JP5838580B2 - Solder bend detection device - Google Patents

Description

The present invention relates to a solder bending detection device.

  Conventionally, soldering using an automatic thread soldering device has been performed on printed circuit boards and the like. When an automatic yarn soldering device is used, for example, if a defect occurs in the supply control of the yarn solder, solder clogging may occur in the solder supply unit provided in the automatic yarn soldering device, or the soldering position may shift. . For example, Patent Document 1 is known as one that can detect such a solder failure. When soldering a chip using thread solder (solder wire), the thread solder is brought into contact with the chip. That is, when both are not in contact, appropriate soldering cannot be performed. Therefore, in Patent Document 1, yarn solder as a contact body is brought into contact with a chip that is an object, and contact between the solder wire and the chip is detected based on a change in voltage at that time.

JP 2005-227112 A

  However, various solder states that cause solder defects are assumed. For this reason, simply judging the contact between the thread solder and the tip, it is possible to determine what causes, more specifically, what kind of state the solder is in and the solder failure has occurred. It was difficult to do. It is necessary to grasp the state of the solder when a solder failure occurs in order to efficiently perform the soldering operation. In particular, lead-free solder, which has been frequently used in recent years, has a high melting point, and solder clogging is likely to occur compared to leaded solder. In addition, when soldering using lead-free solder, the tip of the thread solder may be bent because the tip of the thread solder supplied from the solder supply unit comes into contact with the solder hand tip or the pin of the electronic component on the workpiece side. , Easy to be spherical. Even when lead-free solder having such characteristics is used, it is necessary to grasp the state of the solder in order to perform the soldering work efficiently.

Therefore, an object of the solder bending detection device disclosed in this specification is to detect the state of the solder , in particular, the bending .

The solder bend detection device disclosed in this specification includes an electrode disposed oppositely across a solder supply position to which solder is supplied from a solder supply unit, and a static between the electrode and the solder supplied from the solder supply unit. Capacitance value acquisition means for acquiring a capacitance value, a balance of capacitance values acquired for each of the electrodes by the capacitance value acquisition means, and a change amount of the capacitance value with respect to a solder feed amount A calculation unit that determines a bending of the solder supplied from the solder supply unit based on a result of comparing a certain capacitance change amount with a change amount when the solder is normal ;

  The electrode forms a capacitor together with the solder supplied to the solder supply unit, and the calculation unit can determine the state of the solder based on the capacitance value. For example, when the distance between the electrode and the solder is narrow due to the bending of the solder, the capacitance value increases. On the other hand, when the distance between the electrode and the solder is wide, the capacitance value is small. Thereby, the calculating part can detect the state of solder.

According to the solder bending detection device disclosed in the present specification, it is possible to detect the state of the solder , in particular, the bending .

1A and 1B are explanatory views showing a state of solder that can occur in solder supplied from a solder supply unit, FIG. 1A is a normal state, FIG. 1B is a state where the tip of the solder is spherical, FIG. 1C shows a state where the tip of the solder is bent, and FIG. 1D shows a state where the solder is clogged. FIG. 2 is an explanatory diagram showing the relationship between solder supply holes and solder provided in the solder supply unit. FIG. 3 is an explanatory diagram illustrating a schematic configuration of the automatic soldering apparatus according to the embodiment. FIG. 4A is an explanatory view showing the tip portion of the solder supply portion, and FIG. 4B is an explanatory view of the solder supply portion as viewed from the front end side. FIG. 5 is an explanatory diagram showing an equivalent circuit of a circuit formed in the solder state detection device. FIG. 6 is an explanatory diagram showing an equivalent circuit when the solder is bent. FIG. 7A is an explanatory diagram illustrating a state where the amount of solder supplied from the solder supply unit is small, and is an explanatory diagram illustrating a state where the amount of solder supplied from the solder supply unit is large. FIG. 8A is an explanatory diagram showing a capacitance bridge circuit formed in the solder state detection device, and FIG. 8B is a block diagram of the solder state detection device. FIG. 9 is an example of a solder state determination table. FIG. 10 is a flowchart showing an example of control of the automatic soldering apparatus. FIG. 11 is a schematic diagram showing another example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, and the like of each part may not be shown so as to completely match the actual ones.

