2. 7.1. QUALITY MANAGEMENT
7.1.1. Introduction
• High-quality products are reliable, dependable, and
satisfying, they do the job they were designed for
and meet customer requirements.
• Managers seek to control and improve the quality of
their organization’s products for two fundamental
Reasons:
1) The first reason for trying to boost product quality is
that higher product can increase efficiency and
thereby lower operating costs and boost profits.
3. Cont.
2. The second reason customers usually prefer a
higher-quality product to a lower-quality product.
7.1.2. Meaning of Quality
The notion of quality has been defined in different
ways by various authors.
Garvin identified a framework of the following eight
attributes that may be used to define quality:
performance, features, reliability, conformance,
durability, serviceability, aesthetics, and perceived
quality.
4. Cont.
• According to Crosby quality is conformance to
requirements or specifications and Juran defined
quality as fitness for use.
• Fitness for use is related to benefits received by the
customer and to customer satisfaction. Only the
customer, not the producer, can determine it
(Schroeder, 2000).
• According to Schroeder (2000), customer
satisfaction is a relative concept that varies from one
customer to another and from time to time given a
specified customer.
5. Cont.
• The implication for production managers is,
therefore, to first identify quality specifications
defined by customers and continuously evaluate and
monitor quality performance of the products they
produce.
6. 7.1.3. Determinants of Quality
• The degree to which a product or a service
successfully satisfies its intended purpose has four
primary determinates.
• These are:
1. Design
2. How well it conforms to the design
3. Ease of use
4. Service after delivery
7. • Design, planned quality
• Intension of designers to include or
exclude features in a product or service
– EX: Designed size, actual durability
– Customer input is accounted for
8. • 2. Conformance to design (standards),
executed quality
• The degree to which goods or services
conform to the intent of the designers
– EX: Actual size, actual durability
– Design for quality: Design with quality in
mind
• 3. Ease of use
– EX: Directions, instructions, training
• 4. Service after delivery
9. 7.1.4. The Costs of Quality
• Internal failure costs
• External failure costs
• Appraisal costs
• Prevention costs
10. • Failure Costs - costs incurred by defective
parts/products or faulty services.
• Internal Failure Costs
– Costs incurred to fix problems that are detected
before the product/service is delivered to the
customer.
• External Failure Costs
– All costs incurred to fix problems that are
detected after the product/service is delivered to
the customer.
11. • Appraisal Costs
– Costs of activities designed to ensure quality
or uncover defects
• Prevention Costs
– All TQ training, TQ planning, customer
assessment, process control, and quality
improvement costs to prevent defects from
occurring
12. 7.1.5. Quality Circles and Quality
Improvement Teams
• A quality circle is a typical informal group of people
that consists of operators, supervisors, managers,
and so on, who get together to improve ways to
make the product or deliver the service.
• The quality improvement team, on the other hand, is
cross-functional in nature and involve people from
various disciplines and organized to identify feasible
solutions to quality problems.
13. 7.1.6. International Quality Documentation
Standards (Documentation Standards)
• ISO 9000
• The purpose of the international organization for
standards (ISO) is to promote worldwide standards
that will improve operating efficiency, improve
productivity and reduce costs.
• ISO 9000 series is a set of international standards
on quality management and quality assurance.
• ISO 9000 certification involves several steps
starting from identification of international quality
standards through certifying the producer.
14. Cont.
• A key requirement for registration is that a company
review, refine, and map functions such as process
control, inspection, purchasing, training, packaging,
and delivery.
• Registered companies face an ongoing series of
audits, and they must be registered every three
years.
•
15. 7.1.7. ISO 14000- An Environmental
Management System
• The ISO 14000 documentation standards require
participating companies to keep track of their raw
materials use and their generation, treatment, and
disposal of hazardous wastes.
• ISO 14000 covers a number of areas,
including the following:
• Environmental Management System
• Environmental Performance Evaluation
• Environmental Labeling
• Life-cycle assessment
16. 7.1.8. Total Quality Management
(TQM)
A philosophy that involves everyone in an organization
in a continual effort to improve quality and achieve
customer satisfaction.
