JP4970165B2 - Clamping force adjustment method - Google Patents

Description

  The present invention relates to a mold clamping force adjustment method in an injection molding machine, and more particularly to a mold clamping force adjustment method in an injection molding machine including a mold clamping unit having a mold clamping load cell for detecting a mold clamping force.

  Synthetic resins can be easily molded and are inexpensive, and are therefore used as materials for various products. In an injection molding machine that molds a product using such a synthetic resin raw material, the raw material pellets are heated and melted, and the molten pellets are fixed and movable molds (hereinafter referred to as “molds”). After injection into the cavity, solidify. Then, the product solidified by opening the mold is taken out and the product is manufactured.

  The above-described injection molding machine can be broadly classified to open and close the mold by advancing and retracting the movable die plate by an injection unit that melts the raw material pellets and then injects it into the mold cavity and the mold clamping drive means. A mold clamping unit and a control unit for controlling the whole are provided. In the mold clamping unit, moving to the injection unit side is referred to as “forward”, and moving in the opposite direction is referred to as “backward”.

  Recently, there is also an injection molding machine including a mold temperature adjustment unit that adjusts the temperature of a mold as disclosed in Patent Document 1. By maintaining the temperature of the mold within a predetermined range by this mold temperature adjusting unit, the molding quality can be kept constant.

  Now, the force which clamps a metal mold | die at the time of shaping | molding (it is called mold clamping force) changes for every metal mold | die. For this reason, when the mold is replaced, it is necessary to adjust the clamping force to a predetermined value before performing continuous molding. Usually, as disclosed in Patent Document 2, the generated mold clamping force is adjusted by moving the tailstock.

  The process for adjusting the mold clamping force will be described with reference to FIG. This process consists of two steps. In the first tailstock position adjusting step (step S940), the position where the movable mold just contacts the fixed mold when the movable die plate is advanced to the position farthest from the tailstock by the mold clamping drive means. Move the tailstock to.

  In the subsequent second tail stock position adjusting step (step S960), the tail stock is advanced to a position where a predetermined mold clamping force can be generated. By adjusting the position of the tail stock in this way, a predetermined mold clamping force can be generated when the movable die plate is advanced to the position farthest from the tail stock by the mold clamping driving means. In other words, the second tailstock position adjusting step is a step of finally adjusting the mold clamping force that can be generated by the mold clamping unit. As a method for adjusting the position of the tailstock, a method using a ring gear is widely known (see, for example, Patent Documents 3 and 4).

  A technique for detecting this clamping force with higher accuracy has also been proposed. For example, Patent Document 5 discloses a technique for detecting a mold clamping force using a mold clamping load cell provided close to a mold. According to this technique, since the mold clamping force can be directly detected, the mold clamping force can be detected with high accuracy.

  However, the zero point of the clamping load cell shifts due to temperature and aging. When the zero point is shifted, an error occurs in the value of the detected clamping force. Due to this error, the mold clamping force varies, and a “molding defect” may occur in which continuous molding with the same shape cannot be performed. Further, abnormal mold clamping force may be generated, and the device (mold or injection molding machine itself) may be damaged. For this reason, the operator needs to correct the zero point before adjusting the mold clamping force so that the mold clamping load cell can accurately detect the mold clamping force.

JP-A 63-56410 Japanese Patent Publication No. 7-45100 JP-A-7-68610 Japanese Patent Laid-Open No. 2003-231161 Japanese Patent No. 3749783

  According to the background art described above, it is necessary to correct the zero point of the mold clamping load cell and adjust the mold clamping force before continuous molding. Normally, the molding process itself cannot be executed unless the mold clamping force is adjusted. Therefore, the operator always adjusts the mold clamping force when changing the mold. On the other hand, the molding itself can be performed without correcting the zero point of the mold clamping load cell. For this reason, the zero point correction of the mold clamping load cell is often not performed before continuous molding.

  Even when the zero point correction of the mold clamping load cell is performed, the zero point correction may be performed in a state where the mold temperature is not stable. The output value of the mold clamping load cell is greatly influenced by the temperature of the mold and the temperature of the mold clamping load cell itself close to the mold, so accurate zero point correction cannot be performed when the temperature is not stable. .

