Temperature monitoring method, device and storage medium for reflow soldering

Abstract

The present application belongs to the field of temperature monitoring technology, and specifically relates to a temperature monitoring method, device and storage medium for reflow soldering based on a sine function. The method includes: obtaining historical temperature data of reflow soldering; correcting a preset sine function based on the historical temperature data to obtain a temperature monitoring model; constructing a HotellingT2 control chart based on the temperature monitoring model; and monitoring the temperature of reflow soldering through the HotellingT2 control chart. The problem of inaccurate temperature monitoring of reflow soldering can be solved. By fitting the historical temperature data, the function parameters of the preset sine function are obtained, thereby obtaining a temperature monitoring model, and then constructing a HotellingT2 control chart based on the temperature monitoring model, and monitoring the temperature of reflow soldering through the HotellingT2 control chart. In this way, there is no need to set the temperature range of each area, and the temperature information at the current moment in the reflow soldering process can be obtained in real time, and compared with the temperature corresponding to the HotellingT2 control chart at the current moment, which can improve the accuracy of temperature monitoring of reflow soldering.

Description

Technical Field

[0001] The present application belongs to the field of temperature monitoring technology, and specifically relates to a temperature monitoring method, device and storage medium for reflow soldering. Background Art

[0002] Reflow soldering technology is an important part of surface mount soldering technology. The data of reflow soldering is mainly a set of complex data of time and temperature. The corresponding temperature curve includes four areas: preheating, constant temperature, reflow soldering and cooling. If the temperature in any area is too high or too low, it may cause problems with the soldering quality. Therefore, it is necessary to monitor the temperature during the reflow soldering process.

[0003] The conventional temperature monitoring method for reflow soldering includes: setting the temperature range of each area respectively, and outputting a prompt message when the current temperature is higher than the temperature range of the current area.

[0004] However, during the reflow soldering process, the temperature in each area changes in real time. If the temperature is monitored according to the temperature range of each area, the actual temperature at a certain moment may be higher than the required temperature at the current moment, but still within the temperature range of the current area, resulting in inaccurate temperature monitoring of the reflow soldering. Summary of the invention

[0005] The present application provides a temperature monitoring method, device and storage medium for reflow soldering, which can solve the problem of inaccurate temperature monitoring for reflow soldering. The present application provides the following technical solutions:

[0006] In a first aspect, a temperature monitoring method for reflow soldering is provided, the method comprising:

[0007] Get historical temperature data of reflow soldering;

[0008] Modify the preset sinusoidal function based on the historical temperature data to obtain a temperature monitoring model;

[0009] Constructing a HotellingT2 control chart based on the temperature monitoring model;

[0010] The temperature of the reflow soldering is monitored by the HotellingT2 control chart.

[0011] Optionally, the historical temperature data includes n pieces of data; the preset sinusoidal function is a nonlinear sinusoidal function, and the preset sinusoidal function is:

[0012]

[0013] Among them, i is used to represent the i-th sine function; j is used to represent the j-th data, and j is a positive integer less than n; x is used to represent temperature data; a is used to represent the amplitude of the preset sine function; b is used to represent the frequency of the sine function; ε is the error term; c is the constant term; s is used to represent the total number of times.

[0014] Optionally, i is an integer greater than or equal to 1 and less than or equal to 8.

[0015] Optionally, the value of s is 2.

[0016] Optionally, the step of correcting a preset sinusoidal function based on the historical temperature data to obtain a temperature monitoring model includes:

[0017] Fitting the historical temperature data to obtain a fitting result;

[0018] Determine function parameters of the preset sine function based on the fitting result;

[0019] The function parameters are input into the preset sine function to obtain the temperature monitoring model.

[0020] Optionally, the function parameters include at least one group of function parameters, and before inputting the function parameters into the preset sinusoidal function to obtain the temperature monitoring model, the method further includes:

[0021] The at least one set of function parameters is verified, and function parameters used to input the preset sine function are determined from the at least one set of function parameters.

