Sand core dip-coating control system and method

Abstract

The invention relates to a sand core dip-coating control system and method.The sand core dip-coating control system comprises a visual positioning module, a main control unit, a servo driving system and a communication network, and the visual positioning module is used for obtaining actual coordinates and model information of a sand core in real time, calculating the deviation value of the actual coordinates and theoretical coordinates and sending the deviation value to the main control unit; the deviation value and the model information are transmitted to the main control unit; the main control unit is used for receiving the position deviation value and the model information of the sand core, matching the corresponding dip-coating process parameters based on the model of the sand core, establishing a coupling relationship among the dip-coating process parameters, and generating a motion control instruction; and the servo driving system comprises at least three linear shafts and at least one rotating shaft, and is used for receiving the motion control instruction of the main control unit and executing the actions of grabbing, immersing, staying and lifting the sand core. The control method is performed using a control system. The problems of paint stirring, dip-coating parameter control and motion precision can be systematically solved, and the process consistency and the product percent of pass are improved.

Description

Technical Field

[0001] This invention belongs to the field of control technology, specifically relating to a sand core impregnation and coating control system and method. Background Technology

[0002] Sand core impregnation coating is a crucial step in the casting process, aiming to improve the surface quality and refractory properties of the sand cores through coating. Traditional sand core impregnation coating control relies heavily on manual operation or semi-automated equipment, which presents the following problems:

[0003] Uneven mixing of coatings: In the prior art, although the coating mixing partially adopts mechanical circulation (such as the connection scheme between the dipping tank and the circulation mechanism proposed in patent CN202310324483), the sand core still needs to be fixed manually and hoisted before dipping, which cannot ensure the real-time uniformity of the coating composition.

[0004] Dipping depth and time depend on human experience: dipping depth, dwell time and core lifting speed all require human intervention. Differences in operation can easily lead to uneven coating thickness. For example, lifting too fast will cause uneven paint flow, while lifting too slow will cause sagging.

[0005] Low positioning accuracy: The positional deviation of manually placed sand cores is typically ±3-5mm, while traditional mechanical positioning relies on fixed trajectories and cannot be dynamically corrected. Sand core placement deviations can easily lead to gripping misalignment.

[0006] Inefficiency: Frequent manual intervention (such as the visual sensor verification of the grasping position proposed in patent CN119525445A) means that since the previous station is for manual core assembly, errors are inevitable in the position of the sand core on the tray. However, patent CN119525445A uses preset position coordinates and visual sensor verification for grasping; if the coordinates are not synchronized, an alarm is issued, causing production to be interrupted. Continuous production is difficult to achieve.

[0007] Manual placement of sand cores inevitably results in positional deviations, and existing semi-automatic systems lack real-time, high-precision visual feedback and dynamic compensation mechanisms, leading to grasping misalignment. The immersion depth, residence time, and lifting speed are interconnected (e.g., excessively fast lifting speed leads to uneven flow, while excessively slow speed causes sagging), making precise coordination difficult with human experience. Existing technologies (such as CN202310324483) have also failed to achieve automated, interconnected control of these key parameters.

[0008] The processes of paint mixing, core positioning, and dip coating are independent of each other and lack unified and efficient collaborative control. Traditional PLCs, limited by data processing capabilities and communication bandwidth, cannot meet the real-time, synchronization, and data throughput requirements of vision positioning, multi-axis servo motion, and dynamic adjustment of process parameters.

[0009] In summary, there is an urgent need to provide a sand core dip coating control system and method that can systematically solve the problems of coating mixing, dip coating parameter control and motion accuracy, and improve process consistency and product qualification rate. Summary of the Invention

[0010] The purpose of this invention is to provide a sand core dip coating control system and method that can systematically solve the problems of coating mixing, dip coating parameter control and motion accuracy, and improve process consistency and product qualification rate.

[0011] The above objective is achieved through the following technical solution: a sand core impregnation control system, comprising:

[0012] Visual positioning module: used to acquire the actual coordinates and model information of the sand core in real time, calculate the deviation value between the actual coordinates and the theoretical coordinates, and transmit the deviation value and model information to the main control unit;

[0013] Main control unit: Used to receive the sand core position deviation value and model information, and establish the coupling relationship between the dip coating process parameters based on the sand core model and the corresponding dip coating process parameters, and generate motion control commands;

[0014] Servo drive system: includes at least three linear axes and at least one rotary axis, used to receive motion control commands from the main control unit and execute actions such as gripping, immersing, holding and lifting of the sand core;

[0015] The communication network is used to realize real-time data interaction between the main control unit, the vision positioning module and the servo drive system, and to ensure the synchronization of the actions of each module.