  In these cases, since the mold clamping force adjustment is executed in a state where the zero point of the mold clamping load cell is shifted, the generated mold clamping force is adjusted to a value shifted from a predetermined value. If continuous molding is executed in a state where the mold clamping force is deviated from a predetermined value, molding defects may occur or the apparatus may be damaged.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a mold clamping force adjustment method that reliably executes a zero point correction of a mold clamping load cell.

  The mold clamping force adjusting method according to claim 1 includes a fixed die plate to which a fixed mold is attached, a movable die plate to which a movable mold that is opened and closed with the fixed mold is mounted, and the movable die plate that is used to open and close the mold. Mold clamping driving means for generating a driving force for advancing and retreating, a tail stock attached with the mold clamping driving means, a tie bar connecting the fixed die plate and the tail stock, and a tail for moving the tail stock forward and backward along the tie bar Injection including a stock moving means, a clamping unit having a clamping load cell for detecting clamping force, an injection unit for melting and injecting pellets, and a control unit for controlling the clamping unit and the injection unit In the molding machine, the mold clamping drive means is driven to move the moving die plate farthest from the tailstock. A first tailstock position adjusting step of moving the tailstock by driving the tailstock moving means to a position where the movable mold comes into contact with the fixed mold when advanced to a position; and the tailstock And a second tailstock position adjusting step of moving the tailstock to a position where a predetermined mold clamping force can be generated by driving a moving means, wherein the second tailstock is adjusted. The method further comprises a zero point correcting step of automatically correcting the zero point of the clamping load cell before the position adjusting step is executed.

  According to the mold clamping force adjusting method according to claim 1, the zero point of the mold clamping load cell is automatically set before the second tailstock position adjusting step is executed even if the operator does not operate. Will be corrected.

  The mold clamping force adjusting method according to claim 2, wherein a fixed die plate for attaching a fixed die, a movable die plate for attaching a movable die that is opened and closed with the fixed die, and the movable die plate for opening and closing the die are provided. Mold clamping driving means for generating a driving force for advancing and retreating, a tail stock attached with the mold clamping driving means, a tie bar connecting the fixed die plate and the tail stock, and a tail for moving the tail stock forward and backward along the tie bar Stock moving means, mold clamping unit having a mold clamping load cell for detecting mold clamping force, injection unit for melting and injecting pellets, mold temperature adjustment for adjusting the temperature of the fixed mold and the movable mold And a control unit for controlling the mold clamping unit and the injection unit and monitoring the mold temperature adjustment unit In the injection molding machine having the above, when the movable die plate is advanced to the position farthest from the tailstock by driving the mold clamping driving means, the movable mold comes into a position where it comes into contact with the fixed mold. A first tail stock position adjusting step for driving the tail stock moving means to move the tail stock; and driving the tail stock moving means to move the tail stock to a position where a predetermined mold clamping force can be generated. A mold clamping force adjustment method comprising: a second tailstock position adjustment step for moving; a determination step for determining whether or not the temperatures of the fixed mold and the movable mold are stable; and the determination When it is determined that the temperature is stable in the process, the zero point of the mold clamping load cell is automatically set before the second tailstock position adjusting process is executed. Further characterized in that a zero point correcting step of correcting.

  According to the mold clamping force adjusting method of the second aspect, when it is determined that the temperature of the mold is stable, the operator performs the operation before the second tailstock position adjusting process is executed. Even without operation, the zero point of the mold clamping load cell is automatically corrected.

  The mold clamping force adjusting method according to a third aspect of the present invention is the method according to the second aspect, wherein the determination step is performed after the temperature of the fixed mold and the movable mold enters a stable range of a set value during continuous molding. Only when the time has passed and the temperature of the fixed mold and the movable mold is within the stable range of the set value during the continuous molding, the temperature of the fixed mold and the movable mold is It is judged to be stable.

