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TERM
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DEFINITION
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| ABS |
acrylonitrile/butadiene/styrene (an amorphous copolymer) |
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| amorphous |
without (regular) form, glassy, noncrystalline, a condition of great
disorder or absence of structure |
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| anisotropy |
condition in which properties depend on direction (i.e., properties
are different in different directions) |
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| catalysis |
acceleration of a chemical reaction by catalysts |
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| cavity |
specially shaped open space in a mold, which is filled with the
material |
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| cellulose |
most commonly occurring carbohydrate; cotton, jute, flax, and hemp are
almost pure cellulose |
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| carbon-fiber-reinforced plastic (CFRP) |
carbon-fiber-reinforced plastic (CFRP)-a composite material of carbon
fibers and a polymer matrix |
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| CNC |
Computer controlled machining |
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| Computer-aided design (CAD) |
to produce a single unambiguous digital definition of geometry in such
format as to be suitable for integrated, seamless design and manufacture |
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| cross-linking |
linking together of polymer molecules (macromolecules) by primary
valences, resulting, in most cases, in a three-dimensional network;
cross-linking of certain plastics can be carried out chemically by the
addition of appropriate bridge-building monomers |
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| CRP |
carbon-reinforced plastic; see CFRP |
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| crystalline |
consisting of numerous tiny crystals that are not completely formed |
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| crystalline melting temperature |
crystalline regions of a thermoplastic melt at this temperature (Tm) |
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| Decomposition temperature |
the temperature (Td) at which a material is destroyed by chemical
decomposition |
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| delamination |
detachment of the fibers from the matrix, or a crack in the matrix
running parallel to a laminate layer |
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| elongation |
the change in the length of a body pulled in one direction by the
application of a force |
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| EPS |
expanded polystyrene (foamed polystyrene) |
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| Filament |
a continuous thread of a specified diameter, e.g. silk (natural fiber)
or rayon (synthetic fiber); the opposite of a fiber with a finite length,
such as wool or cotton |
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| flow temperature |
temperature above which a thermoplastic can be reshaped with little
force |
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| FRP |
fiber-glass-reinforced plastic is a composite material consisting of
glass fibers |
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| gel coat |
resin layer (usually colored) that protects the underlying resin/glass
fiber laminate from external influences such as impact, UV light,
chemicals, etc.; the side of the molded part that remains most visible or
external after demolding, hence the gel coat is the first layer applied to
the mold |
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| glass transition temperature |
amorphous regions of a thermoplastic soften at this temperature (Tg) |
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| granulate |
plastic starting material for primary processing; particles are
usually in the form of lentil-shaped cylinders |
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| hardener |
second chemical component required for activating the cross-linking
reaction of prepolymers, in order to manufacture thermosets or elastomers |
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| holding pressure |
conveys additional melt into the molded part as it solidifies in the
injection molding process, thus minimizing shrinkage (loss of volume) that
would otherwise occur as the injection-molded part cools; it also
compresses the internal structure of the part |
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| hydraulic |
operated by the pressure of a liquid |
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| injection molding cycle |
represents the total of the durations of all operations performed
within the injection molding machine and necessary to manufacture a part |
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| injection pressure |
pressure applied by the screw against the molding compound to push it
into the mold in the injection process |
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| isotropy |
condition in which properties are completely independent of direction
(isotropic), i.e., the same in all directions |
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| laminate |
the cured thermoset matrix or the cooled fiber-reinforced composite
(with a thermoplastic matrix) |
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| layered structure |
structure and arrangement of the individual layers (laminate) of a
fiber-reinforced composite |
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| locking force |
force required to close the mold while being filled or during the
hardening phase (in the case of thermosets) |
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| matrix material |
material that binds the fibers |
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| melt |
molten molding compound |
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| melting temperature range |
temperature range (Tf) within which a solid material changes to a
liquid state |
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| modulus of elasticity (E-modulus) |
constant ratio of stress to deformation within the elastic range of a
material, determined by tensile test, compression test, and bending test;
because of the viscoelastic characteristics of plastics, dependence on
time is an important consideration |
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| molded part |
plastics part produced by primary processing; can often be used
without subjecting it to a finishing operation |
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| molding compound |
an unformed or preformed material that can be processed by noncutting
methods of shaping (primary processing) within a certain temperature range
to form a molded material, which may be a molded part or semifinished
product |
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| monomer |
basic building block from which macromolecules are created; for
example, ethylene is the monomer of polyethylene ("monomer" is derived
from the Greek word for "single part") |
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| multifunctional |
multiple functions combined in a single component; for example, a
cable on a ceiling light may bear the weight of the lamp itself while also
conducting the electrical energy to the lamp |
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| nonwoven |
nonwoven, solid, flat sheet consisting of bundled glass filaments or
glass staple fibers (surfacing mat) |
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| orthotropy |
also known as orthogonal or rhombic anisotropy, it indicates that
