DE102011102313A1 - Control device for electrical operated injection molding machine, has reference value calculating unit computing value obtained from parts of screw retreat amount and screw rotation amount as plasticizing rate reference value - Google Patents

Abstract

The device has an injection screw (3) movably arranged in an injection cylinder (1), where the screw is rotatable back and forth. An injection servomotor (M1) rotates and drives the screw, and a position detector (Penc2) detects a screw rotation amount in a preset section. A plastification rates reference value calculating unit computes a value obtained from parts of screw retreat amount detected by a screw retreat amount detecting unit, and the screw rotation amount as a plasticizing rate reference value.

Description

BACKGROUND

Technical part

The present invention relates to a controller for an injection molding machine, and more particularly to a controller for an injection molding machine having a plasticizing state monitoring means.

State of the art

A controller for an injection molding machine performs a control in a dosing step to apply back pressure to a resin and plastic material, and to plastic by rotating a screw at a predetermined rotational speed and retracting the screw to a predetermined dosing end position to melt and knead while the pressure of the molten plastic is controlled to a predetermined back pressure. Then, when the worm reaches the predetermined dosing end position, the rotation of the worm is stopped and the dosing step is ended. In this dosing step, there may be cases where the plasticization rate fluctuates, for example, due to the fluctuation of the temperature of a cylinder and the fluctuation of a friction factor between a plastic material and an inner wall of the injection cylinder. Further, in the following explanation, the "plasticization rate" means the amount of plastic that is plasticized at every screw rotation. A high plasticization rate means that a large amount of plastic can be plasticized with every screw turn.

As the plasticizing rate fluctuates, the metering time fluctuates to plasticize a predetermined amount of plastic, and therefore, there is a concern that characteristics such as the viscosity of a molten resin to be molded will fluctuate, thereby making the molded products defective. Thus, a method of monitoring a metered state of a plastic in a metering step is conventionally known.

For example, the published Japanese Patent Application No. 4-282219 a dosing time monitoring device that detects the dosing time of each state in the dosing step and decides whether or not the detected dosing time of each state is within a range between an upper limit value and a lower limit value. However, with this prior art method, the metering time fluctuates not only due to the plasticization rate but also due to a metering rotational speed or metering stroke, and therefore there is a problem that even by monitoring the metering time, the plasticization rate can not be accurately determined ,

The Published Japanese Patent Application No. 63-91220 discloses a method of calculating, in a computing device, the shift amount based on the number of screw rotations and the screw retraction speed as a kneading index in the plasticization process. However, this method calculates the shift amount from, for example, the cross-sectional area of a groove of the worm, the cross-sectional area of the worm or the diameter of the worm, and therefore has the problem that the calculation becomes complicated, for example, and a calculation formula for each worm design must be changed.

The Published Japanese Patent Application No. 3-118132 discloses a method of cumulatively calculating the screw rotation amount from a screw rotation start period, and using this screw rotation amount as a monitoring item in a charging / metering step. However, with this method, the value obtained by cumulatively calculating the screw amount fluctuates not only due to the plasticization rate but also due to a metering stroke, and therefore there is a problem that the plasticization rate can not be accurately determined even by monitoring the value obtained by cumulatively calculating the screw rotation amount ,

Summary of the invention

Therefore, in view of the above-described disadvantages of the prior art, an object of the present invention is to provide a controller for an injection molding machine which can accurately calculate a plasticization rate set value without being affected by fluctuation of a screw rotation speed or a metering stroke during the metering.

The control-controlled injection molding machine according to a first aspect of the present invention comprises an injection cylinder, a worm rotatably and reciprocally disposed in the injection cylinder, worm rotation drive means for rotating and driving the worm, worm rotation amount detection means for detection an amount of screw rotation in a predetermined portion, and screw retreat amount detecting means for detecting an amount of screw retreat in a predetermined portion. And the controller includes plasticization rate setpoint Calculating means for calculating a value obtained by dividing the screw retraction amount detected by the screw retreat amount detecting means by the value obtained by the worm rotational amount detected by the worm rotational amount detecting means as a plasticizing rate command value.