  According to the mold clamping force adjusting method according to claim 3, a predetermined time has elapsed since the mold temperature has entered the stable range of the set value at the time of continuous molding, and the mold temperature is continuous even at the present time. Only when it is within the stable range of the set value at the time of molding, it is determined that the mold temperature is stable. Here, the stable range of the set value is a range in which it is determined that the temperature has converged to the set value in consideration of a control error such as a deviation from the set value and jitter. For example, even if the set value is set to 90 ° C., it is not always 90 ° C. due to a control error. In this case, if the range for determining that the control error is absorbed and converged is ± 2 ° C., the stable range of the set value is “88 ° C. or more and 92 ° C. or less”.

  The mold clamping force adjusting method according to claim 4 is the method according to claim 2 or 3, wherein, in the determination step, the temperature of the fixed mold and the movable mold is not determined to be stable. The zero point correcting step, the first tail stock position adjusting step, and the second tail stock position adjusting step are not executed.

  According to the mold clamping force adjusting method of the fourth aspect, the mold clamping force adjustment is not executed when the temperature of the mold is not stable.

  A mold clamping force adjusting method according to a fifth aspect of the present invention is the method according to any one of the first to fourth aspects, wherein the zero point correcting step is performed when the mold clamping driving means does not generate a driving force. A value output from the load cell is set as a zero point.

  According to the mold clamping force adjusting method of the fifth aspect, the zero point correction of the mold clamping load cell is executed in a state where the mold clamping driving means does not generate a driving force, that is, in a state where the mold clamping force is zero. The

  According to the present invention, since the zero point of the mold clamping load cell is automatically corrected before the second tailstock position adjusting process is performed without the operator's operation, the operator can Even if you forget to execute the zero correction of the load cell, the zero correction is always performed. Therefore, the second tailstock position adjustment process (that is, the final adjustment process of the mold clamping force) is executed after the zero point correction of the mold clamping load cell, so that the adjustment accuracy of the mold clamping force can be improved. In addition, it is possible to reduce the frequency of occurrence of molding defects and the frequency of breakage of the apparatus.

  Further, according to the present invention, when it is determined that the temperature of the mold is stable, the automatic operation can be performed without an operator's operation before the second tailstock position adjusting step is executed. Therefore, even if the operator forgets to perform the zero correction of the mold clamping load cell, if it is determined that the mold temperature is stable, the zero point of the mold clamping load cell is corrected. Corrections are always made. Accordingly, the second tailstock position adjusting process (ie, the final adjusting process of the mold clamping force) is executed after correcting the zero point of the mold clamping load cell while the mold temperature is stable. The force adjustment accuracy can be further improved, and the occurrence frequency of molding defects and the frequency of breakage of the apparatus can be further reduced.

  Furthermore, according to the present invention, a predetermined time has elapsed since the mold temperature entered the stable range of the set value during continuous molding, and the mold temperature is still stable at the present time during continuous molding. Only when it is within the range, it is determined that the temperature of the mold is stable, so that the mold clamping force adjustment is performed in a temperature state that is close and stable during continuous molding. Therefore, the adjustment accuracy of the mold clamping force can be further improved, and the frequency of occurrence of molding failure and the frequency of breakage of the apparatus can be further reduced. In addition, because the mold clamping force adjustment is performed before continuous molding, not during continuous molding, it is not necessary to temporarily stop continuous molding for mold clamping force adjustment during continuous molding. Can be improved.

  Further, according to the present invention, when the mold temperature is not stable, the mold clamping force adjustment is not executed, so that the mold temperature is not stable, that is, the output value of the mold clamping load cell is It is possible to prevent the mold clamping force from being adjusted. Therefore, in an injection molding machine that cannot perform continuous molding unless the mold clamping force adjustment is performed, continuous molding with poor mold clamping force adjustment accuracy can be prevented, thus preventing molding defects and equipment damage. Can do.

  Furthermore, according to the present invention, since the zero point correction of the mold clamping load cell is executed in a state where no mold clamping force is generated, the zero point correction can be performed very easily.

  Embodiments of the present invention will be described with reference to the drawings. The following examples are only specific examples of the present invention, and the present invention is not limited to the following embodiments.

  FIG. 1 is a cross-sectional view showing an injection molding machine according to the present embodiment. The injection molding machine 1 is roughly divided into a mold clamping unit 2, an injection unit 3, and a control unit 4. Since the injection unit 3 is generally used and is a known technique, the description thereof is omitted.

