Papers by Keyword: Surface Roughness (SR)

Abstract: In this paper, the effect of metal-to-metal contact from the application of plant-based lubricants, RBD palm olein and jatropa were investigated by cold work forward plane strain extrusion experiments. A pair of taper die and a symmetrical workpiece (billet) was placed inside extrusion rig which acted as main experimental apparatus. The billet material was annealed pure aluminum A1100 with radius 5 mm in deformation area. The experimental result shows that the lower viscosity index, will lead to lower friction effect to the deformed area, as well as product area.

Abstract: Magnetic abrasive finishing (MAF) is a fast and high-precision polishing method. However, the magnetic force acting on abrasive particles will decrease remarkably when polishing stainless steel tubes with the property of non-permeability, such as the SUS304 stainless steel. Moreover, the abrasive particles will be moved off the surface of machining area due to the centrifugal force of rotation, resulting in reducing the stability of polishing process. Therefore, this study developed a novel approach by adopting different gels as the bonding materials to combine the magnetic abrasive particles with hard abrasive particles to create a series of magnetic abrasive gels. Generally, those abrasive gels have higher viscosity to dominate the flow property that will constrain uniform motion of the abrasive particles in MAF, and the abrasive gels can be tightly contacted to the wall surface to increase the stability of polishing. This investigation utilized the optimal parameters out of Taguchi method to polish SUS304 stainless steel tube for 30 minutes—the value of surface roughness can be reduced from 0.636μm Ra to 0.05μm Ra, which can be improved by 92.1%, and the amount of material remove rate is as high as 218.4mg.

Abstract: The environment issue and green machining technique have been induced intensive attention in recent years. It is urgently need to develop a new kind dielectric to meet the requirements for industrial applications. The aim of this study is to develop a novel dielectric using gas media immersed in deionized water for electrical discharge machining (EDM). The developed machining medium for EDM can fulfill the environmentally friendly issue and satisfy the demand of high machining performance. The experiments were conducted by this developed medium to investigate the effects of machining parameters on machining characteristics in terms of material removal rate (MRR) and surface roughness. The developed EDM medium revealed the potential to obtain a stabilizing progress with excellent machining performance and environmentally friendly feature.

Abstract: Wire electrical discharge machining is a machining method by which parts having various contours could be detached from plate workpieces. The method uses the electrical discharges developed between the workpiece and the wire tool electrode found in an axial motion, when in the work zone a dielectric fluid is recirculated. In order to highlight the influence exerted by some input process factors on the surface roughness parameter Ra in case of a workpiece made of an alloyed steel, a factorial experiment with six independent variables at two variation levels was designed and materialized. As input factors, one used the workpiece thickness, pulse on time, pulse off-time, wire axial tensile force, current intensity average amplitude defined by setting button position and travelling wire electrode speed. By mathematical processing of the experimental results, empirical models were established. Om the base of a power type empirical model, graphical representations aiming to highlight the influence of some input factors on the surface roughness parameter Ra were achieved. The power type empirical model facilitated establishing of order of factors able to exert influence on the surface roughness parameter Ra at wire electrical discharge machining.

Abstract: This work suggests some possibilities of determination of cutting conditions for the cutting process.The most important factors affecting the surface roughness of machined sourfaces are the cutting parameters. It was shown in the paper the influence of finishing cutting regimes, for a given geometry of insert, on surface roughness of turned surfaces on CNC lathe, with higher cutting speeds than those used on conventional machine tools and with very small advances and cutting depths, thus explaining certain phenomena that occur in the cutting process.

Abstract: In general, the thin fluid film problems are explained by the classical Reynolds equation, but this approach has some limitations. To overcome them, the method of Computational Fluid Dynamics (CFD) is used in this study, as an alternative to solving the Reynolds equation. The characteristics of the two cylinders contact with real surface roughness are investigated. The CFD model has been used to simulate the behavior of the fluid flows at the conjunction between two different radius cylinders. The non-Newtonian fluid is employed to calculate the lubricant viscosity, and the thermal effect is also considered in the evaluation of the lubricant properties. The pressure distributions, the fluid film thickness and the temperature distributions are investigated. The obtained results show clearly the significance of the surface roughness on the lubricant flow at the contact center area. The fluctuated flow also affects the pressure distribution, the temperature and the lubricant viscosity in a similar pattern to the rough surface profile. The surface roughness effect will decrease when the film thickness is increased.

Abstract: A number of different mechanisms and devices may involve sliding-friction surfaces. The issues of service life and its prediction for the details of such surfaces have always been of particular importance. The article determines the most suitable wear calculation model that allows considering the set of parameters necessary for calculating slide-friction pair. The offered model is based on the application of the theories of several branches of sciences. Since the wear process is variable and many-sided, it is influenced by numerous different parameters, for example, surface geometry (roughness, waviness, form deviation, etc.), physical and mechanical conditions of the upper layer, material components, wear regime, wear temperature, etc.

Abstract: Burnishing hard materials can be used as an alternative finishing process. This paper presents the results of burnishing hardened steel. The article discusses surface deformation that occurs during this process and depends on the selected parameters of the geometric structure of the force applied for surface burnishing.

Abstract: The machining ability of Electrical Discharge Machining (EDM) die-sinking on material characteristics of LM6 (Al-Sil2) is studied. This is due to the machining process on sharp edge, pocket, deep slot and micro hole cannot be performed by milling and turning machine. The objective of this paper is to determine the relationship between the machining parameters such as pulse on time, pulse off time, peak current and voltage on material removal rate (MRR) that are electrode wear rate (EWR) and surface roughness (Ra). Graphite tool of diameter 15mm was chosen as an electrode. Taguchi method is used as analysis technique to develop experimental matrix that is used to optimize the MRR, EWR and Ra. The analysis was done by using the Minitab software version 16. It is found that the current and pulse off time are significantly effected the MRR, EWR and Ra while pulse on time and voltage are less significant factors that affected the responses. From the Taguchi method, the best setting of optimum value was obtained. Thus, it shows that Taguchi method is the best quality tools that can be applied for production.

Abstract: This research aims to determine the effect of ceramic substrates surface roughness on the deposition of silver-titania (AgTiO₂) coating. The ceramic substrates were prepared from three batch mixture of waste glass namely transparent glass (99 wt. %): carbon black (1 wt. %), green glass (85 wt. %): ball clay (15 wt. %) and transparent glass (85 wt. %): ball clay (15 wt. %) deposited with AgTiO₂ using sol gel dip coating method. Ti and Ag phases have been identified via glancing angle X-Ray diffraction analysis (GAXRD). The thickness and morphology of coatings were characterized using Scanning Electron Microscopy (SEM). Analyses conducted have confirmed that AgTiO₂ coating layers have been successfully deposited into various types of selected ceramic substrates. Microstructure analysis shows that coatings deposited on ceramic substrate with a moderate surface roughness of 2.13 (green glass: ball clay) produced the most homogeneous surface and uniform thickness.