What are the common misunderstandings about food can sealing tests?

1. Misunderstandings in selecting test methods
1. Dangers of positive pressure testing:
Misunderstanding: Some companies use positive pressure sealing testers to inflate the can and observe whether there is leakage within 60 seconds. This method has huge risks, especially when testing unqualified products, which may cause the can to explode, causing personal injury and equipment damage.
Improvement suggestions: For positive pressure testing, local testing instruments should be selected, such as the ZY-30 series positive pressure leakage tester, which tests by locally cutting the sealing part, avoiding the risk of explosion and improving the test accuracy.
2. Limitations of vacuum testing:
Misunderstanding: Although vacuum testing can detect obvious leaks, it has limited detection capabilities for tiny leaks. For example, some packages will leak under a negative pressure of -55.5 kPa.
Improvement suggestions: Use a sealing tester with a gradient test function, such as LEAK-02, which can set different pressure gradients to detect the sealing performance of each pressure point at one time and improve detection efficiency.
2. Misunderstandings of test environment and conditions
1. Ignoring environmental impact:
Misunderstanding: Many companies do not fully consider the impact of environmental conditions on sealing performance during testing. For example, environmental factors such as temperature and humidity may cause deformation or corrosion of the can body, thereby reducing the sealing performance.
Improvement suggestions: Before testing, ensure that the temperature and humidity of the test environment meet the standard requirements, and record the environmental conditions in the test report for traceability and analysis.
2. Testing issues of low-temperature storage products:
Misunderstanding: For products that require low-temperature storage, the impact of temperature changes on sealing is not considered during testing. For example, rapid temperature changes may cause large-sized leaks to go undetected.
Improvement suggestions: When testing low-temperature storage products, ensure that the test environment temperature is stable, and let the product return to room temperature before testing to avoid misjudgment due to temperature differences.
3. Misunderstandings in interpreting test results
1. Misjudgment of leakage type:
Misunderstanding: During the test, physical expansion cans may be misjudged as chemical or bacterial expansion cans. Physical expansion cans are caused by excessive cooling after sterilization. The contents have not deteriorated, but consumers often cannot distinguish them, leading to misjudgment.
Improvement suggestions: Record the type of bulging cans in detail in the test report, and mark the physical bulging cans to avoid consumer misjudgment. At the same time, strengthen the cooling control during the production process to reduce the occurrence of physical bulging cans.
2. Ignore small leaks:
Misconception: During the test process, the impact of small leaks may be ignored. For example, some test methods cannot detect leaks with micron-level apertures, resulting in product deterioration in actual use.
Improvement suggestions: Choose high-precision test equipment, such as gas permeation testers, which can detect small leaks and ensure the sealing performance of the product.
IV. Misconceptions in the selection of test equipment
1. Equipment applicability issues:
Misconception: The test equipment selected by some companies is not suitable for specific types of food cans. For example, some equipment can only detect transparent packaging, while food cans are often opaque.
Improvement suggestions: When selecting test equipment, choose the appropriate equipment according to the material and shape of the food can. For example, for opaque metal cans, choose detection equipment that can penetrate the can body.
2. Equipment accuracy issues:
Misconception: The test equipment used by some companies is not accurate enough, resulting in inaccurate test results. For example, some equipment cannot distinguish leaks of different sizes.
Improvement suggestions: Select high-precision test equipment and calibrate the equipment regularly to ensure the accuracy of the test results.
V. Test operation misunderstandings
1. Improper operation:
Misunderstanding: Improper test operation, such as failure to strictly follow the standard operation during the test, resulting in inaccurate test results.
Improvement suggestions: Develop detailed operating procedures and train testers to ensure the standardization of test operations.
2. Insufficient test time:
Misunderstanding: The test time is too short to detect potential leaks. For example, some test methods require 60 seconds at a specific pressure, but the actual operation may not be enough time.
Improvement suggestions: Strictly follow the test time required by the standard to ensure the reliability of the test results.