Intelligent temperature control repair soldering method, device, equipment and storage medium

Abstract

This application relates to the field of intelligent temperature control technology, and discloses an intelligent temperature-controlled rework soldering method, apparatus, equipment, and storage medium. The method includes: collecting the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate; calculating the first thermal conductivity coefficient between the workbench and the soldering iron tip and the second thermal conductivity coefficient between the soldering iron tip and the solder joint; adjusting the target temperature of the workbench; a first PID controller outputs a first PID output signal to drive the workbench to heat up according to the target temperature of the workbench; a second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal to obtain a third PID output signal; determining the start of solder melting; freezing the first PID output signal and the third PID output signal to maintain a preset soldering time; and performing current limiting or heating shutdown. This solves the problem of uneven heating of the solder joint caused by independent temperature control of the soldering iron tip and the workbench in the prior art, and achieves precise and controllable heating power.

Description

Technical Field

[0001] This application relates to the field of intelligent temperature control technology, and in particular to an intelligent temperature control method, apparatus, equipment and storage medium for rework soldering. Background Technology

[0002] In the rework soldering process of electronic products, components on the PCB substrate need to be disassembled and re-soldered, which requires extremely high temperature control precision. In traditional rework processes, the temperature control of the soldering iron tip and the preheating temperature control of the worktable are independent of each other, and each uses an independent temperature feedback loop for adjustment, resulting in a lack of coordination between the heat sources in the solder joint area.

[0003] This independent control mode has the following technical problems: First, the preheating temperature of the soldering iron tip and the work surface cannot be dynamically adjusted according to the actual heat flow distribution, which can easily lead to overheating of the work surface causing heat backflow or insufficient work surface temperature requiring excessive compensation from the soldering iron tip, resulting in uneven heating of the solder joints; Second, the heating current lacks an effective modulation mechanism, and instantaneous current surges may cause thermal damage to sensitive components; Third, the soldering process relies on the operator's experience and judgment, making it impossible to accurately identify the solder melting time and control the cooling rate. Summary of the Invention

[0004] This application provides an intelligent temperature-controlled rework soldering method, apparatus, equipment, and storage medium, thereby solving the problem of uneven heating of solder joints caused by independent temperature control of the soldering iron tip and the worktable in the prior art, and realizing precise and controllable heating power.

[0005] The first aspect of this application provides a smart temperature-controlled rework soldering method, the smart temperature-controlled rework soldering method comprising: Collect the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate, and calculate the first thermal conductivity coefficient between the workbench and the soldering iron tip and the second thermal conductivity coefficient between the soldering iron tip and the solder joint. Adjust the target temperature of the platform based on the first thermal conductivity coefficient and the second thermal conductivity coefficient; The first PID controller outputs a first PID output signal to drive the workbench to heat up according to the target temperature of the workbench. The second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal to obtain a third PID output signal. The second thermal conductivity coefficient is monitored to determine the start of solder melting, and the first PID output signal and the third PID output signal are frozen to maintain a preset welding time. The cooling process is controlled by adjusting the cooling rate of the PCB substrate to regulate the target temperature of the platform, and by performing current limiting or shutting off heating.

[0006] In conjunction with the first aspect, in a first implementation of the first aspect of the present invention, the step of collecting the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate, and calculating the first thermal conductivity coefficient between the workbench and the soldering iron tip and the second thermal conductivity coefficient between the soldering iron tip and the solder joint, includes: Collect the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate; The first thermal conductivity coefficient is calculated based on the first temperature difference between the real-time temperature of the soldering tip and the preheating temperature of the workbench, the first contact thermal resistance between the workbench and the soldering tip, and the sampling time interval. The second thermal conductivity coefficient is calculated based on the second temperature difference between the real-time temperature of the soldering iron tip and the temperature of the PCB substrate, the second contact thermal resistance of the solder layer, and the sampling time interval.

[0007] In conjunction with the first aspect, in a second implementation of the first aspect of the present invention, adjusting the target temperature of the platform based on the first thermal conductivity coefficient and the second thermal conductivity coefficient includes: The thermal conductivity fusion coefficient is calculated based on the ratio of the first thermal conductivity coefficient to the sum of the first thermal conductivity coefficient and the second thermal conductivity coefficient. When the thermal conductivity fusion coefficient is greater than the first threshold, the preheating temperature of the countertop is determined to be too high; when the thermal conductivity fusion coefficient is less than the second threshold, the preheating temperature of the countertop is determined to be insufficient. The tabletop temperature adjustment amount is calculated based on the deviation between the heat conduction fusion coefficient and the preset ideal value and the preset adjustment coefficient. The target tabletop temperature is then adjusted according to the reference tabletop temperature and the tabletop temperature adjustment amount.

[0008] In conjunction with the first aspect, in a third implementation of the first aspect of the present invention, the first PID controller outputs a first PID output signal to drive the workbench to heat up according to the target temperature of the workbench, and the second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal to obtain a third PID output signal, including: The first PID controller calculates the first control error between the target temperature of the work surface and the preheating temperature of the work surface, and outputs a first PID output signal based on the first control error to drive the work surface to heat up to the preheating temperature and stabilize it. The target temperature of the soldering iron tip is determined by looking up a table based on the type of component to be repaired. The second PID controller calculates the second control error between the target temperature of the soldering iron tip and the real-time temperature of the soldering iron tip. Based on the second control error, a second PID output signal is output to drive the soldering iron tip to heat up, and the heating rate of the soldering iron tip is monitored and controlled within the preset heating rate range. The first PID output signal and the second PID output signal are allocated according to the heat conduction fusion coefficient. The current margin is calculated based on the real-time heating current to obtain the current limiting coefficient, which is then used to modulate the second PID output signal to obtain the third PID output signal.

[0009] In conjunction with the first aspect, in a fourth implementation of the first aspect of the present invention, the step of allocating the first PID output signal and the second PID output signal according to the thermal conductivity fusion coefficient, and modulating the second PID output signal with a current limiting coefficient based on the current margin calculated from the real-time heating current to obtain the third PID output signal includes: When the thermal conduction fusion coefficient is greater than the first threshold, the first PID output signal is adjusted according to the first proportional coefficient; when the thermal conduction fusion coefficient is less than the second threshold, the second PID output signal is adjusted according to the second proportional coefficient. The real-time heating current of the soldering iron tip heating circuit is collected, and the current margin is calculated based on the real-time heating current and the peak current threshold determined according to the power of the soldering iron tip. The current limiting coefficient is determined based on the current margin, and the second PID output signal is modulated based on the current limiting coefficient to obtain the third PID output signal.

