How do you relate Quality and Reliability?

Thanks Mohamed, that's a good view.
Appreciate your contribution.....
In my view, reliability is measured as the probability or frequency of failure.
How can we relate this to QA or QC? If you have different view of reliability, I would be glad to know.
Its really good to hear from professionals.
Thanks.

Quality showing the Measure of Excellence (means free from defects) and reliability means Consistency.In case of a product its quality means standard of that particular product and its Reliability means producing compatible results time after time.

Quality versus Reliability

• A Quality problem?
• A Reliability problem?
• An Unreliability problem?

Isn't it all about Quality? True, but at the same time that is also the problem. There are so many definitions about quality that is has lead to at least confusion. Quality has to be built into the design, you can not create it during manufacturing. It is very well known that quality is a top-down issue. If the top-down chain does not support quality in actively then no quality will be delivered other than by coincidence. The same is valid for reliability. But one needs to know what it is.

Also quality is too massive to be understood completely by anyone. Quality concerns organizations, management, services, people, procedures, products, life etc. There are many books available, too many maybe.

Relia-Easy limits itself to a specific area , a technical product. It concerns something touchable, a bike, a car, a TV. With products one needs to distinguish between Quality and Reliability.

Quality and Reliability belong together but related to the required activities they belong to different worlds.

Many companies define Quality as "conformance to specifications". Unfortunately this is not true or at least incomplete. There are enough examples known where the product was exactly according to specification but did not satisfy the customers' wishes. And that brings us to a definition of quality I like best.

"Quality is conformance to customer expectations"

That is all. The product may be excellent but if it not according to the expectations of the customer you still have a problem. Specifications (and they can be numerous) are just tools to comply to the expectations of the customers. Also a certain life time belongs to these expectations, depending on the product and the customer. If a car breaks down within10 thousand km then the customer complains, but if it concerns a walking shoe no complaints are heard.

To clear up the differences between quality and reliability Relia-Easy agrees with other specialists who simply state:

• Quality is everything until put into operation (0-hours)
• Reliability is everything happening after0-hours

Quality is today. Reliability is the future. Quality is measurable and controllable. Reliability is crystal ball magic. The only problem is to define the exact moment of0 hours. This depends strongly on the logistics around the creation of a product. Think about suppliers, sub modules etc. The product can be stored in a shop for a long period before it is sold. Spare parts can be on stock for years before they are used. The more complex the product the vaguer the0 hour point. But that is only a technical detail.

Quality is important. Even more important is that this quality should be reproducible. Black belts and six sigma projects play an important role in this area. A lot of literature is available.

Reliability is everything in the future. Crystal ball magic. It is the ultimate challenge to forecast a5 year life period within3 months. Within certain limits and with the right tools this is possible. But it requires a different approach and discipline as in use with quality . In line with the definition for quality reliability is best described as:

"Reliability is quality over time"

Unfortunately a lot of companies focus on the quality aspects until0-hours and during its development barely attention is given to the reliability. Reliability is an essential part of the overall quality but different in approach. Therefore Relia-Easy treats them as two different disciplines.

Quality over time can be called reliability.

Quality is a snapshot at instance of life and reliability is a motion picture of the day-by-day operation.
Time zero defects are manufacturing mistakes that escaped final test.
The additional defects that appear over time are "reliability defects" or reliability fallout.
If you maintain quality through Q.A and Q.C processes, you achieve reliability.

Reliability is an integral part of quality. For achieving the complete quality, reliability must be achieved.

Isn't it all about Quality? True, but at the same time that is also the problem. There are so many definitions about quality that is has lead to at least confusion. Quality has to be built into the design, you can not create it during manufacturing. It is very well known that quality is a top-down issue. If the top-down chain does not support quality in actively then no quality will be delivered other than by coincidence. The same is valid for reliability. But one needs to know what it is.

Also quality is too massive to be understood completely by anyone. Quality concerns organizations, management, services, people, procedures, products, life etc. There are many books available, too many maybe.

Relia-Easy limits itself to a specific area , a technical product. It concerns something touchable, a bike, a car, a TV. With products one needs to distinguish between Quality and Reliability.

Quality and Reliability belong together but related to the required activities they belong to different worlds.

Many companies define Quality as "conformance to specifications". Unfortunately this is not true or at least incomplete. There are enough examples known where the product was exactly according to specification but did not satisfy the customers' wishes. And that brings us to a definition of quality I like best.