Definition(s) of QUALITY

Is the produced OUTPUT meeting its specifications - Where did we lost PRODUCT?


A machine should only produce product that fully meet its specifications.


When the output does not meet the spec:

When and What reject did occur?

What is


Quality in OEE means: meeting the Specifications

The definition of Quality within OEE is a simple one:

Producing a product that meets ALL specifications,

not by trying more than once but First Time Right.


'Specifications' determine 'Quality'

Although the introduction of OEE typically may lead to discussions about the used specifications (which is highly valuable!), OEE -by definition- takes the applied specifications as a given. They are being met or not.

Check your specifications at least for the following characteristics:

Fixed Values

Specifications with a fixed value (no specification-range) have zero tolerance against that value. So [0=0] and [55=55.00000].

Specification Range

Specifications within a range allow a natural variance (or standard deviation) within those limits (>= 1,25 and <= 1,5). Check the correctness, meaningfulness and feasibility of the range as it if often not correct.

Combined standard deviations

 The rule is:

All standard deviations brought together in ANY combination

will still produce a correct end-result.

Make sure your quality-specifications meet this rule to prevent sub-optimal settings.


In terms of OEE, Scrap, Rework and Sub-spec are the same:

It was ‘not first time right’;

therefore it is a loss

  • Without applying strict criteria, process control can not be achieved.

Who can afford to have (quality)losses,

can certainly afford to eliminate them


Quality is (far) more than a set of papers...

  • 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!
  • Who performs a task guarantees its quality
  • Who guarantees, is allowed to set requirements
  • 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 its specifications


The standard is the theoretical maximum speed for a product(group) on the machine;

thus the performance rate never exceeds 100%

This means:

100% OEE =

The theoretical maximum capacity of the equipment

And thus it can NEVER be more, so:

At well-chosen Standards, the performance rate will NEVER exceed 100%,

unless the product or the machine fundamentally changes

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