[0010] In conjunction with the first aspect, in a fifth implementation of the first aspect of the present invention, the step of monitoring the second thermal conductivity coefficient to determine the start of solder melting and freezing the first PID output signal and the third PID output signal to maintain a preset welding time includes: Calculate the difference between the second thermal conductivity coefficient of the current cycle and the second thermal conductivity coefficient of the previous cycle, and calculate the ratio of the difference to the second thermal conductivity coefficient of the previous cycle to obtain the rate of change of thermal conductivity coefficient; When the rate of change of the thermal conductivity coefficient is greater than a preset rate of change threshold, it is determined that the solder melting has started and a control signal freeze command is triggered. Based on the control signal freeze command, the first PID output signal and the third PID output signal are locked to their current values ​​and maintained for the preset welding time.

[0011] In conjunction with the first aspect, in a sixth implementation of the first aspect of the present invention, the step of controlling the cooling process by regulating the target temperature of the platform based on the cooling rate of the PCB substrate temperature, and performing current limiting or heating shutdown, includes: Calculate the cooling rate of the PCB substrate temperature, determine whether the cooling rate is within the preset cooling rate range, and obtain the cooling rate deviation state; When the cooling rate deviation state is too fast, the first PID output signal is increased to raise the target temperature of the platform; when the cooling rate deviation state is too slow, the first PID output signal is decreased. The electrostatic voltage of the workbench surface is collected. When the electrostatic voltage of the workbench surface exceeds the preset electrostatic threshold, current limiting is applied to the third PID output signal. When the leakage current exceeds the preset leakage current threshold, the heating is turned off.

[0012] A second aspect of this application provides an intelligent temperature-controlled rework soldering device, the intelligent temperature-controlled rework soldering device comprising: The data acquisition module is used to collect the preheating temperature of the workbench, the real-time temperature of the soldering tip, and the temperature of the PCB substrate, and to calculate the first thermal conductivity coefficient between the workbench and the soldering tip and the second thermal conductivity coefficient between the soldering tip and the solder joint. The adjustment module is used to adjust the target temperature of the platform based on the first thermal conductivity coefficient and the second thermal conductivity coefficient; The drive module is used for the first PID controller to output a first PID output signal to drive the workbench to heat up according to the target temperature of the table surface, and the second PID controller to output a second PID output signal to drive the soldering iron tip to heat up and calculate the current margin to modulate the second PID output signal to obtain a third PID output signal. The maintenance module is used to monitor the second thermal conductivity coefficient to determine the start of solder melting, and freeze the first PID output signal and the third PID output signal to maintain a preset welding time. The execution module is used to control the cooling process by adjusting the target temperature of the platform based on the cooling rate of the PCB substrate temperature, and to perform current limiting or heating shutdown.

[0013] A third aspect of this application provides an electronic device, comprising: a memory and at least one processor, wherein the memory stores instructions; the at least one processor invokes the instructions in the memory to cause the electronic device to perform the above-described intelligent temperature-controlled rework soldering method.

[0014] A fourth aspect of this application provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the above-described intelligent temperature-controlled rework soldering method.

[0015] Compared with existing technologies, this application has the following advantages: By establishing a multi-point temperature acquisition system to obtain the preheating temperature of the workbench, the real-time temperature of the soldering tip, and the temperature of the PCB substrate, the first thermal conductivity coefficient between the workbench and the soldering tip and the second thermal conductivity coefficient between the soldering tip and the solder joint are calculated. This allows for the construction of a thermal conductivity fusion coefficient to quantify the contribution of workbench preheating to the solder joint temperature, achieving accurate characterization of the heat flow distribution from the dual heat sources. Based on the thermal conductivity fusion coefficient, the target temperature of the workbench is dynamically adjusted, and a cascaded PID control structure is used to drive the workbench heating and the soldering tip temperature rise separately. The power ratio of the two PID output signals is allocated in real time according to the thermal conductivity fusion coefficient, solving the problem of uneven solder joint heating caused by independent temperature control of the soldering tip and workbench in existing technologies. A peak current modulation mechanism is introduced, and the current limiting coefficient obtained by calculating the current margin is used to modulate the second PID output signal, effectively preventing thermal damage to sensitive components caused by instantaneous current surges. By monitoring the abrupt change characteristics of the second thermal conductivity coefficient, the moment when the solder melt begins is automatically determined and the control signal is frozen to maintain a stable soldering temperature. During the cooling stage, the target temperature of the table is controlled in a closed loop based on the cooling rate of the PCB substrate temperature to ensure that the cooling rate is within a reasonable range and to avoid solder joint cracks. At the same time, combined with the real-time monitoring of electrostatic voltage and leakage current, current limiting or heating is turned off, thus achieving precise and controllable heating power. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0018] Figure 1 This is a flowchart illustrating the intelligent temperature-controlled rework soldering method provided in an embodiment of the present invention; Figure 2 This is a schematic block diagram of the intelligent temperature-controlled rework soldering device provided in an embodiment of the present invention; Figure 3 This is a schematic block diagram of the structure of the electronic device provided in the embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should also be further understood that the term "and / or" as used in this application specification and the appended claims refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations. See also Figure 1 One embodiment of the intelligent temperature-controlled rework soldering method in this application includes: Step 100: Collect the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate; calculate the first thermal conductivity coefficient between the workbench and the soldering iron tip and the second thermal conductivity coefficient between the soldering iron tip and the solder joint. Specifically, a temperature monitoring network consisting of three types of sensors is established. The preheating temperature of the workbench is acquired in real time via a K-type thermocouple embedded 3mm deep within the workbench. A MAX6675 chip with a digital cold junction compensation circuit is used to achieve high-precision temperature signal conversion, with a temperature resolution of 0.25℃. The real-time temperature of the soldering tip is measured using a PT100 platinum resistance temperature sensor embedded 5mm from its tip. The sensor employs a four-wire connection to suppress lead resistance errors, and the signal is converted into a digital signal by a dedicated RTD conditioning chip, MAX31865, achieving a temperature resolution of 0.0℃. 3125℃; simultaneously, the PCB substrate temperature is collected by an MLX90614 infrared temperature measurement module located 150mm above the solder joint area. The field of view of the infrared temperature measurement module is set to 90 degrees and the focus is on the soldering area. Its output reflects the true surface temperature of the substrate after emissivity correction. The emissivity coefficient of the FR-4 PCB material is set to 0.90. The three sets of sensors sample synchronously at a frequency of 100Hz and the clock signal is provided by the timer TIM2 of the main control chip STM32F407. The temperature data is transmitted to the circular buffer in real time through DMA to ensure the continuity of data acquisition and low latency characteristics. After temperature sampling is completed, a first thermal conductivity coefficient is calculated based on the first temperature difference between the real-time temperature of the soldering tip and the preheated temperature of the workbench, and the first contact thermal resistance between the workbench and the soldering tip. The first contact thermal resistance is set to 0.15 K / W in the pre-calibration experiment, with a sampling interval of 10ms. A second thermal conductivity coefficient is calculated based on the second temperature difference between the real-time temperature of the soldering tip and the PCB substrate temperature, and the second contact thermal resistance of the solder layer. The second contact thermal resistance is determined by referring to a table based on the solder type: 0.08 K / W for lead-free solder SAC305 and 0.12 K / W for leaded solder SnPb63 / 37. The calculation results of the two thermal conductivity coefficients are written to the dual-port RAM in real time and continuously updated within each 10ms control cycle.

