College of Production Technology

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Chris Greenwood – MD, College of Production Technology (CPT)

Design involves decisions about the specific characteristics of a product or service such as size, shape, and location. Quality of design refers to the intention of designers to include or exclude certain features in a product or service. In short, you must



A poor design can result in difficulties in production or service.

For example, materials might be difficult to obtain, specifications difficult to meet, or procedures difficult to follow.

Moreover, if a design is inadequate or inappropriate for the circumstances, the best workmanship in the world may not be enough to achieve the desired quality

It is not unusual to find that the customer, himself is not always certain of what he requires. He may express, clearly, the primary functional parameters he requires, but, beyond these, it is up to the designer to extract more information by negotiating on possible additional features and alternatives. And so, the “snowball” grows even larger.

Quality of design is the intrinsic or inherent quality of the product. If the design is not to standard there is a strong possibility, in volume production, that all the items produced could be unacceptable. It is therefore vitally important that the design be reviewed and qualified before production starts. On a “one-shot” project, like a construction, this is even more important.

Within the framework of the customer’s requirements, there are six main parameters of design quality that must be considered by the designer and the design review team:

CAPABILITY: The ability of the product to function according to requirements and to meet the safety and sensory standards specified.

  • RELIABILITY: The probability that a product will perform its intended function safely, for a stated period under stated conditions.
  • MAINTAINABILITY: The probability that, in the event of failure, a product will be restored to full functional state within a specified time under stated conditions.
  • AVAILABILITY: The ratio of “up-time” to the sum of “up-time” plus “down-time”, normally calculated as an average. It is therefore a function of reliability and maintainability.
  • PRODUCIBILITY: The ease with which the product can be produced, fabricated / assembled or erected.
  • FLEXIBILITY: The ease with which the design or the product lends itself to modifications and changes, with a minimum of technical difficulties and costs.

Again, we see the necessity for establishing, with the customer clear specifications and requirements for each of these parameters as early as possible. One cannot over emphasise the need for customer-supplier relations in defining “quality”.

At the College of Production Technology (CPT), we offer Quality Assurance training as a Registered Skills Programme or as a Workshop. Please contact CPT on 0860 278 278 or info@cpt.co.za for more information.


At the College of Production Technology (CPT), we offer Quality Assurance training as a Registered Skills Programme or as a Workshop. Please contact CPT on 0860 278 278 or info@cpt.co.za for more information.

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