An aoi test tool for appearance inspection of workpieces
By improving the structure and technical means of AOI testing fixtures, the problems of insufficient detection accuracy and poor adaptability of existing AOI testing fixtures have been solved, enabling efficient and low-cost multi-variety production and inspection of irregularly shaped PCBs.
Patent Information
- Application Number
- CN202521843790.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-28
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-08-28
AI Technical Summary
Existing AOI testing fixtures suffer from problems such as insufficient precision in microelectronics testing, large errors in traditional mechanical positioning, high rate of missed detection of solder joint defects, poor adaptability to multi-variety production, high frequency of line changes, high cost, and difficulty in testing irregularly shaped PCBs.
It employs components such as carbon fiber substrate, detachable positioning module, light shield module, magnetic quick-change interface and partitioned vacuum adsorption array, combined with air flotation non-contact positioning, optical multi-dimensional imaging and dynamic closed-loop compensation technology to achieve intelligent adsorption fixation and high-precision detection.
It improves detection accuracy, reduces mechanical deformation and false negative rate, enhances adaptability to multi-variety production, reduces changeover time and cost, and meets the detection needs of irregularly shaped PCBs.
Smart Images
Figure CN224682120U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of inspection tool technology, specifically an AOI testing fixture for workpiece appearance inspection. Background Technology
[0002] AOI testing, or Automated Optical Inspection, is a testing technology based on optical principles used to detect common defects encountered on PCBs during soldering production. Test fixtures are an important component of automated optical inspection equipment, used to fix and support the object under test during the testing process, ensuring the accuracy and stability of the test. In general, AOI test fixtures are an indispensable part of automated optical inspection equipment, playing a crucial role in ensuring the accuracy and stability of the test.
[0003] Existing technologies suffer from insufficient precision in microelectronics testing, large positioning errors in traditional mechanical systems, solder joint defects, a false negative rate of >35% in existing optical systems, poor adaptability to multi-variety production, high frequency of line changes in 3C electronics, long time consumption for changing traditional tooling, high cost for custom tooling for irregularly shaped PCBs (such as foldable screen FPCs), and difficulty in testing highly reflective / flexible components. Utility Model Content
[0004] The purpose of this invention is to provide an AOI testing fixture for workpiece appearance inspection, so as to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, this utility model provides the following technical solution:
[0006] An AOI testing fixture for workpiece appearance inspection includes:
[0007] Carbon fiber substrate: The surface is sandblasted and matte, with a light-transmitting hole in the center. Multiple air-floating nozzles are evenly distributed around the outer ring of the hole, and the nozzle axis is inclined towards the center of the light-transmitting hole.
[0008] Detachable positioning module: Symmetrically fixed on both sides of the carbon fiber substrate, the detachable positioning module integrates: ceramic positioning pins with built-in optical fiber light guide channels, the output direction of the detachable positioning module is tilted to the horizontal plane; and an air-bearing support unit with air pressure sensor and piezoelectric ceramic fine adjustment column.
[0009] Light shield module: Covering the carbon fiber substrate, the side wall of the light shield module has a light-transmitting slit with an angle matching the field of view of the AOI lens;
[0010] Magnetic quick-change interface: located at the assembly interface between the positioning module and the carbon fiber substrate, including the magnetic ring and RFID chip inside the substrate;
[0011] Partitioned vacuum adsorption array: Silicone suction cups cover the central area of the carbon fiber substrate and are distributed around the light-transmitting holes.
[0012] As a further embodiment of this utility model:
[0013] The air pressure data of the air-bearing support unit drives the height compensation of the piezoelectric fine-tuning column; the output light of the optical fiber light guide channel is misaligned with the spectral band of the coaxial light source.
[0014] As a further embodiment of this utility model:
[0015] Below the light-transmitting hole is a downward-viewing lens module containing a liquid lens; the inner wall of the light-transmitting hole is coated with an anti-reflection film.
[0016] As a further embodiment of this utility model:
[0017] The bottom of the light shield module is slidably engaged with the dovetail groove on the side of the substrate via a snap fastener; the positioning module is fitted to the substrate via a tapered guide post and an elastic sleeve.
[0018] As a further embodiment of this utility model:
[0019] The adsorption force of the partitioned vacuum adsorption array is adaptively adjusted according to the product thickness; the RFID chip controls the partition activation of the adsorption array.
[0020] As a further embodiment of this utility model:
[0021] An anti-reflective microprism film is attached to the inner wall of the light-transmitting slit; a buffer spring is provided at the bottom of the positioning module.
[0022] As a further embodiment of this utility model:
[0023] The air flotation nozzles are distributed in a ring around the light-transmitting hole, and the airflow direction is inclined to the axis of the light-transmitting hole.
[0024] Compared with the prior art, the beneficial effects of this utility model are:
[0025] This utility model achieves: 1. Air-float non-contact positioning: the air-float nozzle sprays inclined airflow to form a uniform air film to support the product; the air pressure sensor monitors the pressure in real time and the piezoelectric ceramic fine-tuning column compensates for the height, which solves the problem of product deformation caused by traditional mechanical clamping.
