Rheological characterization of styrene-butadiene based medium and its finishing performance using rotational abrasive flow finishing process

摘要

Finishing of complex shaped components needs advanced finishing processes to produce nano level surface finish. Abrasive flow finishing (AFF) process uses abrasive mixed polymer as a medium to finish complex shapes. The medium should possess three basic properties i.e., better flow ability, self deformability and abrading ability to finish the given surface to nano scale. Various flow and deformation properties of the medium can be investigated by rheological characterization. In the present work, different media are made using specially co-polymered soft styrene butadiene based polymer, plasticizer and abrasives. Static and dynamic rheological properties of these in-house prepared media are evaluated, and it is found that these media follow viscoelastic behavior with shear thinning nature. For a small rise in temperature, the medium starts losing its original properties. In the present work, static (flow test, creep compliance test, stress relaxation test) and dynamic (amplitude sweep and frequency sweep) rheological properties are measured. Finishing experiments are carried out on Al alloy as well as its metal matrix composites using rotational abrasive flow finishing (R-AFF) process. Later, the effect of each rheological parameter such as shear stress, % viscous component, stress relaxation modulus and storage modulus on the change in average surface roughness (ΔR_a) and material removal rate during R-AFF is found.