Process Stabilization

In the ideal situation, the output of a process is ‘zero defect’: this means whatever happens, all output is either within the specification, or there is no output at all.

What are the conditions to achieve this?

1. The output needs to be clearly defined:

Proces

Output

Spec A Spec B Spec C

     All specifications are known and controlled. (This sounds completely logical however I am astonished how often even the basic specifications are either undefined, wrongly defined, unknown, invisible or non-traceable!)

Proces

Conditions (Fixed)

In the process, all conditions to achieve a proper conversion are known and it is possible to maintain those conditions at any moment:

Proces

Steering Parameter

The process has one (or very few) steering parameters:

If the process needs to be directed, adjusted or otherwise regulated, there is only ‘one knob to turn’

Spec Input A

Spec Input B

Proces

The process has one or more inputs, all within spec;

Output

Spec Input A

Spec Input B

Proces

Steering Parameter

Spec A Spec B Spec C

Conditions

Concluding: In the ideal situation, for each different output:

1. All input is clearly specified and always within spec.
   1. All conditions are clearly specified and maintained from first till last output.
   1. The process is regulated/steered with one (or just very few) parameters.
   1. As soon as one of the above parameters is out of spec, the process is being stopped and no of-spec product will be produced.
   1. As long as all parameters above are being met, the output is 100% in spec.

Process Control Principles

1. What input needs to be present in order to run the process?

What are the specifications of this input?

What conditions need to be fulfilled to run the process in a safe and controlled manner?

Define:

What parameters influence the process?

What parameters need to be fixed at what value?

What parameter can be used to steer the process?

What is the desired output of the process

Define the specifications (including limits) of the output

The process needs to be stopped when:

• Conditions input are out of spec
• Fixed parameters are out of spec
• Steering parameter can no longer regulate output.