[0016] In practical applications, the conveyor line transports the sand core to a preset vision station. The vision station requires the sand core to be roughly located in the center of the camera's field of view, with the posture deviation within a certain range. The industrial camera immediately captures the image of the sand core after being triggered, ensuring uniform and stable illumination and avoiding interference from reflections and shadows.

[0017] This invention constructs a closed-loop control chain of "perception-decision-execution" by integrating a visual positioning module, a servo drive system, and a main control unit. The visual positioning module senses the sand core's positional deviation in real time and transmits it to the main control unit. The main control unit dynamically adjusts the motion path of the servo drive system based on the deviation (compensating for positioning errors). Simultaneously, it calls upon dip-coating process parameters (such as dip depth, dwell time, and lifting speed) matched to the sand core model and establishes coupling relationships between these parameters. A communication network ensures real-time data interaction between modules, achieving closed-loop collaborative control of "positioning-motion-parameters." This solves the technical problems in traditional sand core dip-coating systems where positioning, motion control, and process parameter adjustment are independent and cannot be dynamically coordinated, leading to low positioning accuracy, uneven coating thickness (due to a lack of linkage between dip depth, time, and speed), and poor production continuity.

[0018] A further technical solution is that the main control unit has a built-in process parameter database including the dip coating process parameters. The dip coating process parameters include dip coating depth, residence time, lifting speed curve, stirring speed and rotation shaft swing angle, and the dip coating process parameters form a preset coupling logic based on the sand core model.

[0019] The "coupling logic" of this invention is the core rule for achieving coordinated control of "sand core characteristics - motion parameters - process parameters". Its essence is a multi-parameter dynamic correlation model based on sand core type, geometric features and process objectives (such as coating thickness uniformity and adhesion strength), which is stored in the process parameter database of the main control unit. It is dynamically called and adjusted through real-time data feedback (visual positioning, sensor signals). On the one hand, the initial value of the core parameters is locked by the sand core model to ensure that different sand cores are matched with the appropriate process benchmark from the beginning of dip coating. This solves the problems of insufficient coating of complex sand cores and waste of coating of simple sand cores caused by the "one-size-fits-all" parameters in traditional technology.

[0020] Thus, adaptive dip coating for different sand core types is achieved through parameter database, and parameter coupling further reduces the coating defect rate by ≥20%, solving the technical problems in the prior art where process parameters are set in isolation, cannot be adaptively adjusted according to sand core type, and there is a lack of linkage between parameters (such as uneven coating caused by mismatch between lifting speed and rotation angle).

[0021] A further technical solution is that the sand core impregnation control system also includes a stirring execution module, which includes a variable frequency stirring motor and a driver. The driver is connected to the main control unit through the communication network and receives and executes the stirring start command and speed command generated by the main control unit.

[0022] Based on the position signal fed back by the servo drive system, the stirring execution module is automatically triggered to ensure that the coating is in a uniform state during dip coating. In traditional systems, the stirring module is controlled independently of the dip coating process, and the coating is prone to sedimentation during deep immersion, resulting in uneven composition and affecting the coating quality. In this invention, the stirring execution module acts as the execution unit of the control system, receiving linkage commands from the main control unit to execute the stirring action.

[0023] A further technical solution is that the sand core immersion coating control system also includes a liquid level sensor for detecting the coating height in the immersion tank. The liquid level sensor is communicatively connected to the main control unit and transmits the detection data to the main control unit. The immersion depth is confirmed by the servo position, and whether immersion coating is complete is determined by the immersion parameters. The liquid level sensor detects the coating height in the immersion tank. If the liquid level is insufficient, it is automatically replenished. Three sensors are set: minimum liquid level, replenishment liquid level, and maximum liquid level. The replenishment liquid level enables automatic coating replenishment, the minimum liquid level triggers an alarm, and the maximum liquid level controls and stops replenishment.

[0024] To achieve the above objectives, the present invention also provides a method for controlling the impregnation coating of sand cores, which is executed using any of the sand core impregnation coating control systems described above, and includes the following steps:

[0025] S1. Trigger the visual positioning module to obtain the actual coordinates and model information of the sand core, and calculate the deviation between the actual coordinates and the theoretical coordinates;

[0026] S2. The main control unit generates a compensation motion path for the servo drive system based on the deviation value, and calls the corresponding dip coating process parameters based on the sand core model, establishes the coupling relationship between the dip coating process parameters and the linkage relationship between the parameters and the motion path, and sends the compensation motion path command and process parameter execution command to the controller and the stirring execution module.

