Empty cans must have a supplier's factory inspection report upon arrival. The contents of the factory inspection report include at least but not limited to the following aspects: can appearance, aluminum specifications, aluminum thickness (excluding paint), paint specifications, main dimensions, boiling performance, corrosion resistance, paint model, inner coating integrity, axial bearing pressure, compressive strength, inner coating adhesion; external inspection reports must be provided every six months;
Empty can sampling rules: The same manufacturer, the same production line, the same production date, and the same day of delivery are considered as one inspection batch; if the batch is >80 plates, one can is randomly selected from each plate; if the batch is ≤80 plates, one can is randomly selected from each plate, and then randomly selected until the total number reaches 80 cans;
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Acceptance requirements for aluminum easy-open two-piece cans |
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Item |
Quality standard | Defect classification | Inspection level | Acceptable quality level AQL | Batch range (Note 1) | Number of samples |
Judgment array Ac Re |
| Appearance | 1. The inner coating shall not contain impurities; 2. There shall be no obvious oil or other impurities in the can; 3. There shall be no pinholes in the can; 4. The can body shall not have any bends or dents that may damage the inner coating; 5. The flange shall be completely flanged, without defects or dents, cracks, burrs, wrinkles, etc. 6. There shall be no damage to the inner wall of the can that exposes metal. For damage suspected of exposing metal, the conductivity value shall meet the requirements. |
A |
S-4 | 0.65 | 500000 Above |
80 80 |
13 3 4 |
| Appearance |
7. The inner coating should not have obvious bubbles, browning, scratches, spots, drops, accumulation, etc.; 8. The inner coating at the bottom should not have bubbles larger than 2mm, and the bottom should not be deformed; 9. The can body should not have dents larger than 1cm2, and the number of dents smaller than 1cm2 should not exceed 2 in the same field of view, and the total number should not exceed 3, and the inner coating should not be damaged; 10. There are no wrinkles at the necking. |
B |
S-4 | 2.5 | 500000 Above |
80 80 |
3 6 9 10 |
| Appearance |
11. The inner coating should have no spots; 12. The printing color and varnish are complete and without serious scratches; 13. There are no small scratches on the outer surface that expose the metal; 14. There are no serious folds on the necking and no serious damage to the bottom metal. |
C |
S-4 | 4.0 | 500000 Above |
80 80 |
5 9 12 13 |
| Printing |
1. The text, pattern and layout shall not be blurred and shall be consistent with the standard physical sample; 2. Empty cans of other trademarks or specifications shall not be mixed; 3. The color shall be consistent with the standard physical sample; 4. There shall be no obvious ghosting (Note 2); 5. There shall be no leakage of white primer on the bottom of the can. |
A | S-1 | 0.65 | 500000 Above | 20 | 0 1 |
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6. The main pattern shall not be damaged, and the pattern of the secondary part shall not have more than 3 minor scratches; 7. The misalignment of the printed pattern shall be less than 1mm; 8. The horizontal overlap width of the plate seam shall be 1.0~3.0mm, and the vertical overlap misalignment of the plate seam shall be ≤1.0mm. |
C |
S-4 | 4.0 | 500000 and above |
80 80 |
5 9 12 13 |
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| Dimensions |
1. Can height: 146±0.3mm, the range of the same batch of products does not exceed 0.50mm; 2. Flanging width: 2.10±0.25mm, the range of the same batch of products does not exceed 0.3mm; 3. Neck inner diameter: 52.40±0.25mm. |
C |
S-3 | 4.0 | 500000 and above |
32 32 |
15 6 7 |
| Conductivity | Average value ≤5mA, maximum value ≤25mA. |
A |
S-4 | 0.65 | 500000 and above |
80 80 |
23 3 4 |
| Water boiling test |
The inner coating film is immersed in distilled water at 68℃±2℃ and kept at constant temperature for 30min. 1. The inner coating should be free of defects such as whitening, blistering, and peeling; 2. The outer coating should be free of defects such as loss of gloss, whitening, blistering, and peeling; 3. The printing color should not fade; 4. The coating at the curling edge should not peel off; 5. Smell the water and the can, there should be no peculiar smell, taste it to confirm that there is no peculiar smell if necessary. |
A | S-1 | 0.65 | 500000 Above | 20 | 0 1 |
| Acid resistance test of inner coating | The inner coating is immersed in 2% (m/V) citric acid solution and steamed at 68℃±2℃×30min. There should be no undesirable phenomena such as whitening, blistering, peeling, and acid spots. | A | S-1 | 1.0 | 500000 Above | 13 | 0 1 |
| Conductivity value | Maximum value ≤25mA, average value ≤5mA. | A | S-1 | 0.65 | 500000 Above | 20 | 0 1 |
| Barcode | Appearance: Can be correctly read, and the numbers, fonts, font sizes, and magnification factors are consistent with the standard physical sample. | A | S-1 | 2.5 | 500000 Above | 5 | 0 1 |
Note 1: When the batch quantity is less than the sample quantity, the batch of materials should be fully inspected. For batches within the batch range of 500000, the batch range should be sampled and judged in accordance with the requirements of batch ranges above 500000.