  In the mold clamping unit 2, the mold 11 is clamped by the mold clamping drive means 30. The mold 11 includes a fixed mold 11a and a movable mold 11b. The fixed mold 11 a is mounted on the fixed die plate 12, and the movable mold 11 b is mounted on the moving die plate 13. A housing 15 is attached to the back surface (left side in FIG. 1) of the movable die plate 13 via a mold clamping load cell 17. The mold clamping load cell 17 can detect the mold clamping force applied to the mold 11.

  A tie bar 14 is installed between the fixed die plate 12 and the tail stock 16, and the movable die plate 13 is slidably attached to the tie bar 14.

  A mold control servo motor 31 is attached to the tail stock 16. A drive pulley 33 attached to the rotational drive shaft of the tail stock 16 and a toggle drive nut 36 rotatably arranged on the tail stock 16 via a bearing are provided. A driven pulley 34 fixed to the protruding end is connected via a timing belt 35.

  A toggle drive screw 41 is screwed to the driven pulley 34 via a toggle drive nut 36 so that the toggle drive screw 41 can move forward and backward. A protruding end of the toggle drive screw 41 is attached to the cross head 42. The toggle link mechanism 40 has long and short arms 43 connected to the link mechanism, one end of which is pivotally connected to the tailstock 16, the other end is pivotally connected to the housing 15, and another end. The part is attached to the crosshead 42.

  The mold 11 is clamped as follows. That is, the mold control servo motor 31 is operated, and the rotational force is transmitted to the driven pulley 34 via the drive pulley 33 and the transmission belt 35. Then, the driven pulley 34 drives the toggle drive screw 41 via the toggle drive nut 36, and the toggle drive screw 41 advances to the right in FIG. 1 to advance the crosshead 42 and extend the toggle link mechanism 40.

  At this time, the movable die plate 13 and the movable mold 11b mounted on the movable die plate 13 move to the fixed mold 11a side in accordance with the extension, and the movable mold 11b is pressed against the fixed mold 11a with a predetermined pressure. Tightening is done. The position of the moving die plate 13 can be detected by using an encoder 32 attached to the mold control servomotor 31. The mold control servomotor 31, drive pulley 33, timing belt 35, driven pulley 34, toggle drive nut 36, toggle drive screw 41, crosshead 42, long and short arms 43, and encoder 32 are used in the above configuration. The mold clamping driving means 30 is generated that generates a driving force for moving the movable die plate 13 back and forth for opening and closing.

  However, since the clamping force varies depending on the molded product (that is, varies depending on the mold), the value must be changeable. In this embodiment, the mold clamping force that can be generated is changed by changing the position of the tailstock 16. A servo motor 21 is attached to the tail stock 16 and rotates the ring gear 23. By the rotation of the ring gear 23, all the adjustment nuts 24 screwed into all the tie bars 14 are rotated, and the tail stock 16 is moved forward and backward by moving forward and backward in the longitudinal direction of the tie bars 14. The position of the tail stock 16 can be detected by an encoder 22 attached to the servo motor 21. The tail stock moving means 20 for moving the tail stock 16 forward and backward along the tie bar 14 is realized by the above configuration, that is, the servo motor 21, the ring gear 23, the adjustment nut 24, and the encoder 22.

  The control unit 4 controls the mold clamping unit 2 and the injection unit 3. The control unit 4 includes a control unit 61 that actually performs control and an input / output unit 62 that performs input and output with an operator. The control means 61 controls each part based on signals from the mold clamping load cell 17, the encoder 32, and the like. Since all control of the drive system is performed by a servo motor, it is possible to create arbitrary conditions such as complex operation by a program. At this time, the input / output means 62 (for example, a display with a touch panel) can be used to input and confirm conditions.

  Next, the flow of processing of the mold clamping force adjustment method of the present embodiment will be described with reference to FIGS. 3, 7, and 8. FIG. 3 is a flowchart showing a main routine of the mold clamping force adjusting method of this embodiment. This flowchart is started when a mold clamping force adjustment instruction is given. Note that each process in the flowchart is controlled by the control unit 4.

