New Technology Cuts Fine Detail In Titanium And Tungsten
Carbide
The use of electrochemical machining (ECM) in the aerospace
industry is well known for applications such as blades and blisks,
but it requires considerable skill and experience to produce a
viable electrode. The ECM 500, developed by Electrosion, based in
Barnsley, UK has resolved this problem and enables the technology
to be easily applied to a much wider range of applications, thanks
to its revolutionary Impulse technology.
ECM uses electrolytic principles to erode the workpiece,
dissolving the waste material in the sodium nitrite electrolyte.
The advantages are speed, accuracy, surface finish, zero electrode
wear and the ability to cut any metal irrespective of its
hardness.
The main disadvantage, up until now, has been the wide gap
required between the electrode and the job to achieve sufficient
electrolyte flushing. This has made it difficult or impossible to
machine fine detail and has made electrode design complex, as its
shape can be significantly different from that of the finished
part.
The new Impulse technology on the ECM 500 overcomes this
limitation by oscillating the electrode and pulsing the current
simultaneously. The result is that electrode gaps down to 10
microns can be used and, because the shape of the electrode is now
identical to the finished part, it makes it easy to produce
intricate shapes.
Steve Duffield, Managing Director of Electrosion said, " The ECM
500 can achieve material removal rates of 1000 mm3/min and
routinely produce surface finishes of 0.1 Ra and, with care, 0.03
Ra."
Compared with EDM, ECM is 100 times faster. Furthermore, a
feature of ECM is zero electrode wear, which means that the ECM 500
only requires one electrode to cut multiple parts or cavities,
saving the cost and time involved in producing the roughing and
finishing electrodes required for EDM.
The ECM 500 can erode the hardest and most difficult to machine
materials, including tungsten carbide and titanium, at low
temperature, without any load on the part. For aerospace designers
and manufacturers there are considerable benefits, as the process
does not introduce any stress into the part, and difficult to reach
features, which can only be reached with a very long tool, can be
accurately and repeatedly machined without electrode wear or
deflection.
The new capabilities for eroding fine detail will allow
engineers to economically apply the advantages of ECM to a much
wider range of parts, enabling designs to be optimised using harder
materials where appropriate, without having to consider the
limitations of manufacturing methods.
Fuzzy logic principles in the control system on the ECM 500 have
made the machine easy to operate and suitable for a production
environment. Technology in the control adjusts the settings to suit
each material and job, eliminating the need for highly skilled
workers.
Duffield added, "With the ECM 500 we have simplified the process
and overcome the associated limitations, making it a method of
manufacture that can be used for many different applications. It is
particularly beneficial for fragile parts made from exotic
materials, which are difficult to machine in any other way.
"Now that we can produce intricate shapes, ECM can become a
mainstream production method and aerospace designers and
manufacturers will have much more freedom to make complex parts
which would have previously been very costly or impossible to
produce."
Electrosion is an ECM manufacturing company based in the north
of England. It specializes in producing ECM machines for
manufacturers across the world. Its range of machinery stretches
from deburring machines, to large titanium machining production
systems valued in excess of $1.5m. Electrosion constantly invests
in R & D, and is a double SMART award winner for innovations in
ECM.