A hot press welding head state recognition method, device and storage medium

Abstract

The application discloses a hot pressure welding head state recognition method and device and a storage medium, wherein the method comprises the following steps: acquiring welding process information of hot pressure welding under different preset experimental conditions in a constant pulse width temperature control mode and a constant temperature control mode; performing feature parameter characterization on the obtained welding process information, acquiring a feature parameter change rule under different preset experimental conditions, and generating a recognition criterion; acquiring welding process information in real time, and extracting feature parameters; and recognizing the hot pressure welding head state according to the extracted feature parameters and the recognition criterion. The application evaluates the welding head state by using dynamic information in the welding process, measures welding current and welding head voltage drop, calculates welding head power input, dynamic resistance and welding energy, and combines hot pressure welding temperature change, so that the hot electric couple temperature sensing sensitivity, the welding head wear condition and the workpiece contact surface heat conduction condition can be recognized; accurate guidance can be provided for process parameter adjustment, welding head grinding and welding head replacement, and the application can be widely applied to the technical field of welding.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a method, apparatus and storage medium for identifying the status of a hot-press welding head. Background Technology

[0002] Hot bar welding (also known as Happa welding) is a welding method that uses the resistance heat of the welding head to conduct heat to the workpiece. The key advantage of this type of equipment is that it controls the temperature of the welding head by adjusting the welding current based on thermocouple temperature measurement to ensure stable heating, thereby controlling the heating of the workpiece. It is widely used in the manufacturing of electronic components and parts.

[0003] The condition of the welding head affects the welding process mainly due to differences in the temperature sensitivity of thermocouples, wear of the welding head, and changes in the surface condition of the working surface.

[0004] In the fabrication of the hot-press welding head, the thermocouple is first melted into a ball and then welded to the temperature-sensing position, such as... Figure 1 As shown, a large molten ball in a thermocouple requires more heat to achieve the same temperature rise; however, the small contact area with the welding head results in less heat being transferred to the thermocouple per unit time. During thermocouple manufacturing, it is difficult to maintain a consistent molten ball size and welding area, leading to differences in the temperature sensitivity of different welding heads. Furthermore, corrosion and fatigue during welding head use can alter the contact area between the thermocouple and the welding head. These differences in thermocouple temperature sensitivity affect temperature control.

[0005] During the use of a welding head, due to continuous contact with the workpiece and cleaning of the welding head surface, the size of the working area of ​​the welding head continuously decreases, a phenomenon defined in the industry as welding head wear. Welding head wear causes differences in the heating process and changes in temperature distribution.

[0006] During the use of the welding head, contamination from flux and other substances, as well as high-temperature oxidation, alter the heat transfer between the welding surface and the workpiece, directly affecting the heating of the weld joint and thus the welding quality.

[0007] In existing equipment applications, changes in the condition of the welding head are controlled by production personnel based on experience, which leads to problems such as untimely and inadequate control, and high personnel costs. With increasing quality requirements and expanding applications of thermocompression welding products, especially in rapid thermocompression welding, differences in thermocouple temperature sensitivity and welding head wear significantly affect temperature control response and temperature distribution uniformity. Changes in the surface condition of the welding head have long been a key factor affecting welding quality, and in actual production, it can only be cleaned periodically based on experience.

[0008] Therefore, accurately and promptly identifying the condition of the welding head is of great significance for production quality management and even for improving welding equipment. To date, there is still no effective method for this. Summary of the Invention

[0009] To at least to some extent solve one of the technical problems existing in the prior art, the purpose of the present invention is to provide a method, device and storage medium for identifying the state of a thermocompression welding head.

[0010] The technical solution adopted by the present invention is as follows:

[0011] A method for identifying the state of a thermocompression welding head includes the following steps:

[0012] Under the constant pulse width temperature rise control mode and the constant temperature control mode, obtain the welding process information of thermocompression welding under different preset experimental conditions;

[0013] Characterize the obtained welding process information, respectively obtain the change rules of characteristic parameters under different preset experimental conditions, and generate identification criteria;

[0014] Obtain the welding process information in real time and extract characteristic parameters;

[0015] Identify the state of the thermocompression welding head according to the extracted characteristic parameters and the identification criteria;

[0016] Among them, the welding process information includes the temperature information, current information and voltage information of the welding head; the identification criteria include the temperature curve, power curve, resistance curve and welding energy under different wear degrees or different heat transfer states of the welding head.

