Page 249 - The Jet Engine

Manufacture

Fig. 22-12 Typical automated manufacture of compressor blades.

from the actual centre of the explosion, the metal is
torn into fragments which may themselves be melted
by the intense heat. The dielectric medium, usually
paraffin oil. pumped into the gap between the tool
electrode and the workpiece, has the tendency to
quench the explosion and to sweep away metallic
vapour and molten particles.
41. The amount of work that can be effected in the
system is a function of the energy of the individual
sparks and the frequency at which they occur.

42. The shape of the tool electrode is a mirror image
of the passage to be machined in the workpiece and,
to maintain a constant work gap, the electrode is fed Fig. 22-13 Electro-discharge machining
into the workpiece as erosion is effected. circuit.

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