Automatic paint adding system for electrophoretic coating line

Abstract

The invention discloses an automatic paint adding system for an electrophoretic coating line, and relates to the technical field of electrophoretic coating production, the automatic paint adding system comprises a current acquisition unit, and the current acquisition unit is configured to acquire a current signal flowing through an electrophoretic workpiece in real time; and the electric quantity calculation unit is in communication connection with the current acquisition unit, and the electric quantity calculation unit is configured to perform integral operation on the current signal. According to the invention, through accurate current tracking and closed-loop weight control, it is ensured that color paste and emulsion are synchronously added according to needs, the stability of bath solution components is ensured from the source, and the quality consistency of a coating is remarkably improved; a batch adding strategy is matched with an automatic pipeline cleaning function, so that the loss caused by frequent start and stop of equipment is reduced, pipeline residues and tank liquid fluctuation are effectively prevented, the reliability of the system is improved, and the maintenance cost is reduced; the whole-process data recording function provides accurate data support for production cost accounting and process optimization, and the traceability of quality problems is realized.

Description

Technical Field

[0001] This application relates to the field of electrophoretic coating production technology, and in particular to an automatic paint application system for an electrophoretic coating line. Background Technology

[0002] In the field of electrophoretic coating production, the stability and consistency of coating quality are the core lifeline, which is closely related to the long-term stability of the paint composition in the electrophoretic tank. However, the paint replenishment methods commonly used in the industry still have significant defects, seriously restricting further improvement of product quality and refined control of production costs. Traditional paint replenishment operations rely heavily on manual experience, usually adding paint at fixed times and in fixed quantities based on preset production shifts or rough output estimates. This extensive management method has inherent lag and cannot match the actual paint consumption caused by the real-time changes in the number of workpieces, surface area, and complex shapes on the production line, which easily leads to fluctuations in the composition of the tank solution. Specifically, when the paint is not added in time, the concentration of effective components in the tank solution will decrease, resulting in quality problems such as thin paint film and insufficient hiding power; while excessive addition will result in cost waste and may lead to defects such as excessively thick paint film and orange peel due to excessive concentration. In addition, frequent starting of the addition pump for small-batch replenishment, while reducing the impact of a single addition to some extent, will lead to increased wear on the pump, valves and other actuators, shortening the equipment life. At the same time, it will cause the tank solution level and concentration to fluctuate continuously in small amounts, which is not conducive to stable film formation. Due to the different characteristics of pigment paste and emulsion in the electrophoretic deposition process, their consumption rates are not strictly synchronized. Manual operation makes it difficult to achieve precise, on-demand and proportional synergistic addition of the two materials, which further exacerbates the risk of tank solution imbalance. Summary of the Invention

