High-throughput Dry and Minimum Quantity Lubrication Drilling of Compacted Graphite Iron

This research investigates the high-throughput drilling of the compacted graphite iron (CGI), a high strength, lightweight material for automotive powertrain applications, at 26.5 mm/s feed rate using 4 mm diameter coated carbide drill. The CGI drilling experiments show that maximum 1740, 3150 and 2948 holes were drilled in two repeated tests under the dry, dry with through-the-drill compressed air, and minimum quantity lubrication (MQL) conditions. The Joule-Thomson cooling effect due to expansion of high pressure air from holes at the drill tip and mechanical effect of chip formation and evacuation are studied. Results demonstrate that high-throughput sustainable dry drilling of CGI is technically feasible.