• TQM is a philosophy of perpetual improvement. It is
the foundation for activities which include:
• Meeting customer requirements
• Reducing development cycle times
• Just in time/demand flow manufacturing
• Improvement teams
• Reducing product and service costs
• Improving administrative systems training
17. TQ M has the following main principles:
• Quality can and must be managed.
• Everyone has a customer and is a supplier
• Processes, not people are the problem
• Every employee is responsible for quality
• Problems must be prevented, not just fixed.
• Quality must be measurable and measured
• Quality improvements must be continuous
• The quality standard is defect free
• Goals are based on requirements, not negotiated.
• Life cycle costs, not front end costs.
• Management must be involved and lead
• Plan and organize for quality improvement
18. 7.2.QUALITY CONTROL
• Introduction:
• Quality control may generally be defined as a system
that is used to maintain a desired level of quality in a
product or service.
• This task may be achieved through different
measures such as planning, design use of proper
equipment and procedures, inspection, and taking
corrective action in case a deviation is observed
between the product, service or process output and
a specified standard.
19. 7.2.2. Quality Control and Improvement
• Design of Quality Control Systems:
• Steps:
1.Identification of the process
• All quality control must start with the process
itself.
• A process can be an individual machine, a group
of machines, or any of the many clerical and
administrative processes that exist in the
organization.
• Each of these process has its own internal
customers and its own products or services that
are produced.
20. 2. Identification of the critical control points
• These can be identified where inspection or measurement
should take place.
• The control points can be the inputs, work in process and/or
the outputs of the production system.
3. Deciding on the type of measurement to be used at
each inspection point
• There are two options:
• Measurement based either on variables or on
attributes.
a. Variable measurement: utilizes a continuous
scale by measuring for such factors as length,
height and weights.
21. b. Attribute measurement
• uses a discrete scale by counting the number of
defective items or the number of defects per unit.
4. Deciding on the amount of inspection to use
Sample vs Population inspection
5. Deciding who should do the inspection
Internal vs external auditors
22. Process Quality Control
• Process quality control utilizes inspection (or
testing) of the product or service while it is
being produced.
• Periodic samples of the output of a
production process are taken.
• after inspection of the sample, there is
reason to believe that the process
quality characteristics have changed,
the process is stopped and a search is
made for an assignable cause.
23. Cont.
• This cause could be a change in the operator, the
machine, or the material.
• When the cause has been found and corrected, the
process is started again.
• A process can be brought to a state of control and
can be maintained in this state through the use of
quality control charts/also called process charts/ as
shown below:
24. Cont…
• Statistical process control methods extend the
use of descriptive statistics to monitor the quality
of the product and process.
• Using statistical process control, we want to
determine the amount of variation that is
common or normal.
• we want to make sure the process is in a state of
control.
• The most commonly used tool for monitoring the
production process is a control chart.
25. Developing Control Charts
• A control chart (also called process chart or
quality control chart) is a graph that shows
whether a sample of data falls within the
common or normal range of variation.
• A control chart has upper and lower control limits
that separate common from assignable causes
of variation.
• We say that a process is out of control when a
plot of data reveals that one or more samples fall
outside the control limits.
27. Types of Quality Control Charts
I. For Variables
When variable measurement is used, two control
charts are needed: one for the central tendency, and the
other for variability of the process.
Measures of such quality characteristics are assumed
to form a normal distribution and hence, have two
parameters, mean and variance.
Measures of such quality characteristics have to be
evaluated using both parameters.
28. Mean Charts and Range charts
Steps:
• Determine the sample size to inspect
• Determine the number of times you are to take the
predetermined sample size
• Conduct the inspection by measuring the quality characteristic
for each unit in the sample
• Calculate the average and range of quality characteristic
measures for each sample
• Calculate the grand average: central line for both parameters
• Calculate the Upper and lower control limits for both
parameters
•
38. 2. FOR ATTRIBUTES
• Control charts for attributes are used to
measure quality characteristics that are
counted rather than measured.
• Attributes are discrete in nature and entail
simple yes-or-no decisions.
39. i. P-Chart
• P-charts are used to measure the
proportion of items in a sample that are
defective.
• P-charts are appropriate when both the
number of defectives counted and the
size of the total sample can be counted.
• A proportion can then be computed and
used as the statistic of measurement.