The control-controlled injection molding machine according to a second aspect of the present invention comprises an injection cylinder, a worm rotatably and reciprocally mounted in the injection cylinder, worm rotation drive means for rotating and driving the worm, worm rotation speed detection means for detection a screw rotation speed in a predetermined portion, and screw retreat speed detecting means for detecting a screw retreat speed in a predetermined portion. And the controller includes plasticization rate command value calculating means for sequentially calculating a value obtained by dividing the screw retreating speed detected by the screw retreating speed detecting means by the value obtained by the screw rotational speed detecting means, as a plastication rate command value.

The controller may further include error-free / erroneous decision means for deciding whether or not a molded product is faultless or defective based on the calculated plasticization rate setpoint. The controller may further include a table in which a standard plasticization rate value per type of plastic material is predetermined and stored, with an upper limit or lower limit taking a value for the error-free / erroneous decision used in the error-free / erroneous decision-making means which is obtained by multiplying the standard plasticization rate value read from the table by a predetermined factor.

The controller may further include temperature setting means for adjusting a temperature of the injection cylinder such that the calculated plasticization rate setpoint coincides with a predetermined target value.

The controller may further include back pressure adjusting means for adjusting a back pressure in the dosing so that the calculated plasticization rate setpoint coincides with a predetermined target value.

The controller may further include screw rotational speed setting means for adjusting a screw rotational speed such that the calculated plasticization rate setpoint coincides with a predetermined target value.

The controller may further include a table in which a standard plasticization rate value per type of plastic material is predetermined and stored, and the standard plasticization rate value read from the table may be preset as the predetermined target value.

The predetermined portion may be a portion between a dosing start and a dosing end, or may be any portion of a plurality of portions obtained by further dividing a portion between a dosing start and a dosing end.

The present invention can provide a controller for an injection molding machine in which a plasticization rate set value can be accurately calculated without being affected by fluctuation of a screw rotation speed or a metering stroke during the metering.

Brief description of the drawings

1 Fig. 12 is a block diagram of a main part of an example of a controller according to an embodiment of the present invention and an electrically operated injection molding machine driven by this controller;

2 Fig. 10 is a flowchart illustrating a processing algorithm when the value obtained by dividing the screw retraction amount during the dosing by the screw rotation amount during dosing is used as a plasticization rate set value;

3 FIG. 10 is a flowchart illustrating a processing algorithm when the value obtained by dividing the screw retraction speed during metering by the screw rotational speed during metering is used as a plasticization rate command value; FIG.

4A and 4B 10 are flowcharts illustrating algorithms having processing for setting a reference value for deciding whether a molded product is defect-free or defective based on a plasticization rate setpoint;

5A and 5B 10 are flowcharts illustrating algorithms having processing for adjusting the temperature of an injection cylinder such that a plasticization rate setpoint coincides with a predetermined target value;

6A and 6B 13 are timing diagrams illustrating algorithms having processing for adjusting the backpressure in metering so that a plasticization rate setpoint coincides with a predetermined target value; and

7A and 7B FIG. 10 are flowcharts illustrating algorithms having processing for adjusting the screw rotation speed such that a plasticization rate setpoint coincides with a predetermined target value.

Description of the Preferred Embodiments

Since a screw is retracted while a pressure of the molten plastic is controlled to coincide with a predetermined back pressure in a dosing step, a screw retraction amount is generally directly proportional to a plasticized amount of plastic. Further, as described above, since the plasticization rate refers to the amount of plastic that is plasticized at each screw rotation, the total screw rotation amount in the dosing step is inversely proportional to a plasticization rate. A high plasticization rate means that a large amount of plastic can be plasticized with every screw rotation.

Thus, with focus on these characteristics, the features of the present invention are in the calculation of a plasticization rate setpoint based on the screw retraction amount and the screw rotation amount during the metering. That is, the features of the present invention are in the calculation of a value obtained by dividing the screw retraction amount during the metering by the screw rotation amount as a plasticization rate set value.

1 FIG. 10 is a block diagram of a main part of an example of a controller according to an embodiment of the present invention and an electrically operated injection molding machine driven by this controller.

A nozzle part 2 is at the front end of an injection cylinder 1 attached to the injection molding machine, and an injection screw 3 is in the injection cylinder 1 introduced. A pressure sensor 5 For example, a pressure cell that detects the pressure on the injection screw 3 is applied to this injection screw 3 provided to the plastic pressure in the injection cylinder 1 to eat. The pressure sensor 5 can detect the back pressure during dosing. At the outer periphery of the injection cylinder 1 is a heating unit, for example, a heating tape, which is not shown attached.