  First, the state of the solder that may occur in the solder supplied from the solder supply unit 13a will be described with reference to FIGS. 1 (A) to 1 (D). FIG. 1A shows a state in which the solder 1 is normally supplied through a solder supply hole 13a1 provided in the solder supply unit 13. FIG. 1B shows a state in which the tip of the solder 1 supplied through the solder supply hole 13a1 is spherical. FIG. 1C shows a state in which the tip of the solder 1 supplied through the solder supply hole 13a1 is bent. FIG. 1D is a view showing a state in which the solder 1 supplied through the solder supply hole 13a1 is clogged in the solder supply hole 13a1.

Referring to FIG. 2, the diameter of the solder supply hole 13a1 provided in the solder supply unit 13a is W2, which is larger than the diameter W1 of the solder 1. For this reason, a gap may be formed between the solder 1 and the inner peripheral wall of the solder supply hole 13a1. For this reason, the solder may swing and a solder state as shown in FIGS. 1B to 1D may be created. These solder states cause a solder failure.

  FIG. 3 is an explanatory diagram showing a schematic configuration of the automatic soldering device 10 including the solder state detecting device 100 of the present embodiment. FIG. 4A is an explanatory view showing a tip portion of the solder supply unit 13a, and FIG. 4B is an explanatory view of the solder supply unit 13a viewed from the tip side. FIG. 5 is an explanatory diagram showing an equivalent circuit 110 of a circuit formed in the solder state detection device 100.

  The automatic soldering apparatus 10 solders electronic parts 12a to 12d and the like to the target workpiece 11. The automatic soldering device 10 includes a solder supply device 13. The solder supply device 13 includes a solder supply unit 13a. The solder supply unit 13a1 supplies the solder 1 set in the solder supply device 13 to the solder supply position P shown in FIG. The solder supply device 13 adjusts the feed amount of the solder 1.

  The solder supply unit 13 a is mounted on the moving stage 14. The moving stage 14 moves the solder supply unit 13a in the X direction and the Y direction based on a command from the moving stage controller 14a. Further, the moving stage 14 includes a mechanism for changing the inclination of the solder supply unit 13a. Note that the solder supply device 13 can move in the Z direction, and can approach and leave the target workpiece 11.

  The automatic soldering apparatus 10 includes a solder heating unit 15. The solder heating unit 15 melts the solder 1 with a laser. The solder heating unit 15 can use a hand instead of a laser.

The automatic soldering device 10 includes a solder state detection device 100. The solder state detection device 100 functions as a solder bending detection device. The solder state detection device 100 includes electrodes 101a, 101b, 101c, and 101d arranged on the side of the solder supply position P. The electrodes 101a, 101b, 101c, and 101d are supported by the solder supply unit 13a through the frame 13b. In this embodiment, the number of electrodes is four, but the number of electrodes may be other numbers. Each of the electrodes 101a to 101d is coated with a resin. More specifically, it is coated with an acrylic resin. By being resin-coated, it is possible to avoid a short circuit when contacting the solder 1 or the target workpiece 11. Further, the dielectric constant can be improved, and the accuracy of detection of a solder state, which will be described in detail later, is improved. Further, the occurrence of corrosion due to the solder flux adhering to the electrode is suppressed, and it is advantageous in terms of cleaning.

  The electrodes 101a, 101b, 101c, and 101d are arranged to face each other with the solder supply position P in between. Specifically, the electrode 101a and the electrode 101c are arranged to face each other, and the electrode 101b and the electrode 101d are arranged to face each other. By arranging the electrodes in this manner, it can be determined whether the solder 1 is bent or not, and whether the solder 1 is thick or thin. This will be described in detail later.

FIG. 5 is an explanatory diagram showing an equivalent circuit 110 of a circuit formed in the solder state detection device 100. Each of the electrodes 101 a to 101 b forms capacitors 111 a to 111 d together with the solder 1 supplied from the solder supply unit 103. When the capacitor has an area S, an electrode plate distance d, and a dielectric constant ε, its capacitance C (F) is
C = ε (S / d)
It can be expressed. This
d = ε (S / C)
It can be expressed as.

