JPS6211174A - Apparatus for inspecting soldering of electric parts - Google Patents

Abstract

PURPOSE:To rapidly and accurately inspect whether soldering is certainly performed, by providing a means for exerting magnetic force on the lead of electric parts soldered and a means for magnetically detecting displacement of said lead. CONSTITUTION:A detection probe 1 is controlled by a location control means and one terminal part 2a of a core 2 is allowed to approach the root part of a certain one iron lead 10 of the integrated circuit element 9 soldered to a printed circuit board 8. Further, a gap of a minute interval is provided between the relatively leading end part of the lead 10 and the printed circuit board 8 to locate the other terminal end part 2b of the core 2. Next, an AC signal successively changing in frequency is outputted from a sweep oscillator 6 to excite an exciting coil 3. As a result, the level signal corresponding to the change in magnetic flux is outputted from a detection coil 4 and detected by a detector 7. Inspection is performed by utilizing that the output of the detector becomes different by the quality of soldering.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the technical field of attaching electrical components to a circuit board by soldering, and in particular, it relates to the technical field of attaching electrical components to a circuit board by soldering. It relates to a device for inspecting whether or not the

[Conventional technology]

A circuit is formed by soldering various electronic or electrical components (herein, the term "electrical components" is used as a general term) including integrated circuit elements to a circuit board. In the manufacturing process, inspecting each electrical component after the circuit is formed to see if the soldering has been performed reliably is essential to guaranteeing the quality of the circuit. Conventionally, such inspection work was carried out by an operator visually checking the soldering of each electrical component lead for leakage or dislodgement.

[Problem that the invention seeks to solve]

However, the recent trend toward automation of soldering work and large-scale integration of electrical components has significantly increased the number of electrical components to be inspected, and has made visual inspection of electrical components itself extremely difficult. It has reached the point where it has been tightened. For this reason, the current state of the art is that the conventional inspection methods have reached their limits in both inspection efficiency and inspection accuracy.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a soldering inspection device that can perform an effective inspection in place of the conventional visual inspection.

[Means for solving problems]

The soldering inspection device for electrical components according to the present invention includes first means for applying a magnetic force to leads of soldered electrical components, and second means for magnetically detecting displacement of the leads. It is characterized by

[Operation] Leads of electrical components are generally made of iron, so soldering may leak or come off, and leads that are not securely soldered will be displaced due to the influence of magnetic force. On the other hand, leads that are securely soldered will not be displaced even under the influence of magnetic forces. Therefore, by magnetically detecting this displacement, it can be determined whether the leads are reliably soldered.

The first means for exerting a magnetic force on the lead includes a core having at least two ends and an excitation coil wound around the core, and the magnetic force is applied by bringing the end of the core close to the lead. Preferably, a magnetic circuit is formed through the core and the leads. Preferably, the second means for magnetically detecting the displacement of the lead includes a detection coil wound around the core. The following embodiments will be explained using these as examples.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a soldering inspection device according to the present invention. This testing device forms a magnetic circuit passing through the leads of an electrical component to be tested, and includes a detection probe 1 for detecting changes in magnetic flux in the magnetic circuit. The detection probe 1 is provided with a core 2 having two ends 2a and 2b, an excitation coil 6 and a detection coil wound around the core 2. The sweep oscillator 6 outputs an alternating current signal while changing the frequency kHL-order ratio between a predetermined maximum frequency and minimum frequency. The output signal of the detection coil 4 is given to the detector 7. The detector 7 detects the level of the output signal of the detection coil 4.

An example of inspection processing using this soldering inspection device is as follows.
It is as follows. By controlling the positioning of the detection probe 1 using a positioning control means (not shown), the second
As shown in the figure, one end 2a of the core 2 is placed close to or in contact with a relatively base portion of one iron glue 10 of an integrated circuit element 9 soldered to a printed circuit board 8. let Further, the lead 10 is positioned at the other end 2b' of the core 2, with a very small gap being provided between the lead 10 and the relatively leading end. As is well known, lead 1
The shape of 0 is not uniform. Therefore, in order to facilitate the setting of such a positional relationship between the cores 2a, 2b and the lead 10, the shape of the core 2 is suitably adjusted to match the shape of the lead 10, as illustrated in FIG. 2 or 3. It is preferable to change it.

Next, the sweep oscillator 6 outputs an AC signal whose frequency changes sequentially, and the excitation coil 3 is excited by this AC signal. As a result, a certain magnetic circuit is formed from the core 2, the lead 10, and the air gap, and a magnetic flux whose direction and magnitude change over time passes through this magnetic circuit.

As a result, the detection coil 4 outputs a signal with a level corresponding to this change in magnetic flux, and this output signal is detected by the detector 7.

Here, if the soldering of the lead 10 is leaking or coming off, the lead 10 should be connected to the end 2b of the core 2.
Under the influence of magnetic flux (that is, lines of magnetic force) penetrating the air gap between 0 and 0, minute vibrations start in response to changes in the direction and magnitude of the lines of magnetic force.

Furthermore, in the process in which the period of change in the magnetic field lines changes in accordance with the change in the frequency of the output AC signal of the sweep oscillator 6, if this period matches the unique mechanical resonance frequency of the reed 10, at that moment The amplitude of this vibration becomes even larger. As a result, the end 2a of the core 2 and the lead 10
Since the distance between the air gaps changes over time, the magnetic resistance of the magnetic circuit changes over time.

Therefore, in this case, the magnetic flux of the magnetic circuit changes not only due to the temporal change in the output signal of the sweep oscillator 6 but also due to the temporal change in magnetic resistance, so the output level of the detection coil 4 changes. , this change in output level is detected by the detector 7.

