1.Microsensors (sensor)
Previous
answer
Microsensors are definied as tiny detectors typically
manufactured by microfabrication processes,included in this definition are
small detectors creating using wire electrodes and the like. Most of this kind
of sensors have been fabricated using microelectronic process technology.The
commercial potential of these devices depends upon their characteristics and
their state of development.
(National Research Council,Human Exposure Assessment
for Airbone Pollutants,p. 99)
New
answer (better)
Microsensors. A sensor is a device that detects or
measures some physical phenomenon such as heat or pressure. It includes a
transducer that converts one form of physical variable into another form (e.g.,
a piezoelectric device converts mechanical force into electrical current) plus
the physical packaging and external connections. Most microsensors are
fabricated on a silicon substrate using the same processing technologies as those
used for integrated circuits (Chapter 34). Microscopic-sized sensors have been developed
for measuring force, pressure, position, speed, acceleration, temperature, flow,
and a variety of optical, chemical, environmental, and biological variables.
The term hybrid microsensor is often used when the sensing element (transducer)
is combined with electronic components in the same device. Figure 36.2 shows a micrograph
of a micro-accelerometer developed at Motorola Co.
(Groover, M.P.,
Fundamentals Modern Manufacturing: Materials, processes and systems 4th
Edition, pp. 854)
2.Plasticizer (chemical)
Prewious
answer
A plasticizer is a substance, which is incorporated
into a plastic or a coating to increase flexibility, workability or
distensibility. This is achieved by loosening the strength of intermolecular
forces resulting in a higher flexibility of macromolecules or segments of
macromolecules (Brownian motion). A plasticizer thus may reduce the melt
viscosity and lower the temperature of the second order transition or glass
transition temperature, Tg, of the product. Plasticizers are inert, organic substances
with low vapour pressures, predominantly esters.
(Eyerer P., Weller M., Hübner C., Agnelli J.A., The
handbook of environmental chemistry: polymers - opportunities and risks II:
sustainability, product design and processing, 2010, pg.120)
New
answer (better)
Plasticizers are chemicals added to a polymer to make
it softer and more flexible, and to improve its flow characteristics during
forming. The plasticizer works by reducing the glass transition temperature to
below room temperature. Whereas the polymer is hard and brittle below Tg, it is
soft and tough above it. Addition of a plasticizer1 to polyvinylchloride(PVC)
is a good example; depending on the proportion of plasticizer in the mix, PVC
can be obtained in a range of properties, from rigid and brittle to flexible
and rubbery.
(Groover M.P., Fundamentals
of Modern Manufacturing: Materials, Processes and Systems 4th Edition, pp.
164)
3.Lancing (shaping)
Previous
answer
Lancing is a combined cutting and bending or cutting
and forming operation performed in one step to partially separate the metal
from the sheet. Among other applications, lancing is used to make fouvers in sheet
metal for venting of heat from the interiors of electrical cabinets.
(Mikell P. Groover,Fundamentals of Modern
Manufacturing,4th Edition,pg.460)
New
Answer (better)
lancing - is a sheet metal operation that makes a slit
or cut that is not long enough to produce a separate piece. No scrap is
produced because the cut does not extend from edge to edge. The usual purpose
is to facilitate a subsequent forming operation on the workpiece by allowing
the material to flow more easily. A workpiece with this kind of cut is
illustrated in Fig. 2C8.
(Bralla, J. G., Handbook
Manufacturing Processes, How Products, Components and Materials Are Made, pp.46)
4.Limited Sequence
Control
Previous answer
This
control system is intended for simple motion cycles, such as "pick-and-place"
applications. It does not require a microprocessor and can usually be implemented
using limit switches and mechanical stops, together with a sequencer to
coordinate and time the actuation of the joints. Robots that use limited
sequence control are often pneumatically actuated.
(Mikell P.
Groover,Fundamentals of Modern Manufacturing,3rd Edition,pg.903)
New answer (better)
This is the
most elementary control type. It can be utilized only for simple motion cycles,
such as pick-and-place operations [i.e., picking an object up at one location
and placing it at another location). It is usually implemented by setting limits
or mechanical stops for each joint and sequencing the actuation of the joints
to accomplish the cycle. Feedback loops are sometimes used to indicate that the
particular joint actuation has been accomplished so that the next step in the sequence
can be However. there is no servo-control to accomplish precise positioning of
the joint. Many pneumatically driven robots are limited sequence robots.
(Groover,
M. P., Automation,Production Systems and
CIM, pp.218-219)
5.Slotting method (shaping)
Previous
answer
A slotter is mainly used for internal machining of
blind holes or vertical machining of complicated shapes which are difficult to
be produced on horizontal shaper. Jobs such as keyway cutting, machining of
square holes, cutting of internal or external teeth on bigger gears and
machining of dies, straight or curved slots are taken up on this machine. Main parts of a slotter are base (or bed),
column, saddle, cross slide, table and ram and tool --head.
(Kaushish J.P., Manufacturing Processes, Second
Edition, p.487-488)
New
answer (better)
This process is essentially the same as shaping except
that the movement of the cutter is most often vertical, and the process is
usually used to make a keyway or other slot in the part, rather than a flat or contoured
surface. Gear shapers are special machines similar to slotters, used for
machining spur and helical gears.
(Bralla, J. G., Handbook
Manufacturing Processes, How Products, Components and Materials Are Made, pp.
115,135)
The slotter or slotting machine is also a
reciprocating type of machine tool similar to a shaper or a planer. It may be
considered as a vertical shaper. The chief difference between a shaper and a
slotter is the direction of the cutting action. The machine operates in a manner
similar to the shaper, however, the tool moves vertically rather than in a
horizontal direction. The job is held stationary. The slotter has a vertical
ram and a hand or power operated rotary table.
(Singh, R., Introduction
to Basic Manufacturing Processes and Workshop Technology, pp. 444)
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