Intelligent monitoring system in production and preparation of electronic products

Abstract

The invention relates to the technical field of electronic product production and preparation intelligent monitoring, and particularly discloses an intelligent monitoring system in electronic product production and preparation, which comprises a data acquisition module, a signal generation module, a thermal shock alarm module, a defect judgment module, an instruction interlocking module and a safety interval adjustment module, the chip mounter suction nozzle off-board height change value and the reflow soldering furnace heat transfer value are obtained, a three-dimensional space signal is constructed according to the change value, an alarm is triggered by combining the off-board height change rate when the heat exceeds the limit, and the cold welding defect is recognized by analyzing the off-board height sudden change and the heat speed increase. The instruction interlocking module realizes logic interlocking of alarm and defect signals, and finally dynamically expands a preset safety interval boundary based on a three-dimensional space signal data range of continuous qualified products; according to the method, through multi-dimensional data fusion and dynamic threshold adjustment, the welding defect omission ratio and the unnecessary shutdown frequency of a production line are remarkably reduced, and efficient operation of flexible manufacturing is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent monitoring of electronic product production and preparation, in particular to an intelligent monitoring system in electronic product production and preparation. BACKGROUND

[0002] In the field of electronic manufacturing, real-time monitoring of soldering defects in surface mount technology presents significant challenges. Traditional methods rely on discrete detection systems: temperature sensors only monitor the thermal field fluctuations of the soldering furnace, and optical detection equipment statically samples the solder joint morphology after soldering. This fragmented monitoring mode makes it difficult to accurately capture thermal shock and cold soldering defects, as the dynamic correlation between physical displacement and thermal state changes is not effectively analyzed. In actual production, a single temperature overrun or component displacement is often misjudged as a real defect, or hidden faults are missed due to detection lag, resulting in high product rework rates.

[0003] Conventional solutions use independent threshold judgment mechanisms. The temperature monitoring system sets a fixed safety interval, and an overrun triggers an alarm; the mechanical monitoring module determines placement abnormalities based on a pre-set height change threshold. The two systems run in parallel but there is no data interaction, and the alarm logic only relies on single-dimensional signals.

[0004] The traditional discrete monitoring mode has inherent drawbacks. First, the false alarm rate is significantly increased, as temperature transient fluctuations or mechanical vibrations may be incorrectly identified as defects, leading to frequent unnecessary downtime on the production line. Second, the detection rate of hidden defects such as cold soldering is high, as there is a lack of coordinated analysis of heat accumulation rate and component displacement. Third, manual recalibration of system thresholds is required when the production line is changed, resulting in long debugging periods and the introduction of human errors. SUMMARY

[0005] In view of this, to solve the problems raised in the background art, an intelligent monitoring system in electronic product production and preparation is proposed.

[0006] The purpose of the present application can be achieved by the following technical solutions: The present application provides an intelligent monitoring system in electronic product production and preparation, comprising: a data acquisition module that acquires the off-board height change value collected by a miniature distance measuring device on the side of the suction nozzle of a chip mounter, and acquires the heat transfer values recorded by a temperature sensor array in the heating area of a reflow soldering furnace at a preset period.

[0007] A signal generation module that time-synchronizes and merges the off-board height change value and the heat transfer value to generate a three-dimensional space signal containing the physical position of the component and the temperature state.

[0008] The heat shock alarm module extracts the off-board height change value at the corresponding time point when the heat transfer value exceeds the preset safety interval, calculates the off-board height change rate, triggers the welding heat shock alarm if the off-board height change rate exceeds the stable threshold, and marks the temperature data interference otherwise.

[0009] The defect determination module calculates the heat increase rate when the off-board height change value has a discontinuous mutation, determines the cold welding defect if the heat increase rate is lower than the solder paste melting critical value, and marks the mechanical collision anomaly if the heat increase rate is normal but the height mutation is continuous.

[0010] The instruction interlocking module logically interlocks the welding heat shock alarm and the cold welding defect determination signal: outputs the release instruction when neither of them is activated, and outputs the stop instruction when either of them is activated.

[0011] The safety interval adjustment module calculates the three-dimensional space signal data range of a continuous preset number of qualified products, and generates a floating margin safety interval based on the data range to expand the boundary of the preset safety interval.

