A method and system for vp switching mode of an oil hydraulic injection molding machine

Abstract

The application relates to a VP switching mode method and system of an oil pressure injection molding machine, which comprises the following steps: acquiring the actual position of a current screw rod in real time; when the actual position of the screw rod reaches a preset activation position, entering a product qualification judgment mode, acquiring the actual injection time of the screw rod in real time; comparing the actual injection time of the screw rod with a preset injection time range, judging and screening a bad condition; acquiring actual screw rod information in real time, under the condition that the actual screw rod information meets a pressure maintaining switching condition, controlling the screw rod to slow down and performing pressure switching mode operation on the screw rod, so that the screw rod enters a pressure maintaining stage; monitoring the pressure in real time after the screw rod is switched to the pressure maintaining stage, until the screw rod completes injection; acquiring the glue injection termination position of the screw rod, and comparing the glue injection termination position with a preset glue injection termination position range, judging a bad condition and screening. The application has the effect of ensuring that the screw rod can be smoothly switched to the pressure maintaining stage in the injection stage.

Description

Technical Field

[0001] This application relates to the field of injection molding machine technology, and in particular to a method and system for switching VP modes in a hydraulic injection molding machine. Background Technology

[0002] Injection molding is one of the most important polymer molding methods, processing more than one-third of the total polymer weight annually. An injection molding machine is the main molding equipment used to produce various shapes of plastic products from thermoplastic or thermosetting plastics using plastic molds. The injection molding machine heats the plastic, applies high pressure to the molten plastic, and injects it to fill the mold cavity. An injection molding machine consists of two parts: the mold and the injection mechanism. The injection mechanism can be further divided into several parts: the mold clamping mechanism, the injection mechanism, the hydraulic system, and the control system. The injection molding process includes several steps: mold clamping, injection, holding pressure, pre-plasticizing, cooling, mold opening, and ejection. Injection molding first uses a barrel and screw to heat the polymer raw material to a molten state, then injects it into a closed mold cavity through the injection screw. After holding pressure and cooling, the desired product is formed. During the injection filling process, when the mold cavity is almost full, the injected melt will shrink due to cooling. At this time, the screw must continue to move slowly to maintain pressure, allowing the melt in the injection screw to continue injecting into the cavity to meet the shrinkage requirements of the product. Therefore, at this point, the screw's movement needs to switch from flow rate control to pressure control. This transition point is called the holding pressure switching control point, or VP switching point. When the screw movement of the injection molding machine switches from speed control to pressure control, attention must be paid to the injection holding pressure of the injection molding machine. The control effect of the injection holding pressure process directly affects the final quality of the product. Therefore, it is necessary to accurately determine when the injection molding machine needs to switch the screw's speed control to pressure control so that the screw enters the holding pressure stage.

[0003] In related technologies, the switching method for switching the screw speed control to pressure control is to use position switching or time switching to bring the screw into the pressure holding stage. When the screw running time reaches the system preset time or the screw running position reaches the system preset position, the system will switch the screw speed control to pressure control.

[0004] However, neither pressure switching nor time switching takes into account the screw pressure or the pressure inside the mold cavity. This makes the system less smooth when switching from screw speed control to pressure control, and the screw pressure is unstable when entering the holding pressure stage, affecting the injection molding accuracy. Summary of the Invention

[0005] In order to improve the phenomenon that the switching from injection to holding pressure in related technologies is not smooth and affects the injection accuracy, this application provides a method and system for switching the VP mode of a hydraulic injection molding machine.

[0006] Firstly, this application provides a method for switching modes of a hydraulic injection molding machine's VP (Vibration Pressure) mode, which adopts the following technical solution:

[0007] A method for switching modes of a hydraulic injection molding machine (VP) includes the following steps:

[0008] The actual position of the screw is obtained in real time, and it is determined whether the actual position of the screw has reached the preset activation position, and whether to enter the product qualification judgment mode.

[0009] When the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, it enters the product qualification judgment mode and obtains the actual injection time of the screw in real time.

[0010] The actual injection time of the screw is compared with the preset injection time range to identify and screen for defects. The defective situation is that the injection work is unqualified and the screw operation needs to be terminated.

[0011] The system acquires real-time screw information. When the actual screw information meets the pressure holding switching conditions, it controls the screw to decelerate and performs a pressure switching mode operation to enable the screw to enter the pressure holding stage. The actual screw information includes the screw's injection time, the screw's actual position, and the screw's actual pressure. The pressure switching mode includes the system pressure control mode and the mold cavity pressure control mode.

[0012] After the screw is switched to the pressure holding stage, the pressure is monitored in real time until the screw completes the injection;

[0013] Obtain the injection termination position of the screw and compare it with the preset injection termination position range. If it is a defective condition, it is screened. After the screening is completed, the injection work is finished.

[0014] By adopting the above technical solution, the actual position of the screw is first acquired in real time when the screw starts injection to monitor the actual position of the screw and determine whether the actual position of the screw has reached the preset activation position. This determines whether the screw has entered the product qualification judgment mode. When the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, it is determined that the screw has entered the product qualification judgment mode. At this time, the actual injection time of the screw is acquired in real time and compared with the preset injection time to obtain the comparison result. In this process, defective situations are identified and screened in advance. After screening, the actual screw information is acquired in real time, and when the actual screw information meets the pressure holding switching conditions, the screw is controlled to decelerate and the pressure switching mode operation is performed on the screw. The pressure switching mode operation has two modes: system pressure control mode and mold cavity pressure control mode. The system can select any pair of screws to perform the pressure switching mode operation, so that the screw enters the pressure holding stage. After entering the pressure holding stage, the screw pressure is monitored in real time until the screw completes injection. After the screw stops injecting, the injection termination position of the screw is obtained and compared with the preset injection termination position range. After screening out defective cases, the entire injection process is completed. Throughout the screw injection process, a product qualification judgment mode is set to screen the screw operation before pressure control switching to identify defective cases. The screw speed control is switched to screw control only after the screw meets the pressure holding switching conditions. This accurate judgment of when to switch pressure ensures a smooth transition from speed control to pressure control, guaranteeing injection accuracy.