  In step S140, the control unit 4 executes a first tailstock position adjustment step (described later), and proceeds to step S150.

  In step S150, the control unit 4 corrects the zero point of the mold clamping load cell 17, and proceeds to step S160. Specifically, the output value of the mold clamping load cell 17 when the mold 11 is open and the mold clamping force is not applied is defined as a zero point.

  In step S160, the control unit 4 executes a second tailstock position adjustment process (described later), and ends the main routine.

  FIG. 7 is a flowchart showing a first tailstock position adjusting process of the present embodiment. All processes in this flowchart are controlled by the control unit 4.

  In step S510, the control unit 4 drives the mold control servo motor 31 to retract the movable die plate 13 to the position closest to the tail stock 16, and proceeds to step S520. Here, the position of the movable die plate 13 can be detected by the encoder 32.

  In step S520, the control unit 4 drives the servo motor 21 to retract the tail stock 16 by a predetermined amount (for example, 10 mm), and proceeds to step S530. Here, the position and amount of movement of the tailstock 16 can be detected by the encoder 22.

  In step S530, the control unit 4 drives the mold control servo motor 31 to advance the moving die plate 13, and proceeds to step S540.

  In step S540, the control unit 4 determines whether or not the movable mold 11b is in contact with the fixed mold 11a. If so, the process proceeds to step S510, and if not, the process proceeds to step S550.

  In step S550, the control unit 4 determines whether or not the moving die plate 13 has advanced to the position farthest away from the tailstock 16, and if it has advanced to the position farthest away, the process proceeds to step S560. Otherwise, the process proceeds to step S530.

  In step S560, the control unit 4 drives the servo motor 21, advances the tail stock 16, and proceeds to step S570.

  In step S570, the control unit 4 determines whether or not the movable mold 11b is in contact with the fixed mold 11a. If so, the process proceeds to step S580, and if not, the process proceeds to step S560.

  In step S580, the control unit 4 drives the mold control servo motor 31 to retract the movable die plate 13 to a position closest to the tail stock 16, and ends the first tail stock position adjusting process.

  When the process of the flowchart shown in FIG. 7 (first tailstock position adjusting step) is executed, the tailstock 16 drives the mold control servo motor 31 to move the movable die plate 13 farthest from the tailstock 16. Is moved to a position where the movable mold 11b can be brought into contact with the fixed mold 11a.

  FIG. 8 is a flowchart showing a second tailstock position adjusting process of the present embodiment. All processes in this flowchart are controlled by the control unit 4.

  In step S610, the control unit 4 calculates the extension amount of the tie bar 14 for generating a predetermined mold clamping force, and proceeds to step S620.

  In step S620, the control unit 4 drives the servo motor 21 to advance the tail stock 16 by the amount of elongation calculated in step S610, and proceeds to step S630.

  In step S630, the control unit 4 detects the mold clamping force using the mold clamping load cell 17, and proceeds to step S640.

  In step S640, the control unit 4 determines whether or not the mold clamping force detected in step S630 is a predetermined value. If it is the predetermined value, the control unit 4 ends the second tailstock position adjusting process. If not, the process proceeds to step S650.

  In step S650, the control unit 4 corrects the position of the tailstock 16, and proceeds to step S630.

  When the process of the flowchart shown in FIG. 8 (second tailstock position adjusting step) is executed, the tailstock 16 moves to a position where a predetermined mold clamping force can be generated during mold clamping. That is, the mold clamping force that can be generated by the mold clamping unit 2 can be adjusted.

  As described above, the zero point correction and the mold clamping force adjustment of the mold clamping load cell 17 are performed by executing the processing of this embodiment. That is, in the mold clamping force adjustment process, the zero point correction of the mold clamping load cell 17 is always executed.

  FIG. 2 is a cross-sectional view showing the injection molding machine according to the present embodiment. The injection molding machine 1 is roughly divided into a mold clamping unit 2, an injection unit 3, a mold temperature adjustment unit 5, and a control unit 4. Since the injection unit 3 is generally used and is a known technique, the description thereof is omitted. Moreover, about the mold clamping unit 2, since the part which attached | subjected the code | symbol same as each part of the mold clamping unit of Example 1 has the same function, and the same operation | movement, description is abbreviate | omitted.

