, reference numeral 56 is a drive mechanism of a push-in device (PSD). In the drive mechanism 56, the cylinder 32 is provided as described above for generating a pushing force, and a position detector such as the lowering or lowering limit of the pushing member 30 by the cylinder 32 and an upper portion of the cylinder 32 are provided. The provided pressure detector 32A and the like constitute the sensor section 56S. The drive mechanism 56 includes the movement and position control of the frame body 25 as described with reference to FIG. 1 in addition to the above, but the description is omitted. A signal from the sensor unit 56S is provided to the controller 60 via a line 56SG. Further, a drive command is given to each drive unit of the drive mechanism 56 via the line 56D. Note that, instead of the cylinder 30, an electric servomotor or a hydraulic motor and a mechanism for converting rotation to linear movement may be used.
[0037]
Reference numeral 70 is a hydraulic unit. The unit 70 is provided with an electromagnetic valve, a direction switching valve, an electromagnetic flow control valve, a pressure detector, and the like for supplying and discharging pressure oil to and from the hydraulic cylinders of the drive mechanisms 50, 52, and 56. A command signal to each of these valves is provided via a line 70D, and a signal from each detector is provided to the controller 60 via a line 70SG.
[0038]
The controller 60 basically includes a central processing unit CPU, a data memory DM, a program memory PM, and the interface unit 58, and is connected to each other via a bus line BS. The data memory DM stores in advance setting values of parameters such as a position, a speed, and a stroke amount for appropriately driving the driving mechanisms, and injection speed pattern data. In a memory area 62 of the program memory PM, an injection process control program including a series of command groups for driving and controlling the injection process is stored. Similarly, the memory areas 64, 66, and 68 store a weighing process control program, a pushing process control program, and a mold clamping process control program, respectively.
[0039]
Reference numeral 69 stores a sequence between processes relating to the start and end of execution of each control program, and a program for performing control, monitoring, and the like of the entire system.
[0040]
In the present invention, as shown in FIG. 5, the pushing operation during the measuring step, which was conventionally performed independently, is also performed during the injection step, and the pushing force during the pushing operation, that is, the hopper inside the hopper, Is controlled in relation to the injection pressure and the injection screw rotation driving force, respectively. Details of the pushing force control will be described below with reference to a flowchart shown in FIG.
[0041]
In FIG. 5, it is assumed that the injection molding machine is in the “ON” state in the molding cycle operation in step ST1. In step ST2, the type of operation of the injection molding machine, that is, the type of process (injection process, measuring process, mold opening and closing, mold clamping process, and the like) is sequentially determined. If it is determined in step ST2 that the ongoing process is an injection operation, the process proceeds to step ST3. If the detected injection pressure P is larger than the set value x in step ST3, the process proceeds to step ST4. The supply of the pressure oil to the cylinder 32 is instructed so as to reduce the pressing force in the step (a). On the other hand, if the injection pressure P is smaller than the set value x in step ST3, supply of pressure oil to the cylinder 32 is instructed in step ST5 to increase the pressure in the hopper 26.
[0042]
If the determination in step ST2 is "NO", the process proceeds to step ST6, where it is determined whether the ongoing process is a weighing operation. If it is determined that the weighing operation is performed, the process proceeds to step ST7. If it is determined in step ST7 that the screw driving force F during the weighing rotation is larger than the set value y, the pressure is reduced in step ST8. The supply of the pressure oil to the cylinder 32 is instructed to perform the operation. On the other hand, if it is determined in step ST7 that the screw driving force F is smaller than the set value y, in step ST9, supply of pressure oil to the cylinder 32 is instructed to increase the pressing force.
[0043]
In step ST6, if "NO" is determined, a command is issued in step ST10 to stop the supply of the pressure oil to the cylinder 32. As a result, the pressing force is eliminated, and the pushing of the molding material from the hopper 26 into the barrel 14 is interrupted.
[0044]
The pressure may be increased or decreased when the difference between the magnitudes in steps ST3 and ST7 exceeds the allowable range. In FIG. 5, the injection pressure P and the variable set value x correspond to physical quantities reflecting the injection operation state in the injection process of the present invention. The set value x, which is the target value of the injection pressure, is preset in the data memory DM as pressure pattern data at the time of injection, and usually changes according to the injection stroke position or zone.
