Recently, the State Administration for Market Regulation and the National Standardization Administration jointly issued the latest inspection methods and criteria for flat glass (GB 11614-2022), involving thickness deviation inspection, minimum point defect and allowable number confirmation, and optical deformation inspection. , transportation packaging requirements, etc., the new standard will be implemented on August 1, 2023.
This update of the flat glass standard mainly includes the following modifications and changes:
- Added iridescent definition;
- According to the appearance quality, it is divided into three grades of qualified products, first-class products, and excellent products, and changed to ordinary grades and high-quality processing grades;
- Changed thickness deviation and thickness difference;
- Changed the minimum and allowable number of point defects;
- Changed the requirements for optical distortion;
- Changed the requirements for transmittance deviation and color uniformity of bulk tinted flat glass;
- Added iridescence requirements, inspection methods and judgment rules.
Due to its transparency and certain strength, glass is widely used in daily life, such as glass cups, glass bottles, mirrors, windows, car windows, etc. Glass is fragile, and once broken, it is easy to cause serious injury. Therefore, Inspection of glass products is necessary.
In order to ensure that the glass products produced by suppliers meet the quality and safety standards of the target market, and at the same time ensure that the factory delivers on time, the initial production inspection, mid-production inspection and final production inspection can be carried out for glass products.
The general inspection points of inspectors at the glass product inspection site are as follows:
Glass product inspection 1. Product size measurement 2. Product weight inspection 3. Proportion and quantity inspection 4. Appearance inspection 5. Tape test for printed patterns 6. Hot and cold impact test 7. Glass tension test 8. Capacity test 9. Slope stability test 10 . Bottom stability test 11. Water leakage test 12. Barcode scanning test 13. Product packaging inspection
1. Product size measurement
For flat glass, the length, width and thickness need to be measured, and the specific deviation should refer to Table 1; for glass products such as cups, the length, width, height and thickness should be measured. If the customer has no special requirements, the deviation should be controlled within 3%.
Tools used: Metal ruler or steel tape, thickness gauge or spiral micrometer.
Allowable value of thickness deviation of flat glass
Glass product size measurement
2. Product weight check
Measure the weight of a single product and the weight of the whole box after packaging. If the customer has no special requirements, the single weight deviation is controlled within 3%, and the whole box weight deviation is controlled within 5%.
3. Proportion and quantity check
If the product is different in size, color, style, etc., it is necessary to check the corresponding quantity and record。
4. Visual inspection
Visual inspection is an important part of glass inspection. It is necessary to check in detail whether there are defects such as air bubbles, scratches, and air bubbles. For details, please refer to the common defects/defects in glass inspection below.
5. Tape test of printed pattern
For printed patterns on glass, a coating adhesion test should be performed:
Use 3M 600 tape to do the adhesion test on the printed surface, and the content should not fall off 10%.
6. Thermal shock test
Put water at 85±5 degrees Celsius in the product for 3 minutes; pour out the hot water and quickly put water at 35±5 degrees Celsius in the product for 3 minutes. After the test, the glass product should be free of water leakage or breakage.
7. Glass Tension Test
Use the tension tester provided by the factory to detect the degree of thermal expansion and tension of the glass, which must meet the customer’s requirements.
Glass Tension Test
8. Capacity testing
Fill the product with water, then pour the water into the measuring cup and read the value. The deviation of the measured value should be controlled within a tolerance of +/- 3%.
9. Slope Stability Test
Put an equal volume of water into the glass product and place it on a slope with an inclination of 10 degrees. The product should be placed on the slope without slippage.
10. Bottom stability test
Place the glass product on a flat horizontal surface to check whether it is stable and not inclined. If it is shaking, it is an unqualified product.
11. Water leak test
Many glass products are used to contain liquids and therefore require a water leak test.
Glass devices with sealing rings, such as glass water bottles, glass lunch boxes, test method: Pour a certain amount of water into the device, seal it, and invert it for 3 minutes to check for water leakage.
Glass products without sealing ring: Fill the product with water or add the same amount of water to the design volume, and place it on white paper for 5 minutes. The white paper should be free of any water marks after the test.
12. Barcode Scanning Test
The barcode on the glass product or packaging color box should be clearly printed and scanned with a barcode scanner, and the result is consistent with the product.
13. Product packaging inspection
Since glass is fragile, the packaging of glass products generally needs to meet the following requirements:
a. There should be signs or labels on the glass packaging, indicating the product name, manufacturer, registered trademark, factory address, quality grade, color, size, quantity, production date, standard number and light handling, fragile, rain-proof and moisture-proof signs or words;
b. Glass packaging should be convenient for loading, unloading and transportation, and protection and anti-mildew measures should be taken. Generally, it is recommended that glass products be packed in wooden boxes.
Common visual inspection defects/defects in glass inspection:
Common appearance defects of glass products are: bubbles, inclusions (impurities), spots (dirt), indentations, scratches, sharp edges, surface cracks, etc. The following are the latest standards and requirements for point defects (including bubbles, inclusions, spots):
Appearance quality inspection standard of ordinary flat glass
Common appearance inspection defects/defect pictures:
Bubble:
Inclusions (impurities):
Spots (dirt):
Indentation at seam:
Scratches:
Sharp corners:
Surface cracks:
The above are the general inspection methods for glass products. Due to the variety of styles and functions of glass products, the specific on-site inspection methods can be adjusted according to customer needs.
Post time: Sep-01-2022