[0023] Step 200: Adjust the target temperature of the platform based on the first thermal conductivity coefficient and the second thermal conductivity coefficient; Specifically, a real-time dynamically changing thermal conductivity fusion coefficient is constructed by using the ratio of the first thermal conductivity coefficient to the sum of the first and second thermal conductivity coefficients as the calculation basis. This fusion coefficient serves as the core criterion for temperature control logic. When the thermal conductivity fusion coefficient is greater than the first threshold, for example, exceeding 0.6, it is determined that the current table preheating temperature is too high, indicating that too much heat is being conducted from the table to the soldering iron tip, which can lead to heat backflow. This can cause the soldering iron tip to experience temperature overshoot even at low power. In this case, the heating power of the worktable is reduced to avoid waste and localized overheating. When the fusion coefficient is less than the second threshold, for example, below 0.3, it is determined that the table preheating is insufficient, and the table's support for the solder joint temperature is weak. The target temperature of the worktable is appropriately increased, or the heating power of the soldering iron tip is increased in conjunction with this to maintain the thermal balance of the soldering temperature zone. The deviation between the current heat conduction fusion coefficient and the ideal value is used as the adjustment benchmark. Combined with the preset adjustment coefficient, the dynamic adjustment amount of the table surface temperature is calculated. The dynamic adjustment amount is then added to or subtracted from the preset benchmark table surface temperature to form the updated target table surface temperature value. The preset benchmark temperature is set to 180℃ as the initial reference value for preheating control. The adjustment coefficient is selected as an empirical parameter based on the thermal response characteristics. For example, each 0.01 deviation corresponds to a 1℃ correction range.

[0024] Step 300: The first PID controller outputs a first PID output signal to drive the workbench to heat up according to the target temperature of the table. The second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal to obtain the third PID output signal. Specifically, the first PID controller acquires the updated target temperature of the workbench and calculates the first control error based on the real-time collected preheating temperature of the workbench. The first control error reflects the deviation between the current actual temperature of the workbench and the preset temperature. The first PID controller uses this as input to perform proportional, integral, and derivative calculations, and outputs a first PID signal to drive the nichrome alloy heating wire to heat to the target temperature. Through closed-loop control, the workbench temperature is maintained within ±2℃ of the target value to form a continuous and uniform preheating environment. The corresponding soldering tip target temperature is retrieved from the preset temperature database according to the package type of the electronic component to be repaired. For example, 330℃ is set for 0402 / 0603 package resistors, 310℃ for QFP / BGA packaged integrated circuits, and 350℃ for connector assemblies. The second PID controller then compares the target temperature with the currently collected real-time temperature of the soldering tip, calculates the second control error, and outputs a second PID signal based on the second control error to drive the IGBT power device to control the heating power of the soldering tip. During the heating process, the heating rate of the soldering iron tip is calculated and limited in real time. When the heating rate exceeds 18℃ / s, the PID output is limited to 85% of the current value; when it is below 12℃ / s, the output is increased to 120% of the original value to prevent temperature shock from damaging the solder joints. To achieve coordinated control between heat sources, the heat energy distribution ratio is adjusted according to the real-time change trend of the thermal conductivity fusion coefficient. When the thermal conductivity fusion coefficient is higher than 0.6, the first PID output is reduced to decrease the table power, while the second PID output remains unchanged. When the thermal conductivity fusion coefficient is lower than 0.3, the table heating level is maintained and the second PID output is enhanced to ensure that the soldering iron tip receives sufficient compensating heat. Based on the above soldering iron tip heating control, a current protection mechanism is integrated. The heating circuit current is collected in real time and compared with a preset peak current threshold to calculate the current margin. The current margin is used to assess the distance between the current level and the safety critical point. The current limiting coefficient is divided according to the margin range. For example, when the margin is between 0.05 and 0.10, the current limiting coefficient is set to 0.70. This coefficient is used to modulate the second PID output signal to obtain the third PID signal.

[0025] Step 400: Monitor the second thermal conductivity coefficient to determine the start of solder melting, and freeze the first PID output signal and the third PID output signal to maintain the preset welding time; Specifically, during the soldering stage, a high-frequency sampling mechanism continuously calculates the second thermal conductivity coefficient every 10 milliseconds. This second thermal conductivity coefficient is determined by the temperature difference between the soldering iron tip and the PCB substrate, the contact thermal resistance of the solder layer, and the sampling interval, effectively reflecting the changing state of the thermal conductivity at the solder joint interface. To identify the physical characteristics of the solder transitioning from a solid to a liquid state, the currently calculated second thermal conductivity coefficient is recorded in each control cycle and compared with the coefficient from the previous cycle. The difference is calculated and divided by the coefficient from the previous cycle to obtain the relative rate of change of the thermal conductivity coefficient. This reflects the abrupt change in contact thermal resistance and the rapid increase in heat flow caused by the filling of the air gap with liquid solder at the moment of solder melting. When the rate of change of the thermal conductivity coefficient exceeds a preset threshold, such as 30%, the system determines that the solder has reached its melting point and begun to melt, indicating that the soldering process has entered a critical stage. At this point, a control signal freeze command is triggered to stabilize the current heating state and prevent temperature field disturbances caused by control fluctuations from affecting the solder wetting effect and solder joint formation quality. In response to the freeze command, the table heating signal output by the first PID controller and the third PID signal after current limiting modulation, which is the control signal used to drive the soldering tip heating, are locked to the current output value at the trigger moment. They no longer respond to subsequent error updates or external disturbances and remain locked for a complete preset soldering time cycle. The cycle is set to 5 seconds or adjusted according to the type of solder and component type, so that the solder can fully melt, wet and complete the metal bonding process between the pad and the pin in the controlled thermal field.

[0026] Step 500: Based on the cooling rate of the PCB substrate temperature, control the cooling process by adjusting the target temperature of the cooling table and performing current limiting or heating shutdown.