[0022] Optionally, monitoring the temperature of the reflow soldering by using the HotellingT2 control chart includes:

[0023] During the temperature monitoring process of reflow soldering, obtain real-time temperature information;

[0024] When the temperature indicated by the temperature data is greater than or lower than the temperature corresponding to the HotellingT2 control diagram at the current moment, a prompt message is output.

[0025] In a second aspect, an electronic device is provided, the device comprising a processor and a memory; a program is stored in the memory, and the program is loaded and executed by the processor to implement the temperature monitoring method for reflow soldering described in the first aspect.

[0026] In a third aspect, a computer-readable storage medium is provided, wherein a program is stored in the storage medium, and when the program is executed by a processor, the program is used to implement the temperature monitoring method for reflow soldering provided in the first aspect.

[0027] The beneficial effects of the present application are: obtaining historical temperature data of reflow soldering; correcting a preset sinusoidal function based on the historical temperature data to obtain a temperature monitoring model; constructing a HotellingT2 control chart based on the temperature monitoring model; and monitoring the temperature of reflow soldering through the HotellingT2 control chart. The problem of inaccurate temperature monitoring of reflow soldering can be solved. By fitting the historical temperature data, the function parameters of the preset sinusoidal function are obtained, thereby obtaining a temperature monitoring model, and then constructing a HotellingT2 control chart based on the temperature monitoring model, and monitoring the temperature of reflow soldering through the HotellingT2 control chart. In this way, there is no need to set the temperature range of each area, and the temperature information at the current moment in the reflow soldering process can be obtained in real time, and compared with the temperature corresponding to the HotellingT2 control chart at the current moment, which can improve the accuracy of temperature monitoring of reflow soldering. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 This is a temperature schematic diagram of a reflow soldering process provided by an embodiment of the present application;

[0030] Figure 2 is a flow chart of a temperature monitoring method for reflow soldering provided by an embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of abnormal temperature during reflow soldering provided by an embodiment of the present application;

[0032] Figure 4 This is a temperature schematic diagram of a reflow soldering process provided by an embodiment of the present application;

[0033] Figure 5 It is a schematic diagram of a control diagram provided by an embodiment of the present application;

[0034] Figure 6 It is a schematic diagram of a control diagram provided by an embodiment of the present application;

[0035] Figure 7 This is a schematic diagram of a control diagram of a method without a matrix provided by an embodiment of the present application;

[0036] Figure 8 is a block diagram of a temperature monitoring device for reflow soldering provided by an embodiment of the present application;

[0037] Fig. 9 It is a block diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0038] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0039] B-2022CN348-I

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0041] In the present application, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present application.

[0042] The following is an introduction to the terms used in this application.

[0043] Reflow soldering technology: It is an important part of surface mount technology (SMT, Surface Mount Technology). The data of reflow soldering is mainly a set of complex data of time and temperature. The temperature curve of reflow soldering (Reflow Profile) includes four major areas: preheating (Pre-heat), constant temperature (Soak), reflow (Reflow), and cooling (Cooling). Therefore, the reflow soldering data is not a linear data, but a nonlinear curve data.

[0044] Temperature curve control mainly consists of temperature changes in four areas:

[0045] 1. Preheating zone: usually from room temperature to 150°C, the temperature rise rate in this zone should be 1-2°C per second.

[0046] 2. Constant temperature zone: The temperature is usually controlled at 180°C. The constant temperature zone usually takes up 90 to 120 seconds of the entire temperature curve.

[0047] 3. Reflow area: This is the highest temperature area. Different peak temperatures will be set according to the components on different circuit boards, usually 230-250°C.

[0048] 4. Cooling zone: The temperature will drop from 240℃ to about 45℃. If the cooling process is too long or too short, it will cause welding quality problems. The general cooling rate is 3 to 10℃ per second.

[0049] Plot the above temperature specifications into a graph, refer to Figure 1 Too high or too low temperature in any area may cause problems with soldering quality. Since the electronic components contained in the circuit board of each product may be different, the peak temperature and the lowest high-temperature resistant components of each product may be different. Therefore, the temperature curve drawn for each product will be different. The temperature curve allows the operator to make appropriate changes to optimize the reflow process.

