Circuit board and BGA welding spot pseudo soldering infrared detector

Abstract

The utility model discloses a circuit board and BGA welding spot pseudo soldering infrared detector, and belongs to the technical field of printed circuit board welding spot quality off-line detection. The infrared thermal imager A and the circuit board to be tested are arranged above the partition plate perspective hole up and down, the laser spot shaping controller A is arranged below the partition plate perspective hole, the infrared thermal imager A is installed on the partition plate through the thermal imager support, and the circuit board to be tested is placed on the hollow X-Y electric sliding table. The laser spot shaping controller A is mounted on a bottom plate of the cabinet through an electric lifting sliding table, and the laser spot shaping controller A is connected with the fiber laser B. According to the utility model, a laser heating mode and an infrared thermal imager thermal imaging mode are adopted for welding spot detection, so that pseudo welding spots can be effectively detected. The device is mainly used for detecting the pseudo soldering of the BGA chip welding spots on a circuit board, and also can detect the pseudo soldering of the welding spots of other surface-mounted components. And the quality detection of various welding spots on the circuit board can be basically realized by one machine on hand.

Description

TECHNICAL FIELD

[0001] The utility model belongs to printed circuit board solder joint quality off-line detection technical field, specifically relates to a kind of detection instrument that can realize the detection of various solder joint defects including BGA chip solder joint on circuit board. BACKGROUND

[0002] Solder joint false soldering is a common problem in the production process of printed circuit board, and existing detection technologies, such as automatic optical detection (AOI), automatic X-ray detection (AXI) and temperature shock test, cannot effectively detect such defects of solder joint, often leading to early failure of products in service period, causing immeasurable economic losses and social impact to users.

[0003] Automatic optical detection (AOI) technology is to capture images of components on a circuit board by a CCD camera, and to compare the images with images of qualified circuit boards in a database by software, which can mainly detect open circuit, solder bridge, insufficient solder, excessive solder and other appearance problems of solder joint, but cannot detect internal defects or false soldering of solder joint.

[0004] AXI (automatic X-ray detection) technology is to detect the quality of solder joints on a circuit board by X-ray perspective function, which can possibly show the existence of large pores or inclusions in solder joint by X-ray images, but cannot detect false soldering, cracks and cold soldering.

[0005] BGA chips are widely used due to their irreplaceable advantages, but the quality detection of solder joints hidden between the chip and the circuit board has become the most painful problem in the current electronic industry. Even if a manufacturer has a 3D-5D AXI worth millions of dollars, it can only be used to count pores in the solder joint, and cannot determine whether there is false soldering (X-ray is suitable for detecting volume defects such as pores, but is powerless for two-dimensional defects such as cracks and false soldering).

[0006] There is an urgent need for a technology and equipment that can reliably and effectively detect various false soldering in the production process and maintenance field of the electronic industry. The utility model is born under this demand background, and has a wide range of application scenarios. CONTENT OF THE UTILITY MODEL

[0007] The utility model is to solve the above problems, and further provides a circuit board and BGA solder joint false soldering infrared detector, which can detect the quality of various solder joints on a circuit board.

[0008] The technical solution adopted by the utility model is as follows:

[0009] A kind of circuit board and BGA weld point false weld infrared detector, including cabinet, infrared thermal imager A, X-Y electric sliding table, electric lifting sliding table, laser spot shaping controller, fiber laser B, display and operation console;The perspective hole is opened in the partition of the cabinet, the infrared thermal imager A and the to-be-measured circuit board are arranged above the perspective hole of partition, the laser spot shaping controller A is arranged below the perspective hole of partition, the infrared thermal imager A is installed on the partition by thermal imager support, to-be-measured circuit board is placed on hollow X-Y electric sliding table, the laser spot shaping controller A is installed on the bottom plate of cabinet by electric lifting sliding table, the laser spot shaping controller A is connected with fiber laser B, display and operation console are installed on the outside of the cabinet, the infrared thermal imager A is connected with display, the operation console is connected with fiber laser B, X-Y electric sliding table and electric lifting sliding table.

