What are the Significant (SC) and Critical characteristics(CC) in Manufacturing & Design Industry?

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Hello,

Today in the industry standard and working culture, Engineers is more confuse with the terms Significant Characteristics (SC) & Critical Characteristics (CC).

So in this post we will look into details about, what is SC & CC Dimensions / Characteristics?

First of all we first see what is Characteristics?

What is Characteristics?

A characteristic is a dimension or a physical, chemical, electrical, mechanical or visual feature of part defined by design data.

Therefore a characteristic must be measurable, either directly or indirectly, and either variable or attribute.

You can learn the what is variable and attribute data by click here.

Attribute characteristics are qualitative data that is checked and results in conformance or non-conformance, pass or fail.

Variable characteristics are quantitative data which can be measured, and the result is an absolute measurement reading e.g. Millimeter, Inch, Kg, Newton, etc.

There are three types of characteristics explain as below:

Key Characteristics

This characteristics is nothing but the dimension of part, material, process or assembly.

So the variation of a Key Characteristics (KC) leads to effect on product fitment, assembly performance, service life or manufacturability of component.

Significant Characteristics

A Significant Characteristics (SC) is also the dimension of part, material, process or assembly.

But it usually observed at lower assembly level.

Therefore achieving the SC characteristics within specification limits leads to get the best final product fitment.

It is very important for next / final assembly part fitment, performance, service life, and/or manufacturability.

Significant Characteristic’s are identify and define in DFMEA and PFMEA and having the relation with the cause and effect of potential failure modes.

In the FMEA, Significant Characteristics (SC) related cause and effect rated as severity 5 to 8, Also if cross function team decide we can rated as less than 5 severity.

The Significant Characteristics (SC) have more effect in manufacturing process. So if the SC characteristics get out of specification limit will leads to produce defects in manufacturing process.

Therefore Manufacturing process needs special controls to maintain the process capability and customer requirements.

Then the next important Characteristics is Critical Characteristics.

Critical Characteristic

A Critical Characteristic (CC) is the dimension / feature of material process, part or assemblies.

The CC Characteristics is mainly given for regulatory requirement (Legal or environmental) purpose.

Therefore, If there is missing or not conforming to design, not as per quality requirement will result to unsafe condition to everyone. And also non compliance with regulatory requirements.

Critical Characteristic’s are identify and define in DFMEA and PFMEA and having the relation with the cause and effect of potential failure modes.

In the FMEA, Critical Characteristics (CC) related cause and effect rated as severity 9-10.

Finally the Critical Characteristics (SC) have more sever effect in manufacturing process. So if the CC characteristics get out of specification limit will leads to produce defects in manufacturing process. As well as company may face a legal issue.

Therefore Manufacturing process needs special controls to maintain the process capability and customer requirements.

Now you know which is Significant & Critical Characteristics, then the final question is where you find these characteristics,

Think

How to find Critical and Significant Characteristics?

These Characteristics mainly mention in drawings by designer / customer.

The Significant Characteristics (SC) mainly mention as Triangle 2 symbol in drawing as below.

Triangle 2

The Critical Characteristics (CC) mainly mention as Triangle 1 symbol in drawing as below.

Triangle 1

Symbolic re-presentation may vary company to company OR different manufacturers use different symbols. You will get these details in their Quality Manuals / CSR’s.

Conclusion:

  • There are important Characteristics as Significant Characteristics (SC) and Critical Characteristics (CC).
  • These characteristics have major impact on manufacturing process.
  • You will need more string control in manufacturing process to control these characteristics.
  • How you find these characteristics in drawing.