In the equivalent circuit 110, when the solder 1 is disposed at the center of each of the electrodes 101a to 101b, the capacitance values Ca, Cb, Cc, and Cd in the capacitors 111a to 111d have the same value. For example, when the tip of the solder 1 is bent and the distance between the electrode plates of the capacitor 111d is increased as shown in FIG. 6 and the distance between the electrode plates of the capacitor 111a facing this is reduced, each capacitance value is It becomes as follows. That is,
Ca = Cc, Cb> Cd
It becomes.

  Thus, the state of the solder 1 can be detected by using the balance of capacitance values. For example, as shown in FIG. 1B, when the amount of the solder 1 is large and the solder 1 becomes spherical, the solder 1 approaches the electrodes 101a to 101b, and thus the capacitors 111a to 111d. The value of becomes larger than the normal value. The case where the amount of solder 1 is small can be detected in the same manner.

  Further, for example, as shown in FIG. 7A, when the amount of the solder 1 is small, the area S is small, so the capacitance value is small. On the contrary, as shown in FIG. 7B, when the amount of the solder 1 is too large, the area S becomes large, and the capacitance value becomes large. In this way, the state relating to the amount of solder 1 can also be detected. As shown in FIG. 1D, when the solder 1 is clogged in the solder supply hole 13a1, the capacitance value is zero. More specifically, if the capacitance value is 0 even though the solder supply device performs the solder supply operation based on a command from the control PC 102 described later, the solder supply hole 13a1 It can be determined that the solder is clogged.

  The solder state detection apparatus 100 includes a control PC (personal computer) 102 as a calculation unit. The control PC 102 not only performs calculations for the solder state detection by the solder state detection device 100 but also controls the automatic solder device 10. For this reason, it is electrically connected to the solder supply device 13 and also controls the solder supply device 13. Accordingly, the control PC 102 also instructs the feed amount of the solder 1. Further, it is electrically connected to the moving stage controller 14a, and also instructs the moving stage controller 14a. Further, the control PC 102 is also electrically connected to the solder heating unit 15.

  The control PC 102 is provided with an alarm device 102a and a return switch 102b. The alarm device 102a issues an alarm when it detects a state that requires adjustment and return work by the operator. The return switch 102b is a switch that is pressed by the operator when the return work by the operator is completed and returns to the automatic soldering process.

  The solder state detection device 100 includes capacitance bridge circuits (hereinafter referred to as “capacitance bridges”) 103a to 103d shown in FIG. The capacitors 111a to 111d described above are incorporated in the capacitance bridges 103a to 103d, respectively. That is, the capacitance bridge 103a includes a capacitor 111a, and the capacitance bridge 103b includes a capacitor 111b. The capacitance bridge 103c includes a capacitor 111c, and the capacitance bridge 103d includes a capacitor 111d. These capacitance bridges 103 a to 103 d correspond to capacitance acquisition value means for acquiring a capacitance value between the electrodes 101 a to 101 d and the solder 1. The control PC 102 determines the state of the solder 1 supplied from the solder supply unit 13a based on the capacitance value acquired by the capacitance bridges 103a to 103d corresponding to the capacitance acquisition means.

  FIG. 8B is a block diagram of the solder state detection device 100. The solder state detection device 100 includes the capacitance bridges 103a to 103d as described above. Further, a comparator Cmp_A, a comparator Cmp_B, a comparator Cmp_C, and a comparator Cmp_D are provided. Further, a comparator Cmp_AC and a comparator Cmp_BD are provided.

  The comparator Cmp_A compares the voltage calculated based on the capacitance value Ca obtained by the capacitance bridge 103a with the reference voltage output from the control PC 102. Here, the reference voltage is a voltage value calculated based on a capacitance value measured in a state where the solder 1 is normally supplied as shown in FIG. The reference voltage is input to the comparator Cmp_A through the digital / analog converter DAC_A. The output of the comparator Cmp_A is returned to the control PC 102. Further, the value obtained by the capacitance bridge 103a is input to the control PC 102 via the analog-digital converter ADC_A.

