JP2012000929A - Controller of injection molding machine having plasticization condition monitoring means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of an injection molding machine accurately calculating an index value of plasticizing capability without being affected by the rotational speed of a screw during measurement or a change in measurement stroke.SOLUTION: An injection/dwelling process is executed, measurement is started, a screw rotary encoder value C1 at the start of measurement is detected and stored, and a screw position X1 at the start of measurement is detected and stored (SA100-SA103). Whether measurement has been completed or not is determined and. When the measurement has been completed, a screw rotary encoder value C2 at the completion of measurement is detected and stored, and a screw position X2 at the completion of measurement is detected and stored (SA104-SA106). ΔX/ΔC as screw retraction amount/screw rotational amount is calculated. Whether ΔX/ΔC is in a non-defective product range is determined. When the ΔX/ΔC is within the non-defective product range, a non-defective product determination is output. On the other hand, when the ΔX/ΔC is not in the non-defective product range, a defective product determination is output. Whether to end operation is determined. When the operation does not end, process returns to the step SA100 to continue processing. When the operation ends, processing is terminated (SA107-SA111).

Description

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

  The metering process in the injection molding machine is controlled by rotating the screw at the set rotational speed and by retracting the screw to the set weighing completion position while controlling the molten resin pressure so that the set back pressure is reached. The resin is melt kneaded. When the screw reaches the set measurement completion position, the screw rotation is stopped and the measurement process is terminated. In this measuring step, the plasticizing ability may fluctuate due to fluctuations in the cylinder temperature, fluctuations in the friction coefficient between the resin material and the inner wall of the injection cylinder, and the like. In the present invention, the plasticizing ability means the amount of resin to be plasticized per one screw rotation. High plasticizing ability means that many resins can be plasticized per screw rotation.

  If the plasticizing ability varies, the measurement time for plasticizing a predetermined amount of resin will vary, so the characteristics such as the viscosity of the molten resin injected into the mold will vary, and the molded product may become defective. . Therefore, a technique for monitoring the measurement state of the resin in the measurement process is conventionally known.

For example, in Patent Document 1, a measuring time monitoring device that measures the time of each stage in the measuring process and determines whether or not the measured measuring time of each stage is within a set upper limit value and lower limit value. Is disclosed.
Patent Document 2 discloses a technique for calculating a slip amount by an arithmetic device from the number of rotations of a screw and a reverse speed and using it as an index for kneading in a plasticizing process.

  Japanese Patent Application Laid-Open No. 2003-228561 discloses a technique of accumulating the screw rotation amount from the screw rotation start timing and using this screw rotation amount as one of the monitoring items during the charge / metering process.

JP-A-4-282219 JP-A-63-91220 JP-A-3-118132

  However, in the technique disclosed in Patent Document 1, since the measuring time varies not only with the plasticizing ability but also with the measuring rotational speed and the measuring stroke, the plasticizing ability cannot be accurately determined even if the measuring time is monitored. There was a problem.

  Further, in the technique disclosed in Patent Document 2, the amount of slip is calculated from the cross-sectional area of the screw groove, the cross-sectional area of the screw, the diameter of the screw, etc. There were problems such as the need to change the calculation formula.

  Further, in the technique disclosed in Patent Document 3, the value obtained by cumulatively calculating the screw rotation amount varies depending not only on the plasticizing ability but also on the measuring stroke. There is a problem that the ability to make it impossible to determine accurately.

  Accordingly, in view of the above-described problems of the prior art, an object of the present invention is an injection molding that can accurately calculate an index value of plasticizing ability without being affected by fluctuations in screw rotation speed and measurement stroke during measurement. It is to provide a control device for the machine.

The invention according to claim 1 of the present application is directed to an injection cylinder, a screw rotatably disposed in the injection cylinder, and a screw rotation driving means for rotationally driving the screw, and a screw in a predetermined section. In a control device for an injection molding machine having a screw rotation amount detection means for detecting a rotation amount and a screw retraction amount detection means for detecting a screw retraction amount within a predetermined section, the screw retraction amount detected by the screw retraction amount detection means A control device for an injection molding machine, comprising: a plasticizing ability index value calculating means for calculating a value obtained by dividing the value by the screw rotation amount detected by the screw rotation amount detecting means as an index value of the plasticizing ability. .
According to a second aspect of the present invention, there are provided an injection cylinder, a screw rotatably and reciprocally disposed in the injection cylinder, a screw rotation driving means for rotationally driving the screw, and a screw rotation speed within a predetermined section. In a control device for an injection molding machine having a screw rotation speed detection means for detecting a screw retraction speed and a screw retraction speed detection means for detecting a screw retraction speed within a predetermined section, the screw retraction speed detected by the screw retraction speed detection means, An injection molding machine control device comprising: a plasticizing ability index value calculating means for sequentially calculating a value obtained by dividing the screw rotating speed detected by the screw rotating speed detecting means as an index value of the plasticizing ability.

