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Search Results: 1 - 10 of 242 matches for " turning "
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Burnout: Drudgery, Repetition, Creativity  [PDF]
John Y. Wu, Kuangming Wu
Open Journal of Philosophy (OJPP) , 2016, DOI: 10.4236/ojpp.2016.62020
Abstract: Identical repetition composes drudgery that results in burnout. But besides identical, there can be repetition of daily routine, and also can be continuing creative novelty. We must dissolve burnout by turning identical repetition into regular routines of creative novelty. This essay is thus composed of three sections, drudgery, repetition, and creativity.
Residual stresses modelling in hard turning and its correlation with the cutting forces
G.F. Batalha,S. Delijaicov,J.B. Aguiar,E.C. Bordinassi
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: This paper aims to study the cutting parameters influence (cutting speed, feed rate, cutting depth and tool radius nose) on the cutting forces (cutting force, feed rate cutting force and penetration cutting force) as well as on the residual stresses, in conical bearings made of steel DIN 100 CrMn6 hardened (62 HRc), searching correlations between the residual stresses and the cutting forces.Design/methodology/approach: A complete factorial planning was used to establish the correlations. At the same time, the cutting parameters influence in the microstructure of the material and it’s correlation with the residual stress was studied. A turning center machine and CBN inserts was employed for the tests. To the cutting force measurements was carried out using a piezoelectric dynamometer. The residual stresses measurements were carried out by X-ray diffractometry.Findings: The penetration cutting force was the most important factor in the residual stress generation, and it was influenced by the feed rate and the cutting depth. A correlation between the cutting depth and the residual stresses was established. The results do not showed any changes in the microstructure of the material, even when the greater cutting parameters were used.Research limitations/implications: The residual stress is one of the major causes of failures in bearings by contact fatigue, keeping this on mind, this work helps the developer to select correct cutting parameters in order to increase the machined workpiece life in service.Originality/value: This work were based on the real components (conical bearings), real cutting conditions and with these results were possible to make greater improvements in the manufacturing and in the quality of the studied parts.
Influence of Cutting Speed, Feed Rate and Bulk Texture on the Surface Finish of Nitrogen Alloyed Duplex Stainless Steels during Dry Turning  [PDF]
D. Philip Selvaraj, P. Chandramohan
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.26059
Abstract: This paper presents the results of experimental work carried out in dry turning of cast duplex stainless steels (ASTM A 995 Grade4A and ASTM A 995 Grade5A) using TiC and TiCN coated cemented carbide cutting tools. The turning tests were conducted at five different cutting speeds (80, 100, 120, 140 and 160 m/min) and three different feed rates (0.04, 0.08 and 0.12 mm/rev) with a constant depth of cut (0.5 mm). The influence of cutting speed and feed rate on the machined surface roughness was investigated. Texture analysis (Bulk) was also carried out to study the impact of preferred orientation on the resulting surface roughness. The result reveals that the increasing cutting speed decreases the surface roughness till a particular point and then increases whereas; the surface roughness value decreases with the decreasing feed rate. Presence of alpha fiber (Bulk texture analysis) in the austenite phase of 4A work piece material leads to better surface finish. Among both the grades, surface finish of grade 4A is better than grade 5A work piece material.
Multi-Objective Optimization Using Genetic Algorithms of Multi-Pass Turning Process  [PDF]
Abdelouahhab Jabri, Abdellah El Barkany, Ahmed El Khalfi
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.57072
Abstract:

In this paper we present a multi-optimization technique based on genetic algorithms to search optimal cuttings parameters such as cutting depth, feed rate and cutting speed of multi-pass turning processes. Tow objective functions are simultaneously optimized under a set of practical of machining constraints, the first objective function is cutting cost and the second one is the used tool life time. The proposed model deals multi-pass turning processes where the cutting operations are divided into multi-pass rough machining and finish machining. Results obtained from Genetic Algorithms method are presented in Pareto frontier graphic; this technique helps us in decision making process. An example is presented to illustrate the procedure of this technique.

Motor Effects of 1,3-Disubstituted 8-Styrylxanthines as A1 and A2 Adenosine-Receptor Antagonists in Rats  [PDF]
Ilhuicamina Daniel Limón-Pérez de León, María del Carmen Parra-Cid, Alejandro Mu?oz-Zurita, Saúl Alejandro Merino-Contreras, Sara Montiel-Smith, Socorro Meza-Reyes, Gerardo Ramírez-Mejía, Jesús Sandoval-Ramírez
Pharmacology & Pharmacy (PP) , 2013, DOI: 10.4236/pp.2013.43044
Abstract:

A series of 1,3-substituted 8-styrylxanthines (11a-d) was synthesized, under chemo- and regioselective conditions, in a good overall yield. The compounds showed affinity towards both A1 and A2A-adenosine receptors by radioligand binding by means of in vitro assays. The (E)-3-ethyl-1-propyl-8-styrylxanthine (11a) showed the greatest affinity towards the A2A receptor, whereas (E)-3-pentyl-1-propyl-8-styrylxanthine (11d) showed the greatest affinity for the A1 receptor. When the 8-styrylxanthines 11a (A15Et) and 11c (A15Bu) were administrated in rats, which were previously injured with 6-hydroxydopamine at the substantia nigra pars compacta (SNc), the turning behavior decreased 50%. Based on these results we propose to A15Et as a potential compound to treat some symptoms of Parkinson’s disease.

