Page 29 - Glass Machinery Plants & Accessories no. 6-2019

This method of processing is
a b realised through the application
of electric discharge impulses in
a regime of subexcitation. The
tool-electrode is made of graph-
ite and connected to the genera-
tor discharge circuit of current
impulse as cathode.

MATERIALS AND METHODS
Fig. 2. General view Due to the fact that the OF EXPERIMENTAL
of the transverse plates Chisinau Glass Factory faces a INVESTIGATIONS
of glass moulding forms: number of problems concerning The diagram of the technolog-
a) unprocessed; b) processed the durability of parts that are ical process of graphite deposit
through electric discharges components of glass moulding simultaneously accompanied by
in impulse
forms, namely the appearance of hardening the active surface of
such defects as zones of tearing the transverse plate by applying
worse and repairs are needed the material out of the transverse electric discharges in impulse is
to lead the machines or parts plate body (because of the adher- presented in Fig.1.
back to normal functioning for a ence of the moulded material on The interstice between the
determined period of time. the transverse plate surface fol- tool-electrode and the processed
The parts and machine aggre- lowed by the mechanical action part was invariable throughout
gates wear out during the working of the tool-machine), deforma- the processing (S = 1mm). The
process, which leads to changes tion of the transverse plate peak tool-electrode may be removed
in geometrical dimensions, form, (due to the sliding of the glass as required in the directions pre-
weight, and properties of super- mass on it, also shown through sented in the diagram. Anode
ficial layers; sometimes this can the appearance of scratches and 3 presents the part (the trans-
also lead to the appearance of cracks); marks of surface burns verse plate Fig. 2a) that was
cracks, bends, torsions, distor- (because of insufficient cooling fixed and centred with a rotating
tions and breaking. and the process of heat accumu- peak under the influence of the
Thus for normal functioning, lation in the body of the trans- tool-machine device. When, due
the parts must have functioning verse plate). The above consid- to the high power impulse gen-
security which means the abil- erably influences the decrease erated by the supplying source
ity of a part or product to work of durability of parts making up inducing unit, the electric circuit
according to its destination, with glass moulding forms, particu- between the piece-electrode and
a minimum of costs, and with- larly of transverse plates func- the tool-electrode, the interstice
in the given period and condi- tioning under the most difficult is perforated, accompanied by
tions of exploitation. Functioning conditions. the formation of the conductivity
under difficult conditions of We therefore aimed at increas-
exploitation the machines and ing the durability of cast iron
parts possess functioning secu- transverse plates by forming Fig. 3. The sketch of the
rity closely related to crack uni- graphite pellicles on their active transverse plate and the
formity and the modification of surface, accompanied by hard- points in which the measuring
structure and physico-chemical ening of the metal substratum. started beginning with zero
properties of materials, especially
on the superficial surface layer.
Graphite deposit and super-
ficial layer hardening, with the
help of electric discharges in
impulse, are based on the electric
erosion effect and polar transfer
of the tool-electrode material on
the surface of the electrode –
a part subject to the action of
thermal and electric fields in the
interstice.

glass machinery plants & accessories 6/2019 27