Chapter 36 - Quality Assurance

Craft Production Model

Items used to be produced by one person and at a really high quality, but also at a very high price

Mass Production Model

Production became not an individual's job, but a team. Quality became it's own department and not just part of the entire process.

Walter Shewhart

Applied statistics to quality

Quality

Form, fit, and function of a product. Product's fitness for use.

Quality terms

Quantifiable:

- surface finish

- hardness

- size

- size

- weight

Qualifiable:

- color

- feel

- difficulty level

Specifications

Specific guidelines that a manufacturer is required to meet for a product in order to conform to a customer's quality requirement

Quality Assurance

Systems to ensure that products conform to a detailed set of specifications

Sets up a system that analyzes and addresses defects

Quality Control

Techniques to fulfill quality requirements

Methods of detecting changes in a process

Total Quality Management (TQM)

company wide policy to produce high quality

focus is on defect prevention and not detection

emphasizes controlling process as opposed to control of the parts

reducing process variability

Quality Circles

teams of employees on various levels that address quality issues

W.E. Deming

American born statistician that recognized the inherent variability in manufacturing processes

Helped Japan rebuild economy after WWII

J.M. Juran

Electrical Engineer, consultant and a contemporary of Deming

- emphasized quality at all levels of an organization

- deep belief in training

- recognized the conflicting goals of top management and quality assurance/control

Juran Trilogy

Quality Improvement

Quality Planning

Quality Control

G. Taguchi

Engineer and statistician, believed that high quality and low cost was best achieved by combining engineering with statistical techniques to optimize design and manufacturing processes

Cost of Poor Quality

Dissatisfied customers

service and repair cost

loss of credibility

loss of market share

Cross Functional Teams

The whole organization participates

Experimental Design

Studying the variables of the process

Robust

The design, process, or system continues to function despite variabilities to the process. Minimal sensitivity to input variations

Taguchi loss function

Tool that studies how a product changes in terms of function (quality) as the component deviates from design objectives

All the figures of quality emphasized...

The whole company has to embrace quality

Quality starts before manufacturing

High quality ultimately lowers cost (long term)

Statistics could be used to control the process

Special (Chance) Causes

Random events of no trends or patterns

Assignable (common) Causes

Traced to a specific change or event

Control Charts

Method of displaying the variations of a process and detecting special cause variation

Control limits

Limits on the probability of creating a certain dimension