Some Preliminary Metallurgical Studies on Grain Size and Density of Work Material used in Micro Turning Operation  [PDF]
A. S. Patil, H. K. Dave, R. Balasubramaniam, K. P. Desai, H. K. Raval
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.99061
Abstract: One important process in tool based micro machining technology is CNC micro turning which has the capability to produce 3D structures on micro scale. The major drawback of micro turning process is that the machining force influences machining accuracy and the limit of machinable size and shape. Therefore, the control of reactive force during cutting is an important factor in improving machining accuracy. The properties of work material significantly affect the cutting force generated during turning process. Commercially available metal rods are inhomogeneous and hence, qualifying the right material is very crucial in micro turning. Unlike plates, the properties like grain size and density vary significantly at different locations of the round bars. Hence, it is found very important to systematically find right material for micro turning from the commercially available rods. In present study, an attempt has been made to study the grain size and density of blank material from different locations of a larger diameter shaft. The work material selected is a 32 mm diameter shaft of commercial brass, a non ferrous alloy of copper and zinc. Five samples from different radial locations are cut from this shaft. It is found that grains are coarser at centre and finer towards the periphery of the shaft. Further, local density is less at centre and high at periphery of the shaft.
Determining the Effect of Cutting Fluids on Surface Roughness in Turning AISI 1330 Alloy Steel Using Taguchi Method  [PDF]
Onyemachi Joachim Onuoha, James Oseni Abu, Sunday Albert Lawal, Edeki Mudiare, Michael Bolaji Adeyemi
Modern Mechanical Engineering (MME) , 2016, DOI: 10.4236/mme.2016.62006
Abstract: Taguchi method has been employed to investigate the effects of cutting fluids on surface roughness in turning AISI 1330 alloy steel, using manually operated lathe machine. Experiments have been conducted using L27 (34) orthogonal array and each experiment was repeated three times and each test used a new cutting tool, High Speed Steel (HSS), to ensure accurate readings of the surface roughness. The statistical methods of Signal-to-Noise (S/N) ratio and the Analysis of Variance (ANOVA) were applied to investigate effects of cutting speed, feed rate and depth of cut on surface roughness under different cutting fluids. Minitab 14 software was used to analyze the effect of variables on the surface roughness. Results obtained indicated that optimal variables for the minimum surface roughness were cutting speed of 35 m/min (level 2), feed of 0.124 mm/rev (level 1), depth of cut of 0.3 mm (level 1) and a cutting fluid with a viscosity of 2.898 mm2/s (level 3). Hence, the optimal parameters to obtain better surface roughness of the workpiece material were obtained when groundnut oil based cutting fluid was used. Analysis of variance shows that feed rate has the most significant effect on surface roughness.
Research on China’s “Lewis Turning Point” and Efficiency Analysis of Each Province—Based on DEA and SFA Methods  [PDF]
Shu Liu
Modern Economy (ME) , 2019, DOI: 10.4236/me.2019.104080
Abstract: Based on the current situation of China’s labor market, this paper studies whether China crosses the “Lewis Turning Point” in 2009-2017. Research shows that China has not yet entered the “Lewis Turning Point”. This paper uses the marginal productivity of labor as the criterion for judging the problem and calculates the capital stock through the perpetual inventory method to further estimate the production function and the marginal productivity of labor. Although China has not entered the “Lewis Turning Point”, due to the heterogeneity between cities, some cities may have entered the “Lewis Turning Point” in advance. This paper further analyzes the provinces of China and uses DEA and SFA methods to analyze the efficiency of capital stocks and labor input in various provinces. The results show that some cities are inefficient due to excessive labor input. China can transfer labor through a reasonable labor policy, thereby avoiding labor shortages in some cities and ultimately improving the efficiency of resource allocation in each province.
Performance profiling of boric acid as lubricant in machining
Damera, Nageswara Rao;Pasam, Vamsi Krishna;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2008, DOI: 10.1590/S1678-58782008000300009
Abstract: turning is a widely used metal removal process in manufacturing industry that involves generation of high cutting forces and temperature. lubrication becomes critical to minimize the effects of these forces and temperature on cutting tool and workpiece. the conventional cutting fluids employed in machining have certain limitations with regard to their use for ecological and economic reasons. development of lubricants that are eco friendly is acquiring importance. in this context, application of solid lubricants has proved to be a feasible alternative to the conventional cutting fluids. in the present work, boric acid is used as a lubricant in turning process. variations in cutting force, tool wear, tool temperature and surface roughness are studied under different machining conditions. the results indicate that there is considerable improvement in the machining performance with boric acid assisted machining compared to dry and wet machining.
EFFECT OF FEED RATE ON THE GENERATION OF SURFACE ROUGHNESS IN TURNING
M.RAMALINGA REDDY,P.RAVI KUMAR,G.KRISHNA MOHANA RAO
International Journal of Engineering Science and Technology , 2011,
Abstract: In this paper the effects of the feed rate on the generation of surface roughness in turning is analyzed. The studies include roughness profiles, their roughness indices and Fourier spectra. Since the resultant surface is basically the result of metal removal in the form of chips, additional studies include chip related phenomena such as chip morphology, direction of flow and curling of chips and morphology of machined surface. These have been studied under SEM.
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