[0027] S3. The servo drive system receives the instruction, grabs the sand core according to the compensated motion path, moves it to the dip coating tank, and performs immersion, dwell and lifting actions according to the dip coating process parameters. At the same time, the main control unit controls the stirring execution module mechanism to run in advance before the dip coating action.

[0028] S4. After completing the dip coating, record the process data and upload it to the management system for quality traceability and parameter library optimization.

[0029] This invention obtains positioning deviation in real time through step S1, dynamically generates compensation path and binds parameter coupling relationship through step S2, realizes the coordination of dip coating, stirring and lifting through step S3, and completes data traceability and optimization through step S4. The entire process eliminates manual intervention, improves coating qualification rate and reduces production interruption rate.

[0030] A further technical solution is that, in step S2, the main control unit synchronously sends the compensation motion path instruction and process parameter execution instruction to the servo drive system and the stirring execution module via a communication network. After receiving the instruction, the stirring execution module starts and accelerates to the initial speed set by the coupling relationship at a predetermined time to ensure that the coating is in a uniform state when the sand core is immersed.

[0031] The communication network ensures that the instruction transmission delay is ≤10ms and the time difference between each device receiving instructions is ≤1μs, avoiding misalignment of actions due to asynchronous instructions. Stirring needs to be pre-started. In non-continuous production, it is set to accelerate to a set high speed, then decelerate to a set low speed after a delay. The servo stops when it reaches the designated position until the dip coating is complete. The initial process for continuous production is the same as above; thereafter, it remains stationary during dip coating without stirring, and operates at low speed when not dip coated.

[0032] A further technical solution is that, in step S3, the servo drive system transports the sand core to the top of the immersion tank according to the compensation path, and the Z-axis encoder provides real-time feedback of position information: the Z-axis sinking speed of the servo drive system is related to the rotation axis angle, and when the Z-axis position approaches the immersion depth threshold, the main control unit triggers a deceleration command, and the servo drive system performs deceleration to avoid overshoot due to inertia; when the servo drive system controls the sand core immersion depth to reach the preset depth, the Z-axis of the servo drive system immediately stops; the servo drive system and the stirring execution module perform related actions based on the coupling logic preset by the main control unit.

[0033] This invention employs a collaborative immersion scheme, in which the sand core is steadily immersed into the coating pool along a planned path (usually descending along the Z-axis and adjusting the posture with the rotation axis) until a preset depth is reached. This ensures that the sand core is close to the liquid surface and that the immersion speed is precisely controlled in the initial stage to prevent splashing or the intake of air bubbles.

[0034] A further technical solution is that, in step S3, after the dwell time ends, the main control unit sends a lifting command to the servo drive system and executes it according to a preset lifting speed curve. The lifting speed curve is a segmented lifting speed curve, in which the initial segment of the segmented lifting speed curve is lower than the middle segment's lifting speed, and the middle segment's lifting speed is lower than the final segment's lifting speed. This ensures that the sand core is lifted out of the coating pool smoothly while removing it from the liquid surface to reduce the flow of surface coating.

[0035] This invention utilizes a segmented nonlinear velocity curve. The initial segment is slow to reduce the inertial flow of the coating, the middle segment is accelerated to avoid sagging, and the final segment is rapidly improved to increase efficiency, thereby controlling the coating thickness deviation to ≤0.05mm.

[0036] A further technical solution is to set a velocity abrupt change point at the liquid surface in the segmented lifting velocity curve, and the acceleration of the velocity abrupt change point is smoothed by curve processing. This setting solves the problem of fluid splashing during the lifting process.

[0037] A further technical solution is that the sand core dipping control system also includes a viscosity detection mechanism. This mechanism detects the viscosity of the dipping solution and is communicatively connected to the main control unit, transmitting the detection data to the main control unit. The main control unit then controls the stirring execution module based on the detection results. Specifically, when an increase in viscosity is detected, the rotation speed can be slightly increased, but not excessively. An upper limit needs to be set according to the actual situation to ensure that the coating viscosity fluctuation rate is ≤5%, thereby improving the coating adhesion quality.

