Control device and control method of injection molding machine

By calculating the suck-back distance or time through the injection molding machine's control device, the operator's difficulty in properly determining the suck-back problem is solved, thereby improving the quality of molded products and production efficiency.

CN112917854BActive Publication Date: 2025-09-16FANUC LTD
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Patent Information

Application Number
CN202011409982.1
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Priority Date
2019-12-06
Filing Date
2020-12-04
Publication Date
2025-09-16
Estimated Expiration
2040-12-04

AI Technical Summary

Technical Problem

In injection molding machines, operators need to use trial and error to appropriately determine the suction distance and suction time to prevent resin leakage, which leads to operational burdens and makes it difficult to ensure the quality of molded products.

Method used

A control device is used to calculate the target volume of the resin in the nozzle, and the screw's back suction is controlled by calculating the back suction distance or back suction time to ensure that the resin is introduced into the cylinder at the target volume, reducing casting and mixing of foreign matter.

Benefits of technology

The appropriate and simple determination of the re-sucking distance or re-sucking time is achieved, which reduces the possibility of casting and mixing of foreign matter, and improves the quality of molded products and production efficiency.

✦ Generated by Eureka AI based on patent content.

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Abstract

The present invention provides a control device and a control method for an injection molding machine. The injection molding machine (10) comprises a cylinder (26) for placing resin, a nozzle (40) provided at the front end of the cylinder (26), and a screw (28) that moves forward and backward in the cylinder (26). The screw is retracted to a measuring position while maintaining a measuring pressure (P1), thereby melting the resin in the cylinder (26) and measuring the resin at the same time. The control device (20) comprises: a calculation unit (80) for calculating the target volume (V) of the resin in the nozzle (40). tar ) The suction distance (L) introduced to the cylinder (26) side sb ) or back suction time (T sb ); and a back-suction control unit (84), which, after the screw (28) reaches the measuring position, is based on the back-suction distance (L sb ) or back suction time (T sb ) causes the screw (28) to be sucked back.
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Claims

1. A control device for an injection molding machine, comprising: a cylinder for placing resin; a nozzle provided at a front end of the cylinder; and a screw that moves forward, backward, and rotates within the cylinder, wherein the screw is moved backward to a predetermined measurement position while rotating forward while maintaining a predetermined measurement pressure, thereby melting the resin within the cylinder and performing measurement simultaneously. It is characterized in that The control device comprises: a calculation unit that calculates a suction distance or a suction time for achieving introduction of the resin in the nozzle to the cylinder side at the target volume based on a target volume of the resin in the nozzle to be introduced from the nozzle side to the cylinder side; as well as a back-suction control unit configured to cause the screw to back-suction based on the back-suction distance or the back-suction time after the screw reaches the predetermined measurement position; The calculation section calculates the target volume based on a shape of the nozzle and a target distance of the resin introduced into the nozzle from the nozzle side to the cylinder side.

2. The control device for an injection molding machine according to claim 1, wherein: The control device further includes a volume change acquisition unit that acquires a volume change of the resin measured in the cylinder during a period of reducing pressure from the predetermined measurement pressure to atmospheric pressure after the screw reaches the predetermined measurement position. The calculation unit calculates the back-suction distance or the back-suction time based on the change amount and the target volume.

3. The control device for an injection molding machine according to claim 2, wherein: The control device further includes a pressure acquisition unit that acquires the pressure of the resin. The volume change acquisition unit acquires the amount of change based on a distance the screw retreats during measurement and a pressure of the resin when the screw reaches the predetermined measurement position.

4. The control device for an injection molding machine according to claim 2, wherein: The control device further includes a storage unit storing a table in which the amount of change and the type of resin are associated with each other. The volume change acquisition unit acquires the amount of change based on the type of the resin by referring to the table.

5. The control device for an injection molding machine according to any one of claims 1 to 4, wherein: The control device further includes an operation unit for an operator to designate the target volume.

6. The control device for an injection molding machine according to claim 1, wherein: The control device further includes a storage unit storing a first table, wherein a plurality of functions are defined corresponding to the shape of the nozzle, and the functions are used to calculate the target volume based on the shape of the nozzle and the target distance. The calculation unit selects the function corresponding to the shape of the nozzle provided in the cylinder from the first table, and calculates the back-suction distance or the back-suction time based on the selected function and the target distance.

7. The control device for an injection molding machine according to claim 6, wherein: The control device further includes a volume change acquisition unit that acquires a volume change of the resin measured in the cylinder during a period of reducing pressure from the predetermined measurement pressure to atmospheric pressure after the screw reaches the predetermined measurement position. The calculation unit calculates the back-suction distance or the back-suction time based on the change amount and the target volume.

8. The control device for an injection molding machine according to claim 7, wherein: The control device further includes a pressure acquisition unit that acquires the pressure of the resin. The volume change acquisition unit acquires the amount of change based on a distance the screw retreats during measurement and a pressure of the resin when the screw reaches the predetermined measurement position.

9. The control device for an injection molding machine according to claim 7, wherein: The storage unit further stores a second table in which the variation and the type of the resin are associated with each other. The volume change acquisition unit acquires the amount of change based on the type of the resin by referring to the second table.

10. The control device for an injection molding machine according to any one of claims 6 to 9, wherein: The control device further includes an operation unit for an operator to indicate the target distance.

11. The control device for an injection molding machine according to any one of claims 1 to 4 and 6 to 9, characterized in that: When the target volume exceeds a predetermined limit value, the calculation unit calculates the back-suction distance or the back-suction time after limiting the target volume to be equal to or less than the limit value.

12. The control device for an injection molding machine according to any one of claims 1 to 4 and 6 to 9, characterized in that: The calculation unit includes a correction unit that corrects the calculated back-inhalation distance or the back-inhalation time to the upper limit value when the calculated back-inhalation distance or the back-inhalation time exceeds a predetermined upper limit value.

13. The control device for an injection molding machine according to any one of claims 1 to 4 and 6 to 9, characterized in that: The control device further includes a notification unit configured to notify the calculated back-suction distance or the back-suction time.

14. A method for controlling an injection molding machine, the injection molding machine comprising: a cylinder for placing resin; a nozzle provided at a front end of the cylinder; and a screw that moves forward, backward, and rotates within the cylinder, wherein the screw is retracted to a predetermined measurement position while rotating forward while maintaining a predetermined measurement pressure, thereby performing measurement while melting the resin within the cylinder. It is characterized in that The control method comprises the following steps: a calculating step of calculating a target volume of the resin in the nozzle to be introduced from the nozzle side to the cylinder side based on a shape of the nozzle and a target distance of the resin in the nozzle to be introduced from the nozzle side to the cylinder side, and calculating a back-suction distance or a back-suction time for achieving introduction of the resin in the nozzle to the cylinder side at the target volume based on the target volume; as well as A back-suction control step is to cause the screw to be back-sucked based on the back-suction distance or the back-suction time after the screw reaches the predetermined measurement position.

Citation Information

Patent Citations

  • Setting method of suck back amount and injection molding machine

    JP2008230164A