Development of Novel Low-Cost Sustainable Abrasive Flow Finishing Media From Ground Tire Rubber and Its Performance Evaluation

The present experimental endeavor aims to develop and study the characteristics of a novel ground tire rubber media (GTRM) through rheological, thermal, and mechanical characterizations. Thermogravimetric analysis reveals the presence of natural and styrene butadiene rubber in ground tire rubber (GTR) and confirms the thermal stability of developed GTRM under the working temperature of the abrasive flow finishing (AFF) process. Investigation reveals that incorporating GTR into media improves AFF performance up to 50 phr, after which it degrades due to poor self-deforming characteristics and abrasive holding capacity at higher GTR fractions. It has also been observed that the percentage of oil and the size of the GTR particles are significant media parameters that govern the GTRM property and thus influence its performance. GTRM with bigger GTR produces deep abrasive cut marks and nonuniform shearing. A comprehensive study reveals that GTRM containing 50 phr GTR (80 mesh), 10% oil, and 60% SiC (220 mesh) results in the highest percentage improvement in surface roughness (% delta Ra) of 44% on flat geometry. The same media, but with coarser SiC (80 mesh), was also used to polish a micro-grooved workpiece. Results show 64% improvement in Ra for the top surface and 58% for the bottom, respectively. Both surfaces still contain a few pits and unevenness; however, the surfaces and top edge of the groove became smooth after AFF.