100-Metodos-de-Qualidade-Total

MANAGEMENT METHODS
Method 1
Acceptable quality level (AQL)
Purpose
To provide a structure of sampling plans, risks and inspection strategies to
ensure that the customer receives the quality that the supplier has
contracted to deliver.
When to use
When sampling by attributes, so that each item inspected is classified as
acceptable or unacceptable. AQL can be used for 'defective units', where
the whole unit is classified as defective (e.g. incorrect forms or faulty
bottles); or for 'defects', (e.g. errors on invoices or marks on paintwork).
How to use
Before any batch of work is sampled, it is essential to have certain specified
information about the quality standards to be met, together with background
information about the particular batch of work to be sampled.
Specific information is:
1 The agreed acceptable quality level (AQL). This is defined as the worst
quality which can be considered acceptable as the average 'per cent
defectives' or 'defects per 100 units' of a process. AQLs are agreed
between the supplier and external customer or between internal
suppliers and customers. AQLs range from 0.0100 to 1,000 defects per
1,000 units and are given in BS 6001 .
2 The inspection level. This allows some latitude in sample sizes. There
are three inspection levels: normal; tightened; and reduced. An AQL is
the borderline between acceptable and unacceptable quality. When an
AQL has been agreed, the ideal situation is to have all batches better
than the AQL accepted and all those worse rejected. Since this is
impossible, AQLs use something called an 'operating characteristic
curve' which tells you the risks that you are taking and effectively
allows the level of risk to be chosen to reHect your knowledge of the
current situation and what is important to you.
• Normal inspection is designed to protect the supplier against a high
level of rejection. In effect, the supplier is given the benefit of any
doubt. The customer receives protection from a set of rules that allow