Research on dynamic characteristic of softness consolidation abrasives in machining process

Abstract

Pneumatic wheel based on softness consolidation abrasives (SCA) is presented as a key machining tool mainly for the improvement of finishing efficiency to free-form surface of laser-hardened molds. In this case, though its softness fits for machining to free-form surface, it cannot keep all abrasives within bounds strictly, but it makes abrasives experience creep deformation, which always leads to unstable machining characteristics. For research on the working rule of SCA, dynamic characteristics of abrasives need to be investigated. Firstly, soft ball model is brought into analysis of the normal and shear contact forces between two particles. By introducing damping coefficient, formulas on displacement and velocity of SCA are given for theory analysis of creep deformation. After that, force chains are established by simulation, which proves that SCA possesses more cutting force than free abrasives. At the same time, creep deformation of SCA is confirmed in accordance with the analysis of velocity of the single particle. Subsequently, combined with the modified Preston formula, comparative machining tests on material removal are carried on a laser-hardened free-form surface. Experimental results show that material removal rate of SCA is higher than that of free abrasive by approximately 34.35 %. Moreover, abrasive size is discussed as a key parameter respectively according to consolidation effects and surface roughness. The final conclusion is that SCA is certified to improve finishing efficiency for laser-hardened surfaces as well as suitable for machining free-form surfaces.