Programmable control method and system for safety of injection molding machine

Abstract

The invention discloses a programmable control method and system for injection molding machine safety, and relates to the technical field of injection molding machine safety control, and the method comprises the following steps: S1, collecting multiple paths of safety input signals of an injection molding machine, the safety input signals at least comprising an emergency stop signal, a safety door state signal and an authority key signal; s2, determining an operation mode of the injection molding machine based on the permission key signal, performing logic combination judgment on the safety input signal, the current execution action and the operation mode through a programmable logic controller, and determining a safety response strategy in a corresponding safety decision rule according to a pre-constructed corresponding relationship between a logic combination and the safety decision rule; and S3, controlling an execution mechanism of the injection molding machine to output a corresponding shutdown control instruction according to the safety response strategy, so that the injection molding machine executes the shutdown type action with the highest safety level. The problems that an existing injection molding machine safety control mode depends on fixed hard wiring and is difficult to adapt to different operation modes and multi-signal simultaneous triggering scenes are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of injection molding machine safety control, and in particular to a programmable control method and system for injection molding machine safety. BACKGROUND

[0002] Currently, most traditional control methods rely on relays to achieve oil pump output and alarm output control. Relays use electromagnetic fields to attract and release contacts for circuit opening. Although this method is simple and reliable, it has some obvious limitations. First, there is mechanical delay in the relay attraction and release process, and the response time is relatively slow, which may cause control lag in some scenarios that require fast response. In addition, when relays open and close load switches, the generation of electric arcs will burn the contacts, thereby increasing mechanical wear and posing certain safety hazards. The traditional technology also has the problem of low automation and intelligence. Relays are only used as switching elements and cannot perform more complex control operations or monitor the action state of other devices, which limits the multifunctionality and intelligence level of the system. Finally, the existing technology only relies on traditional buzzers for alarm, lacking more comprehensive safety measures. Once the buzzer fails, it will not be possible to determine whether the device has failed through other means, thereby posing potential safety hazards. More importantly, these existing control technologies cannot meet the current safety standards for device performance levels, leaving room for further improvement. SUMMARY

[0003] Therefore, the present application provides a programmable control method and system for injection molding machine safety to solve the technical problems in the prior art that injection molding machine safety control mainly relies on fixed hard-wired logic or single safety signal judgment, and cannot dynamically adjust safety response strategies according to the running mode and current execution action of the injection molding machine.

[0004] To achieve the above-mentioned purpose, the present application provides a programmable control method for injection molding machine safety, comprising S1: collecting multiple safety input signals of the injection molding machine, the safety input signals at least including an emergency stop signal, a safety door state signal and a permission key signal; S2: determining the running mode of the injection molding machine based on the permission key signal, logically combining the safety input signals, the current execution action and the running mode through a programmable logic controller, determining the safety response strategy in the corresponding safety decision rule according to the corresponding relationship between the pre-constructed logic combination and the safety decision rule; and S3: controlling the injection molding machine execution mechanism to output the corresponding stop control instruction according to the safety response strategy, so that the injection molding machine performs the action of the highest safety level stop category.

[0005] Based on the above embodiment, the safety decision rule is stored in the programmable logic controller in a parameterized manner, supporting configuration according to injection molding machine model, mold type or process parameters.

[0006] Based on the above embodiment, the execution action is divided into high-risk action and low-risk action.

[0007] Based on the above embodiment, the high-risk action includes clamping action, platen advancing action and injection action, and the low-risk action includes ejection action and glue melting action.

[0008] Based on the above embodiment, the operation mode at least includes production mode and maintenance mode, in the maintenance mode, the execution of the high-risk action is prohibited, and the low-risk action is allowed to continue to execute when the safety condition is met.

