An automated intermittent spray control method and system for barrel paint spraying

Abstract

This invention discloses an automated intermittent spraying control method and system for roller painting. The method includes: calling preset process parameters; preheating and positioning the spray gun; executing an intermittent spraying cycle; periodically opening and closing the paint supply valve according to T1 / T2 timing parameters, and synchronously controlling the roller speed to be disturbed or reversed during each closed T2 pause period to forcibly disperse the workpiece and prevent adhesion; finally, curing and unloading. The system includes a parameter storage unit, a main control module, and execution modules such as multi-axis linkage and anti-adhesion drive coordinated by it. This invention solves the problem of workpiece adhesion through the timing coordination of "intermittent spraying" and "mechanical dispersion during pauses," and achieves standardized spraying quality and full automation of the operation by combining programmed calling of process parameters and high-precision linkage control.

Description

Technical Field

[0001] This invention belongs to the field of spraying control technology, and more specifically, relates to an automated intermittent spraying control method and system for roller spraying. Background Technology

[0002] Roller spray painting machines are widely used for batch coating of small workpieces. In existing roller spraying processes, continuous spraying is typically employed. However, continuous spraying can easily lead to excessively thick paint films on the workpiece surface. During roller tumbling, uncured workpieces are prone to sticking together, severely impacting coating yield and surface quality. Furthermore, existing equipment's spraying parameters (such as spray gun position, roller speed, and baking temperature) are mostly manually adjusted based on experience during line changes, lacking a standardized process program storage and recall mechanism. This results in significant quality variations between product batches and low line changeover efficiency. Existing control systems also cannot achieve high-precision linkage between spray gun posture, roller forward / reverse rotation, and spray start / stop actions, failing to meet the demands of high-quality spraying. Therefore, there is an urgent need for a control method and system that can programmatically recall process parameters and precisely control the intermittent spraying sequence to prevent workpiece sticking. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide an automated intermittent spraying control method and system for roller painting, which solves the problems of paint film adhesion and poor spraying uniformity by introducing parameterized calls and intermittent spraying timing control.

[0004] To achieve the above objectives, the first technical solution adopted by the present invention is: an automated intermittent spraying control method for roller painting, comprising the following steps:

[0005] S1. Parameter call: The main control module reads the preset process parameters, which include at least: roller speed and intermittent spraying sequence parameters, which include single spraying duration T1 and single pause duration T2.

[0006] S2. Intermittent spraying execution: The main control module controls the main drive motor to drive the inner cylinder to rotate at the speed of the roller; and controls the paint supply mechanism to operate according to the intermittent spraying timing parameters, performing a cyclical alternation operation of "start spraying T1 time - stop T2 time";

[0007] S3. Anti-adhesion control: During the cyclical alternation operation of step S2, the main control module controls the main drive motor to perform at least one speed disturbance or reverse action on the inner cylinder during the pause T2 time when the paint supply mechanism is closed each time.

[0008] Furthermore, the process parameters also include baking temperature; before step S2, a preheating step is also included: the main control module starts the hot air box to preheat to the baking temperature and runs stably for a preset time.

[0009] Furthermore, the process parameters also include the multi-dimensional pose coordinates of the spray gun; before step S2, there is also a posture positioning step: the main control module drives the multi-axis linkage actuator to adjust the spray gun to the target working posture according to the multi-dimensional pose coordinates of the spray gun.

[0010] Furthermore, it also includes curing and unloading steps: after the spraying cycle is completed, the main control module controls the tilting drive mechanism to tilt the oven to a set angle for unloading.

[0011] Furthermore, in step S3, the speed disturbance or reversal action specifically involves: during the pause T2 time, controlling the main drive motor to drive the inner cylinder to decelerate from the current speed to zero and then accelerate in the opposite direction to a set reversal speed, and then decelerating to zero and accelerating in the forward direction to restore the drum speed.

[0012] Furthermore, in step S2, while the paint supply mechanism is turned on, the main control module simultaneously starts the negative pressure exhaust device for the corresponding spraying area; after the spraying cycle is completed and a preset delay cleaning time has elapsed, the negative pressure exhaust device is turned off.

[0013] Furthermore, it also includes an automatic gun washing step: when the program sends a gun washing command, the main control module drives the linear motion module to automatically move the spray gun to the cleaning station on the left, and controls the paint supply valve to close and the gun washing liquid valve to open, and draws the gun washing liquid to rinse the spray gun.

[0014] To achieve the above objectives, the second technical solution adopted by the present invention is: an automated intermittent spraying control system applying the above control method, comprising:

[0015] The parameter storage unit is used to store multiple sets of process parameter combinations corresponding to different workpiece types;

[0016] The main control module is communicatively connected to the parameter storage unit and is used to read and parse the combination of process parameters and generate control commands based on the parsing results.

