Question

An electrochemical machining (ECM) is to be used to cut a through hole into a 12 mm thick aluminium plate. The hole has a rectangular cross-section, 10 mm × 30 mm. The ECM operation will be accomplished in 2 minutes, with efficiency of 90%. Assuming specific removal rate for aluminium as $3.44\times {10}^{-2}m{m}^3/\left(As\right)$, the current (in A) required is (correct to two decimal places.)

Answer 1

Volume of metal to be removed
$=(10\times 30)\times 12m{m}^3=3600m{m}^3$
Ideal energy required

$=\frac{3600m{m}^3}{3.44\times {{10}^{-2}}_{\left(As\right)}^{{}^{m{m}^3}}}$

$=104651.163As$
Actual energy required

$=\frac{104651.163}{0.9}As$

$=116279.07As$
Time is 2 min = 120 s

$\therefore Current=\frac{116279.07}{120}A=968.992A$