JP6206719B2 - Heating barrel temperature control method for injection molding machine - Google Patents

Description

  The present invention relates to a temperature control method for a heating barrel of an injection device of an injection molding machine.

  In the plasticizing / metering step performed in the heating barrel of the injection device of the injection molding machine, a heating unit such as a plurality of band heaters arranged in the longitudinal direction of the outer periphery of the heating barrel, The temperature of each part of the heating barrel corresponding to the supply part (feed zone), compression part (compression zone) and metering part (metering zone), or the temperature of each part obtained by further dividing each part in the longitudinal direction Is appropriately controlled. This is because the pellet-shaped resin material supplied into the heating barrel is heated according to the function of each part, and finally plasticized (melted) and measured in an optimum state. Various control methods for optimally controlling the heating barrel temperature are disclosed.

  For example, in Patent Document 1, in the conventional heating barrel temperature control method, the heat capacity of the nozzle unit set to the highest temperature is the smallest and the heat capacity of the supply unit set to the lowest temperature is the largest. The problem is that the temperature rise time from the start of energization to the means until the set molding temperature is reached is the shortest in the nozzle part and the longest in the supply part. That is, there is a possibility that the molding start waiting time in the nozzle portion set to the highest temperature becomes long, and the resin may be decomposed or burnt (Patent Document 1 / paragraph 0006).

  In the heating barrel temperature control method of Patent Document 1, a secondary set temperature lower than the lowest set temperature is set as the set temperature of each part, and this secondary set temperature is set to the lowest temperature in the nozzle part, and in the supply part By setting the highest temperature, it is possible to shorten the time from reaching the secondary set temperature of each part to reaching the normal set temperature, and to prevent the occurrence of resin defects in the nozzle part (Patent Document 1 / Paragraph 0011).

  In addition, in PID control employed in the conventional heating barrel temperature control method, Patent Document 2 describes the user's factory environment in the PID control constant incorporated in the control means in advance by the injection machine manufacturer and the auto-tuning function of the PID control constant. Since the resin used, the mold temperature, and the set temperature of the heating cylinder are different at the beginning, it is a problem that the temperature overshoot and undershoot phenomena during continuous automatic molding cannot be sufficiently reduced (Patent Document 1 / paragraph). 0008 et al.) Discloses a temperature control device and a temperature control method for an injection molding machine that can solve this problem.

JP-A-8-281754 JP 2006-289781 A

  Before starting the continuous molding operation, the heating means of the heating barrel is energized, and after each part of the heating barrel reaches the respective heating set temperature, the material supply to the supply unit is started and the continuous molding operation is started. Since the resin material to be supplied is normally a pellet-shaped solid material at normal temperature, the flight of the screw in the first half of the supply unit and the adjacent compression unit flows the resin material to the nozzle side by the rotation of the screw. Designed to suit specifications (shape, pitch, etc.). On the other hand, when the heating barrel heats the resin material in the first half of the supply unit and the adjacent compression unit more than necessary, and part of the surface melts, the resin materials adhere to each other and the supply unit and the adjacent compression unit Resin feed failure occurs due to blockage due to bridge formation in the front half, adhesion to the screw in the front half of the supply section and the adjacent compression section, and the like. Therefore, the heating means of the first half of the supply unit and the adjacent compression unit is higher than the temperature of the resin material to be supplied, so that the supplied resin material does not melt in the first half of the supply unit and the adjacent compression unit, The heating set temperature is set lower than the latter half of the compression unit and the metering unit.

  Thus, in the injection molding by a general injection molding machine, the resin material continuously supplied at a room temperature lower than the heating set temperature of the heating barrel is set in advance before the start of the continuous molding operation. The heating barrel in the first half of the supply unit and the adjacent compression unit preheated to the heating set temperature is removed, and the actual temperature falls below the heating set temperature of the heating means, and the first half of the supply unit and the adjacent compression unit Due to insufficient heating of the resin material, it becomes difficult to perform optimal plasticization (melting state) in the compression unit and the measurement unit, resulting in defective resin feed of the entire supply unit, compression unit, and measurement unit. As a result, there is a problem in that the plasticization / measurement process becomes unstable. In addition, in the molding material that easily absorbs moisture, the material is supplied in a state of being dried and heated in advance to such an extent that moisture can be removed. A feed failure occurs.

  However, as in Patent Document 1, in the temperature control method related to preheating of the heating barrel before the start of the continuous molding operation, such heat removal of the injection device system by the resin material continuously supplied at a low temperature is performed. Corresponding control is not envisaged.

  In contrast, in the temperature control device and temperature control method for an injection molding machine disclosed in Patent Document 2, temperature overshoot and undershoot phenomena during continuous automatic molding (continuous molding operation) can be sufficiently reduced. It is supposed to be possible. However, as in Patent Document 2, a temperature detection unit is arranged at each site where the heating unit of the heating barrel is arranged, or in the vicinity of the site where the heating unit is arranged, and the heating barrel itself detected by the temperature detection unit. In the temperature control method in which feedback control of the heating set temperature of the heating means is performed based on the actual temperature, the time lag until each part reaches the intended temperature is large due to the factors described later, and the temperature control of each part is performed. There is a problem that it is difficult. Further, due to this time lag, there is a problem that the temperature of each detected part does not necessarily match the temperature of the resin material in each corresponding part.

  Here, in the control method of the heating barrel, the reason why the time lag until each part reaches the intended temperature is large and the temperature of each part does not match the temperature of the resin material in each corresponding part will be briefly described. . In the plasticizing / metering process in the heating barrel, the pellet-shaped resin material supplied from the supply section is sheared and kneaded by the rotating screw flight in the resin flow path between the inner wall of the heating barrel and the screw. By making the shear heat energy directly applied to the resin material, and from the heating means disposed on the outer peripheral surface of the heating barrel, the thermal energy indirectly applied to the resin material through the heating barrel, It is plasticized by two types of thermal energy. In contrast to the former shear energy, the heat energy of the latter heating means cannot directly heat the resin material in the heating barrel. This is the main cause of the time lag described above.

  That is, the heat energy by the heating means first heats the heating barrel itself, and the resin that is in direct contact with the heated heating barrel is heated only by contact heat transfer. Here, heating of the resin material having low thermal conductivity with respect to the metal material constituting the heating barrel or the like requires a heating time longer than that of the heating barrel. On the other hand, although the resin material is also heated by the former shear energy, the thermal energy is transferred to each other depending on the temperature relationship at the position of the resin material with respect to the temperature of the screw with which the resin material is in contact.