[0050] B-2022CN348-I

[0051] The temperature monitoring method for reflow soldering provided by the present application is described in detail below.

[0052] like Figure 1 As shown, the embodiment of the present application provides a temperature monitoring method for reflow soldering. The implementation of the method can rely on a computer program. The computer program can be run on a computer device such as a smart phone, a tablet computer, a personal computer, or a server. This embodiment does not limit the operating subject of the method. The method includes at least the following steps:

[0053] Step 101, obtaining historical temperature data of reflow soldering.

[0054] In this embodiment, the historical temperature data includes n pieces of historical temperature data collected during the reflow soldering process.

[0055] Here, n is an integer greater than 0, for example, the value of n includes 12 or 16.

[0056] In actual implementation, the value of n may also be other positive integers, and this embodiment does not limit the value of n.

[0057] Step 102: Correct the preset sine function based on the historical temperature data to obtain a temperature monitoring model.

[0058] The preset sine function is a nonlinear sine function.

[0059] Specifically, the preset sine function is:

[0060]

[0061] In the formula, i is used to represent the i-th sine function; j is used to represent the j-th data, and j is a positive integer less than n; x is used to represent temperature data; a is used to represent the amplitude of the preset sine function; b is used to represent the frequency of the sine function; ε is the error term; c is the constant term; s is used to represent the total number of times.

[0062] Optionally, i is an integer greater than or equal to 1 and less than or equal to 8.

[0063] Since the historical temperature data in the reflow soldering process is not a linear data but a nonlinear curve data, based on this, in this embodiment, a temperature monitoring model is constructed by a nonlinear preset sine function. The temperature monitoring model is a mathematical model.

[0064] Specifically, a preset sine function is corrected based on historical temperature data to obtain a temperature monitoring model, including: fitting the historical temperature data to obtain a fitting result; determining function parameters of the preset sine function based on the fitting result; and inputting the function parameters into the preset sine function to obtain the temperature monitoring model.

[0065] Optionally, after fitting the historical temperature data and obtaining the fitting result, the function parameters can be obtained by a preset parameter estimation algorithm.

[0066] Among them, the preset parameter estimation algorithm is non-linear least squares (NLS).

[0067] In addition, in this embodiment, since the historical temperature data includes n data, the estimated function parameters include at least one set of function parameters. Each set of function parameters obtained needs to be verified to determine the function parameters with the best effect in at least one set of function parameters and input them into the preset sine function.

[0068] Specifically, before inputting the function parameters into the preset sinusoidal function to obtain the temperature monitoring model, the method further includes: verifying at least one group of function parameters, and determining the function parameters used to input the preset sinusoidal function from the at least one group of function parameters.

[0069] Optionally, verifying at least one set of function parameters includes: verifying at least one set of function parameters using a preset verification algorithm.

[0070] The preset verification algorithm is the Schwarz Information Criterion (SIC).

[0071] For example, after verification by the preset verification algorithm, the sine function summed twice performs best. At this time, the sine function can be expressed by the following formula:

[0072] f(xi，j , β i )=a 1i sin(b 1i x ij )+a 2i sin(b 2i x ij +c 2i )+ε ij

[0073] In the formula, i is used to represent the i-th sine function; j is used to represent the j-th data; x is used to represent temperature data; a is used to represent the amplitude of the preset sine function; b is used to represent the frequency of the sine function; ε is the error term; and c is the constant term.

[0074] Step 103: construct a HotellingT2 control chart based on the temperature monitoring model.

[0075] Step 104, monitoring the temperature of the reflow soldering through the HotellingT2 control chart.

[0076] After multiple reflow processes, several temperature-time data can be obtained. Based on these temperature-time data, temperature specification curves for the four areas of preheating, constant temperature, reflow and cooling can be set, and the temperature during the reflow process can be monitored through the temperature specification curve.

[0077] For example: Reference Figure 2 It can be seen that when one data is in the cooling zone, the temperature is higher than other data at the same time point, which may cause the welded electronic components to shift, resulting in problems with the welding quality and ultimately causing the product to be scrapped.