[0003] To address the aforementioned problems, this application provides an automatic paint application system for an electrophoretic coating line. This application provides an automatic paint application system for an electrophoretic coating line, which adopts the following technical solution: An automatic paint application system for an electrophoretic coating line includes: A current acquisition unit is configured to acquire the current signal flowing through the electrophoresis workpiece in real time; A power calculation unit is communicatively connected to the current acquisition unit. The power calculation unit is configured to perform integral calculation on the current signal to obtain the cumulative power consumption value. The paint consumption mapping unit has a pre-stored mapping relationship and adjustment coefficient between the consumption of electrophoretic paint and the power consumption. The paint consumption mapping unit is communicatively connected to the power calculation unit. The paint consumption mapping unit is configured to calculate the first actual consumption of the pigment and the second actual consumption of the emulsion based on the cumulative power consumption value. A decision-making unit is added, which is communicatively connected to the paint consumption mapping unit. A pumping execution unit, which is communicatively connected to the adding decision unit, includes a first paint adding pump for conveying pigment and a second paint adding pump for conveying emulsion; A weight measuring unit is provided on the output path of the first paint pump and the second paint pump. The weight measuring unit is configured to measure the weight of the added pigment or emulsion in real time and generate a weight signal. A closed-loop control unit is communicatively connected to the weight metering unit and the pumping execution unit. The closed-loop control unit is configured to receive a weight signal and compare the weight signal with a preset target addition amount. When the weight signal indicates that the added weight has reached the target addition amount, a stop command is issued to the pumping execution unit. As a preferred technical solution of this application, the addition decision unit is configured with a first addition threshold corresponding to the first actual consumption and a second addition threshold corresponding to the second actual consumption. The addition decision unit is configured to generate a first addition instruction when the first actual consumption reaches the first addition threshold, and to generate a second addition instruction when the second actual consumption reaches the second addition threshold. As a preferred technical solution of this application, the output end of the addition decision unit is communicatively connected to a pipeline cleaning unit, and the pipeline cleaning unit is configured to automatically execute a cleaning program after the pumping execution unit completes an addition operation and receives a stop command. As a preferred technical solution of this application, the current acquisition unit reads current data by coupling with the communication interface of the production line main control PLC. As a preferred technical solution of this application, the pre-stored mapping relationship in the paint consumption mapping unit is a linear relationship, and the paint consumption M = k × Q, where k is an adjustment coefficient and Q is the cumulative power consumption value. As a preferred technical solution of this application, both the first paint pump and the second paint pump are pneumatic diaphragm pumps. As a preferred technical solution of this application, the output terminal of the closed-loop control unit is communicatively connected to an alarm unit, which is configured to trigger an audible and visual alarm when the weight signal fed back by the weight measuring unit does not reach the target addition amount within a preset time. As a preferred technical solution of this application, the output terminals of the power calculation unit, the paint consumption mapping unit and the weight measurement unit are all communicatively connected to a data storage and display unit. The data storage and display unit is configured to record and display the cumulative power consumption, paint consumption and addition data in real time. As a preferred technical solution of this application, the weight measuring unit is a high-precision electronic scale. In summary, this application includes at least one of the following beneficial technical effects of an automatic paint application system for electrophoretic coating lines: This application ensures the synchronous addition of pigments and emulsions as needed through precise current tracking and closed-loop weight control, guaranteeing the stability of the bath composition from the source and significantly improving the consistency of coating quality. The batch addition strategy, combined with the automatic pipeline cleaning function, reduces the losses from frequent equipment start-ups and shutdowns, effectively prevents pipeline residues and bath fluctuations, improves system reliability, and reduces maintenance costs. The full-process data recording function provides accurate data support for production cost accounting and process optimization, and enables traceability of quality issues. This system comprehensively improves the level of refined and automated management of electrophoretic coating. Attached Figure Description Figure 1 This is the architecture diagram of the automatic paint application system for the electrophoretic coating line in this application. Detailed Implementation The following is in conjunction with the appendix Figure 1 This application will be described in further detail. See Figure 1 An automatic paint application system for an electrophoretic coating line includes: A current acquisition unit is configured to acquire the current signal flowing through the electrophoresis workpiece in real time. The power calculation unit is communicatively connected to the current acquisition unit. The power calculation unit is configured to perform integral calculation on the current signal to obtain the cumulative power consumption value. As the sensing starting point of the system, the accuracy and real-time performance of the current acquisition unit are the cornerstone of the reliable operation of the entire painting system. In this system, the current acquisition unit is coupled to the main control PLC of the production line through a communication interface. Specifically, it utilizes industry-standard communication protocols (such as Modbus TCP / IP, PROFINET, etc.) to directly read the real-time current signal flowing through the workpiece from the PLC controlling the electrophoresis power supply or the main circuit of the electrophoresis tank. This method avoids the accuracy errors, installation inconvenience, and invasive modifications to the existing production line that might result from additional sensor installations, ensuring a high degree of data consistency with the original system. The read current signal is a high-frequency sampled instantaneous value, capable of accurately capturing minute changes caused by complex workpiece shapes and current fluctuations during the entry and exit stages of the coating tank. After receiving continuous current-time series data from the current acquisition unit, the core task of the power consumption calculation unit is to perform precise integration calculations, converting the fluctuating current signal over time into a cumulative power consumption value (unit: ampere-hour, Ah). In terms of software implementation, this unit uses a high-performance embedded processor or industrial PC running a real-time operating system. Its algorithm is not a simple periodic accumulation, but employs numerical integration methods such as the trapezoidal integral method to calculate the area under the current curve with higher accuracy. For example, the system