  The mold temperature adjustment unit 5 includes a pipe 72 and a temperature control means 71. The pipe 72 is a flow path for circulating the medium between the mold 11 and the temperature control means 71. The temperature control means 71 includes a pump for circulating the medium, a temperature adjusting device for heating / cooling the medium, a temperature sensor for detecting the temperature of the medium, and a microprocessor for controlling them. Using the mold temperature adjustment unit 5 having such a configuration, the temperature of the mold 11 can be adjusted to a predetermined set value (for example, 90 ° C.).

  The control unit 4 controls the mold clamping unit 2 and the injection unit 3 and monitors the mold temperature adjustment unit 5. The control unit 4 includes a control unit 61 that actually performs control and an input / output unit 62 that performs input and output with an operator. The control means 61 controls each part based on signals from the mold clamping load cell 17, the encoder 32, and the like. Moreover, it communicates with the temperature control means 71 and acquires information regarding the temperature of the mold. Since all control of the drive system is performed by a servo motor, it is possible to create arbitrary conditions such as complex operation by a program. At this time, the input / output means 62 (for example, a display with a touch panel) can be used to input and confirm conditions.

  Next, the processing flow of the mold clamping force adjusting method of the present embodiment will be described with reference to FIGS. FIG. 4 is a flowchart showing a main routine of the mold clamping force adjusting method of this embodiment. This flowchart is started when a mold clamping force adjustment instruction is given. Note that each process in the flowchart is controlled by the control unit 4.

  In step S210, the control unit 4 executes a mold temperature state acquisition step (described later), and proceeds to step S220.

  In step S220, the control unit 4 determines whether or not the mold temperature state is “stable”. If it is “stable”, the process proceeds to step S240; otherwise, the process proceeds to step S230.

  In step S230, the control unit 4 displays an alarm using the input / output means 62 and ends the main routine.

  In step S240, the control unit 4 executes the first tailstock position adjustment process, and proceeds to step S250. Here, the first tailstock position adjusting step is the same as that in the first embodiment, and thus the description thereof is omitted.

  In step S250, the control unit 4 corrects the zero point of the mold clamping load cell 17, and proceeds to step S260. Specifically, the output value of the mold clamping load cell 17 when the mold 11 is open and the mold clamping force is not applied is defined as a zero point.

  In step S260, the control unit 4 executes the second tailstock position adjustment process and ends the main routine. Here, the second tailstock position adjusting step is the same as that in the first embodiment, and thus the description thereof is omitted.

  FIG. 9 is a flowchart showing the mold temperature state acquisition process of the present embodiment. All processes in this flowchart are controlled by the control unit 4.

  In step S710, the control unit 4 determines whether a predetermined time (for example, 15 minutes) has elapsed since the mold temperature has entered the stable range of the set value during continuous molding (for example, 88 ° C. or more and 92 ° C. or less). Information indicating whether or not is acquired from the temperature control means 71 of the mold temperature adjustment unit 5, and if the predetermined time has elapsed, the process proceeds to step S720, and if not, the process proceeds to step S740.

  In step S720, the control unit 4 adjusts the mold temperature information indicating whether the mold temperature is currently within a stable range of set values during continuous molding (for example, 88 ° C. or more and 92 ° C. or less). If it is acquired from the temperature control means 71 of the unit 5 and entered, the process proceeds to step S730, and if not, the process proceeds to step S740.

  In step S730, the control unit 4 stores the mold temperature state as “stable” and ends the mold temperature state acquisition step.

  In step S740, the control unit 4 stores the mold temperature state as “unstable” and ends the mold temperature state acquisition step.

  When the process of the flowchart shown in FIG. 9 (mold temperature state acquisition step) is executed, the control unit 4 can acquire information indicating whether the mold temperature state is “stable”. Therefore, in the above-described step S220, it can be determined whether or not the mold temperature state is “stable”.