properties depend on direction; the properties are symmetrical in relation
to a system of three perpendicular (orthogonal) planes |
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| PA |
polyamide (a sernicrystalline thermoplastic) |
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| PC |
polycarbonate (an amorphous thermoplastic) |
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| PE |
polyethylene (a sernicrystalline thermoplastic) |
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| PEEK |
polyether etherketone (a semicrystalline thermoplastic) |
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| PES |
polyether sulfone (an amorphous thermoplastic) |
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| plasticizers |
substances that bring about softening of plastics; in a physical
sense, plasticizing means decreasing the glass transition temperature (Tg)
of a polymeric material, generally to a point below room temperature so
that plastics that are initially hard, rigid, and brittle become soft,
flexible, and impact resistant |
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| Plasticate (plastify) |
describes the conversion of a plastic material to a thermoplastic
condition by the introduction of heat |
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| Polarity (of plastics) |
formation of electrical charge distributions within the macromolecules
produces various polarities |
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| polymers |
long molecular chains (chain molecules) formed from monomers occurring
as repetitive "building blocks" or monomer units in these chains
("polymer" is derived from the Greek word for "many parts") |
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| POM |
polyoxymethylene (a semicrystalline thermoplastic), also known as
polyacetal |
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| prepregs |
molding compounds consisting of flat or linear glass reinforcements
preimpregnated with thermosetting resin compounds; molding com pounds
prepared in this way are mostly glass fiber mats or glass filament cloths
processed to form molded parts or semi-finished products by hot-press
molding |
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| PVC |
polyvinyl chloride (an amorphous thermoplastic) |
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| quasi-isotropic |
a condition in which properties are nearly identical in all
directions; in fiber reinforced composites; this condition can be
attained by providing at least three directions with reinforcement in
similar layer thicknesses |
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| Rapid prototyping (RP) |
The production of a limited number of components originating directly
from a CAD definition in a time-compressed manner |
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| Rapid tooling (RP) |
The direct use of CAD data in the production of a mold or fixtures for
the manufacturing of a part. It also includes the production of a mold
utilizing time reducing technologies. |
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| raw material |
naturally occurring starting material used to manufacture a product,
such as petroleum, coal, ores, wood, hides, and cotton, as well as water
and air; the intermediate product (semi-finished product) is formed from
the raw material during the production process, and the finished
(manufactured) products are produced from the intermediate product |
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| recycling |
reutilization of raw or used materials; for example, plastic sprues
from injection-molded parts are recycled by processing them to form a
granulate, which is then returned to the injection molding process |
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| resin |
amorphous material with a consistency that can vary from soft to
rigid; then-nosetting resins form the basis for thermoset plastics |
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| resin injection process |
a closed mold is used to manufacture molded parts from resin, and
reinforcing materials are inserted into the molded parts |
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| RIM |
reaction injection molding, which refers to an integrated mixing and
injection process for plastics from two or more highly reactive components |
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| roving |
refers to a certain number of approximately parallel glass strands
combined to form a larger strand (or glass roving); an individual glass
strand consists of a certain number of individual glass filaments that
have been combined without twisting to form a thread of uniform size, and
these filaments are arranged in a mostly parallel relationship |
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| SLA |
Stereolithography |
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| SLS |
Selective laser sintering |
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| sandwich |
flat multilayer composite design consisting of two high-strength outer
layers and a light, thick inner layer; this design provides a high surface
moment of inertia and great stiffness |
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| sealing point |
time at which the molding compound inside the sprue channel has become
solid enough to prevent any further flow |
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| self-extinguishing |
ability of a burning plastic to extinguish itself without external
influence |
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| semifinished product |
intermediate product made of plastic (e.g., pipes and sheets), which
will be further processed (reshaped) to form a finished product |
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| shear strength (interlaminar) |
property defined as the force sufficient to cause a rupture within the
area subjected to shear divided by the area subjected to shear |
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| sonotrode |
welding tool used in ultrasonic welding to transmit vibrations to the
plastics part being welded |
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| sprue bush |
part of an injection mold that lies against the nozzle of the
injection unit and through which the molding compound flows into the mold |
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| stabilizers |
chemical additives that make a plastic more resistant to certain
influences (e.g., UV radiation, heat, oxidation, weathering) |
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| synthesis |
formation of chemical compounds from the basic elements or basic
chemicals with a simpler structure ("synthesis" is derived from the Greek
word for "put together") |
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| Thermoplastics (semicrystalline) |
thermoplastics displaying crystalline and amorphous regions; plastics
that can be melted (softened) by application of heat |
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| thermoset |
polymer in which the chain molecules are cross-linked in three
dimensions through covalent bonds |
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| ultimate elongation |
the elongation that the body exhibits before breaking at the maximum
amount of force; specified as a percentage of the starting length |
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| unidirectional |
aligned in one direction |
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| viscoelastic |
condition of a body that is both elastic (Hookean) and viscous
(Newtonian) |
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| vulcanization |
chemical cross-linking process that alters the properties of natural
rubber to make it elastic and resistant to distortion |
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