[0017] Further, the temperature information is obtained by the following method:

[0018] Measure the temperature of the welding head through a thermocouple welded on the welding head to obtain temperature information;

[0019] The current information is obtained by the following method:

[0020] Collect the voltage across the shunt and the internal resistance of the shunt, and calculate the loop current based on the collected voltage and internal resistance as the current information;

[0021] The voltage information is obtained by the following method:

[0022] Lead out two wires at the installation end of the welding head to measure the voltage of the welding head to obtain voltage information.

[0023] Further, the method for identifying the state of the thermocompression welding head includes the step of identifying the temperature measurement sensitivity of the welding head, including:

[0024] Set the thermocouple time constant τ;

[0025] When t < 3τ, sample n different temperature points; in the interval of 3τ < t < t1, sample 2n different temperature points; where t1 represents the heating time under ideal heating conditions, such as Figure 3As shown;

[0026] The actual heating curve is obtained by fitting the collected temperature points, and the heating rate k and the final thermocouple time constant τ are solved.

[0027] The larger the final thermocouple time constant τ, the worse the temperature sensitivity of the welding head.

[0028] Furthermore, the expression for the actual temperature rise curve is:

[0029]

[0030] In the formula, T s τ is the actual temperature of the welding head, k is the thermocouple time constant, k is the heating rate, t is the time, and T0 represents the initial temperature of the welding head.

[0031] Furthermore, the wear condition of the welding head is identified through the following methods:

[0032] In the first heating stage, the welding energy required within the preset temperature range is calculated based on the collected current and voltage information.

[0033] The energy difference is calculated based on the obtained welding energy and the preset energy, and the wear of the welding head is calculated based on the energy difference.

[0034] Furthermore, the wear amount ΔM of the welding head shows a significant linear relationship with the energy difference ΔW within the same temperature range before and after the welding head wear during the first heating stage, that is:

[0035] ΔM=k3ΔW+b3

[0036] In the formula, k3 and b3 are both coefficients.

[0037] Furthermore, the heat transfer status of the welding head contact surface is identified through the following methods:

[0038] Based on the current and voltage information, calculate the power trough time t during the second stage of heating up and then transitioning to isothermal equilibrium. g The corresponding power integral value W x ;

[0039] Based on the power integral value W x and the preset reference benchmark W r Calculate the heat transfer coefficient C tg , to represent t g The welding energy deviation rate under the heat transfer condition at that moment;

[0040] Among them, reference benchmark W r The time t represents the power trough value during the second stage of heating and isothermal transition in the adiabatic state. g The corresponding power integral value; Ctg The larger the value, the better the heat transfer between the welding head and the workpiece.

[0041] Furthermore, the expression for the heat transfer coefficient is:

[0042] C tg =W x / W r

[0043] In the formula, W r For reference, W x This is the power integral value calculated under the current heat transfer state of the welding head contact surface.

[0044] Another technical solution adopted in this invention is:

[0045] A thermostatic welding head status identification device, comprising:

[0046] At least one processor;

[0047] At least one memory for storing at least one program;

[0048] When the at least one program is executed by the at least one processor, the at least one processor implements the method described above.

[0049] Another technical solution adopted in this invention is:

[0050] A computer-readable storage medium storing a processor-executable program, which, when executed by a processor, performs the method described above.

[0051] The beneficial effects of this invention are: This invention utilizes dynamic information during the welding process to evaluate the condition of the welding head, measures the welding current and welding head voltage drop, calculates the welding head power input and dynamic resistance, and, combined with the temperature change of thermocompression welding, can effectively identify the thermocouple temperature sensitivity, welding head wear, and workpiece contact surface thermal conductivity; providing accurate guidance for process parameter adjustment, welding head grinding, and welding head replacement. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of the present invention or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the welding head;

[0054] Figure 2This is a schematic diagram of the thermo-pressurization welding process information acquisition system in an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of the ideal and actual temperature rise curves in an embodiment of the present invention;