[0012] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects: (1) The present application fuses the dynamic change of the off-board height of the element and the heat transfer data of the welding point in real time, constructs a three-dimensional space signal model, and the system can capture the synergistic effect of physical displacement and heat state change. The transient interference and the real defect that cannot be distinguished by traditional single-dimensional monitoring are accurately decoupled under this model. The determination of the cold welding defect combines the heat accumulation rate and the timing relationship of the height mutation, and solves the problem of hidden fault missed detection.

[0013] (2) The present application dynamically adjusts the monitoring threshold based on the historical data of continuous qualified products, breaks through the limitations of the traditional fixed parameter mode. The safety interval boundary automatically expands the floating margin according to the actual working condition, which not only tolerates equipment tolerance and material batch difference, but also maintains the quality monitoring sensitivity. When the product model is switched on the production line, there is no need for manual parameter calibration, which significantly shortens the debugging period. This mechanism enables the monitoring system to continuously match the process changes, eliminates the risk of misjudgment caused by rigid threshold, and guarantees the efficient operation of flexible manufacturing.

[0014] (3) The present application cross- validates the heat shock alarm and the cold welding defect determination signal, and only allows the product to circulate when neither of them is activated. Any abnormal signal triggers the precise stop of the station level, and synchronously locates the fault coordinates. This design breaks through the limitations of traditional parallel independent alarm, avoids unnecessary downtime caused by single-dimensional misjudgment. At the same time, the defect determination is forced to meet the compound condition, which greatly reduces the missed detection rate. The production line reduces the frequency of unnecessary downtime while ensuring the interception rate, realizing the synergistic optimization of quality control and production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 It is a schematic diagram of the system module structure of the present application.

[0017] Figure 2 It is a schematic diagram of the heat speed-up calculation process of the present application.

[0018] Figure 3 It is a logic interlocking analysis flowchart of the present application. DETAILED DESCRIPTION

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

[0020] Please refer to Figure 1 The present application provides an intelligent monitoring system in electronic product production preparation, comprising: a data acquisition module, a signal generation module, a thermal shock alarm module, a defect determination module, an instruction interlocking module and a safety interval adjustment module.

[0021] The data acquisition module is connected with the signal generation module, the signal generation module is connected with the thermal shock alarm module and the defect determination module respectively, the thermal shock alarm module and the defect determination module are connected with the instruction interlocking module, and the safety interval adjustment module is connected with the signal generation module.

[0022] The data acquisition module acquires the off-board height change value collected by the micro distance measuring device on the side of the suction nozzle of the chip mounter in real time, and acquires the heat transfer value recorded by the temperature sensor array of the reflow soldering furnace heating area at a preset period.

[0023] In the specific embodiment of the present application, the specific acquisition method of the off-board height change value is that the micro distance measuring device is installed in the non-functional interference area of the outer wall of the suction nozzle of the chip mounter.

[0024] During the movement of the adsorbed electronic element, the micro distance measuring device continuously measures the dynamic change value of the distance between the bottom of the element and the surface of the circuit board pad.

[0025] The distance dynamic change value is transmitted as a height change value data stream from the board through a preset communication protocol.

[0026] It should be noted that this step is realized in the process of assembling electronic components by a patch machine. First, a miniature distance measuring device, such as a device based on the laser triangulation distance measuring principle, is firmly installed on the designated side of the outer wall of the suction nozzle of the patch machine. The installation position needs to avoid the vacuum channel and the component contact surface of the suction nozzle to ensure that the suction function is not disturbed during the operation of the suction nozzle. When the patch machine starts to adsorb the electronic component and lowers it to the surface of the circuit board pad, the miniature distance measuring device continuously emits a probe light beam to irradiate the bottom area of the component, and simultaneously receives the echo signal reflected from the surface of the pad or the component. The instantaneous distance value between the bottom of the component and the circuit board pad is calculated according to the signal return time. During the entire period of the patching operation, the continuous dynamic change process of the distance is recorded in real time, thereby obtaining the complete data stream of the height change value from the board. The data is transmitted in real time to the subsequent processing device through a standard interface such as the RS-485 protocol, forming the basis input of the monitoring signal.

