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4 Definition of Quality

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4.1 Base
Producing ‘quality’ means:
Producing a product that meets ALL specifications, not by trying more than once but First Time Right.
4.2 Specifications
  • Specifications with a fixed value (no specification-range) have zero tolerance against that value. So [0=0] and [55=55.00000].
  • Specifications within a range allow a natural variance (or standard deviation) within those limits (>= 1,25 and <= 1,5)
  • All standard deviations brought together in ANY combination will still produce a correct end-result
4.3 B-Quality
Products not meeting its full spec, but still useful and possible to sell (i.e. as B-brand, or in a different market) are ‘not first time right’ and thus should be considered ‘scrap’.
4.4 Rework
If a product does not meet its spec, but can be reworked, it is in terms of OEE to be considered as ‘scrap’. It can be identified as a special form of scrap, by labeling it as ‘rework’.
Rework and scrap will require different handling and have a different cost.
In terms of OEE, Scrap, rework and sub-spec are the same: It was ‘not first time right’; therefore it is a loss
4.5 Principles
The following principles apply generally to process-design and should be considered carefully when applying and defining OEE at the core of your process: the actual physical value-creation.
These principles are to be seen as a set; they cannot be separated.
  • Data is collected as near at the source as possible
  • Who enters the date is owner
  • Who owns the data enters it
  • Who owns the data is responsible for its correctness
  • Who guarantees, is allowed to set requirements
  • Who performs a task guarantees its quality
  • Who cannot guarantee the quality of its output is obligated to stop the process
  • Who detects a downstream failure, returns it to the previous step without correction
  • Who makes a mistake solves it
  • It is allowed to make a mistake ónce, in order to prevent it from ever re-occurring
  • The management guarantees a system that allows the employees to perform its task within spec
4.6 Remarks
  • Defining scrap-product definitions may reveal poor specifications or poorly testable specifications!
  • Good specifications always refer to the needs of the customer!
  • We can only ask the operator to produce quality when he is able to check the quality of his labor!
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