The injection screw 3 is transmitted by a worm-turning servomotor M2 via a gear unit 6 , which is formed for example with a disc or a belt rotated. Furthermore, the injection screw 3 by an injection servomotor M1 via the gear unit 7 driven, having a mechanism for converting the rotational movement of a disc, a belt, a ballscrew or a nut mechanism in a linear movement, and in an axial direction of the injection screw 3 emotional.

In 1 becomes the position / velocity of the injection screw 3 in the axial direction by detecting the position / velocity of the injection servomotor M1 by means of a position / velocity detector Penc1. The rotational position and the rotational speed of the injection screw 3 are detected by detecting the position / velocity of the worm rotary servo motor M2 by means of a position / velocity detector Penc2. A hopper 4 is used to supply a plastic material to the injection cylinder 1 used.

The control 10 an injection molding machine has a CNC CPU 20 , which is a numerical control microprocessor, a PMC CPU 17 , which is a programmable machine control microprocessor, and a servo CPU 15 , which is a servo control microprocessor, and transmits information between the microprocessors by selecting an input / output of the respective processors via the bus 26 ,

The servo CPU 15 is with a ROM 13 which stores a control program suitable for servo control for performing position control loop, speed loop and current loop processing, and a RAM 14 which is used to temporarily store data. Furthermore, this servo CPU 15 with an A / D (analog / digital) converter 16 connected to a pressure signal from the pressure sensor 5 detecting various pressures, for example, an injection pressure provided on the injection molding machine main body side.

The servo CPU 15 is also equipped with a servo amplifier 11 of the injection servo motor M1 connected to an injection axis, based on the command from the servo CPU 15 drives, and with a servo amplifier 12 connected to a connected to a screw rotary axis (English: screw rotary axis) connected screw rotary servomotor M2 drives. In addition, the position / velocity detector Penc1 is attached to the injection servomotor M1 and provides an output from that position / velocity sensor. Detector Penc1 to the servo CPU 15 back. Further, the position / velocity detector Penc2 is attached to the screw-turn servo motor M2, and supplies an output from this position / velocity detector Penc2 to the servo CPU 15 back.

The rotational positions of the injection servomotor M1 and the auger rotation servomotor M2 are controlled by the servo CPU 15 calculated based on position feedback signals from the position / velocity detectors Penc1 and Penc2, and updated and stored in each current position register.

1 only the servomotors M1 and M2 that drive the injection axis and the worm rotation axis, the position / velocity detectors Penc1 and Penc2 that detect the rotational positions / velocities of the servomotors M1 and M2, and the servo amplifiers 11 and 12 , The same applies to the configuration of each axis, for example a clamping axis for clamping a casting mold and an ejector axis for removing a molded product from the casting mold, and is known in US Pat 1 omitted.

The in PMC-CPU 17 is with a ROM 18 for example, storing a sequence program for controlling a sequence operation of the injection molding machine, and a RAM 19 which is used, for example, to temporarily store calculated data, and the CNC CPU 20 is with a ROM 21 for example, which stores an automatic operation program for fully controlling the injection molding machine, and a RAM 22 For example, it is used to temporarily store calculated data. A cast data storage RAM 23 The non-volatile memory is a molding data storing memory which stores, for example, molding conditions with respect to an injection molding process, various predetermined values, parameters and macro variables. The casting data storage RAM 23 stores a plasticization rate reference value P, which will be described below, as a plasticization rate value table for each plastic material.

An LCD attached manual input device (LCD / MDI) 25 is by bus 26 via an LCD display circuit 24 and numeric keys for inputting numerical data and various function keys to select a graph display screen or a function menu, and to perform a process of inputting various data. The screen display may also indicate a decision result for a faultless product.

According to the above configuration, the PMC CPU controls 17 a sequence of operations of the entire injection molding machine, the CNC CPU 20 distributes a move command to the servomotor of each axis, for example based on the operating program of the ROM 21 and the in the cast data RAM 23 stored casting conditions, and the servo CPU 15 performs servo control such as position loop control, speed loop control, and current loop control similar to the prior art based on the motion command distributed to each axis and the feedback signals provided by the position / velocity detectors Penc1 and Penc2 detected positions and speeds, and performs so-called digital servo processing to control the driving of the injection servo motor M1 and the worm rotary servo motor M2.