Note 2: There are two types of ghosting: light and dark. Dark ghosting is mainly manifested as the ink color of some lighter parts in large-area graphic printing is not solid. Bright ghosting is mostly manifested as part of the pattern of dark-colored graphics mixed in light-colored graphics, and the depth and amount vary, sometimes appearing and sometimes not.
Testing frequency: randomly select at least one can from each pallet in each batch, and select the required number in total;
Conductivity test: use an internal coating integrity tester with an accuracy of not less than 0.1mA and a working voltage of 6.3V (DC), connect the can body to the positive electrode, add 1% (m/V) sodium chloride aqueous solution to the can body, with the liquid level 3mm from the can mouth, insert a stainless steel rod to connect the negative electrode, and read the internal coating defect current value of the 4S.
Barcode detection: scan with a barcode reader.
Appearance: Automatically scan with a barcode reader and check the numbers, fonts, and font sizes with the standard sample. They should be correctly readable, and the numbers, fonts, font sizes, and magnification factors should be consistent with the standard physical sample;
Size: Measure with a digital caliper with an accuracy of 0.01mm. The can height and flange height are measured to test 3 uniform points on each empty can.
Internal coating acid resistance test: weigh 20.00g citric acid (C6H807·H20) or 18.29g anhydrous citric acid (C6H807), dissolve in distilled water, dilute to 1000ml, shake well to make 20g/L citric acid solution, pour it into the neck of the test sample tank, seal it and place it upright, steam at 68℃±2℃×30min or sterilize it according to the normal process, take out the sample and accelerate cooling with cold water, open the lid, let the sample tank dry naturally, and visually inspect; or directly immerse the internal coating of the tank in 68℃±2℃×30mins citric acid solution, take out the sample and accelerate cooling with cold water, let the sample tank dry naturally, and visually inspect;
Boiling test: the can body is directly immersed in 68℃±2℃×30min for steaming or sterilized according to the normal process. After steaming, take out the sample and accelerate cooling with cold water, let the sample can dry naturally, and visually inspect;
Other indicators: appearance, printing inspection method, size inspection: according to GB/T9106.1-2009 "Packaging container aluminum easy-open lid aluminum two-piece can".
| Item | Quality requirement | Inspection method |
| Transport vehicle | Should be clean, free of oil and odor. It should not be transported with chemicals, toxic and harmful substances, and items that affect the quality of our factory's products; | Sensory |
| Packaging quality |
1. The pallet is strong, the outer packaging carton is not damaged, and the strapping should be intact; 2. The certificate of conformity is complete, and the model, manufacturer, quantity, production batch number, thickness, production line, inner coating/sealant manufacturer and model, shelf life, etc. of the easy-open lid should be indicated. The side with the certificate of conformity should be facing outward when loading.
