A Hybrid Machining Process Combining Micro-EDM and Laser Beam Machining of Nickel–Titanium-Based Shape Memory Alloy

TLDR

Micro‑EDM is slow yet yields good surface quality, whereas laser machining is fast but produces poorer surfaces. The study proposes a hybrid laser‑EDM process to drill microholes in Ni–Ti shape memory alloy, aiming to combine the speed of laser with the surface quality of EDM. The hybrid process drills pilot holes with a laser and then rim‑drills them with micro‑EDM, with parameter studies conducted to identify optimal EDM conditions. The hybrid method cut machining time by 50–65 % while maintaining microhole quality relative to conventional micro‑EDM.

Abstract

Micro-electrical discharge machining (EDM) is a slow process as compared to laser machining, on the contrary laser machining lacks good surface quality. To overcome the drawbacks of both these processes, this paper suggests a hybrid machining process which combines laser and micro-EDM processes for drilling microholes in advanced engineering materials such as Nickel–Titanium (Ni–Ti)-based shape memory alloy. To achieve the objective of the suggested hybrid process, pilot holes are drilled with laser machine and rimmed out by micro-EDM drilling. The suggested process requires investigation of various combinations of micro-EDM drilling process conditions to obtain optimum machining parameters for the hybrid process. It has been found that the proposed hybrid machining process resulted in 50–65% reduction in machining time without affecting the quality of microholes as compared to the standard micro-EDM process.