[0010] Compared with prior art, the utility model has the following beneficial effects:

[0011] The utility model discloses a laser heating and infrared thermal imager thermography mode are carried out to the weld point detection, can effectively detect false weld weld point, and the utility model discloses a controllable opening and closing grating mechanism can effectively control the size and the length-width ratio of output rectangular spot, make it irradiate on the surface of to-be-measured chip, and do not irradiate on the circuit board, avoid causing damage to the circuit board.

[0012] The utility model mainly aims at the detection of false weld of BGA chip weld point on circuit board, and also considers the false weld detection of other mounted component weld points. ACCURACY

[0013] Figure 1 It is the axonometric drawing of the utility model;

[0014] Figure 2 It is the structure schematic view of the utility model;

[0015] Figure 3 It is the schematic view of laser spot shaping controller of the utility model;

[0016] Figure 4 It is the axonometric drawing of laser spot shaping controller of the utility model;

[0017] Figure 5 It is the structure schematic view of controllable opening and closing grating mechanism of the utility model;

[0018] Figure 6 It is the installation schematic view of sliding support of the utility model;

[0019] Wherein: 1, cabinet; 2, partition; 3, thermal imager support; 4, infrared thermal imager A; 5, to be measured circuit board; 6, X-Y electric sliding table; 7, electric lifting sliding table; 8, laser spot shaping controller A; 9, fiber laser A; 10, fiber laser B; 11, detector electric control box; 12, display; 13, operation console; 14, PLC programmable controller; 15, electric heating film adjustable power supply; 16, electric heating film pulse controller; 17, electric heating film socket; 18, laser spot shaping controller B; 19, infrared thermal imager B; 20, BGA chip; 201, perspective hole; 601, sliding rail; 602, sliding support; 603, connecting shaft; 801, controllable opening and closing grating mechanism; 802, beam expander; 803, laser head; 804, switch door; 805, guide rail; 806, driving device; 807, connecting plate. DETAILED DESCRIPTION

[0020] In order to better understand the purpose, structure and function of the utility model, the utility model will be described in further detail below with reference to the drawings.

[0021] The virtual welding spot in the utility model is a general term, which includes various welding spot defects such as welding spot crack, cold welding and blowhole.

[0022] As shown in Figure 1 , Figure 2 The utility model provides a kind of circuit board and BGA virtual welding infrared detector, including cabinet 1, infrared thermal imager A 4, X-Y electric sliding table 6, electric lifting sliding table 7, laser spot shaping controller A 8, fiber laser B 10, display 12 and operation console 13;The perspective hole 201 is opened on the partition 2 of the cabinet 1, and the infrared thermal imager A 4 and the to-be-measured circuit board 5 are arranged above the perspective hole 201 of the partition 2, the laser spot shaping controller A 8 is arranged below the perspective hole 201 of the partition 2, the infrared thermal imager A 4 is installed on the partition 2 by thermal imager support 3, the to-be-measured circuit board 5 is placed on hollow X-Y electric sliding table 6, the laser spot shaping controller A 8 is installed on the bottom plate of cabinet 1 by electric lifting sliding table 7, the laser spot shaping controller A 8 is connected with fiber laser B 10, display 12 and operation console 13 are installed on the outside of the cabinet 1, the infrared thermal imager A 4 is connected with display 12, and display 12 can display corresponding infrared thermal image;The operation console 13 is connected with fiber laser B 10, X-Y electric sliding table 6 and electric lifting sliding table 7.

[0023] The cabinet 1 is built-in detector electric control box 11, and is connected with operation console 13, fiber laser B 10, X-Y electric sliding table 6 and electric lifting sliding table 7.

[0024] Thermal imager support 3 can use electric lifting slide or manual screw lifting mechanism.

[0025] Infrared thermal imager A4 is connected with thermal imager support 3 through an adjustable connector.

[0026] The adjustable connector can use existing installation components.

[0027] As shown in Figure 3~Figure 5 The laser spot shaping controller A8 comprises, from bottom to top, a laser head 803, an expansion lens 802 and a controllable opening and closing grating mechanism 801 arranged in the shell in sequence; the laser head 803 is connected with the fiber laser B10.

[0028] The controllable opening and closing grating mechanism 801 comprises two groups of opening and closing devices; each group of opening and closing devices comprises two switch doors 804, two guide rails 805 and two driving devices 806.