[0027] It should be further noted that the suction nozzle of the patch machine refers to the vacuum suction mechanism of the patch machine device responsible for adsorbing and placing electronic components, and the standard structural design of the patch machine is used to realize the grabbing and releasing of the components. The side installation refers to the operation position of the miniature distance measuring device fixed on the outer wall of the suction nozzle, and the setting basis is to avoid interfering with the normal work of the suction nozzle, while using the rigid outer wall of the suction nozzle to provide a stable mounting point. The miniature distance measuring device refers to a technical device with a size smaller than the diameter of the suction nozzle and using non-contact detection. The setting basis is the spatial limitation of the patch environment and the requirement of high-speed operation, and the type selection needs to have millimeter-level precision to adapt to the size of electronic components. The adsorbed state of the electronic component refers to the working condition during the process of moving the component suspended in the air after being adsorbed by the suction nozzle of the patch machine. The setting basis is the standard process of patching operation, covering the complete action from picking up the component to completing the placement. The height change value from the board refers to the continuous signal directly output by the miniature distance measuring device, indicating the dynamic change of the distance between the bottom plane of the component and the surface of the circuit board pad. The setting basis is that the change can reflect the stability and deviation of the component placement, and the fluctuation of the real-time distance value represents the dynamic characteristics of the physical action. The distance dynamic change value between the bottom of the component and the surface of the circuit board pad is the complete definition term of the quantity, and the setting basis is to clearly describe the spatial position relationship between the component and the pad to ensure the accuracy of the monitoring.

[0028] In specific embodiments of the present application, the specific acquisition method of the heat transfer value is to arrange a temperature sensor array on the inner wall of the furnace cavity of the key heating zone of the reflow soldering furnace.

[0029] When the transmission guide rail carrying the circuit board passes through, the environmental temperature of the solder joint position is collected at a preset sampling frequency.

[0030] The collected temperature data is converted into a standard voltage signal to generate time-sequenced heat transfer values.

[0031] It should be noted that after the acquisition of the off-board height variation value is completed, the physical contact temperature sensor array is immediately installed on the surface of the multiple heating areas inside the reflow soldering furnace; the array is composed of a plurality of thermocouples arranged closely, and the temperature sensing end of each thermocouple is firmly attached to the surface of the metal shell at a specified point directly above the guide rail in the furnace; the arrangement density needs to ensure that the thermal field state of the solder joint position is completely covered; when the transmission guide rail carrying the circuit board passes through the heating area, all the thermocouples continuously collect the temperature values of the heat source transferred to the solder joint position at a rate of 0.1 seconds per second; the obtained data is transmitted to the signal converter through insulated wires to be converted into a standard voltage signal; the signal is transmitted in real time to the data processor through a shielded cable to form a sequence of heat transfer values; the sequence is kept in synchronization with the off-board height variation value by a unified clock source.

[0032] It should be further noted that the heating area of the reflow soldering furnace refers to the sealed cavity space in the electronic assembly equipment that realizes soldering through thermal radiation or heat convection, and the setting basis is that the heat transfer in this area directly affects the solder paste melting process; the temperature sensor array refers to a temperature monitoring component formed by arranging three or more thermocouples in a rectangular grid, and the setting basis is to cover the maximum size of the circuit board and eliminate the monitoring blind area; the arrangement refers to fixing the thermocouple sensing head on the top position of the inner wall of the furnace cavity through high-temperature adhesive tape or buckle, and the setting basis is to detect the environmental temperature field closest to the solder joint; the solder joint position refers to the physical connection point formed by the contact between the pins of the electronic component to be soldered and the pad on the circuit board, and the setting basis is the core quality control part of the soldering process; recording once every 0.1 seconds refers to a periodic measurement operation repeatedly performed at a fixed time interval, and the setting basis is to match the sensitive period of temperature change during soldering of the electronic component; the heat transfer value refers to the temperature scale data stream converted from the voltage signal actually measured by the thermocouple, and the setting basis is to accurately reflect the energy state transferred from the heat source to the solder joint; the value is a key thermal field characteristic parameter for subsequent analysis.