The above injection molding machine and its control have functions described below for carrying out the processing in 2 to 7B to execute illustrated algorithms.

<Screw-turning amount detection unit>

For the screw rotation amount detection unit, for example, the position detector Penc2 which detects the position of the screw rotation servomotor M2 is used. An encoder (rotarg encoder) is used for this position detector Penc2. Further, it may be conceivable to detect and store values of the rotary encoder at times when the dosing step is started and ended, and to detect the difference between the two detected and stored values as the screw turning amount. Instead, it may be conceivable to provide a rotational speed detector in a worm rotation axis, and to obtain a time integration value of a worm rotational speed between times when the dosing step is started and terminated. Further, in the case where a value of a rotary encoder attached to the worm-turn servo motor M2 is detected, the worm-turning amount can be calculated taking into consideration the reduction ratio between the worm-turning drive motor and the worm in the FIG recorded value of the encoder.

<Screw retraction amount detection unit>

For the worm retraction amount detection unit, the worm position Detecting unit used, which detects the position of the screw in the forward / backward direction of movement. More specifically, the position detector Penc1 which detects the position of the injection servomotor M1 is used. A rotary encoder is used for this position detector Penc1. Further, it may be conceivable to detect and store values of a screw position at times when the dosing step is started and ended, and to detect the difference between the two detected and stored values as the screw retraction amount. Rather than the screw forward / backward movement speed detecting unit for detecting the speed of the worm in the forward / backward moving direction (for example, the speed detector Penc1 detecting the speed of the injection servomotor M1 ), it may be conceivable to determine a time integration value of the screw forward / backward movement speed between the times when the dosing step is started and ended.

<Plastifizierungsraten setpoint>

The value obtained by dividing the screw retraction amount during dosing by the screw rotation amount during dosing is calculated as a plasticization rate set point during dosing. In this case, the calculated setpoint is an average plasticization rate setpoint in the dosing step.

Further, by dividing a portion between the start of metering and the end of metering into a plurality of sections and detecting the screw retraction amount and the screw rotation amount in the respective divided sections, a value obtained by dividing the detected screw retraction amount by the screw rotation amount as a plasticization rate command value used in each section. In this case, the setpoint calculated in this way is an average plastication setpoint in the respective sections.

Instead, it may be conceivable to use a value obtained by dividing the screw-backward travel speed during dosing by a screw rotational speed during dosing as a plasticization rate set point during dosing. In this case, the setpoint calculated in this way is a plastication rate setpoint at the respective times of the dosing step.

<Defective / decision>

By displaying the calculated plasticization rate set point on the display, it is possible to provide a plasticization quality monitoring unit. Further, it is possible to decide whether or not a molded product is faultless or defective based on the calculated plasticization rate set point. For example, if the calculated plasticization rate setpoint is less than a lower limit, there is the possibility that the plasticization rate may be reduced due to some of the factors and properties of a molten plastic fluctuating compared to the normal state, so that it is possible to decide that a product is faulty. Further, if the calculated plasticization rate set point is higher than an upper limit, there is a possibility that the plasticization rate is too high due to some factors and characteristics of a molten resin fluctuating compared to the normal state, so that it is possible to to decide that a product is defective.

<Upper limit and lower limit for error-free / faulty decision>

An upper limit value and a lower limit value for the error-free / defective decision can be specified by a user. Further, a method of making a no-fault decision by conventionally comparing the amount of injection molding with the upper limit and the lower limit of error-free decision is conventionally known, and therefore the user has no particular one Difficulty setting upper limit and lower limit for error free / fault decision. However, the upper limit value and the lower limit value for the error-free / defective decision must be set individually according to the type of a plastic material, and thus there is a concern that the user will change the upper limit value each time the plastic material is changed and the lower limit value for the error-free / faulty decision.

Thus, it is conceivable to make a table specifying and storing a standard plasticization rate value per type of plastic material, and the value obtained by multiplying the standard plasticization rate value read from this table by a predetermined factor as the upper limit or lower limit to use for the error-free / faulty decision used in the error-free / faulty decision unit. For the lower limit, a positive value less than one is set for the predetermined factor, whereas for the lower limit, a value greater than one is set for the predetermined factor. Further, the predetermined factor may be set according to the required quality or level of accuracy of a molded product. For example, in the case of a molded product requiring a high quality or degree of accuracy, the range between the upper limit and the lower limit for the error free / defective decision can be set closer to (one) each for the predetermined factor for the upper limit and also for the predetermined lower limit value are reduced.

