Page 48 - Manufacturing Engineering and Technology - Kalpakjian, Serope : Schmid, Steven R.

26 General Introduction

EXAMPLE l.4 Saltshaker and Pepper Mill
The saltshaker and pepper mill set shown in Fig. l.9
consists of metallic as well as nonmetallic compo-
nents. The main parts (the body) of the set are made
by injection molding of a thermoplastic (Chapter 19),
such as an acrylic, which has both transparency and
other desirable characteristics for this application and
is easy to mold. The round metal top of the saltshaker
is made of sheet metal, has punched holes (Chapter 16),
and is electroplated for improved appearance
(Section 34.9).
The knob on the top of the pepper mill is made
by machining (Chapter 23) and is threaded on the
inside to allow it to be screwed and unscrewed. The
square rod connecting the top portion of the pepper
mill to the two pieces shown at the bottom of the
figure is made by a rolling operation (Chapter 13).
The two grinder components, shown at the bottom of
FIGURE l.9 A saltshaker and pepper mill set. The two
the figure, are made of stainless steel. A design for
metal pieces (at the bottom) for the pepper mill are made by
manufacturing analysis indicated that casting or
powder-metallurgy techniques. Source: Reproduced with
machining the two components would be too costly; permission from Success Stories on P/M Parts, Metal Powder
consequently, it was determined that an appropriate Industries Federation, Princeton, Nj, 1998.
and economical method would be the powder-
metallurgy technique (Chapter 17).

l.1 Computer-integrated Manufacturing

Computer-integrated manufacturing (CIM), as the name suggests, integrates the
software and hardware needed for computer graphics, computer-aided modeling,
and computer-aided design and manufacturing activities, from initial product con-
cept through its production and distribution in the marketplace. This comprehen-
sive and integrated approach began in the 1970s and has been particularly effective
because of its capability of making possible the following tasks:
° Responsiveness to rapid changes in product design modifications and to vary-
ing market demands.
° Better use of materials, machinery, and personnel.
° Reduction in inventory.
° Better control of production and management of the total manufacturing operation.

The following is a brief outline of the various elements in CIM, all described in
detail in Chapters 38 and 39:
I. Computer numerical control (CNC). First implemented in the early 195Os, this
is a method of controlling the movements of machine components by the di-
rect insertion of coded instructions in the form of numerical data.
2. Adaptive control (AC). The processing parameters in an operation are
automatically adjusted to optimize the production rate and product quality