The inspection level designates the relative amount of inspection. Three inspection levels, I, II and III, are given in Table A for general use. Unless otherwise specified, level II shall be used. Level I may be used when less discrimination is needed or level III when greater discrimination is required. Four additional special levels, S-1, S-2, S-3 and S-4 are also given in Table A and may be used where relatively small sample sizes are necessary (for example, for some destructive test or time-consuming test) and larger sampling risks can be tolerated.
Sample sizes are designated by sample size code letters and the corresponding AQL level. Table A shall be used to find the applicable code letter for the particular lot size, Table B shall be used to find the sample size based on code letter and the prescribed AQL level.
As default, we uses general inspection level II, Acceptable Quality Level (AQL) Not allowed / 2.5 / 4.0 of Critical, Major, Minor defect.
For example, Consider a shipment of 3,000 units to be inspected. As per single sampling level II, AQL: Not allowed / 2.5 / 4.0 of Critical / Major / Minor:
According to table A, from quantity 1201 to 3200, the corresponding sample size code letter is "K", Then when you check in table B, "K" is corresponding to sample size "125"units.
So the maximum allowed number of defective unit is as follow: Critical Defect 0; Major Defect 7; Minor Defect: 10.
In other words, if the sampling batch of 125 units has more than0 critical defect or 7major defect or more than 10 Minor defects the shipment has to be rejected.
Defects Classification Criteria
Defects detected during inspection are classified within 3 categories -"Critical", " Major ", " Minor "and the normal definitions are:
Critical: Defects which could result in hazardous or unsafe conditions for individuals using or maintaining the product as well as defects contravening legal regulations.
Major: Functional defects reducing the usability or solidity of the product as well as obvious visual defects reducing the sales value of the product.
Minor: Defects that are unlikely to reduce the use of the product, but nevertheless may influence the sale.
For random inspection, the following rules are applied: If the same sample has several defects, only the most serious defect is counted. In the case of critical defects, the entire shipment must be rejected as a matter of principle and clients consulted for a decision.
2. International Standard: ISTA-1A / 2A Carton Drop Test
For the Carton Drop Test, there are 2 standards can be referred, the International Safe Transit Association (ISTA) 1A and 2A. Normally most of clients use the specification of ISTA 1A, the drop procedures of ISTA 1A and 2A are the same, but their Drop Heights are different.
Normally we use the carton drop test standard ISTA1A called the method of "one corner three edges six faces of the carton".
1）Drop Height
The test drop height varies with the weight of the packaged-product:
2） Drop Procedure
a. Firstly, make sure the samples are good samples (Including visual and function).
b. Re-pack it to original condition, including any nylon packing straps if any.
c. Then, select suitable floor. The floor should be flat, rigid base such as steel, concrete etc.
d. Conduct the drop test as per below sequence:
After the drop test, following is not allowed:
- Export cartons are damaged
- Unit boxes inside the export carton are damaged
- Sample or parts inside the gift box are damaged, deformed, scratched, dented or other defects
- The functional performance after the drop check is not satisfactory
Service Standard
Product Inspection