[0033] The signal generation module time-synchronously merges the off-board height variation value and the heat transfer value to generate a three-dimensional space signal containing the physical position of the component and the temperature state.

[0034] In specific embodiments of the present application, the specific process of time-synchronous merging is to use a unified clock source to mark the time stamps of the off-board height variation value and the heat transfer value.

[0035] The component space coordinates are obtained through the movement trajectory of the feeding mechanism of the chip mounter.

[0036] The off-board height variation value, the heat transfer value and the space coordinates with the same time stamp are associated to construct the data structure of the three-dimensional space signal.

[0037] It should be noted that, on the basis of obtaining the off-board height change value and the heat transfer value, the two data sequences are synchronized by using a unified clock signal source; the clock signal is input to the distance measuring device of the chip mounter and the temperature acquisition system of the soldering furnace respectively; a programmable logic controller is used to establish a time reference, which is triggered when the circuit board enters the reflow soldering furnace; the collected off-board height change values are arranged in time sequence, and the collected heat transfer values are sorted in the same time sequence; the height change value and the temperature value at the same time point are combined into a two-dimensional data set; on this basis, spatial position coordinate information is added; the position coordinates are obtained by calculating the movement trajectory of the chip mounter feeding mechanism; finally, a three-dimensional space signal composed of time axis, height change value and heat transfer value is formed; the signal is transmitted in real time to the diagnosis terminal through the industrial bus.

[0038] It should be further noted that time synchronization and merging refers to the alignment operation of making the data generated by different devices have a unified time scale, and the setting basis is to ensure the correlation of the movement state and the thermal state at the same time; the off-board height change value is the continuous distance dynamic change sequence collected by the micro distance measuring device during the adsorption process, and the setting basis is to reflect the spatial displacement characteristics of the component installation; the heat transfer value is the temperature data stream measured by the temperature sensor array at fixed intervals, and the setting basis is to represent the energy transfer state of the soldering process; generation refers to the process of forming a new information carrier through data processing; the physical position of the component refers to the instantaneous coordinate point of the electronic component in the three-dimensional space, and the setting basis is the position feedback provided by the displacement sensor of the mechanical arm of the chip mounter feeding system; the temperature state refers to the heat intensity value borne by the solder joint position at that time; the three-dimensional space signal refers to a three-dimensional data structure constructed by time dimension, height change dimension and temperature value dimension, and the setting basis is to completely describe the space-time state evolution of the electronic component in the soldering process; the signal is used as the basic analysis object for subsequent diagnosis.

[0039] The heat shock alarm module, when the heat transfer value exceeds the preset safe interval, extracts the off-board height change value at the corresponding time point to calculate the off-board height change rate, and if the off-board height change rate exceeds the stable threshold, a soldering heat shock alarm is triggered, otherwise it is marked as temperature data interference.

[0040] It should be noted that the preset safe interval is set as a closed interval composed of the lower limit temperature value and the upper limit temperature value determined by the characteristics of the solder paste material.

[0041] In one embodiment of the present application, the stable threshold is an acceptable deviation boundary set according to the mechanical vibration amplitude of the chip mounter and the component specifications, and the setting basis is the physical characteristics of the equipment and the component tolerance data, which can be specifically valued at 0.8 mm / s.

[0042] In specific embodiments of the present application, the specific way of calculating the off-board height change rate is: extracting the off-board height change values of adjacent sampling points before and after the time point when the heat transfer value exceeds the threshold.

[0043] Calculating the sum of the absolute values of the difference values of the off-board height changes of adjacent sampling points.

[0044] Dividing the sum of the absolute values of the difference values by the sampling time step to generate the off-board height change rate.

[0045] It should be noted that when the real-time acquired heat transfer value exceeds the upper or lower limit of the preset safety interval, the abnormal time point is automatically locked; the off-board height change values of the current and adjacent two sampling points are immediately extracted; the absolute values of the difference values of the off-board height changes between adjacent time points are calculated; the sum of the two absolute values of the difference values is divided by the time step to obtain the off-board height change rate of the time point; the rate is compared with the stability threshold value; if the rate calculation result exceeds the stability threshold value, a welding thermal shock warning signal is sent to the production line control system; if the rate calculation result does not exceed the stability threshold value, this abnormality is classified as a temperature data interference event in the log record; the whole process is completed within 0.1 seconds to ensure real-time response.

