Papers by Keyword: Surface Roughness (SR)

Abstract: The utilization of Al/SiCp metal matrix composites in different engineering fields has undergone a tremendous increase due to its tailor-made properties that can be achieved by varying the size and volume fraction of reinforcement. However, the difficulty in machining of metal matrix composites (MMCs) arises not only from the excessive wear of the cutting tools but also from fracturing of the reinforcement particles on machined surfaces that leaves behind adhered particle fragments, pits and cavities. These characteristics in machining of MMCs tend to adversely affect the machined surface quality/integrity. Hence, some attempts are made to improve the machinability of MMCs and surface quality by hot machining using wiper inserts. Experimental results indicate that the moderate heating of Al/SiCp composite material prior to machining (60-90°C) reduces the machining forces and improves the surface quality by minimizing, debonding, fracture and pull-out of reinforcement particles from the matrix material.

Abstract: With putting the response surface methodolody and design theory into the programming of LabVIEW8.6, the process parameters optimization system is designed. The system can realize the function of test project design,online data acquisition, response surface model building and process parameters' optimization, which can greatly reduce the calculated amount of modeling and optimization. Taking 45 steel milling experiment for example, the models of surface roughness and cutting force are established by using the optimization system, taking the minimum surface roughness value as target and optimizing the process parameters, which provide practical support tools for further analysis of process parameters on the effect of processing quality

Abstract: An experimental investigation was conducted on grinding Ti-6Al-4V alloy with monolayer brazed CBN slotted wheels for detecting the performance of the newly developed tools. The results showed that the effects of grinding parameters on the grinding forces and surface roughness with the brazed wheels were similar to that obtained with conventional electroplated ones to a certain extent. However, due to some distinguished features of the brazed CBN tools, i.e., high grain protrusion, optimum grain distribution and especially high joining strength, grain premature pullout behavior that had often occurred for electroplated tools was not observed during grinding, which had significant influence on the CBN wheels with merely singer-layer grains.

Abstract: The fluid magnetic abrasive (FMA) is a new type of intelligent material. The fluid magnetic abrasive (FMA) has typical liquid characteristics, when there is no external magnetic field around it. But when a strong magnetic field is applied, the viscosity of it will increase more than 100 times within a few milliseconds, and it will show the characteristics those are resemble to solid's. We call this feature as rheological property, of which because the workpiece can be finished by fluid magnetic abrasive (FMA). On base of researching on the micro-structure of fluid magnetic abrasive (FMA), the experiments and results are presented in this paper.

Abstract: Molecular dynamic simulation for Co cluster deposition on Si substrate was investigated in this work. The surface roughness and the interface mixing will be evaluated for the deposited film quality under different incident energies and substrate temperatures. The effect of thermal annealing on the ability of gap filling will be discussed by a slip vector. The results indicate that the incident energy has dominant effect on the surface roughness, and there is a minimum surface roughness value around the incident energy of 8 eV. However, the substrate temperature has little effect on the surface roughness. For interface mixing, the simulation indicates the easy diffusion of Co atoms into Si substrate. However, increasing either the incident energy or the substrate temperature could not change much the mixing conditions. As for the ability of gap filling, it is clear that the thermal annealing does improve this ability and obtains better surface roughness and interface mixing.

Abstract: In order to analyze the relation between wood surface roughness of Laminated Veneer Lumber of Eucalyptus and sanding parameters, an orthogonal experiment and a single factor experiment were performed. The results show that the mesh of the sandpaper has remarkable influence on wood surface roughness of Laminated Veneer Lumber of Eucalyptus, but the feeding speed and sanding thickness don’t; when the mesh of the sandpaper is 150, the feeding speed is 6 m/min and sanding thickness is 0.6 mm during the first sanding and the mesh of the sandpaper is 320, the feeding speed is 9m/min and sanding thickness is 0.2mm during the second sanding, the smallest roughness (Ra) was obtained as 2.45μm. Considering production efficiency, changing feeding speed into 9 m/min, engineering optimization scheme was obtained, and the wood surface roughness (Ra) is 2.70μm.

Abstract: The cemented carbide tool and high speed steel tool are used as experimental cutting tools. The cutting properties of composite were studied by cutting lathe, tool microscope and light-section method microscope. The results show that carbide and high speed steel tool flank wear rate increase with the increasing of SiC particles size as well as the content of SiC particles. When the particles size of SiC is 40μm, composite cutting surface roughness increases with increasing of the content of SiC particles. While the particles size of SiC is 20μm, composite cutting surface roughness decreases with increasing of the content of SiC particles. In the same cutting conditions, the Carbide tolls have longer life than high-speed steel tools.

Abstract: This research evaluated the planing performance of bamboo scrimber boards at three feed speeds and three cutting depths and used two methods to assess the finished surfaces. A macroscopic grade assessment was made according to ASTM D 1666-87 for visible planing defects. The other assessment was a microscopic scale roughness test measuring surface average roughness in terms of GB/T 12472. The visible results showed that the finished surface quality of bamboo resulted mainly in Grades and , with the main defect being torn grain. The two evaluations method showed consistent results in surface quality that the highest percentage of Grade was counted and the lowest roughness value occurred. Compared with the hardwood Sawtooth oak widely used in furniture industry in China, planning quality of bamboo scrimber board is better in terms of roughness.

Abstract: In order to analyze the relation between wood surface roughness of plantation-Mytilaria laosensis and sanding parameters, two orthogonal experiment were performed. The results show that the mesh of the sandpaper has remarkable influence on wood surface roughness of plantation-Mytilaria laosensis,but the feeding speed and sanding thickness don’t; when the mesh of the sandpaper is 150, the feeding speed is 7 m/min and sanding thickness is 0.6 mm during the first sanding and the mesh of the sandpaper is 240, the feeding speed is 8m/min and sanding thickness is 0.15mm during the second sanding, the smallest roughness (Ra) was obtained as 2.79μm. Considering production efficiency, changing feeding speed into 9 m/min in the theory optimization scheme, engineering optimization scheme was obtained, and the wood surface roughness (Ra) is 2.80μm.

Abstract: Inconel 718 is used for high-temperature applications in aerospace, nuclear, and automotive industries due to its resistance, at high temperatures, to corrosion, fatigue, creep, oxidation, and deformation. Unfortunately, these same qualities also impair its machinability and researchers have investigated on ways to machine it economically. Some unconventional machining practices such as: Plasma Enhanced and Laser Assisted Machining etc. have been applied. However these practices increase the machining cost. This research investigated the viability of high speed end milling of Inconel 718 using circular Silicon Nitride (ceramic) inserts under room temperature conditions. Tool wear (flank and notch wear), machining vibration amplitude and average surface roughness were evaluated for the feasibility analysis. A vertical CNC mill was used to machine Inconel 718 samples using different combinations of three primary machining parameters: cutting speed, feed, and depth of cut. Vibration data acquisition device and Datalog DasyLab 5.6 software were used to analyze machining vibration. Scanning Electron Microscope (SEM) and surface profilometer were utilized to measure tool (flank and notch) wear and surface roughness, respectively. It was observed that the machining vibrations, in high speed machining, was reasonable (0.045 V on the average). This resulted in acceptable tool wear (averages: flank wear = 0.25 mm, notch wear = 0.45 mm) and semi-finished surface roughness (0.30 µm) measured after every 30 mm length of cut. Thus, room temperature high speed machining of Inconel 718 using circular silicon nitride inserts is a practical option.