[0038] Compared to existing technologies, the implementation of this invention breaks through the limitations of "isolated parameter setting" in traditional technologies. It constructs a full-link correlation of "sand core characteristics - working conditions - process parameters - motion parameters," realizing a leap from "human experience-driven" to "high-precision, high-coordination, and self-optimizing" intelligent control in sand core impregnation coating. It systematically solves the core problems in traditional sand core impregnation coating processes, such as low positioning accuracy, poor parameter coordination, insufficient production continuity, and poor coating uniformity. At least the following effects are included:

[0039] 1. Breakthrough improvement in positioning accuracy and dynamic compensation capability: Through the high-precision coordinate recognition of the visual positioning module and the real-time compensation algorithm of the main control unit, the problem of "manual core assembly position error causing grasping offset" is solved, ensuring that the trajectory deviation of sand core grasping, immersion and lifting is controlled at the sub-millimeter level, laying the foundation for coating uniformity;

[0040] 2. High coating quality achieved through coupled process parameter control: Relying on the coupled model of "sand core type - immersion depth - residence time - lifting speed - stirring speed" built into the main control unit, the limitations of traditional isolated parameter control are broken through, thereby improving the coating quality of sand cores. Attached Figure Description

[0041] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0042] Figure 1 This is a structural block diagram of a sand core impregnation control system according to one embodiment of the present invention;

[0043] Figure 2 This is a schematic flowchart of a sand core impregnation control method according to one embodiment of the present invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings. This description is merely illustrative and explanatory, and should not be construed as limiting the scope of protection of the present invention. Furthermore, those skilled in the art can combine the features in the embodiments described herein and in different embodiments accordingly based on the description in this document.

[0045] The embodiments of the present invention are as follows, with reference to Figure 1 A sand core impregnation control system, comprising:

[0046] Visual positioning module: used to acquire the actual coordinates and model information of the sand core in real time, calculate the deviation value between the actual coordinates and the theoretical coordinates, and transmit the deviation value and model information to the main control unit;

[0047] Main control unit: Used to receive the sand core position deviation value and model information, and establish the coupling relationship between the dip coating process parameters based on the sand core model and the corresponding dip coating process parameters, and generate motion control commands;

[0048] Servo drive system: includes at least three linear axes and at least one rotary axis, used to receive motion control commands from the main control unit and execute actions such as gripping, immersing, holding and lifting of the sand core;

[0049] The communication network is used to realize real-time data interaction between the main control unit, the vision positioning module and the servo drive system, and to ensure the synchronization of the actions of each module.

[0050] In practical applications, the conveyor line transports the sand core to a preset vision station. The vision station requires the sand core to be roughly located in the center of the camera's field of view, with the posture deviation within a certain range. The industrial camera immediately captures the image of the sand core after being triggered, ensuring uniform and stable illumination and avoiding interference from reflections and shadows.

[0051] This invention constructs a closed-loop control chain of "perception-decision-execution" by integrating a visual positioning module, a servo drive system, and a main control unit. The visual positioning module senses the sand core's positional deviation in real time and transmits it to the main control unit. The main control unit dynamically adjusts the motion path of the servo drive system based on the deviation (compensating for positioning errors). Simultaneously, it calls upon dip-coating process parameters (such as dip depth, dwell time, and lifting speed) matched to the sand core model and establishes coupling relationships between these parameters. A communication network ensures real-time data interaction between modules, achieving closed-loop collaborative control of "positioning-motion-parameters." This solves the technical problems in traditional sand core dip-coating systems where positioning, motion control, and process parameter adjustment are independent and cannot be dynamically coordinated, leading to low positioning accuracy, uneven coating thickness (due to a lack of linkage between dip depth, time, and speed), and poor production continuity.

[0052] In one embodiment: the main control unit is a Siemens S7-1500 series PLC; utilizing the high-speed data processing capability and Profinet communication function of the Siemens S7-1500 series PLC, microsecond-level synchronous response of each module is achieved (response delay ≤10ms), ensuring efficient collaboration of the "perception-decision-execution" closed loop. The servo drive system includes a Siemens SINAMICSV90 servo driver and a matching 1FL6 servo motor; the servo system supports ±0.01mm positioning accuracy and 1kHz dynamic response, accurately executing the coating depth (deviation ≤0.1mm) and lifting speed curve (non-linear adjustment error ≤2%), reducing coating dripping or sagging. The vision system uses a Basler ace 2 series industrial camera (high resolution, global shutter) + matching industrial lens and ring light source. Key: the camera must be precisely mounted on a fixed bracket above the gripping station, and rigorous camera calibration must be performed (establishing a precise mapping relationship between the pixel coordinate system and the machine coordinate system; calibration accuracy directly affects positioning accuracy). The communication network is Profinet IRT industrial Ethernet; Profinet IRT achieves deterministic communication (jitter ≤1μs), ensuring real-time interaction of visual deviation data, servo commands, and process parameters, and guaranteeing strict synchronization between multi-axis motion and process timing. Actuator: Customized gantry frame + rotary head mechanism (X / Y / Z linear axes + rotary axis), equipped with an adaptive sand core clamp at the end. Human-Machine Interface (HMI): Integrated into the PLC system for setting process parameters (such as immersion time and speed) and monitoring status.

