The Investigation On Minute Elongated Slot Based On Puncture Needle Manufactured By Micro-electrochemical Machining

With the development of products towards miniaturization, refinement andintelligence in manufacturing industry, the requirement on its dimensional precisionand surface quality are extremely strict. However, the explosive growth in demandsfor products can’t be satisfied by the traditional process technology. Hence, theelectrochemical machining, which can remove excess material by dissolving theminto ion, is highly concerned.Taking puncture needle as the research object, electrochemical machiningtechnology of minute elongated slot on the needle is studied, which realizesproduction in enormous quantities of the minute elongated slot. It is studied thatmolding precision of the minute elongated slot is measured by machining gap. In theelectrochemical machining process, Electric field based on electrolyte, thecharacteristic of electrolyte in the machining gap is changed by conduction. Thereforethe stable machining of the minute elongated slot in interstice is achieved, and themolding precision is enhanced. The researches in this thesis are shown as followed:Based on the minute elongated slot feature and the electrochemical machiningtheory, the electrochemical machining model in small gap is established. Then theinfluences on the machining gap, molding precision and surface quality, which aregenerated by flowing field and electric field, are considered and studied in themachining process. Correspondingly, the self-designed NC electrochemicalmachining facility is improved, providing the follow-up test withverification platform.The characteristics of electrolytic solution, such as electrolyte, concentration,temperature and PH, are studied to obtain their effect on machining minute elongatedslot, as well as the influence on electric field’s features in the interstice. By analyzingthe data of experiments and considering the actual production requirement, relativeparameters of electrolytic solution are optimized. To guarantee the stability ofelectrochemical machining, the electrolyte system is improved by meeting therequirement on the purity of electrolytic solution in machining gap. In order to decrease the secondary reprocessing on machined surface, the limitedgap in machining process is comprehensively investigated. In accordance with thehigh draw ratio of the slot, the features of flowing field in machining gap are analyzed.Meanwhile, the rule of processing precision is investigated by loading differentprocessing methods and feeding speed of the cathode toolFor improving the surface quality of minute elongated slot, hybrid electrolyteswith different concentrations are tested to discover how the surface quality is affectedby concentration. And the optimized parameters are verified if they can meet therequirement on dimensional precision and surface quality of minute elongated slot inactual production, after a mass of processing experiments.