High-quality machining of thin copper plate based on error proofing method

Abstract

The response characteristics of target materials under dynamic compression have been a focused topic in the fields of shock wave physics and explosion dynamics. Thin copper plate with high-quality surface is frequently applied as flyer in detonation or plate impact experiments to study these characteristics. Nevertheless, existing mechanical machining method is hard to achieve high-quality surface for copper flyer due to ductile property and residual stress. To settle this problem, a technology based on error proofing is proposed to realize thinning, surface shape error control and improving surface quality in turn. Firstly, an isopotential control method is proposed in electrochemical lapping process to suppress stray current corrosion, which lays the foundation for high-efficiency low-stress thinning with MRR = 1 μm /min. Secondly, a chemical mechanical lapping method considering pressure and speed distribution is applied to control surface shape error deterministically with acceptable roughness S_a ≤ 350 nm (measure size: 0.36 mm × 0.27 mm). Then electrochemical mechanical polishing at low pressure (P = 0.27 psi) is applied to obtain surface roughness of S_a ≤ 5 nm with maintained flatness. Finally, a high-quality machining technology for thin copper plate is developed. By the low-stress machining method, copper plate (Φ100 mm × 3 mm) achieves flatness of PV 2 μm and moderate roughness S_a 4.2 nm.