Feature Article : Classifying Quality Defects – Is it Major, Minor or Critical?
By: Jennifer Stepniowski, Special Projects Manager, Pro QC International
In reviewing Pro QC’s blog analytics, it turns out the post getting the most attention concerns the classification of defects noted during inspections. Our readers want to know how we determine whether defects are major, minor or critical. And, how does that affect the result of inspections?
The most important component of product quality is knowing your product. And, that requires detailed product specifications that identify exactly how the item(s) should turn out. What characteristics of the product are required for it to “meet or exceed expectations?”
Product specifications should include defect details with classifications that later link to accept/reject determinations during QC checks. Clients often supply their own product specifications for inspection requirements, but we frequently assist with development as well. In general, the more specific the product criteria is, the less subjective the nature of the defects are.
Defects can be anticipated, but the list should evolve through observation and consumer feedback. Metrics, as always, are incredibly useful here where continuous improvement is concerned.
Each defect noted during an inspection is generally classified as major, minor or critical. At Pro QC, we use the following general descriptions:
Critical – Any condition found which poses the possibility of causing injury or harm to, or otherwise endangering the life or safety of, the end user of the product or others in the immediate vicinity of its use.
An example of a critical defect might be a sharp plastic bur that has potential to scratch or otherwise harm people. The AQL (Acceptable Quality Level) is generally 0 here so any critical defects noted result in a rejected inspection.
Major – Any condition found adversely affecting the product’s marketability and sale-ability or adversely affecting its required form, fit or function and which is likely to result in the end user returning it to the source from which is was purchased for replacement or refund.
An example of a major defect might be a large (1.5″ or larger) scratch on the exterior front of the product. The AQL is generally tighter for major defects noted, so less is acceptable in a general sample size to achieve a passing result.
Minor – Any condition found which while possibly less than desirable to the end user of the product, does not adversely affect its required marketability, sale-ability, form, fit or function and is unlikely to result in its return to the source from which it was purchased.
An example of a minor defect might be a small (up to 1.5″) scratch on the bottom of the product.
Regarding AQLs, Pro QC uses the ANSI Z1.4 2003 tables. For general accept/reject determinations, the default is 1.5 for major defects, 4.0 for minor defects and 0 for critical defects as noted previously. Using an example shipment of 1,000 units and a visual random selection of eighty units (General Level II), only three major defects would be allowed and seven minor for an acceptable result. Special testing, such as functionality, would be treated separately. All components of the inspection must have an “accept” result for a final passing determination.
Inspection reports are posted online within 24 hours of completion. Any defects noted are described in detail. Pro QC provides digital photos, which can be particularly useful. Tracking defects and noting areas for improvement when trends are identified helps improve the overall manufacturing process and end-use value to the consumer.
For additional information regarding the inspection process, contact your account manager or email us at email@example.com.