[0046] It should be further noted that the heat transfer value refers to the temperature sensor array collecting and via the above-mentioned synchronized heat field characteristic parameters; exceeding the preset safety interval refers to the value exceeding the temperature operating space range set according to the solder paste melting characteristics, and the setting basis is the solder paste heat bearing capacity standard in the soldering process quality specification; immediate inspection refers to the system automatically interrupting the current execution thread and preferentially processing the immediate response mechanism of the event; the time point corresponds to the timestamp marker position of the three-dimensional space signal; the off-board height change trend refers to the element height change direction and amplitude characteristics recorded by the miniature distance measuring device before and after the abnormal time point; the off-board height change rate refers to the fluctuation amplitude of the off-board height change value per unit time, and the setting basis is the dynamic stability reflecting the element heating state; triggering the welding thermal shock warning refers to sending a red priority warning containing a position code to the central control system; marking as temperature data interference refers to recording the event in the historical database with a specific code but not triggering the equipment shutdown action.

[0047] For example, when the circuit board passes through the third temperature zone by reflow soldering, the heat transfer value of 245℃ is recorded at 15.3 seconds; the upper limit of the preset safety interval is 240℃; the system immediately extracts the off-board height change values of 0.15 mm, 0.18 mm and 0.35 mm at 15.2 seconds, 15.3 seconds and 15.4 seconds respectively; the height difference is calculated as 0.03 mm and 0.17 mm; the sum of 0.20 mm is divided by the time step of 0.2 seconds to obtain the change rate of 1.0 mm / s; the stability threshold set by the equipment at the factory is 0.8 mm / s; therefore, it is determined that the change rate calculation result exceeds the stability threshold; the system immediately triggers the welding thermal shock alarm with coordinate positioning; the alarm is displayed on the control screen and the alarm is flashing; if the height change rate calculation result is 0.5 mm / s under the same temperature anomaly, which is lower than the threshold, only the "third temperature zone sensor interference event" is recorded in the database.

[0048] The defect determination module calculates the heat increase rate from the heat transfer value sequence of the previous preset length when the off-board height change value has a non-continuous mutation; if the heat increase rate is lower than the critical value of solder paste melting, a cold soldering defect is determined; if the heat increase rate is normal but the height mutation is continuous, a mechanical collision anomaly is marked.

[0049] In an embodiment of the present application, the non-continuous mutation of the off-board height change value refers to that the absolute value of the difference between the off-board height change values of two adjacent sampling points is greater than a specific multiple of the historical fluctuation mean value.

[0050] In an embodiment of the present application, the specific multiple is set to three times according to the vibration characteristics of the equipment.

[0051] Please refer to Figure 2 In an embodiment of the present application, the specific way of calculating the heat increase rate is to identify the time point of the non-continuous mutation of the off-board height change value.

[0052] The heat transfer value sequence of the previous preset backtracking length is extracted.

[0053] The sum of the temperature increment per unit time in the sequence is calculated to generate the heat increase rate.

[0054] It should be noted that the recognition mechanism of discontinuous mutation is set to be greater than three times the absolute value of the historical fluctuation mean of the height difference between the adjacent two sampling points; when the mutation at a certain time point is detected, the heat transfer value sequence in the two second time window before the time point is automatically called; all temperature data points in the sequence are extracted; the increment change between the temperature data points is calculated; the increment sum is divided by the length of the time window to obtain the heat increase rate value; the value is compared with the solder paste melting critical value: if the heat increase rate calculation result is lower than the critical value, a cold solder defect judgment signal is sent to the quality system; if the heat increase rate is above the critical value but the height difference keeps abnormal fluctuation in the subsequent three sampling points, the system marks the mechanical collision abnormal event code in the equipment log.