[0009] Based on the above embodiment, the correspondence between the logical combination in step S2 and the safety decision rule includes at least one combination defined in the following table:

[0011] Based on the above embodiment, in step S3, the shutdown category at least includes:

[0013] Based on the above embodiment, when a plurality of safety input signals are triggered at the same time, based on the preset safety decision rule, the programmable logic controller outputs corresponding shutdown control instructions to the injection molding machine actuator, and the safety level priority is sorted in the order of emergency stop signal, safety door signal and permission key signal, so that the injection molding machine performs the action of the highest safety level shutdown category.

[0014] Based on the above embodiment, during the safety strategy execution process, the programmable logic controller calls a plurality of hierarchical task blocks, including a high-priority organization block for real-time safety response, a logic processing block for operation mode switching, and a diagnostic block for log recording.

[0015] Another aspect of the present application provides a programmable control system for injection molding machine safety, comprising a safety input acquisition module, a control decision module, an authority level determination module, a safety strategy storage module, a programmable safety logic module and an actuator control module, the safety input acquisition module is used to acquire multiple safety inputs including at least emergency stop signal, safety door signal and authority key signal; the control decision module is electrically connected with the safety input acquisition module, the control decision module includes a programmable logic controller, which is used to identify the current execution action of the injection molding machine, and divide the execution action into high-risk action and low-risk action, determine the operation mode of the injection molding machine according to the authority key signal, and perform logical combination judgment on the safety input signal, the current execution action and the operation mode to generate a corresponding safety response strategy; the authority level determination module is used to determine the target operation mode based on the authority key signal, including at least production mode, maintenance mode and emergency stop mode; the safety strategy storage module is used to store the safety response strategy corresponding to different safety input combinations; the actuator control module is used to execute full stop, controlled speed reduction stop or selective action inhibition of the actuator according to the safety control strategy.

[0016] Compared with the prior art, the present application has beneficial effects. The present application unifies the acquisition and logical fusion of multiple safety inputs such as emergency stop signal, safety door state signal and authority key signal through programmable logic controller, and comprehensively judges in combination with the current execution action and operation mode of the injection molding machine, so that the injection molding machine can automatically execute the highest safety level stop action in the case of simultaneous triggering of multiple safety signals, avoiding the problem of unclear safety response caused by signal conflict or fixed judgment in the traditional safety control mode; at the same time, by storing and configuring the safety decision rules in a parameterized manner, the safety control strategy can be flexibly adjusted according to different injection molding machine models, mold types or process parameters, improving the versatility and adaptability of the system; in addition, the present application classifies the execution action into high-risk and low-risk levels, and implements differentiated control in production mode and maintenance mode, balancing the equipment operation efficiency and maintenance convenience on the premise of ensuring personnel and equipment safety; further, by introducing the safety level priority mechanism and the safety strategy execution mode of hierarchical task blocks, the real-time performance, reliability and maintainability of safety response are improved, which is suitable for various injection molding machine safety control scenes. DETAILED DESCRIPTION

[0017] The technical solutions of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments.

[0018] The components of the embodiments of the application described and illustrated herein can be arranged and designed in a wide variety of different configurations. Therefore, the following detailed description of the embodiments of the application, as represented in the figures, is not intended to limit the scope of the application, but is merely representative of selected embodiments of the application.

[0019] All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present application without creative work are within the scope of protection of the present application.

[0020] The terms "first", "second", and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of use in either order. Furthermore, the term "comprising" as used in the detailed description and in the claims of the application is not intended to exclude any embodiments of the application having any elements not specified or inherent to the system, composition, method, process or article. No component is essential unless the application as a whole necessarily requires it. It is appreciated that certain features of the application, which are, for example, well known in the art, are not described, or are described only in a summary fashion in the course of the specification to avoid obscuring aspects of the present application.

[0021] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is appreciated that the embodiments described herein can be combined with other embodiments.

[0022] A programmable control method for injection molding machine safety, comprising: S1: collecting a plurality of safety input signals of the injection molding machine, the safety input signals at least including an emergency stop signal, a safety door state signal and a permission key signal; S2: determining the operation mode of the injection molding machine based on the permission key signal, logically combining the safety input signals, the current execution action and the operation mode by a programmable logic controller, determining the safety response strategy in the corresponding safety decision rule according to the corresponding relationship between the pre-constructed logical combination and the safety decision rule; S3: controlling the injection molding machine execution mechanism to output the corresponding stop control instruction according to the safety response strategy, so that the injection molding machine executes the stop category action with the highest safety level.