[0029] The two switch doors 804 are oppositely arranged, the two guide rails 805 are fixed in the shell and arranged in parallel outside the two switch doors 804, each switch door 804 is slidably connected with the two guide rails 805 at both ends, the two driving devices 806 are symmetrically arranged at both sides of the switch door 804, each driving device 806 is connected with one switch door 804 to control the linear movement of the switch door 804, and the two driving devices 806 are fixed on the shell.

[0030] The two groups of opening and closing devices are arranged horizontally and crosswise, so that the four switch doors 804 form an adjustable opening and closing port in the shape of a rectangle.

[0031] The driving device 806 can be a micro motor or a micro electric telescopic rod.

[0032] When the driving device 806 is a micro motor, the output shaft of the micro motor is connected with a screw rod, the screw rod is threadedly connected with a screw hole of a connecting plate 807, the connecting plate 807 is fixedly connected with the corresponding switch door 804, and the micro motor drives the connecting plate 807 to move linearly through the screw rod, so as to drive the switch door 804 to move.

[0033] When the driving device 806 is a micro electric telescopic rod, the telescopic end of the micro electric telescopic rod is connected with the corresponding switch door 804 through the connecting plate 807.

[0034] As shown in Figure 6As shown in the figure, a hollow mouth of the X-Y electric sliding table 6 platform is provided with a sliding rail 601 on each side, and the two sliding rails 601 are arranged in parallel. The hollow mouth of the X-Y electric sliding table 6 platform is provided with two sliding supports 602, and the two ends of the two sliding supports 602 are connected with the two sliding rails 601 through connecting shafts 603. The two sliding supports 602 are used for clamping the circuit board 5 to be measured.

[0035] As shown in the figure, Figure 1 , Figure 2 As shown in the figure, the circuit board and BGA solder joint false welding infrared detector further comprises an infrared thermal imager B19, which is arranged below the partition plate 2. The infrared thermal imager B19 is obliquely installed on the guide rail of the electric lifting sliding table 7 and faces the laser spot shaping controller A8 without blocking the laser beam. The field of view can observe the inverted circuit board BGA chip to be measured above. The infrared thermal imager B19 is connected with the display 12.

[0036] The infrared thermal imager A4 is a main detector with high technical parameters and price;

[0037] The infrared thermal imager B19 has lower technical parameters and price, and only serves as an auxiliary observation of laser spot positioning. Because the infrared waveband laser used in the machine has low visibility, it is difficult to observe the size and position of the irradiated laser spot visually, so the infrared thermal imager B19 is used for auxiliary observation.

[0038] As shown in the figure, Figure 1 , Figure 2 As shown in the figure, the circuit board and BGA solder joint false welding infrared detector further comprises a laser spot shaping controller B18, which has the same structure as the laser spot shaping controller A8. The laser spot shaping controller B18 is installed on the thermal imager support 3, and the laser spot shaping controller B18 is connected with the fiber laser A9.

[0039] The fiber laser A9 and the fiber laser B10 are both high-power infrared lasers. The fiber laser A9 and the fiber laser B10 are both arranged below the partition plate 2 of the cabinet 1. The fiber of the fiber laser A9 passes through the partition plate 2 and is connected with the laser spot shaping controller B18.

[0040] As shown in the figure, Figure 1 , Figure 2As shown, the operation console 13 includes a PLC programmable controller 14; the PLC programmable controller 14 is connected with the fiber laser A9 and the fiber laser B10, and can set and control the power and pulse width time parameters thereof respectively; the PLC programmable controller 14 is connected with the X-Y electric sliding table 6 and the electric lifting sliding table 7, and can control the X-Y direction and vertical direction movement thereof respectively; the PLC programmable controller 14 is connected with the laser spot shaping controller A8 and the laser spot shaping controller B18, and can control the opening and closing of the two groups of grating opening and closing devices respectively.

