Novel non-traditional mechanical drilling process with squeeze motion

High-performance micro-drilling technology for printed circuit board materials is indispensable for achieving further sophistication of electronic products. In this study, a novel mechanical drilling process, squeeze drilling (SQUD) with a non-rotating drill tool was developed. A tool with an anisotropic stiffness characteristic was designed based on the vibration mode. When the tool is excited in the axial direction, it vibrates with a squeeze motion (combined motion of translational and rotational directions) rather than rotating at ultra-high speed. Mechanical drilling through intermittent cutting can be realized simply by applying axial vibration. In addition to being able to obtain a high peripheral speed more easily than rotating the tool at high speed, SQUD can be applied to simultaneous machining of multiple points. Experimental results indicate that the process principle of the SQUD is reliable for drilling holes. Additionally, the stiffness ratio of the axial and rotational directions is important for the drilling characteristics and success.