Papers by Keyword: Surface Finish

Abstract: In the existing literature, the effect of various process parameters of Bore Honing on some of the quality characteristic has been reported, but the information as to how these parameters interact with each other during the operation is inadequate. Therefore, it is required to study the combined effect of the input process parameters on the performance of honing operation in order to develop parametric relationships. In the present paper, parametric relationships have been developed between three input process parameters namely, Reciprocating Speed, Over-run, and Rotational speed and three response parameters i.e. Taper, Out of Roundness, and Surface finish by the application of Response surface methodology (RSM). Strong interaction was observed between various input parameter while affecting the performance of the process. The study of response surfaces revealed some interesting facts about Bore Honing Process.

Abstract: This paper presents a study on relationship of cooling rates towards the intermetallic compound (IMC) morphology. Cooling rate is an important parameter as it has significant effect towards the IMC microstructure formation that indirectly affects solders joint reliability. However, there is still insufficient study regarding the effect of cooling rate on the IMC thickness and microstructure behavior by using Nickel Boron as surface finish material in the electronic packaging industry. In this study, Sn-3Ag-0.5Cu solder was used on Nickel Boron as coating layer. Cooling rates were obtained by cooling specimens in different media which is water and air. The elemental composition was confirmed using Energy-dispersive X-ray spectroscopy and the microstructure of each IMC then analyzed using optical microscope, image analyzer and ImageJ. In this study, faster cooling rate (water) found to provide thicker IMC (6μm) compared to the other medium used. The morphology shape of each IMC also differs between different medium of cooling. IMC that undergoes faster cooling showed continues like layer while the one using air cooling formed scallop like IMC.

Abstract: Polishing of core and cavity surfaces after machining is a vital operation in the processing of plastic and metal cast products. It is carried out in order to achieve a certain degreeof surfacefinish-roughness or smoothness-on the machined surface, depending on its application as an end product and also for release from the cavities during ejection of the parts after moulding. Polishing is a high skilled manual time-consuming process in the overall cycle time of mould manufacturing. In this study, a CNC toolpath is generated in order to polish the core and cavity on the same machine where it is machined initially. The machine parameters for the polishing of the surfaces are optimized through a DOE set up. The surface finish achieved through machine polishing is inspected and recorded using a surface roughness tester and toolmaker’s microscope. It is observed, through the study that a combination of higher interference values between the tool face and the surface being polished along with higher feed rates proved to be determining factors in providing better surface finishes as high as 0.5μ Ra in machine polishing.

Abstract: This research was carried out as part of project MPO FR - TI4/332 – New Technologies of Bonded Facade Cladding with Anchor Elements with Increased Resistance to Corrosion.This contribution concerns tests carried out to investigate the tensile properties of silicone sealants for use with facade cladding materials. The experimental part of the research is aimed at ascertaining the technical properties of sealants via the cyclic alternation of extension and compression of test specimens in test moulds. For the tests, industrially manufactured neutral and universal silicones were chosen from three different manufacturers. The aim of the research was to discover any differences that might appear in their resistance against alternating maintained extension and compression of the specimens under extreme temperature conditions, i.e. a high temperature of (70+2) °C and a temperature simulating freezing, i.e. (-20+2) °C. The cladding material used was fibre-cement composite boards (known as Cembonit), ceramic and glass cement facade claddings.The result of the measurements taken is a summary in which effective and unsuitable combinations of sealants and test substrates are outlined. The main conclusion is the fact that it is not possible to responsibly choose a suitable material without taking appropriate measurements or having previous experience. A secondary conclusion to this article is the fact that there are significant differences between individual sealants in the results they provide in combination with specific cladding material.

Abstract: This paper describes an influence of the cutting atmosphere and the carbon content on the surface roughness and tool wear in CO₂-blow cutting of carbon steel with a diamond tool. The cutting tests were carried out by changing the cutting atmosphere and carbon contains in order to investigate the effect on the improvement of surface finish and the reduction of tool wear. The results indicated that the roughness on finished surface was improved by cutting in CO₂ gas blow atmosphere and the tool wear increased with a decrease in the carbon content.