  The comparator Cmp_B compares the voltage calculated based on the capacitance value Cb obtained by the capacitance bridge 103b with the reference voltage output from the control PC 102. Here, the reference voltage is a voltage value calculated based on a capacitance value measured in a state where the solder 1 is normally supplied as shown in FIG. The reference voltage is input to the comparator Cmp_B via the digital / analog converter DAC_B. The output of the comparator Cmp_B is returned to the control PC 102. Further, the value obtained by the capacitance bridge 103b is input to the control PC 102 via the analog-digital converter ADC_B.

  The comparator Cmp_C compares the voltage calculated based on the capacitance value Cc obtained by the capacitance bridge 103C with the reference voltage output from the control PC 102. Here, the reference voltage is a voltage value calculated based on a capacitance value measured in a state where the solder 1 is normally supplied as shown in FIG. The reference voltage is input to the comparator Cmp_C via the digital / analog converter DAC_C. The output of the comparator Cmp_C is returned to the control PC 102. Further, the value obtained by the capacitance bridge 103c is input to the control PC 102 via the analog-digital converter ADC_C.

  The comparator Cmp_D compares the voltage calculated based on the capacitance value Cd obtained by the capacitance bridge 103d with the reference voltage output from the control PC 102. Here, the reference voltage is a voltage value calculated based on a capacitance value measured in a state where the solder 1 is normally supplied as shown in FIG. The reference voltage is input to the comparator Cmp_D through the digital / analog converter DAC_D. The output of the comparator Cmp_D is returned to the control PC 102. Further, the value obtained by the capacitance bridge 103d is input to the control PC 102 via the analog-digital converter ADC_D.

  The comparator Cmp_AC generates a voltage calculated based on the capacitance value Ca obtained by the capacitance bridge 103a and a voltage calculated based on the capacitance value Cc obtained by the capacitance bridge 103c. Compare. The output of the comparator Cmp_AC is returned to the control PC 102.

  By using the results of the comparators Cmp_A to Cmp_D, it is possible to detect a state in which the solder 1 is too thick, too thin, or in a spherical shape.

The comparator Cmp_BD outputs a voltage calculated based on the capacitance value Cb obtained by the capacitance bridge 103b and a voltage calculated based on the capacitance value Cd obtained by the capacitance bridge 103d. Compare. The output of the comparator Cmp_BD is returned to the control PC 102.

  By using the results of the comparators Cmp_AC and Cmp_BD, it is possible to detect that the tip of the solder 1 is bent.

  In addition, the control PC 102 detects the state of the solder 1 based on the change in the value obtained by the capacitance bridges 103a to 103d, by comparing this with the change in the normal state.

  FIG. 9 is a solder state determination table. When the solder is normal, the balance of the capacitances, that is, the capacitance values of the capacitors arranged opposite to each other substantially coincide. Also, the capacitance value itself naturally shows a normal value. The amount of change in capacitance with respect to the solder feed amount is also the amount of change during normal time.

  On the other hand, when the solder 1 is longer than the specified value, the capacitance values of the capacitors arranged opposite to each other are substantially matched and balanced, but the capacitance value is larger than the normal value. This is because the area S is increased. The amount of change in capacitance with respect to the solder feed amount is the amount of change during normal times.

  When the solder 1 is shorter than the specified value, the capacitance values of the capacitors arranged opposite to each other are substantially matched and balanced, but the capacitance value is smaller than the normal value. This is because the area S becomes small. The amount of change in capacitance with respect to the solder feed amount is the amount of change during normal times.

  In the case where the solder 1 is clogged, the capacitance values are 0 respectively. That is, when the solder 1 is clogged, a capacitance value of 0 is observed even though the control PC issues a solder feed command. Also, the amount of change in capacitance with respect to the solder feed amount is not observed.

  When the solder 1 is bent, the capacitance values of the capacitors disposed opposite to each other are in an unbalanced state. In other words, the capacitance value on the side closer to the solder is increased, and the capacitance value on the separated side is decreased. The capacitance change amount with respect to the solder feed amount also changes differently from the normal time.

  When the solder 1 is in a spherical shape or thicker than usual, the capacitance values of the capacitors disposed opposite to each other are substantially matched and balanced, but the capacitance value is lower than the normal value. Also grows. This is because the solder 1 is approaching each electrode almost equally. Further, the amount of change in capacitance with respect to the solder feed amount is different from the usual amount. This is because the area of the solder facing the electrodes is different from that in the normal state, and the sensitivity to movement is different.