[0078] In a traditional reflow temperature monitoring method, refer to Figure 3 , a hierarchical approach is set up in each area to monitor the temperature. However, when the temperature deviates, there is a possibility that the abnormality cannot be effectively monitored.

[0079] refer to Figure 2 The abnormal value in the cooling zone is Figure 2 The abnormal value is obviously different from other data and higher than the temperature standard curve, but it does not exceed Figure 3 The monitoring temperature range of the cooling zone is therefore not able to be monitored.

[0080] In order to solve the above problems, in this embodiment, by fitting the historical temperature data, the function parameters of the preset sinusoidal function are obtained, thereby obtaining the temperature monitoring model, and then the HotellingT2 control chart is constructed based on the temperature monitoring model, and the temperature of the reflow soldering is monitored by the HotellingT2 control chart. In this way, there is no need to set the temperature range of each area, and the temperature information at the current moment in the reflow soldering process can be obtained in real time, and compared with the temperature corresponding to the HotellingT2 control chart at the current moment. When the temperature indicated by the temperature information at the current moment is greater than or lower than the temperature corresponding to the control chart at the current moment, a prompt message is output to prompt the user that the temperature is abnormal.

[0081] Specifically, the temperature of the reflow soldering is monitored through the HotellingT2 control chart, including: obtaining real-time temperature information during the temperature monitoring process of the reflow soldering; and outputting a prompt message when the temperature indicated by the temperature data is greater than or lower than the temperature corresponding to the HotellingT2 control chart at the current moment.

[0082] In another traditional reflow temperature monitoring method, that is, the polynomial regression method, when the temperature curve is too complex, it will cause overfitting, which will eventually lead to inaccurate monitoring during the temperature monitoring process. Polynomial regression usually has the problem of too many estimated parameters and poor model fit. At the same time, in order to smooth the intersection, the polynomial regression method divides the curve into multiple segments, resulting in too many parameters, resulting in a decrease in calculation speed and requiring a large number of samples for estimation.

[0083] refer to Figure 5 and Figure 6 , Figure 5 The control chart corresponding to the modified sine function is, Figure 6 is the control chart corresponding to the polynomial regression method, Figure 5 and Figure 6 Included Figure 2 The abnormal value indicated by the cooling zone is Figure 5 and Figure 6 However, in the control chart corresponding to the polynomial regression method, the control line is closer to the normal data, which increases the probability of misjudgment. In the control chart corresponding to the modified sine function, the abnormal value and the normal value can be clearly distinguished, thus reducing the possibility of misjudgment.

[0084] In another method, the traditional reflow temperature monitoring method, i.e., the non-matrix method, the deviation degree between each temperature curve and the baseline is found through the baseline. The deviation degree can be measured by some distance measurement methods, such as the maximum deviation method, the sum of square deviations, and the sum of absolute deviations. The distance measured by these methods is used to determine whether the data is an abnormal value as a basis for issuing a warning. However, the non-matrix method has low sensitivity and cannot effectively monitor abnormalities in real time when abnormalities occur.

[0085] In one example, in order to compare the performance of the reflow soldering temperature monitoring method, the polynomial regression method and the non-matrix method provided in this embodiment, the three methods are compared in ARLout by means of control charts with the same ARLin=200 as the benchmark when the temperature data is abnormal.

[0086] Among them, ARLin is in control Average Run Length, which means the average frequency of the control chart issuing an alarm when the monitored temperature data is normal. That is, when the monitored temperature is in a normal state, the larger the value of ARLin, the better. It means that the probability of false alarms in the control chart is lower.

[0087] On the contrary, ARLout is when the monitored temperature is abnormal, and we hope to detect the abnormality as soon as possible. Therefore, the smaller the ARLout value, the better.

[0088] This comparison method shifts one parameter at a time, and the degree of shift is m times the standard deviation of the parameter plus the average value of the parameter, where m ranges from 0.5 to 3.

[0089] From the equation:

[0090]

[0091] To generate abnormal temperature data.

