No matter how detailed the procurement contract is, it still relies on the acceptance of the goods upon arrival to provide a guarantee. Many buyers lack simple and easy to implement inspection methods and can only accept products as soon as they look similar. In fact, with the three-step low-cost sampling method, most of the problematic batches can be screened out within five minutes. Step 1: Look at the edge - determine the color of the raw material. Take a piece of lens and observe the edge section under natural light. The edges of the brand new PC material are transparent and the color is uniform; Products mixed with recycled materials or impersonated with PS materials often have white gray edges and visible impurities, air patterns, or color differences. This step does not require any tools, but it can filter out the most typical inferior materials. If the edges are foggy or have opaque particles, it is recommended to return the entire batch for inspection. Step 2: Test toughness - Verify the impact resistance by holding both ends of the lens with both hands and slowly applying bending force before releasing it. Qualified PC lenses have good flexibility and can quickly rebound without leaving any marks when released; Poor quality lenses may show whitening marks when bent, and in severe cases, they may directly crack. It should be noted that this test is recommended to use the sample pieces provided by the supplier to avoid damaging the products for sale; For brittle samples, the supplier should be required to provide a written explanation of the composition of the raw materials. Step 3: Look at optics - check for distortion imaging. Raise the lens in front of your eyes and observe distant straight objects (such as window frames and light tubes) through the lens. High quality lenses produce straight and distortion free images; Lenses with optical distortion can cause significant bending or wavy deformation of straight lines when the line of sight moves. Lenses with excessive distortion can cause visual fatigue and dizziness for wearers, and are a frequent source of complaints for long-distance cycling. The three-step sampling of edge inspection, toughness testing, and optics inspection has almost zero cost, but it can effectively block batches of raw materials and processes that do not meet the standards. Suggest including these three items in the arrival acceptance process and requesting suppliers to provide cross validation of inspection reports. We welcome customers to provide samples and conduct random inspections for review. The inspection report can be checked with the batch.a