What is Aperture Wheel
An aperture wheel is a component or mechanism used in the photoplotter machine during the PCB manufacturing process. It serves as a holder for different aperture definitions, which are physical openings that control the exposure of light onto photographic film. These apertures determine the shapes and patterns that are created on the film, ultimately translating into the desired circuitry on the PCB.
The aperture wheel is an important factor in CAM (Computer-Aided Manufacturing) process, where the CAM data includes instructions on how to utilize the apertures. By flashing different apertures on the film, various pad sizes and track thicknesses can be achieved. The size and shape of the apertures on the wheel are carefully defined to ensure precise and accurate circuitry reproduction.
While advancements in technology have led to the use of laser plotters that simulate aperture shapes digitally, the concept of the aperture wheel remains significant. Every CAM file requires an aperture list, which contains the definitions of the apertures to be used in the manufacturing process. These aperture definitions, stored on the aperture wheel, are essential for the photoplotter operator to understand the desired patterns and shapes.
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