Equipment Design And Experimental Reach Of Pulse Electrochemical Reaming Long Slender Holes

Slender holes are widely used in the field of automobile industry as well as aviation, aerospace. At present, mechanical processing method is the principal method to process slender holes, but many problems exit in this method. For example, the tool is short of rigidity and machining axis is skewed. Specially, hard-brittle material such as hardened steel and stainless steel, slender ladder holes and slender variable diameter holes are almost not processable by mechanical methods. There exist no mechanical forces in pulse electrochemical bearizing processing, so machining electrodes will no deform, burrs and stresses don’t exit on the surfaces, the machining accuracy and surface quality is good. So pulse electrochemical bearizing processing technology is suitable for processing slender holes.The characteristic of the workpiece with long slender hole is analyzed. The pulse electrochemical bearizing machining equipment for slender holes is built, including a processing device, a electrolyte system, a power source and a drive control system. The processing method of the equipment is cathode fixed and workpiece rotating and feeding. Repetitive positioning accuracy can be up to±0.5μm because high-accuracy stainless steel sliding tables are equipped. The drive control of feed system is based on PLC so different processing requirements will be met by programming. Dynamic seal is adopted in the equipment to ensure the processing region well sealed when the workpiece rotating and moving. Additionally, the cathode, electrolyte circulation system and power source are specially designed for the240mm long slender ladder holes bearizing.Conducted pulse electrochemical bearizing experiment based on the completed equipment, and analyzed the influence of the processing current density i, pulse frequency f and duty ratio D on the surface quality. When the processing current density i=8A/cm2, pulse frequency f=5kHz and the duty ratio D=40%, the workpiece can be obtained with the surface roughness Ra=0.552μm.