[0023] Further, the safety decision rule is stored in the programmable logic controller in a parameterized manner, supporting configuration according to the injection molding machine model, mold type or process parameters.

[0024] Specifically, the safety decision rule is stored in a parameterized form in a safety logic data area of the programmable logic controller, and the safety logic data area includes a running mode parameter, a safety input combination parameter, an action risk level parameter, and a corresponding safety response strategy parameter. Different injection molding machine models, mold types, or process parameters correspond to different parameter sets, and are managed through parameter numbers or configuration tables.

[0025] When the injection molding machine is used for production of different specifications of products or replacement of molds, the operator can select the safety parameter configuration corresponding to the current injection molding machine model, mold type, or process condition through the human-machine interface. The programmable logic controller calls the selected parameter set during operation, logically combines the collected emergency stop signal, safety door state signal, permission key signal, and current execution action, and determines the corresponding safety response strategy according to the parameterized safety decision rule.

[0026] Further, the execution action is divided into high-risk actions and low-risk actions.

[0027] Further, the high-risk actions include the mold closing action, the injection platform advancing action, and the injection action, and the low-risk actions include the ejection action and the glue melting action.

[0028] Further, the running mode includes at least a production mode and a maintenance mode, and in the maintenance mode, the execution of the high-risk actions is prohibited, and the low-risk actions are allowed to continue to be executed when the safety conditions are met.

[0029] Specifically, during the operation of the injection molding machine, the PLC identifies the type of the current execution mechanism in real time, and when the injection molding machine is in the production mode, the PLC allows the high-risk actions and the low-risk actions to be executed in accordance with the predetermined process sequence under the condition that the safety door is closed and no emergency stop signal is detected; when the safety door is opened or other safety inputs are abnormal, the PLC performs safety processing on the executing action according to the safety decision rule.

[0030] When the injection molding machine switches to the maintenance mode, the PLC automatically updates the running mode based on the permission key signal, and immediately prohibits the execution of all high-risk actions, even if the high-risk action is in the standby state, it will not be triggered. At the same time, in the maintenance mode, when the safety door is in the closed state or meets the preset safety interlocking condition, the PLC allows the low-risk actions such as the ejection action and the glue melting action to continue to be executed, so that the maintenance personnel can check the mold, clean the residual material, or debug the process.

[0031] In the maintenance mode, if the emergency stop signal is detected, the PLC still performs emergency stop control according to the highest safety level to ensure the safety of the equipment and personnel.

[0032] Further, the correspondence between the logical combination in step S2 and the safety decision rule comprises at least one combination defined in the following table:

[0034] Further, in step S3, the stop categories at least comprise:

[0035] (Section 9.2.2 of the EN60204-1 standard stipulates three stop categories: Stop Category 0: Stop by immediately cutting off the power supply to the machine equipment.

[0036] Stop Category 1: Controlled stop, the power supply to the machine equipment actuator is always kept on to make the machine equipment gradually stop. The power supply is cut off only when the machine equipment is completely stopped.

[0037] Stop Category 2: Controlled stop, the power supply to the machine equipment drive device is always kept on.

[0038] Further, when multiple safety input signals are triggered at the same time, based on the preset safety decision rule, the programmable logic controller outputs corresponding stop control instructions to the injection molding machine actuator, and the safety level priority is sorted in the order of emergency stop signal, safety door signal, and authority key signal, so that the injection molding machine performs the stop category action with the highest safety level.

[0039] In this embodiment, the programmable logic controller pre-sets the safety level priority for each type of safety input signal, wherein the safety level of the emergency stop signal is the highest, followed by the safety door status signal, and the safety level of the authority key signal is the lowest. The safety level priority is stored in the safety decision rule of the PLC in the form of parameters and participates in the safety logic combination judgment.

