Page 53 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

Section 1.8 Quality Assurance and Total Quality Management

at this level, no modern computer would function reliably. At six sigma, defective
parts are reduced to only 3.4 per million parts made. This level has been reached
through major improvements in manufacturing process capabilities in order to
reduce variability in product quality.
Important developments in quality assurance include the implementation of
experimental design, a technique in which the factors involved in a manufacturing
process and their interactions are studied simultaneously. For example, the variables
affecting dimensional accuracy or surface finish in a machining operation can be
identified readily, thus making it possible for appropriate preventive on-time actions
to be taken.

Quality Standards. Global manufacturing and competitiveness have led to an ob-
vious need for international conformity and consensus in establishing quality con-
trol methods. This need resulted in the establishment of the ISO 9000 standards
series on quality management and quality assurance standards, as well as of the QS
9000 standards (Section 36.6). A company’s registration for these standards, which
is a quality process certijication and not a product certification, means that the com-
pany conforms to consistent practices as specified by its own quality system. ISO
9000 and QS 9000 have permanently influenced the manner in which companies
conduct business in world trade, and they are now the world standard for quality.

Human-factors Engineering. This topic deals with human-machine interactions
and thus is an important aspect of manufacturing operations in a plant, as well as of
products in their normal use. The human-factors approach results in the design and
manufacture of safe products; it emphasizes ergonomics, which is defined as the
study of how a workplace and the machinery and equipment in it can best be de-
signed for comfort, safety, efficiency, and productivity.
Some examples of the need for proper ergonomic considerations are represented
by (a) a mechanism that is difficult to operate manually, causing injury to the worker,
(b) a poorly designed keyboard that causes pain to the user’s hands and arms during
its normal use (known as repetitive stress syndrome), and (c) a control panel on a ma-
chine that is difficult to reach or use safely and comfortably.

Product Liability. Designing and manufacturing safe products is among the essen-
tial aspects of a manufacturer’s responsibilities. All those involved with product
design, manufacture, and marketing must fully recognize the consequences of a
product’s failure, including failure due to forseeable misuse of the product.
As is widely known, a product’s malfunction or failure can cause bodily injury
or even death, as well as financial loss to an individual, to bystanders, or to an organ-
ization. This important topic is referred to as product liability, and the laws governing
it generally vary from state to state and from country to country. Among the numer-
ous examples of products that could involve liability are the following:

° A grinding wheel shatters and blinds a worker.
° A cable supporting a platform snaps, allowing the platform to drop and cause
bodily harm or death.
° Automotive brakes suddenly become inoperative because of the failure of a par-
ticular component of the brake system.
° Production machinery lacks appropriate safety guards.
° Electric and pneumatic tools lack appropriate warnings and instructions for
their safe use.
° Aircraft landing gears fail to descend and lock properly.