Soldering process monitoring system and method

Abstract

The present disclosure provides a soldering process monitoring system and method. The soldering process monitoring system includes a tin feeding unit, a soldering iron, a temperature sensing unit, and a processing unit. The tin feeding unit is configured to provide tin material. The soldering iron has an end portion, wherein the end portion is heated to melt the tin material when in contact with the tin material. Within a first time period after the end portion contacts the tin material, the temperature of the end portion decreases by a first variation, and during the process of the end portion contacting the tin material, the temperature of the end portion decreases by a second variation. The processing unit obtains the first and second variations through the temperature sensing unit, and calculates the temperature drop rate of the end portion in the first time period, and compares the temperature drop rate and the second variation with a first reference value and a second reference value, respectively, and outputs a monitoring signal based on the comparison result.

Description

Technical Field

[0001] The present disclosure relates to a soldering process monitoring system and method, and more particularly to a soldering process monitoring system and method capable of understanding solder quality in real time. Background Art

[0002] The soldering process uses a high-temperature soldering iron tip to melt the lower-melting-point solder metal, thereby joining metal workpieces. Solder quality is closely related to details in the process, including whether the soldering iron actually melts the solder, and whether the amount of solder melted and the residual solder are consistent with expectations.

[0003] Conventional technology requires inspection using automated optical inspection (AOI) and other visual equipment to confirm solder quality after the soldering process is complete. However, existing technology cannot monitor and adjust quality in real time during the soldering process, which affects soldering process efficiency. Furthermore, the cost of visual inspection equipment is high, increasing costs.

[0004] Therefore, it is an urgent need to develop a soldering process monitoring system and method that can improve the above-mentioned prior art. Summary of the Invention

[0005] The present disclosure aims to provide a soldering process monitoring system and method. During the soldering process, these systems monitor solder quality by measuring the temperature changes at the tip of the soldering iron. This allows for real-time detection and adjustment of poor solder quality, effectively improving the quality stability and operational efficiency of the soldering process. Furthermore, this system eliminates the need for additional visual inspection equipment, saving costs.

[0006] To achieve the above-mentioned purpose, the present disclosure provides a soldering process monitoring system, comprising a tin feeding unit, a soldering iron, a temperature sensing unit and a processing unit. The tin feeding unit is configured to provide tin material. The soldering iron has an end, wherein the end is heated to melt the tin material when it contacts the tin material. In a first time period after the end contacts the tin material, the temperature of the end decreases by a first change amount, and in the process of the end contacting the tin material, the temperature of the end decreases by a second change amount. The temperature sensing unit is configured to sense the temperature of the end of the soldering iron to obtain multiple temperature information. The processing unit is connected to the temperature sensing unit to receive the temperature information and calculate the first change amount and the second change amount based on the temperature information. The processing unit calculates the temperature drop rate of the temperature of the end in the first time period, and compares the temperature drop rate and the second change amount with the first reference value and the second reference value respectively, and outputs a monitoring signal based on the comparison result.

[0007] To achieve the above-mentioned objectives, the present disclosure further provides a soldering process monitoring method, comprising the steps of: (a) continuously sensing the temperature of the end of the soldering iron; (b) heating the end and bringing the tin into contact with the end, wherein within a first time period after the end contacts the tin, the temperature of the end is sensed to obtain a plurality of temperature information; (c) calculating a first change in temperature drop within the first time period based on the temperature information, and calculating a temperature drop rate within the first time period; (d) comparing the temperature drop rate with a first reference value, and outputting a first monitoring signal based on the comparison result; (e) separating the tin from the end, wherein during the process of the end contacting the tin, the temperature of the end is sensed and a plurality of temperature information is obtained; and (f) calculating a second change in temperature drop of the end based on the temperature information, comparing the second change with a second reference value, and outputting a second monitoring signal based on the comparison result. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Schematic diagram of the structure of the soldering process monitoring system according to the preferred embodiment of the present disclosure.

[0009] Figure 2 This is a schematic diagram of the soldering process.

[0010] Figure 3 This is a schematic diagram of the temperature change at the tip of the soldering iron during the soldering process.

[0011] Figure 4 1 is a flow chart of a soldering process monitoring method according to a preferred embodiment of the present disclosure.