[0015] Furthermore, the pressure switching mode operation will only be activated when the actual position of the screw reaches the preset activation position; otherwise, it will be judged as a malfunction and the screw operation will be stopped.

[0016] By adopting the above technical solution, setting a preset activation position is to send a message to the system after the screw passes through the preset activation position so that the system can prepare in advance to switch the pressure of the screw. The preset activation position is also a criterion for judging whether the screw is operating normally.

[0017] Furthermore, the step of comparing the actual injection time of the screw with a preset injection time range to determine and screen for defective conditions includes the following steps:

[0018] Determine the maximum and minimum values ​​of the preset injection time range and compare them with the actual injection time of the screw;

[0019] If the actual injection time of the screw is less than the minimum value of the preset injection time range, it is judged as a defective situation and screened.

[0020] If the actual injection time of the screw is greater than the maximum value of the preset injection time range, it is judged as a defective situation and screened.

[0021] By adopting the above technical solution, the preset injection time range is configured in the system in advance. The actual injection time of the screw is compared with the minimum and maximum preset injection time respectively. When the actual injection time of the screw is less than the minimum preset injection time or greater than the maximum preset injection time, it will be judged as a defective situation by the system and screened.

[0022] Furthermore, the system pressure control mode involves real-time acquisition of the screw's injection time. Before the screw's injection time reaches the preset injection time, after the screw passes through the preset activation position, if the actual screw information meets one of the following pressure holding switching conditions, the system enters the pressure holding stage:

[0023] The actual pressure of the screw is obtained in real time when the screw's injection time has not reached the preset injection time and the actual position of the screw has not reached the preset VP switching position. The actual pressure of the screw reaches the preset switching pressure.

[0024] The screw's injection time has not reached the preset injection time and the screw's actual pressure has not reached the preset switching pressure. The screw's actual position is acquired in real time, and the screw's actual position reaches the preset VP switching position.

[0025] The actual position of the screw is not at the preset VP switching position and the actual pressure of the screw is not at the preset switching pressure. The injection time of the screw is obtained in real time. The injection time of the screw reaches the preset injection time.

[0026] By adopting the above technical solution, in the system pressure control mode, the screw injection time will be acquired in real time. Before the screw injection time reaches the preset injection time, after the screw passes the preset activation position, it will enter the pressure holding stage if the actual screw information meets one of the following pressure holding switching conditions: the screw injection time has not reached the preset injection time and the actual position of the screw has not reached the preset VP switching position, but the actual pressure of the screw reaches the preset switching pressure; the screw injection time has not reached the preset injection time and the actual pressure of the screw has not reached the preset switching pressure, but the actual position of the screw reaches the preset VP switching position; the screw injection time has reached the preset injection time.

[0027] Furthermore, the system pressure control mode acquires the screw injection time in real time. If the screw passes through a preset activation position before the screw injection time reaches the preset injection time, the following pressure holding switching condition is also included:

[0028] Before the actual position of the screw reaches the preset VP switching position, the actual pressure of the screw reaches the preset switching pressure. When the actual position of the screw reaches the preset VP switching position and stops, the injection time of the screw is greater than or equal to the preset injection time.

[0029] If the actual pressure of the screw is less than the preset switching pressure or the injection time of the screw is less than the preset injection time before the actual position of the screw reaches the preset VP switching position, it is judged as a bad situation and the screw operation is stopped.

[0030] By adopting the above technical solution, when the actual pressure of the screw reaches the preset switching pressure before the actual position of the screw reaches the preset VP switching position, and the speed of the screw is 0 after the actual position of the screw reaches the preset VP switching position, if the screw injection time at this time is greater than or equal to the preset injection time, it will switch to the holding pressure stage. However, if the actual pressure of the screw does not reach the preset switching pressure or the screw injection time is less than the preset injection time before the actual position of the screw reaches the preset VP switching position, the system will determine that the screw operation is malfunctioning and stop the screw operation.

[0031] Furthermore, the system pressure control mode also includes real-time acquisition of the screw's injection time. If the screw has not reached the preset activation position when the screw's injection time reaches the preset injection time, it is judged as a malfunction and the screw operation is stopped.

[0032] By adopting the above technical solution, when the screw is in system pressure control mode during screw operation, the screw injection time will be acquired in real time and compared with the system preset injection time. When the screw injection time has reached the preset injection time, it means that the screw should be pressure controlled. If the actual position of the screw has not passed the preset activation position, it means that the screw cannot trigger pressure control, and the screw operation will be terminated as a bad situation.

[0033] Furthermore, the mold cavity pressure control mode is to obtain the actual position of the screw in real time, obtain the actual pressure of the mold cavity before the actual position of the screw reaches the preset VP switching position, and enter the pressure holding stage when the actual pressure of the mold cavity reaches the preset switching pressure.

