The purpose of reading is to locate and decode a mark as quickly and reliably as possible in order to output the data. A good reader can handle variations in marking method, surface texture, etc., and can read at very low resolution.
Verification, however, is the process of inspecting and documenting whether marks conform to industry and internationally accepted standards. Once inspected, the verifier will output a grade of the code's quality. Verifying systems require higher resolution of the code for verification (5-10 pixels per cell) and all environmental variables including lighting and part position must be controlled so all mark attributes can be measured.
Cognex recommends that you verify codes immediately after marking and before parts enter the downstream manufacturing process in order to prevent no reads. Additionally, some industries such as the U.S. Department of Defense require that marks pass verification inspection to mark quality standards such as AIM (Association for Automatic Identification and Mobility) Direct Part Mark (DPM) Quality Guideline DPM-1-2006 as part of vendor contract compliance for part delivery.
Download our DPM quality standards white paper to learn more