[0027] Specifically, after entering the cooling stage, the surface temperature of the PCB substrate is continuously collected, and the temperature difference between two consecutive sampling time points is calculated at a rate of one second to determine the cooling rate. The cooling rate reflects the dynamic trend of heat loss from the substrate. The current cooling rate is compared with a preset cooling rate range, for example, an ideal range of 5°C to 8°C per second. Based on this, the deviation of the cooling rate is judged. If it is determined that the cooling is too fast, i.e., the temperature drop rate exceeds 8°C / s, the output signal of the first PID controller is actively increased to raise the target temperature of the worktable. This forms a thermal buffer through the heating of the worktable to slow down the temperature drop in the solder joint area, preventing solder joint cracks or uneven solder shrinkage leading to poor soldering due to excessive thermal stress. If it is determined that the cooling is too slow, i.e., the temperature drop rate is less than 5°C / s, the output signal of the first PID controller is reduced, which is equivalent to reducing the heating power of the worktable. This allows the soldering area to complete the heat dissipation process in a shorter time, improving rework efficiency and ensuring process cycle time. While performing cooling control, the electrostatic state of the workbench is monitored synchronously. The electrostatic voltage between the workbench and ground is collected. When the detected value exceeds the set electrostatic threshold, such as 200V, it is determined that there is a risk of excessive electrostatic accumulation. At this time, the heating is not directly shut off. Instead, current limiting processing is performed on the third PID output signal. For example, the original output signal is attenuated to 30% to reduce the power output. This maintains basic thermal control requirements while preventing electrostatic discharge from damaging sensitive components. The leakage current differential value in the circuit is detected in real time through the integrated power supply protection module. When the leakage current is detected to continuously exceed the set threshold, such as 30mA, and remain there for more than 50 milliseconds, emergency shutdown logic is executed. This includes pulling down the gate voltage of the IGBT power device to the cutoff state and disconnecting the solid-state relay, thereby interrupting the power supply path of the workbench heating and soldering tip.

[0028] In one specific embodiment, the process of performing step 100 may specifically include the following steps: Collect the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate; The first thermal conductivity coefficient is calculated based on the first temperature difference between the real-time temperature of the soldering tip and the preheating temperature of the workbench, the first contact thermal resistance between the workbench and the soldering tip, and the sampling time interval. The second thermal conductivity coefficient is calculated based on the second temperature difference between the real-time temperature of the soldering iron tip and the temperature of the PCB substrate, the second contact thermal resistance of the solder layer, and the sampling time interval.

[0029] Specifically, the preheating temperature of the workbench is acquired using a K-type thermocouple embedded 3 mm deep within the workbench structure. This K-type thermocouple is connected to the MAX6675 digital temperature acquisition chip, utilizing its integrated cold junction compensation and digital SPI communication capabilities to achieve high-precision, digital acquisition of the workbench temperature with a resolution of 0.25℃. The data is then transmitted to the DMA cache of the main control chip at a frequency of 100Hz. Simultaneously, the real-time temperature acquisition of the soldering tip uses a PT100 platinum resistance temperature sensor located 5 mm inside its heating tip, and a four-wire connection effectively eliminates the impact of transmission lead resistance on measurement accuracy. To mitigate interference, the output signal is converted from RTD to digital signal via the MAX31865 converter chip, achieving a resolution of 0.03125℃, and is sampled at the same frequency as the table surface temperature acquisition system. The third key temperature acquisition point is located 150 mm above the PCB substrate, utilizing an MLX90614 infrared non-contact temperature sensor with a field of view set to 90 degrees and the focus pointing towards the area to be soldered. The emissivity parameter is adjusted to adapt to different PCB materials; for common FR-4 board, the emissivity is set to 0.90. The temperature sensor also feeds back the infrared temperature measurement results to the main control system at a frequency of 100Hz. Based on the physical heat conduction process, the first thermal conductivity coefficient between the workbench and the soldering tip and the second thermal conductivity coefficient between the soldering tip and the solder joint are calculated. The first thermal conductivity coefficient describes the rate at which heat is transferred from the workbench to the soldering tip. Specifically, the magnitude of the first thermal conductivity coefficient is directly proportional to the difference between the real-time temperature of the soldering tip and the temperature of the workbench, and inversely proportional to the product of the preset first contact thermal resistance and the sampling time interval. The greater the temperature difference, the faster the heat transfer; conversely, the greater the contact thermal resistance or the shorter the heat transfer time, the lower the transfer efficiency. The first contact thermal resistance was fixed at 0.15 K / W through experimental calibration, with a sampling interval of 10 milliseconds. The second thermal conductivity coefficient measures the ability of heat to be transferred from the soldering iron tip to the solder joint. Its calculation logic is as follows: the greater the difference between the temperature of the soldering iron tip and the PCB surface temperature, the higher the heat absorption rate of the solder joint; the second thermal conductivity coefficient is obtained by dividing the temperature difference by the product of the solder layer contact thermal resistance and the time interval. Unlike the table surface, the contact thermal resistance is preset according to the solder type, with 0.08 K / W for SAC305 solder and 0.12 K / W for SnPb63 / 37 solder; the solder type is automatically identified and the corresponding resistance value is applied before soldering begins, and the heat transfer rate is calculated in conjunction with the 10-millisecond time interval and the real-time temperature difference.

[0030] In one specific embodiment, the process of performing step 200 may specifically include the following steps: The thermal conductivity fusion coefficient is calculated based on the ratio of the first thermal conductivity coefficient to the sum of the first and second thermal conductivity coefficients. When the thermal conductivity fusion coefficient is greater than the first threshold, the preheating temperature of the countertop is determined to be too high; when the thermal conductivity fusion coefficient is less than the second threshold, the preheating temperature of the countertop is determined to be insufficient. The tabletop temperature adjustment is calculated based on the deviation between the thermal conductivity fusion coefficient and the preset ideal value and the preset adjustment coefficient. The target tabletop temperature is then adjusted according to the reference tabletop temperature and the tabletop temperature adjustment.

[0031] Specifically, the thermal conductivity fusion coefficient is calculated by ratioing the first thermal conductivity coefficient to the sum of the first and second thermal conductivity coefficients. This ratio reflects the heat flow distribution trend under the current operating conditions and varies between 0 and 1. A value closer to 1 indicates a stronger dominance of the worktable over the overall heat flow. The thermal conductivity fusion coefficient is compared with two empirical thresholds. When the fusion coefficient is greater than the first threshold, for example, 0.6, it is determined that the current worktable is overheated, indicating that the heat released by the worktable has been excessively conducted upwards to the soldering tip, which can easily cause local temperature overshoot and instability in the soldering temperature zone. In this case, the target temperature of the worktable is actively reduced to weaken its heat source influence, thereby avoiding power redundancy and energy waste. When the fusion coefficient is less than the second threshold, for example, 0.3, it is determined that the current worktable preheating level is insufficient, indicating that the worktable's heat flow support capacity is weak, and the soldering tip needs to bear more heating load, thus affecting the temporal stability of the solder joint temperature. In this case, the worktable temperature is increased to achieve thermal field balance. To achieve continuous and responsive temperature adjustment, the deviation between the current fusion coefficient and the ideal target value is used as the basis for dynamic adjustment. This deviation is combined with a preset adjustment coefficient to calculate the tabletop temperature adjustment. Based on historical experiments, the preset adjustment coefficient is set so that every 0.01 deviation corresponds to a 1℃ temperature correction. For example, if the fusion coefficient deviates from the ideal value by more than ±0.1 (0.45), the target tabletop temperature will be increased or decreased by 5℃ to 10℃. The tabletop temperature adjustment is then superimposed on the reference tabletop temperature to form a new target tabletop temperature. The reference tabletop temperature is set to 180℃ and used as the setpoint for closed-loop control in the outer-loop PID controller.