  Thus, the heating barrel directly heated by the heating means, the resin material with low thermal conductivity heated by the heating barrel, the screw heated by contact with the resin material, and the transfer of these thermal energy Only when the thermal energy transfer between various parts and the resin material occurs and the transfer of the thermal energy is saturated, the temperature of each part of the heating barrel itself and the temperature of the resin material in each corresponding part are stabilized. . Therefore, the time lag until the movement of the heat energy as described above is saturated, that is, the time lag until the resin material in each part or the corresponding part reaches the heating set temperature of each heating means is large. Moreover, the actual temperature of each part detected before the above-mentioned movement of thermal energy is saturated is different from the actual temperature at which each part is finally saturated. Naturally, the actual temperature of the resin material before saturating does not match the temperature of each part detected before saturating. Although the above has described the case where the temperature of the heating barrel is raised, the same applies to the case where the temperature is lowered.

  On the other hand, there is a similar problem when the continuous molding operation of the injection molding machine is stopped. When the supply of the resin material to the injection device is stopped after satisfying a predetermined molding cycle end condition, the resin material in the heating barrel is usually removed even after the supply of the resin material is stopped in view of the next operation. In order to completely discharge (purge), the plasticizing / metering process is continued (purge process). Unlike the normal plasticizing / metering step, this purging step is performed in a state where the injection device is retracted and the nozzle portion of the heating barrel is separated from the fixed mold. Specifically, after placing a purge resin receptacle or the like in the nozzle part, the rotation operation is performed while the screw is advanced to the screw advance limit position or the vicinity thereof at the completion of the injection process of the previous molding cycle, and heating is performed. All of the resin material in the barrel is plasticized and continuously discharged from the nozzle without being stored in the storage portion.

  In this purge process, the amount of the resin material in the heating barrel is gradually purged and reduced, whereas if the heating setting temperature of each heating means is constant, the total amount of heat energy applied to the heating barrel Is constant and does not change. Therefore, the thermal energy applied to the resin material in the heating barrel becomes excessive, and the resin material remaining in the heating barrel is baked into the screw or carbonized, so that the heat in the heating barrel before the operation is resumed. There is a problem that cleaning takes time. Feedback control based on the actual temperature of each part of each heating means detected by the temperature detection means, even if temperature correction control is performed to gradually lower the temperature of the heating barrel as the resin material in the heating barrel decreases. As long as this is the case, the time lag as described above cannot be avoided, and it is difficult to solve the problem.

  The present invention has been made in view of the above-described problems. Specifically, the correction start point is preset based on the actual temperature of each part of each heating unit detected by the temperature detection unit. It is an object of the present invention to provide a heating barrel temperature control method for an injection molding machine that controls the temperature of the heating barrel based on the temperature correction equation.

In order to achieve the above object, according to the present invention, there is provided a heating barrel temperature control method for an injection molding machine, wherein a plurality of heating means arranged in the longitudinal direction of the heating barrel of the injection device of the injection molding machine are independent of each other. In the heating barrel temperature control method of the injection molding machine controlled by
In the relationship of Tm ≧ Tzx, the target plasticizing resin temperature Tm of the resin to be injected and the initial heating setting temperature Tzx set in each of the heating means disposed in the range of the plasticizing screw supply unit and the compression unit are as follows: Heating setting for setting the heating setting temperature correction value ΔTzx for one correction of each heating means by an expression ΔTzx = α (Tm−Tzx) using α set in a range of 0.1 ≦ α ≦ 1. Temperature correction preparation process;
The first correction start point 1 is a point in time when at least one difference in the weighing time, the molded product weight, and the average rotational load factor of the screw exceeds a preset allowable amount Q1,
The difference is compared with the allowable amount Q1 at a predetermined time T1 set in advance from the first correction start point 1, and the time when the difference exceeds the allowable amount range is determined for the second and subsequent times. The correction start point is 1,
At the correction start point 1 set in advance, the new heating set temperature T′zx is reset by the temperature correction formula 1, T′zx = Tzx + ΔTzx, and each time the next correction start point 1 is reached, The left side of the temperature correction formula 1 is based on the temperature correction formula 1 in which the right side Tzx of the temperature correction formula 1 is replaced with the new heating set temperature T′zx reset at the previous correction start point 1. Heating set temperature correction step 1 for gradually increasing the temperature T'zx of
Have

Further, according to the present invention, the correction start point in the heating barrel temperature control method of the injection molding machine, from said first correction start point 1 is carried out every predetermined time T1 is set in advance, the difference between the allowable amount comparison with Q1 are each molding cycle, or, it is preferable that the Ru performed every molding cycle more than once.

  Furthermore, in the heating barrel temperature control method for an injection molding machine according to the present invention, when the new heating set temperature T′zx satisfies Tm + (Tm−Tzx) ≧ T′zx ≧ Tm, It is preferable to finish the heating set temperature correction step 1.

  Next, in the heating barrel temperature control method for an injection molding machine according to the present invention, at the correction start point 1 in the heating set temperature correction step 1, the molding cycle is stopped before a predetermined time T2 from the scheduled stop of the molding cycle. At the molding cycle stop preparation correction start point including the preparation correction start point, the temperature correction formula 1 is switched to the temperature correction formula 2, T ″ zx = T′zx−ΔTzx, and the new heating set temperature T ″ zx And the correction start point 2 after the molding cycle stop preparation correction start point after the predetermined time T3, and every time the next correction start point 2 is reached, based on the temperature correction formula 2, A heating set temperature correction step 2 for gradually lowering the new heating set temperature may be further included.

  Similarly, in the heating barrel temperature control method for an injection molding machine according to the present invention, when the difference exceeds a preset allowable amount Q2 in the heating set temperature correction step 1, the temperature correction formula 1 May be switched to the temperature correction formula 2, and the new heating set temperature may be gradually decreased.

On the other hand, according to the present invention, heating barrel temperature control method of the injection molding machine, the heating setting temperature correction step 1, or, said have you to heat set temperature correction step 2, initial newly set change during the molding cycle The heating preset temperature correction preparation step, the heating preset temperature correction step 1, or the heating preset temperature correction step 2 may be performed based on the heating preset temperature Tzx or the target plasticizing resin temperature Tm.

In the heating barrel temperature control method for an injection molding machine according to the present invention, the plurality of heating means arranged in the longitudinal direction of the heating barrel of the injection device of the injection molding machine are independently controlled. In the heating barrel temperature control method of
The target plasticization resin temperature Tm of the resin to be injected and the initial heating set temperature Tzx set in each heating means arranged in the range of the screw supply unit and the compression unit are in the relationship of Tm ≧ Tzx. Heating set temperature correction for setting the heating set temperature correction value ΔTzx for one correction of the heating means using α set in a range of 0.1 ≦ α ≦ 1 by the expression ΔTzx = α (Tm−Tzx) A preparation process;
The first correction start point 1 is a point in time when at least one difference in the weighing time, the molded product weight, and the average rotational load factor of the screw exceeds a preset allowable amount Q1,
The difference is compared with the allowable amount Q1 at a predetermined time T1 set in advance from the first correction start point 1, and the time when the difference exceeds the allowable amount range is determined for the second and subsequent times. The correction start point is 1,
At the correction start point 1 set in advance, the new heating set temperature T′zx is reset by the temperature correction formula 1, T′zx = Tzx + ΔTzx, and each time the next correction start point 1 is reached, The left side of the temperature correction formula 1 is based on the temperature correction formula 1 in which the right side Tzx of the temperature correction formula 1 is replaced with the new heating set temperature T′zx reset at the previous correction start point 1. Heating set temperature correction step 1 for gradually increasing the temperature T'zx of
Therefore, the temperature control of the heating barrel can be performed based on the preset correction start point and the temperature correction formula, not based on the actual temperature of each part of each heating means detected by the temperature detecting means. .