The invention according to claim 3 is provided with quality determination means for determining quality of the molded product based on the calculated index value of the plasticizing ability. It is a control apparatus of the injection molding machine.
In the invention according to claim 4, the upper limit value or lower limit value of the pass / fail judgment used by the pass / fail judgment means is the plasticizing ability read from a table in which a standard plasticizing ability value is set for each type of resin material. 4. The control apparatus for an injection molding machine according to claim 3, wherein the control value is a value obtained by multiplying a reference value by a predetermined coefficient.
The invention according to claim 5 includes temperature adjusting means for adjusting the cylinder temperature so that the calculated index value of the plasticizing ability coincides with a predetermined target value. It is a control apparatus of the injection molding machine as described in one.

The invention according to claim 6 is characterized by further comprising a measured back pressure adjusting means for adjusting the measured back pressure so that the calculated index value of the plasticizing ability coincides with a predetermined target value. It is a control apparatus of the injection molding machine as described in any one of these.
The invention according to claim 7 includes screw rotation speed adjusting means for adjusting the screw rotation speed so that the calculated index value of the plasticizing ability matches a predetermined target value. It is a control apparatus of the injection molding machine as described in any one of these.
In the invention according to claim 8, the predetermined target value is a plasticizing ability reference value for setting a plasticizing ability reference value read from a table in which a standard plasticizing ability value is set for each type of resin material. It has a setting means, It is a control apparatus of the injection molding machine as described in any one of Claims 5-7 characterized by the above-mentioned.

The invention according to claim 9 is the injection molding machine according to any one of claims 1 to 8, wherein the predetermined section is a section from a measurement start to a measurement end. It is a control device.
The invention according to claim 10 is characterized in that the predetermined section is an arbitrary section obtained by further dividing a section from a measurement start to a measurement end into a plurality of sections. It is a control device for an injection molding machine characterized by being one.

  According to the present invention, it is possible to provide an injection molding machine control device capable of accurately calculating an index value of plasticizing ability without being affected by fluctuations in screw rotation speed and metering stroke during metering.

It is a principal part block diagram of one Embodiment at the time of applying this invention to an electric injection molding machine. It is a flowchart which shows the algorithm of a process at the time of setting the value which remove | divided the screw retraction amount in the measurement which concerns on this invention by the screw rotation amount in measurement as the parameter value of plasticizing ability. It is a flowchart which shows the algorithm of a process when the value which remove | divided the screw retraction speed | velocity | rate in the measurement which concerns on this invention by the screw rotational speed in measurement is made into the parameter value of plasticization ability. It is a flowchart which shows the algorithm containing the process which sets the reference value of the quality determination of a molded article based on the index value of the plasticization ability which concerns on this invention (the 1). It is a flowchart which shows the algorithm containing the process which sets the reference value of the quality determination of a molded article based on the index value of the plasticization ability which concerns on this invention (the 2). It is a flowchart which shows the algorithm containing the process which adjusts the temperature of an injection cylinder so that the index value of the plasticization ability which concerns on this invention may correspond to a predetermined target value (the 1). It is a flowchart which shows the algorithm containing the process which adjusts the temperature of an injection cylinder so that the index value of the plasticization capability which concerns on this invention may correspond to a predetermined target value (the 2). It is a flowchart which shows the algorithm containing the process which adjusts a measurement back pressure so that the index value of the plasticization ability which concerns on this invention may correspond to a predetermined target value (the 1). It is a flowchart which shows the algorithm containing the process which adjusts a measurement back pressure so that the index value of the plasticization ability which concerns on this invention may correspond to a predetermined target value (the 2). It is a flowchart which shows the algorithm containing the process which adjusts a screw rotational speed so that the index value of the plasticization ability which concerns on this invention may correspond to a predetermined target value (the 1). It is a flowchart which shows the algorithm containing the process which adjusts a screw rotational speed so that the index value of the plasticization ability which concerns on this invention may correspond to a predetermined target value (the 2).