[0032] In one specific embodiment, the process of performing step 300 may specifically include the following steps: The first PID controller calculates the first control error between the target temperature of the worktable and the preheating temperature of the worktable, and outputs the first PID output signal based on the first control error to drive the worktable to heat up to the preheating temperature and stabilize it. The target temperature of the soldering tip is determined by looking up a table based on the type of component to be repaired. The second PID controller calculates the second control error between the target temperature of the soldering tip and the real-time temperature of the soldering tip. Based on the second control error, the second PID output signal is output to drive the soldering iron tip to heat up, and the heating rate of the soldering iron tip is monitored and controlled within the preset heating rate range. The first PID output signal and the second PID output signal are allocated according to the thermal conductivity fusion coefficient. The current margin is calculated based on the real-time heating current to obtain the current limiting coefficient, which modulates the second PID output signal to obtain the third PID output signal.

[0033] Specifically, the first PID controller acquires the dynamically adjusted target temperature of the worktable and continuously collects the current preheating temperature of the worktable. The difference between the two is used to calculate the first control error. This first control error serves as the input variable for the outer-loop PID controller. After calculation using proportional, integral, and derivative algorithms, the first PID control signal is output. This signal drives the nickel-chromium alloy heating wires inside the worktable to perform constant-power heating, thereby exciting a solid-state relay at a fixed frequency to switch the power on and off. This gradually brings the worktable temperature closer to the target setpoint and maintains stability within ±2℃. Based on the package type or process requirements of the components to be soldered in the current rework task, the system retrieves the matching target temperature value for the soldering iron tip from a preset database. For example, 330℃ corresponds to a 0402 resistor, 310℃ to a BGA chip, and 350℃ to a high-power connector. This target temperature is input to the second PID controller, which compares it with the real-time collected soldering iron tip temperature to determine the second control error. Based on this error, a second PID control signal is calculated and output to adjust the on-time of the IGBT power switching device and the PWM duty cycle, controlling the dynamic change of the soldering iron tip heating power and achieving closed-loop control during the heating process. To prevent excessively rapid heating that could cause localized thermal shock or solder joint deformation, the system continuously monitors the soldering iron tip heating rate and calculates the temperature change rate in real time. When the heating rate exceeds 18℃ / s, the second PID output is automatically reduced to 85% of its current value; when the heating rate is below 12℃ / s, the output is increased to 120% of its original value, ensuring a stable temperature rise. The output signals of the first and second PID controllers are dynamically allocated based on a real-time updated heat conduction fusion coefficient. When the fusion coefficient is greater than 0.6, it indicates that the heat output from the work surface is too high, so the first PID signal is halved while the second PID output remains unchanged. When the fusion coefficient is less than 0.3, it indicates that the heat output from the work surface is insufficient, so the second PID signal output is increased to maintain constant heating of the work surface. A current protection mechanism is introduced while performing soldering tip temperature control. The actual current of the heating circuit is collected in real time and the current margin is calculated by comparing it with the rated peak current threshold of the equipment. When the margin is too small, a current limiting coefficient is assigned to modulate the output of the second PID controller. The current limiting coefficient is divided into levels such as 0.85, 0.70, or 0.50 according to the margin range. The second PID signal is multiplied by the current limiting coefficient to obtain the third PID output signal.

[0034] The process includes: driving the soldering tip to heat up based on the second PID output signal of the second control error; monitoring the heating rate of the soldering tip and controlling it within the preset heating rate range; further including: determining whether the real-time temperature of the soldering tip has reached a preset proportional threshold of the target temperature of the soldering tip; triggering a control mode switching signal when the preset proportional threshold is reached, switching from rapid heating mode to fine temperature control mode; adjusting the integral and derivative coefficients of the second PID controller based on the control mode switching signal, adjusting the integral coefficient from the first integral coefficient value to the second integral coefficient value to enhance steady-state accuracy, and adjusting the derivative coefficient from the first derivative coefficient value to the second derivative coefficient value to enhance anti-interference capability; calculating the deviation of the heat conduction fusion coefficient from the preset ideal value; when the deviation of the fusion coefficient exceeds the preset deviation threshold, compensating and adjusting the second integral coefficient value and the second derivative coefficient value according to the deviation of the fusion coefficient; recalculating the second PID output signal based on the compensated and adjusted integral and derivative coefficients, and establishing a temperature platform to provide a stable thermal environment for the soldering operation.

[0035] The process of monitoring and controlling the heating rate of the soldering iron tip within a preset heating rate range includes: performing time derivative calculations on the real-time temperature of the soldering iron tip to obtain the heating rate of the soldering iron tip for the current cycle; determining the deviation between the heating rate of the soldering iron tip and the preset target heating rate; determining that the heating rate is too fast when it exceeds the preset upper limit heating rate threshold, and too slow when it is less than the preset lower limit heating rate threshold; when the heating rate is too fast, calculating the overshoot between the heating rate of the soldering iron tip and the preset upper limit heating rate threshold, and reducing the output signal of the second PID controller based on the overshoot using a first power limiting proportional coefficient to prevent temperature surges; when the heating rate is too slow, calculating the undershoot between the heating rate of the soldering iron tip and the preset lower limit heating rate threshold, and enhancing the output signal of the second PID controller based on the undershoot using a second power enhancement proportional coefficient to accelerate the heating process.

[0036] In one specific embodiment, the process of allocating a first PID output signal and a second PID output signal according to the thermal conductivity fusion coefficient, calculating the current margin based on the real-time heating current to obtain a current limiting coefficient to modulate the second PID output signal, and obtaining the third PID output signal can specifically include the following steps: When the thermal conductivity fusion coefficient is greater than the first threshold, the first PID output signal is adjusted according to the first proportional coefficient; when the thermal conductivity fusion coefficient is less than the second threshold, the second PID output signal is adjusted according to the second proportional coefficient. Collect the real-time heating current of the soldering iron tip heating circuit, and calculate the current margin based on the real-time heating current and the peak current threshold determined according to the power of the soldering iron tip. The current limiting coefficient is determined based on the current margin, and the second PID output signal is modulated based on the current limiting coefficient to obtain the third PID output signal.