[0012] The description of the accompanying drawings is as follows:

[0013] 1: Tin feeding unit

[0014] 11: Tin

[0015] 2: Soldering iron

[0016] 21: End

[0017] 3: Temperature sensing unit

[0018] 4: Temperature controller

[0019] 5: Pins

[0020] 6: Solder points

[0021] 7: Processing unit

[0022] (a), (b), (c), (d), (e): Action status

[0023] Δt1: first time period

[0024] Δt2: second time period

[0025] T1: first change

[0026] T2: Second change

[0027] T3: The third change

[0028] V1: Temperature drop rate

[0029] V2: Temperature recovery speed

[0030] average value

[0031] σ V1 , σ T2 , σ V2 : Standard deviation

[0032] S1, S2, S3, S4, S5, S6, S7, S8: Steps DETAILED DESCRIPTION

[0033] Some typical embodiments that embody the features and advantages of the present disclosure will be described in detail in the following description. It should be understood that the present disclosure is capable of various variations in different implementations without departing from the scope of the present disclosure, and that the descriptions and illustrations therein are intended to be illustrative in nature and not to limit the present disclosure.

[0034] Figure 1 FIG. 1 is a schematic diagram of the structure of the soldering process monitoring system according to the preferred embodiment of the present disclosure. Figure 1 As shown, the soldering process monitoring system includes a soldering iron 2, a temperature sensing unit 3, and a processing unit 7. The soldering iron 2 includes a soldering iron end 21, which is heated to melt the solder 11 upon contact. The temperature sensing unit 3 senses the temperature of the soldering iron end 21 using a contact or non-contact method. The temperature sensing unit 3 is connected to the processing unit 7 and transmits the sensed temperature information of the soldering iron end 21 to the processing unit 7 for processing. In some embodiments, the soldering process monitoring system further includes a temperature controller 4, which is connected to the soldering iron 2 and configured to control the temperature of the soldering iron end 21.

[0035] Taking the soldering process applied to a printed circuit board as an example, the specific monitoring method of the soldering process monitoring system disclosed in the present invention is described as follows.

[0036] During the soldering process, the pin 5 of the electronic component passes through the solder joint 6 of the printed circuit board, and solder is used to fuse the pin 5 and the solder joint 6. For a breakdown of the soldering process, please refer to Figure 2, which illustrates the action states at different time points during the soldering process, in order of action states (a), (b), (c), (d) and (e). During the soldering process, the temperature change of the end 21 of the soldering iron 2 is as follows Figure 3 shown, and Figure 3 The time point or time period corresponding to each action state is also marked.

[0037] First, during the preparatory action, the end 21 of the soldering iron 2 and the tin material 11 provided by the tin feeding unit 1 do not contact the solder joint 6 (e.g. Figure 1 As shown), the end portion 21 may be heated in advance.

[0038] Next, as shown in operating state (a), the tip 21 of the soldering iron 2 contacts the solder joint 6, maintaining the temperature of the tip 21 at a high temperature, which in turn increases the temperature of the solder joint 6. At this time, the tin material 11 provided by the solder feeding unit 1 remains at a certain distance from the tip 21 and the solder joint 6.

[0039] Next, as shown in action state (b), the tin feeding unit 1 supplies tin 11, causing the tin 11 to contact the end portion 21 or the solder joint 6. After the time point corresponding to action state (b), the tin 11 in contact with the end portion 21 or the solder joint 6 is melted by the high temperature, and the temperature of the end portion 21 decreases due to the melting of the tin 11. Specifically, within a first time period Δt1 after the tin 11 contacts the end portion 21 or the solder joint 6, the temperature of the end portion 21 decreases by a first variation T1. This first variation T1 can be obtained by the temperature sensing unit 3 by sensing the temperature of the end portion 21 and then transmitting it to the processing unit 7 through multiple temperature information measured at different times. The processing unit 7 then calculates and obtains the temperature drop rate of the end portion 21 within the first time period Δt1. The temperature drop rate is equal to the first variation T1 divided by the first time period Δt1. The first time period Δt1 can be, for example, but not limited to, equal to one unit time. Since the end portion 21 may be normally melted, not melted, or cold-welded, and the temperature drop rates corresponding to each situation are different, the processing unit 7 can compare the temperature drop rate with a first reference value and output a first monitoring signal based on the comparison result, wherein the first monitoring signal reflects whether the end portion 21 is indeed melted.

