Laser marking visual positioning

In the field of industrial-grade precision manufacturing, visual laser marking technology has become one of the core technologies for achieving product traceability, process control and quality management. As an innovative representative in this field, Jiangpin Technology's equipment integrates three mainstream visual positioning methods: side-axis, external coaxial, and internal coaxial. Through the collaboration of high-precision CCD cameras and laser galvanometers, it significantly enhances the accuracy and efficiency of marking. The following is an in-depth analysis from three aspects: technical principles, performance comparisons, and industrial applications.

I. Technical Principles and Characteristics of the Three Major Visual Positioning Methods
Off-Axis Vision system
The side-axis vision laser marking control system is installed beside the optical path system, which is the side-axis vision laser marking control system. Its camera is installed at a fixed Angle on the side of the laser galvanometer, and positioning is achieved through image stitching and coordinate transformation algorithms. The advantages lie in its simple structure and low cost, making it suitable for large-format marking. However, it relies on high-precision calibration and is prone to parallax errors (usually ±0.1mm) on curved surfaces or workpieces with large height differences. It is mostly used in packaging and sheet marking scenarios where precision requirements are not strict.

External Coaxial Vision system
External coaxiality refers to the coaxiality of the vision system and the laser outside the optical path system. The camera is coupled with the laser path through a beam splitter to achieve the coincidence of the laser focus with the center of the imaging field of view. Jiangpin Technology adopts this method in PCB marking machines, combined with Mark point positioning technology, with an accuracy of ±0.05mm. Its advantage lies in eliminating parallax, making it particularly suitable for QR code engraving on multi-panel boards or flexible circuits (FPCS), and supporting high-speed processing of 60-80 codes per minute. However, the optical path structure is complex and the maintenance cost is relatively high.

Integrated Coaxial Vision system
Internal coaxial refers to the installation of the vision system inside the galvanometer control system, achieving coaxial optical paths. The miniature camera is directly integrated into the galvanometer optical cavity, and the imaging optical path is completely coaxial with the laser optical path. This is currently the most accurate solution (up to the μm level), especially suitable for marking micro-devices such as microplates and medical stents. Jiangpin Technology has applied this technology in its high-end models, solving the problem of curved surface focusing through real-time Z-axis focusing while reducing positioning time by more than 25%.

Ii. Performance Comparison: Measured data on accuracy, speed and efficiency
The performance of the three systems in industrial scenarios can be clearly compared through the following table:

The external coaxial system reduces manual intervention through the linkage of CCD automatic positioning and post-printing reading code, shortening the production line switching time by 70%.

The coaxial system adopts high-speed galvanometer (scanning speed > 3000mm/s) and adaptive filling algorithms (such as bow filling), increasing the speed by 40% in fine graphic marking.

Iii. Cases of In-depth Adaptation to Industrial Application Scenarios
PCB full-process traceability
In electronic manufacturing, the external coaxial marking machine of Jiangpin Technology can engrave 1.5×1.5mm micro QR codes on the surface of green oil/black oil PCBS and connect to the upper and lower board machines through the SMEMA interface to achieve fully automatic assembly line operations. The equipment automatically reads the QR code and feeds it back to the MES system. Defective products will be alarmed immediately, replacing the consumable cost of traditional inkjet coding.

Marking of precision medical devices
The coaxial system is used for marking polished curved surfaces such as bone nails and artificial joints. It forms permanent marks through a thermochromic mechanism (non-ablation), avoiding material stress deformation 46. Compared with mechanical engraving, the yield rate has increased to 99.9%.

The flexible production line can be switched rapidly
The side axle system demonstrates flexibility in the automotive parts production line. By changing fixtures and software preset solutions, it can switch between different workpieces for marking within 10 minutes, supporting the mixed production of multiple materials such as metal signs and rubber parts.

Iv. Technological Evolution Direction: Intelligence and Integration
Future visual laser marking technology will break through in three dimensions:

AI visual compensation: Predict the thermal deformation of materials through deep learning and dynamically adjust the marking path (such as the expansion offset of copper materials due to high heat);

Multispectral fusion: Ultraviolet/green/fiber lasers work in coordination with vision systems to adapt to all scenarios from silicon wafers to composite materials;

Modular design: The new generation of equipment from Jiangpin Technology supports rapid insertion and removal of side-axis and external coaxial lenses, meeting multi-precision requirements with a single machine.