Method for controlling ultrasonic bonding process

Abstract

A method for controlling an ultrasonic bonding process, comprising the following steps: S1, when welding is started, an ultrasonic system operates, reaches and maintains a set welding voltage, such that the ultrasonic system forms resonance; S2, under a preset ultrasonic excitation voltage, a pre-welding stage is carried out; S3, a power profile model is established, and operating parameters of the ultrasonic system in the welding process are collected; S4, it is determined whether the operating parameters meet expected welding, and if yes, go to step S5, or if no, go to step S6; S5, a normal welding process is executed, and a final welding stage is carried out; S6, a welding process using preset welding parameters is executed, and a final welding stage is carried out. According to the present invention, quality control in the ultrasonic welding process directly cooperates with a controller of an ultrasonic generator, thus increasing the response speed, and facilitating the guarantee of welding quality.

Description

Ultrasonic bonding process control method Technical Field

[0001] The present invention relates to the field of welding technology, and in particular to an ultrasonic bonding process control method. Background Art

[0002] In the field of welding technology, the ordinary welding process is open-loop. Usually, after the welding is completed, it is necessary to determine whether the welding is reliable by evaluating the current, voltage, and deformation of the welded material in the ultrasonic transducer during the welding process.

[0003] FIG1 is a schematic diagram of a conventional welding method.

[0004] As shown in Figure 1, the traditional welding method is to perform welding by presetting welding parameters. Finally, the welding process data is collected to judge the quality of the welding.

[0005] This method can only tell you the result after welding, but cannot tell you the quality problems during the welding process.

[0006] In view of this, the inventors of the present application have designed an ultrasonic bonding process control method in order to overcome the above technical problems.

[0007] Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the prior art welding method that the quality can only be judged after the end and quality problems cannot be known during the process, and to provide an ultrasonic bonding process control method.

[0009] The present invention solves the above technical problems through the following technical solutions:

[0010] An ultrasonic bonding process control method is characterized in that the ultrasonic bonding process control method comprises the following steps:

[0011] S1. When welding starts, the ultrasonic system works to reach and maintain the set welding voltage, so that the ultrasonic system forms resonance;

[0012] S2. Performing a pre-welding stage under a preset ultrasonic excitation voltage;

[0013] S3. Establish a power profile model and collect the working parameters of the ultrasonic system during welding;

[0014] S4, determine whether the working parameters meet the expected welding; if so, proceed to step S s ; If not, proceed to step S6;

[0015] S5. Execute the normal welding process and proceed to the final welding stage;

[0016] S6. Execute the welding process with preset welding parameters and proceed to the final welding stage.

[0017] According to one embodiment of the present invention, step S1 includes the following steps:

[0018] S 11 , User preset welding parameters: Before the ultrasonic intelligent control system is turned on, a welding test is performed as a sample for machine learning;

[0019] S 12 , the machine starts oscillating using preset welding parameters.

[0020] According to one embodiment of the present invention, the welding parameters include current, welding force and welding time during the welding process.

[0021] According to one embodiment of the present invention, the welding parameters further include current, voltage, welding force, peak power in the pre-welding stage and the final welding stage, and electrical energy during the welding process.

[0022] According to one embodiment of the present invention, establishing the power profile model in step S3 includes:

[0023] S 31 , take the excitation voltage and welding force in the basic welding process parameters as input, and power as output. In the constant voltage source system, the transducer vibration speed remains unchanged, and the output power is:;

[0024] Where W is the output power, V is the excitation voltage, and Rm is the transducer impedance;

[0025] S 32 , the transducer load impedance and pressure satisfy: f(p) = F(Rm), f(V,F) = F(P);

[0026] Where f(p) is power, F(Rm) is impedance, f(V,F) is the excitation voltage and welding force, and F(P) is welding power.

[0027] S 33 , fit the power changes during the welding process to obtain the welding process power profile model.

[0028] According to an embodiment of the present invention, step S4 includes: establishing power state detection points under the time axis, with the end point of time being a key detection point.

[0029] According to one embodiment of the present invention, step S4 includes: when during the welding process, the key detection point falls within the power contour model, and the remaining at least two power state detection points fall within the power contour model, it is determined that the welding meets the expected requirements.

[0030] According to an embodiment of the present invention, the step S4 includes: when, during the welding process, the key detection point and more than one power state detection point do not fall within the power profile model, determining that the welding does not meet the expected requirements.

[0031] According to one embodiment of the present invention, in the final welding stage, the welding end point is controlled according to the ultrasonic energy or welding type variables in the final welding stage before the intelligent control system is turned on.

[0032] According to an embodiment of the present invention, the power state detection point is one or more detection points.

[0033] The positive progress effect of the present invention is:

[0034] The ultrasonic bonding process control method of the present invention has the following advantages:

[0035] 1. The quality control of the ultrasonic welding process is directly coordinated with the control controller of the ultrasonic generator, thereby improving the response speed;

[0036] 2. It is conducive to ensuring welding quality.

[0037] Summary of the Figures

[0038] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which like reference numerals represent like features throughout, wherein:

[0039] FIG1 is a schematic diagram of a conventional welding method.