[0045]
In the description of FIG. 1 described above, the pushing device PSD is configured to move the frame body 25 in the horizontal direction. However, by increasing the height of the frame body 25, the moving mechanism is unnecessary. . Furthermore, if an opening for opening and closing a molding material is provided in the upper side wall of the hopper 26, the molding material does not need to be supplied from the upper opening of the hopper 26, so that the stroke of the cylinder 32 is reduced accordingly.
[0046]
As shown in FIG. 2, the bottom 26A of the hopper 26 is formed in a cone shape, but the opening area of the lower end thereof is smaller than the inner diameter of the injection screw 16 because the diameter of the injection screw 16 is smaller than the inner diameter of the cylinder of the hopper 26. And the molding material is constricted as a result. The shape of the bottom of the hopper is not necessarily limited to a cone in order to more effectively apply a pushing force to the molding material.
Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and many design changes can be made without departing from the spirit of the present invention.
[0047]
【The invention's effect】
According to the present invention, during the execution of the injection process, the pressing force is applied to the molding material in the hopper so as to supply the molding material into the barrel. Can be avoided.
[0048]
Furthermore, the magnitude of the injection pressure detected during the injection operation and the set value are compared, and if there is a difference, the pressure applied to the molding material in the hopper is increased or decreased, and the amount of molding material supplied to the barrel is reduced. Since the adjustment is made in relation to the injection pressure, it is possible to avoid the above-mentioned state of coarse and dense with higher accuracy.
[0049]
Further, during the measurement process, the detected rotational driving force of the injection screw is compared with the set value, and when there is a difference, the pressure applied to the molding material in the hopper is increased or decreased, and the pressure is transferred into the barrel. The amount of molding material supplied is adjusted in relation to the rotational driving force of the injection screw, so that the dense state can be avoided with higher precision during measurement than before.
[Brief description of the drawings]
FIG. 1 is a front view of an injection device of an injection molding machine to which the present invention is applied.
FIG. 2 is an enlarged vertical sectional view of the injection screw including a portion in which a molding material is supplied from a hopper bottom into the injection screw in FIG. 1;
FIG. 3 is a view taken along line ZZ in FIG. 2, showing the shape of a molding material supply port.
FIG. 4 is a block diagram showing a configuration of drive control in various drive mechanisms of an injection molding machine to which the present invention is applied.
FIG. 5 is a flowchart illustrating a main part of a pressing process control program according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Support stand 12 Barrel support part 14 Barrel 16 Injection screw 18 Band heater 20 Injection nozzle 22 Guide 24 Nozzle support 25 Frame body 26 Hopper 28 Cylinder mounting plate 30 Push-in member 32 Cylinder 34 Guide 36 Engagement part 38 Servo motor 40 Support 42 Rotation transmission device 50 Mold opening / closing and mold clamping mechanism 52 Injection driving mechanism 54 Metering driving mechanism 56 Pushing device driving mechanism 58 Interface unit 60 Controller 62 Injection process control program 64 Metering process control program 66 Pushing process control program 68 Mold clamping process control program 70 Hydraulic unit

Claims (12)

A barrel in which an injection nozzle is mounted at the tip and an injection screw is rotatably and removably inserted therein, a hopper disposed at a molding material supply port position at the rear of the barrel, and the molding material supplied in advance in the hopper are used. First driving means for pushing the inside of the barrel through the hopper bottom opening, second driving means for moving the injection screw forward during the injection step, third driving means for rotating the injection screw during the measuring step, and the first drive A method for controlling the driving of the first driving means in an injection device including a pressing force detecting means for measuring a pressing force generated by driving the means,
A first step of driving the first drive means during the weighing step to supply the molding material in the hopper into the barrel;
Driving the first drive means in the injection step to supply the molding material in the hopper into the barrel by driving the first drive means during the injection step. 2. The first driving unit during the injection step according to claim 1, wherein the second step associates a physical quantity reflecting an injection operation state during the injection step with a pressing force detected by the pressing force detection unit. A method for controlling the driving of the first driving means in the injection device, including the step of generating a driving command signal for controlling the driving of the first driving means. 3. The injection pressure according to claim 2, wherein an injection pressure based on the driving of the second driving means is detected during the injection step, and the detected value is compared with a preset injection pressure set value. When the value is larger, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is adjusted so as to increase the pushing force. A method for controlling the driving of the first driving means in the injection device. 3. The method according to claim 2, wherein during the measuring step, a rotational driving force to the injection screw based on the driving of the third driving unit is detected, and a magnitude of the detected value is compared with a preset value of the rotational driving force. When the detected value is larger than the set value, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is increased so as to increase the pushing force. A method for controlling the driving of the first driving means in an injection device, comprising adjusting a force. 3. The injection pressure according to claim 2, wherein the injection pressure based on the driving of the second driving means is detected during the injection step, and the detected value is compared with a predetermined value of the injection pressure. When the detected value is smaller than the set value, the driving force of the first driving unit is adjusted so as to increase the pressing force when the detected value is smaller than the set value. ,
