JP5180891B2 - Control device for injection molding machine - Google Patents

Description

  The present invention relates to a control device for an injection molding machine suitable for use in temperature control of a heating cylinder (resin) heated by a heater.

  In general, in an injection molding machine, a heater is attached to each of a front part (metering zone), an intermediate part (compression zone), and a rear part (feed zone) of a heating cylinder provided in an injection apparatus, and heating is performed. And a control device that controls energization of each heater so that the detected temperature becomes a preset target temperature. Further, at the time of heating, since it is important to make the plasticization of the resin in the heating cylinder uniform in order to ensure the homogenization of the molded product, the management of the plasticization state is also performed.

  Conventionally, as a method for managing such plasticization, a method for managing plasticization in an injection molding machine disclosed in Patent Document 1 is known. In this management method, the reference screw rotation force required for normal weighing operation is obtained by performing a pre-calculation or execution of a test weighing operation, and the screw rotation that should be regarded as normal measurement is performed. The upper and lower permissible ranges of force are determined according to the screw position based on the reference screw rotational force, set and stored in the allowable value storage file in the non-volatile memory, and the rotational force acting on the screw during the weighing operation Are detected successively, and if the rotational force is not between the upper limit allowable range value and the lower limit allowable range value corresponding to the current position of the screw, it is assumed that plasticization abnormality has occurred, and an abnormality occurrence alarm is output. Insufficient heating of the injection cylinder, mixing of foreign matter into the molding material, insufficient supply of resin, and the like are detected.

JP-A-7-32430

  However, the conventional plasticizing management method in the above-described injection molding machine has the following problems.

  First, because it is a technique that basically determines the rotational force acting on the screw and assumes that plasticity is abnormal when the rotational force is abnormal, accurate (accurate) management is not necessarily required for the plasticized state. It cannot be done. For example, if the rotational force is affected by the inclusion of foreign matter, this effect is not directly related to the plasticized state in the first place. Especially in the case where chips of various sizes and different shapes are mixed, such as recycled materials, or when the temperature of the material itself is different, the plasticization state may not be accurately reflected by such rotational force management. Not a few.

  Secondly, because it manages the rotational force acting on the screw, it is limited to detecting abnormalities in the rotational force, and there are limits to applying effective countermeasures using the detection results. Lack. In other words, even if an abnormality is detected, stop the injection molding machine and review the weighing conditions (extending the molding cycle time, etc.) as a countermeasure, or prevent screw breakage and overheat the screw rotation motor. Although it can cope with prevention, the detection result cannot be used directly as a countermeasure against abnormality.

  An object of the present invention is to provide a control device for an injection molding machine that solves the problems existing in the background art.

  In order to solve the above-described problems, the present invention heats the heaters 3f, 3m, and 3r attached to the metering zone of the front portion 2f, the compression zone of the intermediate portion 2m, and the feed zone of the rear portion 2r in the heating cylinder 2. A heating cylinder heating means Fh for heating the cylinder 2 and a temperature control means Fc for controlling the energization of the heaters 3f so that the detected temperatures THd obtained by detecting the temperature of each zone become the preset target temperatures THs. A control device 1 for an injection molding machine M provided with control command values Ccf and Ccm for heaters 3f and 3m attached to the front portion 2f and / or the intermediate portion 2m exceeding preset threshold values Csf and Csm, and On condition that the rotational torque value Xd of the screw 4 exceeds a preset threshold value Xs when the control command values Ccf, Ccm exceed the threshold values Csf, Csm, An abnormality determination unit including an abnormality determination unit Fj for determining that the plasticization of the fat is abnormal, and an alarm display unit Fa that displays at least an alarm indicating that a plasticization abnormality has occurred if the abnormality determination unit Fj determines that the abnormality is plasticization. Fp is provided.

  In this case, according to a preferred aspect of the invention, the abnormality determining means Fj determines that the plasticization abnormality is detected on condition that the control command values Ccf and Ccm exceed the threshold values Csf and Csm for N consecutive times or exceed the set time. can do. On the other hand, when the control command values Ccf and Ccm exceed the threshold values Csf and Csm, the alarm display means Fa is used when the rotational torque value Xd of the screw 4 exceeds a preset threshold value Xs or does not exceed the threshold value Xs. Different alarm displays can be made. On the other hand, the abnormality processing means Fp can include setting changing means Fr that changes the target temperature THs for the rear portion 2r to a higher temperature automatically or manually. At this time, it is desirable that the abnormality determination unit Fj does not perform the determination until a predetermined interval time Ti elapses after the target temperature is changed by the setting change unit Fr. Further, it is desirable to apply the temperature during the measurement process to the detected temperature THd.