[0053] Software configuration:

[0054] Development environment: TIA Portal V17 (or later).

[0055] PLC Programming: STEP 7 Professional (used for writing PLC control logic, motion control programs, communication configuration, and process database management).

[0056] HMI design: WinCC Professional (for process parameter setting, status monitoring, alarm display, and data logging).

[0057] Vision processing: Vision processing software developed using custom algorithms such as Halcon, OpenCV, or Basler Pylon+ communicates with the PLC via Profinet to ensure that the vision processing cycle is strictly synchronized with the PLC scanning cycle and motion control cycle.

[0058] Motion control library: Use Siemens Technology Objects (TOs) such as Positioning Axis and Synchronous Operation to implement multi-axis coordinated motion.

[0059] The working process in one embodiment:

[0060] 1. Core feeding and initial positioning:

[0061] The conveyor line transports the sand core to a pre-set vision station. The sand core must be roughly located in the center of the camera's field of view, with its orientation deviation within a certain range.

[0062] The photoelectric sensor detects that the sand core is in place, triggering the vision system.

[0063] 2. Visual recognition and coordinate acquisition:

[0064] The industrial camera captures the image of the sand core immediately after being triggered. It is necessary to ensure uniform and stable lighting and avoid interference from reflections and shadows.

[0065] The vision software uses a preset image processing algorithm to accurately extract the center point coordinates and principal axis angle of the sand core.

[0066] By calibrating the transformation matrix, the image pixel coordinates (u,v,θ) are converted into actual coordinates (X_m,Y_m,Z_ref,θ_m) in the base coordinate system in real time and with high precision. Here, Z_ref is the preset grab height reference plane.

[0067] The vision system transmits (ΔX, ΔY, Δθ) (i.e., the deviation between the actual coordinates and the theoretical grasping coordinates) to the PLC at high speed and with low latency through Profinet IRT.

[0068] 3. PLC dynamic path planning and parameter binding:

[0069] The PLC receives visual deviation data (ΔX, ΔY, Δθ).

[0070] Dynamic compensation calculation: The PLC's motion control module combines the current position, the theoretical coordinates (X_t, Y_t, Z_t, θ_t) of the target grasping point, and the visual deviation (ΔX, ΔY, Δθ) to calculate the compensated motion path required for the end effector of the servo system to reach the precise grasping point.

[0071] Process parameter matching: Based on the initial visual identification of the sand core model, the PLC automatically retrieves and binds the optimal dipping parameters corresponding to that model from its built-in process parameter database.

[0072] Z_immersion: Target immersion depth.

[0073] T_dwell: Dwell time after dip coating.

[0074] V_lift: Lifting speed (mm / s, usually a variable speed curve, such as initial slow lift off the liquid surface, followed by accelerated lift).

[0075] Stir_Speed: The corresponding stirring speed.

[0076] Rotation_Angle: The oscillation angle / speed of the rotating shaft during the dip coating process (used for complex sand cores).

[0077] Path fusion: The PLC integrates the compensated grab path, immersion path, dwell action, and lifting path (according to the V_lift speed curve) into a complete and smooth coordinated motion trajectory.

[0078] The PLC uses Profinet IRT to send the calculated trajectory points, speed commands, and synchronization points to each servo drive in real time.

[0079] Servo execution and dip coating process:

[0080] The servo system strictly follows the instructions issued by the PLC to drive the servo mechanism:

[0081] Precise gripping: First, move quickly and accurately to the compensated gripping point (X_t+ΔX,Y_t+ΔY,Z_t,θ_t+Δθ), and the clamp closes to grip the sand core.

[0082] Synergistic Immersion: The sand core is smoothly immersed into the coating tank along the planned path (usually descending along the Z-axis, combined with adjusting the attitude along the rotation axis) until the preset depth Z_immersion is reached. Key points: The speed must be precisely controlled when approaching the liquid surface and in the initial immersion stage to prevent splashing or air bubbles from being drawn in.

[0083] Precise Dwell: Maintain a precise T_dwell second at the immersion depth to ensure full coating wetting. During this time, the stirring mechanism continues to run at the bound Stir_Speed ​​to maintain coating uniformity.

[0084] Controlled lifting: The sand core is smoothly lifted out of the coating tank according to the speed curve defined by V_lift (usually non-linear, e.g., an initial slow speed of V_slow to remove the core from the liquid surface to reduce flow, then accelerated to V_fast to lift it to a high position). Precise control of the lifting speed is the most critical factor in ensuring the uniformity of the coating thickness.

