Technologies: Direct Part Marking

Direct Part Marking (DPM) is a technology used to produce two different surface conditions on an item. These markings can be created by laser etching, molding, peening, etc.

Traditional print quality measures are based on the assumption that there will be a measurable difference between dark and light elements of a symbol. Because DPM symbols frequently do not have sufficient contrast between elements intended to be dark and light, it is often necessary to provide specialized lighting in order to produce highlights or shadows in order to distinguish the various elements of the symbol. (See examples below.)

DPM Quality Guidelines Document

Acknowledging that current ISO print quality specifications for matrix symbologies and two-dimensional print quality are not exactly suited for DPM symbol evaluation, an ad-hoc committee under the supervision of the AIM Technical Symbology Committee developed a guideline to act as a bridge between the existing specifications and the DPM environment in order to provide a standardized image based measurement method for DPM that is predictive of scanner performance.

The document describes modifications which are to be considered in conjunction with the symbol quality methodology defined in ISO/IEC 15415 and two-dimensional symbology specifications. It defines alternative illumination conditions, modifications to the measurement and grading of certain parameters and the reporting the grading results.