[0034] By adopting the above technical solution, when the screw is controlled in the mold cavity pressure mode, the actual position of the screw will be obtained in real time, and the actual pressure of the mold cavity will be obtained before the actual position of the screw reaches the preset VP switching position. This actual pressure of the mold cavity is the pressure value inside the mold cavity during the screw injection process. When this actual pressure of the mold cavity reaches the preset switching pressure, the pressure holding stage is entered.

[0035] Furthermore, the mold cavity pressure control mode also includes determining a malfunction and stopping screw operation when the actual screw information meets any of the following conditions:

[0036] The injection time of the screw is within the preset injection time range, and the actual pressure of the mold cavity has not reached the preset switching pressure;

[0037] When the actual position of the screw reaches the preset VP switching position, the actual pressure of the mold cavity has not reached the preset switching pressure;

[0038] When the actual pressure in the mold cavity reaches the preset switching pressure, the injection time of the screw is less than the preset injection time range.

[0039] By adopting the above technical solution, a defective situation is identified when the actual screw information meets one of the following conditions: the screw injection time is within the preset injection time range, but the actual pressure in the mold cavity has not reached the preset switching pressure; when the actual position of the screw reaches the preset VP switching position, it indicates that the control of the screw needs to be switched, but the actual pressure in the mold cavity has not reached the preset switching pressure; when the actual pressure in the mold cavity reaches the preset switching pressure, the screw injection time is less than the preset injection time range, that is, the screw injection time is not within the normal time range.

[0040] Furthermore, the step of obtaining the injection termination position of the screw and comparing it with a preset injection termination position range, determining it as a defective condition and screening it, includes the following steps:

[0041] Determine the maximum and minimum values ​​of the preset injection termination position range and compare them with the injection termination position of the screw;

[0042] If the screw's injection termination position is not within the preset injection termination position range before entering the pressure holding stage and after the screw has completed injection, it is considered an undesirable situation.

[0043] By adopting the above technical solution, the screw will stop running after completing the injection. The position of the screw at this time is the injection termination position of the screw. This injection termination position is compared with the preset injection termination position range. If the position is not within the preset injection termination position range, it will be judged as a defective situation and screened by the system.

[0044] Secondly, this application provides a VP switching mode system for a hydraulic injection molding machine, which adopts the following technical solution:

[0045] A hydraulic injection molding machine VP mode switching system includes:

[0046] The acquisition module acquires the actual position of the screw in real time and determines whether the actual position of the screw has reached the preset activation position, and determines whether to enter the product qualification judgment mode.

[0047] The discrimination module enters the product qualification discrimination mode when the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, and obtains the actual injection time of the screw in real time.

[0048] The first screening module compares the actual injection time of the screw with the preset injection time range, determines the defective situation, and screens it. The defective situation means that the injection work is unqualified and the screw operation needs to be terminated.

[0049] The comparison module acquires the actual screw information in real time. When the actual screw information meets the pressure holding switching conditions, it controls the screw to decelerate and performs a pressure switching mode operation on the screw, so that the screw enters the pressure holding stage. The actual screw information includes the screw injection time, the actual position of the screw, and the actual pressure of the screw. The pressure switching mode includes the system pressure control mode and the mold cavity pressure control mode.

[0050] The monitoring module monitors the pressure in real time after the screw switches to the pressure holding stage until the screw completes the injection.

[0051] The second screening module obtains the injection termination position of the screw and compares it with the preset injection termination position range. If it is a defective situation, it is screened. After the screening is completed, the injection work is finished.

[0052] By adopting the above technical solution, the acquisition module 1 obtains the actual position of the screw in real time and determines whether the actual position of the screw has reached the preset activation position to determine whether to enter the product qualification judgment mode. After the judgment module 2 determines that the actual position of the screw has reached the preset activation position, it enters the product qualification judgment mode and obtains the actual injection time of the screw and sends it to the first screening module 3. The first screening compares the actual injection time of the screw with the preset injection time range, judges the defective situation and performs screening. After the screening is completed, the comparison module 4, after obtaining the actual screw information, controls the screw to decelerate and performs pressure switching mode operation on the screw if the actual screw information meets the pressure holding switching conditions, so as to enter the pressure holding stage. After the screw enters the pressure holding stage, the monitoring module 5 monitors the pressure in real time until the screw completes the injection. After the screw completes the injection, the second screening module 6 obtains the injection termination position of the screw and compares it with the preset injection termination position range to screen the defective situation again. After the screening is completed, the screw completes all the work.

[0053] In summary, this application includes at least one of the following beneficial technical effects:

[0054] 1. Throughout the screw injection process, a product qualification judgment mode is set to screen the screw operation before pressure control switching to identify defective situations. Only after the screw meets the pressure holding switching conditions is the speed control of the screw switched to screw control. After the entire screw injection is completed, the normal operation of the screw is screened again. By setting two pressure switching modes, the timing of pressure switching can be accurately determined, so that the screw can smoothly switch from speed control to pressure control, ensuring the accuracy of injection.

[0055] 2. Set a preset activation position before the preset VP switching position. The pressure control switching of the screw can only be activated after the screw runs to the preset activation position. The preset activation position allows the system to prepare in advance to switch the pressure of the screw. The preset activation position is also a criterion for judging whether the screw is running normally. Attached Figure Description

[0056] Figure 1 This application provides a flowchart of a method for switching the VP mode of a hydraulic injection molding machine;

[0057] Figure 2 This is a flowchart of the operation of S3 in this application;

[0058] Figure 3 This is a flowchart of the system pressure control mode operation in this application;

[0059] Figure 4 This is a flowchart of the operation of the cavity pressure control mode in this application;

[0060] Figure 5 This is a flowchart of the operation of S6 in this application;

[0061] Figure 6 This is a flowchart of a VP switching mode system for a hydraulic injection molding machine provided in this application.

