1. Background IntroductionCurrently, the new energy vehicle industry fully adopts Direct Part Marking (DPM) codes. DPM codes are characterized by high data density, storing a large amount of information in a small space. They are durable through a matrix structure, remaining readable even after partial damage. Different data types are encoded, and error correction is included to improve resilience. DPM codes help identify and monitor components during the manufacturing process, and accurate data acquisition is a fundamental aspect of achieving superior quality control in automotive manufacturing.Currently, labels are typically affixed to workpieces. However, labels have significant drawbacks. After a certain period, the DPM code information on the surface of the label becomes blurred, and the label is easily damaged by impacts or sharp objects, leading to difficulties in identification and loss of information traceability.Laser marking is a powerful technology that can create permanent marks on material surfaces and simultaneously clean the marks. With technological advancements and market demands, laser marking technology is gradually replacing label affixing.
Figure 1 Battery Cover Components
Figure 2 Laser Engraving Principle Diagram
2. Engraving RequirementsDPM codes need to be engraved on automotive aluminum alloy parts. A scanning gun is required to identify the quality level of the engraved DPM codes, with an identification level of 3 or higher. The engraving cycle time (range: 76×38mm) should be ≤70s. The engraving content consists of three parts: background scanning, hidden code, and visible code.
- Workpiece Background Scanning: For DPM codes on metal parts, the surface of the parts has reflective properties. When using laser equipment to read the barcode, a mirror reflection area will form on the metal surface, affecting the clarity of the QR code characters, making it difficult to read the DPM code or resulting in a low identification level. Therefore, the surface needs to be scanned before engraving to enhance the identification contrast.
- Hidden Code: The hidden code is the QR code, containing information such as the part's unique number, airtightness value, and time.
- Plain Code: The plain code contains some information from the coded code; these are visible characters, facilitating the observation of part information by personnel.
Figure 3: DPM Code Illustration