It is a schematic sectional drawing which shows the heating barrel and heating means of an injection molding machine. It is a graph which shows the image of the situation where the heating barrel pre-heated to heating preset temperature is heat-removed with the resin material supplied, and each site | part becomes below the heating preset temperature of each heating means. It is a graph which shows the image of temperature rising of the heating barrel by the heating preset temperature correction process 1 in the site | part H3. It is a graph which shows the image of the temperature fall of the heating barrel by the heating preset temperature correction process 2 after the shaping | molding cycle stop preparation correction start point in the site | part H3.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited to said embodiment, It can implement with various methods in the range shown to a claim.

  A heating barrel temperature control method for an injection molding machine according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3. The heating barrel temperature control method for an injection molding machine according to the present invention does not require a special configuration on the injection molding machine side, and can be implemented using a general injection molding machine. Therefore, first, referring to FIG. 1, the basic configuration of the heating barrel 10 of the injection device of a general injection molding machine and the plasticizing / metering process (hereinafter referred to as “metering process”) performed in the heating barrel 10 can be simplified. explain.

  A conical screw head 22 is fixed to the tip of the screw 21 in the heating barrel 10. A ring-shaped check valve 24 (also referred to as a check ring or the like) is disposed in the screw head 22 so as to be movable by a predetermined amount in the longitudinal direction of the screw head 22.

  Moreover, the nozzle part 12 and the storage part 11 are formed in the heating barrel 10 from the left side (henceforth: front) of FIG. A screw 21 on the right side (hereinafter: rear) of the check head 24 of the screw head 22 is arranged from the check valve 24 side (front) to a metering unit (metering zone), a compression unit (compression zone), and a supply unit. The screw 21 is divided into three parts called “feed zones”, and the spiral flight 21 a is continuously formed on the outer peripheral surface of the screw 21 over the entire length thereof. The shape and pitch of the flight 21a are designed with specifications suitable for the function of each part (zone).

  Furthermore, on the outer peripheral surface of the two parts of the nozzle part 12 and the storage part 11 of the heating barrel 10, and on the outer peripheral surface of the heating barrel 10 corresponding to the three parts of the measuring part, the compression part and the supply part of the screw 21, A heating unit Hn, a heating unit H0, a heating unit H1, a heating unit H2, and a heating unit H3 for heating each part are arranged. In order to simplify the explanation, the outer peripheral surface of the heating barrel 10 on which each of these heating means is arranged is also the part Hn (nozzle part 12), the part H0 (storage part 11), the part H1 (metering part), and the part H2. (Compression part) and the part H3 (supply part) shall be called. In the first embodiment, in order to simplify the description, one heating unit is provided in each part of the heating barrel 10, but each part is further divided in the longitudinal direction as described above. A form in which a plurality of heating means are arranged in each divided part may be used.

  During the weighing process, the pellet-shaped resin material supplied into the heating barrel 10 from the material supply unit 13 at the upper rear of the heating barrel 10 is rotated by the rotation of the screw 21 in which the spiral flight 21a is formed on the outer peripheral surface thereof. In the resin flow path 14 formed between the inner peripheral surface of the heating barrel 10 and the outer peripheral surface of the screw 21, the fluid flows toward the storage unit 11 (forward). Meanwhile, 2 of the heat energy from the heating means Hn to the heating means H3 and the shear energy (heat energy) directly applied from the flight 21a to the resin material by the rotation of the screw 21 disposed on the outer peripheral surface of the heating barrel 10. Plasticized by different types of thermal energy.

  The check valve 24 is pressed toward the storage unit 11 by the resin pressure generated by the resin flow, and between the check valve 24 moved to the storage unit 11 side (forward limit position) and the screw 21. Is released. Further, in this state, the resin flow path 14 that is opened and a recess (not shown) in the longitudinal direction of the screw head 22 communicate with each other, and the plasticized resin in the resin flow path 14 of the screw 21 is stored in front of the screw head 22. It is continuously stored in the part 11.

Moreover, with the increase in the amount of resin stored in the storage unit 11 during the weighing process, the screw 21 is
While maintaining the rotational operation, the material is pressed and moved toward the material supply unit 13 (rearward) (screw retraction operation). The screw retreating operation is performed in a state where a resistance force (back pressure) accompanying the retreating operation is applied to the screw 21 in order to apply a predetermined pressure to the plasticized resin stored in the storage unit 11. Then, after a preset amount of plasticized resin is stored in the storage unit 11, the material supply to the material supply unit 13 and the rotation operation of the screw 21 are stopped (the measurement process is completed).

  Thereafter, the process proceeds to an injection process in which the screw 21 is advanced at a predetermined speed and a predetermined pressure. In the injection process, the resin flow path 14 is closed when the front end of the screw 21 that moves forward contacts the rear end of the check valve 24 that does not follow the forward movement of the screw 21, and the check valve 24 remains as it is. Subject to increasing resin pressure of the 11 side plasticized resin. The check valve 24 that is pressed toward the screw 21 prevents the plastic resin from flowing backward from the storage portion 11 to the resin flow path 14 on the screw 21 side. Since the heating barrel temperature control method of the injection molding machine according to the present invention is not directly related to the temperature control of the heating barrel during the injection process, a detailed description of the injection process is omitted.

  As described above, in the weighing process, the heating barrel 10 preheated to a preset heating set temperature is removed by the resin material continuously supplied at a low temperature before the start of the continuous molding operation. Heated, the actual temperature of each part is below the heating set temperature of each heating means, the greater the amount of resin material supplied, the longer the metering time, the shorter the molding cycle, the greater the degree of heat removal The heating barrel is not heated in time by the heating means, and the actual temperature of each part is greatly reduced. When the degree of heat removal and the heating by the heating means are in an equilibrium state, the actual temperature of each part is saturated in a greatly lowered state. This is shown in FIG. FIG. 2 is a graph showing an image of a situation in which the heating barrel preheated to the heating set temperature is removed by the supplied resin material, and each part becomes equal to or lower than the heating set temperature of each heating means. The horizontal axis in FIG. 2 indicates each part (part H0, part H1, part H2, and part H3) in the heating barrel 10, and the vertical axis indicates the temperature.