[0055] It should be further pointed out that the backtracking analysis refers to the operation mode of the system tracing back the historical data, and the time window is set to two seconds before the mutation time (the setting basis is the minimum heat accumulation time required for solder paste melting); the two seconds refer to the time period of two seconds from the mutation time point (including the starting point of the mutation time); the specific time period data is obtained through the time axis index; the solder paste melting critical value is the minimum temperature rise rate set according to different solder paste specifications, and the specific value is derived from the solder supplier technical manual; the cold solder defect refers to the fault state that the solder is not completely fused due to insufficient heat; the normal heat increase rate refers to that the heat increase rate calculation result is not lower than the solder paste melting critical value; the mechanical collision abnormality refers to the unintended displacement caused by the interference of the equipment parts (the marking basis is the continuous height abnormality after excluding the heat factor).

[0056] For example, in the production process of the circuit board, the height difference from the board is detected to increase from 0.12 mm to 0.48 mm (more than three times the historical fluctuation amplitude) at 08:15:36.200 seconds; the system immediately extracts the heat transfer value sequence during 08:15:34.200 to 08:15:36.200 seconds (10 data points per second); the temperature increment sum in the window is calculated to be 6°C, and the heat increase rate is 3°C per second by dividing by two seconds; the melting critical value of the lead-free solder paste used in the solder wire is 3.5°C per second, so it is determined that the heat increase rate is insufficient; at this time, the system triggers the cold solder defect judgment signal and suspends the flow of the circuit board to the next station. In another scenario, when the height mutation value occurs at the X72-Y85 position, the heat increase rate in the two second window reaches 4.2°C per second (higher than the critical value), but the height values of the subsequent three sampling points continuously deviate to 0.51 mm, 0.49 mm and 0.53 mm (20% higher than the reference value), and the system records the "X72-Y85 mechanical collision event code" in the maintenance account, prompting the maintenance of the transmission rail.

[0057] The instruction interlocking module logically interlocks the welding thermal shock alarm and the cold welding defect determination signal: outputs a release instruction when both are not activated, and outputs a stop instruction when either is activated.

[0058] Referring to Figure 3 In the embodiment of the present application, the specific analysis process for logical interlocking is: real-time monitoring of the activation state of the welding thermal shock alarm signal and the cold welding defect determination signal.

[0059] When both signals are in the unactivated state, a release pulse signal is sent to the conveyor belt controller.

[0060] When either signal is in the activated state, a stop current is output to the pneumatic brake device.

[0061] It should be noted that after obtaining the welding thermal shock alarm signal and the cold welding defect determination signal, an independent double-channel signal monitoring thread is established; the activation state of the two signals is scanned in real time; the interlocking determination period is set to be the shortest time required for one station in the production line to be transported; the flag bit of the two types of signals is checked at the beginning of each determination period; only when the thermal shock alarm flag bit remains in the unactivated state and the cold welding defect determination signal flag bit also remains in the unactivated state, a direct current pulse release instruction is sent to the conveyor motor controller; if it is detected that any signal flag bit is in the activated state, a 24-volt direct current stop current is immediately sent to the pneumatic brake device; the stop action also causes the current station alarm indicator light to turn red and become constantly on; the interlocking determination result is updated to the central monitoring interface through industrial Ethernet; the delay from signal acquisition to execution action is controlled within 0.2 seconds.

[0062] It should be further noted that the logical interlocking refers to a control mechanism for cross-verification of the welding thermal shock alarm signal, and the execution principle is "release when both are normal, stop when there is an exception"; both the thermal shock alarm and the cold welding defect being unactivated means that at the determination moment, the flag bits of both signals are in the logical low level state (0 value); any signal being activated means that at least one flag bit of the two types of signals is in the logical high level state (1 value).

[0063] For example, in the monitoring process of circuit board No. D004, it is monitored that the heat transfer value exceeds the threshold but the height change rate from the board does not exceed the threshold (marked as temperature data interference, alarm unactivated); no discontinuity mutation is detected (cold welding defect signal unactivated); the system determines that both are in the unactivated state within a 0.1 second period; a release pulse is immediately sent to the conveyor belt controller, and the circuit board is normally transported to the functional test station. When circuit board E005 passes through, the heat increase rate is detected to be lower than the threshold value at the X15-Y60 position (cold welding defect determination signal activated); although the alarm is unactivated, the system detects that the cold welding signal flag bit is 1; a stop instruction is immediately triggered.

[0064] The safety interval adjustment module, statistics continuous pre-set number of qualified products the three-dimensional space signal data range, based on the data range expansion the preset safety interval boundary generates floating margin safety interval.