samples the current value 100 times per second. Within each sampling period, the current value is averaged with the current value of the previous period, multiplied by the time interval, to obtain the power consumption for that small time period, which is then accumulated. The advantage of this method is its ability to smoothly handle rapid current fluctuations, calculating a more accurate power consumption value closer to the theoretical value. The cumulative power consumption value is updated at a high frequency (e.g., once per second) and sent to subsequent units, providing a solid and dynamic data foundation for the accurate mapping of paint consumption. The paint consumption mapping unit has a pre-stored mapping relationship and adjustment coefficient between the consumption of electrophoretic paint and the power consumption. The paint consumption mapping unit is connected to the power calculation unit. The paint consumption mapping unit is configured to calculate the first actual consumption of the pigment and the second actual consumption of the emulsion based on the cumulative power consumption value. Add a decision unit, and add a communication connection between the decision unit and the paint consumption mapping unit; The paint consumption mapping unit is responsible for converting abstract physical electricity into specific material consumption. Its core is the pre-stored mapping relationship between electrophoretic paint consumption and electricity consumption, as well as the adjustment coefficient. In this embodiment, the mapping relationship is set as a linear relationship, that is, paint consumption M = k × Q, where Q is the cumulative electricity sent by the electricity calculation unit, and k is the adjustment coefficient obtained through a large number of process verifications. The physical basis of this relationship is Faraday's law of electrolysis. The quality of the electrophoretically deposited paint film is proportional to the amount of electricity passed through. The key point is that the system sets independent adjustment coefficients k1 and k2 for pigment paste and emulsion respectively. This is because pigment paste (mainly provides color and hiding power) and emulsion (mainly provides film-forming substances and properties) have inherent differences in deposition efficiency, solid content and consumption rate during the electrophoretic deposition process. The addition decision unit receives the first actual consumption (pigment paste) and the second actual consumption (emulsion) from the mapping unit. Its intelligence is reflected in the set addition threshold. This threshold introduces the concepts of "batch addition" and "economic batch." For example, the first addition threshold may be set to 200 kg, which means that an addition command is triggered only when the system calculates that the theoretical consumption of pigment paste has accumulated to 200 kg. This avoids the pumping execution unit from starting and stopping too frequently, thus extending the equipment life. Adding a larger and more stable amount each time helps maintain the relative stability of the total amount of electrophoresis tank solution and reduces frequent fluctuations in tank solution level and concentration caused by continuous micro-additions. It also facilitates matching with the material tank replacement cycle. The addition decision unit continuously monitors the actual consumption. Once the preset threshold is reached, it immediately generates an addition command containing the target addition amount (such as 200 kg pigment paste or 150 kg emulsion) and sends it to the pumping execution unit to start a complete addition cycle. The pumping execution unit is communicatively connected to the addition decision unit. The pumping execution unit includes a first paint adding pump for conveying pigment and a second paint adding pump for conveying emulsion. The weight metering unit is located on the output path of the first paint pump and the second paint pump. The weight metering unit is configured to measure the weight of the added pigment or emulsion in real time and generate a weight signal. The closed-loop control unit is communicatively connected to the weight metering unit and the pumping execution unit. The closed-loop control unit is configured to receive the weight signal and compare the weight signal with the preset target addition amount. When the weight signal indicates that the added weight has reached the target addition amount, it sends a stop command to the pumping execution unit. The pumping execution unit is responsible for translating decisions into actual actions. A pneumatic diaphragm pump is selected as the core pump body for the first paint adding pump (pigment paste) and the second paint adding pump (emulsion). The pneumatic diaphragm pump is chosen because: firstly, it is inherently safe and explosion-proof, making it very suitable for the environment of a painting workshop where flammable solvent vapors may exist; secondly, its simple structure, lack of mechanical seals, and low leakage risk, coupled with its ability to handle pigment pastes containing particulate matter and good wear resistance; and finally, by adjusting the inlet pressure and flow rate, the pump's outlet flow rate and head can be easily controlled. The pump's inlet and outlet are connected to the material tank and the electrophoresis tank's replenishment port via pipelines, and are equipped with pneumatic ball valves, which are uniformly controlled by a closed-loop control unit. The weighing unit is key to achieving accurate addition. A high-precision electronic scale is used as the weighing unit. This electronic scale is installed on the output path of the paint pump. The raw material barrels of pigment and emulsion are placed on an independent high-precision explosion-proof electronic scale. The accuracy of the electronic scale is usually ±0.1kg or even higher, and it has continuous analog (4-20mA) or digital communication output function. When the addition command is issued and the paint pump is started, the electronic scale begins to monitor the weight reduction value of the raw material barrel (or intermediate container) in real time and feeds back this weight signal to the closed-loop control unit at a high rate. The closed-loop control unit is internally set with a target addition amount (e.g., 200 kg). During pumping, the unit continuously receives weight signals and compares them with the target amount in real time. The control logic employs a "lead time" strategy: when the real-time weight change value approaches the target addition amount (e.g., reaching 195 kg), the control unit sends a deceleration or intermittent operation command to the pumping execution unit for fine-tuning. When the weight signal confirms that the added weight has accurately reached the target addition amount, the closed-loop control unit immediately sends a hard stop command to the pumping execution unit, cutting off the air supply and closing the relevant valves. This weight-based closed-loop feedback control fundamentally eliminates addition errors caused by factors such as pump efficiency fluctuations, pipeline pressure changes, and material viscosity differences, ensuring extremely high accuracy in the addition amount for each batch. The decision-making unit is configured with a first addition threshold corresponding to the first actual consumption and a second addition threshold corresponding to the second actual consumption. The decision-making unit is configured to generate a first addition instruction when the first actual consumption reaches the first addition threshold, and to generate a second addition instruction when the second actual consumption reaches the second addition threshold. The output of the decision-making unit is connected to a pipeline cleaning unit. The pipeline cleaning unit is configured to automatically execute the cleaning program after the pumping execution unit completes an addition operation and receives a stop