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aerospace industry l engineering
Tools ISCAR
AEROSPACE IN FOCUS
The aerospace industry is not only one of the largest consumers of cutting tools but also
one of the most important driving factors for cutting tool development. The aerospace
industry features continuous efforts aimed at improving aircraft component manufacturing efficiency, increasing flight safety, and reducing potential environmental damage.
To achieve these goals, the aerospace industry must constantly improve the design of aircraft engines and airframe structural elements, to increase the protection
of the aircraft from the damaging action
of such dangerous factors as lightening
and icing. This in turn has resulted in a series of industry demands, including the
introduction of engineering materials that
require new production technologies, developing appropriate machinery and cutting tools. The aircraft manufacturer has to
deal with complex parts, which are produced from various materials with the use of
different machining strategies. This is why
the aerospace industry is considered as a
powerful and leading force for progress in
cutting tool development.
Many materials used for manufacturing
aircraft components have poor machinability. Titanium with its impressive
strength-to-weight ratio, high temperature
superalloys (HTSA) that do not lose their
strength under high thermal load, and
composites are difficult-to-cut materials.
In order to increase output rate and improve productivity, aerospace component
manufacturers must use machine tools capable of implementing advanced machining operations. In such conditions, the
role of cutting tools is significantly increased; however cutting tools can represent
the weakest link in the whole manufacturing system due to their low durability as a
system element , which can decrease productivity. Customers from the aerospace
sector expect higher levels of performance and reliability from cutting tools and tool manufacturers have been both challenged and inspired, in terms of developing
and integrating sometimes unconventional solutions into their products, to meet
these expectations.
Basic materials
d
Most cutting tools continue to be manufactured from cemented carbide. Over recent years, ISCAR has introduced several
carbide grades designed specifically for aerospace materials, including IC 5820. The
grade combines the advantages of a new
submicron substrate, a progressive hard
special 2020
T+T Technika a trh
CVD coating, and a post-coating treatment
to substantially increase impact strength
and heat resistance. The inserts from this
grade are intended mostly for milling titanium. Pinpointed wet cooling and especially
high-pressure coolant (HPC) significantly
improve grade performance.
Ceramics, another tool material, possess
considerably higher hot hardness and chemical inertness than cemented carbides.
This means that ceramics ensure much greater cutting speeds and eliminate diffusion
wear. One of the last ISCAR's developments, a family of solid ceramic endmills, is
intended for machining HTSA. These endmills are made from SiAlON - a type of silicon-nitride-based ceramic comprising silicon (Si), aluminum (Al), oxygen (O) and
nitrogen (N). When compared with solid
carbide tools, the endmills enable an increase in cutting speed of up to 50 times,
which can drastically save machining hours.
For turning applications, the company expanded its line of indexable SiAlON inserts
for machining HTSA materials. The new
products (Fig. 1) have already proved their effectiveness in turning aero engine
parts from super alloys such as Waspaloy
and different Inconel and Rene grades. In
contrast to other silicon nitride ceramics,
SiAlON possesses higher oxidation resistance but less toughness. Therefore, a key
of a SiAlON insert reliability is additional
edge preparation. ISCAR's new "TE" edge
geometry has been developed to increase
tool life in heavy load conditions during
rough operations and interrupted cuts.
Advanced geometry
d
Improving a cutting geometry is an important direction in the development of cutting
tools. Cutting geometry is a subject of theoretical and experimental researches, and
advances in science and technology have
fig. 1