Achievement of required surface roughnesses in complex profile channels by dynamic combined processing

Abstract

At present for processing of complex geometrical channels of workpieces electrochemical dimensional processing, vibro-impact machining and vibro-extruding are widely used. However combined electrochemical mechanical processing, that unites anodic dissolution and plastic flow of material in space and time, provides the required characteristics of surface layer. Local action anodic dissolution changes cold work amount and accelerates dissolution of micro- and macro-cusps, this causes annealing of physical and mechanical parameters in processed segments and accross the whole surface profile the required strengthening degree is attained. The authors examine annealing model for microsurface by grain displacement in channel where extrusion forcing is dictated by grains size and profile of narrow blade channel and also by actual processing conditions. Operating conditions that are recommended for implementation of combined electrochemical mechanical processing of impeller and turbine type workpieces are found by experiments. In consequence of field research they determined availability of standard microgeometry across the whole surface profile by combined processing with vibrations hashing with up to 2030 Hz frequency and low voltage current (in operation range from 1,2 till 1,8 V). Therein technological cycle decreases up to two fold, this reduces inadmissible jumping of blade edges and dimensional allowance.

Influence of Contact Efforts on the Surface Quality of Difficult Profile under Finishing Hardening Machining

“…Following the calculation results we find the least value of pressure (P), when the optimal degree of cold-work hardening is guaranteed. This ensures obtaining the surface without cold-work overhardening, that decreases fatigue strength [7].…”