[0092] in, The average values ​​of the 16 function parameters generated for the 16 sets of historical temperature data are taken. The average values ​​and standard deviations of the parameters are shown in Table 1:

[0093] Table 1:

[0094]

[0095]

[0096] εij The error term is a normally distributed variable with a mean of 0 and a standard deviation of 1. This equation is used to generate simulated temperature data for the control chart to monitor. When an alarm is issued, data generation stops and the number of times the alarm is issued is recorded. The average value taken after 200 iterations will be the result of the ARLout method. The simulated temperature data is generated by this parameter offset method to compare the performance of the three ARLout methods.

[0097] The non-matrix method is a mixed indicator that uses the average curve of 16 sets of historical temperature data as the baseline and the maximum deviation:

[0098]

[0099] The sum of the squared deviations is:

[0100]

[0101] Total absolute deviation:

[0102]

[0103] In the formula, i is the i-th group of data, is the i-th group of curves, As the baseline, as a method to measure the distance between the curve and the baseline, each method will get 16 points, and the respective control charts are:

[0104]

[0105] is the standard deviation of each method, is 3, It is the average of 16 data points of each method. Figure 7 The ARLout of the non-matrix method is the value of the ARLout of the maximum deviation method, the sum of squared deviations, and the sum of absolute deviations when the out-of-control signal occurs earliest in their respective control charts. Using the three charts together is expected to enhance their sensitivity in detecting abnormalities.

[0106] The comparison results are shown in Table 3, Table 4, Table 5, Table 6, and Table 7:

[0107] Table 3:

[0108]

[0109]

[0110] Table 4:

[0111]

[0112] Table 5:

[0113]

[0114] Table 6:

[0115]

[0116]

[0117] Table 7:

[0118]

[0119] Based on the results in Table 3, Table 4, Table 5, Table 6, and Table 7, it can be seen that when the reflow temperature curve of this embodiment is offset or abnormal, the performance of ARLout is generally smaller than that of the other two methods, and when m is greater than or equal to 2, the performance of ARLout is quite close to 1. The parameters a1 and a2 in the table are the amplitude of the curve, the parameters b1 and b2 are the frequency of the curve, and the parameter c1 is the horizontal phase constant of the curve.

[0120] The temperature monitoring method for reflow soldering provided in this embodiment can correctly characterize the reflow soldering technical data, and the parameters are interpretable and provide competitive monitoring performance. Compared with previous polynomials, the present invention provides better fitting results. When the temperature is abnormal, it has better monitoring capabilities than polynomials and non-matrix.

[0121] In summary, the temperature monitoring method of reflow soldering provided in this embodiment obtains historical temperature data of reflow soldering; corrects the preset sinusoidal function based on the historical temperature data to obtain a temperature monitoring model; constructs a HotellingT2 control chart based on the temperature monitoring model; and monitors the temperature of reflow soldering through the HotellingT2 control chart. The problem of inaccurate temperature monitoring of reflow soldering can be solved. By fitting the historical temperature data, the function parameters of the preset sinusoidal function are obtained, thereby obtaining a temperature monitoring model, and then constructing a HotellingT2 control chart based on the temperature monitoring model, and monitoring the temperature of reflow soldering through the HotellingT2 control chart. In this way, there is no need to set the temperature range of each area, and the temperature information at the current moment in the reflow soldering process can be obtained in real time, and compared with the temperature corresponding to the HotellingT2 control chart at the current moment, the accuracy of temperature monitoring of reflow soldering can be improved.

[0122] Figure 8 It is a block diagram of a temperature monitoring device for reflow soldering based on a sine function provided in an embodiment of the present application. The device includes at least the following modules: a data acquisition module 810, a function correction module 820, a control chart construction module 830 and a temperature monitoring module 840.

[0123] The data acquisition module 810 is used to acquire historical temperature data of reflow soldering;

[0124] A function correction module 820, used to correct a preset sine function based on historical temperature data to obtain a temperature monitoring model;

[0125] A control chart construction module 830 is used to construct a HotellingT2 control chart based on a temperature monitoring model;

[0126] The temperature monitoring module 840 is used to monitor the temperature of the reflow soldering through the HotellingT2 control chart.