  According to the control device 1 of the injection molding machine M according to the present invention having such a configuration, the following remarkable effects can be obtained.

  (1) An abnormality determining means for determining that the plasticization abnormality of the resin occurs if the control command values Ccf and Ccm for the heaters 3f and 3m attached to the front part 2f and / or the intermediate part 2m of the heating cylinder 2 exceed the threshold values Csf and Csm. Since Fj is provided, disturbance factors unrelated to the plasticized state can be eliminated, and it can be accurately grasped that the plasticization abnormality, particularly plasticization is insufficient, by the heating temperature directly related to the plasticized state. Therefore, it is most suitable for a recycled material in which chips of various sizes and different shapes are mixed.

  (2) Since an abnormality processing means Fp including an alarm display means Fa for displaying an alarm indicating that a plasticizing abnormality has occurred is provided, the operator can quickly confirm that a plasticizing abnormality has occurred and quickly take necessary measures. Can be done.

  (3) In the abnormality determination means Fj, when the control command values Ccf and Ccm exceed the threshold values Csf and Csm, the plasticizing abnormality is determined on the condition that the rotational torque value Xd of the screw 4 exceeds the preset threshold value Xs. Since the determination is made, more reliable and various determinations can be performed by the composite determination based on the two factors.

  (4) According to a preferred embodiment, the abnormality determining means Fj determines that a plasticization abnormality is detected on condition that the control command values Ccf and Ccm exceed the threshold values Csf and Csm for N consecutive times or exceed the set time. By doing so, it is possible to eliminate the influence of a sudden disturbance such as a cold outside air or the like that temporarily enters and the heating temperature is lowered, and a more reliable and stable determination can be made.

  (5) When the control command values Ccf and Ccm exceed the threshold values Csf and Csm in the alarm display means Fa, the rotational torque value Xd of the screw 4 exceeds the preset threshold value Xs or If different alarm displays are performed when Xs is not exceeded, more appropriate alarm display can be performed by selecting from a plurality of different alarm displays for different results relating to plasticization abnormality.

  (6) According to a preferred embodiment, if the abnormality processing means Fp includes setting change means Fr for automatically or manually changing the target temperature THs for the rear part 2r to a higher temperature, the front part 2f and / or the middle of the heating cylinder 2 Automating plasticization before arriving at 2m, effectively eliminating plasticization abnormalities that cause insufficient plasticization, and using the determination results by the abnormality determination means Fj directly for countermeasures against abnormalities. Can also be done easily.

  (7) If the determination by the abnormality determination unit Fj is not performed until the predetermined interval time Ti has elapsed after the target temperature is changed by the setting change unit Fr according to a preferred embodiment, the unstable state after the change It is possible to prevent erroneous detection in the area.

  (8) According to a preferred embodiment, if the temperature during the weighing process is applied as the detected temperature THd ..., the weighing process that is most affected by the plasticizing abnormality can be optimized, so that the quality of the molded product is improved. Contributes to (homogenization).

The functional block diagram of the principal part in the control apparatus of the injection molding machine which concerns on suitable embodiment of this invention, Partial cross-sectional configuration diagram including an outline of a control system of an injection molding machine equipped with the control device, A flow chart for explaining the operation of the control device; Change characteristics of resin temperature, screw position and injection pressure with respect to time when using the same control device, Change characteristics diagram of resin temperature, screw position and injection pressure with respect to time of comparative example related to background art, Explanatory drawing of the comparative example,

  Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.

  First, the structure of the injection molding machine M provided with the control apparatus 1 which concerns on this embodiment is demonstrated with reference to FIG.