[0062] In the diagram, 1 is the acquisition module; 2 is the discrimination module; 3 is the first filtering module; 4 is the comparison module; 5 is the monitoring module; and 6 is the second filtering module. Detailed Implementation

[0063] The following is in conjunction with the appendix Figure 1 - Appendix Figure 6 This application will be described in further detail below.

[0064] In order to smoothly switch from speed control to pressure control of the screw, so that the screw enters the pressure holding stage, this application provides a method and system for switching the VP mode of a hydraulic injection molding machine.

[0065] This application discloses a method for switching modes of a hydraulic injection molding machine (VP), such as... Figure 1As shown:

[0066] A method for switching VP modes in a hydraulic injection molding machine, referring to Figure 1 This includes the following steps:

[0067] S1. Obtain the actual position of the screw in real time, and determine whether the actual position of the screw has reached the preset activation position, and determine whether to enter the product qualification judgment mode.

[0068] Specifically, injection molding machines mainly involve two important stages during injection molding: the injection stage and the holding pressure stage. In the injection stage, the screw speed is controlled to propel the molten material from the barrel into the mold cavity at a certain speed. The holding pressure stage switches the screw speed control to pressure control, forcing any remaining molten material in the barrel to be extruded into the mold cavity under pressure. Throughout the entire operation of the injection molding machine, screw movement is controlled. First, the screw needs to be given a certain speed. Once the screw reaches this speed, the molten material in the barrel is ejected from the nozzle and enters the mold cavity to fill it; this process is the injection stage. When most of the molten material in the barrel has been injected into the mold cavity, filling it to approximately 90% to 99% of its volume, the screw speed control needs to be switched to pressure control. This occurs when the screw passes the VP switching point, which automatically triggers the switch back to pressure control. At this point, there is still molten material remaining in the feed tube, and the molten material in the mold cavity shrinks after cooling. Pressure control of the screw can make the screw push the remaining molten material into the mold cavity to completely fill the gaps in the entire mold cavity.

[0069] In this embodiment, a preset activation position is set during screw operation. This preset activation position is the trigger point for the screw to switch VP (Power Transfer Voltage). The preset activation position is set in advance by the system before each injection molding. After the screw reaches the preset activation position, the screw operation undergoes its first quality check, i.e., it enters the product qualification judgment mode. The product qualification judgment mode checks the quality of the current screw operation to determine whether the screw is operating normally, thus laying the groundwork for subsequent pressure control of the screw.

[0070] S2. When the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, the product qualification judgment mode is entered, and the actual injection time of the screw is obtained in real time.

[0071] Once the screw reaches the preset activation position but before reaching the preset VP switching position, the system enters the product qualification judgment mode. Specifically, the preset VP switching position is the VP switching point, which is the point at which the screw's speed control switches to pressure control. After the screw reaches the preset VP switching point, the system switches the screw speed control to pressure control, allowing the screw to continue running and fill the remaining melt into the mold cavity, ensuring the successful completion of this injection molding. The screw only reaches the preset VP switching position after reaching the preset activation position. The preset activation position precedes the preset VP position, effectively alerting the system to prepare beforehand so that the screw can automatically switch upon reaching the preset VP switching position.

[0072] When the screw reaches the preset activation position and before the preset VP switching position, it will automatically enter the product qualification judgment mode. At this time, the actual injection time of the screw is acquired in real time, and the following steps are performed:

[0073] S3. Compare the actual injection time of the screw with the preset injection time range, identify and screen for defects. Defective conditions indicate that the injection operation is unqualified and the screw operation needs to be terminated.

[0074] Specifically, the preset injection time range is set in the system beforehand. This range represents the time it takes for the screw to reach the preset VP position under normal operating conditions, allowing the system to determine whether the actual injection time of the screw is within the normal range. After comparing the actual injection time of the screw with the preset injection time range, screws that are outside the preset injection time range will be identified. In this case, the screw operation needs to be judged as a defective condition and screened. A defective condition means that the injection operation of the screw is abnormal and the screw operation needs to be terminated in time.

[0075] Specifically, the actual injection time of the screw is compared with the preset injection time range to identify and screen for defective products, referring to... Figure 2 This includes the following steps:

[0076] S31. Determine the maximum and minimum values ​​of the preset injection time range and compare them with the actual injection time of the screw.

[0077] The system has a pre-set injection time range with a maximum and a minimum value. The maximum and minimum values ​​together form the interval of the pre-set injection time range, which is convenient for comparison with the actual injection time of the screw and to obtain the comparison result as soon as possible.

[0078] S32. If the actual injection time of the screw is less than the minimum value of the preset injection time range, it is judged as a defective situation and screened.

[0079] Before the screw reaches the preset VP switching position, the actual injection time of the screw is acquired in real time and compared with the minimum value of the preset injection time range. If the actual injection time of the screw is less than the minimum value of the preset injection time range before the screw reaches the preset VP position, it means that the actual injection time of the screw is not within the preset injection time range, which further indicates that the actual injection time of the screw is not operating normally. At this time, the system will automatically judge it as a bad situation and terminate the action of the screw.

[0080] S33. If the actual injection time of the screw is greater than the maximum value of the preset injection time range, it is judged as a defective situation and screened.