[0040] FIG2 is a flow chart of the ultrasonic bonding process control method of the present invention.

[0041] FIG3 is a schematic diagram of a welding power curve in the ultrasonic bonding process control method of the present invention.

[0042] FIG4 is a schematic diagram of decomposition welding in the ultrasonic bonding process control method of the present invention.

[0043] Preferred embodiments of the present invention

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0045] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.

[0046] Furthermore, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the present specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description herein.

[0047] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings lying behind each term.

[0048] Figure 2 is a flow chart of the ultrasonic bonding process control method of the present invention. Figure 3 is a schematic diagram of the welding power curve in the ultrasonic bonding process control method of the present invention. Figure 4 is a schematic diagram of the decomposition welding in the ultrasonic bonding process control method of the present invention.

[0049] As shown in FIG2 to FIG4, the present invention discloses an ultrasonic bonding process control method, which includes the following steps:

[0050] Step S1: When welding starts, the ultrasonic system works to reach and maintain the set welding voltage so that the ultrasonic system forms resonance.

[0051] Before the ultrasonic intelligent control system is turned on, the user conducts a welding test based on experience as a sample for machine learning. The machine uses preset welding parameters for oscillation, pre-welding stage, and final welding stage, and the process uses time as the end control point.

[0052] Preferably, step S1 includes the following steps:

[0053] Step S 11 , User preset welding parameters: Before the ultrasonic intelligent control system is turned on, a welding test is performed as a sample for machine learning;

[0054] Step S 12 , the machine starts oscillating using preset welding parameters.

[0055] Preferably, the welding parameters include current, welding force, welding time, etc. during the welding process, which are not limited here and can also be other welding parameters, all of which are applicable to this method.

[0056] Further preferably, based on the ultrasonic system and based on key welding process parameters, the welding parameters also include current, voltage, welding force, peak power in the pre-welding stage and final welding stage, and electrical energy during the welding process, the welding parameters are monitored.

[0057] Step S2: performing a pre-welding stage under a preset ultrasonic excitation voltage.

[0058] Step S3: Establish a power profile model and collect the working parameters of the ultrasonic system during the welding process.

[0059] Preferably, establishing the power profile model in step S3 includes:

[0060] Step S 31 In the system learning stage, the excitation voltage and welding force in the basic welding process parameters are used as input, and the power is used as output. In the constant voltage source system, the transducer vibration speed remains unchanged, and the output power W∝V 2 / R m ;

[0061] Where W is the output power, V is the excitation voltage, R m is the transducer impedance;

[0062] S 32 , the transducer load impedance and pressure satisfy: f(p) = F(Rm), f(V, F) = F(P);

[0063] Where f(p) is power, F(Rm) is impedance, f(V, F) is the excitation voltage and welding force, and F(P) is welding power.

[0064] Step S 33 , fit the power changes during the welding process to obtain the welding process power profile model.

[0065] The power profile model here is mainly used to assess whether there are abnormalities in the welding process (foreign matter, oxidation, etc.). Generally speaking, if the power does not reach the sample welding power at the same time point, there must be an abnormality in the welding material or fixture.

[0066] The above step S 31 Go to step S 33 It is carried out in the system learning stage, which is the process of collecting the user's data in the traditional welding process and forming a contour model.

[0067] During welding, the system applies the excitation voltage and welding force to the user-set value. Based on the characteristics of the material being welded, the system outputs the power changes during the welding process. The system records the power change curves during the welding process multiple times (as shown in Figures 3 and 4).

[0068] The contour calculation method is based on the theory of data statistics. The mean ave and standard deviation σ of all data at the same time are calculated according to the time-collected data, and the offset n.

[0069] The preset upper limit = ave + n*σ, and the preset lower limit = ave - n*σ. The preset upper limit is compared with the maximum value (max) of this set of data. If the preset upper limit is greater than the maximum value (max) of this set of data, the upper limit is set to the preset upper limit value; otherwise, the maximum value (max) of this set of data is set as the upper limit value.

[0070] Compare the preset lower limit with the minimum value min of this set of data. If the preset lower limit is less than the minimum value min of this set of data, the preset lower limit is set to the preset lower limit value. Otherwise, the minimum value min of this set of data is set as the lower limit value. Fit the upper and lower limits according to the time coordinate respectively, and finally obtain the upper and lower limits.

[0071] Step S4: Determine whether the working parameters meet the expected welding conditions; if so, proceed to step S s ; If not, go to step S6.

[0072] Preferably, the step S4 includes: establishing power state detection points under the time axis, with the time end point serving as a key detection point.

[0073] The power state detection point here can be set to one or more detection points.

[0074] Furthermore, the step S4 also includes: when during the welding process, the key detection point falls within the power contour model, and the remaining at least two power state detection points fall within the power contour model, it is determined that the welding meets the expected requirements, and the process proceeds to the following step S5.

[0075] Furthermore, the step S4 also includes: when during the welding process, the key detection point and more than one power state detection point do not fall within the power contour model (that is, they do not fall within the power model established in the machine learning stage), it is judged that the welding does not meet the expected requirements, and the process proceeds to the following step S6.