  In FIG. 2, M indicates an injection molding machine, in particular, an injection device Mi provided in the injection molding machine M. The injection device Mi includes a heating cylinder 2 in which a screw 11 is built, and has an injection nozzle 12 at the tip of the heating cylinder 2 and a hopper 13 attached to the rear part. An injection cylinder (hydraulic cylinder) 15 is disposed at the rear end of the heating cylinder 2, and the front end of the rod portion 16 r of the one-rod type piston 16 built in the injection cylinder 15 is coupled to the rear end of the screw 11. To do. Further, an oil motor 17 for screw rotation is disposed at the rear end of the injection cylinder 15, and a drive shaft 18 of the oil motor 17 is splined to the rear end of the piston 16. The injection cylinder 15 and the oil motor 17 are connected to a hydraulic drive circuit 19 including an electromagnetic valve and a hydraulic pump. By driving the hydraulic drive circuit 19, the screw 14 is moved forward and backward by the injection cylinder 15 and rotated by the oil motor 17.

  On the other hand, a heater 3n using a ceramic band heater or the like is attached to the outer peripheral portion of the injection nozzle 12, and three heaters 3f, 3m and 3r using a ceramic band heater or the like are attached to the outer peripheral portion of the heating cylinder 2. Attached sequentially from the front side (injection nozzle side) to the rear side along the axial direction. In this case, the heater 3f is attached to the metering zone of the front portion 2f of the heating cylinder 2, the heater 3m is attached to the compression zone of the intermediate portion 2m, and the heater 3r is attached to the feed zone of the rear portion 2r. In a large injection molding machine, the feed zone of the rear part 2r may be further divided into two front and rear zones, and two heaters may be attached to the rear part 2r. Thereby, the heating cylinder 2 is basically provided with three independent parts to be heated. Further, the injection nozzle 12 is provided with a temperature detector (thermocouple) 21n for detecting the heating temperature, and the front part 2f, the intermediate part 2m, and the rear part 2r of the heating cylinder 2 have temperature detection for detecting the heating temperature. (Thermocouple) 21f, 21m, 21r are attached respectively.

  Further, the heaters 3n, 3f, 3m, 3r and the temperature detectors 21n, 21f, 21m, 21r are connected to the temperature control unit 22, and the temperature control unit 22 is connected to the molding machine controller 23. Thus, a heating cylinder heating means Fh for energizing each heater 3f, 3m, 3r to heat the heating cylinder 2 is configured, and each zone (front part 2f, intermediate part 2m, rear part 2r) in the heating cylinder 2 is configured. The temperature control means Fc for controlling energization of the heaters 3n, 3f,... Is configured so that the detected temperatures THd obtained by detecting the temperatures become preset target temperatures THs. In this case, since the target temperature THs corresponding to each zone (front part 2f, intermediate part 2m, rear part 2r) is given to the temperature control part 22 from the molding machine controller 23, the temperature control part 22 has, for example, a front part. The deviation between the detected temperature THd detected from the 2f temperature detector 21f and the target temperature THs corresponding to the detected temperature THd is calculated by the deviation calculation unit, and this deviation is given to the PID compensation unit. Since the switching unit that controls power supply (energization) to the heater 3f by connecting to the heater 3f is built in, the switching frequency, switching time, or duty ratio of the switching unit is controlled by the switching control signal output from the PID compensation unit. Thereby, feedback control is performed so that the detected temperature THd becomes the target temperature THs. These controls are performed independently for each zone.

  On the other hand, the molding machine controller 23 is provided with a setting unit 24 for performing various settings and a display unit 25 for performing various displays. Further, the oil motor 17 in the injection device Mi is provided with a pressure detector 26 for detecting the hydraulic pressure at the time of rotation and a rotary encoder 27 for detecting the number of rotations of the oil motor 17. The pressure detector 26 and the rotary encoder 27 are connected to the molding machine controller 23, and the hydraulic drive circuit 19 is also connected to the molding machine controller 23. The molding machine controller 23 has a computer function including a CPU that executes various control processes and arithmetic processes, a memory that can store various data, and the like. The molding machine controller 23 controls the whole of the injection molding machine M, and will be described later. The control program for performing operation | movement of the control apparatus 1 which concerns on embodiment is stored.

  Next, the structure of the principal part of the control apparatus 1 which concerns on this embodiment is demonstrated with reference to FIG.1 and FIG.2.