[0081] Before the screw reaches the preset VP switching position, the actual injection time of the screw is acquired in real time and compared with the maximum value of the preset injection time range. At this point, the actual injection time has already been compared with the minimum value of the preset injection time range, indicating that the actual injection time is greater than the minimum value, and it can proceed to the comparison with the maximum value of the preset injection time range. If the actual injection time of the screw is greater than the maximum value of the preset injection time range before reaching the preset VP position, it indicates that the actual injection time of the screw exceeds the preset injection time range, and the screw's actual injection time is abnormal. The system will automatically identify this as a defective situation and filter it out.

[0082] After comparing the actual injection time of the screw with the preset injection time range, the following steps are performed:

[0083] S4. Real-time acquisition of actual screw information. When the actual screw information meets the pressure holding switching conditions, control the screw to decelerate and perform pressure switching mode operation on the screw so that the screw enters the pressure holding stage. The actual screw information includes the screw injection time, the actual position of the screw, and the actual pressure of the screw. The pressure switching mode includes system pressure control mode and mold cavity pressure control mode.

[0084] Specifically, before the screw reaches the preset VP position, the actual screw information is acquired in real time. This actual screw information includes the screw's injection time, actual position, and actual pressure. Multiple pieces of information are used to determine whether the screw can meet the pressure holding switching condition. In this embodiment, the pressure holding switching condition is whether the screw's speed control can be switched to pressure control. Therefore, judging the actual screw information at this time is crucial. If the actual screw information meets the pressure holding switching condition, the system will control the screw to decelerate and perform a pressure switching mode operation to allow the screw to enter the pressure holding stage. The pressure switching modes include system pressure control mode and mold cavity pressure control mode. Both pressure switching modes can accurately determine whether the screw can switch from speed control to pressure control. In actual use, either mode can be selected to perform the pressure switching mode operation on the screw, ensuring the screw smoothly enters the pressure holding stage.

[0085] Specifically, refer to Figure 3 The system pressure control mode includes the following steps:

[0086] S41. The system pressure control mode is to acquire the screw injection time in real time. Before the screw injection time reaches the preset injection time, after the screw passes the preset activation position, if the actual screw information meets one of the following pressure holding switching conditions, it will enter the pressure holding stage:

[0087] During the system pressure control mode of the screw, it is necessary to acquire the screw's injection time in real time. The screw must enter the pressure holding stage before its injection time reaches the preset injection time and after it passes the preset activation position, provided that one of the actual screw information meets the pressure holding switching condition. Specifically, the preset injection time is the total time from the start of injection to the required pressure switching. Pressure switching can only be performed on the screw before the injection time reaches the preset injection time. Furthermore, the screw must pass the preset activation position before system pressure control can continue.

[0088] If the actual screw information meets one of the following pressure holding switching conditions, the pressure holding stage will begin:

[0089] 1. Pressure: The screw's injection time has not reached the preset injection time and the screw's actual position has not reached the preset VP switching position. The actual pressure of the screw is obtained in real time. The actual pressure of the screw reaches the preset switching pressure.

[0090] When the screw's injection time has not reached the preset injection time and the screw's actual position has passed the preset activation position but has not reached the preset VP switching position, the actual screw pressure is acquired in real time. If the actual screw pressure reaches the preset switching pressure, the system determines that the screw's actual screw information meets the pressure holding switching conditions and can enter the pressure holding stage. Specifically, the actual screw pressure is the pressure generated by the screw during operation, and the preset switching pressure is configured in advance in the system to determine whether the screw's actual pressure has reached the preset switching pressure, thereby determining whether the screw meets the pressure holding switching conditions.

[0091] 2. Position: The screw's injection time has not reached the preset injection time and the screw's actual pressure has not reached the preset switching pressure. The screw's actual position is obtained in real time. The screw's actual position reaches the preset VP switching position.

[0092] When the screw's injection time has not reached the preset injection time and the screw's actual pressure has not reached the preset switching pressure, the actual position of the screw is acquired in real time. Once the actual position of the screw reaches the preset VP switching position, the system determines that the actual screw information meets the pressure holding switching conditions and can enter the pressure holding stage.

[0093] (3) Time: The actual position of the screw has not reached the preset VP switching position and the actual pressure of the screw has not reached the preset switching pressure. The injection time of the screw is obtained in real time. The injection time of the screw reaches the preset injection time.

[0094] When the actual position of the screw is not at the preset VP position and the actual pressure of the screw is not at the preset switching pressure, the screw injection time is acquired in real time and compared with the preset injection time. When the screw injection time reaches the preset injection time, the system determines that the actual screw information meets the pressure holding switching conditions and can enter the pressure holding stage.

[0095] When determining whether the actual screw information meets the pressure holding switching conditions, the three screw parameters—screw injection time, screw actual position, and screw actual pressure—are compared with the three system parameters—preset injection time, preset VP switching position, and preset switching pressure. As long as one of the screw information reaches the corresponding system parameter, the speed control of the screw can be switched to pressure control, allowing the screw to enter the pressure holding stage.

[0096] In addition to the above, the system pressure control mode also includes the following steps:

[0097] S42. In the system pressure control mode, the screw injection time is acquired in real time. If the screw passes through the preset activation position before the screw injection time reaches the preset injection time, the following pressure holding switching conditions are also included:

[0098] 1. Position + Pressure + Time: Before the actual position of the screw reaches the preset VP switching position, the actual pressure of the screw reaches the preset switching pressure. When the actual position of the screw reaches the preset VP switching position and stops, the screw injection time is greater than or equal to the preset injection time.