  When the solder 1 is thinner than usual, the capacitance values of the capacitors arranged opposite to each other are substantially matched and balanced, but the capacitance value is smaller than the normal value. This is because the solder 1 is substantially evenly spaced from each electrode. Further, the amount of change in capacitance with respect to the solder feed amount is different from the usual amount. This is because the area of the solder facing the electrodes is different from that in the normal state, and the sensitivity to movement is different.

  In this way, the state of the solder can be detected based on the capacitance value.

  Next, an example of control in the automatic soldering apparatus 10 will be described with reference to FIG. When operating the automatic soldering apparatus 10, first, the target workpiece 11 is set on the automatic soldering apparatus 10 by the operator. Then, information regarding the soldering position for each target workpiece is input to the control PC 102. Thereafter, soldering is started. The automatic solder apparatus 10 is controlled by the control PC 102.

  First, in step S1, it is determined whether or not the soldering of all the parts inputted in advance is completed. When it is determined as Yes, the processing is ended (end).

  When it is determined No in step S1, the process proceeds to step S2. In step S2, the solder supply unit 13a is moved to the soldering position. In step S <b> 3, the supply of the solder 1 is started by the solder supply device 13. When the supply of the solder 1 is started, the solder state detection device 100 starts detecting the state of the solder 1 in step S4. That is, the abnormality shown in FIG. 9 is detected. As a result, in step S5, it is determined whether the solder amount is abnormal, that is, whether the tip of the solder 1 is spherical, too thick, or too thin is observed. When it is determined Yes in step S5, the process proceeds to step S6. In step S6, the control PC 102 issues an alarm by the alarm device 102a. The operator makes an adjustment, and presses the return switch 102b after the adjustment is completed. In step S7, it is determined whether or not the return switch 102b has been pressed. If it is determined YES in step S7, the processing from step S4 is repeated again. When it is determined No in step S5, the process proceeds to step S8. In step S8, it is determined whether or not an abnormality in the solder position, that is, a solder bend, has been detected. When it is determined Yes in step S8, the process proceeds to step S9. In step S9, the position and angle of the solder are adjusted by the moving stage 14. At this time, the control PC 102 calculates a deviation amount based on the value acquired from each capacitance bridge, and issues a movement command to the movement stage controller 14a. And when it is judged No at step S8, it progresses to step S10 and soldering is performed.

  As described above, according to the solder state detection apparatus 100 of the present embodiment, the state of the solder can be detected. That is, it is possible to detect even abnormalities of the shape such as clogging or bending of the solder 1 and being thick or thin. At this time, it is possible to detect the solder 1 without contact. Thereby, in the detection process, the tip shape of the solder is not affected.

  As shown in FIG. 11, the electrodes 201 a to 201 d may be arranged on the target work 111 instead of the electrodes 101 a to 101 d.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications, within the scope of the gist of the present invention described in the claims, It can be changed.

DESCRIPTION OF SYMBOLS 10 Automatic solder apparatus 11, 111 Target workpiece 12a-12d Electronic component 13 Solder supply apparatus 13a Solder supply part 13a1 Solder supply hole 13b Frame 14 Moving stage 14a Moving stage controller 15 Solder heating unit 100 Solder state detection apparatus 101a-101d, 201a- 201d electrode 102 control PC (arithmetic unit)
102a Alarm device 102b Return switch 103a to 103d Capacitance bridge 110 Equivalent circuit 111a to 111d Capacitor

Claims (2)

Electrodes disposed opposite to each other across a solder supply position where solder is supplied from a solder supply unit;
A capacitance value acquisition means for acquiring a capacitance value between the electrode and the solder supplied from the solder supply unit;
When the solder is normal, the balance of the capacitance value acquired for each electrode by the capacitance value acquisition means and the capacitance change amount that is the change amount of the capacitance value with respect to the solder feed amount. Based on the result of comparison with the amount of change in capacitance, a calculation unit that determines the bending of the solder supplied from the solder supply unit;
Solder bend detection device.   The solder bending detection device according to claim 1, wherein the electrodes are arranged at a center of gravity of a square at a solder supply position to which solder is supplied from a solder supply unit, and are arranged at four points of each vertex of the square.

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