  As described above, by executing the processing of the present embodiment, the zero point correction and the mold clamping force adjustment of the mold clamping load cell 17 are performed while the mold temperature is stable. That is, in the mold clamping force adjustment process, the zero point correction of the mold clamping load cell 17 is always executed in a state where the mold temperature is stable.

  Since the injection molding machine according to the present embodiment is the same as that of the first embodiment, description thereof is omitted. FIG. 5 is a flowchart showing a main routine of the mold clamping force adjusting method of this embodiment. This flowchart is started when a mold clamping force adjustment instruction is given. Note that each process in the flowchart is controlled by the control unit 4.

  In step S350, the control unit 4 corrects the zero point of the mold clamping load cell 17, and proceeds to step S340. Specifically, after the mold 11 is opened and the mold clamping force is not applied, the output value of the mold clamping load cell 17 is set to the zero point.

  In step S340, the control unit 4 executes the first tailstock position adjustment process, and proceeds to step S360. Here, the first tailstock position adjusting step is the same as that in the first embodiment, and thus the description thereof is omitted.

  In step S360, the control unit 4 executes the second tailstock position adjustment process and ends the main routine. Here, the second tailstock position adjusting step is the same as that in the first embodiment, and thus the description thereof is omitted.

  As described above, the zero point correction and the mold clamping force adjustment of the mold clamping load cell 17 are performed by executing the processing of this embodiment. That is, in the mold clamping force adjustment process, the zero point correction of the mold clamping load cell 17 is always executed.

  Since the injection molding machine according to the present embodiment is the same as that of the second embodiment, description thereof is omitted. FIG. 6 is a flowchart showing a main routine of the mold clamping force adjusting method of this embodiment. This flowchart is started when a mold clamping force adjustment instruction is given. Note that each process in the flowchart is controlled by the control unit 4.

  In step S410, the control unit 4 executes a mold temperature state acquisition process, and proceeds to step S420. Here, the mold temperature state acquisition step is the same as in the case of the second embodiment, and a description thereof will be omitted.

  In step S420, the control unit 4 determines whether or not the mold temperature state is “stable”. If it is “stable”, the process proceeds to step S450, and if not, the process proceeds to step S430.

  In step S430, the control unit 4 displays an alarm using the input / output means 62 and ends the main routine.

  In step S450, the control unit 4 corrects the zero point of the mold clamping load cell, and proceeds to step S440. Specifically, after the mold 11 is opened and the mold clamping force is not applied, the output value of the mold clamping load cell 17 is set to the zero point.

  In step S440, the control unit 4 executes the first tailstock position adjustment process, and proceeds to step S460. Here, the first tailstock position adjusting step is the same as that in the first embodiment, and thus the description thereof is omitted.

  In step S460, the control unit 4 executes the second tailstock position adjustment process and ends the main routine. Here, the second tailstock position adjusting step is the same as that in the first embodiment, and thus the description thereof is omitted.

  As described above, by executing the processing of the present embodiment, the zero point correction and the mold clamping force adjustment of the mold clamping load cell 17 are performed while the mold temperature is stable. That is, in the mold clamping force adjustment process, the zero point correction of the mold clamping load cell 17 is always executed in a state where the mold temperature is stable.

  In summary, according to the present invention, it is possible to provide a mold clamping force adjustment method that reliably corrects the zero point of the mold clamping load cell.

  Note that the contact of the movable mold 11b with the fixed mold 11a can be detected using, for example, the mold clamping load cell 17. Specifically, it is only necessary that the contact is made when the output value of the mold clamping load cell 17 changes abruptly (in the case of this method, it is only necessary to detect “change” of the output value. Even if it exists, the contact of the mold 11 can be detected.)