  In general, in the measuring process, the screw is retracted while controlling the molten resin pressure so as to be a set back pressure, and therefore, the retraction amount of the screw and the plasticized resin volume have a directly proportional relationship. Further, since the plasticizing ability is the amount of resin to be plasticized per one rotation of the screw, the total amount of rotation of the screw in the measuring step and the plasticizing ability are inversely related. High plasticizing ability means that many resins can be plasticized per screw rotation.

  The present invention pays attention to these characteristics and is characterized in that an index value of plasticizing ability is calculated on the basis of a screw retraction amount and a screw rotation amount during measurement. That is, it is characterized in that a value obtained by dividing the screw retraction amount during measurement by the screw rotation amount is calculated as an index value of the plasticizing ability.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a principal block diagram of an embodiment in which the present invention is applied to an electric injection molding machine. A nozzle portion 2 is attached to the tip of the injection cylinder 1, and an injection screw 3 is inserted into the injection cylinder 1. The injection screw 3 is provided with a pressure sensor 5 such as a load cell that detects the pressure applied to the injection screw 3 in order to measure the resin pressure in the injection cylinder 1. The measured back pressure can be detected by the pressure sensor 5. A heating means such as a band heater (not shown) is mounted on the outer periphery of the injection cylinder 1.

  The injection screw 3 is rotated by a screw rotation servomotor M2 via a transmission means 6 composed of a pulley, a belt, or the like. The injection screw 3 is driven by a servo motor M1 for injection via a transmission means 7 including a mechanism for converting a rotational motion of a pulley, belt, ball screw / nut mechanism, etc. into a linear motion, and the shaft of the injection screw 3 Moved in the direction.

  Reference numeral Penc1 is a position / speed detector that detects the position and speed of the injection screw 3 in the axial direction by detecting the position and speed of the servo motor M1, and the reference numeral Penc2 is the position and speed of the servo motor M2. This is a position / speed detector that detects the rotational position (rotational angle) and rotational speed of the injection screw 3 by detecting. Reference numeral 4 denotes a hopper that supplies a resin material to the injection cylinder 1. The position / speed detectors Penc1 and Penc2 are used to detect the rotational position of the injection screw 3, the axial position of the injection screw 3, the rotational speed of the injection screw 3, and the axial movement speed of the injection screw 3, which will be described later. It is done.

  The injection molding machine control apparatus 10 includes a CNC CPU 20 that is a microprocessor for numerical control, a PMC CPU 17 that is a microprocessor for a programmable machine controller, and a servo CPU 15 that is a microprocessor for servo control. By selecting mutual input / output, information can be transmitted between the microprocessors.

  The servo CPU 15 is connected to a ROM 13 that stores a control program dedicated to servo control that executes processing of a position loop, a speed loop, and a current loop, and a RAM 14 that is used for temporary storage of data. The servo CPU 15 can detect a pressure signal from the pressure sensor 5 that detects various pressures such as an injection pressure provided on the injection molding machine main body side via an A / D (analog / digital) converter 16. It is connected to the.

Further, the servo CPU 15 is connected to servo amplifiers 11 and 12 for driving the injection and screw rotation servomotors M1 and M2 connected to the injection shaft and the screw rotation shaft based on a command from the servo CPU 15. Yes. Position / speed detectors Penc 1 and Penc 2 are attached to the servo motors M 1 and M 2, and outputs from the position / speed detectors Penc 1 and Penc 2 are fed back to the servo CPU 15.
The rotational position of each servo motor M1, M2 is calculated by the servo CPU 15 based on the position feedback signal from the position / speed detectors Penc1, Penc2, and updated and stored in each current position storage register.

  In FIG. 1, only the servo motors M1 and M2 for driving the injection shaft and the screw rotation shaft, the rotational positions of the servo motors M1 and M2, the position / speed detectors Penc1 and Penc2 for detecting the speed, and the servo amplifiers 11 and 12 are shown. ing. The configuration of each of the shafts, such as a mold clamping shaft for clamping the mold and an ejector shaft for taking out the molded product from the mold, is the same as this, and is not shown in FIG.

