Application of visual inspection equipment in the gemstone industry - Xianghongyu

Applications of visual inspection equipment in the gemstone industry

The gemstone industry has extremely stringent requirements for product quality, whether natural or artificial, its dimensional accuracy and appearance integrity directly affect the value of the finished product and customer satisfaction. Traditional manual testing methods rely on experience, are inefficient, and are easily influenced by subjective factors. With the development of technology, automated inspection equipment based on computer vision has gradually become the core tool of quality control in the gemstone industry. This article will focus on the application of visual inspection equipment in gemstone size measurement, cosmetic defect detection, and how its glass turntable structure optimizes the inspection process.

1. The core function of visual inspection equipment

1. Size Detection: Accurately controlling the size of each millimeter
of gemstones directly affects their cutting process and setting matching. For example, diamond diameter, table proportions, girdle thickness and other parameters need to be at the level of 0.01 mm. Visual inspection equipment captures gemstone images with high-resolution industrial cameras such as 50 million pixel CCDs, combined with image processing algorithms, to achieve the following functions:

• Multi-dimensional measurement: Automatically calculate the length, width, height, symmetry and other parameters of the gemstone.

• Contour Analysis: Identifying irregularly cut stones (such as facet angle deviations).

• Batch inspection: Thousands of gemstones can be detected per hour, far more efficient than manual labor.

2. Appearance Defect Detection: Spotting imperfections that are difficult to identify with the naked eye Gemstone defects are divided into surface defects (scratches, chipping) and internal defects (cracks, bubbles).
The vision equipment achieves full-angle coverage through multi-light source combination and algorithm optimization:

• Surface inspection: Uses ring light source + high magnification lens to capture small scratches (such as 0.05 mm level).

• Internal Detection: Using transmitted light sources and polarization technology, internal cracks are found through the surface of the gemstone.

• Intelligent Classification: The system automatically grades defects based on their type (e.g., impurities, stains) to assist in pricing decisions.

2. Glass turntable structure: a "rotating stage" for efficient detection

In order to improve the inspection efficiency, the visual inspection equipment often adopts the glass turntable structure, and its design features are as follows:

1. Transparent material: The 360° non-dead angle imaging
glass turntable has strong light transmission, allowing the bottom camera and light source to penetrate upwards, and the top camera can achieve synchronous shooting of the upper and lower surfaces of the gemstone. For example, when inspecting sapphire ring faces, the device can capture 10-20 angles during rotation, ensuring no blind spots.

2. Stable rotation: The balance
of accuracy and speed of the turntable is driven by a servo motor, and the speed is adjustable (such as 10-60 rpm), which can not only change the material quickly, but also avoid the displacement of the gemstone due to inertia. The measured data shows that the positioning error of the glass turntable can be controlled within ±0.02 mm, which meets the needs of high-precision inspection.

3. Modular design: Compatible with different specifications of gemstone
turntables can be equipped with customized fixtures (such as silicone suction cups, V-shaped card slots), compatible with gemstone sizes from 3mm-30mm. For special-shaped gemstones (e.g., heart-shaped, drop-shaped), stable fixation can also be achieved by changing fixtures.

3. Practical application cases

After the introduction of visual inspection equipment in a jewelry processing factory, the production process was significantly optimized:

• Efficiency improvement: The detection speed has been increased from 200 capsules/day manually to 5000 capsules/day.

• Cost reduction: Reduce quality inspection manpower by 80%, saving more than 500,000 yuan per year.

• Controllable quality: The customer complaint rate has decreased by 90%, especially solving the industry pain point of "small crack missed detection".

Typical testing process:

1. Feeding: Manually or robotic arms place gemstones on glass turntable fixtures.

2. Rotation scanning: The turntable drives the stone to rotate, and multiple cameras take images simultaneously.

3. Algorithm analysis: The system compares the standard parameter library in real time and marks the non-conforming products.

4. Sorting output: The pneumatic device ejects the defective gemstones into the recycling bin, and the qualified products enter the next process.

4. Technical advantages and future trends

The advantages of visual inspection equipment are not only "fast" and "accurate", but also in its non-contact inspection characteristics – avoiding wear and tear on the surface of the gemstone with traditional contact measuring tools. In addition, the equipment records the detection data of each stone to provide a basis for process optimization.

In the future, with the iteration of technology, two directions are worth paying attention to:

1. AI deep learning: Train the model through a large number of defect samples to improve the recognition rate of complex defects (such as mesh cracks).

2. Multispectral imaging: Combine infrared and ultraviolet light sources to further analyze the material and internal structure of gemstones.

epilogue

Visual inspection equipment is reshaping the quality standards of the gem industry with its high precision and efficiency. As its core carrier, the glass turntable structure shows unique value in terms of stability and expandability. For enterprises, the introduction of such equipment is not only a technological upgrade, but also a key step from "experience-driven" to "data-driven". In the future, with the improvement of intelligence, visual inspection may become the "quality gatekeeper" of gemstones from raw materials to finished products.