Gr7 titanium alloy material is characterized by high strength, high plasticity, high toughness, high modulus, high damage tolerance, etc. Conventional turning and milling cannot reach the shape and size required by the design. As electrolytic machining has the advantages of short time and high efficiency, usually not subject to what kind of processing materials, therefore, it can be used as an ideal process for processing titanium alloy materials, this paper combines the practical introduction of how to use electrolytic processing to meet the design requirements of the product.
1. Design and manufacture of cathode
Due to the small size and complex shape of the products to be processed, and the need to consider the discharge gap of the electrode and the uniformity of the electrolytic flow field, the electrode needs to be designed and manufactured through the actual electrolysis test to find out the parameters. Electrode physical Figure 1 shows:
2. Processing gap
Electrolytic machining process, the smaller the discharge gap, the better the surface quality, the higher the machining accuracy, electrolytic machining, the cathode has been feeding, the anode continues to dissolve. In the process of electrolytic machining, the processing voltage and feed rate have an important impact on the processing surface quality and machining accuracy, so it is necessary to study the distribution gap. By adjusting the voltage, feed rate and selecting the appropriate electrolyte, it is possible to realize effective control of the machining gap.
3. Selection of machining electrolyte
NaCl is a strong electrolyte, which can be ionized into Na+ and Cl- ions in aqueous solution, and can coexist with H+ and OH- ions in water, NaCl electrolyte theoretically in the processing of titanium alloys, through the appropriate adjustment of the machining voltage, feed rate and optimization of the electrode structure, it will make the processing of products with better surface quality and higher precision. When NaCl is selected as the electrolyte solute, its concentration is generally controlled at 10%-14%, when the surface quality requirements are higher, it is generally controlled at less than 10%, and the processing temperature is usually controlled at , which is the 14% concentration of NaCl solution used as the electrolyte for this study. At the same time, in order to ensure the effective utilization of electrolyte.
4. Insulation isolation of non-processing surfaces
In the process of electrolytic processing, in order to protect some non-processing parts, so that it does not produce pitting corrosion, usually take some insulation protection methods. After practice, the final determination of the use of electrostatic spraying method, not only can effectively avoid the electrolyte and non-processing surface contact, play a role in isolating the stray current, and its spraying of non-metallic insulation layer is thinner, paste is also more reliable, more will not be due to the high temperature generated by electrolysis and melt off, a spraying can be used many times.
After completing the selection of electrolyte, processing parameters to determine the insulating layer of spraying and other work, combined with the necessary indexing fixture, after adjusting the alignment and other preparatory work, the formal product processing, the actual product processing results shown in Figure 2. After inspection, the actual machined dimensions can reach the precision and size required by the design. Compared with the EDM process, the machining efficiency is increased by more than 95%, which not only improves the production efficiency, but also saves the production cost, as well as a large amount of manpower and material resources, and avoids the unnecessary waste of resources. Electrolytic machining in the electrolytic processing of titanium alloy products, as long as the correct design of processing electrodes, reasonable selection of processing parameters, the appropriate preparation of processing electrolyte, the use of ideal insulation protection methods, etc., you can be a one-time short time and efficiently processed to meet the design requirements of the product.