[0065] Need to explain, the continuous pre-set number of qualified products refers to the final function test and does not trigger the circuit board product of cutting stop instruction, pre-set number setting basis is the lower limit of the base of statistical significance requirement, in a specific embodiment of the application, the pre-set number can take 20 pieces.

[0066] In a specific embodiment of the application, the specific process of generating floating margin safety interval is: extracting the heat transfer value extreme value in the three-dimensional space signal of qualified products.

[0067] The preset proportion of the original safety interval width floating margin expansion amount is calculated.

[0068] In a specific embodiment of the application, the specific way of calculating the preset proportion of the original safety interval width floating margin expansion amount is: obtaining the upper boundary value and the lower boundary value of the preset safety interval.

[0069] The absolute difference value of the upper boundary value and the lower boundary value is calculated to generate the original safety interval width.

[0070] The original safety interval width is multiplied by a preset expansion coefficient to obtain a floating margin expansion amount.

[0071] The floating margin expansion amount is added to the original boundary to generate a floating margin safety interval.

[0072] Need to explain, after the circuit board product completes all monitoring processes and passes the final function test, the system automatically identifies the record of continuous pre-set number of qualified products; call these qualified products in the generated whole three-dimensional space signal historical data set; for the three-dimensional space signal of each product, respectively extract the off-board height change value sequence and the heat transfer value sequence; statistics of the off-board height change value distribution interval and the heat transfer value distribution interval of each time point in the overall data set; the upper boundary value and the lower boundary value of the preset safety interval are respectively executed boundary expansion calculation operation; the upper boundary original value is added to the interval width and the product of the expansion proportion parameter as the new upper boundary value; the lower boundary original value is subtracted from the interval width and the product of the expansion proportion parameter as the new lower boundary value; the new boundary value group calculated is updated as the expansion safety interval used for subsequent product monitoring.

[0073] It is further needed to be explained that the three-dimensional space signal refers to a data structure containing time axis, off-board height change value, and heat transfer value; data range refers to the value distribution space of each parameter in the three-dimensional space signal (continuous interval from minimum value to maximum value); safety interval boundary refers to the preset upper and lower limit values of the safety interval used (i.e. the allowed running range boundary of the heat transfer value); expansion ratio parameter refers to the intermediate value of the electronic manufacturing experience value, in a specific embodiment of the present application, the value is 15%; interval width refers to the numerical difference between the upper and lower boundaries of the original safety interval.

[0074] For example, during the production batch switching of the circuit board, the system selects the last 20 qualified circuit boards; extracts the three-dimensional space signal data of these circuit boards from the database; the original safety interval of the heat transfer value of the position point X50-Y60 is set to 240-250℃; the actual running interval obtained by the statistics of the position point is 239.8-249.7℃; the system calculates the original interval width to be 10℃; according to the 15% floating margin requirement, the expansion value is 1.5℃; the new upper boundary becomes 251.5℃, and the new lower boundary becomes 238.5℃; at the same time, the original setting of the stable threshold of the off-board height change value of the position point is 0.8mm / s; after the same mechanism expansion, it is updated to 0.92mm / s; these updated parameters are automatically loaded into the monitoring system of the new batch of the same type of products.

[0075] The above is only an example and explanation of the concept of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the concept of the present application or exceed the scope defined by the present application, which shall belong to the protection scope of the present application.

Claims

1. An intelligent monitoring system in the production of electronic products, characterized by, The method comprises the following steps: A data acquisition module acquires the off-board height change value collected by a miniature distance measuring device on the side of a patch machine suction nozzle in real time and acquires the heat transfer value recorded by a temperature sensor array in a preset period in a heating area of a reflow soldering furnace; A signal generation module synchronously combines the off-board height change value and the heat transfer value to generate a three-dimensional space signal containing the physical position and temperature state of the component; A thermal shock alarm module calculates the off-board height change rate by extracting the off-board height change value at the time point when the heat transfer value exceeds the preset safety interval, and triggers a welding thermal shock alarm if the off-board height change rate exceeds the stable threshold, otherwise, it is marked as temperature data interference; A defect judgment module calculates the heat increase rate by backtracking the heat transfer value sequence in the previous preset period when the off-board height change value has a non-continuous mutation, and judges a cold welding defect if the heat increase rate is lower than the critical value of solder paste melting, or marks a mechanical collision anomaly if the heat increase rate is normal but the height mutation is continuous; An instruction interlocking module logically interlocks the welding thermal shock alarm and the cold welding defect judgment signal: outputs a release instruction when neither of them is activated, and outputs a stop instruction when either of them is activated; A safety interval adjustment module expands the boundary of the preset safety interval based on the data range of the three-dimensional space signal of a continuous preset number of qualified products to generate a floating margin safety interval.