command. The pipeline cleaning unit is an automated program triggered by the addition decision unit and executed by the closed-loop control unit. Its hardware foundation consists of a pre-installed cleaning fluid (usually deionized water) interface on the pump execution unit pipeline and a solenoid valve that controls the flow of the cleaning fluid. When an addition operation is completed, the closed-loop control unit issues a stop command, and the addition decision unit simultaneously sends a trigger signal to the pipeline cleaning unit. The cleaning program then starts: First, the system switches the relevant valves, switching the pump's suction end from the paint tank to the cleaning fluid tank; then, the paint pump is started briefly to draw in the cleaning fluid and pump it into the pipeline leading to the electrophoresis tank, rinsing the pump chamber and the inner wall of the pipeline for residual paint; finally, the waste liquid after rinsing is guided to a dedicated waste liquid collection tank instead of entering the electrophoresis tank to prevent dilution of the tank solution. This process is fully automated and requires no manual intervention, effectively preventing pigments or emulsions from solidifying and clumping inside the pipeline. The current acquisition unit reads current data by coupling with the communication interface of the production line's main control PLC. The pre-stored mapping relationship in the paint consumption mapping unit is a linear relationship, with paint consumption M=k×Q, where k is an adjustment coefficient and Q is the cumulative power consumption value. Both the first and second paint pumps are pneumatic diaphragm pumps. The output of the closed-loop control unit is connected to an alarm unit. The alarm unit is configured to trigger an audible and visual alarm when the weight signal fed back by the weight measuring unit does not reach the target amount within a preset time. The closed-loop control unit contains a time monitor. Upon receiving the addition command, this monitor starts timing. Under normal circumstances, the time from pump startup to the weight metering unit reporting that the target value has been reached should be within a reasonable timeframe (e.g., 3-5 minutes). The alarm unit has a preset time threshold (e.g., 10 minutes). If, due to reasons such as an empty raw material tank, pump failure, severe pipeline blockage, or weight metering unit malfunction, the weight signal fails to reach the target addition amount within the preset time, the closed-loop control unit will determine that the addition has exceeded the time limit and immediately send a command to the alarm unit. Once triggered, the alarm unit will activate a strong audible and visual alarm to alert on-site operators for timely intervention. Simultaneously, it will send a fault signal to the production line's main control system. If necessary, it can automatically pause the paint addition process or even automatically halt the electrophoresis production line to prevent batch product quality accidents caused by material shortages or imbalances, greatly improving the system's reliability and safety. The outputs of the power calculation unit, paint consumption mapping unit, and weight measurement unit are all communicatively connected to the data storage and display unit. The data storage and display unit is configured to record and display the cumulative power consumption, paint consumption, and paint addition data in real time. The data storage and display unit typically consists of an industrial touchscreen and a backend database. It establishes communication connections with the power calculation unit, paint consumption mapping unit, and weight measurement unit, collecting and classifying key data in real time. The power calculation unit provides a cumulative power curve marked with timestamps; the paint consumption mapping unit provides historical records of the theoretical consumption of pigments and emulsions; and the weight measurement unit provides detailed logs of the actual weight, time, and duration of each addition. The touchscreen main interface is designed as a dynamic flowchart, displaying real-time data such as current current, cumulative power consumption, theoretical consumption, and real-time weight of the raw material barrel. At the same time, it provides a historical data query interface, allowing operators to query statistical reports such as power consumption, unit consumption (such as the number of grams of paint consumed per ampere-hour), and addition frequency for any time period by time range (such as shift, day, month). It can also intuitively display the correlation between paint consumption and output (or power consumption) in the form of trend charts. By analyzing historical data, the coefficient k can be continuously corrected and adjusted to make the mapping relationship more accurate; accurate paint consumption data facilitates cost accounting and material inventory; when quality deviations occur, production data can be traced back to quickly locate whether it is related to the paint addition process, thus enabling rapid traceability and diagnosis of quality problems. The weight measuring unit is a high-precision electronic scale. This application ensures the synchronous addition of pigments and emulsions as needed through precise current tracking and closed-loop weight control, guaranteeing the stability of the bath composition from the source and significantly improving the consistency of coating quality. The batch addition strategy, combined with the automatic pipeline cleaning function, reduces the losses from frequent equipment start-ups and shutdowns, effectively prevents pipeline residues and bath fluctuations, improves system reliability, and reduces maintenance costs. The full-process data recording function provides accurate data support for production cost accounting and process optimization, and enables traceability of quality issues. This system comprehensively improves the level of refined and automated management of electrophoretic coating. The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An automatic paint application system for an electrophoretic coating line, characterized in that, include: A current acquisition unit is configured to acquire the current signal flowing through the electrophoresis workpiece in real time; A power calculation unit is communicatively connected to the current acquisition unit. The power calculation unit is configured to perform integral calculation on the current signal to obtain the cumulative power consumption value. The paint consumption mapping unit has a pre-stored mapping relationship and adjustment coefficient between the consumption of electrophoretic paint and the power consumption. The paint consumption mapping unit is communicatively connected to the power calculation unit. The paint consumption mapping unit is configured to calculate the first actual consumption of the pigment and the second actual consumption of the emulsion based on the cumulative power consumption value. A decision-making unit is added, which is communicatively connected to the paint consumption mapping unit. A pumping execution unit, which is communicatively connected to the adding decision unit, includes a first paint adding pump for conveying pigment and a second paint adding pump for conveying emulsion; A weight measuring unit is provided on the output path of the first paint pump and the second paint pump. The weight measuring unit is configured to measure the weight of the added pigment or emulsion in real time and generate a weight signal. A closed-loop control unit is communicatively connected to the weight metering unit and the pumping execution unit. The closed-loop control unit is configured to receive a weight signal and compare the weight signal with a preset target addition amount. When the weight signal indicates that the added weight has reached the target addition amount, a stop command is issued to the pumping execution unit.

2. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The addition decision unit is configured with a first addition threshold corresponding to the first actual consumption and a second addition threshold corresponding to the second actual consumption. The addition decision unit is configured to generate a first addition instruction when the first actual consumption reaches the first addition threshold, and to generate a second addition instruction when the second actual consumption reaches the second addition threshold.

3. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The output of the addition decision unit is communicatively connected to the pipeline cleaning unit, which is configured to automatically execute the cleaning program after the pumping execution unit completes an addition operation and receives a stop command.

4. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The current acquisition unit reads current data by coupling with the communication interface of the production line's main control PLC.

5. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The pre-stored mapping relationship in the paint consumption mapping unit is a linear relationship, where the paint consumption M = k × Q, and k is an adjustment coefficient, and Q is the cumulative power consumption value.

6. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, Both the first paint pump and the second paint pump are pneumatic diaphragm pumps.

7. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The output of the closed-loop control unit is communicatively connected to an alarm unit, which is configured to trigger an audible and visual alarm when the weight signal fed back by the weight measuring unit does not reach the target addition amount within a preset time.

8. The automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The outputs of the power calculation unit, paint consumption mapping unit, and weight measurement unit are all communicatively connected to a data storage and display unit. The data storage and display unit is configured to record and display the cumulative power consumption, paint consumption, and paint addition data in real time.

9. An automatic paint application system for an electrophoretic coating line according to claim 1, characterized in that, The weight measuring unit is a high-precision electronic scale.

Images