It is sectional drawing which shows the injection molding machine which concerns on Example 1 and 3 of this invention. It is sectional drawing which shows the injection molding machine which concerns on Example 2 and 4 of this invention. It is a flowchart which shows the flow of a process of Example 1 of this invention. It is a flowchart which shows the flow of a process of Example 2 of this invention. It is a flowchart which shows the flow of a process of Example 3 of this invention. It is a flowchart which shows the flow of a process of Example 4 of this invention. It is a flowchart which shows the flow of a process of the 1st tail stock position adjustment process which concerns on Example 1, 2, 3 and 4 of this invention. It is a flowchart which shows the flow of a process of the 2nd tail stock position adjustment process which concerns on Example 1, 2, 3 and 4 of this invention. It is a flowchart which shows the flow of a process of the metal mold | die temperature state acquisition process which concerns on Example 2 and 4 of this invention. It is a flowchart which shows the flow of a process of the conventional mold clamping force adjustment method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection molding machine 2 Mold clamping unit 3 Injection unit 4 Control unit 5 Mold temperature control unit 11a Fixed mold 11b Movable mold 12 Fixed die plate 13 Moving die plate 14 Tie bar 16 Tail stock 17 Mold clamping load cell 20 Tail stock moving means 30 Mold clamping drive means

Claims (5)

A fixed die plate for attaching a fixed die, a movable die plate for attaching a movable die that is opened and closed with the fixed die, and a mold clamping driving means for generating a driving force for moving the movable die plate forward and backward for opening and closing the die A tail stock to which the mold clamping driving means is attached, a tie bar for connecting the fixed die plate and the tail stock, a tail stock moving means for moving the tail stock back and forth along the tie bar, and a mold clamping for detecting a mold clamping force. A clamping unit having a load cell;
An injection unit for melting and injecting pellets;
In an injection molding machine comprising the mold clamping unit and a control unit for controlling the injection unit,
When the mold clamping driving means is driven to advance the movable die plate to a position farthest from the tailstock, the tailstock moving means is driven to a position where the movable mold comes into contact with the fixed mold. A first tailstock position adjusting step of moving the tailstock;
A mold clamping force adjustment method comprising: a second tailstock position adjusting step of driving the tailstock moving means to move the tailstock to a position where a predetermined mold clamping force can be generated,
A mold clamping force adjusting method, further comprising a zero point correcting step of automatically correcting the zero point of the mold clamping load cell before the second tailstock position adjusting step is executed. A fixed die plate for attaching a fixed die, a movable die plate for attaching a movable die that is opened and closed with the fixed die, and a mold clamping driving means for generating a driving force for moving the movable die plate forward and backward for opening and closing the die A tail stock to which the mold clamping driving means is attached, a tie bar for connecting the fixed die plate and the tail stock, a tail stock moving means for moving the tail stock back and forth along the tie bar, and a mold clamping for detecting a mold clamping force. A clamping unit having a load cell;
An injection unit for melting and injecting pellets;
A mold temperature adjustment unit for adjusting the temperature of the fixed mold and the movable mold;
In an injection molding machine comprising a control unit for controlling the mold clamping unit and the injection unit and monitoring the mold temperature adjustment unit,
When the mold clamping driving means is driven to advance the movable die plate to a position farthest from the tailstock, the tailstock moving means is driven to a position where the movable mold comes into contact with the fixed mold. A first tailstock position adjusting step of moving the tailstock;
A mold clamping force adjustment method comprising: a second tailstock position adjusting step of driving the tailstock moving means to move the tailstock to a position where a predetermined mold clamping force can be generated,
A determination step of determining whether the temperature of the fixed mold and the movable mold is stable;
Zero point correction that automatically corrects the zero point of the clamping load cell before the second tailstock position adjustment step is executed when it is determined that the temperature is stable in the determination step A mold clamping force adjusting method, further comprising: a step.   In the determining step, a predetermined time has elapsed since the temperatures of the fixed mold and the movable mold are within a stable range of set values during continuous molding, and the fixed mold and the movable mold The temperature of the fixed mold and the movable mold is determined to be stable only when the temperature is within a stable range of the set value at the time of the continuous molding. Mold clamping force adjustment method.   In the determination step, when it is not determined that the temperatures of the stationary mold and the movable mold are stable, the zero point correction step, the first tailstock position adjustment step, and the second 4. The mold clamping force adjusting method according to claim 2, wherein the tail stock position adjusting step is not executed.   5. The zero point correcting step uses the value output from the mold clamping load cell in a state where the mold clamping driving means does not generate a driving force as a zero point. 6. Clamping force adjustment method described in 1.

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