Ultrasonic assisted electrochemical drilling and grinding of small holes on SLMed Hastelloy X with rotating abrasive tube electrode

To enhance the precision of machining small hole structures in parts produced by Selective Laser Melting (SLM), a new method named ultrasonic assisted electrochemical drilling and grinding (UA-ECDG) technology with coated abrasive tube electrode is proposed. Compared with traditional electrochemical drilling, this method has obvious advantages. Firstly, the use of tube electrode to actively spray electrolyte improves the efficiency of electrolyte renewal and machining products elimination. Secondly, through the establishment of grinding force control model, the grinding effect of abrasive coating is matched with electrochemical removal to remove passivation film with minimal damage on substrate, which can improve machining efficiency and localization while ensuring the surface quality. Thirdly, following simulation guidance, ultrasonic vibration is implemented to further optimize the grinding effect and flow field. The periodic vibration disturbs the flow field and reduces the probability of substrate damage caused by long-term contact of abrasive particles. Moreover, machining experiments were also conducted on machining parameters to obtain better machining results. Finally, small hole arrays with diameters of 1350 +/- 10 mu m and side wall roughness of 0.65 mu m were obtained on a 2-mm-thick SLMed Hastelloy X workpiece, and the side walls of small holes were vertical and smooth, demonstrating the practicality of the method.