  FIG. 1 shows a specific functional block diagram of the abnormality determination means Fj and abnormality processing means Fp constituting the main part of this embodiment. In the figure, Ccf is a control command value for the heater 3 f of the front portion 2 f, and this control command value Ccf is taken into the molding machine controller 23 from the temperature control unit 22. Ccm is a control command value for the heater 3m of the intermediate portion 2m, and this control command value Ccm is also taken into the molding machine controller 23 from the temperature control unit 22. Csf and Csm are threshold values preset by the setting unit 24. The threshold value Csf is set corresponding to the control command value Ccf, and the threshold value Csm is set corresponding to the control command value Ccm. A determination processing unit 31 on the front part 2f side compares the threshold Csf with the control command value Ccf, and outputs a determination result for the control command value Ccf based on the threshold Csf. Reference numeral 32 denotes a determination processing unit on the intermediate part 2m side, which compares the threshold Csm with the control command value Ccm and outputs a determination result for the control command value Ccm based on the threshold Csm. Xd is the rotational torque value of the screw 4 and is obtained from the detection result of the pressure detector 26. Xs is a threshold value Xs preset by the setting unit 24, and is set corresponding to the rotational torque value Xd. A determination processing unit 33 compares the threshold value Xs with the rotational torque value Xd, and outputs a determination result for the rotational torque value Xd based on the threshold value Xs. Reference numeral 34 denotes a determination processing unit that determines the outputs (determination results) of the determination processing units 31, 32, and 33 and outputs the determination results. If the above configuration is such that the control command values Ccf and Ccm for the heaters 3f and 3m attached to the front portion 2f and / or the intermediate portion 2m of the heating cylinder 2 exceed preset threshold values Csf and Csm, the resin plasticization abnormality The main part of the abnormality determination means Fj to determine is comprised.

  On the other hand, reference numeral 35 denotes an abnormality processing unit that corresponds to the output (determination result) of the determination processing unit 34 and provides display data to the display unit 25 and also applies correction data to the correction unit 36. The display unit 25 uses a display attached to the molding machine controller 23 to perform display processing corresponding to the display data. The correction unit 36 performs setting change processing using the correction data. That is, a function for setting the target temperature THs for the rear portion 2r higher by using the correction data is provided. The interval processing unit 37 has a function of preventing the determination by the abnormality determination unit Fj until a predetermined interval time Ti elapses after the setting is changed. The above configuration constitutes the setting change means Fr for changing the target temperature THs for the rear portion 2r to a higher temperature if it is determined that the abnormality is determined by the abnormality determination means Fj, and an alarm that the plasticization abnormality has occurred. The main part of the alarm display means Fa that performs display is configured, and the main part of the abnormality processing means Fp is configured. Note that the function of each unit will be described in more detail in the operation of the control device 1 described later.

  Next, the principle and operation (function) of the control device 1 according to the present embodiment will be described with reference to FIGS.

  First, the principle of the control device 1 according to the present embodiment will be described with reference to FIGS. FIG. 4 shows the resin temperature TH, the screw position Ls, and the screw pressure Pn for one molding cycle in a state where plasticization is normally performed, and a change characteristic diagram in which 100 shots are overlaid. On the other hand, FIG. 5 shows the resin temperature THp, the screw position Lsp, and the screw pressure Pnp for one molding cycle in a state where plasticization is insufficient, and shows a change characteristic diagram in which 100 shots are overlaid. The resin temperatures TH and THp are obtained by directly measuring the actual resin temperature using a molten resin temperature measuring device (see Japanese Patent No. 3146454).

  As shown in FIG. 4, when plasticization is performed normally, the variation width ΔTH of the resin temperature TH is about 1.4 ° C., and the overall variation is small. On the other hand, as shown in FIG. 5, when the plasticization is insufficient, the variation width ΔTHp of the resin temperature THp is about 18.6 [° C.], and the overall variation becomes ten times as large as the target temperature. In spite of the same, the resin temperature THp decreases as a whole, and when compared with the resin temperature TH of FIG. The target temperature is 190 [° C.]. The injection molding machine M at the time of actual operation detects the temperature of the heating cylinder 2 as shown in FIG. 2, so that a difference occurs between the target temperature and the actual resin temperature TH. Further, the injection molding machine M at the time of actual operation cannot confirm the behavior of the resin temperatures TH and THp as shown in FIGS.

