KCDS
Key Characteristics Designation System
Most organizations are aware of the need to apply continuous improvement strategies to remain competitive. Similarly there is a growing realization that the success of the final product is largely defined at the early design stages.KCDS is a simple technique that can be used at the early design stage to highlight product characteristics that are critical to quality and to ensure that appropriate actions are taken to achieve optimum outcomes.

Why KCDS?

The integration of computer aided technologies (such as CAD/CAM, Solids Modeling etc) has helped the manufacturing sector achieve unprecedented levels of quality. In this scenario specifications and engineering drawings are used to communicate the designer’s original intent in terms of dimensions and tolerances. But these alone do not define all aspects of quality. Product characteristics such as touch and appearance which customers often associate with good quality are not well covered in this way.
This is a situation that is further exacerbated by outsourcing to foreign suppliers that are not conversant with the levels of quality required by the local customer.

Geometric Dimensioning and Tolerancing (GD&T)

Unfortunately the very dimensioning techniques used in the drawing processes are prone to errors in interpretation. Many leading manufacturers have successfully applied GD&T techniques to help overcome ambiguities that can arise from the incorrect interpretation of engineering drawings. But apart from the added complexity that this can add, many quality features still remain inadequately defined.
KCDS is a simple approach that operates in tandem with GD&T that is aimed at clearly defining all types of characteristics that are critical to quality.

What is KCDS?

Product characteristics that are deemed to be important to the customer require special effort to ensure that the correct design intent is met. The two main designations (KPC’s and PQC’s) are determined by the level of engineering care that is needed to ensure that these are achieved. In some cases this may simply require monitoring to a set dimension, while in other cases it may require a formal continuous improvement program to ensure conformance to a target value.

Quality Loss Function

Most characteristics achieve their results at an optimum target value and as processes drift away from this condition, a noticeable loss in function and quality often results. Simply known as the “Quality Loss Function” this condition is reflected in the graphs shown.

KCC’s and Continuous Improvement

Products and processes that reflect a rapid loss in performance and/or cost as they drift away from their target values are prime candidates for KCDS consideration. In these cases the manufacturers and assemblers must define the key controls (KCC’s) that affect the outcome of the characteristic and develop continuous improvement plans for the reduction in variation and/or the release of designs that are “robust”.

Actions to reduce variation may involve the application of Process Control Plans (PCP’s) and SPC. Actions to make products/processes more robust may involve applying DFMA , Mistake Proofing strategies
and/or Parameter Design principles.

KCDS & FMEA

Provision can be made to integrate KCDS into the FMEA process by flagging the quality features that present a high risk to the customer and applying the standard FMEA procedures to track the application of remedial actions and their results.

For expert consultation, training and facilitation in this field contact:

Lou Travella
Design 4 Excellence
Ph/Fx: 61 3 5221 6413
EMAIL: LTRAVELLA@OPTUSNET.COM.AU