[0099] Before the actual position of the screw reaches the preset VP switching position, and the actual pressure of the screw reaches the preset switching pressure, if the actual position of the screw reaches the preset VP switching position and the speed is 0, and if the screw injection time at this time is greater than or equal to the preset injection time, then the process switches to the holding pressure stage. The difference between this holding pressure switching condition and S41 is that S41 switches to the holding pressure stage when a certain actual screw information corresponds to a preset system parameter. In S42, the screw injection time, actual position, and actual pressure from the actual screw information are combined to determine whether the screw meets the holding pressure switching condition and can enter the holding pressure stage. Both S41 and S42 can be used to determine whether the screw meets the holding pressure switching condition and enters the holding pressure stage.

[0100] 2. If the actual pressure of the screw does not reach the preset switching pressure or the injection time of the screw is less than the preset injection time before the actual position of the screw reaches the preset VP switching position, it is judged as a bad situation and the screw operation is stopped.

[0101] If, before the screw's actual position reaches the preset VP switching position, the screw's actual pressure is below the preset switching pressure or the screw's injection time is less than the preset injection time, the system will determine that the screw operation is malfunctioning and stop the screw operation. In this pressure-holding switching condition, if the screw's actual position has not reached the preset VP switching position, or if either the screw's actual pressure or the screw's injection time does not meet the system's preset conditions, it will be considered malfunctioning and the screw operation must be stopped.

[0102] In addition to the above, the system pressure control mode also includes the following steps:

[0103] S43. The system pressure control mode also includes real-time acquisition of the screw's injection time. If the screw has not reached the preset activation position when the screw's injection time reaches the preset injection time, it is judged as a malfunction and the screw operation is stopped.

[0104] During screw operation in system pressure control mode, the screw's injection time is acquired in real time and compared with the system's preset injection time. When the screw's injection time has reached the preset injection time, it indicates that pressure control should be initiated. However, if the screw's actual position has not passed the preset activation position, it means that pressure control cannot be triggered, and this is considered a malfunction, causing the screw's operation to be terminated. Specifically, if the screw's actual position has not passed the preset activation position, it means that pressure control cannot be activated, and the screw will continue to run at its original speed until injection is complete. If the screw continues to run at its original speed, it will adversely affect the product, so the screw's operation must be terminated promptly.

[0105] In addition to the system pressure control mode, the pressure switching mode also includes a mold cavity pressure control mode, see reference. Figure 4 Specifically, as follows:

[0106] S41. The mold cavity pressure control mode is to obtain the actual position of the screw in real time, obtain the actual pressure of the mold cavity before the actual position of the screw reaches the preset VP switching position, and enter the pressure holding stage when the actual pressure of the mold cavity reaches the preset switching pressure.

[0107] When the screw is in cavity pressure control mode, the actual position of the screw is acquired in real time. Before the actual position of the screw reaches the preset VP switching position, the actual cavity pressure is acquired. This actual cavity pressure is the pressure value inside the cavity during the screw injection process. When this actual cavity pressure reaches the preset switching pressure, the pressure holding stage begins.

[0108] In the mold cavity pressure control mode, the actual pressure of the mold cavity is used as the trigger point for whether the screw enters the pressure holding stage. Before the actual position of the screw reaches the preset VP switching position, the pressure holding stage is entered as long as the actual pressure of the mold cavity reaches the preset switching pressure.

[0109] The cavity pressure control mode also includes the following steps:

[0110] S42. The cavity pressure control mode also includes determining a problem and stopping screw operation when the actual screw information meets any of the following conditions:

[0111] In the cavity pressure control mode, some adverse situations may occur. These adverse situations need to be identified in time and the screw operation should be terminated.

[0112] 1. The screw injection time is within the preset injection time range, but the actual pressure in the mold cavity has not reached the preset switching pressure;

[0113] If the actual injection time of the screw is within the preset injection time range, but the actual pressure of the mold cavity does not reach the preset switching pressure, it means that the actual pressure of the mold cavity does not meet the system standard, and will be judged as a defective situation by the system and screened.

[0114] 2. When the actual position of the screw reaches the preset VP switching position, the actual pressure in the mold cavity has not reached the preset switching pressure;

[0115] When the actual position of the screw reaches the preset VP switching position, it indicates that the control of the screw needs to be switched. However, the actual pressure of the mold cavity at this time has not reached the preset switching pressure, indicating that there is a problem with the screw operation. The system will automatically judge it as a bad situation and terminate the operation of the screw.

[0116] 3. When the actual pressure in the mold cavity reaches the preset switching pressure, the injection time of the screw is less than the preset injection time range.

[0117] When the actual pressure in the mold cavity reaches the preset switching pressure, the screw's injection time is less than the preset injection time range, meaning the screw's injection time is not within the normal time range. At this time, the system will automatically judge it as a defective situation and filter it.

[0118] Once the screw enters the pressure holding stage, the following steps are performed:

[0119] S5. After the screw is switched to the pressure holding stage, the pressure is monitored in real time until the screw completes the injection.

[0120] After the screw switches to the pressure holding stage, the screw pressure is monitored to ensure that the screw operates normally after switching to the pressure holding stage. The screw pressure monitoring stops after the screw completes the injection.

[0121] After the screw completes the injection and stops, a second quality inspection is required to determine whether the injection process was completed successfully.