As shown in FIG. 2, the initial heating set temperature Tzx of each heating means up to the reservoir 11 (part H0), the metering part (part H1), the compression part (part H2), and the supply part (part H3) is respectively , Tz ₀ , Tz ₁ , Tz ₂ and Tz ₃ . With respect to the target plasticization resin temperature Tm of the resin to be injected, the heating setting temperature Tz ₀ of the heating means H0 of the storage part 11 (part H0) and the heating setting temperature Tz ₁ of the heating means H1 of the measuring part (part H1) are As shown in FIG. 2, the same temperature as Tm is set. And the heating setting temperature of each site | part behind this is set so low that it is close to a supply part (part H3). That is, the relationship between the heating set temperatures of the respective parts is generally set to Tm = Tz ₀ = Tz ₁ > Tz ₂ > Tz ₃ .

However, the heating barrel 10 is removed by the resin material that is continuously supplied at a low temperature, and the closer to the supply portion (part H3) that has a large heat removal effect, the greater the decrease in the actual temperature at each part. . On the other hand, since there is almost no influence of the heat removal action on the heating barrel by the resin material after the resin material is plasticized (melted), the storage part 11 (part H0) or the metering where the plasticization of the resin material is completed There is little influence of the heat removal action in the second half of the part (part H1) and the compression part (part H2) where plasticization proceeds. Therefore, in FIG. 2, the influence of the heat removal effect in the storage part 11 (part H0) and the measuring part (part H1) is assumed to be negligible, and the actual temperature of the supply part (part H3) is reduced to Tb ₃ until the compression part ( the actual temperature of the portion H2) indicates that the lowered to Tb ₂ (dotted _{line: Tz 3 -Tb 3> Tz 2} -Tb 2). In addition, about the nozzle part 12 (part Hn), although temperature control independent of another site | part is also possible, the influence of the heat removal effect | action can be disregarded similarly to the storage part 11. FIG.

  As described above, in the process in which the actual temperature of each part of the heating barrel 10 is removed in the measuring step for each molding cycle and the temperature is lowered to the heating set temperature of the corresponding heating means, the resin material is in a plasticized state. Since the total amount of heat energy supplied until the time is reduced, the plasticized state of the resin material becomes unstable. Then, when the amount of decrease in the heat capacity of the heating barrel 10 due to the temperature drop of each part of the heating barrel 10 and the amount of heat removed by the supplied resin material are saturated, unless any temperature correction control is performed on the heating set temperature of each heating means. The temperature of each part is saturated at a temperature lower than the heating set temperature of each heating means. As a result, the resin material flows to the compression part and the weighing part in an unexpectedly softened / molten state, resulting in poor resin feed and the like, leading to instability of the weighing process.

  Even if this state is feedback controlled based on the actual temperature of each part of each heating means detected by the temperature detecting means, it is difficult to control the temperature of the heating barrel as intended due to the time lag described above. As described in the above. On the other hand, if a large temperature control width that reduces such a time lag is set for the heating set temperature of each heating means, and if the actual temperature of each part of the heating barrel 10 is forcibly feedback controlled, the target control temperature The hunting width from the side becomes large, and there is a possibility that the weighing process becomes unstable.

  Next, a heating barrel temperature control method for an injection molding machine according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 3 is a graph showing an image of the temperature rise of the heating barrel in the heating set temperature correction step 1 in the part H3. The horizontal axis in FIG. 3 indicates elapsed time, and the vertical axis indicates temperature. In the first embodiment, the control method of the heating set temperature of each heating means in each part is basically the same, so that the heating barrel temperature of the injection molding machine according to the present invention represents the part H3 (supply unit). A control method will be described.

First, before starting the continuous molding operation, the target plasticization temperature Tm of the resin to be injected, the initial heating set temperature Tzx of each heating means, etc. are input to the control means of an injection molding machine (not shown) from an interface such as an operation panel. To do. In the control means, in the relationship of Tm ≧ Tzx, the heating set temperature correction value ΔTzx for each heating means is automatically set by the expression ΔTzx = α (Tm−Tzx) (heating set temperature correction preparation step). ). In the part H3 (supply unit), the initial heating set temperature of the heating unit H3 is Tz ₃ (Tm> Tz ₃ ), and the heating set temperature correction value ΔTz ₃ for one correction is ΔTz ₃ = α (Tm−Tz ₃ ). .

  In this heating set temperature correction preparation step, an allowable amount Q1 and a predetermined time T1 are input. The permissible amount Q1 is a permissible amount of difference in at least one of the measurement time, the weight of the molded product, and the average rotational load factor of the screw monitored for each molding cycle for setting the first correction start point 1. . These items monitored for each molding cycle are compared for each molding cycle, and a difference is obtained. The time when at least one of these differences exceeds the allowable amount Q1 of the corresponding item is the first correction start point 1. Recognized by the control means of the injection molding machine.

  After the first correction start point 1, these items are compared with the previous molding cycle for each molding cycle, and the time when the difference of at least one of these differences again exceeds the allowable amount Q1 is set as the next correction start point 1. good. Further, these items are compared at every elapse of a predetermined time T1 from the first correction start point 1, and the time when the difference of at least one of the differences again exceeds the allowable amount Q1 may be set as the subsequent correction start point 1. . Specifically, instead of the weighing time for each molding cycle, the weight of the molded product and the average rotational load factor of the screw, the relationship of the retraction amount of the screw 21 within a minute time in the weighing process during one molding cycle, that is, The reverse speed of the screw 21 and the average rotational load factor of the screw within a minute time are monitored every predetermined time T1 to obtain the difference, and the time when the corresponding allowable amount Q1 is exceeded corresponds to the subsequent correction start point. It may be 1.

  On the other hand, without comparing these items for each molding cycle, an input is made so that the predetermined time T1 is two or more molding cycles, and after the first correction start point 1, each of the molding cycles is corrected thereafter. It may be the starting point 1.

  The allowable amount Q1 and the predetermined time T1 are preferably obtained by performing test molding in advance according to the type of resin to be injected, the amount of metered resin, the molding cycle, and the like. Further, the range of α in the equation ΔTzx = α (Tm−Tzx) for setting the heating set temperature correction value ΔTzx is preferably 0.1 ≦ α ≦ 1. The reason will be described later. It is more preferable that the various set values in the heating set temperature correction preparation step are modified from the initial values to more suitable values based on knowledge obtained from subsequent injection molding and experience.