  A ROM 18 storing a sequence program for controlling the sequence operation of the injection molding machine and a RAM 19 used for temporary storage of calculation data are connected to the PMC CPU 17, and an automatic operation program for overall control of the injection molding machine is connected to the CNC CPU 20. Are connected to a ROM 21 that stores data and the like, and a RAM 22 that is used for temporary storage of calculation data. The molding data storage RAM 23 formed of a non-volatile memory is a molding data storage memory for storing molding conditions relating to injection molding work, various set values, parameters, macro variables, and the like. The molding data storage RAM 23 stores a plasticizing ability reference value P, which will be described later, as a plasticizing ability value table for each resin material.

  A manual input device with LCD (LCD / MDI) 25 is connected to a bus 26 via an LCD display circuit 24, and is provided with a numeric keypad for inputting numeric data and various function keys. In addition, various data input operations can be performed. The result of good product discrimination can also be displayed on the display.

  With the above configuration, the PMC CPU 17 controls the sequence operation of the entire injection molding machine, and the CNC CPU 20 instructs the servo motor of each axis to move based on the operating program of the ROM 21 and the molding conditions stored in the molding data storage RAM 23. Servo CPU 15 performs position loop control in the same manner as in the prior art based on the movement command distributed to each axis and the position and speed feedback signals detected by position and speed detectors Penc1 and Penc2. Servo control such as speed loop control and current loop control is performed, so-called digital servo processing is executed, and drive control of the servo motors M1 and M2 is performed.

  The injection molding machine and its control device have the functions described below in order to execute the processing of the flowchart showing the algorithm according to the present invention shown in FIGS.

<Screw rotation amount detection means>
As the screw rotation amount detection means, for example, a rotary encoder is provided as Penc2 on the screw rotation shaft, the values of the rotary encoder at the start and end of the weighing process are detected and stored, respectively, and the difference between the detected and stored two values is detected. May be requested. Further, the screw rotation shaft may be provided with a rotation speed detector, and the time integral value of the screw rotation speed from the start to the end of the measuring process may be obtained. When the value of the rotary encoder attached to the screw rotation drive motor is detected, the screw rotation amount may be detected in consideration of the reduction ratio from the screw rotation drive motor to the screw.

<Screw retraction amount detection means>
As the screw retraction amount detection means, for example, Penc 1 is provided with a screw position detection means for detecting the position in the forward / backward direction of the screw, and detects and stores the value of the screw position at the start and end of the weighing process, respectively. The difference between the two stored values may be obtained. Further, a screw forward / reverse speed detecting means for detecting the speed in the forward / backward direction of the screw may be provided, and a time integral value of the forward / backward speed of the screw from the start to the end of the measuring process may be obtained.

<Indicator value of plasticizing ability>
A value obtained by dividing the screw retraction amount during measurement by the screw rotation amount during measurement is calculated as an index value of the plasticizing ability during measurement. In this case, the calculated index value is an index value of an average plasticizing ability in the measuring process.
In addition, a value obtained by dividing a section from the start of measurement to completion of measurement into a plurality of sections, detecting a screw retraction amount and a screw rotation amount in each of the divided sections, and dividing the detected screw retraction amount by a screw rotation amount. May be calculated as an index value of the plasticizing ability in each section. In this case, the calculated index value is an index value of the average plasticizing ability in each section.
Further, a value obtained by dividing the screw retraction speed during measurement by the screw rotation speed during measurement may be calculated as an index value of the plasticizing ability during measurement. In this case, the calculated index value is an index value of the plasticizing ability at each time point of the measuring process.

<Pass / fail judgment>
By displaying the calculated plasticizing ability index value on the screen, it is possible to provide a means for monitoring the plasticizing quality. Further, the quality of the molded product can be determined based on the calculated index value of the plasticizing ability.

<Control of plasticizing ability>
By controlling the cylinder temperature so that the calculated index value matches a predetermined target value, the plasticizing ability can be controlled to be stable. For example, when the calculated index value is smaller than a predetermined target value, the amount of heat given from the heater to the resin is insufficient and the plasticizing ability is reduced, so that the cylinder temperature is raised, and the calculated index value is If it is larger than the target value, the amount of heat applied from the heater to the resin becomes excessive, and the resin kneading by screw flight is insufficient, so the cylinder temperature may be lowered.
Further, by controlling the measured back pressure so that the calculated index value coincides with a predetermined target value, the plasticizing ability can be controlled to be stable. For example, when the calculated index value is smaller than a predetermined target value, the measured back pressure is higher than the appropriate value and the resin is not sent to the front of the screw. When the index value is larger than the predetermined target value, the metering back pressure is lower than the appropriate value and appropriate compression is not applied to stabilize the resin density. Also good.