[0122] S6. Obtain the injection termination position of the screw and compare it with the preset injection termination position range. If it is a defective situation, it is screened. After the screening is completed, the injection work is completed.

[0123] After the screw completes the injection process, it will stop running. The position of the screw at this time is the injection termination position. This injection termination position is compared with the preset injection termination position range. If it is not within the preset injection termination position range, it will be judged as a defective situation and screened out by the system.

[0124] Specifically, refer to Figure 5 Perform the following steps:

[0125] S61. Determine the maximum and minimum values ​​of the preset injection termination position range and compare them with the injection termination position of the screw.

[0126] The system has a pre-configured range of preset injection termination positions with a maximum and a minimum value. The maximum value is the farthest position reached after the screw stops injection, and the minimum value is the closest position reached after the screw stops injection. The position between the maximum and minimum values ​​forms the preset injection termination position range. If the screw's injection termination position is within the preset injection termination position range, it is normal; otherwise, it is a defective situation.

[0127] S62. If the screw's injection termination position is not within the preset injection termination position range before entering the pressure holding stage or after the screw has finished injection, it is considered a defective situation.

[0128] Before entering the pressure holding stage and after injection, the screw's injection termination position is considered normal if it falls within the preset termination position range. If the screw's injection termination position does not reach the minimum or maximum value of the preset termination position range, it is considered a defect, indicating that the injection process is abnormal. Only after this judgment is made is the screw considered to have completed a full injection process.

[0129] This application also discloses a VP switching mode system for a hydraulic injection molding machine.

[0130] A hydraulic injection molding machine VP mode switching system, referring to Figure 6 ,include:

[0131] Module 1 acquires the current actual position of the screw in real time and determines whether the actual position of the screw has reached the preset activation position, and determines whether to enter the product qualification judgment mode;

[0132] The discrimination module 2 enters the product qualification discrimination mode when the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, and obtains the actual injection time of the screw in real time.

[0133] The first screening module 3 compares the actual injection time of the screw with the preset injection time range, judges it as a defective situation and screens it. The defective situation means that the injection work is unqualified and the screw operation needs to be terminated.

[0134] Comparison module 4 acquires the actual screw information in real time. When the actual screw information meets the pressure holding switching conditions, it controls the screw to decelerate and performs a pressure switching mode operation on the screw, so that the screw enters the pressure holding stage. The actual screw information includes the screw injection time, the actual position of the screw, and the actual pressure of the screw. The pressure switching mode includes the system pressure control mode and the mold cavity pressure control mode.

[0135] Monitoring module 5 monitors the pressure in real time after the screw switches to the holding stage until the screw completes the injection;

[0136] The second screening module 6 obtains the injection termination position of the screw and compares it with the preset injection termination position range. If it is a defective situation, it is screened. After the screening is completed, the injection work is finished.

[0137] The acquisition module 1 acquires the actual position of the screw in real time and determines whether the actual position of the screw has reached the preset activation position to determine whether to enter the product qualification judgment mode. After the judgment module 2 determines that the actual position of the screw has reached the preset activation position, it enters the product qualification judgment mode and acquires the actual injection time of the screw and sends it to the first screening module 3. The first screening module 3 compares the actual injection time of the screw with the preset injection time range, identifies the defective cases and performs screening. After screening, the comparison module 4, after acquiring the actual screw information, controls the screw to decelerate and performs pressure switching mode operation on the screw if the actual screw information meets the pressure holding switching conditions, so as to enter the pressure holding stage. After the screw enters the pressure holding stage, the monitoring module 5 monitors the pressure in real time until the screw completes the injection. After the screw completes the injection, the second screening module 6 acquires the injection termination position of the screw and compares it with the preset injection termination position range to screen the defective cases again. After screening, the screw completes all work.

[0138] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for switching VP modes in a hydraulic injection molding machine, characterized in that, Includes the following steps: The actual position of the screw is obtained in real time, and it is determined whether the actual position of the screw has reached the preset activation position, and whether to enter the product qualification judgment mode. When the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, it enters the product qualification judgment mode and obtains the actual injection time of the screw in real time. The actual injection time of the screw is compared with the preset injection time range to identify and screen for defects. The defective situation is that the injection work is unqualified and the screw operation needs to be terminated. The system acquires real-time screw information. When the actual screw information meets the pressure holding switching conditions, it controls the screw to decelerate and performs a pressure switching mode operation to enable the screw to enter the pressure holding stage. The actual screw information includes the screw's injection time, the screw's actual position, and the screw's actual pressure. The pressure switching mode includes the system pressure control mode and the mold cavity pressure control mode. After the screw is switched to the pressure holding stage, the pressure is monitored in real time until the screw completes the injection; Obtain the injection termination position of the screw and compare it with the preset injection termination position range. If it is a defective situation, it is screened. After the screening is completed, the injection work is completed. The system pressure control mode acquires the screw's injection time in real time. Before the screw's injection time reaches the preset injection time, after the screw passes the preset activation position, if the actual screw information meets one of the following pressure holding switching conditions, it enters the pressure holding stage: The actual pressure of the screw is obtained in real time when the screw's injection time has not reached the preset injection time and the actual position of the screw has not reached the preset VP switching position. The actual pressure of the screw reaches the preset switching pressure. The screw's injection time has not reached the preset injection time and the screw's actual pressure has not reached the preset switching pressure. The screw's actual position is acquired in real time, and the screw's actual position reaches the preset VP switching position. The actual position of the screw is not at the preset VP switching position and the actual pressure of the screw is not at the preset switching pressure. The injection time of the screw is obtained in real time. The injection time of the screw reaches the preset injection time. The mold cavity pressure control mode is to obtain the actual position of the screw in real time, obtain the actual pressure of the mold cavity before the actual position of the screw reaches the preset VP switching position, and enter the pressure holding stage when the actual pressure of the mold cavity reaches the preset switching pressure.

