Glare and low contrast
Highly reflective or dark surfaces may need controlled illumination geometry to reveal cell boundaries.
DPM code inspection
Direct part mark Data Matrix verification on real components
Read and assess laser-marked, dot-peened and etched Data Matrix codes on metal, plastic and other industrial parts under controlled production conditions.
Short answer
Surface-specific imagingDPM Data Matrix verification needs imaging and illumination designed for the marked surface. ISO/IEC 29158:2025 adapts the two-dimensional quality method for direct part marks and defines alternative lighting and reporting conditions.
The mark and the component create one optical problem
Laser annealing, laser engraving, dot peen and chemical etching produce very different cell shapes and reflectance. Machining marks, coatings, curvature and oil can further change the image as the part rotates or moves.
A production project should therefore test the worst credible surfaces and mark positions, not only a perfect sample. Where formal grading is required, the applicable illumination and calibration method must be stated; where the goal is reliable production reading, the acceptance test should still define realistic limits.
Common failure modes
What a DPM trial should challenge
Curvature and perspective
Code position, working distance and part rotation can alter module shape and apparent quiet zones.
Cell damage or inconsistency
Shallow dots, over-marking, debris and process drift can reduce decoding and quality margin.
Motion and presentation
Exposure time, trigger accuracy and fixture repeatability determine the captured production image.
Primary reference: ISO/IEC 29158:2025 — direct part mark symbol quality test specification.
Prove the optical window
Request a DPM trial Send representative components and known failures
We can trial lighting, resolution, reading margin and data checks before final system hardware is selected.
Technical content reviewed by the Oxford Vision Systems engineering team. Updated 26 August 2026.
Common questions
Direct answers for project teams
Concise answers to the questions manufacturers ask when defining a barcode inspection application.
Ask an engineerWhat is a direct part mark Data Matrix code?+
It is a two-dimensional code marked directly onto a component rather than printed on a separate label. Common marking methods include laser, dot peen and chemical etching.
Why can a standard barcode reader struggle with DPM codes?+
Direct marks may have low or uneven contrast, specular reflections, surface texture, curved geometry or incomplete cells. The reader, lens and illumination must be selected for the actual surface and mark.
Which quality standard applies to direct part marks?+
ISO/IEC 29158:2025 defines modifications to the ISO/IEC 15415 symbol-quality methodology for direct part marks, including alternative illumination conditions and reporting requirements.
Can DPM Data Matrix codes be verified while parts are moving?+
Often yes, but the smallest module, motion, orientation, working distance, surface finish and required grade must be proven with representative parts at realistic handling conditions.