[0037] Specifically, the heat conduction fusion coefficient is calculated in real time to dynamically assess the proportion of heat flow in the heat conduction path of the soldering iron tip from the workbench surface. When the heat conduction fusion coefficient is greater than the first threshold, for example, exceeding 0.6, it indicates that the workbench surface contributes too much to the overall soldering heat field. In this case, a downsampling operation is performed, attenuating the output signal of the first PID controller according to a set first proportional coefficient, for example, multiplying it by 0.5, so that the heat output power of the workbench surface decreases, thereby avoiding heat backflow that could cause the soldering iron tip to heat up too quickly or waste power redundancy. When the fusion coefficient is lower than the second threshold, for example, less than 0.3, it is determined that the workbench surface is not heating enough, and the soldering iron tip needs to undertake more heating tasks. At this time, the output signal of the second PID controller is amplified according to the second proportional coefficient, for example, increased by 20% or more, to compensate for the overall insufficient heat flow and keep the solder joint temperature within the effective range. During the PID signal distribution process based on the heat flux structure, the actual current value of the soldering iron tip heating circuit is simultaneously acquired. This current value is collected by a Hall current sensor connected in series in the soldering iron tip power supply circuit, amplified by an operational amplifier, and digitally converted by an ADC before being fed back to the main control chip. Simultaneously with acquiring the real-time heating current, the peak current threshold is determined based on the rated power of the soldering iron tip being used. For example, a 60W soldering iron tip corresponds to 18A, 90W to 23A, and 120W to 28A. This threshold is then compared with the real-time current to calculate the current margin. The current margin reflects the margin remaining between the actual current and the peak safe upper limit. A small current margin indicates that the power output is approaching the equipment's tolerance limit. The current margin is divided into multiple control ranges, and a current limiting coefficient is configured for each range. For example, the current limiting coefficient is set to 0.85 when the margin is between 10% and 15%, 0.70 when it is between 5% and 10%, and 0.50 when it is below 5%, thus progressively strengthening protection. The current limiting coefficient is multiplicatively modulated with the second PID output signal to obtain the third PID output signal used to control the soldering iron tip heating circuit.

[0038] In one specific embodiment, the process of performing step 400 may specifically include the following steps: Calculate the difference between the second thermal conductivity coefficient of the current cycle and the second thermal conductivity coefficient of the previous cycle, and calculate the ratio of the difference to the second thermal conductivity coefficient of the previous cycle to obtain the rate of change of thermal conductivity coefficient; When the rate of change of thermal conductivity exceeds the preset rate of change threshold, it is determined that the solder melting has started and a control signal freeze command is triggered. Based on the control signal freeze command, the first PID output signal and the third PID output signal are locked to their current values ​​and maintained for the preset welding time.

[0039] Specifically, within each control cycle, the second thermal conductivity coefficient calculated for the current cycle is recorded, and the difference between the current second thermal conductivity coefficient and the second thermal conductivity coefficient of the previous cycle is calculated. This difference describes the degree of abrupt change in thermal conductivity per unit time. Dividing this difference by the second thermal conductivity coefficient of the previous cycle constructs a dimensionless rate of change of thermal conductivity coefficient, reflecting the degree of drastic change in thermal conductivity characteristics during the transition from solid to liquid state at the solder joint interface. When the rate of change of thermal conductivity coefficient exceeds a preset threshold, for example, a rate of change greater than 0.30, it indicates a significant jump in the second thermal conductivity coefficient compared to the previous cycle. This is because the solder reaches its melting point and begins to melt. The liquid solder fills the previously existing microscopic gaps, causing a sharp decrease in the contact thermal resistance of the solder joint, thereby improving the unit heat transfer efficiency. Based on this change pattern, it is determined that solder melting has begun, and a freeze command is triggered in the control signal. Based on the control signal freeze command, the output signal of the first PID controller, i.e., the heating power of the worktable, is maintained at a fixed value at the moment of freeze, and no longer responds to subsequent control error updates. Simultaneously, the output signal of the third PID controller, which has already undergone current-limiting modulation, i.e., the actual heating signal of the soldering tip, is also locked to the output value at the moment of freeze, maintaining the current thermal power state and providing a stable temperature environment for the solder to fully melt, flow, and wet the pads and pins. In the frozen state, the timing module starts running and maintains the frozen state of the first and third PID signals until the preset soldering time ends, for example, set to last 5 seconds. This time ensures that typical solder joints complete metal wetting and diffusion and stable formation of liquid solder, avoiding quality problems such as cold solder joints, bridging, or localized solder condensation caused by unstable thermal fields due to frequent fluctuations in the control signal. After the freeze time ends, the lock is automatically released, the PID controller's response to real-time errors is restored, and the thermal flow scheduling and current-limiting protection logic is restarted.

[0040] In one specific embodiment, the process of performing step 500 may specifically include the following steps: Calculate the cooling rate of the PCB substrate temperature, determine whether the cooling rate is within the preset cooling rate range, and obtain the cooling rate deviation status; When the cooling rate deviation state is too fast, the first PID output signal is increased to raise the target temperature of the platform; when the cooling rate deviation state is too slow, the first PID output signal is decreased. The electrostatic voltage of the workbench surface is collected. When the electrostatic voltage of the workbench surface exceeds the preset electrostatic threshold, the third PID output signal is current limited. When the leakage current exceeds the preset leakage current threshold, the heating is turned off.

[0041] Specifically, a dynamic cooling rate control mechanism based on the PCB substrate temperature change trend is introduced. The PCB surface temperature is continuously collected every second, and the instantaneous cooling rate is calculated by combining the temperature values ​​from two consecutive sampling times. The cooling rate is defined as the rate of temperature decrease of the PCB substrate per unit time, reflecting the speed of the current cooling process. The cooling rate is compared with a preset ideal cooling rate range, for example, a decrease of 5°C to 8°C per second, to cover the cooling rate range required for uniform release of thermal stress during typical solder joint solidification. Based on this, it is determined whether the current cooling rate is within the range; if it deviates from this range, it is marked as a cooling rate deviation. When the cooling rate deviation is determined to be too fast, i.e., the temperature drop rate exceeds the upper limit of 8℃ / s, it indicates that the heat loss is too rapid, leading to uneven solder shrinkage, solder joint structural cracking, or residual stress accumulation inside the components. In this case, the output signal of the first PID controller is increased to adjust the target temperature of the worktable accordingly, thereby releasing some heat through the worktable to slow down the overall cooling trend and achieve thermal buffering. If the cooling rate deviation is determined to be too slow, i.e., the temperature drop rate is below the lower limit of 5℃ / s, it indicates that the heat retention time is too long, causing solder grain coarsening and the solder joint solidification process to be disturbed. In this case, the output signal of the first PID controller is decreased to lower the target temperature of the worktable, thereby accelerating the heat dissipation process to restore a reasonable cooling path. Simultaneously, the voltage value of the workbench surface to ground is collected in parallel to detect the static electricity accumulation level in real time. The voltage sampling is fed back to the main control chip by the static electricity detection circuit at fixed time intervals. When the static electricity voltage of the workbench surface exceeds a set threshold, such as 200V, it is determined that there is a risk of excessive static electricity. In order to avoid damage to sensitive devices by electrostatic discharge, current limiting processing is performed on the third PID output signal, and the current heating control signal is proportionally attenuated to a safe output level, such as multiplied by 0.3, so that the heating power of the soldering iron tip is kept at a very low state to reduce electrical field disturbance. The leakage current status is monitored by the integrated power protection module, and the current difference between the live wire and the neutral wire is continuously sampled. When the detected value exceeds 30mA and lasts for more than 50ms, the heating shutdown operation is performed. Specifically, this includes pulling down the gate voltage of the control IGBT to the cutoff state and disconnecting the solid-state relay, thereby completely cutting off the power supply to the workbench heating and the soldering iron tip, and the whole machine enters a forced shutdown protection state.