[0026] 2. Optical multi-dimensional imaging: Coaxial light source 107 red light vertical illumination to capture surface solder joint defects; Fiber optic light guide pin: Infrared light 45° side supplementary lighting to penetrate solder paste and detect underlying cold solder joints; Liquid lens: Millisecond-level zoom to be compatible with products with a thickness of 0.1-5mm, solving the shadow blind spots existing in traditional single light source.
[0027] 3. Dynamic closed-loop compensation: The downward-looking lens calculates the position deviation by shooting the positioning pin through the light-transmitting hole 501, and the piezoelectric ceramic compensates in real time, which solves the problem of low efficiency of manual adjustment.
[0028] 4. Intelligent adsorption and fixation: RFID reads the product outline and activates only the suction cups within the outline, solving the problem of damage to flexible parts caused by negative pressure throughout the entire area. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the vertical plane of the carbon fiber substrate of this utility model.
[0030] Figure 2 This is a side view of the present invention.
[0031] In the diagram: 101, carbon fiber substrate; 102, positioning module; 103, partitioned vacuum adsorption array; 104, magnetic quick-change interface; 105, light shield module; 201, air pressure sensor; 202, piezoelectric ceramic fine-tuning column; 301, fiber optic light guide channel; 401, light-transmitting slit; 501, light-transmitting hole; 502, downward-viewing lens module. Detailed Implementation
[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0033] Please see Figures 1 to 2 In this embodiment of the present invention, an AOI testing fixture for workpiece appearance inspection includes:
[0034] Carbon fiber substrate 101: The surface is sandblasted and matte, and a light-transmitting hole 501 is opened in the center. Multiple air-floating nozzles are evenly distributed around the outer ring of the hole, and the axis of the nozzles is inclined towards the center of the light-transmitting hole.
[0035] Detachable positioning module 102: Symmetrically fixed on both sides of carbon fiber substrate 101, the detachable positioning module 102 integrates: ceramic positioning pin with built-in optical fiber light guide channel 301, the output direction of the detachable positioning module 102 is inclined to the horizontal plane; air-bearing support unit with air pressure sensor 201 and piezoelectric ceramic fine adjustment column 202.
[0036] Light shield module 105: Covers the carbon fiber substrate 101, and the side wall of the light shield module 105 has a light-transmitting slit 401 with an angle matching the field of view of the AOI lens;
[0037] Magnetic quick-change interface 104: Located at the assembly interface between positioning module 102 and carbon fiber substrate 101, including magnetic ring and RFID chip inside the substrate;
[0038] Partitioned vacuum adsorption array 103: Silicone suction cups cover the central area of carbon fiber substrate 101 and are distributed around the light-transmitting hole 501.
[0039] The carbon fiber substrate 101 eliminates thermal deformation errors, while the thermal expansion coefficient of the traditional aluminum substrate is increased. The tilted air float nozzle avoids airflow disturbance to the optical path, which causes imaging jitter due to traditional vertical airflow. The magnetic quick-change interface 104 enables rapid shape change, while traditional screw fixation takes a long time. The adsorption array surrounds the light-transmitting hole to take into account both the fixation and detection space, while the traditional adsorption area obstructs the lens field of view.
[0040] The air pressure data of the air-bearing support unit drives the height compensation of the piezoelectric fine-tuning column; the output light of the fiber optic light guide channel 301 is misaligned with the spectral band of the coaxial light source.
[0041] Real-time PCB bending is offset by pneumatic piezoelectric closed-loop compensation, improving compensation accuracy. Layered identification of solder joint defects is performed by optical fiber and coaxial spectrum misalignment, identifying surface bridging / bottom layer cold solder joints.
[0042] Below the light-transmitting hole 501 is a downward-viewing lens module 502 containing a liquid lens; the inner wall of the light-transmitting hole 501 is coated with an anti-reflection film.
[0043] Liquid lenses enable millisecond-level zoom compatible with thicknesses from 0.1 to 5mm, while traditional lenses require manual focusing. The light-transmitting aperture is coated with an anti-reflective film to improve light transmittance, whereas traditional apertures have low light transmittance.
[0044] The bottom of the light shield module 105 is slidably engaged with the dovetail groove on the side of the substrate via a snap fastener; the positioning module 102 is engaged with the substrate via a tapered guide post and an elastic fitting.
[0045] The sunshade buckle and dovetail groove are used to resist vibration and displacement. Traditional screw fixing is easy to loosen. The tapered guide post and elastic sleeve are used to ensure repeated positioning accuracy. Traditional guide sleeves have large gaps.
[0046] The adsorption force of the partitioned vacuum adsorption array 103 is adaptively adjusted according to the product thickness; the RFID chip controls the partition activation of the adsorption array.
[0047] Adaptive adsorption force minimizes damage to flexible parts, while traditional fixed negative pressure can damage thin parts. RFID-activated partitioning allows the suction cup to operate only within the outline, improving efficiency.