[0076] Step S5: Execute the normal welding process and proceed to the final welding stage.

[0077] Step S6: Execute the welding process with preset welding parameters to proceed to the final welding stage.

[0078] Particularly, in the final welding stage, the welding end point is controlled according to the ultrasonic energy or welding type variables in the final welding stage before the intelligent control system is turned on.

[0079] According to the above steps, the ultrasonic bonding process control method of the present invention maintains a certain pressure at the beginning of welding, first starts oscillation, and when welding begins, the ultrasonic system works to reach a certain welding voltage, so that the ultrasonic system forms resonance.

[0080] Then, pre-welding is performed, where the welding pressure is linearly changed over a period of time under a certain ultrasonic excitation voltage. The purpose of the pre-welding stage is to remove the oxide layer or surface contaminants of the material.

[0081] Finally, the normal welding stage is carried out, the ultrasonic wave reaches the normal welding excitation voltage, and welding is carried out for a period of time.

[0082] In summary, the ultrasonic bonding process control method of the present invention has the following advantages:

[0083] 1. The quality control of the ultrasonic welding process is directly coordinated with the control controller of the ultrasonic generator, thereby improving the response speed;

[0084] 2. It is conducive to ensuring welding quality.

[0085] For those skilled in the art, the above invention disclosure is intended only as an example and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0086] At the same time, this application uses specific terms to describe the embodiments of this application, such as "one embodiment," "an embodiment," and / or "some embodiments" to refer to a certain feature, structure, or characteristic related to at least one embodiment of this application.

[0087] Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned two or more times in different places in this specification does not necessarily refer to the same embodiment.

[0088] Furthermore, certain features, structures, or characteristics in one or more embodiments of the present application may be appropriately combined.

[0089] Similarly, it should be noted that in order to simplify the description disclosed in this application and thereby aid in the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, multiple features are sometimes combined into one embodiment, drawing or description thereof.

[0090] However, this method of disclosure does not imply that the subject matter of the application requires more features than are recited in the claims. Indeed, an embodiment may feature less than all features of a single disclosed embodiment.

[0091] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. An ultrasonic bonding process control method, characterized in that, The ultrasonic bonding process control method includes the following steps: S1. When starting welding, the ultrasonic system operates, reaches and maintains the set welding voltage to make the ultrasonic system resonate; S2. Conduct the pre-welding stage under the preset ultrasonic excitation voltage; S3. Establish a power profile model and collect the working parameters of the ultrasonic system during the welding process; S4. Determine whether the working parameters meet the expected welding; if so, proceed to step S5; if not, proceed to step S6; S5. Execute the normal welding process and conduct the final welding stage; S6. Execute the welding process with preset welding parameters and conduct the final welding stage.

2. The ultrasonic bonding process control method according to claim 1, characterized in that The step S1 includes the following steps: S 11 、User preset welding parameters: Before the ultrasonic intelligent control system is turned on, welding tests are carried out as samples for machine learning; S 12 The machine starts to vibrate using the preset welding parameters.

3. The ultrasonic bonding process control method according to claim 2, wherein The welding parameters include the current, welding force, and welding time during the welding process.

4. The ultrasonic bonding process control method according to claim 3, characterized in that The welding parameters also include the current, voltage, welding force, peak power, and electrical energy during the welding process in the pre-welding stage and the final welding stage.

5. The ultrasonic bonding process control method according to claim 2, wherein The establishment of the power profile model in the step S3 includes: S 31 , taking the excitation voltage and welding force in the basic welding process parameters as inputs and the power as the output, In a constant voltage source system, the vibration velocity of the transducer remains unchanged, and the output power W ∝ V 2 / R m ; Wherein, W is the output power, V is the excitation voltage, and R m is the transducer impedance; S 32 The transducer load impedance and pressure satisfy: f(p) = F(Rm), f(V, F) = F(P); Wherein, f(p) is the power, F(Rm) is the impedance, f(V, F) is the excitation voltage and the welding force, and F(P) is the welding power; S 33 、Fit the change of power during the welding process to obtain the power profile model of the welding process.

6. The ultrasonic bonding process control method according to claim 2, wherein The step S4 includes: establishing power state detection points under the time axis, and the end point of time is used as the key detection point.

7. The ultrasonic bonding process control method according to claim 6, characterized in that, The step S4 includes: during the welding process, when the key detection point falls within the power profile model and at least two other power state detection points fall within the power profile model, it is determined that the expected welding is met.

8. The ultrasonic bonding process control method according to claim 6, wherein, The step S4 includes: during the welding process, when the key detection point and more than one power state detection point do not fall within the power profile model, it is determined that the expected welding is not met.

9. The ultrasonic bonding process control method according to claim 6, characterized in that, In the final welding stage, control the welding end point according to the ultrasonic energy in the final welding stage before the intelligent control system is turned on or the welding deformation amount.

10. The ultrasonic bonding process control method according to claim 6, wherein, The power state detection point is one or more detection points.

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