  Thus, the correction start point 1 is not the actual temperature of each part of the heating barrel, but the difference in at least one item of the weighing time, the molded product weight, and the average rotational load factor of the screw for each molding cycle, or one This relates to the difference in at least one item of the retraction speed of the screw 21 and the average rotational load factor of the screw within a minute time within the molding cycle. The average rotational load factor of the screw is an item deeply related to the shear heat energy directly applied to the resin material as described above, and the measurement time, the weight of the molded product, and the screw 21 replaced by this. Therefore, the time lag is less with respect to the actual temperature of each part of the heating barrel in order to grasp the plasticized state of the resin material in the heating barrel 10. Therefore, by setting the correction start point 1 as described above, a new heating set temperature of each heating unit can be reset at an appropriate timing.

After the heating set temperature correction preparation process is completed and each part of the heating barrel 10 reaches the initial heating set temperature Tzx, the screw 21 is rotated to start the material supply to the material supply unit 13 to perform continuous molding. Start driving. As shown in FIG. 3, in the feed unit (site H3), the initial heating set temperature Tz ₃ of the heating unit H3, while the actual temperature (dotted line) was cooled to Tb ₃ sites H3 of the heating barrel 10 is there. It is assumed that the plasticization state of the solid resin material changes due to this temperature decrease, and the first correction start point 1C1 is recognized by the control means of the injection molding machine.

The heating set temperature correction step 1 is started by recognizing the first correction start point 1C1. In the heating setting temperature correction preparatory process, the control means of the injection molding machine uses each ΔTzx set by the equation ΔTzx = α (Tm−Tzx) in advance and the temperature correction equation 1, T′zx = Tzx + ΔTzx. The new heating setting temperature T′zx is reset, and the heating setting temperature of each heating means is increased from the initial heating setting temperature Tzx to T′zx by ΔTzx. The new heating set temperature of the part H3 is T′z ₃ = Tz ₃ + ΔTz ₃ . The Atsushi Nobori of the heating setting temperature of the heating means H3 (corrected), the actual temperature Tb ₃ sites H3 also increases the degree equivalent to ΔTz _3. Here, the heating barrel temperature control method according to the first embodiment is not intended to control the increase range of the actual temperature of each part, but recovers each part of the temperature lowered from the state with a minimum time lag, thereby stabilizing plasticity. The goal is to recover to the normalization state as soon as possible.

After the first correction start point 1C1, if the actual temperature rise of each part is not sufficient and the second correction start point 1C2 is recognized by the control means of the injection molding machine, the temperature correction formula 1, T′zx = With Tzx + ΔTzx, a new heating set temperature for each heating unit is set again. At this time, T′zx on the left side of the temperature correction formula 1 is not the new heating set temperature T′zx set at the first correction start point C1, but is set at the second correction start point and further new heating is performed. Needless to say, this is the set temperature T'zx. Similarly, Tzx on the right side of the temperature correction formula 1 is not the initial heating setting temperature Tzx but a new heating setting temperature T′zx set at the first correction start point 1C1. By raising the temperature of the second heating set temperature of the heating means H3 (correction), once again rises to an extent equivalent to the actual temperature Tb ₃ also DerutaTz ₃ parts H3.

  As described above, in the heating set temperature correction step 1 of the heating barrel temperature control method according to the first embodiment, each time the correction start point 1 is recognized, each heating means is based on the correction amount ΔTzx and the temperature correction formula 1. The heating set temperature is reset, and the heating set temperature of each heating means is raised stepwise regardless of the actual temperature of each part corresponding to each heating means. As a result of this temperature increase, the actual temperature of each part corresponding to each heating means also rises in a step-like manner, and approaches the originally set initial heating set temperature Tzx of each heating means.

  Further, in the heating set temperature correction step 1 of the heating barrel temperature control method according to the first embodiment, the new heating set temperature T′zx reset at the correction start point 1 regardless of the number of correction start points 1. However, it is preferable to finish the correction at the time when Tm + (Tm−Tzx) ≧ T′zx ≧ Tm is first satisfied. By setting the upper limit of the heating set temperature of the heating means to be reset as the target plasticizing resin temperature Tm of the resin to be injected, it can be set regardless of experience or intuition. In addition, by setting a temperature control width that is larger than necessary, it is possible to prevent the material feeding failure due to melting of the molding material due to excessive heating in the supply unit.

FIG. 3 shows a case where the condition for completing the correction is T′z ₃ = Tm. Specifically, a new heating set temperature is reset at the four correction start points 1 and the heating set temperature correction step 1 is completed at the fourth correction start point 1C4 (T′z ₃ = Tm). ). Moreover, the actual temperature Tb ₃ sites H3 of the time this has risen to a temperature close to the initial heating set temperature Tz ₃ of the heating unit H3. However, as described above, in the first embodiment, when the heating set temperature correction step is completed, the actual temperature Tb ₃ of the portion H3 and the initial heating set temperature Tz _{3 of the} heating unit H3 are not necessarily Tb _3. = Tz ₃ or Tb ₃ ≈Tz ₃ is not necessary. Further, when the heating temperature correction process is completed, the new heating set temperature T′z ₃ may be higher than the target resin temperature Tm (T′z ₃ > Tm).

  That is, the heating barrel temperature control method according to the first embodiment is implemented for the heat removal of the heating barrel 10 by the supplied resin material that occurs after the start of the continuous molding operation, and finally the correction start point 1 It suffices if the continuous molding operation that does not occur continues. In other words, the state in which the correction start point 1 does not occur means that the heating barrel 10 has recovered from the heat removal state, and the resin material is in a stable plasticized state within an appropriate actual temperature range. The actual temperature Tbx of each part of the heating barrel 10 that has a large time lag with respect to the increase / decrease in the heating set temperature Tzx of each heating means does not necessarily match the actual temperature of the resin material even if it becomes a guideline for control. It can be said that it is an element that is not suitable for taking in the control of the heating set temperature of the heating means.

  As described so far, in the heating barrel temperature control method of the injection molding machine according to the first embodiment, the heating setting temperature of each heating unit is not the actual temperature of the heating barrel 10 but a preset correction start point 1. Therefore, a new heating set temperature of each heating means can be set at an appropriate timing without being affected by the time lag of the temperature change of the entire injection apparatus system. Further, in the temperature correction formula 1 for setting a new heating set temperature, the heating set temperature correction value ΔTzx for one correction is set to the target plasticizing resin temperature Tm of the resin to be injected and the initial heating setting set for each heating means. Since it is a numerical value based on the temperature Tzx, it can be set regardless of experience and intuition, and it is possible to change this numerical value to an appropriate numerical value according to the actual molding situation only by changing the coefficient α multiplied by this numerical value. it can.