[0040] Next, as shown in the operating state (c), the tin feeding unit 1 continues to supply the tin material 11 , and the temperature of the end portion 21 continues to drop.

[0041] Then, as shown in action state (d), the tin delivery unit 1 has reached the preset tin amount, and the tin delivery unit 1 stops supplying tin 11, separating the tin 11 from the end portion 21 and the solder joint 6. During the process of the tin 11 contacting the end portion 21 or the solder joint 6, the temperature of the end portion 21 decreases by a second variation T2. This second variation T2 can be obtained by the temperature sensing unit 3 by sensing the temperature of the end portion 21 and transmitting it to the processing unit 7 through multiple temperature information measured at different times, and then calculated by the processing unit 7. Because the second variation T2 is related to the total amount of tin 11 melted by the end portion 21, the processing unit 7 can compare the second variation T2 with a second reference value and output a second monitoring signal based on the comparison result. The second monitoring signal reflects whether the total amount of tin 11 melted by the end portion 21 matches the preset tin amount.

[0042] Finally, as shown in the action state (e), when the end portion 21 separates from the solder joint 6 , the temperature of the end portion 21 begins to rise, and part of the previously melted tin material 11 may remain on the end portion 21 .

[0043] In this way, during the soldering process, the temperature changes at the end 21 can be used to determine in real time whether there are problems such as solder deficiency or leaks, thereby monitoring solder quality. Poor solder quality can be detected in real time through the monitoring signal and adjusted accordingly, effectively improving the quality stability and operating efficiency of the soldering process. Furthermore, the present disclosure eliminates the need for additional visual equipment for quality inspection, saving costs.

[0044] Furthermore, within a second time period Δt2 after the time point corresponding to action state (d), i.e., within the second time period Δt2 after the tin material 11 separates from the end portion 21 or the solder joint 6, the temperature of the end portion 21 increases by a third variation T3. This third variation T3 can be calculated by the temperature sensing unit 3 by sensing the temperature of the end portion 21 and transmitting multiple temperature information measured at different times to the processing unit 7. The temperature sensing unit 3 then transmits this temperature information to the processing unit 7, which further calculates the temperature recovery rate of the end portion 21 within the second time period Δt2. The temperature recovery rate is equal to the third variation T3 divided by the second time period Δt2. The second time period Δt2 can be, for example, but not limited to, equal to one unit time. The temperature recovery rate is related to the total amount of tin material 11 remaining on the end portion 21, and the total amount of tin material 11 remaining on the end portion 21 affects the effective soldering amount on the solder joint 6. Therefore, the processing unit 7 can compare the temperature recovery rate with the third reference value and output a third monitoring signal based on the comparison result, wherein the third monitoring signal reflects whether the total amount of tin material remaining on the end 21 is consistent with the preset residual tin amount, thereby estimating the effective tin amount on the solder joint 6 and further determining whether there is a problem such as missing solder or leaking solder.

[0045] The aforementioned first, second, and third reference values can be obtained by statistically analyzing the temperature drop rate, second change, and temperature recovery rate under ideal soldering process conditions. The method for comparing the reference values with their corresponding temperature change rates or changes can also be determined based on actual needs. A specific example is provided below.

[0046] Using the same pin and solder joint conditions, the soldering process was performed over 30 times. During each soldering process, the tip 21 of the soldering iron 2 melted 5 mm of solder, and no residual solder remained on the tip 21. The temperature drop rate V1, second change T2, and temperature recovery rate V2 during all soldering processes are recorded in Table 1.

[0047] Table 1

[0048] order V1(degC / sec) T2(degC) V2(degC / sec) 1 0.0434 6.9 0.01620 2 0.0514 6.7 0.01277 3 0.0427 7.0 0.01528 4 0.0410 6.5 0.01517 5 0.0441 5.5 0.01538 … … … … 30 0.0364 6.3 0.01310

[0049] According to Table 1, the average values and standard deviations of the temperature drop rate V1, the second change T2, and the temperature rise rate V2 can be calculated by using equations (1) and (2), as shown in Table 2.

[0050]

[0051]

[0052] Where x is the target value (i.e., the temperature drop rate V1, the second change T2, or the temperature recovery rate V2), is the average of the target values, n is the total number of experiments, i represents the order, xi is the target value for the corresponding order, and σ is the standard deviation of the target value. The calculated average and standard deviations of the temperature drop rate V1, the second change T2, and the temperature recovery rate V2 are listed in Table 2.

