Extruding Machines for Plastics, Single Screw [Telford Smith]
Telford Smith Extruders for your process with throughputs up to
Whether you are producing pipe, profile, film, wire and cable, sheet, fibre or
compounding, there is a Telford Smith Extruder, and a team of experts to supply
you the equipment, so you can produce quality product at the rate you need to
remain competitive. Each process is unique and the significant common
denominator is the Telford Smith Extruder.
Telford Smith's fabricated Extruder base provides substantial rigidity that
accurately maintains the axial alignment of the screw to the gearbox. An
adjustable barrel support provides precise alignment and compensates for barrel
expansion and contraction while in operation.
Where do you want your Extruder? Will you need to move it? From mono to
co-extrusion we customise every base to your requirements from an infinite
selection of centre line heights with manual or mechanical height adjustment
available. You also choose whether you want the Extruder stationary with
levelling screws and bolt down holes incorporated or mobile with castors or vee
wheels. We engineer to suit your specific requirements and factory layout.
The heart and soul of the machine determining its plasticising capabilities.
Telford Smith depends upon the superior design and manufacture of the screws we
make as that of our Extruders. We have over 70 years experience in manufacturing
and repairing screws from the entire spectrum of plastics processing equipment.
We have established our name, which is synonymous with quality, as well as an
invaluable database of reference material. Telford Smith provides conventional
screw design tailored to your output and quality requirements, covering the full
range of thermoplastics from Vinyls to Elastomers.
However, today's standards for Extruder output and extrudate quality are so
advanced that no longer can one screw design be optimum for all materials and
extrusion products. Each screw must be tailor made to suit the application for
which it will be used. We continuously liaise with resin suppliers and screw
design modellers to keep us at the forefront of screw technology … far and ahead
of our competition.
Telford Smith provides the best screw for your product individually designed to
obtain the proper balance between high output and quality homogeneous melts. The
best screw may even be one of the Telford Smith's designed special application
screws such as maddock mixing screws, 2-stage screws for vented barrels or even
our barrier screws.
Telford Smith are consistently on the leading edge with High Performance Plastic
Extrusion Screw Designs to maximize machine efficiency and product quality.
Barrel Heating and Cooling
Telford Smith Extruders are equipped with finned, ceramic band heating elements
that maintain intimate contact with the barrel at all temperatures. This ensures
that a uniform temperature profile is maintained, which prevents thermal
distortion of the barrel. Each element is air-cooled individually by ducted
blower fans giving rapid airflow and good heat dissipation ensuring precise
temperature control. Copper-finned elements increase the area for heat removal,
and therefore are extremely responsive. The more traditional cast aluminium type
heater elements are still used when water-cooling is better suited to your
process or production needs.
Compatibility between the screw and barrel is crucial to wear resistance,
product quality and machine output. XALOY bimetallic barrels provide a choice of
alloys to suit your specific needs for resistance to abrasive and corrosive
wear. Telford Smith Engineering is the Australasian Agent for XALOY USA, the
industry benchmark. World-class quality from ISO 9001 registered facilities,
improved structural backing steels and manufacturing techniques set XALOY
barrels apart in consistency and reliability. We offer the full product range of
XALOY barrels, which include these recognised types:
X-102 sets industry standard for general-purpose bimetallic barrels. Since its
introduction in 1991, X-102 provides greater resistance to corrosion and
abrasive wear when compared to generic substitutes from other suppliers X-102 is
a chromium-modified boron-iron alloy.
X-800 gives exceptional wear resistance. For both abrasive wear and corrosion
resistance X-800 leads the industry. X-800 is a composite of particles of
tungsten carbide, one of the hardest materials known, uniformly dispersed in a
matrix of corrosion-resistant nickel alloy. Micro hardness testing is used to
test the wear resistance of X-800 because it is a composite. Conventional
Rockwell testing, involving a ball indentation device, only measures the
hardness of the matrix alloy. Micro hardness testing homes in on the tungsten
carbide particles that provide X-800's exceptional resistance to abrasive wear
with readings of 1200 Knoop.
X-309 gives superior corrosion resistance. For the most severe corrosion
environments X-309's nickel-boron-chrome alloy, which has less than 1% iron is
the best choice. This eliminates melt contamination caused by iron-based alloys.
Alternatively Telford Smith manufactures nitrided barrels, typically used on
mild abrasive applications, and fully hardened and nitrided barrels,
predominantly used for glass filled moulding applications.
Optional vent stacks on Telford Smith Extruders provide removal of volatiles
through a vent opening in the barrel. Vacuum venting systems are available as an
This component consists of a single clamping bolt and Vee-clamp allowing quick
screen changes. This proven design ensures safe clamping of the head to the
barrel with a uniformly positive seal against high-pressure extrudate leakage.
An over pressure rupture plug is fitted to the barrel as a safety precaution
against excessive barrel pressure build-up. An optional 3-piece clamp provides
support to heavy dies or adaptors as they are moved into position for clamping
or out of position to allow screen pack change. The barrel termination can also
be threaded for screen changer connection or simply flanged with tapped holes.
This essential component is designed for the free flow of pellets, beads or
powder into the screw flights. We offer two types of feed designs; integral with
the barrel or independently mounted. Both are available with smooth bore
(conventional) or grooved feed (high pressure) liners depending on application.
The feed throat opening is machined directly into the Barrel with a
water-cooling jacket fitted to prevent bridging. The independent feed design on
larger Extruders is fabricated in cast steel with an integral water-cooling
jacket. A separate replaceable liner is press fitted into the bore that can be
replaced with minimal expense and downtime.
Telford Smith feed hoppers are constructed using powder-coated steel with sight
glasses, dump chute and cut off slide standard with various sizes to suit the
Extruder and application.
Gearbox and Thrust Assembly
This highly critical component is designed, built and tested for durability and
reliability throughout a long service life. The precision-machined system
reduces motor RPM to a suitable screw speed, provides a drive for the screw that
is concentric to the barrel bore length and absorbs the heavy thrust developed
by the polymer melt pressure.
Heavy-duty, double reduction helical gears are used, manufactured from 18 Ni CR
Mo 5 casehardened steel. The low speed gear shaft receives the screw-shank that
is driven by a single key way. The spherical roller-type main thrust bearing is
mounted against a large flange for maximum load capacity.
For gearboxes with a lower thermal dissipation than the applied mechanical
power, an internal water-cooled coil is provided and a simple connection to a
water supply is required.
Main Drive Motor
DC motors with tacho generator feedback are standard and most popular on Telford
Smith Extruders. AC motors (open loop) are also available as well as AC motors
with an encoder fitted (closed loop) which provide unmatched speed holding
capabilities. The motor can be mounted on either side of the Extruder or tucked
under to suit the gear case, providing flexibility for your operation. Belt
drive transmission is always used on smaller machines however when the drive
power exceeds 340kW, direct drive is standard.
You cannot produce a precision product without precise temperature control.
Product variation results in wasted material and production. All electrical
systems are designed by Telford Smith Engineers who specify only the highest
quality components meeting rigid specifications. The easy to read operator
interface displays controls and instrumentation for all zones, temperatures,
alarms and deviations. Your choice of mounting the pre-wired cabinet on the
machine base or a freestanding cabinet wired to an on-site junction box. The
junction box is fitted by Telford Smith and is pre-wired to the Extruder.
With the emphasis on health and safety all our Extruders are fully guarded for
operator protection from heat, electrical and mechanical equipment. Appropriate
warning labels are displayed where necessary.