[0085] 4. Completion and Data Management:

[0086] After the sand core is raised to a safe position, the sensor confirms that the dipping coating is complete.

[0087] The servo mechanism moves the sand core to the draining or next process position.

[0088] The PLC records complete process data for this operation: core type, visual deviation value, actual immersion depth, actual dwell time, key points of the actual lifting speed curve, timestamp, etc.

[0089] The data is uploaded to the MES system via a communication interface for quality traceability and production analysis.

[0090] A further technical solution is that the main control unit has a built-in process parameter database including the dip coating process parameters. The dip coating process parameters include dip coating depth, residence time, lifting speed curve, stirring speed and rotation shaft swing angle, and the dip coating process parameters form a preset coupling logic based on the sand core model.

[0091] The "coupling logic" of this invention is the core rule for achieving coordinated control of "sand core characteristics - motion parameters - process parameters". Its essence is a multi-parameter dynamic correlation model based on sand core type, geometric features and process objectives (such as coating thickness uniformity and adhesion strength), which is stored in the process parameter database of the main control unit. It is dynamically called and adjusted through real-time data feedback (visual positioning, sensor signals). On the one hand, the initial value of the core parameters is locked by the sand core model to ensure that different sand cores are matched with the appropriate process benchmark from the beginning of dip coating. This solves the problems of insufficient coating of complex sand cores and waste of coating of simple sand cores caused by the "one-size-fits-all" parameters in traditional technology.

[0092] Thus, adaptive dip coating for different sand core types is achieved through parameter database, and parameter coupling further reduces the coating defect rate by ≥20%, solving the technical problems in the prior art where process parameters are set in isolation, cannot be adaptively adjusted according to sand core type, and there is a lack of linkage between parameters (such as uneven coating caused by mismatch between lifting speed and rotation angle).

[0093] Based on the above embodiments, in another embodiment of the present invention, the sand core impregnation control system further includes a stirring execution module, which includes a variable frequency stirring motor and a driver. The driver is connected to the main control unit through the communication network and receives and executes the stirring start command and speed command generated by the main control unit.

[0094] Based on the position signal fed back by the servo drive system, the stirring execution module is automatically triggered to ensure that the coating is in a uniform state during dip coating. In traditional systems, the stirring module is controlled independently of the dip coating process, and the coating is prone to sedimentation during deep immersion, resulting in uneven composition and affecting the coating quality. In this invention, the stirring execution module acts as the execution unit of the control system, receiving linkage commands from the main control unit to execute the stirring action.

[0095] Based on the above embodiments, in another embodiment of the present invention, the sand core immersion coating control system further includes a liquid level sensor for detecting the coating height in the immersion tank. The liquid level sensor is communicatively connected to the main control unit and transmits the detection data to the main control unit. The immersion depth is confirmed by the servo position, and whether immersion coating is complete is determined by the immersion parameters. The liquid level sensor detects the coating height in the immersion tank. If the liquid level is insufficient, it is automatically replenished. Three sensors are set: minimum liquid level, replenishment liquid level, and maximum liquid level. The replenishment liquid level enables automatic coating replenishment, the minimum liquid level triggers an alarm, and the maximum liquid level controls and stops replenishment. The present invention also provides a sand core immersion coating control method, the embodiment of which is as follows. Figure 2 The process, performed using any of the aforementioned sand core impregnation control systems, includes the following steps:

[0096] S1. Trigger the visual positioning module to obtain the actual coordinates and model information of the sand core, and calculate the deviation between the actual coordinates and the theoretical coordinates;

[0097] S2. The main control unit generates a compensation motion path for the servo drive system based on the deviation value, and calls the corresponding dip coating process parameters based on the sand core model, establishes the coupling relationship between the dip coating process parameters and the linkage relationship between the parameters and the motion path, and sends the compensation motion path command and process parameter execution command to the controller and the stirring execution module.

[0098] S3. The servo drive system receives the instruction, grabs the sand core according to the compensated motion path, moves it to the dip coating tank, and performs immersion, dwell and lifting actions according to the dip coating process parameters. At the same time, the main control unit controls the stirring execution module mechanism to run in advance before the dip coating action.

[0099] S4. After completing the dip coating, record the process data and upload it to the management system for quality traceability and parameter library optimization.

[0100] This invention obtains positioning deviation in real time through step S1, dynamically generates compensation path and binds parameter coupling relationship through step S2, realizes the coordination of dip coating, stirring and lifting through step S3, and completes data traceability and optimization through step S4. The entire process eliminates manual intervention, improves coating qualification rate and reduces production interruption rate.