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Natural light visual inspection |
| Appearance quality |
1. The cap shape should be intact, and the hook edge should not be obviously deformed; the cap surface should be clean and flat, with basically uniform color, no odor, and no stains; 2. The expansion ring pattern should be clear and consistent in depth; the easy-open cap notch line should not be damaged; the pull ring surface should be smooth, correctly positioned, and firmly riveted; 3. The sealant should have good viscosity and elasticity, be evenly applied, without broken glue, damage, glue accumulation, tailing, overflow, splashing glue, and no obvious bubbles (no obvious bubbles are allowed on the glue surface, and no more than 3 bubbles within 0.5mm without skin breakage in the hook seam) and defects such as scorching and aging; (see the attached table for outer diameter size and glue quantity), the difference in glue quantity detected by the quartering method is less than 5.0mg. 4. Dry mass of sealing glue, 200#: 20-35g, 202# 20-40g. 5. The sealant should not have obvious visible impurities. A. Dense powder or impurities in the sealant are not allowed to appear; B. No more than 2 single granular impurities (≦0.5mm) are allowed in the sealant; C. Obvious visible foreign impurities (black powder or other foreign impurities falling on the sealant surface due to edge scratches) are not allowed. 6. There should be no feathering after opening, and it should be easy to pull open. The pull ring should not be broken or the opening should not be poor. The feathering width is less than 1.5mm, and the 1.5mm-2.0mm width should not be greater than 10%. 2.0mm and above are unqualified. |
Natural light visual inspection； Magnifying glass visual inspection； Analytical balance Vernier caliper |
| Internal coating integrity test |
1. No aluminum exposure after immersion in 20% CuSO4 and 10% HCL solution for 2 minutes (temporary use). 2. Use the internal coating integrity tester and test with 1% (m/v) sodium chloride solution to read the internal coating defect current value at the 4th second. (Standard: single value ≦15, average value ≦8) |
Visual inspection under natural light； Conductivity meter |
| Specifications and dimensions |
1. Outer diameter of groove edge: 59.44±0.25mm; 2. Groove edge height: 2.03±0.15mm; 3. Countersunk degree: 6.86±0.13mm. |
Vernier caliper Depth gauge |
| Curing test | After the curing test of internal and external coating at 121℃ (distilled water at 121℃ for 30min), after cooling and drying, the internal coating has no whitening, peeling, or shedding, the external coating has no obvious loss of gloss, peeling, or shedding, and the printed pattern has no obvious fading. | Visual inspection under natural light |
| Corrosion resistance test | After the corrosion resistance test (using 0.5g/L sodium sulfide (Na2s.9H2O) solution with 3% acetic acid to adjust the pH value to 6.0 at 121℃ for 25min), immediately cool, clean and dry, and observe that the inner coating of the cover has no peeling, shedding, obvious corrosion, bubbles, or whitening. | Natural light visual inspection |
| Sealant boiling test | Boil water (tap water) in a 100℃ water bath for 30 minutes. The sealant should be elastic, without peeling, falling off, or broken bubbles; if bubbles that do not break appear after boiling, they should be able to completely return to their original state after being left for 1 hour. If necessary, it can be first dried in a 100℃ oven for 7 minutes. | Oven, constant temperature water bath, fluorescent lamp, natural light visual inspection |
| Sealing glue moisture | ≦4.0% | Oven test |
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Breaking force Full opening force |
The pull ring does not fall off, it is fully opened, and there is no feathering phenomenon. | Fluorescent lamp, natural light visual inspection |
The can body should have the manufacturer's logo;
The packaging should have a product inspection certificate, which should include the manufacturer's name, product name, product specifications, production batch number (including all traceable information of the supplier), production date, quantity, inspection mark, etc.;
The can body (lid) should be packaged on a pallet, and the packaging material should be clean, dry, and free of falling and pollution hazards;
When packaging on a pallet, the layers should be separated by neutral cardboard or suitable materials, and tied and wrapped with plastic film;
The transport vehicle should be clean and dry, without any odor or pollution. During transportation, it should be protected from rain, sun exposure, moisture, pollution and damage;