[0127] For relevant details, refer to the above embodiments.

[0128] It should be noted that: the temperature monitoring device for reflow soldering provided in the above embodiment only uses the division of the above functional modules as an example when performing temperature monitoring of reflow soldering. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the temperature monitoring device for reflow soldering is divided into different functional modules to complete all or part of the functions described above. In addition, the temperature monitoring device for reflow soldering provided in the above embodiment and the temperature monitoring method embodiment for reflow soldering belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0129] This embodiment provides an electronic device, such as Fig. 9 As shown, the electronic device can be Figure 1 The electronic device at least includes a processor 901 and a memory 902.

[0130] The processor 901 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 901 may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor 901 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 901 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 901 may also include an AI (Artificial Intelligence) processor, which is used to process computing operations related to machine learning.

[0131] The memory 902 may include one or more computer-readable storage media, which may be non-transitory. The memory 902 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 902 is used to store at least one instruction, which is used to be executed by the processor 901 to implement the temperature monitoring method of reflow soldering provided in the method embodiment of the present application.

[0132] In some embodiments, the electronic device may further optionally include: a peripheral device interface and at least one peripheral device. The processor 901, the memory 902 and the peripheral device interface may be connected via a bus or a signal line. Each peripheral device may be connected to the peripheral device interface via a bus, a signal line or a circuit board. Schematically, the peripheral devices include but are not limited to: a radio frequency circuit, a touch display screen, an audio circuit, and a power supply.

[0133] Of course, the electronic device may also include fewer or more components, which is not limited in this embodiment.

[0134] Optionally, the present application also provides a computer-readable storage medium, in which a program is stored, and the program is loaded and executed by a processor to implement the push record cleaning method of the above method embodiment.

[0135] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A temperature monitoring method for reflow soldering, characterized in that: The method comprises: Get historical temperature data of reflow soldering; Modify the preset sinusoidal function based on the historical temperature data to obtain a temperature monitoring model; Constructing a HotellingT2 control chart based on the temperature monitoring model; The temperature of the reflow soldering is monitored by the HotellingT2 control chart; The historical temperature data includes n data; the preset sine function is a nonlinear sine function, and the preset sine function is: Among them, i is used to represent the i-th sine function; j is used to represent the j-th data, and j is a positive integer less than n; x is used to represent temperature data; a is used to represent the amplitude of the preset sine function; b is used to represent the frequency of the sine function; ε is the error term; c is the constant term; s is used to represent the total number of times.

2. The method according to claim 1, characterized in that The i is an integer greater than 1 and less than or equal to 8.

3. The method according to claim 1, characterized in that The value of s is 2.

4. The method according to claim 1, characterized in that The method of correcting a preset sinusoidal function based on the historical temperature data to obtain a temperature monitoring model includes: Fitting the historical temperature data to obtain a fitting result; Determine function parameters of the preset sine function based on the fitting result; The function parameters are input into the preset sine function to obtain the temperature monitoring model.

5. The method according to claim 4, characterized in that The function parameters include at least one group of function parameters. Before the function parameters are input into the preset sine function to obtain the temperature monitoring model, the following further includes: The at least one set of function parameters is verified, and function parameters used to input the preset sine function are determined from the at least one set of function parameters.

6. The method according to claim 1, characterized in that The temperature of the reflow soldering is monitored by the HotellingT2 control diagram, including: During the temperature monitoring process of reflow soldering, obtain real-time temperature information; When the temperature indicated by the temperature data is greater than or lower than the temperature corresponding to the HotellingT2 control diagram at the current moment, a prompt message is output.

7. An electronic device, characterized in that: The electronic device comprises: a processor and a memory; a program is stored in the memory, and the program is loaded and executed by the processor to implement the temperature monitoring method for reflow soldering as claimed in any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that: The storage medium stores a program, and when the program is executed by the processor, it is used to implement the temperature monitoring method for reflow soldering as described in any one of claims 1 to 6.

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