2. The method for switching VP modes in a hydraulic injection molding machine according to claim 1, characterized in that, The pressure switching mode operation will only be activated when the actual position of the screw reaches the preset activation position; otherwise, it will be judged as a malfunction and the screw operation will be stopped.

3. The method for switching VP modes in a hydraulic injection molding machine according to claim 1, characterized in that, The process of comparing the actual injection time of the screw with a preset injection time range to determine and screen for defective products includes the following steps: Determine the maximum and minimum values ​​of the preset injection time range and compare them with the actual injection time of the screw; If the actual injection time of the screw is less than the minimum value of the preset injection time range, it is judged as a defective situation and screened. If the actual injection time of the screw is greater than the maximum value of the preset injection time range, it is judged as a defective situation and screened.

4. The method for switching VP modes of a hydraulic injection molding machine according to claim 1, characterized in that, The system pressure control mode acquires the screw's injection time in real time. If the screw passes a preset activation position before the injection time reaches the preset injection time, the following pressure holding switching condition is also included: Before the actual position of the screw reaches the preset VP switching position, the actual pressure of the screw reaches the preset switching pressure. When the actual position of the screw reaches the preset VP switching position and stops, the injection time of the screw is greater than or equal to the preset injection time. If the actual pressure of the screw is less than the preset switching pressure or the injection time of the screw is less than the preset injection time before the actual position of the screw reaches the preset VP switching position, it is judged as a bad situation and the screw operation is stopped.

5. The method for switching VP modes in a hydraulic injection molding machine according to claim 1, characterized in that, The system pressure control mode also includes real-time acquisition of the screw's injection time. If the screw has not reached the preset activation position when the screw's injection time reaches the preset injection time, it is judged as a malfunction and the screw operation is stopped.

6. The method for switching VP modes of a hydraulic injection molding machine according to claim 1, characterized in that, The mold cavity pressure control mode also includes determining a malfunction and stopping screw operation when the actual screw information meets any of the following conditions: The injection time of the screw is within the preset injection time range, and the actual pressure of the mold cavity has not reached the preset switching pressure; When the actual position of the screw reaches the preset VP switching position, the actual pressure of the mold cavity has not reached the preset switching pressure; When the actual pressure in the mold cavity reaches the preset switching pressure, the injection time of the screw is less than the preset injection time range.

7. The method for switching VP modes of a hydraulic injection molding machine according to claim 1, characterized in that, The process of obtaining the injection termination position of the screw and comparing it with a preset injection termination position range, determining it as a defective condition and filtering it, includes the following steps: Determine the maximum and minimum values ​​of the preset injection termination position range and compare them with the injection termination position of the screw; If the screw's injection termination position is not within the preset injection termination position range before entering the pressure holding stage and after the screw has completed injection, it is considered an undesirable situation.

8. A VP switching mode system for a hydraulic injection molding machine, employing the VP switching mode method for a hydraulic injection molding machine as described in any one of claims 1-7, characterized in that, include: The acquisition module acquires the actual position of the screw in real time and determines whether the actual position of the screw has reached the preset activation position, and determines whether to enter the product qualification judgment mode. The discrimination module enters the product qualification discrimination mode when the actual position of the screw reaches the preset activation position and before reaching the preset VP switching position, and obtains the actual injection time of the screw in real time. The first screening module compares the actual injection time of the screw with the preset injection time range, determines the defective situation, and screens it. The defective situation means that the injection work is unqualified and the screw operation needs to be terminated. The comparison module acquires the actual screw information in real time. When the actual screw information meets the pressure holding switching conditions, it controls the screw to decelerate and performs a pressure switching mode operation on the screw, so that the screw enters the pressure holding stage. The actual screw information includes the screw injection time, the actual position of the screw, and the actual pressure of the screw. The pressure switching mode includes the system pressure control mode and the mold cavity pressure control mode. The monitoring module monitors the pressure in real time after the screw switches to the pressure holding stage until the screw completes the injection. The second screening module obtains the injection termination position of the screw and compares it with the preset injection termination position range. If it is a defective situation, it is screened. After the screening is completed, the injection work is finished. The system pressure control mode acquires the screw's injection time in real time. Before the screw's injection time reaches the preset injection time, after the screw passes the preset activation position, if the actual screw information meets one of the following pressure holding switching conditions, it enters the pressure holding stage: The actual pressure of the screw is obtained in real time when the screw's injection time has not reached the preset injection time and the actual position of the screw has not reached the preset VP switching position. The actual pressure of the screw reaches the preset switching pressure. The screw's injection time has not reached the preset injection time and the screw's actual pressure has not reached the preset switching pressure. The screw's actual position is acquired in real time, and the screw's actual position reaches the preset VP switching position. The actual position of the screw is not at the preset VP switching position and the actual pressure of the screw is not at the preset switching pressure. The injection time of the screw is obtained in real time. The injection time of the screw reaches the preset injection time. The mold cavity pressure control mode is to obtain the actual position of the screw in real time, obtain the actual pressure of the mold cavity before the actual position of the screw reaches the preset VP switching position, and enter the pressure holding stage when the actual pressure of the mold cavity reaches the preset switching pressure.

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