[0056] Figure 4 These are temperature, resistance, and power diagrams of welding heads with different degrees of wear in embodiments of the present invention;

[0057] Figure 5 These are heat transfer diagrams of the welding head in different embodiments of the present invention;

[0058] Figure 6 This is a schematic diagram of the temperature / power / resistance curves of the welding head under different heat transfer states in an embodiment of the present invention;

[0059] Figure 7 This is a schematic diagram illustrating the selection of characteristic values ​​for the heat transfer state of the welding head in an embodiment of the present invention;

[0060] Figure 8 The heat transfer state and coefficient C in the embodiments of the present invention tg Corresponding diagram;

[0061] Figure 9 This is a flowchart of the steps of a hot-press welding head status identification method in an embodiment of the present invention. Detailed Implementation

[0062] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0063] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0064] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0065] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0066] like Figure 9 As shown, this embodiment provides a method for identifying the status of a thermocompression welding head, including the following steps:

[0067] S1. Under constant pulse width heating control mode and constant temperature control mode, obtain welding process information of hot pressure welding under different preset experimental conditions;

[0068] S2. Characterize the obtained welding process information using feature parameters, obtain the variation law of feature parameters under different preset experimental conditions, and generate identification criteria.

[0069] S3. Acquire welding process information in real time and extract feature parameters;

[0070] S4. Identify the status of the hot-press welding head based on the extracted feature parameters and identification criteria.

[0071] In this embodiment, dynamic information during the welding process is used to assess the condition of the welding head. Welding current and welding head voltage drop are measured, and the welding head power input and dynamic resistance are calculated. Combined with changes in thermocompression welding temperature, this effectively identifies the thermocouple's temperature sensitivity, welding head wear, and the thermal conductivity of the workpiece contact surface. This provides accurate guidance for adjusting process parameters, regrinding the welding head, and replacing the welding head.

[0072] The above method will be explained in detail below with reference to the accompanying drawings and specific embodiments.

[0073] 1. Information Collection Method for Hot Press Welding Process

[0074] In this embodiment, the following can be used: Figure 2 The hot-press welding process information acquisition system shown collects information. The system includes thermocouples, temperature conditioning circuits, welding head voltage conditioning circuits, current conditioning circuits, interface modules, a main control chip, and a host computer. The host computer is connected to the main control chip via a serial port module. The main control module is connected to the temperature conditioning circuit, welding head voltage conditioning circuit, and current conditioning circuit via three ADC conversion interfaces. The temperature conditioning circuit is connected to the thermocouple.

[0075] 1.1 Temperature Acquisition Method

[0076] This invention measures the temperature of the welding head using a thermocouple welded to it, such as... Figure 1 As shown, a high-performance, low-power precision instrumentation amplifier is selected to amplify the thermocouple thermoelectric potential signal, and a low-power, high-precision analog output temperature sensor is used to detect the temperature of the thermocouple reference junction. A cold junction compensation algorithm is invoked in the control program. By writing the relationship between the thermocouple thermoelectric potential and temperature into the control software, the corresponding temperature measurement program is selected when using different thermocouples for temperature measurement. This method can be used for temperature measurement of various thermocouples, including type K, type E, and type J thermocouples, and has strong applicability.

[0077] 1.2 Current Acquisition Method

[0078] The loop current can be calculated by measuring the voltage across the shunt and its fixed internal resistance. The differential signal from the shunt is output as a single-ended signal through a differential amplifier with a high common-mode input voltage range. After passing through a second-order active filter and proportional amplification, it is input to the sampling port of the main control chip. In the sampling program, the sampled value is converted into the actual current value to realize the current measurement.

[0079] 1.3 Voltage Acquisition Method

[0080] To facilitate the measurement of welding head voltage in actual production, two wires are led out from the welding head mounting end to measure the welding head voltage. See [link / details]. Figure 1 Considering the high cost of isolation devices, a high common-mode voltage differential amplifier is also used as the interface device for detection. The differential signal from the solder head mounting end is output as a single-ended signal through the differential amplifier. After second-order active filtering and proportional amplification, it is input to the sampling port of the main control chip. In the sampling program, the sampled value is converted into the actual voltage value to realize voltage measurement.