  On the other hand, FIG. 6 shows the principle of variation in the resin temperature THp shown in FIG. 5 while expanding in the vertical axis direction so that the resin temperature THp in FIG. 5 can be easily understood. In FIG. 6, ts indicates the start time of the shot, and te indicates the end time of the shot. Now, when an arbitrary shot starts from the resin temperature Ta, the resin temperature changes according to the state of plasticization, and the resin temperature at the end of this shot is Tb. Then, at the start of the next shot, the resin temperature starts from this resin temperature Tb, and the resin temperature changes according to the plasticizing state, and the resin temperature at the end of this shot becomes Tc. Thereafter, similarly, at the start of the next shot, the resin temperature starts from the immediately preceding resin temperature Tc, and the resin temperature changes according to the state of plasticization, and the resin temperature at the end of this shot becomes Td. At the start of this shot, the resin temperature starts from the immediately preceding resin temperature Td, and the resin temperature changes according to the plasticizing state, and the resin temperature at the end of this shot becomes Te.

  The control device 1 according to the present embodiment pays attention to such behavior of the actual resin temperature TH, that is, the heating temperature of the front portion 2f and / or the intermediate portion 2m, and the resin generated when plasticization becomes insufficient. The control command values Ccf and Ccm are monitored in accordance with the magnitude of the variation in the temperature TH and the decrease in the resin temperature TH, that is, the control command values Ccf and Ccm when the load becomes largely unstable. This state (plasticization abnormality) is determined using threshold values Csf and Csm.

  Next, a specific operation (function) of the control device 1 according to the present embodiment will be described according to the flowchart shown in FIG. 3 with reference to FIG. 1 and FIG.

  Assume that a weighing process is being performed (step S1). In the measuring step, the screw 11 is rotated by the oil motor 17. Thereby, the solid molding material supplied to the feed zone (rear part 2r) is sent to the front compression zone (intermediate part 2m) while being sheared by the rotation of the screw 11, and is plasticized and melted. The metering zone (front portion 2 f) is sent to the front of the screw 11 and accumulated. A back pressure is applied to the screw 11 by the injection cylinder 15.

  As shown in FIG. 1, the determination processing unit 31 in the weighing process compares the control command value Ccf with the corresponding threshold value Csf and monitors whether or not the control command value Ccf exceeds the threshold value Csf (step S2). . Normally, the control command value Ccf is small when plasticization is normally performed, but the control command value Csf is large when plasticization is insufficient. For this reason, threshold Csf sets the magnitude | size which can detect that it exists in the state in which plasticization is inadequate. In this embodiment, the threshold value 5 [%] is assumed as an example. In this case, 5 [%] means a ratio to the amount of electric power during maximum heating. In the flowchart of FIG. 3, the case of monitoring the heater 3f of the front portion 2f will be described, but the heater 3m of the intermediate portion 2m may be monitored instead of the heater 3f of the front portion 2f, Alternatively, both the heater 3f of the front part 2f and the heater 3m of the intermediate part 2m may be monitored, and determination may be made on the condition that both exceed the corresponding threshold values Csf and Csm, respectively. Therefore, FIG. 1 shows both the front part 2f side and the intermediate part 2m side. However, only one of them may be provided, or both may be provided and selected by the determination processing part 34 when used. As a result of monitoring by the determination processing unit 31, if the control command value Ccf does not exceed the threshold value Csf, it is assumed that normal plasticization has been performed, and therefore the process proceeds to the injection process which is the next process. (Steps S3 and S4). Then, other necessary molding processes such as an injection process and a molded product take-out process are performed (steps S5, S6, S7).

  On the other hand, in the measurement process described above, when the determination processing unit 31 monitors whether or not the control command value Ccf exceeds the threshold value Csf, it is assumed that the control command value Ccf exceeds the threshold value Csf (5 [%]). (Steps S2 and S3). In this case, the determination data based on the excess is given to the determination processing unit 34. Accordingly, the determination processing unit 34 performs one count (step S8). If the control command value Ccf exceeds the threshold value Csf only once, the plasticization abnormality is not determined. That is, since a temporary phenomenon due to the influence of a disturbance or the like is also considered, the judgment processing unit 34 determines that the plasticizing abnormality (plasticization) is performed on the condition that the number of times of the continuous exceeding has reached N times (for example, 3 times). It is determined (temporary determination) that there is insufficient (step S9). As described above, if the control command value Ccf exceeds the threshold value Csf N times continuously, it is determined that the plasticization abnormality is present, so that the influence of the sudden disturbance can be eliminated, and more reliably and reliably. Stable and highly reliable determination can be performed.