[0040] During the operation of the injection molding machine, when multiple safety input signals are detected to be triggered at the same time, for example, during the execution of the mold closing action, the operator opens the safety door and triggers the emergency stop button at the same time. The controller first identifies all valid safety input signals at present, and sorts and judges according to the preset safety level priority. The PLC preferentially matches the safety response strategy corresponding to the emergency stop signal with the highest safety level, and ignores the influence of the safety door signal and the authority key signal with lower safety level on the stop category.

[0041] In the above case, the PLC directly outputs an emergency stop control instruction to the injection molding machine actuator, causing the actuator to immediately execute a Stop Category 0 stop action; when the emergency stop signal is not detected, but the safety door opening and the permission key signal change are detected at the same time, the controller preferentially executes the controlled stop strategy corresponding to the safety door signal, causing the injection molding machine to execute a Stop Category 1 stop action; only when neither the emergency stop signal nor the safety door signal is triggered, the controller executes the corresponding operation mode switching or action limiting strategy according to the permission key signal.

[0042] Further, during the execution of the safety strategy, the programmable logic controller calls multiple hierarchical task blocks, including a high-priority organization block for real-time safety response, a logic processing block for operation mode switching, and a diagnostic block for log recording.

[0043] In the present embodiment, the programmable logic controller is divided into multiple hierarchical task blocks according to task priority, including a high-priority organization block for real-time safety response, a logic processing block for operation mode switching and safety logic judgment, and a diagnostic block for safety event recording and state tracing. Each task block runs at a different task level and is called periodically or event-triggered by the controller according to the preset scheduling strategy.

[0044] During the operation of the injection molding machine, when the emergency stop signal or the safety door state signal changes, the high-priority organization block is immediately triggered to quickly collect safety inputs and execute safety judgment with minimal response delay, ensuring that the emergency stop or controlled stop instruction can be issued to the actuator in the shortest time. At the same time, the logic processing block is called after the high-priority organization block completes the preliminary safety processing, for comprehensive judgment of the permission key signal, operation mode, and current execution action, and updating the corresponding safety control state.

[0045] After the safety action is executed, the diagnostic block is called to record the time of the safety event, the type of safety input, the triggered safety response strategy, and the execution result, and store the related information in the diagnostic data area of the controller or send it to the human-machine interface for display. Through the cooperative operation of the above hierarchical task blocks, the decoupling of safety response, logic processing, and information recording is realized.

[0046] Another aspect of the present application provides a programmable control system for injection molding machine safety, comprising: a safety input acquisition module for acquiring multiple safety inputs including at least an emergency stop signal, a safety door signal, and a permission key signal; A control decision module is electrically connected with the safety input acquisition module. The control decision module includes a programmable logic controller, which is configured to identify a current execution action of the injection molding machine, divide the execution action into a high-risk action and a low-risk action, determine an operation mode of the injection molding machine according to the permission key signal, and perform a logical combination judgment on the safety input signal, the current execution action and the operation mode to generate a corresponding safety response strategy. A permission level determination module is configured to determine a target operation mode based on the permission key signal, including at least a production mode, a maintenance mode and an emergency stop mode. A safety strategy storage module is configured to store safety response strategies corresponding to different safety input combinations. An actuator control module is configured to perform a full stop, a controlled speed reduction stop or selective action inhibition on the actuator according to the safety control strategy.

[0047] In embodiment 1, a programmable control method for injection molding machine safety is described by taking an electric injection molding machine using a programmable logic controller (PLC) as an example. The injection molding machine includes a mold closing mechanism, a shooting table mechanism, an injection mechanism, an ejection mechanism and corresponding servo drive units, and is equipped with an emergency stop button, a safety door switch and a permission key switch. The above signals are connected to the safety input port of the PLC.

[0048] During normal operation of the injection molding machine, step S1 is first performed. The PLC acquires multiple safety input signals in real time through the safety input acquisition module, including the trigger state of the emergency stop button, the opening or closing state of the safety door and the insertion or removal state of the permission key. Each safety input signal is acquired in a periodic scanning manner.

