Study Of Improving Micro-Electrochemical Machining Accuracy By Cathode Cyclic Jump Motion

ECM (Electrochemical machining) is a special processing method which makes the part form, based on electrochemical anodic dissolution of metal in electrolyte .In machining process, anode materials removal in the form of ions. This way of removal of micro-soluble makes ECM have great potential and application prospects in micro-manufacturing fields.In micro-electrochemical machining, electrolyte refreshing and reacting products removal affect the machining stability and machining accuracy importantly. This paper carried out the experimental study of micro-electrochemical machining about cathode cyclic jump motion, which made tiny holes in engineering fields as the research object, leading in pulse power and combined with different micro-tool electrode, based on the micro-electrochemical machining device with cathode cyclic jump motion which is helpful to electrolyte refreshing and reacting products removal. Completed the following work:1. The principle of electrolyte refreshing and reacting products removal about cathode cyclic jump micro-electrochemical machining was analyzed; the mode of transporting electrolyte and reacting products were discussed. The conclusions were gained that high-speed jump of micro-tool electrode was useful to the cycle refreshing of electrolyte and reacting product removal, and electrolyte refreshing and reacting products removal in processing region would be more fully with the tool electrode jump rate increasing.2. The experimental system of cathode-cycle jump micro-electrochemical machining was improved, which contained: designing processing power on-off circuit, designing the circulatory system of large gap hydro-jet, designing of a specific control program by virtual instrument software LabView that achieved coupling control of the tools cathode movement, power and hydro-jet system, which provided a good platform for achieve more accuracy micro-electrochemical machining.3. Micro-electrodes have been made by electrochemical etching. On the basis of electrochemical etching, a new process of producing complex shapes micro-electrodes has been raised, and micro-electrodes of inverted cone-shaped have been successfully produced. The vacuum vapor deposition method was successfully used in the insulation of micro-electrode surface which was coated uniform-thickness and dense insulating film.4. The experimental study on cathode-cycle jump micro-electrochemical machining has been conducted. The experiment combined with pulse power, took self-made micro-electrode as the machining tools and stainless steel 1Cr18Ni9Ti, high-temperature alloy GH4169 as the machining objects, which studied different factors affecting machining accuracy, including electrode shapes, machining power, cathode jump acceleration, cathode jump height and different electrolytes. The results showed that: the inverted cone-shaped tool electrode, the cathode jump acceleration and the increase in jump height could achieve much higher machining accuracy; pulse power with inverted cone-shaped micro-electrode was conducive to the improvement of the depth of machining; mixed electrolyte (4%sulfuric acid+1%sodium chloride+1%citric acid) was beneficial to the machining depth of the high-temperature alloy materials.