[0017] The timing control module, which is built into or connected to the main control module, is used to generate periodic on / off signals to control the paint supply solenoid valve based on the parsed intermittent spraying timing parameters.

[0018] The multi-axis linkage execution module includes a linear movement module controlled by the main control module, a first drive component, and a second drive component, used to drive the spray gun to move to the spatial pose determined by the multi-dimensional pose coordinates of the spray gun;

[0019] The anti-sticking drive module includes a main drive motor and a drive controller electrically connected thereto, which is controlled by the main control module and is used to perform a speed disturbance or reversal action on the roller during the period when the paint supply solenoid valve is disconnected.

[0020] Furthermore, it also includes a negative pressure linkage module, which includes a negative pressure exhaust device and a corresponding control circuit. The main control module is configured to send a linkage signal to the negative pressure linkage module to simultaneously start the negative pressure exhaust device when the paint supply solenoid valve is opened, and to close it after a delay after the spraying cycle is completed.

[0021] Furthermore, it also includes an automatic gun washing module, which includes a cleaning station on the left, a gun washing fluid pipeline, and a gun washing valve group controlled by the main control module; the main control module is configured to control the spray gun to move to the cleaning station, automatically close the paint supply valve and open the gun washing fluid valve for rinsing when it receives a gun washing command.

[0022] Furthermore, the parameter storage unit is an EEPROM chip, a Flash memory, or a solid-state drive.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention creatively proposes and implements a composite control method of "intermittent spraying + mechanical dispersing during pauses". By alternating between T1 spraying and T2 pauses, the paint film has time to buffer and level; and by using the pauses to disturb or reverse the rotation speed of the roller, the adhesion between workpieces is completely broken, solving the fatal flaw of "sticking" that is very easy to occur in batch roller spraying, and greatly improving the yield of finished products.

[0025] 2. This invention achieves the digitalization of process formulations. Through the parameter storage unit, the rotation speed, temperature, spray gun posture, and intermittent timing can be retrieved with a single click for workpieces of different shapes and materials, eliminating errors from manual adjustments and resulting in a high degree of standardization of spraying quality.

[0026] 3. The control method of the present invention links the negative pressure environmental protection device with the painting action at the bottom layer of the program, and precisely controls the start, stop and delay of the negative pressure, which not only ensures that the paint mist does not overflow, but also minimizes the overall energy consumption of the equipment.

[0027] 4. This invention innovatively integrates an automatic gun washing function. With a single button press, the spray gun is moved to the left-side cleaning station and the paint and cleaning fluid valves are automatically switched, achieving in-situ automatic rinsing without disassembly. This design not only eliminates the tedious and time-consuming process of manual disassembly and cleaning, but also fundamentally prevents damage to the spray gun from drops or impacts to the spray gun's firing pin caused by improper manual operation, providing excellent physical protection for the core coating components. Attached Figure Description

[0028] Figure 1 This is a flowchart of the automated intermittent spraying control method of the present invention.

[0029] Figure 2 This is a system block diagram of the automated intermittent spraying control system of the present invention. Detailed Implementation

[0030] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0031] Example 1: An automated intermittent spraying control method for roller painting, taking the batch painting of a certain type of small metal parts as an example, to explain in detail how the control method of the present invention is implemented.

[0032] like Figure 1 As shown, this method is executed through the hardware platform of a fully automatic roller spray painting machine. The operator only needs to select the corresponding workpiece formula number (such as "Formula 001") on the control panel, and the system will enter the automated control process. The steps are as follows:

[0033] Step S1, Process Parameter Retrieval: The main control module (using a PLC controller) reads the process parameter combination corresponding to "Recipe 001" from the parameter storage unit. This process parameter combination specifically includes:

[0034] Roller speed: 25 rpm; Baking temperature: 80℃; Spray gun multi-dimensional pose coordinates: X-axis (horizontal displacement) 150 mm, elevation angle (controlled by the first drive component) 30 degrees, yaw angle (controlled by the second drive component) 15 degrees; Intermittent spraying sequence parameters: single spraying time T1 = 3 seconds, single pause time T2 = 5 seconds, total number of cycles N = 20 times.

[0035] Step S2, Preheating and Initialization: The main control module starts the main drive motor via the frequency converter, causing the inner drum to rotate smoothly at 25 rpm. Simultaneously, it sends a command to the heater in the hot air box to initiate the preheating program, with a target temperature of 80℃. The system monitors the temperature sensor feedback in real time until the temperature reaches and stabilizes within the range of 80±2℃.

