Project ForgeManufacturing Engineering
Machining Processes
GATE 2018
Medium
An electrochemical machining (ECM) operation is to cut a through hole into a 12 mm thick aluminum plate. The hole has a rectangular cross-section, 10 mm × 30 mm. The operation will be accomplished in 2 minutes, with efficiency of 90%. Assuming specific removal rate for aluminum as 3.44×10⁻² mm³/(A·s), the current (in A) required is __________ (correct to two decimal places).
969 A(± 0.2 accepted)
Explanation
Volume to remove = 12×10×30 = 3600 mm³, in time 120 s: required MRR = 3600/120 = 30 mm³/s. With efficiency η=0.9: 30 = η×(specific removal rate)×I = 0.9×0.0344×I → I = 30/(0.9×0.0344) ≈ 969.0 A.
Source: GATE ME 2018 Session 1 (Set 1) (2018)
This question is part of a 15-day revision cycle — sign in and Project Forge will bring it back the day before you'd forget it.