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Modular AOI System Starts at the Bottom
The SpectorBOX AOI provides a modular solution for inspecting THT and SMT PCBs.

Growing complexity of printed-circuit boards (PCBs) and PCB assembly methods drives the needs for effective inspection solutions for examining the surface-mount technology (SMT) and through-hole technology (THT) used throughout many PCBs. Fortunately, an inline, bottom-side PCB inspection system has been developed containing as many as nine cameras per side, and can be configured for simultaneous top and bottom PCB inspection with as many as 18 cameras to address the growing complexity of PCBs and PCB assembly techniques.

As these trends in PCB assembly impact a growing number of application areas, such as for high-power automotive electronics, automated optical inspection (AOI) systems provide an essential means of checking SMT and THT assemblies for quality and reliability, since rework on these PCBs is increasingly forbidden. AOI has become a solution of choice for checking the quality of production PCBs and helping to improve production yields for these boards.
The modular design of the SpectorBOX AOI system allows positioning at almost any check point along a conveyer belt.

The production equipment and factory configurations for wave soldering and selective soldering can be quite different than the production lines employing interfaces meeting Surface Mount Equipment Manufacturers Association (SMEMA) standards common to convection reflow production lines. This makes it difficult to apply conventional AOI systems in cost- and space-effective manners. Inspection performed from the bottom up provides a fundamental solution, but circuit assemblies in frames are typically returned to operators for removal on conveyers located very close to floor level, making inspection all the more difficult. Intermediate board flipping stations and large top/bottom configurations of conventional AOI systems have been used for inspection in these cases, often with less-than-ideal results. Because of the absence of standardized interfaces, such attempts at integrated inspection solutions are further characterized by the need for one-off custom designs.

An AOI Solution
Fortunately, an AOI solution has been developed with excellent inspection capabilities and the mechanical flexibility required to enhance productivity. The SpectorBOX system from Marantz Electronics Ltd. (MEK) has been optimized for checking wave- and selective-soldered PCBs with THT and SMT components, and can inspect PCBs inside solder frames directly on existing production-line conveyer belts. The AOI system can be positioned at any conveyer feed or return point, and its compact mechanical design allows it to be positioned below existing return and feed conveyers. It features a low-profile inspection head for checking THT assemblies as close as a mere 280mm above a production floor. Elimination of flipping conveyers and ease of integration with existing conveyer systems can save as much as 75 percent in cost and floor space compared to other inspection systems.

Without increasing the inspection system footprint, simultaneous top-bottom inspection capabilities can be achieved by combining two modules in one SpectorBOX system, each with a top or bottom camera and eight side cameras. The system performs effective wave solder inspection by means of MEK Meniscus Profiling, using 360-deg. multiple-angle, multiple-color lighting, including line-sourced diffuse-on-axis-light (DOAL) coaxial prism illuminators and high-resolution telecentric optics.

In addition to the top or bottom modules with nine cameras, the modular AOI system can be equipped with a Z-axis moveable optical head for focusing and optimal positioning. This optical head can account for warping of a PCB and for different PCB heights when in their solder frames. The X-Y drive gantry delivers 1500 cps/min inspection capability with precision and accuracy. The system includes an automatic microscope function to verify defects on the repair station, without need of operator intervention. Each modular SpectorBOX system features a general-purpose input/output (I/O) configuration to simplify the interface with new or existing conveyer systems. It is currently available in sizes to 550 x 520mm (21.7 x 20.5-in.).

Contact: MEK (Marantz Electronics Ltd.), MEK Americas, 5550 Painted Mirage Road, Suite 320, Las Vegas, NV 89149 702-818-1706 E-mail : Web: or Christopher Associates, 3617 W. MacArthur Blvd., Santa Ana, CA 92704 714-979-7500 fax: 714-557-6904 Web:

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