[0049] The PLC determines the operation mode of the injection molding machine according to the permission key signal: when the permission key is in the closed state, the system determines the production mode; when the permission key is in the open state, the system determines the maintenance mode. After determining the operation mode, the PLC further combines the current execution action state to judge the logic combination of the safety input signal.

[0050] Specifically, the PLC identifies the type of action currently being executed by the injection molding machine in real time, and distinguishes between high-risk actions and low-risk actions. Then the action type, operation mode and emergency stop signal, safety door state signal are jointly input into the pre-constructed safety logic matrix. The PLC determines the specific safety response strategy according to the logic combination result and matches the corresponding safety decision rule.

[0051] For example, when the injection molding machine is in production mode and is performing a mold closing action, if it is detected that the safety door is opened, the PLC determines that the corresponding safety response strategy of the combination is controlled shutdown according to the safety decision rule; if it is detected that the emergency stop signal is triggered in any running mode, the PLC directly determines that the safety response strategy is the highest level of emergency shutdown.

[0052] After determining the safety response strategy, the PLC outputs corresponding shutdown control instructions to the injection molding machine actuators according to the safety response strategy. When the safety response strategy is emergency shutdown, the PLC immediately cuts off the enable signal of the related servo driver, causing the injection molding machine to perform a Stop Category 0 shutdown action; when the safety response strategy is controlled shutdown, the PLC controls the servo driver to smoothly stop the actuator according to a pre-set deceleration curve, and disconnects the safety circuit after stopping; when the safety response strategy is selective inhibition action, the PLC only inhibits the continuation of high-risk actions, while allowing low-risk actions that meet safety conditions to remain running.

[0053] During the operation of the injection molding machine, the PLC first obtains the action state of each actuator in real time through the running state recognition module, including whether the mold closing mechanism is in the mold closing or mold opening stage, whether the injection table mechanism is in the forward position, whether the injection mechanism is in the injection or pressure maintaining stage, and the working state of the ejection mechanism and the glue melting mechanism. Based on the above action states, the PLC maps the current execution action as a high-risk action or a low-risk action, and uses the mapping result as an important input parameter for safety logic judgment.

[0054] The PLC then determines the current running mode based on the permission key signal. When the permission key is in the production position, the PLC determines that the injection molding machine is in production mode; when the permission key is in the maintenance position, the PLC determines that the injection molding machine is in maintenance mode. In maintenance mode, the PLC immediately sets safety inhibition flags for mold closing action, injection table forward action, and injection action, so that even if the above actions have been scheduled into the execution queue, they will not be triggered for execution, eliminating the possibility of misstarting high-risk actions from the control level.

[0055] After completing the running mode determination, the PLC inputs the emergency stop signal, the safety door state signal, the permission key signal, the current execution action type, and the running mode into the pre-constructed safety logic matrix. The safety logic matrix corresponds to the parameterized safety decision rule stored in the safety logic data area, and quickly matches the safety response strategy corresponding to the current logic combination through parameter indexing.

[0056] When the emergency stop signal is detected to be triggered, no matter what the current operation mode or the action of the injection molding machine is, the PLC immediately determines that the safety response strategy corresponding to the state is the highest level of emergency stop, and cuts off the enable signal of the related servo driver through the safety output channel, so that the injection molding machine executes the Stop Category 0 stop action; when the emergency stop signal is not detected but the safety door is opened, the PLC determines whether to execute the controlled stop strategy according to the current action type and operation mode, and issues the Stop Category 1 stop instruction to the actuator, so that each actuator stops smoothly according to the preset deceleration curve.

[0057] In the case of simultaneous triggering of multiple safety input signals, the PLC sorts and judges the safety input signals according to the preset safety level priority order, which is in turn emergency stop signal, safety door state signal and authority key signal. The PLC always gives priority to the safety response strategy corresponding to the safety input signal with the highest safety level, ensuring that the injection molding machine can quickly enter the safest state under complex abnormal scenarios.