<Plastifizierungsraten control>

By controlling the temperature of the injection cylinder 1 so that the calculated plasticization rate setpoint agrees with a predetermined target value, it is possible to control the plasticization rate to stabilize it. For example, if the calculated plasticization rate setpoint is less than the predetermined target value, the amount of heating discharged from a heater to a plastic is insufficient and the plasticization rate is lowered, and hence the temperature of the injection cylinder 1 can be increased. In contrast, when the calculated plasticization rate target value is larger than the predetermined target value, the heating amount discharged from the heater to the resin becomes too high, and the plastic is not sufficiently kneaded by a screw flight, and thus the Temperature of the injection cylinder 1 can be reduced.

Further, by controlling the backpressure at the metering so that the calculated plasticization rate setpoint agrees with a predetermined target value, it is possible to control the plasticization rate so as to stabilize it. For example, if the calculated plasticization rate set point is less than the predetermined target value, the back pressure in the metering is greater than a reasonable value and the plastic is not moved to the front of the screw and thus the back pressure can be increased, whereas the calculated plasticization rate set point is higher than the predetermined target value, the back pressure in the dosing is less than a reasonable value, and adequate compression for stabilizing the plastic density is not exerted on the plastic, and thus the back pressure in the dosing can be controlled; that this is increased.

Further, by controlling the screw rotation speed so that the calculated plasticization rate set value agrees with a predetermined target value, it is possible to control the plasticization rate so as to be stabilized. For example, if the calculated plasticization rate setpoint is less than the predetermined target value, the screw rotation speed is too fast and the melting caused by transferring heat from the heater is insufficient, and thus the screw rotation speed can be reduced, whereas if the calculated set value is greater than the predetermined target value, the screw rotation is too slow and the melting is sufficiently caused by transferring heat from the heater, and thus the screw rotation speed can be controlled to be increased.

<Value obtained by dividing the screw rotation amount by the screw retraction amount>

As described above, a value obtained by dividing the screw retraction amount during dosing by the screw rotation amount during dosing is used as a plasticization rate set value during dosing. Alternatively, however, a value obtained by dividing the amount of draft rotation by the screw retraction amount may be used as a plasticization rate command value. In this case, the calculated plasticization rate setpoint is a value that is inversely proportional to the plasticization rate.

Following are the in 2 to 7 described flowcharts described.

2 FIG. 10 is a flowchart illustrating a processing algorithm in which the value obtained by dividing the screw retraction amount during dosing by the screw rotation amount during dosing is used as a plasticization rate set value according to the present invention. The respective steps will be described below. Further, a plastic is manually filled into the injection cylinder at the time when the processing is started.

[Step SA100] An injection / hold pressure step is executed.

[Step SA101] The dosing is started.

[Step SA102] A screw rotation encoder value C1 is detected and stored at the time when the dosing is started.

[Step SA103] A screw position X1 is detected and stored at the time when the dosing is started.

[Step SA104] Whether the dosing is finished or not is decided, and the algorithm proceeds to step SA105 when the dosing is finished.

[Step SA105] A screw encoder value C2 is detected at the time and stored when the dosing is finished.

[Step SA106] A screw position X2 is detected and stored at the time when the dosing is finished.

[Step SA107] The screw rotation amount (C2-C1) is determined from the encoder value C1 detected in step SA102 and the encoder value C2 detected in step SA105, and the screw retraction amount (X2-X1) is further derived from the screw position X1 detected in step SA103 In step SA106, the screw position X2 detected, and the target value ΔX / ΔC of the plasticizing rate are determined by calculating ΔX / ΔC = (X2-X1) / (C2-C1) determined.

[Step SA108] Whether or not the value of the set value ΔX / ΔC of the plasticization rate obtained in Step SA107 is within a previously set range for a good product is decided, and if the value is within the range for a good product, the algorithm proceeds with step SA107, and if the value is not within the range for a good product, the algorithm proceeds to step SA110.

[Step SA109] The decision result that the product is error free is output.

