Factors influencing the method to adopt included quality,
hole shape, cost, ease of upgrading existing machinery and
level of complexity. The goal was to have a solution that
was relatively cheap, that would be stable in a production
environment and relatively easy to implement and integrate
in existing systems.
Feeding the electrode at the desired angle for the hole taper
and rotating at the same time was seen as the solution
that could guarantee consistent hole shape and quality. The
principle was relatively simple to realise, the cost implication
was minimal compared to the other solutions, and it
could easily be adapted to fit existing equipment. The concept
also had possible advantages for drilling straight holes