[0041] As shown in Figure 1 , Figure 2 As shown, the circuit board and BGA solder joint virtual welding infrared detector further includes an electrothermal film loading system;

[0042] The electrothermal film loading system includes an electrothermal film, an electrothermal film adjustable power supply 15, an electrothermal film pulse controller 16 and an electrothermal film socket 17; the electrothermal film is attached to the circuit board 5 to be tested, the electrothermal film adjustable power supply 15, the electrothermal film pulse controller 16 and the electrothermal film socket 17 are arranged on the operation console 13, the electrothermal film can be connected with the electrothermal film socket 17, the electrothermal film socket 17 is connected with the electrothermal film pulse controller 16, and the electrothermal film pulse controller 16 is connected with the electrothermal film adjustable power supply 15.

[0043] The lens axis of the infrared thermal imager A4 coincides with the center axis of the laser beam emitted from the laser spot shaping controller A8 from below.

[0044] The detection step

[0045] I. BGA chip solder joint detection:

[0046] 1. When detecting BGA type solder joints, the circuit board 5 to be tested is inverted and fixed on the X-Y electric sliding table 6 and the sliding support 602, and the BGA chip 20 to be tested on the circuit board 5 to be tested is punched down;

[0047] 2. The X-Y electric sliding table 6 is controlled to move on the operation console 13 through the PLC programmable controller 14, so that the BGA chip to be tested is located on the center line of the field of view of the infrared thermal imager A4 lens;

[0048] 3. Start the fiber laser B10, and set the test laser parameters (both the laser power and the pulse width time are small);

[0049] 4. The infrared thermal imager B19, which uses laser spot-assisted positioning on the display 12, monitors the interface image. On the operation control console 13, the PLC programmable controller 14 controls the grating to output a rectangular spot to illuminate the surface of the BGA chip 20 under test. The entire surface can be illuminated as needed, or only a part of the chip (such as an edge or a corner, which can obtain a relatively higher contrast of solder joint defects) can be illuminated. At the same time, the circuit board 5 under test is not illuminated (on the one hand, it may cause damage to the surface of the circuit board 5 under test, and on the other hand, the laser illuminating the circuit board 5 under test will interfere with the test results).

[0050] 5. The electric lifting slide 7 can be controlled by the PLC programmable controller 14 to drive the laser spot shaping controller A8 to move up and down, thereby obtaining a spot of appropriate size (the spot becomes smaller when moving upward and larger when moving downward).

[0051] 6. Set the detection laser parameters. Generally, the temperature at the via of the BGA chip under test should rise from room temperature by 10-50 degrees Celsius within 1-5 seconds, while ensuring that the chip surface is not thermally damaged.

[0052] 7. First, start the A4 recording function of the infrared thermal imager, then start the fiber laser B10 to output the laser with the above-set parameters. After the laser stops outputting, turn off the A4 recording function of the infrared thermal imager.

[0053] 8. Review the A4 inspection video recording from the infrared thermal imager.

[0054] 9. Select the frame with the largest temperature difference between the via point and the surrounding green solder mask as the result thermal image. Compare this thermal image with the standard thermal image of a qualified chip obtained under the same parameters. Abnormally low temperature points can be identified as cold solder joints.

[0055] 10. There are many types of BGA chips. When encountering chips with metal caps, due to their high reflectivity and poor laser heat loading effect, it is necessary to use the electrothermal film heat loading mode or the following methods for testing.

[0056] II. Inspection of Special BGA Chips and Other Surface Mount Solder Joints:

[0057] 1. The inspection of other special BGA chip solder joints (ultra-large and ultra-thick size) and surface mount solder joints mainly relies on fiber laser A9 or electrothermal film heat loading system as heat loading source.

[0058] 2. This method can be used for special BGA chip solder joints (extra-large and extra-thick sizes, when the above method is ineffective). That is, the circuit board is also facing down, and the via position of the BGA chip solder joint to be tested on the control circuit board is located directly below the laser spot shaping controller B18.