  On the other hand, at this time, the determination processing unit 33 compares the rotational torque value Xd of the screw 11 with the threshold value Xs, and determines whether or not the rotational torque value Xd exceeds the threshold value Xs (step S10). In this case, the threshold value Xs is set such that the rotational torque value Xd is out of the normal range. Then, when the determination processing unit 34 counts that the control command value Ccf exceeds the threshold value Csf, it determines whether or not the rotational torque value Xd exceeds the threshold value Xs. Even if the control command value Ccf exceeds the threshold value Csf N times, if the rotational torque value Xd does not exceed the threshold value Xs, it is considered that cold outside air has flowed in and the heating cylinder 2 has been temporarily cooled. Therefore, the determination processing unit 34 gives the first alarm command to the abnormality processing unit 35. Thereby, the display unit 25 performs a necessary caution display such as “There is a possibility of insufficient plasticization” (step S11). As a result, the operator can perform necessary confirmation or the like by means of a caution display.

  On the other hand, when the control command value Ccf exceeds the threshold value Csf N times and the rotational torque value Xd also exceeds the threshold value Xs, there is a high possibility of insufficient plasticization. 34 formally determines that a plasticization abnormality has occurred, and gives a second alarm command to the abnormality processing unit 35. Thereby, the display unit 2 performs a necessary warning display such as “occurrence of plasticization abnormality” (step S12). As described above, when the control command value Ccf exceeds the threshold value Csf, a different alarm is displayed when the rotational torque value Xd of the screw 4 exceeds the preset threshold value Xs or does not exceed the threshold value Xs. Therefore, more appropriate alarm display can be performed by selecting from a plurality of different alarm displays for different results relating to plasticization abnormality.

  Further, a setting change process for changing the target temperature THs corresponding to the rear part 2r of the heating cylinder 2 to a higher temperature is performed. The setting change process uses a technique such as adding a fixed correction value to the current target temperature THs in the correction unit 36 (step S13). If the setting change process for the target temperature THs corresponding to the rear part 2r of the heating cylinder 2 is performed, the plasticization is further promoted before reaching the front part 2f and the intermediate part 2m of the heating cylinder 2, and the plasticization is insufficient. Thus, the plasticizing abnormality can be effectively eliminated, and the determination result by the abnormality determining means Fj can be directly used for countermeasures against abnormality, so that automation can be easily performed. Then, the changed target temperature THs is transferred to the temperature control unit 22. Thereby, the target temperature THs is changed in the temperature controller 22 (step S14).

  Further, the interval processing unit 37 performs an interval process so that the determination by the abnormality determination unit Fj is not performed until a predetermined interval time Ti has elapsed after the target temperature is changed by the setting change unit Fr (step S15). ). Thereby, the erroneous detection in the unstable area after a change can be prevented. Therefore, the interval time Ti can be set to a time until the unstable region after the change is resolved. Such a setting change process may be configured to be automatically executed after a plasticization abnormality is determined, or may be configured to be manually executed. In the case of manual execution, after confirming the warning display, for example, the operator may set the correction amount arbitrarily and then press the execution key or the like.

  In this case, it is important that the control command value Ccf exceeds the threshold value Csf, and the fact that the rotational torque value Xd exceeds the threshold value Xs is an auxiliary determination factor. However, if the plasticizing abnormality is determined on the condition that the rotational torque value Xd of the screw 4 exceeds the preset threshold value Xs when the control command value Ccf exceeds the threshold value Csf, there are two factors. More reliable and various determinations can be performed by the composite determination based on the above. For this reason, various determination modes are possible. For example, when the control command value Ccf exceeds the threshold value Csf N times continuously, if the rotational torque value Xd exceeds the threshold value Xs even once, the second alarm command Or the rotational torque value Xd may exceed the threshold value Xs three times in succession. Therefore, in consideration of safety, the second alarm command is output only when the control command value Ccf exceeds the threshold value Csf three times, that is, without considering the condition that the rotational torque value Xd exceeds the threshold value Xs. Or correction processing may be performed.