  Here, the reason why it is preferable to satisfy 0.1 ≦ α ≦ 1 in the range of the coefficient α related to the heating set temperature correction value ΔTzx for one correction in the temperature correction formula 1 will be described. The heating set temperature correction value ΔTzx is a coefficient by which a difference between the target plasticizing resin temperature Tm of the resin to be injected and the initial heating set temperature Tzx set for each heating means is multiplied by these temperatures in the relationship of Tm ≧ Tzx. It is. Therefore, as described above, when the correction value for one time exceeds such a difference (that is, α ≧ 1), there is a high possibility that the hunting width is increased in terms of control.

  Therefore, when large correction is required in this way, it is preferable to increase the number of corrections by appropriately setting the correction start point 1 rather than increasing the correction value for one time. Specifically, the allowable amount Q1 may be set in a narrower range together with the predetermined time T1. On the other hand, when the correction value for one time is a correction value that greatly falls below such a difference (that is, α <0.1), the effect of one correction is small. In addition, there is a limit to the number of corrections to deal with by increasing the number of corrections. In view of these, the range of α of the heating set temperature correction value ΔTzx is set to 0.1 ≦ α ≦ 1, and the heating set temperature correction step is performed by appropriately setting the predetermined time T1 and the allowable amount Q1. Preferably, it is done.

  Further, in the heating barrel temperature control method 1 of the injection molding machine according to the first embodiment, during the molding cycle, the operator of the injection molding machine checks the molded product and initially sets the numerical value according to the situation. Thus, even if the initial heating set temperature Tzx and the target plasticizing resin temperature Tm are changed, the heating setting temperature described above is based on the newly input initial heating setting temperature Tzx and the target plasticizing resin temperature Tm. Needless to say, the correction step 1 is performed. Of course, the setting change during the molding cycle of the above-described α, the allowable amount Q1, and the predetermined time 1 is also included in this.

  Next, an injection molding method according to Example 2 of the present invention will be described with reference to FIG. FIG. 4 is a graph showing an image of the temperature drop of the heating barrel in the heating setting temperature correction step 2 after the molding cycle stop preparation correction start point in the portion H3.

  The heating barrel temperature control method 2 according to the second embodiment is different from the heating barrel temperature control method 1 according to the first embodiment in that temperature correction control (temperature increase) with respect to heat removal from the heating barrel at the start of the continuous molding operation. Rather, the temperature correction control (temperature decrease) is performed on the heated barrel heated by the heated barrel temperature control method 1 according to the first embodiment when the molding cycle is stopped in advance determined by the number of moldings. Similar to the first embodiment, the heating barrel temperature control method according to the second embodiment in the heating barrel 10 of the injection device of a general injection molding machine will be described focusing on the differences from the first embodiment.

  There are two types of operation when the molding cycle is stopped. First, in view of the next operation, after the supply of the resin material is stopped, in order to discharge (purge) all the resin material in the heating barrel 10, the stop is performed in the purge process in which the measurement process is continued. Driving. The other is a stop operation in which, for example, when the next operation is performed with the same resin material, the resin material in the heating barrel 10 is not discharged but is stopped as it is. In the former case, as described above, the amount of the resin material in the heating barrel 10 is gradually purged and decreased. The total amount of thermal energy applied is constant and does not change. Therefore, it is indispensable to gradually lower the heating set temperature of each heating means so that the thermal energy applied to the resin material in the heating barrel 10 does not become excessive. In the latter case, there is an increased risk of defective feeding of the resin material due to excessive heating of the resin material remaining in the heating barrel 10. In particular, when the heating temperature correction step 1 is completed, the new heating set temperature T′zx is higher than the target resin temperature Tm at the time of injection (T′zx> Tm). Increases nature. For this reason, it is essential to gradually lower the heating set temperature of each heating means.

  A heating barrel temperature control method (temperature decrease) of an injection molding machine according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a graph showing an image of the temperature drop of the heating barrel in the heating setting temperature correction step 2 after the molding cycle stop preparation correction start point in the portion H3. The horizontal axis of FIG. 4 shows elapsed time, and the vertical axis shows temperature. Since the control of the heating set temperature of each heating means in each part is basically the same, the heating barrel temperature control method for an injection molding machine according to the present invention will be described on behalf of the part H3 (supply part). is there.

  Prior to the start of the continuous molding operation, the target plasticization temperature Tm of the resin to be injected and the initial heating set temperature Tzx for each heating means are input to the control means of an injection molding machine (not shown) from an interface such as an operation panel. In the control means, the heating set temperature correction value ΔTzx for one correction for each heating means is automatically set by the formula ΔTzx = α (Tm−Tzx) (heating set temperature correction preparation step). Same as Example 1. The same applies to the premise of the relationship of Tm> Tzx.

  Next, in the second embodiment, the predetermined time T2 and the predetermined time T3 are input in this heating set temperature correction preparation step. By the input of the former predetermined time T2, the molding cycle stop preparation correction start point C'1 is set. The molding cycle stop preparation correction start point C'1 is a point at which temperature correction control (temperature decrease) is started for the heated barrel 10 that has been heated, a predetermined time T2 before the molding cycle is scheduled to stop. Further, the correction start point 2 is set by the latter input of the predetermined time T3. The correction start point 2 is a point at which temperature correction control (temperature decrease) is performed on the heated barrel 10 after the molding cycle stop preparation correction start point C′1, and after the molding cycle stop preparation correction start point C′1. The correction start point 2 is recognized every predetermined time T3 by the control means of the injection molding machine, and this temperature correction control (temperature decrease) is repeated for each correction start point 2 until the molding cycle is completed.

  It is assumed that during the continuous molding operation, a predetermined time T2 is reached from the scheduled stop of the molding cycle, and the molding cycle stop preparation correction start point C'1 is recognized by the control unit of the injection molding machine.

The heating set temperature correction step 2 is started by recognizing the molding cycle stop preparation correction start point C′1. In the heating set temperature correction step 2 after the molding cycle stop preparation correction start point C′1, ΔTzx set in advance in the heating set temperature correction preparation step is left as it is, and the temperature correction formula 1 for increasing the temperature, T ′. zx = Tzx + ΔTzx is switched to a temperature correction formula 2 for lowering temperature, T ″ zx = T′zx−ΔTzx. By this temperature correction formula 2, a new heating set temperature T ″ zx of each heating means is obtained. The heating set temperature of each heating means is reset, and the temperature is lowered from the heating set temperature T′zx to T ″ zx at the molding cycle stop preparation correction start point C′1. The new heating set temperature of the part H3 is T ″ z ₃ = T′z ₃ −ΔTz ₃ . The cooling of the heat setting temperature of the heating means H3 (corrected), the actual temperature Tb ₃ sites H3 also lowered to an extent equivalent to ΔTz _3.

  The heating barrel temperature control method before stopping the molding cycle according to the second embodiment is not intended to control the decrease width of the actual temperature of each part. The purpose is to prevent excessive heat energy from being applied to the resin material inside.