[Step SA110] The decision result that the product is defective is output.

[Step SA111] Whether or not an operation is completed is decided, and if the operation is not completed, the algorithm returns to Step SA100 and continues this process, and if the process is completed, this process is ended.

3 Fig. 10 is a flow chart illustrating a processing algorithm when the value obtained by dividing the screw retraction speed during dosing by the screw rotational speed during dosing is used as a plasticization rate set value.

[Step SB100] An injection / hold pressure step is executed.

[Step SB101] The dosing is started.

[Step SB102] A screw retraction speed Vx is detected and stored.

[Step SB103] A screw rotation speed Vc is detected and stored.

[Step SB104] The screw retraction speed Vx detected in step SB102 is divided by the worm rotational speed Vc detected in step SB103 (i.e., Vx / Vc is detected).

[Step SB105] Whether or not the value Vx / Vc determined in step SB104 is within the previously specified range for a defect-free product is decided, and if the value is within the range for a defect-free product, the algorithm proceeds to step SB106 and, if the value is not within the range for a good product, the algorithm proceeds to step SB107.

[Step SB106] The decision result that the product is error free is output.

[Step SB107] The decision result that the product is defective is output.

[Step SB108] Whether the dosing is finished or not is decided, and if the dosing is not completed, the algorithm returns to step SB102 and continues this process, and when the dosing is finished, the algorithm proceeds Step SB109 continues.

[Step SA109] Whether or not an operation is completed is decided, and if the operation is not completed, the algorithm returns to the step SB100 and continues this process, and if the operation is completed, this process is ended ,

Further, although with the above example the decision in step SB105 is made multiple times during the dosing step, it may be finally decided that the product is defective if it is decided once during the dosing step that a product is defective.

4A and 4B 10 are flowcharts illustrating algorithms having processing for setting a reference value for deciding whether a molded product is defect-free or defective based on a plasticization rate setpoint. Further, a plastic is manually filled in advance in the injection cylinder at the time when the operation is started.

[Step SC100] The type of a plastic is specified.

[Step SC101] A plasticization rate reference value P is read from the plasticization rate value table for each plastic material.

[Step SC102] The lower limit value for the error-free / defective decision is determined from the reference value P read in step SC101 according to an equation P × (1-α) (where α is an arbitrary value of 0 <α <1), and this determined lower limit is specified.

[Step SC103] The upper limit value for the error free / defective decision is obtained from the reference value P read in step SC101 according to an equation P × (1 + α), and this detected upper limit value is set.

[Step SC104] An injection / hold pressure step is executed.

[Step SC105] The dosing is started.

[Step SC106] A screw encoder value C1 is detected and stored at the time when the dosing is started in step SC105.

[Step SC107] A screw position X1 is detected and stored at the time when the dosing is started in step SC105.

[Step SC108] Whether the dosing is finished or not is decided, and the algorithm proceeds to step SC109 when the dosing is finished.

[Step SC109] A screw encoder value C2 is detected at the time and stored when the dosing is finished.

[Step SC110] A screw position X2 is detected and stored at the time when the dosing is finished.

[Step SC111] The screw rotation amount (C2-C1) is detected by the encoder value C1 detected in step SC106 and the encoder value C2 detected in step SC109, and the screw retraction amount (X2-X1) is further derived from the screw position X1 detected in step SC107 In step SC110, the detected screw position X2 is detected, and the target value ΔX / ΔC of the plasticizing rate is calculated by calculating ΔX / ΔC = (X2-X1) / (C2-C1) determined.

[Step SC112] Whether or not the plasticization rate set value ΔX / ΔC determined in step SC111 is between the lower limit value set in step SC102 and the upper limit value set in step SC102 or not within a range for a faultless product is decided and if so If the value is within the range for a good product, the algorithm proceeds to step SC113, and if the value is not within the range for a good product, the algorithm proceeds to step SC114.

[Step SC113] The decision result that the product is error free is output.

[Step SC114] The decision result that the product is defective is output.

[Step SC115] Whether or not an operation has been completed is decided, and if the operation is not completed, the algorithm returns to step SC104 and continues this process, and if the operation is completed, this process is ended ,

5A and 5B 13 are flowcharts illustrating algorithms having processing for adjusting the temperature of the injection cylinder such that a plasticization rate setpoint coincides with a predetermined target value. Further, in advance, a plastic is manually filled in the injection cylinder at the time when the operation is started.

