Overview
ISO/IEC TR 24720:2008 provides comprehensive guidelines for direct part marking (DPM) - a range of techniques for applying permanent, machine-readable symbols directly onto items such as components, parts, and products. This standard, developed by ISO and IEC, is crucial for organizations implementing automatic identification and data capture (AIDC) systems. DPM eliminates the need for labels or tags, ensuring robust identification and traceability throughout a part’s lifecycle, even under harsh operating conditions.
Employing both intrusive (subtractive) and non-intrusive (additive) marking methods, ISO/IEC TR 24720:2008 delivers practical advice on method selection, surface preparation, marking location, protective coatings, and the quality management of machine-readable symbols. While it does not encode the data content itself, it assists manufacturers in directly marking parts with readable codes that endure environmental and operational stresses.
Key Topics
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DPM Methods:
- Intrusive techniques: Physically alter the item’s surface (e.g., dot peen, laser etching, chemical etching, engraving, stamping).
- Non-intrusive techniques: Add material to the surface (e.g., ink jet printing, laser bonding, screen printing, stencil, liquid metal jet).
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Marking Method Selection:
Several factors influence method choice, such as:
- Material type (e.g., metals, plastics, ceramics)
- Surface geometry and condition
- Operational and environmental requirements
- Marking location and contrast needs
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Surface Preparation:
Preparing the marking area is vital for legibility and durability. Preparation may involve:
- Cleaning to remove contaminants
- Smoothing or machining surfaces
- Applying additives or coatings for enhanced contrast or corrosion resistance
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Protective Coatings:
Methods like clear anodizing, lacquer, thin film deposition, and chemical conversion coatings protect the mark and the part, ensuring longevity.
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Symbol Quality and Verification:
Mark quality impacts readability. The standard recommends verification using optical equipment to ensure consistent, high read rates and minimize costly identification errors.
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Human Readable Marking:
Whenever feasible, encode data should also be presented in human-readable form near the machine-readable symbol for redundancy.
Applications
DPM is vital across industries that require permanent, tamper-resistant identification for quality assurance, safety, and traceability. Notable applications include:
- Aerospace and defense:
Ensuring traceable lineage of mission-critical components.
- Automotive manufacturing:
Tracking parts through assembly and in-field maintenance cycles.
- Electronics:
Identification of PCBs and high-value assets.
- Medical devices:
Compliance with regulatory requirements for unique device identification.
- Industrial machinery:
Asset management and workflow automation.
Benefits of DPM:
- Withstands exposure to harsh environments, abrasion, or chemical processes
- Reduces risk of lost or mismatched labels
- Supports automated data capture and efficiency in supply chains
- Enhances product lifecycle management and counterfeiting deterrence
Related Standards
ISO/IEC TR 24720:2008 is part of a suite of standards supporting automatic identification and data capture technologies. Notably related standards include:
- ISO/IEC 19762
- Part 1: General terms for AIDC
- Part 2: Optically readable media (ORM)
- ISO/IEC 15415
- Specification for two-dimensional symbol print quality
- ISO/IEC 15416
- Linear barcode symbol quality test specifications
- ISO/IEC 29158
- Direct part mark (DPM) quality measurements
For manufacturers and supply chains aiming for global consistency and reliability, adherence to ISO/IEC TR 24720:2008 ensures best practices in part identification, code durability, and AIDC system implementation.