  After the molding cycle stop preparation correction start point C′1, which is the first correction start point in the temperature correction control (temperature decrease) of the second embodiment, the second and subsequent correction start points 2 (second correction) every predetermined time T3. Start point 2C′2, the third correction start point 2C′3...) Are recognized, and a new heating set temperature T of each heating means is obtained by the temperature correction formula 2, T ″ zx = T′zx−ΔTzx. “Zx is reset one after another. At this time, T ″ zx on the left side of the temperature correction formula 2 is set not at the new heating set temperature T ″ zx set at the molding cycle stop preparation correction start point C′1 but at the second correction start point 2C′2. Needless to say, this is a new heating set temperature T ″ zx.

Similarly, T′zx on the right side of the temperature correction formula 2 is not the heated heating set temperature T′zx but the new heating set temperature T ″ zx set at the molding cycle stop preparation correction start point C′1. there. the heating of the second heating set temperature of the heating means H3 (correction) again descends to an extent equivalent to the actual temperature Tb ₃ also DerutaTz ₃ parts H3.

  Thus, in the heating set temperature correction step 2 of the heating barrel temperature control method according to the second embodiment, every time the correction start point 2 is recognized after the molding cycle stop preparation correction start point C′1, the correction is performed. Based on the amount ΔTzx and the temperature correction formula 2, the heating setting temperature of each heating unit is reset, and the heating setting temperature of each heating unit is set stepwise regardless of the actual temperature of each part corresponding to each heating unit. Let the temperature drop. Due to this temperature decrease, the actual temperature of each part corresponding to each heating means also decreases stepwise.

  In FIG. 4, the purge process is completed and the molding cycle is completed at time Tf after resetting a new heating set temperature at the correction start point 2C′3 three times. Note that the time Tf is deleted when the molding cycle is stopped without the purge step. The actual temperature Tb3 of the part H3 at this time is also lowered to the extent that the temperature of the heating setting temperature of the heating unit H3 after the molding cycle stop preparation correction start point C′1 is met. As described above, the heating set temperature T ″ zx of each heating unit at the completion of the molding cycle does not necessarily have to be T ″ zx = Tzx or T ″ zx≈Tzx.

  As described above, in the heating barrel temperature control method of the injection molding machine according to the second embodiment, the molding cycle stop preparation correction start point C ′ is determined from a predetermined molding cycle completion timing and a predetermined time T2. If the temperature correction control (temperature decrease) of each heating means is not performed as it is, the plasticization failure that may occur is not the actual temperature of the heating barrel 10, but a correction start point 2 set in advance. Since the resetting is performed at a predetermined time T3 after the molding cycle stop preparation correction start point C′1, the heating unit is renewed at an appropriate timing without being affected by the time lag of the temperature change of the entire injection apparatus system. It is possible to set a proper heating set temperature.

  For the predetermined time T3, the predetermined time T2 required for the molding cycle stop step is determined in the heating set temperature correction step 2 of the heating barrel temperature control method according to the first embodiment. According to ΔTzx, it suffices to determine how many degrees Celsius the heating set temperature T′zx of each heating means at the molding cycle stop preparation correction start point C′1 is lowered. Therefore, the set value may be changed as appropriate.

  In addition, after completion of the molding cycle, regardless of whether the heating of each heating unit is continued or stopped, at least the setting value of the heating set temperature of each heating unit is automatically set to the initial set temperature Tzx of each heating unit. You may fix it. By this resetting, when the next molding cycle is restarted, it is possible to start the trouble of resetting the heating set temperature of each heating means to the initial set temperature, or the possibility of restarting the operation while forgetting the resetting.

  Furthermore, regarding the coefficient α related to the heating set temperature correction value ΔTzx for one correction, the temperature correction formula 1 in the heating set temperature correction step of the heating barrel temperature control method according to the first embodiment, and the second embodiment, A different α may be set in the temperature correction equation 2 in the heating set temperature correction step of the heating barrel temperature control method. Thereby, more appropriate temperature increase control and temperature decrease control are possible.

  Also in the heating barrel temperature control method 2 of the injection molding machine of the second embodiment, during the molding cycle, the operator of the injection molding machine checks the molded product and initially sets the numerical value according to the situation. Thus, even if the initial heating set temperature Tzx and the target plasticizing resin temperature Tm are changed, the heating setting temperature described above is based on the newly input initial heating setting temperature Tzx and the target plasticizing resin temperature Tm. Needless to say, the correction step 2 is performed.

  The heating barrel temperature control method for an injection molding machine according to the present invention combines the heating set temperature correction step 1 of the first embodiment and the heating temperature correction step 2 of the second embodiment, and the plasticizing state during the continuous molding operation. When the abnormality occurs, temperature correction control (temperature decrease) of the heating set temperature of each heating means of the heating barrel is also possible.

  Specifically, in the heating set temperature correction preparation process of the first embodiment, a tolerance value Q2 is set separately from the tolerance value Q1 described in the preparation process. As described above, the allowable value Q1 is a difference in at least one item of the weighing time, the molded product weight, and the average rotational load factor of the screw for each molding cycle, or the screw 21 in one molding cycle. This relates to the difference in at least one item of the retraction speed and the average rotational load factor of the screw within a minute time, and these are based on the item deeply related to the shear heat energy directly applied to the resin material and the item. It is a result. Therefore, it is an item suitable for grasping the plasticization state of the resin material in the heating barrel 10 with a minimum time lag.

  Therefore, the allowable value Q1 is the start of temperature correction control for raising the temperature of the heating barrel 10 in order to prevent the measurement process from becoming unstable with respect to the heat removal of the heating barrel 10 by the continuously supplied resin material. It is set as the timing (correction start point 1). Similarly, an abnormal state of the plasticized state, which is more problematic than instability of the weighing process, is expected with respect to the difference in at least one item of the weighing time, the weight of the molded product and the average rotational load factor of the screw for each molding cycle. When a difference exceeding the allowable value Q1 is newly set as the allowable amount Q2, the time when the difference of at least one of these items exceeds the allowable value Q2 It can be recognized by the control means of the injection molding machine.

  Although the allowable amount Q2 can be set based on the difference in at least one item of the retraction speed of the screw 21 and the average rotational load factor of the screw within a minute time in one molding cycle, It is difficult to determine the occurrence of an abnormality in the weighing process due to differences in each item over time. If an allowable amount Q2 that is stricter than necessary is set, it is not an abnormality that stops continuous molding operation, or an abnormality is considered. Even when a difference that cannot be made occurs, there is a possibility that the control means of the injection molding machine may recognize that it is abnormal. Therefore, it is preferable to set the allowable amount Q2 based on the difference between each molding cycle or every plural cycles.