[0053] Table 2

[0054] / V1 T2 V2 average value 0.0408 6.3368 0.0137 Standard deviation 0.0033 0.4132 0.0015

[0055] According to Table 2, the first reference value, the second reference value, and the third reference value can be set as the average values of the temperature drop rate V1, the second change T2, and the temperature rise rate V2, respectively. and The corresponding standard deviations are σ V1 , σ T2 and σ V2 When monitoring the soldering process in the future, the reference value can be used as a benchmark for comparison, and the allowable error range can be set according to the corresponding standard deviation. For example, during the soldering process, if When , it means that the end 21 of the soldering iron 2 is normally molten; when the preset molten tin amount is the same as 5mm, if It means that the amount of molten tin at the end 21 is normal; if This means that there is no residual tin on the end portion 21. Of course, the actual comparison method is not limited to this and can be adjusted according to actual needs.

[0056] Figure 4 This is a flow chart of a soldering process monitoring method according to a preferred embodiment of the present disclosure, wherein the soldering process monitoring method can be applied to Figure 1 The soldering process monitoring system shown in FIG. Figure 4 As shown, the soldering process monitoring method includes the following steps.

[0057] First, in step S1 , the temperature of the end portion 21 of the soldering iron 2 is continuously sensed.

[0058] Next, in step S2 , the end portion 21 is heated and the tin material 11 is brought into contact with the end portion 21 . Within a first time period Δt1 after the end portion 21 contacts the tin material 11 , the temperature sensing unit 3 senses the temperature of the end portion 21 and transmits the sensed temperature information to the processing unit 7 .

[0059] In step S3 , the processing unit 7 calculates a first change T1 of the temperature drop of the end portion 21 and a temperature drop rate of the end portion 21 within a first time period Δt1 according to the plurality of temperature information.

[0060] Next, in step S4 , the processing unit 7 compares the temperature drop rate with a first reference value, and outputs a first monitoring signal according to the comparison result, wherein the first monitoring signal reflects whether the end portion 21 has indeed melted the tin material 11 .

[0061] Then, in step S5 , the tin material 11 is separated from the end portion 21 . During the contact between the end portion 21 and the tin material 11 , the temperature sensing unit 3 continuously senses the temperature of the end portion 21 and transmits the sensed temperature information to the processing unit 7 .

[0062] Finally, in step S6, the processing unit 7 calculates a second change T2 of the temperature drop of the end portion 21 based on the plurality of temperature information, compares the second change T2 with a second reference value, and outputs a second monitoring signal based on the comparison result, wherein the second monitoring signal reflects whether the total amount of the tin material 11 melted at the end portion 21 is consistent with the preset tin melting amount.

[0063] Furthermore, the temperature of the end portion 21 rises during a second time period Δt2 after the end portion 21 is separated from the tin material 11 in step S5. In some embodiments, the soldering process monitoring method further includes step S7: during the second time period Δt2 after the end portion 21 is separated from the tin material 11, the temperature sensing unit 3 senses the temperature of the end portion 21 and transmits a plurality of temperature information sensed to the processing unit 7; and step S8: the processing unit 7 calculates a third change T3 of the temperature rise of the end portion 21 based on the plurality of temperature information, calculates a temperature recovery rate of the end portion 21 during the second time period Δt2, compares the temperature recovery rate with a third reference value, and outputs a third monitoring signal based on the comparison result. After the end portion 21 is separated from the tin material 11, a portion of the melted tin material 11 at the end portion 21 remains on the end portion 21. The third monitoring signal reflects whether the total amount of tin remaining on the end portion 21 meets a predetermined residual tin amount.

[0064] In summary, the present disclosure provides a soldering process monitoring system and method. During the soldering process, these systems monitor solder quality by observing temperature changes at the tip of the soldering iron. This allows for real-time detection and adjustment of poor solder quality, effectively improving the quality stability and operational efficiency of the soldering process. Furthermore, this system eliminates the need for additional visual inspection equipment, saving costs.

[0065] It should be noted that the above description is merely a preferred embodiment for the purpose of illustrating the present disclosure. The present disclosure is not limited to the described embodiment. The scope of the present disclosure is determined by the claims. Furthermore, the present disclosure is subject to various modifications as conceived by those skilled in the art, without departing from the scope of the claims.

