Optimisation of grinding parameters for wheel loading and dressing
Grinding is a finishing process often used to produce desired surface roughness with required precision and quality. The performance of grinding wheel significantly depends on the nature of the wheel, morphology of the abrasive grits and the grinding parameters namely speed, feed and depth of cut. As the wheel is performing its grinding operation, its cutting surface is being loaded with metal particles of the workpiece. This wheel loading also affects the surface finish of the workpiece. Hence monitoring the grinding wheel loading and dressing at proper time intervals becomes mandatory to get the desired surface finish. In the quest of developing a low cost monitoring system, it is good enough to analyse the wheel loading on widely used metal specimens such as mild steel, HCHCr steel and aluminium under optimised cutting conditions using the conventional silicon carbide and aluminium oxide wheels for better evaluation of the results. In this work the grinding parameters are optimised by using ANOVA technique. A full factorial experiment was carried out at 5% level of significance, i.e. at 95% confidence level.
Optimization Of Process Parameters For Friction Stir W elding Of Aluminium Alloy 6061 Using Anova.
AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance. Fusion welding of aluminum alloys poses certain problems like porosity, distortion due to high thermal conductivity and solidification shrinkage. Compared to the fusion welding processes that are routinely used for joining aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. In the present work an attempt is made to study the feasibility of joining AA 6061 aluminium alloy by friction stir welding (FSW) technique. In addition ANOV A analysis with three factors is performed and results indicate that among the parameters considered (i.e., the tool rotation speed, welding speed, and the axial force), the most significant parameter on the tensile strength is rotational speed, followed by the axial force and welding speed.
Micro-injection moulding: Factors affecting the achievable aspect ratios
Micro-injection moulding is one of the key technologies for micro-manufacture because of its mass-production capability and relatively low component cost. The aspect ratios achievable in replicating micro features are one of the most important process characteristics and constitute a major manufacturing constraint in applying injection moulding in a range of micro-engineering applications. This research studies the effects of five process and one size factors on the achievable aspect ratios, and the role they play in producing micro components in different polymer materials. In particular, the following factors are considered: barrel temperature, mould temperature, injection speed, holding pressure, the existence of air evacuation and the sizes of micro features. The study revealed that the barrel temperature and the injection speed are the key factors affecting the aspect ratios of micro features replicated in PP and ABS. In case of POM, in addition to these two factors, the mould temperature is also an important factor for improving the replication capabilities of the micro-injection moulding process. For all three materials, an increase of feature sizes improves the melt flow. However, the melt fill of micro features does not increase linearly with the increase of their sizes.