Experimental study on fabricating ball micro end mill with spiral blades by low speed wire electrical discharge machining

This study is focused on developing and fabricating ball micro end mills with spiral blades by using low speed wire electrical discharge machining (LS-WEDM). Firstly, the new type ball micro end mill is designed and the mathematical model of wire movement trajectory is established for optimizing machining parameters and realizing visual prediction. Then, the diameter, spiral width, and the length consistent accuracy of ball micro end mills fabricated by LS-WEDM is investigated in detail, and more importantly, the three-spiral blades ball micro end mill with the diameter of about 278 μm and the length of 1860 μm is firstly and efficiently manufactured by LS-WEDM. Besides, the micro machining performance and tool wear of LS-WEDM fabricated ball micro end mill are evaluated by conducting micro milling experiments on nickel-based single-crystal superalloy DD5 material, and experimental results revealed that the main tool wear of the new type ball micro end mill is friction wear and adhesion wear rather than diffusion wear. Furthermore, the surface roughness of machined surface can be reduced to 183 nm, which indicates that the ball micro end mills with spiral blades fabricated by LS-WEDM are significantly potential to achieve high-quality machining for complex micro structures on hard material.