[0081] 2. Welding head status identification method

[0082] 2.1 Identification of thermocouple temperature sensitivity

[0083] The dynamic differential equation and transfer function for thermocouple temperature measurement are as follows:

[0084]

[0085]

[0086] In equation (1), T sLet \(T_{h}\) be the actual temperature of the welding head, \(\tau\) be the time constant of the thermocouple, and \(T\) be the temperature at the measuring end of the thermocouple spherical head. Therefore, the welding head model is often regarded as an inertial link. During the heating-up stage, the welding head is often heated at a certain heating rate, and the heating-up process of the welding head is approximately represented as a ramp signal. The ideal heating-up curve is:

[0087] \(T(t)=kt + T_{0},t\lt t_{1}\ (3)\)

[0088] In Equation (3), \(k\) is regarded as a constant heating rate; \(t\) is time; \(T_{0}\) represents the initial temperature of the welding head. From Equations (2) and (3), the actual heating-up curve of the welding head can be expressed as:

[0089]

[0090] See Figure 3 , Figure 3 For the schematic diagram of the ideal and actual heating-up curves, during the heating-up stage, from the start of welding to after \(t = 3\tau\) time, the exponential function part of \(e\) in the dynamic response has decayed to 4.98% of the initial value, and the exponential part can be ignored. The difference is \(k\tau\), that is, when \(3\tau\lt t\lt t_{1}\), the slopes of the ideal heating-up curve and the actual heating-up curve are equal, and the steady-state error between the ideal temperature \(T(t)\) and the actual temperature \(T\) s (t) is \(k\tau\).

[0091] It is inevitable that the measuring end of the thermocouple has a certain heat capacity, which causes a lag in the temperature measurement response. In addition, the thermocouple used in thermocompression welding is generally connected to the thermocompression welding head by welding. There is a heat transfer time from the temperature change at the contact surface between the thermocompression welding head and the welded workpiece to the welding position of the thermocouple. In order to simplify the analysis and calculation of the response lag time in the control process, in this embodiment, the time constant of the thermocouple itself and the above-mentioned heat transfer time are combined and referred to as the thermocouple time constant of this thermocompression welding head. For the convenience of expression, it is directly called the "thermocouple time constant".

[0092] The temperature sampling period \(t\) s (\(<1ms\)) of the thermocompression welding power supply in this embodiment is less than the thermocouple time constant (generally in dozens of \(ms\)). Therefore, in the actual heating-up curve, taking the \(3\tau\) moment as the dividing line, when \(t\lt3\tau\), \(n\) different points are sampled ( \(n\) is an integer); in the interval of \(3\tau\lt t\lt t_{1}\), \(2n\) different points are sampled, a total of \(3n\) points. Using the exponential function algorithm in the format of Equation (4) with \(e\) as the base written in advance, the actual heating-up curve is fitted to obtain the values of \(k\) and \(\tau\). Before each welding head is used, a heating-up test program is used, and the power is applied at least \(n_{1}(n_{1}\geq5)\) times repeatedly to obtain \(n_{1}\) groups of different \(k\) and \(\tau\) values. The average of \(n_{1}\) \(k\) and \(\tau\) values is calculated to reduce the accidental error, and the actual heating-up curve and the thermocouple time constant of this welding head are obtained.

[0093] Different temperature sensitivity is defined by dividing the thermocouple into different time constant τ intervals. The larger the τ, the worse the temperature sensitivity of the welding head, and vice versa.

[0094] 2.2 Identification of Welding Head Wear

[0095] The temperature, power, and resistance curves under different wear levels were obtained through experiments, such as... Figure 4 As shown.

