Injection Or Fill Time
Time required to fill the cavity or mold.
Injection Compression Molding
A method of molding where the
plastic is injected into a partially open cavity with
injection pressure typically 50-75% lower than standard
injection molding depending on wall thickness and mold open
distance. The 2nd stage clamp action closes the telescoping
core and subsequently compresses and distributes the melt into
the far extremities of the cavity, including ribs and bosses.
The method of forming objects from granular
or powdered plastics, most often of the thermoplastic type, in
which the materials is fed from a hopper to a heated chamber
in which it is softened, after which a ram or screw forces the
material into a mold. Pressure is maintained until the mass
has hardened sufficiently for removal from the mold.
The applied hydraulic pressure used to push
the resin into the mold cavity.
The elapsed time required to fill the mold
A removable part of the mold imparting increased
resistance to wear or heat transferability to that area of the
An article of metal or other material which is
incorporated into a plastic molded part either by pressing the
insert into the finished molded part or by placing the insert
in the cavity so that it becomes an integral part of the
Insert Pull-Out Strength
Force required to pull an insert
straight out of a material at least 0.020" thick. Insert
performance criterion maintained for the most part in molded
A pin that
ejects a molded article from the mold. Land Area The area of
surfaces of a mold which contact each other when the mold is
Land (Gate Area)
Gate dimension parallel to the direction of
L/D Ratio Extrusion
Barrel length divided by the diameter of
Any of a number of
processes, such as drilling, turning, sanding, etc., which may
be performed on a piece of plastic.
The resistance of glossy plastic surfaces to
A masterbatch is
a concentrate of colorants or additives properly dispersed
into a carrier polymer, which is then blended into the natural
polymer to be coloured or modified.
of the information on each material acceptably tested for use
in MOLDFLOW analyses.
The molten material
which will fill the mold cavity to form the part.
Also referred to as a plunger. A large
capacity holding area for molten resin. The area of a
structural foam molding machine that determines the shot size.
The amount of a thermoplastic resin, measured in
grams, which can be forced through a specified orifice within
ten minutes when subjected to a specified force. (ASTM D-1238)
The strength of the plastic while in the molten
state. This is a pertinent factor in extrusion, blow molding
and drawing of molten resin from a die.
The melt temperature or Tm is the
temperature, measured under specified conditions, at which crystallinity disappears in a semi-crystalline polymer.
Semi-crystalline materials have a clearly defined melt
temperature. Amorphous materials soften over a wide
temperature range above their glass transition temperature.
They do not have a specific Tm, but a melting range. Melt
temperature should be measured from a purge shot having the
same residence time as in the production process.
Phenomena accompanying the softening of a
material under the influence of heat: can be shrinking,
dripping and burning of molten material. Melt drip: falling
droplets of molten material, either burning or not.
molding, a lubricant used to coat the surface of the mold to
enhance ejection of the molded article or prevent it from
sticking to the tool. Many resins are available with an
internal mold release.
The difference in dimensions between the mold
and the molded part.
The temperature at which the mold is
maintained. Often the most important benefit of raising mold
temperature is that it allows a slower injection rate without
the plastic getting too cold.
The purpose of mold venting is to exhaust air
from mold cavities to enable the inflation of the part.
Drilled holes, vent bushings and continuous venting along mold
seams are typical methods. If venting is needed on appearance
surfaces, the vents are sometimes textured to match the part
The temperature of the mold and melt and
the time required to fill the mold.
The period of time occupied by the complete
sequence of operations on a molding press requisite for the
production of one set of molded articles.
The pressure applied to the ram of an
injection machine or press to force the softened plastic
completely to fill the mold cavities.
The variability of the pressure to fill
the cavity and temperature of the melt at the part as
influenced by changes in injection time and barrel melt
A monomer is the
molecular unit from which polymers are prepared. A polymer is
a molecular chain formed by combining many smaller molecules.
Polymers are the product of a reaction called polymerization,
the process of connecting many (poly) single units (mers or
mono-mers) to form long chain molecules of higher molecular
weight. Polymerization reactions may be controlled to produce
molecules of a specific length or molecular weight. All
plastic resins or materials are polymeric in nature.
Multiple Cavity Flow
Produces more that one identical part with each cycle.
Hollow metal hose screwed into the extrusion end of
the heating cylinder of an injection machine designed to form
a seal under pressure between the cylinder and the mold