[0048] An anti-reflective microprism film is attached to the inner wall of the light-transmitting slit 401; a buffer spring is provided at the bottom of the positioning module.
[0049] The microprism film has a higher ambient light suppression rate, while traditional light shields have a lower shielding rate. The buffer spring and magnetic impact force attenuation prevent the displacement of precision components.
[0050] The air flotation nozzles are distributed in a ring around the light-transmitting hole, and the airflow direction is inclined to the axis of the light-transmitting hole.
[0051] The annular inclined nozzle distribution results in better gas film uniformity, while the traditional single-sided gas supply has poor uniformity. The airflow avoids the optical path, resulting in lower imaging distortion compared to the traditional solution.
[0052] Working steps: First, place the product into the magnetic interface: place the new positioning module, then the RFID chip: automatically read the product ID, then send contour data / optical parameters through the controller, preload the adsorption zone through the vacuum array, and then perform product detection by setting the wavelength of the coaxial light source.
[0053] 1. Air-float non-contact positioning: The air-float nozzle sprays an inclined airflow to form a uniform air film to support the product: The air pressure sensor 201 monitors the pressure in real time and the piezoelectric ceramic fine-tuning column 202 compensates for the height, which solves the problem of product deformation caused by traditional mechanical clamping.
[0054] 2. Optical multi-dimensional imaging: Coaxial light source red light vertical illumination captures surface solder joint defects; fiber optic light guide pin a: infrared light 45° side supplementary illumination penetrates solder paste to detect underlying cold solder joints; liquid lens: millisecond-level zoom is compatible with products with a thickness of 0.1-5mm, solving the shadow blind spots existing in traditional single light sources.
[0055] 3. Dynamic closed-loop compensation: The downward-looking lens calculates the position deviation by shooting the positioning pin through the light-transmitting hole 501, and the piezoelectric ceramic compensates in real time, which solves the problem of low efficiency of manual adjustment.
[0056] 4. Intelligent adsorption and fixation: RFID reads the product outline and activates only the suction cups within the outline, solving the problem of damage to flexible parts caused by negative pressure throughout the entire area.
[0057] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.
[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. An AOI testing fixture for workpiece appearance inspection, characterized in that, include: Carbon fiber substrate (101): The surface is sandblasted and matte, and a light-transmitting hole (501) is opened in the center. Multiple air-floating nozzles are evenly distributed around the outer ring of the hole, and the nozzle axis is inclined towards the center of the light-transmitting hole. Detachable positioning module (102): Symmetrically fixed on both sides of carbon fiber substrate (101), the detachable positioning module (102) integrates: a ceramic positioning pin with built-in optical fiber guide channel (301), the output direction of the detachable positioning module (102) is inclined to the horizontal plane; and an air-bearing support unit with air pressure sensor (201) and piezoelectric ceramic fine adjustment column (202); Light shield module (105): Covering the carbon fiber substrate (101), the light shield module (105) has a light-transmitting slit (401) with an angle matching the field of view of the AOI lens on its side wall; Magnetic quick-change interface (104): located at the assembly interface between the positioning module (102) and the carbon fiber substrate (101), including the magnetic ring and RFID chip inside the substrate; Partitioned vacuum adsorption array (103): Silicone suction cups cover the central area of the carbon fiber substrate (101) and are distributed around the light-transmitting holes (501).
2. The AOI testing fixture for workpiece appearance inspection as described in claim 1, characterized in that: The air pressure data of the air-bearing support unit drives the height compensation of the piezoelectric fine-tuning column; the output light of the optical fiber guide channel (301) is misaligned with the spectral band of the coaxial light source.
3. The AOI testing fixture for workpiece appearance inspection as described in claim 1, characterized in that: Below the light-transmitting hole (501) is a downward-viewing lens module (502) containing a liquid lens; the inner wall of the light-transmitting hole (501) is coated with an anti-reflection film.
4. The AOI testing fixture for workpiece appearance inspection as described in claim 1, characterized in that: The bottom of the light shield module (105) is slidably engaged with the dovetail groove on the side of the substrate by a buckle; the positioning module (102) is engaged with the substrate by a tapered guide post and an elastic sleeve.
5. The AOI testing fixture for workpiece appearance inspection as described in claim 1, characterized in that: The adsorption force of the partitioned vacuum adsorption array (103) is adaptively adjusted according to the product thickness; the RFID chip controls the partition activation of the adsorption array.
6. The AOI testing fixture for workpiece appearance inspection as described in claim 1, characterized in that: An anti-reflective microprism film is attached to the inner wall of the light-transmitting slit (401); a buffer spring is provided at the bottom of the positioning module.
7. The AOI testing fixture for workpiece appearance inspection as described in claim 1, characterized in that: The air flotation nozzles are distributed in a ring around the light-transmitting hole (501), and the airflow direction is inclined to the axis of the light-transmitting hole (501).