[0096] Wear of the solder head reduces the cross-sectional area of ​​its conductive circuit, thus decreasing its volume and heat capacity. The heating process is controlled using a constant pulse width method, with the smaller heat capacity reaching thermal equilibrium first. Therefore, the heating rate accelerates after solder head wear, reducing the energy required to reach the same temperature. To avoid solder melting affecting the calculation of welding energy, the welding energy required within the same temperature range before and after solder head wear in the first heating stage is selected. The wear amount ΔM and the energy reduction ΔW within the same temperature range before and after wear are analyzed and compared. The results show a significant linear relationship between the wear amount ΔM and the energy reduction ΔW within the same temperature range before and after wear in the first heating stage, i.e., ΔM = k3ΔW + b3. That is, after the welding head wears, the welding energy required in the first heating stage decreases. The amount of energy reduction in the same heating range before and after welding head wear is linearly related to the amount of welding head wear. Monitoring the amount of energy reduction in the same heating range in the first heating stage of the welding process can predict the amount of welding head wear. The greater the energy difference in the same temperature range before and after welding head wear, the greater the degree of welding head wear. Therefore, a method is proposed to identify the amount of welding head wear ΔM by the amount of energy reduction ΔW in the same temperature range of the welding process in the first heating stage.

[0097] 2.3 Identification of heat transfer status at the welding head contact surface

[0098] The contact between the welding head and the workpiece includes the contact between the welding head / copper wire and the copper wire / pad. The temperature / power / resistance curves under three heat transfer conditions—adiabatic, under-heat transfer, and normal heat transfer—are analyzed by comparison. (See [reference needed]). Figure 6 We can extract signal features that characterize the heat transfer state of the welding head to monitor and evaluate the welding process.

[0099] See Figure 5 , Figure 5This diagram illustrates heat transfer conditions. The adiabatic heat transfer condition involves energizing the welding head fixed to the chuck, with the welding head not in contact with the workpiece. The under-heat transfer condition occurs when contaminants affect heat transfer between the welding head and the workpiece, or between the workpiece and the pad. This is simulated by using padding paper to alter the heat transfer: Padding at points 1, 3, and 4, or 2, 3, and 4, is referred to as under-heat transfer state A, where only one copper wire is in normal contact with the welding head; padding at point 1 or 2 is state B, where one copper wire is in normal contact with both the welding head and the pad; padding at points 3 and 4 is state C, where two copper wires are in normal contact with the welding head; and padding at point 3 or 4 is state D, where one copper wire is in normal contact with the welding head, and another copper wire is in normal contact with both the welding head and the pad. Normal heat transfer conditions refer to a situation where there are no other contaminants on the contact surface between the welding head and the workpiece.

[0100] Heat is transferred between the welding head and the workpiece through contact heat conduction. The main factors affecting heat transfer between the two objects are temperature difference and contact thermal resistance. The contact thermal resistance between the welding head and the workpiece is difficult to calculate in practical applications; therefore, using contact thermal resistance as a characteristic value to identify the heat transfer state between the welding head and the workpiece is impractical. Since the solder does not melt during the first heating and isothermal stages of thermocompression welding, the welding process information does not change significantly under different heat transfer states. Therefore, the process information during the second heating and isothermal stages is selected for analysis.

[0101] During the second stage of heating, the solder begins to soften or partially melt. Due to the rapid heating, the solder head cannot quickly transfer heat to itself under different heat transfer conditions, resulting in approximately equal peak power values ​​during the heating phase. After the first stage of heating and isothermal control, the solder head temperature is consistent, and the second stage of heating and isothermal control begins at the same point. The second stage of heating uses higher input power, transitioning from heating to isothermal control, and the control mode changes from constant pulse width heating mode to isothermal mode. At this point, the solder head power curve drops rapidly. Simultaneously, to maintain the solder head at the set isothermal temperature, the power curve slowly rises after dropping to a certain value. The heat generation and transfer of the solder head differ under different heat transfer conditions. Subsequently, during the isothermal control phase, the solder head and workpiece gradually reach thermal equilibrium.

[0102] Therefore, the power curves near the transition from heating to isothermal state under different heat transfer conditions, as well as the power curve integral (welding energy), are analyzed as characteristic values ​​for identifying the heat transfer state. Figure 7 This is a schematic diagram showing the power curve of the welding head under adiabatic conditions and the power curves under different heat transfer conditions as a function of time. The trough time t of the power curve is selected. g The integral magnitude of the corresponding power curve indicates the heat transfer between the welding head and the workpiece. Figure 7 As can be seen, as the heat transfer between the welding head and the workpiece improves, the power integral value also increases.

