Elucidating the Rheological Effect of Gel Abrasives in Magnetic Abrasive Finishing

Abstract

Toy clays made by bean gums or silicone gels can not only deform easily but also attach the undulate surface very closely. Flexible grinding tool can be produced to polish the un-flat surface by using above clays as abrasive media. Therefore, novel gel abrasives with permeability were developed to carry out magnetic abrasive finishing (MAF). In this study, bean gums or silicone gel with different viscosities were binding the steel grit and silicon carbon as gel abrasive with permeability. Magnetic finishing with gel abrasive (MFGA) was utilized in this study to polish the cylindrical rod of mold steel; furthermore, this cylindrical rod was fixed in a horizontal chuck that could rotate and vibrate in the axial direction. This study focused on the finishing efficiencies and the surface roughness of the workpieces after MFGA. Moreover, recycling times of gel abrasive were also the main effects that need to be approved. The results demonstrated that gel abrasive made by silicone gel with high viscosity would flowed away from the working area by centrifugal forces from rotating rod, inducing unstable efficiency in MFGA. However, gel abrasive produced by bean gum could resist centrifugal force and fixed in the working area, providing excellent polishing effect; therefore, surface roughness of cylindrical rod reduced from 0.65 mRa to 0.09 mRa within 5 minutes. Roughness improvement rate still remained at a high level of 90% when silicone gel with low viscosity (35 grams) was used 8 times to finish 8 workpieces, therefore, this result proved that the gel abrasive had excellent ability of the recycling.

Interplay of Process Variables in Magnetic Abrasive Finishing of AISI 1018 Steel Using SiC and Al2O3 Abrasives

“…The mechanical properties of the workpiece are shown in Table 2. Unbonded mixtures (i.e., dry mixture) of abrasive and magnetic powders were shown to be less effective in removing material during MAF [4,19]. On the other hand, solid permanent bonded abrasive material in the magnetic powder mixture works as a grinding grit, often causing fracture, non-uniform material removal, and uneven surface.…”