24
Remanufacturing and Advanced Machining
physical and chemical interactions, and removal of infinitely thin layers of a material. The resulting models can describe efficiency and wear processes in order to
improve the process, to stabilize working conditions and prolong the working time
of diamond wheels, to normalize criteria of technical diagnostics and failure prediction, with a further adaptation of automated machining to the cyber-physical systems
(CPS) or smart factory concepts.
Some theoretical and experimental results demonstrate that in certain conditions, a stable high material removal rate (MRR) is achievable, namely between 800
and 1,000 mm 3 /min for tungsten-based cermets, and 600–800 mm 3 /min for other
cemented carbides. It is 4–5 times better than MRR for conventional grinding with
metal-bonded wheels, and 2–2.5 times better than the electrical discharge grinding (EDG) process (Uzunyan, 2003). Similar improvement is demonstrated in other
studies, where conventional electrical discharge machining (EDM) is compared to
EDG with a rotating graphite wheel and then to EDDG with a copper bonded diamond wheel (Govindan and Praveen, 2014). In the case of machining of Al–SiC
composite and titanium alloy, the MRR obtained by the EDDG process is about five
times greater than for the EDM and about two times more than for the EDG process.
The improvement is reached at low costs, high surface quality, and a high wear resistance of the diamond wheels. According to Uzunyan (2003), the cost of the EDDG
process and the relative wear of diamond wheels can be reduced by between 25%
and 50% compared to the conventional diamond grinding.
1.5 ELECTRICAL DISCHARGE MACHINING METHODS
As it was mentioned above, a method that utilizes electrical discharge in the form of
arcs or sparks is a distinct machining process (EDM) with numerous modifications.
Distinguishing between arcs and sparks is of no importance for electrical discharge
machining (Schumacher et al., 2013). During the process, small amounts of electrical conductive materials are removed according to the thermal energy (melting
FIGURE 1.5 Schematic of the electrical discharge grinding process: 1 – Metallic bond of
the grinding wheel, 2 – Diamond grit, 3 – Ground part, 4 – Electrical discharge, 5 – Chip.
Remanufacturing and Advanced Machining
physical and chemical interactions, and removal of infinitely thin layers of a material. The resulting models can describe efficiency and wear processes in order to
improve the process, to stabilize working conditions and prolong the working time
of diamond wheels, to normalize criteria of technical diagnostics and failure prediction, with a further adaptation of automated machining to the cyber-physical systems
(CPS) or smart factory concepts.
Some theoretical and experimental results demonstrate that in certain conditions, a stable high material removal rate (MRR) is achievable, namely between 800
and 1,000 mm 3 /min for tungsten-based cermets, and 600–800 mm 3 /min for other
cemented carbides. It is 4–5 times better than MRR for conventional grinding with
metal-bonded wheels, and 2–2.5 times better than the electrical discharge grinding (EDG) process (Uzunyan, 2003). Similar improvement is demonstrated in other
studies, where conventional electrical discharge machining (EDM) is compared to
EDG with a rotating graphite wheel and then to EDDG with a copper bonded diamond wheel (Govindan and Praveen, 2014). In the case of machining of Al–SiC
composite and titanium alloy, the MRR obtained by the EDDG process is about five
times greater than for the EDM and about two times more than for the EDG process.
The improvement is reached at low costs, high surface quality, and a high wear resistance of the diamond wheels. According to Uzunyan (2003), the cost of the EDDG
process and the relative wear of diamond wheels can be reduced by between 25%
and 50% compared to the conventional diamond grinding.
1.5 ELECTRICAL DISCHARGE MACHINING METHODS
As it was mentioned above, a method that utilizes electrical discharge in the form of
arcs or sparks is a distinct machining process (EDM) with numerous modifications.
Distinguishing between arcs and sparks is of no importance for electrical discharge
machining (Schumacher et al., 2013). During the process, small amounts of electrical conductive materials are removed according to the thermal energy (melting
FIGURE 1.5 Schematic of the electrical discharge grinding process: 1 – Metallic bond of
the grinding wheel, 2 – Diamond grit, 3 – Ground part, 4 – Electrical discharge, 5 – Chip.