Investigation of pulse electrochemical sawing machining of micro-inner annular groove on metallic tube

• Pulse electrochemical sawing machining of micro-inner annular groove is proposed.
• The rotating dentate cathode is beneficial for the distribution of electrolyte.
• Uniform distribution of bubbles adhered to the surface of rotating dentate cathode.
• the mathematical model of ECSM of inner annular groove was set up.
• A inner annular groove that is 340 μm in depth and 263 μm in width was fabricated.

Pulse electrochemical sawing micro-machining (PECSM) is a non-conventional process. Having features of no tool wear, no cutting force, and good surface quality, this process is suitable for machining micro-grooves on the inner wall of hole. The rotating dentate cathode (RDC) is beneficial for the distribution of electrolyte and electrolytic products removal, thus reducing the effects of concentration polarization on the electrochemical reaction. This study focuses on the PECSM of micro-inner annular groove on 304 stainless steel tube using a pH-neutral NaClO3 electrolyte. To study the effects of RDC on the process, the bubble layer structure (BLS) adhered to the surface of RDC was photographed using a high-speed camera. Under the condition of immersion, the symmetric distribution of two kinds of BLS adhered to the RDC surface. The four selected parameters (radius of dentate cathode, rotational speed of RDC, initial gap, feed rate) with different levels were carried out to study the process of PECSM micro-inner annular grooves on 304 stainless steel tube. Experimental results indicate that PECSM has high potential for machining micro-inner annular groove on metallic tube. A micro-inner annular groove that is 340 μm in depth and 263 μm in width was fabricated on a 304 stainless steel tube.