A defect found right after printing can be corrected by simple PCB cleaning while it takes extensive rework and repair if it does not show up until after reflow soldering. This also involves the risk of damaging the PCB. For safety-critical products, repair is not an option anyway.
The inline system MIRTEC MS-11 detects defects such as insufficient or excessive solder paste, clogged stencils, misalignment, solder bridges, deformation of depots, etc. before the placement process. This allows a process adjustment which can improve quality on a sustained basis. MS-11 uses shadow-free Moiré technology and a high-end 4 Megapixel camera in order to achieve post-print PCB inspection with optimum precision.
Image processing based on the Moiré phase shift method is by far the most precise way of post-print solder paste profile inspection. This method projects light in grid or stripe patterns on the solder paste depot. The light pattern is being moved step by step along the depot and a downward looking high resolution CCD camera acquires the resulting images. The MS-11 uses a “shadow-free”
Among the most important advantages of the Moiré technology are the superior resolution at determining the solder paste thickness and the impassivity towards external faults like irregularities of the PCB structure or towards contingent bending of the substrate. The final result is a highly precise 3D image from which the system can precisely calculate volume and shape of the depot.
MS-11 is based on the same robust platform as the AOI system Mirtec MV-7xi. The inspection heads are exchangeable among both systems which guarantees maximum flexibility with regard to the inspection process.
