Optimization of process parameter for surface finishing in abrasive flow finishing process
274 Optimization of process parameter for surface finishing in abrasive flow finishing process Ravi Gupta (M.E) Asst. Prof.(Lovely Professional University) raviarya43@gmail.com , Abstract-Abrasive flow finishing is a non-conventional finishing process that is used for finishing of work piece which are difficult to finish by conventional method i.e. by honing, lapping and other machining operations. It is used for polishing, deburring, removing recast layer of component and for cleaning of surfaces having complex shape and size of geometrical components. Abrasive flow finishing process polishes the surface by forcing the abrasive medium inside the work piece through the restricted area. One of the limitations of this process is that it is time consuming process and low material removal rate. To overcome these limitations, a structure has been developed. In this setup, centrifugal force has been generated by using a tool rod inside the hollow work piece to which rpm was provided. The abrasive mesh size, abrasive concentration, number of cycle, extrusion pressure, rotational speed of CFG rod, diameter of tool rod and shape of tool rod are the some important process parameter which affects the surface quality. In this research paper, the role of abrasive mesh size, extrusion pressure, abrasive concentration and rotational speed has been discussed on Gun metal as material of work piece. For experimentation design, taguchi approach L9 orthogonal array has been used and for analysis of result, ANOVA has been performed. KeywordsAFF, Surface roughness, rotational speed Taguchi method, ANOVA
Enhancing AFM process productivity through improved fixturing
Abrasive flow machining (AFM) is a non-conventional finishing process that deburrs and polishes by forcing an abrasive laden media across the workpiece surface. The process embraces a wide range of applications from critical aerospace and medical components to high-production volumes of parts. One serious limitation of this process is its low productivity in terms of rate of improvement in surface roughness. Limited efforts have hitherto been directed towards enhancing the productivity of this process with regard to better quality of workpiece surface. This paper discusses improved fixturing as a technique for productivity enhancement in terms of surface roughness (Ra). A rotating centrifugal-force-generating (CFG) rod is used inside the cylindrical workpiece which provides the centrifugal force to the abrasive particles normal to the axis of workpiece. The effect of the key parameters on the performance of process has been studied. The results shows that for a given improvement in Ra value, the processing time can be reduced by as much as 70–80%. It is seen that the significant process parameters are revolutions per minute of CFG rod, extrusion pressure and abrasive mesh size.
Effect of Calcium Glycerophosphate on Demineralization in an in vitro Biofilm Model
The aim was to investigate the anti-caries properties of calcium glycerophosphate (CaGP) using an in vitro bacterial flow cell model. Four flow cells, inoculated from a chemostat containing a seven-organism bacterial consortium, were pulsed with sucrose twice daily, to provide an acidic challenge and pH-cycling conditions. Blocks of enamel and dentine were mounted in each flow cell. In a study on the effect of CaGP concentration, CaGP was pulsed into three of the flow cells, at the same time as the sucrose, to give concentrations of 0.10, 0.25 and 0.50%. Water was pulsed into the fourth flow cell with the sucrose. Microradiography revealed a significant dose response of decreasing demineralization as CaGP concentration increased. Reductions at 0.25 and 0.5% were significant when compared to the control. A second study investigated the effect of timing of CaGP pulsing, relative to sucrose, on enamel and dentine demineralization. CaGP (flow cell concentration 0.2%), was pulsed 1 h before, during or 1 h after the sucrose pulse; a water control was employed. In enamel, pulsing CaGP before the sucrose reduced demineralization significantly compared to concurrent pulsing, which in turn gave a significant reduction compared to pulsing after sucrose, which did not reduce demineralization significantly compared to the water control. In dentine, CaGP reduced demineralization significantly only when pulsed before the sucrose. The findings suggest that in vivo, the anti-caries potential of CaGP may be greater if it is applied before a cariogenic challenge.