2. The intelligent monitoring system in the production of electronic products according to claim 1, characterized in that: The specific acquisition method of the off-board height change value is as follows: Install the miniature distance measuring device on the non-functional interference area of the outer wall of the patch machine suction nozzle; During the movement of the adsorbed electronic component, continuously measure the dynamic change value of the distance between the bottom of the component and the surface of the circuit board pad through the miniature distance measuring device; Convert the distance dynamic change value into an off-board height change value data stream through a preset communication protocol.

3. The intelligent monitoring system in the production of electronic products according to claim 1, characterized in that: The specific acquisition method of the heat transfer value is as follows: Arrange a temperature sensor array on the inner wall of the furnace cavity in the key heating area of the reflow soldering furnace; When the transmission rail carrying the circuit board passes through, collect the environmental temperature of the solder joint position at a preset sampling frequency; Convert the collected temperature data into a standard voltage signal to generate a time-sequenced heat transfer value.

4. The intelligent monitoring system in the production of electronic products according to claim 1, characterized in that: The specific process of time synchronization and combination is as follows: Use a unified clock source to mark the time stamp of the off-board height change value and the heat transfer value; Obtain the spatial coordinates of the component through the movement trajectory of the patch machine feeding mechanism; Correlate the off-board height change value, heat transfer value and spatial coordinates with the same time stamp to construct the data structure of the three-dimensional space signal.

5. The intelligent monitoring system in the production of electronic products according to claim 1, characterized in that: The specific method of calculating the off-board height change rate is as follows: Extract the off-board height change values of the adjacent sampling points before and after the time point when the heat transfer value exceeds the standard; Calculate the sum of the absolute values of the off-board height change difference values of the adjacent sampling points; Divide the sum of the absolute values of the difference values by the sampling time step to generate the off-board height change rate.

6. The intelligent monitoring system in the production of electronic products according to claim 1, characterized in that: The non-continuous mutation of the off-board height change value refers to that the absolute value of the difference between the off-board height change values of two adjacent sampling points is greater than a specific multiple of the historical fluctuation average.

7. The intelligent monitoring system in the production of an electronic product according to claim 6, characterized in that: The specific method of calculating the heat increase rate is as follows: Identify the time point of the off-board height change value with non-continuous mutation; extracting a heat transfer value sequence of the preset backtracking time length; calculating the temperature increment sum per unit time in the sequence to generate a heat increase rate.

8. The intelligent monitoring system in the production of electronic products according to claim 1, characterized in that: The specific analysis process of the logical interlocking is: real-time monitoring of the activation state of the welding thermal shock alarm signal and the cold welding defect judgment signal; when the signal level of both is in the inactivated state, sending a release pulse signal to the conveyor controller; when the signal level of either is in the activated state, outputting a stop current to the pneumatic brake device.

9. The intelligent monitoring system in the production of an electronic product according to claim 1, wherein: The specific process of generating the floating margin safety interval is: extracting the extreme value of the heat transfer value in the three-dimensional space signal of the qualified product; calculating a preset proportion floating margin extension of the original safety interval width; adding the floating margin extension to the original boundary to generate the floating margin safety interval.

10. The intelligent monitoring system in the production of an electronic product according to claim 9, wherein: The specific way of calculating the preset proportion floating margin extension of the original safety interval width is: obtaining the upper boundary value and the lower boundary value of the preset safety interval; calculating the absolute difference between the upper boundary value and the lower boundary value to generate the original safety interval width; multiplying the original safety interval width by a preset extension coefficient to obtain the floating margin extension.

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