Further, by controlling the screw rotation speed so that the calculated index value matches a predetermined target value, the plasticizing ability can be controlled to be stable. For example, when the calculated index value is smaller than a predetermined target value, the screw rotation speed is too high, and melting due to heat transfer of the heater is insufficient. If the calculated index value is larger than the predetermined target value, the screw rotation speed is too slow and there is room for melting due to the heat transfer of the heater, so control is performed to increase the screw rotation speed. May be.
<Value obtained by dividing screw rotation amount by screw retraction amount>
In the above, the value obtained by dividing the screw retraction amount being calculated by the screw rotation amount during measurement was calculated as an index value of the plasticizing ability during measurement, but the value obtained by dividing the screw rotation amount by the screw retraction amount was It may be calculated as an index value of the conversion ability. In this case, the calculated index value is an index value that is inversely proportional to the plasticizing ability.

Next, the flowchart shown in FIGS. 2 to 7 will be described.
FIG. 2 is a flowchart showing an algorithm of processing when a value obtained by dividing a screw retraction amount during measurement by a screw rotation amount during measurement is used as an index value of plasticizing ability according to the present invention. Hereinafter, it demonstrates according to each step. At the start of operation, the injection cylinder is manually filled with resin beforehand.
[Step SA100] The injection / holding process is executed.
[Step SA101] Measurement is started.
[Step SA102] The screw rotation encoder value C1 at the start of measurement is detected and stored.
[Step SA103] The screw position X1 at the start of measurement is detected and stored.
[Step SA104] It is determined whether or not the measurement is completed. If the measurement is completed, the process proceeds to Step SA105.
[Step SA105] The screw rotation encoder value C2 at the completion of measurement is detected and stored.
[Step SA106] The screw position X2 at the completion of measurement is detected and stored.
[Step SA107] Calculate ΔX / ΔC which is the screw retraction amount / screw rotation amount. ΔX / ΔC = (X2-X1) / (C2-C1)
[Step SA108] It is determined whether or not ΔX / ΔC is within the non-defective range. If it is within the non-defective range, the process proceeds to Step SA109, and if not, the process proceeds to Step SA110.
[Step SA109] The non-defective product judgment is output.
[Step SA110] The defective product determination is output.
[Step SA111] It is determined whether or not the operation is finished. If the operation is not finished, the process returns to Step SA100 to continue the process. If the operation is finished, the process is finished.

FIG. 3 is a flowchart showing an algorithm of processing when the value obtained by dividing the screw retraction speed during measurement by the screw rotation speed during measurement is used as an index value of plasticizing ability according to the present invention.
[Step SB100] The injection / holding step is executed.
[Step SB101] Measurement starts.
[Step SB102] The screw reverse speed Vx is detected and stored.
[Step SB103] The screw rotation speed Vc is detected and stored.
[Step SB104] Screw retraction speed Vx / screw rotation speed Vc is calculated.
[Step SB105] It is determined whether or not Vx / Vc is within the non-defective range. If it is within the non-defective range, the process proceeds to Step SB106. If not, the process proceeds to Step SB107.
[Step SB106] A non-defective product judgment is output.
[Step SB107] The defective product judgment is output.
[Step SB108] It is determined whether or not the measurement is completed. If the measurement is not completed, the process returns to Step SB102 to continue the process. If the measurement is completed, the process proceeds to Step SB109.
[Step SB109] It is determined whether or not the operation is finished. If the operation is not finished, the process returns to Step SB100 and the process is continued. If the operation is finished, the process is finished.
In the above example, the determination in step SB105 is repeatedly executed during the weighing process. However, if it is determined as a defective product even once during the measurement process, it may be finally determined as a defective product. .

