Given the recent developments in quality as a partnership and continual improvement, the concept of zero defects might be given a different look. If you consider the definitions of defect and nonconformity it could possibly be applied.
Defect: - a departure of a quality characteristic from its intended level or state that occurs with a severity sufficient to cause an associated product or service to not satisfy intended, normal or reasonable foreseeable usage requirements. (Armand V. Feigenbaum – Total Quality Control 3rd Edition Revised)
Nonconformity: - a departure of a quality characteristic from its intended level or state that occurs with a severity sufficient to cause an associated product or service to not meet a specification requirement. (Armand V. Feigenbaum – Total Quality Control 3rd Edition Revised)
The concept of “Zero Defects” now becomes a commitment to not supply any product which would cause an associated product not to satisfy intended, normal or reasonable foreseeable usage requirements. This is certainly achievable within the statistical boundaries set by a stable process. A nonconformance to this commitment can be classed as a “Gross Nonconformance”.
Now quality becomes a true partnership. Assuming a capable and stable process, the supplier has committed to not supplying a “Gross Nonconformance” while continuing to improve the process by reducing minor nonconformance. The customer, now confident of “Zero Defects”, accepts and uses product supplied under a normal capable and stable process knowing any minor nonconformance which may statistically be present will not be detrimental to his product.
Obviously, in addition to the supplier/customer partnership, the definition of “Gross Nonconformance” is critical to satisfactory implementation of this “Zero Defects” concept. It could be stated that any nonconformance undetectable to the customer through subsequent testing or use could be called “minor”. Anything the customer could detect would then be classed “Gross”. This may not, in all circumstances, consider the “usage” requirement identified earlier.
The preferred method would be to define “Gross” at the
APQP stage. Each part controlled and monitored with its own criteria. Minor nonconformance would be brought to the attention of the customer and a mutual agreement to “usability” would be made.
Given the right elements of partnership, planning, communication and process stability, it would seem possible to reach a plateau of “Zero Defects”.
Just my opinion but it is what I am preaching to our company.
Dave