[0036] Step S3, Multi-axis Attitude Positioning: After preheating, the main control module sends control signals to each actuator based on the spray gun's position coordinates (150mm, 30°, 15°). Specifically, it sends pulse signals to the linear motion module (using a ball screw slide driven by a servo motor), causing it to move the spray gun base to 150mm on the X-axis; simultaneously, it drives the first drive component (such as a stepper motor) and the second drive component (such as a stepper motor) to precisely adjust the spatial attitude of the spray gun head to an elevation angle of 30 degrees and a yaw angle of 15 degrees. This process can be completed within seconds, ensuring that the spray gun is in the optimal spraying position and angle for this type of workpiece.

[0037] Step S4, Intermittent Spraying Execution: After the spray gun is in place, the timing control module built into the main control module (implemented based on a PLC timer function block) starts working. It first outputs a high-level signal to open the solenoid valve in the paint supply line, simultaneously activating the atomizing device to begin spraying paint onto the workpiece tumbling inside the roller. This moment marks the start of the spraying cycle. This open state lasts for T1 = 3 seconds. After 3 seconds, the timing control module outputs a low-level signal, closing the solenoid valve, stopping the spraying, and entering a pause period T2 = 5 seconds. This "3-second on - 5-second off" cycle repeats automatically. Crucially, at the instant the solenoid valve is opened (spraying begins), the main control module simultaneously sends a start signal to the control circuit of the negative pressure exhaust device, causing the negative pressure hood located behind the spraying station to immediately activate and promptly capture any overflowing paint mist.

[0038] Step S5, Anti-adhesion Control: This step is closely linked to the intermittent pause in Step S4. During the 3-second spraying period when the solenoid valve is open, the main control module controls the frequency converter to keep the main drive motor rotating at a uniform speed of 25 rpm, ensuring that the workpiece is evenly coated with paint. During the 5-second stop-spray period when the solenoid valve is closed, the main control module immediately triggers the preset "disturbance logic," controlling the main drive motor to execute the following sequence of actions via the frequency converter: decelerating from 25 rpm to 0 rpm in the first second; then, in the next 3 seconds, the drive motor accelerates in the reverse direction to 15 rpm and maintains a uniform reverse speed; finally, in the 5th second, decelerating from 15 rpm in reverse direction to 0 rpm and accelerating in the forward direction, returning to 25 rpm in forward rotation at the end of the T2 period. This forced "deceleration-reverse-recovery" action during the stop-spray period causes the workpiece in the roller to undergo violent relative movement, collision, and reorganization while it is losing its new paint coverage and the paint film is still in the leveling stage, thereby physically destroying any potential adhesion points.

[0039] Step S6, Curing and Automatic Unloading: After the sequential control module completes the 20th cycle, the main control module permanently closes the paint supply solenoid valve, ending the spraying stage. At this time, the main control module does not immediately shut off the negative pressure exhaust device, but instead starts a delay timer (e.g., 10 seconds) to allow the exhaust device to continue running, thus removing residual paint mist from the pipes and chamber, achieving environmentally friendly cleaning. Subsequently, the system enters the pure baking and curing stage, with the hot air box continuing to bake the workpiece at 80°C. After the curing process is completed, the main control module sends a command to the tilting drive mechanism (e.g., an electric push rod) to drive the entire oven to tilt forward to a preset angle (e.g., 45 degrees). The workpiece automatically slides into the receiving frame under gravity, completing fully automatic unloading.

[0040] This includes an automatic gun cleaning step: when the program sends a gun cleaning command, the main control module drives the linear motion module to automatically move the spray gun to the cleaning station on the left, and controls the paint supply valve to close and the cleaning fluid valve to open, drawing up the cleaning fluid to rinse the spray gun.

[0041] Example 2: An automated intermittent spraying control system

[0042] like Figure 2 As shown, this embodiment provides a hardware system for implementing the above method. This system is integrated into a fully automatic roller spray painting machine and mainly includes:

[0043] Parameter storage unit: It is an EEPROM chip, Flash memory or solid-state drive, which internally stores process parameter formulas for more than ten types of workpieces such as "small metal parts", "plastic parts" and "irregularly shaped parts".

[0044] Main control module: Responsible for all logical operations and instruction distribution. Internally, it uses ladder diagram programming to implement the functions of the timing control module, and can generate precise T1 / T2 periodic signals.

[0045] The multi-axis linkage execution module includes a linear slide module (responsible for X-axis movement), a first drive component (responsible for elevation angle adjustment), and a second drive component (responsible for yaw angle adjustment). All three components are connected to the PLC's pulse output port through corresponding drivers.

[0046] Anti-adhesion drive module: includes the main drive motor and a matching frequency converter. The control terminals of the frequency converter are connected to the digital output points of the PLC to receive forward rotation, reverse rotation, speed command, and disturbance trigger commands.

[0047] Negative pressure linkage module: includes a centrifugal fan, air collection duct, and control relay. The relay coil is controlled by an output point of the PLC to achieve synchronous start / stop and delayed shutdown with the solenoid valve signal.

