Verifying Laser Marks

Machine-readable identification holds the key
to manufacturing efficiency

The following is condensed from an article by Chris Davis, vice president of DAPRA Marking Systems, from the April 2005 issue of Industrial Laser Solutions.

Machine-readable identification is quickly becoming a trend throughout many industry sectors, and is used to automatically identify a variety of products. Manufacturers are marking parts with machine-readable, permanent, two-dimensional (2D) data matrix codes that are placed directly on the part itself. The part can then be tracked throughout its entire life cycle, including the manufacturing and supply chain operations. This is called Direct Part Mark Identification (DPMI) or Auto-ID.

DPMI enables manufacturers to improve manufacturing process performance, identify quality defects through in-service tracking, eliminate manual part data-entry errors, support data logging and automated data collection, increase yields and reduce the direct and indirect costs of manufacturing. Many manufacturers also rely on Auto-ID to track high-value parts to prevent theft or counterfeiting, identify parts for maintenance and returns and to resolve any warranty issues and liability claims.

Common application methods are laser, dot peen and electro-chemical etch. For laser-produced marks, IAQG quality metrics measure the following parameters to determine if a 2D mark is acceptable, and assign a grade based upon the following factors: cell shape, contrast level between the marking and its substrate or cell fill of 60-105% of the nominal cell size.

Verification is an excellent real-time method to keep the marking operation in control and to standard, thus helping manufacturers improve their processes through direct part marking.

Click here to read the full article online.