January 2011 Tube Products International
49
for tube making
AK Steel has reached a new milestone,
marking 100 years of innovation at its
research facility in Middletown, Ohio.
The company’s predecessor, Armco,
announced the creation of a research
department on 22 September 1910. Since
that time, AK Steel has been an industry
leader in new product development,
customer technical services and
steelmaking process improvements.
“AK Steel has a proud heritage of
research and innovation,” said James
L Wainscott, chairman, president and
CEO of AK Steel. “Throughout historic
PolyMedex Discovery Group has
announced the availability of custom
multi-layer tubing composed of
thermoset polyimide and thermoplastic
elastomer (TPE) laminate. Through a
manufacturing process developed
by PolyMedex, the high strength and
tight tolerances of thermoset polyimide
are combined with the wide variety
of material options and configurations
available in thermoplastic elastomers.
Polyimide and TPE composite multi-
layer tubing is suitable for demanding
medical device applications that require
a combination of high performance and
manufacturability.
The primary value of the polyimide and
TPE multi-layer tubing is the ability
to utilise the benefits of thermoset
polyimide, while mitigating its limitations.
Thermoset polyimide has a minimum
tensile strength of 20,000 psi (138
MPa) which is 30% greater than high
performance thermoplastics such as
polyetheretherketone (PEEK). Due to
its hard and glossy surface, polyimide
is suitable for device working channels,
improving passability of metallic devices
such as implants. Polyimide is also
resistant to the harshest chemicals and
features a dielectric strength of 10,200
volts.
Thermoset polyimide tubing can be
produced with ID tolerances in the range
of ±0.0002" to ±0.0005" (0.0051 to
AK Steel marks 100 years of
research and innovation
Multi-layer polyimide and TPE tubing
eras of technological, regulatory and
industrial changes in American history,
AK Steel has held, and continues to
hold, a leading position in the area of
steelmaking research.”
Among the products and processes
developed by AK Steel throughout its
history, the company pioneered the
world’s first continuous hot rolling
sheet mill in the 1920s. Its research
also led to the development of various
types of electrical steels used in
power transmission and distribution
equipment. The company also helped
0.013mm) depending on diameter. This
makes the material suitable for small
diameter vascular device assemblies
where high strength and tolerance
stackup are a critical concern.
The greatest limitation of thermoset
polyimide tubing is that it is available only
in a round single lumen configuration
and is difficult to bond, colour or thermal
form. In contrast, TPEs can be extruded
in virtually unlimited configurations,
including profiles and multilumen. A wide
variety of durometers and stiffnesses
allow TPE polymers to solve a broad
range of medical device challenges.
TPE tubing can also be thermally formed
after extrusion to create critical catheter
components such as traumatic tips and
flares for connector fittings.
By integrating the two resins, the
PolyMedex composite multi-layer tubing
features the best benefits of thermoset
polyimide and TPE tubing.
PolyMedex Discovery Group serves
medical device manufacturers with
comprehensive development and
manufacturing services for intravascular,
minimally invasive, and implantable
applications.
Its capabilities include polymer distribu-
tion, custom compounds, bioresorbable
and drug delivery formulations,
thermoplastic and thermoset tubing, and
custom components.
PolyMedex Discovery Group
– USA
revolutionise the automotive exhaust
market in the 1990s with the introduction
of specific types of aluminised stainless
steels. Today, in addition to several
other research projects, AK Steel
is developing products that help its
automotive customers design lighter,
more fuel-efficient vehicles.
AK Steel produces flat-rolled carbon,
stainless and electrical steels, primarily
for automotive, appliance, construction
and electrical power generation and
distribution markets. AK Tube LLC, a
wholly owned subsidiary of AK Steel,
produces carbon and stainless electric
resistance welded (ERW) tubular steel
products.
AK Steel
– USA
Multi-layer composite tubing