FIG. 4 is a flowchart showing an algorithm including a process for setting a reference value for quality determination of a molded product based on an index value of plasticizing ability according to the present invention. At the start of operation, the injection cylinder is manually filled with resin beforehand.
[Step SC100] The type of resin is set.
[Step SC101] The plasticizing ability reference value P is read from the plasticizing ability value table for each resin material.
[Step SC102] The lower limit value for pass / fail judgment is set to P * (1-α).
[Step SC103] An upper limit value for pass / fail judgment is set by P * (1 + α). Α is an arbitrary value of 0 <α <1.
[Step SC104] An injection / pressure holding process is executed.
[Step SC105] The measurement is started.
[Step SC106] The screw rotation encoder value C1 at the start of measurement is detected and stored.
[Step SC107] The screw position X1 at the start of measurement is detected and stored.
[Step SC108] It is determined whether or not the measurement is completed. If the measurement is completed, the process proceeds to Step SC109.
[Step SC109] The screw rotation encoder value C2 at the completion of measurement is detected and stored.
[Step SC110] The screw position X2 at the completion of measurement is detected and stored.
[Step SC111] Calculate ΔX / ΔC which is the screw retraction amount / screw rotation amount. ΔX / ΔC = (X2-X1) / (C2-C1)
[Step SC112] It is determined whether or not ΔX / ΔC is within the non-defective range. If it is within the non-defective range, the process proceeds to Step SC113. If not, the process proceeds to Step SC114.
[Step SC113] A non-defective product judgment is output.
[Step SC114] The defective product judgment is output.
[Step SC115] It is determined whether or not the operation is finished. If the operation is not finished, the process returns to step SC104 to continue the process. If the operation is finished, the process is finished.

FIG. 5 is a flowchart showing an algorithm including a process of adjusting the temperature of the injection cylinder so that the index value of the plasticizing ability according to the present invention matches a predetermined target value. At the start of operation, the injection cylinder is manually filled with resin beforehand.
[Step SD100] Set the type of resin.
[Step SD101] The plasticizing ability reference value P is read from the plasticizing ability value table for each resin material.
[Step SD102] The target value of the plasticizing ability is set to the read plasticizing ability reference value P.
[Step SD103] An injection / pressure holding process is executed.
[Step SD104] Measurement is started.
[Step SD105] The screw rotation encoder value C1 at the start of measurement is detected and stored.
[Step SD106] The screw position X1 at the start of measurement is detected and stored.
[Step SD107] It is determined whether or not the measurement is completed. If the measurement is completed, the process proceeds to step SD108.
[Step SD108] The screw rotation encoder value C2 at the completion of measurement is detected and stored.
[Step SD109] The screw position X2 at the completion of the measurement is detected and stored.
[Step SD110] ΔX / ΔC, which is the screw retraction amount / screw rotation amount, is calculated. ΔX / ΔC = (X2-X1) / (C2-C1)
[Step SD111] It is determined whether or not ΔX / ΔC is larger than the target value. If larger, the process proceeds to Step SD112, and if smaller, the process proceeds to Step SD113.
[Step SD112] Lower the temperature of the injection cylinder.
[Step SD113] Raise the temperature of the injection cylinder.
[Step SD114] It is determined whether or not the operation is finished. If the operation is not finished, the process returns to step SD103 to continue the process. If the operation is finished, the process is finished.

FIG. 6 is a flowchart showing an algorithm including a process of adjusting the measured back pressure so that the index value of the plasticizing ability according to the present invention matches a predetermined target value.
[Step SE100] The type of resin is set.
[Step SE101] The plasticizing ability reference value P is read from the plasticizing ability value table for each resin material.
[Step SE102] The target value of the plasticizing ability is set to the read plasticizing ability reference value P.
[Step SE103] An injection / pressure holding process is executed.
[Step SE104] Measurement is started.
[Step SE105] The screw rotation encoder value C1 at the start of measurement is detected and stored.
[Step SE106] The screw position X1 at the start of measurement is detected and stored.
[Step SE107] It is determined whether or not the measurement is completed. If the measurement is completed, the process proceeds to Step SE108.
[Step SE108] The screw rotation encoder value C2 at the completion of measurement is detected and stored.
[Step SE109] The screw position X2 at the completion of measurement is detected and stored.
[Step SE110] Calculate ΔX / ΔC which is the screw retraction amount / screw rotation amount. ΔX / ΔC = (X2-X1) / (C2-C1)
[Step SE111] It is determined whether or not ΔX / ΔC is larger than the target value. If larger, the process proceeds to Step SE112, and if smaller, the process proceeds to Step SE113.
[Step SE112] Increase the weighing back pressure.
● [Step SE113] Lower the measurement back pressure.
[Step SE114] It is determined whether or not the operation is finished. If the operation is not finished, the process returns to Step SE103 to continue the process. If the operation is finished, the process is finished.