[0103] from Figure 7It can be seen that when the power curve reaches its trough during the transition to the isothermal control stage, the energy input (power integral) already shows a difference. With increasing welding time, the energy increase due to heat transfer at different interfaces varies. The energy difference during the isothermal welding stage is used to characterize heat transfer. The power trough time t during the transition from the second heating stage to the isothermal stage in the adiabatic state is taken as the starting point. g The corresponding power integral value W r Calculate t as a reference. g The difference between the power integral value and Wr under different heat transfer conditions at different times. x (This difference varies under different heat transfer conditions), define the heat transfer coefficient C. tg =W x / W r , to represent t g The welding energy deviation rate under different heat transfer conditions at time t is shown in the following figures. Figure 8 As shown. The horizontal axis 1-6 represent the adiabatic state, under-heat transfer state A, under-heat transfer state B, under-heat transfer state C, under-heat transfer state D, and normal heat transfer state, respectively. Among them, horizontal axis 1 represents state C under the adiabatic state. tg =0. C tg The larger the value, the better the heat transfer between the welding head and the workpiece. This helps to identify differences in heat transfer early in the welding process.

[0104] Because when the solder head has good heat transfer, the solder gradually melts, the contact area between the solder head and the workpiece continuously increases, and the heat transfer between the solder head and the workpiece is enhanced. Different heat transfer states correspond to different degrees of solder melting, W x A higher value indicates better heat transfer between the welding head and the workpiece. Therefore, C is derived. tg The larger the value, the better the heat transfer between the welding head and the workpiece. This is achieved by dividing C... tg By defining the range, different heat transfer states of the welding head can be defined, enabling the identification of the heat transfer state of the welding head and facilitating subsequent control to take appropriate countermeasures.

[0105] Similarly, when heat transfer differs only at certain stages of the process, the change in input energy can also be used to identify the difference.

[0106] In summary, compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0107] (1) This invention derives a mathematical model of the ideal and actual heating curves by analyzing the thermocouple temperature measurement characteristics and the welding head temperature model. It uses the heating program to obtain time and temperature data points, fits the actual heating curve expression based on process information, and thus derives the thermocouple time constant τ to determine the welding head temperature measurement sensitivity. Specifically, by analyzing the expressions of the ideal and actual heating curves of the welding head, it is determined that the welding head temperature model is approximately a first-order inertial element. Based on the characteristics of the actual heating curve, a feature point is defined at time 3τ, and data is collected for a total of 3n (…) before and after the τ time point. Using an integer number of points (n), the actual heating curve is fitted using an exponential function program of the form (4), and the values ​​of k and τ are obtained. The temperature sensitivity is determined based on the thermocouple time constant τ.

[0108] (2) This invention establishes the relationship between the wear amount ΔM of the welding head and the reduction in welding energy ΔW in the same heating range before and after wear. The wear amount of the welding head can be calculated by monitoring the reduction in energy in the same heating range in the first heating stage of the welding process online, so as to realize the online identification of the wear amount of the welding head.

[0109] (3) The present invention uses the power trough value t during the second stage of heating and constant temperature transition in the adiabatic state as the time of the power trough value. g The corresponding power integral value W r Calculate t as a reference. g The difference between the power integral value and Wr under different heat transfer conditions at different times. x (W under different heat transfer conditions) x (Different), define the heat transfer coefficient C tg =W x / W r , to represent t g The welding energy deviation rate under different heat transfer conditions at time C tg The larger the diameter, the better the heat transfer between the welding head and the workpiece.

[0110] This embodiment also provides a thermocompression welding head status identification device, including:

[0111] At least one processor;

[0112] At least one memory for storing at least one program;

[0113] When the at least one program is executed by the at least one processor, the at least one processor implements Figure 9 The method shown.

[0114] This embodiment of the thermocompression welding head status identification device can execute the thermocompression welding head status identification method provided in the method embodiment of the present invention, and can execute any combination of the implementation steps of the method embodiment, and has the corresponding functions and beneficial effects of the method.

[0115] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform... Figure 9 The method shown.

[0116] This embodiment also provides a storage medium storing instructions or programs that can execute the hot-press welding head status identification method provided in the method embodiment of the present invention. When the instructions or programs are run, any combination of implementation steps of the method embodiment can be executed, and the method has the corresponding functions and beneficial effects.