[0059] 3, adjust the infrared thermal imager A4 to an appropriate angle, so that the through-hole area of the component to be tested is located at the center of the field of view;

[0060] 4, start the fiber laser A9, and set the test laser parameters (both the laser power and the pulse width time are small);

[0061] 5, monitor the image on the display 12 through the infrared thermal imager A4 interface, and control the grating to output a light spot on the surface of the through-hole area of the component to be tested through the PLC programmable controller 14 on the operation console 13; at the same time, no light spot is irradiated on the circuit board;

[0062] 6, set the detection laser parameters, which generally make the surface of the component to be tested rise by 10-50 degrees Celsius in 1-5 seconds from room temperature and ensure that the surface of the component to be tested and the green oil on the board do not cause thermal damage;

[0063] 7, start the fiber laser A9, and when it stops working, automatically or manually start the infrared thermal imager A4 to take a thermal image;

[0064] 8, compare the thermal image with the standard sample thermal image, and the abnormally high temperature point is the false soldering point (when there is no standard sample, the specific situation of the lead of the component soldering point should be analyzed and judged).

[0065] 9, when detecting other mounted soldering points, the front of the circuit board is upward (i.e. the component to be tested faces upward) and is fixed on the sliding bracket 602 of the X-Y electric sliding table 6;

[0066] 10, when using the electrothermal film heat loading mode, first, an appropriate electrothermal film is pasted on the surface of the component to be tested, the electrothermal film wire is inserted into the electrothermal film socket 17, and appropriate heat loading parameters are set through the electrothermal film adjustable power supply 15 and the electrothermal film pulse controller 16;

[0067] 11, control the circuit board to move the X-Y electric sliding table 6 through the PLC programmable controller 14 on the operation console 13, so that the component to be tested is located on the center line of the lens field of view of the infrared thermal imager A4;

[0068] 12, start the electrothermal film heat loading;

[0069] 13, after the electrothermal film heat loading is completed, automatically or manually start the infrared thermal imager A4 to take a thermal image;

[0070] 14, compare the thermal image with the standard sample thermal image, and the abnormally high temperature point is the false soldering point (when there is no standard sample, the specific situation of the lead of the component soldering point should be analyzed and judged);

[0071] 15. When using laser heat loading mode for testing, the circuit board must also be facing upwards (i.e., the component to be tested is fixed on the sliding bracket 602 of the XY electric slide table 6 with the component facing upwards).

[0072] 16. On the operation control console 13, the PLC programmable controller 14 controls the movement of the circuit board XY electric slide table 6 so that the component under test is located directly below the laser spot shaping controller B18.

[0073] 17. Adjust the infrared thermal imager A4 to a suitable angle so that the component under test is located in the center of its field of view;

[0074] 18. Start the fiber laser A9 and set the test laser parameters (both laser power and pulse width time are relatively low).

[0075] 19. Monitor the interface image using the infrared thermal imager A4 on the display 12, and control the grating on the operation control console 13 via the PLC programmable controller 14 to make its output light spot illuminate the surface of the component under test; at the same time, it does not illuminate the circuit board.

[0076] 20. Set the detection laser parameters. Generally, the surface temperature of the component under test should rise from room temperature by 10-50 degrees Celsius within 1-5 seconds, while ensuring that the surface of the component will not suffer thermal damage.

[0077] 21. Start the fiber laser A9. When it stops working, automatically or manually start the infrared thermal imager A to take a picture of the thermal image.

[0078] 22. Compare the thermal image with the standard sample thermal image. Abnormally high temperature points are poor solder joints (if there is no standard sample, the specific situation of the solder joint leads of the component should be analyzed and judged).

[0079] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this utility model.

Claims

1. An infrared detector for detecting cold solder joints on circuit boards and BGAs, characterized in that: The utility model relates to a kind of laser spot shaping control device, including cabinet (1), infrared thermal imager A (4), X-Y electric sliding table (6), electric lifting sliding table (7), laser spot shaping controller A (8), fiber laser B (10), display (12) and operation console (13);Perspective hole (201) is opened in the partition (2) of cabinet (1), infrared thermal imager A (4) and measured circuit board (5) are arranged above the perspective hole (201) of partition (2), laser spot shaping controller A (8) is arranged below the perspective hole (201) of partition (2), infrared thermal imager A (4) is installed on partition (2) by thermal imager support (3), measured circuit board (5) is placed on hollow X-Y electric sliding table (6), laser spot shaping controller A (8) is installed on the bottom plate of cabinet (1) by electric lifting sliding table (7), laser spot shaping controller A (8) is connected with fiber laser B (10), display (12) and operation console (13) are installed outside cabinet (1), infrared thermal imager A (4) is connected with display (12), operation console (13) is connected with fiber laser B (10), X-Y electric sliding table (6) and electric lifting sliding table (7).