[0101] Based on the above embodiments, in another embodiment of the present invention, in step S2, the main control unit synchronously sends the compensation motion path instruction and process parameter execution instruction to the servo drive system and the stirring execution module via a communication network. After receiving the instruction, the stirring execution module starts and accelerates to the initial speed set by the coupling relationship at a predetermined time to ensure that the coating is in a uniform state when the sand core is immersed.

[0102] The communication network ensures that the instruction transmission delay is ≤10ms and the time difference between each device receiving instructions is ≤1μs, avoiding misalignment of actions due to asynchronous instructions. Stirring needs to be pre-started. In non-continuous production, it is set to accelerate to a set high speed, then decelerate to a set low speed after a delay. The servo stops when it reaches the designated position until the dip coating is complete. The initial process for continuous production is the same as above; thereafter, it remains stationary during dip coating without stirring, and operates at low speed when not dip coated.

[0103] Based on the above embodiments, in another embodiment of the present invention, in step S3, the servo drive system transports the sand core to the top of the immersion tank according to the compensation path, and the Z-axis encoder provides real-time feedback of position information: the Z-axis sinking speed of the servo drive system is related to the rotation axis angle, and when the Z-axis position is close to the immersion depth threshold, the main control unit triggers a deceleration command, and the servo drive system performs deceleration to avoid overshoot due to inertia; when the servo drive system controls the sand core immersion depth to reach the preset depth, the Z-axis of the servo drive system stops immediately; the servo drive system and the stirring execution module perform related actions based on the coupling logic preset by the main control unit.

[0104] This invention employs a collaborative immersion scheme, in which the sand core is steadily immersed into the coating pool along a planned path (usually descending along the Z-axis and adjusting the posture with the rotation axis) until a preset depth is reached. This ensures that the sand core is close to the liquid surface and that the immersion speed is precisely controlled in the initial stage to prevent splashing or the intake of air bubbles.

[0105] Based on the above embodiments, in another embodiment of the present invention, in step S3, after the dwell time ends, the main control unit sends a lifting command to the servo drive system and executes it according to a preset lifting speed curve. The lifting speed curve is a segmented lifting speed curve. The initial segment of the segmented lifting speed curve is lower than the lifting speed of the middle segment, and the lifting speed of the middle segment is lower than the lifting speed of the final segment. This ensures that the sand core is lifted out of the coating pool smoothly while removing it from the liquid surface to reduce the flow of surface coating.

[0106] This invention utilizes a segmented nonlinear velocity curve. The initial segment is slow to reduce the inertial flow of the coating, the middle segment is accelerated to avoid sagging, and the final segment is rapidly improved to increase efficiency, thereby controlling the coating thickness deviation to ≤0.05mm.

[0107] In one specific embodiment, the initial speed of the lifting speed curve V is 2-5 mm / s, the middle speed is 8-15 mm / s, and the final speed is 15-20 mm / s. In the initial segment, the adhesion of the coating on the sand core surface is sensed through Z-axis torque feedback. If the torque is abnormal (such as the coating being too thick, causing a sudden increase in resistance), the speed is temporarily reduced to 1 mm / s to reduce coating tearing. In the middle segment, the stirring mechanism is simultaneously shut off (to avoid coating splashing), and the rotating shaft is reset to the initial angle. In the final segment, the speed is accelerated to detach from the coating liquid surface, and the air blowing device (the airflow intensity is linked to the lifting speed) is activated to remove excess coating.

[0108] Based on the above embodiments, in another embodiment of the present invention, the segmented lifting speed curve has a speed abrupt change point at the liquid surface, and the acceleration of the speed abrupt change point is smoothed by curve processing. This setting solves the problem of fluid splashing during the lifting process.

[0109] Based on the above embodiments, in another embodiment of the present invention, the sand core dipping control system further includes a viscosity detection mechanism. This mechanism detects the viscosity of the dipping solution and is communicatively connected to the main control unit, transmitting the detection data to the main control unit. The main control unit then controls the stirring execution module based on the detection results. Specifically, when an increase in viscosity is detected, the rotation speed can be slightly increased, but not excessively. An upper limit needs to be set according to the actual situation to ensure that the coating viscosity fluctuation rate is ≤5%, thereby improving the coating adhesion quality.