During the weighing step, a rotational driving force for the injection screw based on the driving of the third driving unit is detected, and the detected value is compared with a preset value of the rotational driving force, and the detected value is set to the set value. When the value is larger, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is adjusted so as to increase the pushing force. A method for controlling the driving of the first driving means in the injection device. The heating control method according to claim 5, wherein the temperature control means further performs PID control of the heating means in a proportional band in the PID control determined from the target temperature. A barrel having an injection nozzle attached to the tip thereof and having an injection screw rotatably and removably inserted therein, a hopper disposed at a molding material supply port position at the rear of the barrel, and the molding material previously supplied into the hopper are used. First driving means for pushing the inside of the barrel through the hopper bottom opening, second driving means for moving the injection screw forward during the injection step, third driving means for rotating the injection screw during the measuring step, and the first drive An injection device having a pressing force detecting means for measuring a pressing force generated by driving the means, generating a drive command signal for each driving means of the injection device, and receiving a detection signal relating to driving from each driving means. An injection molding machine having a controller for storing in a data memory.
The controller stores, as means for generating the drive command signal, a command control program in a pushing step, an injection step, and a weighing step corresponding to the first drive unit, the second drive unit, and the third drive unit of the injection device, respectively. A command control program in the pushing step is executed while the injection step is in progress; and the first driving means controls the pushing force in response to a drive command signal from the controller during the injection operation. An injection molding machine for applying a pushing force to a molding material in a hopper during an injection operation. 8. The controller according to claim 7, wherein the controller detects an injection pressure based on driving of the second driving means during the injection step, compares the detected value with a preset injection pressure set value, and performs the detection. When the value is larger than the set value, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is increased so as to increase the pushing force. An injection molding machine for providing a pressing force to a molding material in a hopper during an injection operation, comprising a pressing process control program for generating a command control signal to adjust the pressure. 8. The controller according to claim 7, wherein the controller detects a rotational driving force for the injection screw based on the driving of the third driving unit during the measuring step, and determines a magnitude of the detected value and a preset value of the rotational driving force. In comparison, when the detected value is larger than the set value, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the first pushing means is made to increase the pushing force. An injection molding machine for applying a pushing force to a molding material in a hopper during a weighing operation, comprising a pushing process control program for generating a command control signal to adjust a driving force of a driving means. 8. The controller according to claim 7, wherein the controller detects an injection pressure based on the driving of the second driving unit during the injection step, compares the detected value with a preset injection pressure set value, and performs the detection. When the value is larger than the set value, the driving force of the first driving means is adjusted so as to decrease the pushing force, and when the detected value is smaller than the set value, the driving force of the first driving means is increased so as to increase the pushing force. And adjust
During the weighing step, a rotational driving force for the injection screw based on the driving of the third driving unit is detected, and the detected value is compared with a preset value of the rotational driving force, and the detected value is set to the set value. When the detected value is smaller than the set value, the driving force of the first driving unit is adjusted so as to increase the pressing force when the detected value is smaller than the set value. An injection molding machine for applying a pressing force to a molding material in a hopper during an injection and metering operation, the program comprising: a pressing process control program for generating a command control signal. 11. The hydraulic pump according to claim 7, wherein the first driving unit is fixedly attached to a lower end of the piston rod, and a hydraulic cylinder disposed above the hopper and having a piston rod that advances and retreats toward an upper opening of the hopper. Injection molding for providing a pushing force to the molding material in the hopper, comprising: a pushing member for pressing the molding material in the hopper downward, and a pressure sensor for detecting the pressure in the upper oil chamber of the cylinder. Machine. 11. The electric motor according to claim 7, wherein the first driving means includes an electric servomotor disposed above the hopper and a pair of nuts and a screw shaft for converting rotation of the electric servomotor into linear movement. An injection molding machine for applying a pressing force to the molding material in the hopper, comprising a pushing member attached to one end and pressing the molding material in the hopper downward.

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