FIG. 7 is a flowchart showing an algorithm including a process of adjusting the screw rotation speed so that the index value of the plasticizing ability according to the present invention matches a predetermined target value.
[Step SF100] The type of resin is set.
[Step SF101] The plasticizing ability reference value P is read from the plasticizing ability value table for each resin material.
[Step SF102] The target value of the plasticizing ability is set to the read plasticizing ability reference value P.
[Step SF103] An injection / pressure holding process is executed.
[Step SF104] Measurement is started.
[Step SF105] The screw rotation encoder value C1 at the start of measurement is detected and stored.
[Step SF106] The screw position X1 at the start of measurement is detected and stored.
[Step SF107] It is determined whether or not the measurement is completed. If the measurement is completed, the process proceeds to step SF108.
[Step SF108] The screw rotation encoder value C2 at the completion of measurement is detected and stored.
[Step SF109] The screw position X2 at the completion of measurement is detected and stored.
[Step SF110] Calculate ΔX / ΔC which is the screw retraction amount / screw rotation amount. ΔX / ΔC = (X2-X1) / (C2-C1)
[Step SF111] It is determined whether or not ΔX / ΔC is larger than the target value. If larger, the process proceeds to step SF112, and if smaller, the process proceeds to step SF113.
[Step SF112] Increase the screw rotation speed. [Step SF113] Decrease the screw rotation speed.
[Step SF114] It is determined whether or not the operation is finished. If the operation is not finished, the process returns to step SF103 to continue the process. If the operation is finished, the process is finished.

DESCRIPTION OF SYMBOLS 1 Injection cylinder 2 Nozzle part 3 Injection screw 4 Hopper 5 Pressure sensor 6, 7 Transmission means M1 Servo motor for injection M2 Servo motor for screw rotation Penc1, Penc2 Position / speed detector 10 Control device

Claims (10)

An injection cylinder, a screw rotatably disposed in the injection cylinder, and a reciprocating screw, a screw rotation driving means for rotationally driving the screw, and a screw rotation amount detecting means for detecting a screw rotation amount within a predetermined section And a control device for an injection molding machine having a screw retraction amount detecting means for detecting a screw retraction amount within a predetermined section.
A plasticizing ability index value calculating means for calculating a value obtained by dividing the screw retracting amount detected by the screw retracting amount detecting means by the screw rotating amount detected by the screw rotating amount detecting means as an index value of the plasticizing ability; A control device for an injection molding machine. An injection cylinder, a screw rotatably disposed in the injection cylinder, and a reciprocating screw, a screw rotation driving means for rotating the screw, and a screw rotation speed detecting means for detecting a screw rotation speed within a predetermined section And a control device for an injection molding machine having a screw retraction speed detecting means for detecting a screw retraction speed within a predetermined section,
A plasticizing ability index value calculating means for sequentially calculating a value obtained by dividing the screw retracting speed detected by the screw retracting speed detecting means by the screw rotating speed detected by the screw rotating speed detecting means as an index value of the plasticizing ability; A control apparatus for an injection molding machine.   The control apparatus for an injection molding machine according to claim 1, further comprising: a quality determination unit configured to determine quality of the molded product based on the calculated index value of plasticizing ability.   The upper limit value or lower limit value of the pass / fail judgment used by the pass / fail judgment means is obtained by multiplying a plasticizing ability reference value read from a table in which a standard plasticizing ability value is set for each type of resin material by a predetermined coefficient. 4. The control device for an injection molding machine according to claim 3, wherein   The injection molding machine according to any one of claims 1 and 2, further comprising temperature adjusting means for adjusting a cylinder temperature so that the calculated index value of the plasticizing ability coincides with a predetermined target value. Control device.   The metering back pressure adjusting means for adjusting the metering back pressure so that the calculated index value of the plasticizing ability coincides with a predetermined target value. Control device for injection molding machine.   3. The screw rotation speed adjusting means for adjusting the screw rotation speed so that the calculated index value of the plasticizing ability matches a predetermined target value. 4. Control device for injection molding machine.   The predetermined target value includes a plasticizing ability reference value setting means for setting a plasticizing ability reference value read from a table in which a standard plasticizing ability value is set for each type of resin material. The control device for an injection molding machine according to any one of claims 5 to 7.   9. The control device for an injection molding machine according to claim 1, wherein the predetermined section is a section from a measurement start to a measurement end.   The predetermined section is any one of sections obtained by further dividing a section from the start of measurement to the end of measurement into a plurality of sections. Control device for injection molding machine.

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