Standards and Quality Practices: Quality Control tools

Introduction:

Any type of device or tool that is used to support the quality of all products.

The 7 quality tools were first conceptualized by Kaoru Ishikawa, a professor of engineering at the University of Tokyo.
They can be used for controlling and managing quality in any organization.

List of The 7 Basic Quality Tools:

The 7 basic quality tools are as follows:

(i) Flow Chart

(ii) Histogram

(iii) Cause-and-Effect Diagram

(iv) Scatter Diagram

(iv) Control Charts

(v) Pareto Charts

(i) Flowchart:

A flowchart is a diagram which represents a workflow process, algorithm, or a step by step process connected by arrows in different directions.

(ii) Check Sheet:

The Check sheet is used to collect data and information in an easy format.
It increases accuracy in the data collection process with easy method and format.

The check sheet is updated by recording “marks” or “checks” on it.

(iii) Cause-Effect Diagram:

Cause-Effect is also known as Fish-bone diagram as the shape is somewhat similar to the side view of a fish skeleton.
Cause-Effect diagram records causes of specific problems or issues related to the processor system. You will get many different causes for a specific problem.

(iv) Pareto Chart:

A Pareto Chart is a Bar graph as well as a Line graph that graphically summarizes the group of data.

(v) Control Charts:

Control charts that are also known as Statistical Process Control are used to determine if the business processes are in a state of control.

(vi) Histogram:

A histogram is a graphical representation in a bar chart that shows pattern falls within different conditions.

It is a distribution of numerical data and it provides necessary information about shape and dispersion or spread of a set of sample data.

(vii) Scatter Diagram:

Scatter Diagram helps to identify the cause and effect in the system and the variable usually represents all possible cause and effect.
Scatter Diagram is also used to identify the correlation between these two variables.

Total Quality Management:

Definition of total quality management (TQM) describes a management approach to long-term success through customer satisfaction.
It is a dynamic process with a strong philosophical base, which incorporates many of concepts upon which total quality control systems are based.

Principles of TQM:

Total Quality Management consist a set of core values and principles on which the organization is to operate.
Total quality management is the continuous management of quality that includes all aspects of an organization.

Taguchi approaches in TQM :

Taguchi proposes a holistic view of quality which relates quality to cost, not just to the manufacturer at the time of production, but to the customer and society as a whole.

Taguchi has developed two methods for quality improvements.

(i) Robust Design

(ii) Taguchi loss function

What is robust design?

Robust design is an “engineering methodology for improving. Productivity during research and development so that high-quality products can be produced quickly and at low cost”.

Your product and service are robust when it performs perfectly to user expectations for its entire design life, even in unpredictable adverse circumstances.

An example of robustness is the McDonalds fast food company.

(ii) Taguchi loss function:

To measure quality, Taguchi defines a Quality Loss Function. The quality loss function is a continuous function that is defined in terms of the deviation of a design parameter from an ideal or target value.

Let, x = the quality characteristic of interest, T = its nominal value then the loss function will be a U-shaped curve

L(x) = C (x – T)²

where x is the critical performance parameter value.

L(x) is the loss associated with a particular parameter x,

T is the nominal value of the parameter specification,

C is a constant that depends on the cost at the specification limits

Quality Function Deployment (QFD):

QFD provides a cross function approach which uses a planned total quality method called "House of Quality” for organizing and linking the customer survey information with the design attributes and later deploying it In stages throughout the organization.