On the other hand, if the leads 10 are reliably soldered to the printed circuit board 8, the leads 10 will not be displaced even under the influence of these lines of magnetic force. Therefore, in this case, the output level of the detection coil 4 does not change, and this change is not detected by the detector 7.

In this way, the detection results of the detector 7 are different depending on whether the leads 10 are reliably soldered or not. Thereby, it is possible to accurately confirm whether or not the leads 10 are reliably soldered based on the detection results of the detector 7.

When the quality of the soldering with respect to the lead 16 is confirmed as described above, the position of the detection probe 1 is changed using the positioning control means (not shown), and the position of the detection probe 1 is changed to the other soldering lead 10 of the integrated circuit element 9. Execute similar processing for

By sequentially performing the same process on each lead 10 of the integrated circuit element 9, it is possible to accurately inspect whether or not the entire integrated circuit element 9 is reliably soldered. .

By the way, as is well known, the integrated circuit element 9 is generally provided with a large number of glues 10 as illustrated in FIG. 4. Therefore, in order to carry out more efficient inspection processing for such integrated circuit elements, it is sufficient to configure an inspection apparatus as shown in FIG. 5, which is provided with a plurality of detection probes 1.

In the figure, a detection head 11 has a plurality of detection probes 1 arranged as shown in FIG. 1 in accordance with the number of leads and the distance between each lead in an integrated circuit element to be tested. The excitation coil of each probe 1 has a first
The output signal of the sweep oscillator 6 is applied via the driver 5 as shown in the figure. Sweep oscillator 6 is controlled by processing section 12 . On the other hand, all output signals of the detection coils of each probe 1 are given to the switch 13.

The switch 13 selectively outputs one of the input signals, and this selected output signal is applied to the same detector 7 as shown in FIG.

A signal indicating the detection result of the detector 7 is given to the processing section 12 .

When performing an inspection process using this inspection device, positioning control means of the detection head 11 is controlled using a positioning control means (not shown), thereby aligning the core of each detection probe 1 with each lead of the integrated circuit element to be inspected. All of them are made to correspond one-to-one in a positional relationship as shown in FIG. 2 (or FIG. 3). Then, with the excitation coil of each detection probe 1 excited by the output signal of the sweep oscillator 6, the output signal of the detection coil of each detection probe 1 is sequentially and selectively applied to the detector 7 by the switch 16, and the detection result is The processing unit 13
Process at. As a result, it is possible to accurately and more efficiently test whether or not the entire integrated circuit element to be tested is reliably soldered.

In the above embodiment, the excitation coil of the detection probe is excited by the output AC signal of the sweep oscillator, but the invention is not limited to this, and the excitation coil may be excited by an AC signal having a constant frequency. good. In this case, it is desirable to match the frequency with the mechanical resonance frequency of the reed to be inspected in order to improve inspection accuracy. However, if the output AC signal of the sweep oscillator is used for excitation as in the embodiment, even if the mechanical resonance frequency of the lead to be inspected is unknown,
There is an advantage that the vibration period of the reed can be matched to its mechanical resonance frequency.

Further, in this embodiment, the excitation coil is excited by an AC signal, but the present invention is not limited to this, and the excitation coil may be excited by a DC signal.

In this case, a magnetic flux that does not change over time passes through the magnetic circuit, and a magnetic force that does not change over time is applied to the lead that is being tested. The detection probe is drawn toward the end of the core, and the distance between the IJ-de and the end of the core becomes narrow. As a result, in a magnetic circuit that includes leads that leak or come loose during soldering, the magnetic flux changes (increases) and a signal is output from the detection coil, so it can still be detected whether the leads are reliably soldered. This means that confirmation can be made based on the detection results of the device.

〔Effect of the invention〕

As described above, according to the soldering inspection device for electrical components according to the present invention, by magnetically detecting the displacement of the leads of the electrical components due to the influence of magnetic force, it is possible to check whether the electrical components are reliably soldered. It is possible to quickly and easily and accurately test whether or not the Therefore, the present invention has the excellent effect of being able to perform efficient and accurate inspections while fully responding to the trends of automation of soldering work and large-scale integration of electrical components.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the soldering inspection device according to the present invention, and FIGS. 2 and 3 show examples of changes in the shape of the core in the soldering inspection device of FIG. Figure 4 shows the positional relationship with the lead.
FIG. 5 is a perspective view showing an example of an electrical component inspected by the soldering inspection apparatus shown in the figure, and FIG. 5 is a circuit block diagram showing a modification of the soldering inspection apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1...Detection probe, 2...Core, 2a, 2
b"' end, 3... Excitation coil, 4... Detection coil, 5... Driver, 6... Sweep oscillator, 7...
...Detector, 8... Printed circuit board, 9... Integrated circuit element, 10... Lead, 11... Detection head, 12
...processing section, 16...switching device. Applicant Hitachi Electronics Engineering Co., Ltd. Agent
Yoshihito Iizuka Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. The device is characterized by comprising a first means for exerting a magnetic force on the leads of the soldered electrical components, and a second means for magnetically detecting displacement of the leads. Soldering inspection equipment for electrical parts. 2. The first means includes a core having at least two ends and an excitation coil wound around the core, and by bringing the ends of the core close to the lead, the core and the lead are connected. 2. The soldering inspection apparatus for electrical components according to claim 1, wherein the second means includes a detection coil wound around the core. 3. The electric component solder according to claim 2, wherein the exciting coil is excited by a sweep oscillator that outputs an alternating current signal while sequentially changing the frequency between a certain maximum frequency and a certain minimum frequency. Inspection equipment included.