[0058] During the execution of the safety action, the PLC calls the high-priority organization block to complete the real-time response of the safety input and the output of the stop instruction, and at the same time calls the logic processing block to update the running mode and action prohibition state, and records the safety event information after the completion of the safety action by the diagnosis block. The safety event information at least includes the safety input signal type, the triggering time, the running mode, the execution action state and the actually executed stop category, and can be queried or exported through the human-machine interface.

[0059] When the safety condition is restored, the PLC does not immediately restore all action permissions, but performs a secondary safety check on the current state of the injection molding machine. In the production mode, only when the emergency stop signal is reset, the safety door is closed and there is no unremoved safety locking condition, the PLC allows the injection molding machine to enter the runnable state; in the maintenance mode, even if the safety door is closed, the PLC still prohibits high-risk actions, until the authority key signal is switched back to the production mode and the corresponding safety confirmation process is completed.

[0060] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A programmable control method for the safety of injection molding machines, characterized in that, include: S1: Collect multiple safety input signals from the injection molding machine, including at least an emergency stop signal, a safety door status signal, and an access key signal; S2: The operating mode of the injection molding machine is determined based on the access key signal. The programmable logic controller performs logical combination judgment on the safety input signal, the current execution action and the operating mode. According to the correspondence between the pre-built logical combination and the safety decision rules, the safety response strategy in the corresponding safety decision rules is determined. S3: Based on the safety response strategy, control the injection molding machine actuator to output the corresponding stop control command, so that the injection molding machine performs the stop action with the highest safety level.

2. The control method according to claim 1, characterized in that, The safety decision rules are stored in the programmable logic controller in a parameterized manner, and can be configured according to the injection molding machine model, mold type or process parameters.

3. The control method according to claim 1, characterized in that, The actions to be performed are divided into high-risk actions and low-risk actions.

4. The control method according to claim 3, characterized in that, The high-risk actions include mold closing, injection stage forward movement, and injection, while the low-risk actions include ejection and melting.

5. The control method according to claim 1, characterized in that, The operating modes include at least a production mode and a maintenance mode. In the maintenance mode, the execution of high-risk actions is prohibited, while low-risk actions are allowed to continue to be executed when safety conditions are met.

6. The control method according to claim 1, characterized in that, in, The correspondence between the logical combinations and security decision rules in step S2 includes at least one combination as defined in the following table: 。 7. The control method according to claim 6, characterized in that, In step S3, the shutdown categories include at least: 。 8. The control method according to claim 7, characterized in that, When multiple safety input signals are triggered simultaneously, the programmable logic controller outputs a corresponding shutdown control command to the injection molding machine actuator based on preset safety decision rules. The safety level priority is sorted in the order of emergency stop signal, safety door signal, and access key signal, so that the injection molding machine executes the shutdown category action with the highest safety level.

9. The control method according to claim 8, characterized in that, During the execution of the security policy, the programmable logic controller calls multiple hierarchical task blocks, including a high-priority organization block for real-time security response, a logic processing block for switching operating modes, and a diagnostic block for logging.

10. A programmable control system for the safety of an injection molding machine, characterized in that, include: The safety input acquisition module is used to acquire multiple safety inputs, including at least emergency stop signals, safety door signals, and access key signals. The control decision module is electrically connected to the safety input acquisition module. The control decision module includes a programmable logic controller (PLC) for identifying the current execution action of the injection molding machine and classifying the execution action into high-risk actions and low-risk actions. It determines the operating mode of the injection molding machine based on the access key signal and performs logical combination judgment on the safety input signal, the current execution action, and the operating mode to generate a corresponding safety response strategy. The permission level determination module is used to determine the target operating mode based on the permission key signal, including at least production mode, maintenance mode and emergency stop mode; The security policy storage module is used to store security response policies corresponding to different combinations of security inputs. The actuator control module is used to perform full stop, controlled speed reduction stop, or selective prohibition actions on the actuator according to the safety control strategy.

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