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A sand core impregnation control system, characterized in that, include: Visual positioning module: used to acquire the actual coordinates and model information of the sand core in real time, calculate the deviation value between the actual coordinates and the theoretical coordinates, and transmit the deviation value and model information to the main control unit; Main control unit: Used to receive the sand core position deviation value and model information, and establish the coupling relationship between the dip coating process parameters based on the sand core model and the corresponding dip coating process parameters, and generate motion control commands; Servo drive system: includes at least three linear axes and at least one rotary axis, used to receive motion control commands from the main control unit and execute actions such as gripping, immersing, holding and lifting of the sand core; The communication network is used to realize real-time data interaction between the main control unit, the vision positioning module and the servo drive system, and to ensure the synchronization of the actions of each module.

2. The sand core impregnation control system according to claim 1, characterized in that, The main control unit has a built-in process parameter database that includes the dip coating process parameters. The dip coating process parameters include dip coating depth, residence time, lifting speed curve, stirring speed and rotation shaft swing angle. The dip coating process parameters form a preset coupling logic based on the sand core model.

3. The sand core impregnation control system according to claim 2, characterized in that, The sand core impregnation control system also includes a stirring execution module, which includes a variable frequency stirring motor and a driver. The driver is connected to the main control unit through the communication network and receives and executes the stirring start command and speed command generated by the main control unit.

4. The sand core impregnation control system according to any one of claims 1 to 3, characterized in that, The aforementioned sand core immersion coating control system also includes a liquid level sensor for detecting the coating height in the immersion tank. The liquid level sensor is communicatively connected to the main control unit and transmits the detection data to the main control unit.

5. A method for controlling the impregnation coating of sand cores, characterized in that, The process, performed using the sand core impregnation control system according to any one of claims 1 to 4, includes the following steps: S1. Trigger the visual positioning module to obtain the actual coordinates and model information of the sand core, and calculate the deviation between the actual coordinates and the theoretical coordinates; S2. The main control unit generates a compensation motion path for the servo drive system based on the deviation value, and calls the corresponding dip coating process parameters based on the sand core model, establishes the coupling relationship between the dip coating process parameters and the linkage relationship between the parameters and the motion path, and sends the compensation motion path command and process parameter execution command to the controller and the stirring execution module. S3. The servo drive system receives the instruction, grabs the sand core according to the compensated motion path, moves it to the dip coating tank, and performs immersion, dwell and lifting actions according to the dip coating process parameters. At the same time, the main control unit controls the stirring execution module mechanism to run in advance before the dip coating action. S4. After completing the dip coating, record the process data and upload it to the management system for quality traceability and parameter library optimization.

6. The method for controlling the impregnation coating of sand cores according to claim 5, characterized in that, In step S2, the main control unit synchronously sends the compensation motion path command and process parameter execution command to the servo drive system and the stirring execution module via the communication network. After receiving the command, the stirring execution module starts and accelerates to the initial speed set by the coupling relationship at a predetermined time to ensure that the coating is in a uniform state when the sand core is immersed.

7. The method for controlling the impregnation coating of sand cores according to claim 5, characterized in that, In step S3, the servo drive system transports the sand core to the top of the immersion tank according to the compensation path, and provides real-time position information through the Z-axis encoder: the sinking speed of the Z-axis of the servo drive system is related to the rotation axis angle, and when the Z-axis position is close to the immersion depth threshold, the main control unit triggers a deceleration command, and the servo drive system performs deceleration to avoid overshoot due to inertia; when the immersion depth of the sand core reaches the preset depth, the Z-axis of the servo drive system stops immediately; the servo drive system and the stirring execution module perform related actions based on the coupling logic preset by the main control unit.

8. The method for controlling the impregnation coating of sand cores according to claim 5, characterized in that, In step S3, after the dwell time ends, the main control unit sends a lifting command to the servo drive system and executes it according to the preset lifting speed curve. The lifting speed curve is a segmented lifting speed curve. The initial segment of the segmented lifting speed curve is lower than the lifting speed of the middle segment, and the lifting speed of the middle segment is lower than the lifting speed of the final segment. This ensures that the sand core is lifted out of the coating pool while removing it from the liquid surface to reduce the flow of surface coating.

9. The method for controlling the impregnation coating of sand cores according to claim 8, characterized in that, The segmented lifting speed curve has a speed change point at the liquid surface, and the acceleration at the speed change point is smoothed by curve processing.

10. The method for controlling the impregnation coating of sand cores according to claim 9, characterized in that, The sand core impregnation control system also includes a viscosity detection mechanism, which is used to detect the viscosity of the impregnation solution. The viscosity detection mechanism is communicatively connected to the main control unit and transmits the detection data to the main control unit. The main control unit controls the stirring execution module to operate based on the detection results.

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