  Therefore, according to the control device 1 according to this embodiment, the control command values Ccf and Ccm for the heaters 3f and 3m attached to the front part 2f and / or the intermediate part 2m of the heating cylinder 2 are set to the threshold values Csf and Csm. If there is an excess, the abnormality determination means Fj for determining that the plasticization of the resin is abnormal is eliminated. Therefore, disturbance factors that are not related to the plasticized state are eliminated, and plasticization abnormality, particularly plastic It is possible to accurately grasp that the conversion is insufficient. Therefore, it is most suitable for a recycled material in which chips of various sizes and different shapes are mixed. Further, since the abnormality processing means Fp including the alarm display means Fa for displaying an alarm indicating that the plasticizing abnormality has occurred is provided, the operator can quickly confirm that the plasticizing abnormality has occurred and quickly take necessary measures. It can be carried out.

  As mentioned above, although preferred embodiment was described in detail, this invention is not limited to such embodiment, It does not deviate from the summary of this invention in a detailed structure, a shape, a raw material, quantity, a numerical value, etc. It can be changed, added, or deleted arbitrarily.

  For example, the metering zone of the front part 2f and the compression zone of the intermediate part 2m in the heating cylinder 2 may be integrated, that is, a single heater straddling both may be provided. The control command values Ccf and Ccm and the rotational torque value Xd may be indirect physical quantities as well as directly using them. Therefore, the control command value Ccf can be replaced by another physical quantity as long as it can detect the load of the heater 3f, and the rotational torque value Xd can be replaced by another physical quantity such as work amount and load. On the other hand, in the abnormality determination means Fj, the case where the control command value Ccf, Ccm exceeds the threshold value Csf, Csm is determined to be a plasticization abnormality on condition that the control command value Ccf, Ccm exceeds N times continuously. , Ccm may exceed the threshold values Csf, Csm, and may be determined as plasticizing abnormality on condition that it exceeds the set time. Further, as the abnormality processing means Fp, the alarm display (attention display, warning display) by the alarm display means Fa and the correction processing for the target temperature THs are illustrated, but other abnormality processes are not excluded. Further, the detected temperatures THd are not necessarily limited to the temperatures during the measurement process.

  The control device according to the present invention can be used in various injection molding machines including a heating cylinder heated by a heater.

  DESCRIPTION OF SYMBOLS 1: Control apparatus, 2: Heating cylinder, 2f: Front part, 2m: Middle part, 2r: Rear part, 3f: Heater, 3m: Heater, 3r: Heater, 4: Screw, Fh: Heating cylinder heating means, Fc: Temperature Control means, Fp: abnormality processing means, Fa: alarm display means, Fj: abnormality determination means, Fr: setting change means, THd ...: detected temperature, THs ...: target temperature, M: injection molding machine, Ccf: control command value , Ccm: control command value, Csf: threshold value, Csm: threshold value, Xd: rotational torque value, Xs: threshold value

Claims (6)

  Heating cylinder heating means for heating the heating cylinder by energizing heaters attached to the front metering zone, the intermediate compression zone and the rear feed zone in the heating cylinder, and detection obtained by detecting the temperature of each zone In a control device for an injection molding machine comprising temperature control means for energizing the heater so that the temperature becomes a preset target temperature, a control command for at least the heater attached to the front part and / or the intermediate part Abnormality for determining plastic plasticization abnormality on condition that the value exceeds a preset threshold value and the rotational torque value of the screw exceeds a preset threshold value when the control command value exceeds the threshold value And a warning display for displaying a warning that at least the plasticization abnormality has occurred if the abnormality determination means determines that the plasticization abnormality has occurred. Controller of the injection molding machine, characterized in that it comprises an abnormality processing means including a stage.   The abnormality determining means determines the plasticization abnormality on the condition that when the control command value exceeds the threshold set for the control command value, the control command value exceeds N times or exceeds a set time. The control apparatus for an injection molding machine according to claim 1.   When the control command value exceeds the threshold value set for the control command value, the alarm display means has a magnitude of the rotational torque value that exceeds the threshold value set for the rotational torque value. 2. The control device for an injection molding machine according to claim 1, wherein a different alarm display is performed when the case is not exceeded or not exceeded.   The control apparatus for an injection molding machine according to claim 1, 2 or 3, wherein the abnormality processing means includes setting change means for changing a target temperature for the rear portion to a higher temperature.   5. The control apparatus for an injection molding machine according to claim 4, wherein the abnormality determination unit does not perform determination until a predetermined interval time has elapsed after the target temperature is changed by the setting change unit.   2. The control apparatus for an injection molding machine according to claim 1, wherein the detected temperature is a temperature during a measuring step.

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