In the past, quality inspection relied on experienced technicians' eyes; now, it can be entrusted to an AI system. Critical defects such as illegible markings or missing holes have a miss rate below 1%. Typical surface flaws like scratches and scuff marks are controlled within 2%, while major defects including dents, pressure injuries, and weak welds are kept under 5%.

I. Where Does Quality Inspection Face Challenges?

The four doors and two hoods (front and rear doors, engine hood, trunk lid) are crucial components of a vehicle’s exterior appearance and structural integrity. Defects such as scratches, cracks, rust, dents, and pressure damage on stamped parts, along with weak welds, misaligned welds, missing or excess welds on assembly lines, plus unclear markings and missing punch holes—18 types of defects often appear simultaneously on a single part, differing greatly in size, shape, and imaging characteristics.

Manual visual inspection suffers from low efficiency, inconsistent results depending on operator condition, and difficulty in documenting and tracing defects. Moreover, these parts are highly reflective curved surfaces, making defect detection even harder when illuminated.

II. How Does AI Work?

Big Bird Industrial's solution is straightforward—four steps:

1. Clear Imaging: Illuminating the same area from four directions and fusing multiple images makes previously hard-to-detect flaws—such as dents and edge warping—clearly visible.

2. Accurate Recognition: Different algorithms target different defects—deep learning segmentation models outline surface flaws pixel by pixel; object detection models count and locate weld points; template matching combined with OCR verifies markings; standard hole positions verify missing holes.

3. Precise Localization: The system converts detected flaw locations in images into 2D coordinates on the workpiece, then maps them into 3D space, directly instructing polishing robots where and how to grind.

4. Reliable Verification: After grinding, the system performs a final inspection to confirm complete removal of defects before passing the part, forming a closed-loop process.

III. What Are the Results?

Let numbers speak:

- Integrated detection of 18 defect types, fully covered by one system  

- Key defects (e.g., illegible markings, missing holes): Miss rate ≤1%  

- Typical surface defects (e.g., scratches, scuff marks): Miss rate ≤2%  

- Major defects (e.g., dents, burrs, edge warping, weak welds, misaligned welds): Miss rate ≤5%  

- Inspection cycle synchronized with production line, supporting full-line online inspection, automatic data archiving, and traceability of defects.

IV. Who Is Using It?

The solution has been successfully deployed at multiple OEMs—including Geely, Great Wall, Dongfeng Honda, and FAW-Volkswagen—as well as component manufacturers such as Sichuan Jian'an and Weichai Power. Products have earned repeat orders from customers. Related seam inspection methods have been granted a national invention patent (CN120543506A). The core product, the "Master's" series, won the Third Prize of China Machinery Industry Science and Technology Award.

V. Frequently Asked Questions

Q: What types of defects can it detect?  

A: 18 categories: surface defects (dents, scratches, scuff marks, cracks, rust, burrs, edge warping), welding defects (weak welds, misaligned welds, excess/missing welds), and illegible markings or missing holes.

Q: Can it replace manual inspection?  

A: Yes. It enables full-line online inspection synchronized with production pace, offering greater stability than human inspection, with automatic documentation and traceability of defects.

Q: Does it support automated grinding and rework?  

A: Yes. The system outputs 3D coordinates to guide polishing equipment, followed by automatic re-inspection after grinding, forming a closed loop of “inspection–grinding–re-inspection.”

Q: Which production lines is it suitable for?  

A: Supports both online and offline operations, customizable based on workpieces, production pace, and site conditions.

If you're struggling with quality inspection for four doors and two hoods or other automotive components, visit HuaNaiShi’s official website at cnisee.net or contact our sales team to receive a customized solution tailored to your production line.