  In general, abnormalities in the metering process that require the operation of the injection molding machine to be stopped during continuous molding operations are poor supply of resin material in the supply unit, and resin feed to the compression unit and measurement unit. It is conceivable that the defect deteriorates and the resin material is hardly supplied or the supplied resin material is blocked due to plasticization failure or the like and the resin flow in the resin flow path 14 in the heating barrel 10 stops. .

  In the former case, the rotational torque of the screw 21 decreases and the average rotational load factor also decreases due to the decrease in the resin viscosity accompanying the increase in the resin temperature and the decrease in the amount of resin in the resin flow path 14. In the latter case, even if the resin viscosity decreases as the resin temperature increases, the rotational torque of the screw 21 increases and the average rotational load factor also increases due to the blockage of the resin material in the resin flow path 14. In both cases, of course, the weighing time is long, and there is no doubt that the weight of the molded product will not be stable even if the molding is barely possible. Furthermore, in both cases, the supply of thermal energy to the resin material in the metering process becomes excessive, and the actual temperature of each part of the heating barrel 10 rises.

  When such an abnormality is confirmed, although depending on the degree of abnormality, it is preferable to immediately stop the continuous molding operation from the viewpoint of protecting the apparatus. However, suddenly stopping the heating of each heating means and stopping the continuous molding operation is not preferable in view of a post-processing step due to fixing of the resin material in the heating barrel 10 to the screw 21 or the like. Therefore, the heating set temperature of the heating means of each part of the heating barrel 10 is gradually lowered, and the purge process is started as it is, and the continuous molding operation is stopped as soon as possible from the viewpoint of both the protection of the apparatus and the post-processing process. preferable.

  Therefore, in the heating barrel temperature control method for an injection molding machine according to the third embodiment, during continuous molding operation, at least one item of weighing time, molded product weight, and average screw rotational load factor for each molding cycle. Of the injection molding machine is recognized as the occurrence of an abnormality in the weighing process. By making this point of time recognized by the control means of the injection molding machine in the same manner as the molding cycle stop preparation correction start point C′1 in the second embodiment, the temperature correction formula in the heating setting temperature correction step 1 is changed from the temperature correction formula 1. Switching to the temperature correction formula 2, and based on the heating set temperature correction step 2 in the second embodiment, the heating set temperature T′zx at each time of each heating means is gradually lowered.

  Thus, by setting the allowable value Q2, the abnormal state of the plasticizing state in the heating barrel 10 in the weighing process can be recognized by the control means of the injection molding machine, so that the operator of the injection molding machine Probability can be automatically announced with minimal time lag. Further, as described in the second embodiment, based on the heating set temperature correction step 2, the heating set temperature of each heating means is gradually lowered to avoid an excessive heating state of the heating barrel 10 and the molding cycle Can respond to an emergency stop. As a result, it is possible to protect the injection molding machine as an apparatus and to reduce the load of the post-processing step after the stop.

10 Heating barrel C1 First correction start point 1
C2 Second correction start point 1
C3 3rd correction start point 1
C4 4th correction start point 1
C′1 Molding cycle stop preparation correction start point C′2 Second correction start point 2
C'3 Third correction start point 2
Hn Heating means / part (nozzle part)
H0 heating means / part (reservoir)
H1 Heating means / part (measuring unit)
H2 heating means / part (compression part)
H3 heating means / part (supply part)
T1 predetermined time T2 predetermined time T3 predetermined time

Claims (7)

In the heating barrel temperature control method of an injection molding machine, a plurality of heating means arranged in the longitudinal direction of the heating barrel of the injection device of the injection molding machine are independently controlled.
The target plasticization resin temperature Tm of the resin to be injected and the initial heating set temperature Tzx set in each heating means arranged in the range of the screw supply unit and the compression unit are in the relationship of Tm ≧ Tzx. Heating set temperature correction for setting the heating set temperature correction value ΔTzx for one correction of the heating means using α set in a range of 0.1 ≦ α ≦ 1 by the expression ΔTzx = α (Tm−Tzx) A preparation process;
The first correction start point 1 is a point in time when at least one difference in the weighing time, the molded product weight, and the average rotational load factor of the screw exceeds a preset allowable amount Q1,
The difference is compared with the allowable amount Q1 at a predetermined time T1 set in advance from the first correction start point 1, and the time when the difference exceeds the allowable amount range is determined for the second and subsequent times. The correction start point is 1,
At the correction start point 1 set in advance, the new heating set temperature T′zx is reset by the temperature correction formula 1, T′zx = Tzx + ΔTzx, and each time the next correction start point 1 is reached, The left side of the temperature correction formula 1 is based on the temperature correction formula 1 in which the right side Tzx of the temperature correction formula 1 is replaced with the new heating set temperature T′zx reset at the previous correction start point 1. Heating set temperature correction step 1 for gradually increasing the temperature T'zx of
A heating barrel temperature control method for an injection molding machine.   The comparison between the difference and the allowable amount Q1 performed after the predetermined time T1 set in advance from the first correction start point 1 is performed every molding cycle or every two or more molding cycles. The heating barrel temperature control method of the injection molding machine according to claim 1, which is performed.   The heating set temperature correction step 1 is finished when the new heating set temperature T'zx is in a state satisfying Tm + (Tm-Tzx) ≥T'zx≥Tm. The heating barrel temperature control method of the injection molding machine of any one of Claims 1.   The correction start point 1 in the heating set temperature correction step 1 includes a molding cycle stop preparation correction start point that is a predetermined time T2 before the molding cycle is scheduled to stop, and at the molding cycle stop preparation correction start point, the temperature The correction formula 1 is switched to the temperature correction formula 2, T ″ zx = T′zx−ΔTzx, the new heating set temperature T ″ zx is reset, and the correction start point after the molding cycle stop preparation correction start point 2 further includes a heating set temperature correction step 2 for gradually lowering the new heating set temperature based on the temperature correction formula 2 every time when the predetermined time T3 has passed and the next correction start point 2 is reached. The heating barrel temperature control method of the injection molding machine according to any one of claims 1 to 3.   In the heating set temperature correction step 1, when the difference exceeds a preset allowable amount Q2, the temperature correction formula 1 is switched to the temperature correction formula 2, and the new heating set temperature is gradually lowered. The heating barrel temperature control method of the injection molding machine according to claim 4.   In the heating set temperature correction step 1, based on the initial heating set temperature Tzx or the target plasticizing resin temperature Tm newly changed during the molding cycle, the heating set temperature correction preparation step, the heating set temperature correction step 1 The heating barrel temperature control method for an injection molding machine according to any one of claims 1 to 3, wherein:   In the heating set temperature correction step 2, the heating set temperature correction preparation step, the heating set temperature correction step 1 based on the initial heating set temperature Tzx or the target plasticizing resin temperature Tm newly changed during the molding cycle. Or the heating barrel temperature control method of the injection molding machine of Claim 4 or Claim 5 which performs the said heating preset temperature correction process 2.

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