[0042] Specifically, when the cooling rate deviation is too fast, the first PID output signal is increased to raise the target temperature of the cooling platform; when the cooling rate deviation is too slow, the first PID output signal is decreased. This includes: setting a multi-level stepped cooling target temperature sequence, which includes a first-level target temperature, a second-level target temperature, and a natural cooling target temperature, and configuring a step maintenance time for each level of the target temperature; reducing the target temperature of the cooling platform controlled by the first PID controller from the current preheating temperature to the first-level target temperature; monitoring the PCB substrate temperature and calculating the first-stage cooling rate; and when the first-stage cooling rate exceeds the preset cooling rate... When the cooling rate is within the preset range, adjust the first PID output signal to maintain the first-step target temperature until the step maintenance time ends; reduce the target temperature of the platform from the first-step target temperature to the second-step target temperature, monitor the PCB substrate temperature and calculate the second-stage cooling rate. When the second-stage cooling rate exceeds the preset cooling rate range, adjust the first PID output signal to maintain the second-step target temperature until the step maintenance time ends; after the second-step target temperature maintenance is completed, turn off the first PID controller to enter the natural cooling stage, continuously monitor the cooling rate of the PCB substrate temperature, and ensure that the cooling rate is always within the preset cooling rate range throughout the entire cooling process.

[0043] In this embodiment, before allocating the first PID output signal and the second PID output signal according to the thermal conductivity fusion coefficient, the method further includes: establishing a temperature prediction model based on the thermal conductivity equation. The temperature prediction model predicts the soldering tip temperature evolution trajectory and the substrate temperature evolution trajectory within a preset time window based on the first PID output signal, the second PID output signal, the thermal conductivity fusion coefficient, and the system thermal inertia parameters of the current period. The system thermal inertia parameters include the workbench heat capacity, the soldering tip heat capacity, and the thermal conductivity time constant. A predictive optimization objective function is constructed, including a tracking error term, an output smoothing term, and a temperature constraint penalty term. The tracking error term is calculated based on the cumulative deviation between the soldering tip temperature evolution trajectory and the soldering tip target temperature. The output smoothing term is calculated based on the gradient of the changes in the first PID output signal and the second PID output signal. The temperature constraint penalty term is based on whether the substrate temperature evolution trajectory exceeds the component's safe temperature. The penalty value is calculated based on the range. When the predicted substrate temperature exceeds the safe temperature range of the component, the penalty weight is increased according to the magnitude of the exceedance. An offline multi-condition parameter database is established, which stores the optimized parameter combinations corresponding to different thermal conductivity fusion coefficient ranges and different component types. The optimized parameter combinations include the prediction time window length, control update cycle, and PID output limiting coefficient. The optimized parameter combinations are obtained by iteratively optimizing the predictive optimization objective function through a genetic algorithm. Based on the current thermal conductivity fusion coefficient and the type of component to be repaired, the matching optimized parameter combinations are queried from the multi-condition parameter database. When the thermal conductivity fusion coefficient is between two storage intervals, interpolation calculation is performed on adjacent optimized parameter combinations. Based on the optimized parameter combinations obtained by querying or interpolation, the output limiting coefficients of the first PID controller and the second PID controller are set, and the PID output allocation adjustment is performed according to the control update cycle.

[0044] The intelligent temperature-controlled rework soldering method in the embodiments of this application has been described above. The intelligent temperature-controlled rework soldering device in the embodiments of this application is described below. Please refer to [link / reference]. Figure 2 One embodiment of the intelligent temperature-controlled rework soldering device in this application includes: The data acquisition module 11 is used to acquire the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate, and to calculate the first thermal conductivity coefficient between the workbench and the soldering iron tip and the second thermal conductivity coefficient between the soldering iron tip and the solder joint. Adjustment module 12 is used to adjust the target temperature of the platform based on the first thermal conductivity coefficient and the second thermal conductivity coefficient; The drive module 13 is used for the first PID controller to output a first PID output signal to drive the workbench to heat up according to the target temperature of the table, and the second PID controller to output a second PID output signal to drive the soldering iron tip to heat up and calculate the current margin to modulate the second PID output signal to obtain a third PID output signal. The maintenance module 14 is used to monitor the second thermal conductivity coefficient to determine the start of solder melting, and freeze the first PID output signal and the third PID output signal to maintain the preset welding time. The execution module 15 is used to control the cooling process by adjusting the cooling rate of the platform target temperature based on the PCB substrate temperature, and to perform current limiting or heating shutdown.

[0045] Please see Figure 3 , Figure 3 The present invention provides a schematic block diagram of the structure of an electronic device 300. The electronic device 300 includes a processor 301 and a memory 302, which are connected via a device bus 303. The memory 302 may include a non-volatile storage medium and internal memory.

[0046] The non-volatile storage medium can store a computer program. The computer program includes program instructions that, when executed by the processor 301, cause the processor 301 to perform any of the aforementioned intelligent temperature-controlled rework soldering methods.

[0047] The processor 301 provides computing and control capabilities to support the operation of the entire electronic device 300.

[0048] The internal memory provides an environment for the execution of computer programs in non-volatile storage media. When the computer program is executed by the processor 301, the processor 301 can execute any of the above-mentioned intelligent temperature-controlled rework soldering methods.

[0049] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the electronic device 300 involved in the present application. The specific electronic device 300 may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0050] It should be understood that processor 301 can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Among these, a general-purpose processor can be a microprocessor or any conventional processor.

[0051] It should be noted that those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the electronic device 300 described above can be referred to the corresponding process of the aforementioned intelligent temperature control rework soldering method, and will not be repeated here.

[0052] This application also provides a computer-readable storage medium storing a computer program that, when executed by one or more processors, causes the one or more processors to implement the intelligent temperature-controlled rework soldering method provided in this application.

[0053] The computer-readable storage medium can be an internal storage unit of the electronic device 300 described in the foregoing embodiments, such as a hard disk or memory of the electronic device 300. The computer-readable storage medium can also be an external storage device of the electronic device 300, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., provided by the electronic device 300.

