1. Why DPM
Labels burn, peel, or wear off in harsh environments. Direct part marking engraves the symbol into the surface so it lasts for the life of the part. Critical for industrial applications where [barcode systems](/barcode-generator) aren't durable enough.
2. Methods
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Laser marking: High precision, small modules, good for electronics and medical parts.
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Dot peen: Pressed dots into metal. Works on rough surfaces, and modules are dots rather than squares.
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Chemical or electrochemical etching: Good contrast on stainless steel.
3. Reading Challenges
Reflective, curved, or low-contrast surfaces need controlled lighting and industrial imagers. Quality guidance for these marks is given in ISO/IEC TR 29158. Test readability with specialized [QR scanners](/qr-scanner) designed for DPM, not consumer phone cameras.
4. Design Tips
Use Data Matrix where space is tight, error correction at the higher end, and verify every mark with a dedicated verifier rather than a phone. Plan module sizing with our [QR size calculator](/qr-size-calculator) before marking. For QR codes, use our [error correction simulator](/error-correction-simulator) to understand damage tolerance. Follow our [QR placement guide](/qr-placement-guide) for positioning on complex part geometries. Test final marks with our [printed QR tester](/printed-qr-tester) methodology adapted for metal surfaces.
Putting this into practice
Start with the smallest real test you can run. Generate the code, print it at the exact size you plan to use, and scan it with two different phones in the lighting where it will live. Check that the destination page loads quickly on a mobile connection and that the call to action next to the code tells people what they will get. If anything feels slow or unclear, fix it before you print a full batch, because reprints cost more than a short test. Keep a note of the size, material, and placement that worked so the next batch starts from a proven setup.
Common mistakes to avoid
The most common mistakes are easy to avoid once you know them. Long payloads make modules tiny, low contrast makes edges hard to read, and text placed too close to the border eats the quiet zone the scanner needs. Covering a corner finder pattern with a logo or a sticker breaks detection entirely, and a code placed behind glare or on a curved surface fails even when the print is perfect. Review each of these points on a proof copy, and treat any failure as a reason to adjust the design rather than a reason to blame the scanner.
Quick checklist
- Keep the payload as short as practical so modules stay large.
- Keep dark modules on a light background with strong contrast.
- Leave a clear quiet zone on all four sides of the symbol.
- Test the printed code at the real viewing distance and lighting.
- Confirm the destination page loads fast on a phone.
- Recheck the code after any change to the link, design, or placement.
