What is Check Plots
Check plots are specialized pen plots or overlays that are used for the purpose of verification and quality control, specifically designed for checking purposes only, and are not intended for final production or manufacturing. Check Plots are created by representing pads as circles and thick traces as rectangular outlines, rather than using filled-in artwork. This technique enhances the transparency of multiple layers, allowing for easier visual inspection and identification of any potential issues or discrepancies.
They ensure the accuracy and alignment of various processes in PCB manufacturing and assembly. For instance, in the case of stencil printing, check plots are overlaid on the PCB to verify that the stencil pattern matches the board. This helps to ensure that solder paste will be accurately printed on all pads that require devices.
In the case of multi-layer PCBs, check plots are created for each layer using Mylar artwork. These overlays include pin registration holes, which facilitate physical alignment and verification of the overall PCB layout. This step is crucial in ensuring that all layers are correctly aligned, resulting in a functional and reliable final PCB product.
Check plots can also be utilized in the context of thick film screen printing. By comparing the overlay with the screen and the intended print pattern, any errors or inconsistencies can be identified and addressed before proceeding with the printing process. This ensures the accuracy and quality of the printed thick film.