[Step SD100] The type of a plastic is specified.

[Step SD101] A plasticization rate reference value P is read from the plasticization rate value table for each plastic material.

[Step SD102] The plasticization rate reference value P read in step SD101 is set as a target value for the plasticization rate.

[Step SD103] An injection / hold-pressure step is executed.

[Step SD104] The dosing is started.

[Step SD105] A screw encoder value C1 is detected at the time and stored when the dosing is started.

[Step SD106] A screw position X1 is detected and stored at the time when the dosing is started.

[Step SD107] Whether the dosing is finished or not is decided, and the algorithm proceeds to step SD108 when the dosing is finished.

[Step SD108] A screw encoder value C2 is detected and stored at the time when the dosing is finished.

[Step SD109] A screw position X2 is detected at the time and stored when the dosing is finished.

[Step SD110] The screw rotation amount (C2-C1) is determined from the encoder value C1 detected in step SD105 and the encoder value C2 detected in step SD108, and the screw retraction amount (X2-X1) is further derived from the screw position X1 detected in step SD106 In step SD109, detected screw position X2 is detected, and the target value ΔX / ΔC of the plasticizing rate is calculated by calculating ΔX / ΔC = (X2-X1) / (C2-C1) determined.

[Step SD111] Whether or not the target value ΔX / ΔC of the plasticization rate obtained in step SD110 is greater than the target value obtained in step SD102 is decided, and if the value is larger, the algorithm proceeds to step SD112, and if the value is smaller, the algorithm proceeds to step SD113.

[Step SD112] The temperature of the injection cylinder is lowered.

[Step SD113] The temperature of the injection cylinder is increased.

[Step SD114] Whether a process is finished or not is decided, and if the process is not completed, the algorithm returns to step SD103 and continues this process, and if the process is finished, this process is ended.

6A and 6B 13 are timing diagrams illustrating algorithms having processing for adjusting the back pressure at the metering so that a plasticization rate set point coincides with a predetermined target value.

[Step SE100] The type of a plastic is specified.

[Step SE101] A plasticization rate reference value P is read from the plasticization rate value table for each plastic material.

[Step SE102] The plasticization rate reference value P read in step SE101 is set as a target value for the plasticization rate.

[Step SE103] An injection / hold pressure step is executed.

[Step SE104] The dosing is started.

[Step SE105] A screw rotation sensor value C1 is detected at the time and stored when the dosage is started.

[Step SE106] A screw position X1 is detected and stored at the time when the dosing is started.

[Step SE107] Whether the dosing is finished or not is decided, and the algorithm proceeds to step SE108 when the dosing is finished.

[Step SE108] A screw encoder value C2 is detected at the time and stored when the dosing is finished.

[Step SE109] A screw position X2 is detected and stored at the time when the dosing is finished.

[Step SE110] The screw rotation amount (C2-C1) is determined from the encoder value C1 detected in step SE105 and the encoder value C2 detected in step SE108, and the screw retraction amount (X2-X1) is further derived from the screw position X1 detected in step SE106 and FIG In step SE109, the detected screw position X2 is detected, and the target value ΔX / ΔC of the plasticizing rate is calculated by calculating ΔX / ΔC = (X2-X1) / (C2-C1) determined.

[Step SE111] Whether or not the plasticization rate set value ΔX / ΔC determined in step SE110 is greater than a target value is decided, and if the value is larger, the algorithm proceeds to step SE112, and if the value is smaller , the algorithm proceeds to step SE113.

[Step SE112] The back pressure in the dosing is increased.

[Step SE113] The back pressure in the dosing is reduced.

[Step SE114] Whether or not an operation is completed is decided, and if the operation is not completed, the algorithm returns to step SE103 and continues this process, and if the operation is completed, this process is ended.

7 Fig. 10 is a flowchart illustrating an algorithm having processing for adjusting the screw rotation speed so that a plasticization rate set value coincides with a predetermined target value.

[Step SF100] The type of a plastic is specified.

[Step SF101] A plasticization rate reference value P is read from the plasticization rate value table for each plastic material.

[Step SF102] The plasticization rate reference value P read in step SF101 is set as a target value for the plasticization rate.

[Step SF103] An injection / hold pressure step is executed.

