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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