FREE online courses on Quality by DesignQuality of Design and Quality of Conformance

 

Creation of any product involves two major stages – intellectual creation and physical creation. During intellectual creation a product is conceived in the mind and a design is created and after that it is physically produced.

 

The term quality involves two complementary aspects, quality of design and quality of conformance. So, good quality can be attained only when both of them are controlled satisfactorily. Quality is designed into a product as much as it is built in during its production or service processes.

 

Quality of design

 

Quality of design is the quality which the producer or supplier is intending to offer to the customer. When the producer is making the quality of design of the product, he should take into consideration the customer's requirements in order to satisfy them with fitness for use of the product.

 

If the quality of design does not reflect the customer's requirements, the product which the producer offers him would not probably satisfy the customer, even if it does sufficiently conform to the design. Quality of design is usually indicated by completeness and correctness of specifications, drawings, catalogues, etc. and is measured with fitness for use.

 

Quality of conformance

 

Quality of conformance is the level of the quality of product actually produced and delivered through the production or service process of the organization as per the specifications or design. When the quality of a product entirely conforms to the specification (design), the quality of conformance is deemed excellent.

 

Specifications are targets and tolerances determined by the designer of a product. Targets are the ideal values for which production is expected to strive; tolerances are acceptable deviations from these ideal values recognizing that it is difficult to meet the exact targets all the time due to variability in material, machine, men and process.

 

For example, if an engineering component manufacturer specifies the diameter of a steel pin as 2.525 + 0.005 mm, the value 2.525 is the target value and  + 0.005 is the tolerance. In a similar way, in case of an Airline service, if on time arrival of a flight is specified as within 15 minutes of scheduled time, the target is scheduled time and tolerance is + 15 minutes.

 

The measure most commonly used for expressing the quality of conformance is fraction defective.  A fraction of defect of 0 % implies that the quality of a product wholly conforms to the quality of design.  Even if the quality of a design is very good and quality of conformance is poor, the product cannot give the intended service and is classified as poor quality product.

 

For example, in case of a service product like maintenance of law and order by governmental agencies, the quality of design is reflected in the relevant acts and rules, whereas quality of conformance depends upon the extent to which these acts and rules are complied by the enforcement agencies. In spite of having excellent rules and regulations, the quality of law and order of society cannot be rated as good, if these rules and regulations are not adhered to properly.

 

Fitness for use (quality of design) and conformance to specification (quality of conformance) provide the fundamental basis for managing the processes to produce quality products. Good quality can be attained only when both, quality of design and quality of conformance are good.