[0048] Temperature control and tilting module: The temperature control part uses the analog output module of the PLC to control the solid-state relay, thereby adjusting the power of the heating tube of the hot air box; the tilting part uses the PLC to control an intermediate relay to drive the contactor of the electric push rod.

[0049] Automatic gun washing module: The automatic gun washing module includes a cleaning station on the left, a gun washing fluid pipeline, and a gun washing valve group controlled by the main control module; the main control module is configured to control the spray gun to move to the cleaning station, automatically close the paint supply valve and open the gun washing fluid valve for rinsing when it receives a gun washing command.

[0050] The system's workflow is as follows: After the operator selects a formula via a touchscreen (human-machine interface), the touchscreen sends instructions to the PLC. The PLC reads parameters from the EEPROM and then controls each module to work together in sequence, ultimately completing the entire automated operation from preheating, positioning, intermittent spraying (including anti-adhesion disturbance), negative pressure linkage, curing to automatic unloading.

[0051] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. An automated intermittent spray control method for drum painting, characterized by, Includes the following steps: S1. Parameter call: The main control module reads the preset process parameters, which include at least: roller speed and intermittent spraying sequence parameters, which include single spraying duration T1 and single pause duration T2. S2. Intermittent spraying execution: The main control module controls the main drive motor to drive the inner cylinder to rotate at the speed of the roller; and controls the paint supply mechanism to operate according to the intermittent spraying timing parameters, performing a cyclical alternation operation of "start spraying T1 time - stop T2 time"; S3. Anti-adhesion control: During the cyclical alternation operation of step S2, the main control module controls the main drive motor to perform at least one speed disturbance or reverse action on the inner cylinder during the pause T2 time when the paint supply mechanism is closed each time.

2. The control method according to claim 1, characterized by, The process parameters also include baking temperature; before step S2, a preheating step is also included: the main control module starts the hot air box to preheat to the baking temperature and runs stably for a preset time.

3. The control method according to claim 1, characterized by, The process parameters also include the multi-dimensional pose coordinates of the spray gun; before step S2, there is also a posture positioning step: the main control module drives the multi-axis linkage actuator to adjust the spray gun to the target working posture according to the multi-dimensional pose coordinates of the spray gun.

4. The control method according to claim 1, characterized by, It also includes curing and unloading steps: after the spraying cycle is completed, the main control module controls the tilting drive mechanism to tilt the oven to a set angle for unloading.

5. The control method according to claim 1, characterized in that, In step S3, the speed disturbance or reversal action specifically involves: during the pause T2 time, controlling the main drive motor to drive the inner cylinder to decelerate from the current speed to zero and then accelerate in the opposite direction to a set reversal speed, and then decelerating to zero and accelerating in the forward direction to restore the drum speed.

6. The control method according to claim 1, characterized in that, In step S2, while the paint supply mechanism is turned on, the main control module simultaneously starts the negative pressure exhaust device for the corresponding spraying area; after the spraying cycle is completed and a preset delay cleaning time has elapsed, the negative pressure exhaust device is turned off.

7. The control method according to claim 1, characterized in that, It also includes an automatic gun cleaning step: when the program sends a gun cleaning command, the main control module drives the linear motion module to automatically move the spray gun to the cleaning station on the left, and controls the paint supply valve to close and the cleaning fluid valve to open, and draws the cleaning fluid to rinse the spray gun.

8. An automated intermittent spraying control system applying the control method as described in any one of claims 1-7, characterized in that, include: The parameter storage unit is used to store multiple sets of process parameters corresponding to different workpiece types; The main control module is communicatively connected to the parameter storage unit and is used to read and parse the process parameters and generate control commands. The timing control module, which is built into or connected to the main control module, is used to generate periodic on / off signals to control the paint supply mechanism based on the parsed intermittent spraying timing parameters. The anti-sticking drive module includes a main drive motor and a drive controller electrically connected thereto, which is controlled by the main control module and is used to perform a speed disturbance or reversal action on the inner cylinder during the disconnection of the paint supply mechanism.

9. The control system according to claim 8, characterized in that, It also includes a multi-axis linkage execution module, including a linear movement module controlled by the main control module, a first drive component and a second drive component, for driving the spray gun to move to the target spatial pose; It also includes a negative pressure linkage module, wherein the main control module is configured to send a linkage signal to the negative pressure linkage module to simultaneously start the exhaust device when the paint supply mechanism is turned on, and to turn it off after a delay after the spraying cycle is completed.

10. The control system according to claim 8, characterized in that: It also includes an automatic gun washing module, which includes a cleaning station on the left, a gun washing fluid pipeline, and a gun washing valve group controlled by the main control module. The main control module is configured to control the spray gun to move to the cleaning station, automatically close the paint supply valve, and open the gun washing fluid valve for rinsing when it receives a gun washing command.

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