Claims

1. A soldering process monitoring system comprising: A tin feeding unit is configured to provide a tin material; A soldering iron having an end portion, wherein the end portion is heated to melt the tin when in contact with the tin, wherein the temperature of the end portion decreases by a first amount within a first period of time after the end portion contacts the tin, and the temperature of the end portion decreases by a second amount while the end portion is in contact with the tin; a temperature sensing unit configured to sense the temperature of the end portion of the soldering iron to obtain a plurality of temperature information; as well as a processing unit connected to the temperature sensing unit to receive the temperature information and calculate the first change amount and the second change amount based on the temperature information, wherein the processing unit calculates a temperature drop rate of the temperature of the end portion within the first time period, compares the temperature drop rate and the second change amount with a first reference value and a second reference value, respectively, and outputs a monitoring signal based on the comparison result; The first reference value and the second reference value are obtained by statistically calculating the temperature drop rate, the second variation, and a temperature rise rate under an ideal soldering process state. In which, within a second time period after the end portion is separated from the tin material, the temperature of the end portion rises by a third variation. The temperature sensing unit obtains multiple pieces of temperature information by sensing the temperature of the end portion. The processing unit receives the temperature information and calculates the third variation based on the temperature information, and calculates a temperature recovery rate of the temperature of the end portion within the second time period. The processing unit compares the temperature recovery rate with a third reference value and outputs a third monitoring signal based on the comparison result. The third reference value is obtained by statistically calculating the temperature drop rate, the second variation, and the temperature recovery rate under an ideal soldering process state.

2. The soldering process monitoring system according to claim 1, wherein: The monitoring signal includes a first monitoring signal. The processing unit outputs the first monitoring signal according to a comparison result of the temperature drop rate and the first reference value. The first monitoring signal reflects whether the end portion has indeed melted the tin material.

3. The soldering process monitoring system according to claim 1, wherein: The monitoring signal includes a second monitoring signal. The processing unit outputs the second monitoring signal based on the comparison result of the second variation and the second reference value. The second monitoring signal reflects whether the total amount of the tin material melted at the end is consistent with a preset tin melting amount.

4. The soldering process monitoring system according to claim 1, wherein: After the end portion is separated from the tin material, a portion of the tin material melted by the end portion remains on the end portion. The third monitoring signal reflects whether the total amount of the tin material remaining on the end portion is consistent with a preset residual tin amount.

5. A soldering process monitoring method comprising: (a) continuously sensing the temperature of one end of a soldering iron; (b) heating the end portion and bringing a tin material into contact with the end portion, wherein: Within a first time period after the end portion contacts the tin material, sensing the temperature of the end portion to obtain a plurality of temperature information; (c) calculating a first change in temperature drop during the first time period based on the temperature information, and calculating a temperature drop rate during the first time period; (d) comparing the temperature drop rate with a first reference value, and outputting a first monitoring signal based on the comparison result; (e) separating the tin material from the end portion, wherein, during the process of the end portion and the tin material being in contact, sensing the temperature of the end portion and obtaining a plurality of temperature information; (f) calculating a second change in the end temperature drop based on the temperature information, comparing the second change with a second reference value, and outputting a second monitoring signal based on the comparison result; and (g) within a second time period after the end portion is separated from the tin material, sensing the temperature of the end portion and obtaining a plurality of temperature information, and calculating a third variation of the temperature rise of the end portion based on the temperature information, and calculating a temperature recovery rate of the end portion within the second time period, and comparing the temperature recovery rate with a third reference value, and outputting a third monitoring signal based on the comparison result, wherein the third reference value is obtained by statistically calculating the temperature drop rate, the second variation, and the temperature recovery rate under an ideal soldering process state. The first reference value and the second reference value are obtained by statistically calculating the temperature drop rate, the second variation, and a temperature rise rate under an ideal soldering process state.

6. The soldering process monitoring method according to claim 5, wherein: The first monitoring signal reflects whether the end portion has indeed melted the tin material.

7. The soldering process monitoring method according to claim 5, wherein: The second monitoring signal reflects whether the total amount of the tin material melted at the end portion is consistent with a preset tin melting amount.

8. The soldering process monitoring method according to claim 6, wherein: After the end portion is separated from the tin material, a portion of the tin material melted by the end portion remains on the end portion. The third monitoring signal reflects whether the total amount of the tin material remaining on the end portion is consistent with a preset residual tin amount.

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