[0117] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.

[0118] Furthermore, although the invention has been described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the described functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the invention. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional skill of an engineer. Therefore, those skilled in the art can implement the invention as set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of the invention, which is determined by the full scope of the appended claims and their equivalents.

[0119] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion 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 a computer 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 invention. 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.

[0120] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0121] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0122] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0123] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0124] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0125] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for identifying the status of a hot-press welding head, characterized in that, Includes the following steps: Under constant pulse width heating control mode and constant temperature control mode, welding process information of hot pressure welding under different preset experimental conditions is obtained; The obtained welding process information is characterized by feature parameters, and the variation law of feature parameters under different preset experimental conditions is obtained to generate identification criteria. Real-time acquisition of welding process information and extraction of feature parameters; The condition of the hot-press welding head is identified based on the extracted feature parameters and identification criteria; The welding process information includes the temperature, current, and voltage information of the welding head; the identification criteria include the temperature curve, power curve, resistance curve, and welding energy of the welding head under different wear levels or different heat transfer states. The hot-press welding head status identification method includes the step of identifying the temperature sensitivity of the welding head, including: Set the thermocouple time constant ; exist t < At that time, sampling n At different temperature points; < t < t 1 interval, sample 2 n There are several different temperature points; among them t 1 represents the heating time under ideal heating conditions; The actual heating curve is obtained by fitting the collected temperature points, and the heating rate is solved. k and the final thermocouple time constant ; Among them, the final thermocouple time constant The larger the value, the worse the temperature sensitivity of the welding head.

2. The method for identifying the status of a hot-press welding head according to claim 1, characterized in that, The temperature information was obtained through the following methods: Temperature information is obtained by measuring the temperature of the welding head using a thermocouple welded to it. The current information is acquired through the following methods: By collecting the voltage across the shunt and the internal resistance of the shunt, the loop current is calculated based on the collected voltage and internal resistance, and this information is used as current information. The voltage information is acquired through the following methods: Two wires are led out from the welding head mounting end to measure the welding head voltage and obtain voltage information.

3. The method for identifying the status of a hot-press welding head according to claim 1, characterized in that, in actual The expression for the heating curve is: In the formula, T s This refers to the actual temperature of the welding head. Thermocouple time constant k For the heating rate, t For time, T 0 indicates the initial temperature of the welding head.

4. The method for identifying the status of a hot-press welding head according to claim 1, characterized in that, The wear condition of the welding head can be identified using the following methods: In the first heating stage, the welding energy required within the preset temperature range is calculated based on the collected current and voltage information. The energy difference is calculated based on the obtained welding energy and the preset energy, and the wear of the welding head is calculated based on the energy difference.

5. The method for identifying the status of a hot-press welding head according to claim 4, characterized in that, Welding head wear Δ M The energy difference Δ between the welding head and the same temperature range before and after wear during the first heating stage. W It exhibits a significant linear relationship, that is: D M = k 3D W + b 3 In the formula, k 3. b 3 are all coefficients.

6. The method for identifying the status of a hot-press welding head according to claim 1, characterized in that, The heat transfer status of the welding head contact surface is identified using the following methods: Based on the current and voltage information, calculate the power trough times during the second stage of heating up and then transitioning to isothermal equilibrium. t g Corresponding power integral value W x ; Based on power integral value W x and preset reference benchmark W r Calculate the heat transfer coefficient C tg , to indicate t g The welding energy deviation rate under the heat transfer condition at that moment; Among them, reference benchmark W r The time of the power trough during the second stage of heating and isothermal transition in the adiabatic state. t g The corresponding power integral value; C tg The larger the value, the better the heat transfer between the welding head and the workpiece.

7. The method for identifying the status of a hot-press welding head according to claim 6, characterized in that, The expression for the heat transfer coefficient is: C tg = W x / W r In the formula, W r For reference, W x This is the power integral value calculated under the current heat transfer state of the welding head contact surface.

8. A thermoforming welding head status identification device, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method of any one of claims 1-7.

9. A computer-readable storage medium storing a processor-executable program, characterized in that, The processor-executable program, when executed by the processor, is used to perform the method as described in any one of claims 1-7.

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