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About Extruded Plastics
Extruded plastic is plastic that has gone through an
extrusion process. In this continuous process, thermoplastic resins or
plastic polymers are melted, heated and pumped. Molten plastic material
is pulled through a calibration system, which includes a die. The die
shapes the plastic into the desired shape, or profile. Single- or twin-screw
plastic extruders use one or more internal screws in a barrel to melt,
mix and push the melted plastic material through the die. This plastic
extrusion process shears material between the root of the screw and the
wall of the barrel that surrounds it, creating frictional energy that
heats and melts the substance as it moves down the barrel. The barrel
is also heated electrically to provide the necessary heat to melt the
plastic material. A high intensity mixer is another type of plastic extruder.
In sheet plastic extrusions, plastic powder or pellets are cut into sheets
or rolls. The plastic sheets are then thermoformed, a plastics extrusions
process in which they are re-softened in ovens and then brought into
contact with a mold surface by either air pressure or vacuum. The mold
determines the inside or outside shape of the part, as it comes into
contact with only one side of the softened plastic. The sheet extrusion
process can form extremely large sheets, up to and exceeding 2” thick
and as wide as 30 ft, which allows the production of very large parts
on an economical basis. Two or more plastic extruders can be used to
co-extrude sheet products to produce multi-layer structures with distinct
layers of plastic polymers. This plastic extrusion process adds functionality
and improves the cost performance ratio of the end extruded plastic products.
Extrusion blow molding is used to produce plastic bottles, such as milk
jugs and shampoo and bleach bottles. This plastic extrusion process utilizes
a die similar to that used for making plastic pipes. Plastic pellets
are fed into a blow molder, which is the hopper of the machine. A screw,
located inside a heated barrel, pushes forward the softened plastic,
which is then forced through a circular die, forming a plastic tube called
a parison. Inside a hollow mold, the parison is clamped and inflated
from within by pressurized air. The plastic bottle is then ejected and
sent on to trimming, printing and filling stations.
Many different types of plastics can used in plastic extrusions, and
each has its own advantages. High impact styrene (HIS) has a uniform
matte finish after extrusion, is a cost effective material, can be easily
colored and has good impact resistance. HIS plastic extrusions are suitable
for indoor applications and may have a UV inhibitor added. Rigid vinyl
(R/PVC) is moderately priced, tough and versatile, provides good clarity
and is available in clear to opaque colors with a moderately lustrous
finish. R/PVC plastic extrusions are used for outdoor and indoor applications.
Butyrate (CAB) plastic extrusions provide very good quality of clarity,
have good flexural strength and a high gloss finish and are typically
used for their clear forms. ABS plastic extrusions are tougher, shinier
and higher priced than HIS, though worth the cost, if the properties
are necessary. Polyethylene (PE) plastic extrusions are an economically
priced and of flexible material that can be coiled or spooled in its
extruded form and can be cut in the field. When more rigidity is required
for PE, high density formulations are available. Other materials used
in plastic extrusions include flexible vinyl (F/PVC), acrylic (also called
Plexiglass), SAN, polypropylene (PP) and K-Resin. Suppliers of plastic
extrusions may have a number of materials in stock: ABS, acrylic, butyrate,
fiberglass, nylon, polyamide, polycarbonate, polyethylene, polyethylene
terepthalate glycol, polypropylene, polystyrene, PTFE, polyurethane,
urethane and PVC.
Custom plastic extrusions are available in many shapes, including thin
film plastic extrusions, plastic sheets, plastic rods, wire plastic extrusions
and any other custom plastic extrusions to be configured. Methods utilized
to create custom plastic extrusions include hot plastic extrusion, cold
plastic extrusion, co-extrusion, dual plastic extrusion, multi-durometer
plastic extrusion, hydrostatic plastic extrusion, impact plastic extrusion,
pultrusions, reverse plastic extrusion, backwards plastic extrusion and
wire drawing plastic extrusion. Hot-working plastic extrusion processes
use the good deformability of heated metallic or thermoplastic materials
for shaping them.
Featured
Articles
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http://www.inplexllc.com/material.htm
Types of Extruded Plastic
- is material that is a combination
of one or more polymers combined in the extrusion process.
- are made by pouring liquid plastic into dies.
- are strips of plastic that are shaped for
a specific purpose and cut to length.
- is produced in a continuous process resulting
in a stable net structure in which the hole size is held constant,
unlike a woven or knitted product. Extruded plastic netting is
typically utilized in vertical applications such as walls for pens,
separation
in water, filtration, predator control or barriers.
- are shapes that are formed through the
extrusion process.
- are plastic powder or pellets that have been
formed into sheet products with a range of thickness from less
than 0.010 in. (film) up to and exceeding 2.0 inches, with widths
as great
as 30 ft. This sheet can be further processed into parts via
thermoforming.
- is any tube product that has been made through the
extrusion process out of thermoplastic or other rigid, semi-rigid
or flexible materials.
- are used to make sheets, tubes, rods, and other molded plastic materials.
- are cylinder-shaped components made of plastic materials.
- are extruded products that are made of polyvinyl
chloride (PVC), including pipes, siding and floor coverings
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