2. The circuit board and BGA solder joint false solder infrared detector according to claim 1, characterized in that: The laser spot shaping controller A (8) includes a laser head (803), a beam expander lens (802), and a controllable opening and closing grating mechanism (801) arranged in the housing from bottom to top.

3. The circuit board and BGA solder joint false solder infrared detector according to claim 2, characterized in that: The controllable opening and closing grating mechanism (801) includes two sets of opening and closing devices. Each set of opening and closing devices includes two switch doors (804), two guide rails (805), and two drive devices (806). The two switch doors (804) are oppositely arranged, the two guide rails (805) are parallelly arranged outside the two switch doors (804) and fixed in the housing, each switch door (804) is slidably connected to the two guide rails (805) at both ends, the two drive devices (806) are symmetrically arranged at both sides of the switch door (804), and each drive device (806) is connected to one switch door (804) to control the linear motion of the switch door (804).

4. The circuit board and BGA solder joint false solder infrared detector according to claim 1, characterized in that: The two sets of opening and closing devices are horizontally arranged above and below, and the two sets of opening and closing devices are cross-shaped, so that the four switch doors (804) form an adjustable opening and closing port in the shape of a rectangle. Two slide rails (601) are arranged on both sides of the hollow opening of the X-Y electric sliding table (6) platform, the two slide rails (601) are parallelly arranged, two slide supports (602) are arranged on the hollow opening of the X-Y electric sliding table (6) platform, the two ends of the two slide supports (602) are slidably connected to the two slide rails (601) through connecting shafts (603), and the two slide supports (602) are used for clamping the measured circuit board (5).

5. The circuit board and BGA solder joint cold solder infrared detector of claim 1, wherein: The circuit board and BGA solder joint false welding infrared detector further comprises an infrared thermal imager B (19), the infrared thermal imager B (19) is arranged below the partition (2), the infrared thermal imager B (19) is obliquely installed on the guide rail of the electric lifting slide (7), and is directed to the laser spot shaping controller A (8), and the infrared thermal imager B (19) is connected with the display (12).

6. The circuit board and BGA solder joint cold solder infrared detector of claim 5, wherein: The circuit board and BGA solder joint false welding infrared detector further comprises a laser spot shaping controller B (18), the structure of the laser spot shaping controller B (18) is same as that of the laser spot shaping controller A (8), the laser spot shaping controller B (18) is installed on the thermal imager support (3), and the laser spot shaping controller B (18) is connected with the fiber laser A (9).

7. The circuit board and BGA solder joint cold solder infrared detector of claim 6, wherein: The operation console (13) comprises a PLC programmable controller (14); the PLC programmable controller (14) is connected with the fiber laser A (9) and the fiber laser B (10), the PLC programmable controller (14) is connected with the X-Y electric slide (6) and the electric lifting slide (7), and the PLC programmable controller (14) is connected with the laser spot shaping controller A (8) and the laser spot shaping controller B (18).

8. The circuit board and BGA solder joint cold solder infrared detector of claim 7, wherein: The circuit board and BGA solder joint false welding infrared detector further comprises an electric heating film loading system. The electric heating film loading system comprises an electric heating film, an electric heating film adjustable power supply (15), an electric heating film pulse controller (16) and an electric heating film socket (17); the electric heating film is attached to the circuit board (5) to be measured, the electric heating film adjustable power supply (15), the electric heating film pulse controller (16) and the electric heating film socket (17) are arranged on the operation console (13), the electric heating film can be connected with the electric heating film socket (17), the electric heating film socket (17) is connected with the electric heating film pulse controller (16), and the electric heating film pulse controller (16) is connected with the electric heating film adjustable power supply (15).

9. The circuit board and BGA solder joint cold solder infrared detector of claim 1, wherein: The lens axis of the infrared thermal imager A (4) coincides with the central axis of the laser beam emitted from the laser spot shaping controller A (8) below.

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