[0054] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0055] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an electronic device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0056] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A smart temperature-controlled rework soldering method, characterized in that, include: Collect the preheating temperature of the workbench, the real-time temperature of the soldering iron tip, and the temperature of the PCB substrate, and calculate the first thermal conductivity coefficient between the workbench and the soldering iron tip and the second thermal conductivity coefficient between the soldering iron tip and the solder joint. Specifically, this includes: collecting the preheating temperature of the workbench, the real-time temperature of the soldering tip, and the temperature of the PCB substrate; calculating a first thermal conductivity coefficient based on a first temperature difference between the real-time temperature of the soldering tip and the preheating temperature of the workbench, a first contact thermal resistance between the workbench and the soldering tip, and a sampling time interval; and calculating a second thermal conductivity coefficient based on a second temperature difference between the real-time temperature of the soldering tip and the temperature of the PCB substrate, a second contact thermal resistance of the solder layer, and the sampling time interval. Adjusting the target tabletop temperature based on the first thermal conductivity coefficient and the second thermal conductivity coefficient; specifically including: calculating a thermal conductivity fusion coefficient based on the ratio of the first thermal conductivity coefficient to the sum of the first thermal conductivity coefficient and the second thermal conductivity coefficient; determining that the tabletop preheating temperature is too high when the thermal conductivity fusion coefficient is greater than a first threshold, and determining that the tabletop preheating is insufficient when the thermal conductivity fusion coefficient is less than a second threshold; calculating the tabletop temperature adjustment amount based on the deviation of the thermal conductivity fusion coefficient from a preset ideal value and a preset adjustment coefficient; and adjusting the target tabletop temperature based on the reference tabletop temperature and the tabletop temperature adjustment amount. The first PID controller outputs a first PID output signal to drive the workbench to heat up according to the target temperature of the workbench. The second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal to obtain a third PID output signal. The second thermal conductivity coefficient is monitored to determine the start of solder melting, and the first PID output signal and the third PID output signal are frozen to maintain a preset welding time. The cooling process is controlled by adjusting the cooling rate of the PCB substrate to regulate the target temperature of the platform, and by performing current limiting or shutting off heating.

2. The intelligent temperature-controlled rework soldering method according to claim 1, characterized in that, The first PID controller outputs a first PID output signal to drive the workbench to heat up based on the target temperature of the workbench. The second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal, resulting in a third PID output signal, including: The first PID controller calculates the first control error between the target temperature of the work surface and the preheating temperature of the work surface, and outputs a first PID output signal based on the first control error to drive the work surface to heat up to the preheating temperature and stabilize it. The target temperature of the soldering iron tip is determined by looking up a table based on the type of component to be repaired. The second PID controller calculates the second control error between the target temperature of the soldering iron tip and the real-time temperature of the soldering iron tip. Based on the second control error, a second PID output signal is output to drive the soldering iron tip to heat up, and the heating rate of the soldering iron tip is monitored and controlled within the preset heating rate range. The first PID output signal and the second PID output signal are allocated according to the heat conduction fusion coefficient. The current margin is calculated based on the real-time heating current to obtain the current limiting coefficient, which is then used to modulate the second PID output signal to obtain the third PID output signal.

3. The intelligent temperature-controlled rework soldering method according to claim 2, characterized in that, The step of allocating the first PID output signal and the second PID output signal according to the thermal conductivity fusion coefficient, and modulating the second PID output signal with a current limiting coefficient based on the current margin calculated from the real-time heating current to obtain the third PID output signal includes: When the thermal conductivity fusion coefficient is greater than the first threshold, the first PID output signal is adjusted according to the first proportional coefficient; when the thermal conductivity fusion coefficient is less than the second threshold, the second PID output signal is adjusted according to the second proportional coefficient. The real-time heating current of the soldering iron tip heating circuit is collected, and the current margin is calculated based on the real-time heating current and the peak current threshold determined according to the power of the soldering iron tip. The current limiting coefficient is determined based on the current margin, and the second PID output signal is modulated based on the current limiting coefficient to obtain the third PID output signal.

4. The intelligent temperature-controlled rework soldering method according to claim 3, characterized in that, The step of monitoring the second thermal conductivity coefficient to determine the start of solder melting, and freezing the first PID output signal and the third PID output signal to maintain a preset welding time includes: Calculate the difference between the second thermal conductivity coefficient of the current cycle and the second thermal conductivity coefficient of the previous cycle, and calculate the ratio of the difference to the second thermal conductivity coefficient of the previous cycle to obtain the rate of change of thermal conductivity coefficient; When the rate of change of the thermal conductivity coefficient is greater than a preset rate of change threshold, it is determined that the solder melting has started and a control signal freeze command is triggered. Based on the control signal freeze command, the first PID output signal and the third PID output signal are locked to their current values ​​and maintained for the preset welding time.

5. The intelligent temperature-controlled rework soldering method according to claim 1, characterized in that, The cooling process, which controls the target temperature of the platform based on the cooling rate of the PCB substrate temperature, and performs current limiting or heating shutdown, includes: Calculate the cooling rate of the PCB substrate temperature, determine whether the cooling rate is within the preset cooling rate range, and obtain the cooling rate deviation state; When the cooling rate deviation state is too fast, the first PID output signal is increased to raise the target temperature of the platform; when the cooling rate deviation state is too slow, the first PID output signal is decreased. The electrostatic voltage of the workbench surface is collected. When the electrostatic voltage of the workbench surface exceeds the preset electrostatic threshold, current limiting is applied to the third PID output signal. When the leakage current exceeds the preset leakage current threshold, the heating is turned off.

6. An intelligent temperature-controlled rework soldering device, characterized in that, For performing the intelligent temperature-controlled rework soldering method as described in any one of claims 1-5, the intelligent temperature-controlled rework soldering device comprises: The data acquisition module is used to collect the preheating temperature of the workbench, the real-time temperature of the soldering tip, and the temperature of the PCB substrate, and to calculate the first thermal conductivity coefficient between the workbench and the soldering tip and the second thermal conductivity coefficient between the soldering tip and the solder joint. The adjustment module is used to adjust the target temperature of the platform based on the first thermal conductivity coefficient and the second thermal conductivity coefficient; The drive module includes a first PID controller and a second PID controller. The first PID controller outputs a first PID output signal to drive the workbench to heat up according to the target temperature of the workbench. The second PID controller outputs a second PID output signal to drive the soldering iron tip to heat up and calculates the current margin to modulate the second PID output signal to obtain a third PID output signal. The maintenance module is used to monitor the second thermal conductivity coefficient to determine the start of solder melting, and freeze the first PID output signal and the third PID output signal to maintain a preset welding time. The execution module is used to control the cooling process by adjusting the target temperature of the platform based on the cooling rate of the PCB substrate temperature, and to perform current limiting or heating shutdown.

7. An electronic device, characterized in that, The electronic device includes: a memory and at least one processor, wherein the memory stores instructions; The at least one processor invokes the instructions in the memory to cause the electronic device to perform the intelligent temperature-controlled rework soldering method as described in any one of claims 1-5.

8. A computer-readable storage medium storing instructions thereon, characterized in that, When the instruction is executed by the processor, it implements the intelligent temperature-controlled rework soldering method as described in any one of claims 1-5.

Images