[Step SF104] The dosing is started.

[Step SF105] A screw encoder value C1 is detected at the time and stored when the dosing is started.

[Step SF106] A screw position X1 is detected and stored at the time when the dosing is started.

[Step SF107] Whether the dosing is finished or not is decided, and the algorithm proceeds to step SF108 when the dosing is finished.

[Step SF108] A screw encoder value C2 is detected at the time and stored when the dosing is finished.

[Step SF109] A screw position X2 is detected and stored at the time when the dosing is finished.

[Step SF110] The screw rotation amount (C2-C1) is determined from the encoder value C1 detected in step SF105 and the encoder value C2 detected in step SF108, and the screw retraction amount (X2-X1) is further derived from the screw position X1 detected in step SF106 and FIG In step SF109, detected screw position X2 is detected, and the target value ΔX / ΔC of the plasticizing rate is calculated by calculating ΔX / ΔC = (X2-X1) / (C2-C1) determined.

[Step SF111] It is decided whether the target value ΔX / ΔC of the plasticization rate obtained in Step SF110 is larger than a target value, and if the value is larger, the algorithm proceeds to Step SF112 and, if the value is smaller, moves the algorithm proceeds to step SF113.

[Step SF112] The screw rotation speed is increased.

[Step SF113] The screw rotation speed is reduced.

[Step SF114] Whether or not an operation has ended is decided, and if the operation is not completed, the algorithm returns to step SF103 and continues this process, and if the operation is completed, this process is ended.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 4-282219 [0004]
• JP 63-91220 [0005]
• JP 3-118132 [0006]

Claims (10)

An injection molding machine controller comprising an injection cylinder, an injection screw rotatably reciprocated in the injection cylinder, screw-rotation drive means for rotating and driving the screw, screw rotation amount detection means for detecting a screw rotation amount in a predetermined manner Section, and worm retraction amount detection means for detecting a worm retraction amount in a predetermined section, the control comprising: Plastication rate target value calculation means for calculating a value obtained by dividing the screw retraction amount detected by the screw retreat amount detecting means by the value obtained by the screw rotational amount detected by the screw rotational amount detecting means as a plasticization rate command value. An injection molding machine controller comprising an injection cylinder, an injection screw rotatable and reciprocally movable in the injection cylinder, screw rotation drive means for rotating and driving the screw, screw rotation speed detection means for detecting a screw rotation speed a predetermined portion, and worm retraction speed detecting means for detecting a worm retraction speed in a predetermined portion, the controller comprising: Plastication rate target value calculating means for sequentially calculating a value obtained by dividing the screw retreating speed detected by the screw retreating speed detecting means by the value of the screw rotational speed detected by the screw rotational speed detecting means as a plasticizing rate command value. The controller for an injection molding machine according to claim 1 or 2, further comprising error-free / erroneous decision means for deciding whether or not a molded product is defect-free or defective based on the calculated plasticization rate command value. The control unit for an injection molding machine according to claim 3, further comprising a table in which a standard plasticization rate value per type of plastic material is predetermined and stored, wherein an upper limit or a lower limit value is used for the faultless / faulty used in the error free / faulty decision means. Decision, takes a value obtained by multiplying the standard plasticization rate value read from the table by a predetermined factor. The controller for an injection molding machine according to claim 1 or 2, further comprising temperature adjusting means for adjusting a temperature of the injection cylinder so that the calculated plasticization rate command value coincides with a predetermined target value. The control for an injection molding machine according to claim 1 or 2, further comprising backpressure adjusting means for adjusting a back pressure at the metering so that the calculated plastication rate target value coincides with a predetermined target value. The controller for an injection molding machine according to claim 1 or 2, further comprising screw rotational speed setting means for setting a screw rotational speed so that the calculated plasticization rate target value coincides with a predetermined target value. The controller for an injection molding machine according to claim 5, further comprising a table in which a standard plasticization rate value per type of plastic material is predetermined and stored, wherein the standard plasticization rate value read from the table is set as the predetermined target value. The controller for an injection molding machine according to claim 1 or 2, wherein the predetermined portion is a portion between a dosing start and a dosing end. The controller for an injection molding machine according to claim 1 or 2, wherein the predetermined portion is any portion of a plurality of portions obtained by further dividing a portion between a dosing start and a dosing end.

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