Abstract: Products such as parts of die sets and cutting tool inserts are normally produced with complex shapes in materials of high hardness and wear resistance such as ceramics. Electro discharge machining (EDM) can be used to manufacture complex shapes in high hardness materials, but the material should be conductive. Being conductive, Aluminum oxide (Al₂O₃) based ceramics represent a good alternative for manufacturing hard complex shape parts. However, the integrity of the produced surfaces and the material removal rate need to be investigated. A full factorial experimental design was used to investigate the effect of some selected process variables, namely; pulse-on time, pulse-off time, and pulse current on specific EDM performance measures. The considered performance measures are; crater diameter (D), material removal rate (MRR), and average roughness value (Ra). An analysis of variance (ANOVA) test was carried out to evaluate the experimental results. Empirical models have been developed using DESIGN EXPERT V.8 to predict the average crater diameter (D), material removal rate (MMR), and average roughness value (Ra). Machining conditions that should result in optimum process performance measures have also been considered.

Abstract: The influence of Zwitterionic - propanesulfonate surfactant on the surface properties such as surface roughness, surface morphology and microhardness of Ni-B coatings using electroless alkaline bath was reported in this paper. Ni-B deposits obtained from nickel chloride as the source of nickel and borohydride as the reducing agent at a pH of 11 and 12 and temperature 85 ± 2 ^OC. This study reveals that the Ni – B coatings were clearly influenced by the addition of surfactant propanesulfonate on surface roughness and surface morphology. Electroless nickel (EN) - B coatings with addition of surfactant has changed the surface morphology from non-smooth nodular appearance to a smooth surface with average roughness value 1.4μm, which is less than the R_a value of without surfactant 1.98μm. The hardness of the deposit increased with lesser concentration of the surfactant when compared to without surfactant addition. Surface morphology and composition of the Ni–B coatings was analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD).

Abstract: This paper investigates the relationship of process parameters in wire electrical discharge machining of titanium alloy with brass wire as tool electrode. Wire electrical discharge machining (WEDM) is used to cut conductive metals of any hardness or that difficult to cut with conventional methods. The process performances such as material removal rate (MRR) and surface finish (R_a) were evaluated by giving specific input parameters which practiced to obtain optimal response. The difficulty in machine tool industry is to predict the expected output performance for the desired input variables by the way of conducting more number of experiments for different machining parameters, which leads to the increase in consumption of electric power, material and time. To overcome this phenomenon, parametric investigation was made on WED machining on titanium alloy by using Taguchi’s method.

Abstract: On-line monitoring systems eliminate the need for post-process evaluation, reduce production time and costs, and enhance automation of the process. The cutting forces, mechanical vibration and acoustic emission signals obtained using dynamometer, accelerometer, and acoustic emission sensors respectively have been extensively used to monitor several aspects of the cutting processes in automated machining operations. Notwithstanding, determining the optimum selection of on-line signals is crucial to enhancing system optimization requiring a low computational load yet effective prediction of cutting process parameters. This study assess the contribution of three types of signals for the on-line monitoring and diagnosis of the surface finish (Ra) in automated taper turning operations. Systems design were based on predictive models obtained from regression analysis and artificial neural networks, involving numerical parameters that characterize cutting force signals (F_x, F_y, F_z), mechanical vibration (a_x, a_y, a_z), and acoustic emission (EA_RMS).

Abstract: The demand of carbon fiber reinforced plastics (CFRP) has been increased in aircraft and automobile industries. In milling of CFRP, the cutting parameters should be determined to finish the machining surfaces without delamination. The tool wear is also a critical issue to finish good surfaces. The paper presents a force model to study the milling process of CFRP. In order to investigate the anisotropy in milling of CFRP, the cutting tests were conducted for unidirectional CFRPs with changing the feed direction of the milling tool. The cutting force and the surface finish depend on the feed direction with respect to the fiber orientation. A force model based on the minimum cutting energy is applied to milling of CFRP. The orthogonal cutting data used in the force model is associated with the relative angle of the cutting edge rotation angle to the fiber orientation. The model was verified in comparison between the predicted and the measured cutting forces. The model also estimates the effect of the feed direction with respect to the fiber orientations on the cutting force in terms of anisotropy in the orthogonal cutting data.