共查询到20条相似文献,搜索用时 15 毫秒
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Fred L. Amorim Armin Lohrengel Norbert Müller Guenter Schäfer Tiago Czelusniak 《The International Journal of Advanced Manufacturing Technology》2013,65(9-12):1423-1428
Electrical discharge machining (EDM) is a nonconventional machining process widely applied for the manufacture of intricate shapes in hard materials which are not easily machined by conventional machining processes. The production of geometrically complex EDM electrodes is difficult, time consuming, and it can account for about 50 % of the total process costs. Selective laser sintering (SLS) can be an alternative technique to produce EDM electrodes in a faster way. This work conducted an experimental study on the performance of EDM electrodes made by SLS using pure copper, bronze–nickel alloy, copper/bronze–nickel alloy, and steel alloy powders. Important EDM performance measures such as material removal rate and volumetric relative wear were investigated and discussed for finishing, semifinish, and roughing regimes. This work contributes with an insight into the production of EDM electrodes via selective laser sintering, as an alternative technique to conventional machining processes, as well as to evaluate the performance of the electrodes, and also provide directions for future research on this field. 相似文献
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P. S. Pa 《The International Journal of Advanced Manufacturing Technology》2008,35(11-12):1113-1123
In most manufacturing systems the contribution of human labour remains a vital element that affects overall performance and output. Workers’ individual performance is known to be a product of personal attitudes towards work. However, in current system design processes, worker performance variability is assumed to be largely insignificant and the potential impact of worker attitudes is ignored. This paper describes a field study that investigated the extent to which workers’ production task cycle times vary and the degree to which such variations are associated with attitude differences. Results show that worker performance varies significantly, much more than is assumed by contemporary manufacturing system designers and that this appears to be due to production task characteristics. The findings of this research and their implications are discussed. 相似文献
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Optimal parameter settings for rough and finish machining of die steels in powder-mixed EDM 总被引:1,自引:1,他引:0
Anirban Bhattacharya Ajay Batish Gurmail Singh V. K. Singla 《The International Journal of Advanced Manufacturing Technology》2012,61(5-8):537-548
The present study was undertaken to identify the appropriate parameter settings for rough and finish machined surface for EN31, H11, and high carbon high chromium (HCHCr) die steel materials in a powder-mixed electric discharge machining process. The effect of seven different process variables along with some of their interactions was evaluated using a dummy-treated experimental design and analysis of variance. Material removal rate (MRR), tool wear rate, and surface finish were measured after each trial and analyzed. The parameter settings for rough and finished machining operations were obtained. EN31 exhibited maximum MRR as compared to the other two materials at similar process settings. Copper (Cu) electrode with aluminum suspended in the dielectric maximized the MRR. Suspending powder in the dielectric resulted in surface modification. Graphite powder showed a lower MRR but improved the surface finish. HCHCr require higher current and pulse on settings for initiating a machining cut and works best in combination with tungsten–Cu electrode and graphite powder for improved finish. The MRR for H11 is lower than EN31 but significantly higher than HCHCr under same process conditions. 相似文献
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A study on helical surface generated by the primary peripheral surfaces of ring tool 总被引:1,自引:1,他引:0
S. Berbinschi V. Teodor N. Oancea 《The International Journal of Advanced Manufacturing Technology》2012,61(1-4):15-24
Often in the engineering practice, cutting tools bounded by primary peripheral surfaces of revolution are used because of their effectiveness. Among these, ring and tangential tools can be used for the generation of constant pitch cylindrical helical surfaces. In this paper, we present an algorithm for the profiling of these types of tools. The algorithm is based on the topological representation of the tool’s primary peripheral surface. The main goal is to devise a methodology for the profiling of tools whose surfaces are reciprocally enveloping with cylindrical helical surfaces. We present a numerical example for the numerical determination of the axial section form for this type of tools. The application method for this algorithm was developed in the CATIA graphical design environment within which the procedure is developed as a vertical application. In addition, we present a solution for the shape correction of the tool’s axial cross-section by considering the existence of singular points on the profile of the helical surface to be generated where multiple normals to the surface exist. 相似文献
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电火花加工变质层对模具成形表面的影响 总被引:1,自引:0,他引:1
电火花加工是模具制造的主要加工手段之一,其物理本质决定了用该手段加工的模具成形表面存在表面变质层.分析表面变质层的形成机理、变质层对模具质量和寿命的影响,并提出对策. 相似文献
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Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system's dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error(DTE) fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system's dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously. 相似文献
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Biing Hwa Yan Kun Ling Wu Fuang Yuan Huang Chun Chieh Hsu 《The International Journal of Advanced Manufacturing Technology》2007,34(1-2):96-103
In order to achieve a mirror-like workpiece surface by EDM, a micro-energy EDM or a manual lapping is normally used. However,
both methods are time consuming and economically unattractive. To have better performance, a sinking EDM machine was first
used in this research on SKD 61 for a micro-energy discharge process followed by the electrophoretic deposition (EPD) process
to coat Al2O3 particles uniformly on a rotation electrode. The precision polishing process was then applied on the discharged workpiece
with suitable parameters including the voltage, electrode rotating speed, pH value of electrolyte, and abrasive concentration.
After the EDM process, the surface roughness and the recast layer thickness of a workpiece could also be reduced. The experimental
data showed that when 0.3 μm of Al2O3 particles was used for the EPD polishing process, the initial roughness of a discharge surface could be improved from 0.52 μm
Ra (6.50 μm Rt) to a mirror-like surface of 0.068 μm Ra (0.742 μm Rt). Also, the total working time could be reduced significantly
to within the range of 5 to 10 min. 相似文献
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T.A. Spedding 《Tribology International》1996,29(3):241-249
In recent years one of the most significant developments in surface metrology has been the three-dimensional characterization of engineering surfaces. The impetus for this development was primarily motivated by a need for a more realistic visualization of surfaces than the traditional two-dimensional surface profile could provide. There have been several approaches to three-dimensional characterization of engineering surfaces including using time series and fractals. A significant application of these mathematical models would be to use them as the basis for the animation of the evolutionary changes of the surface with wear. By considering simple wear models, this paper demonstrates how computer animation illustrating the evolution of a three-dimensional surface with wear may be realized. Non-Gaussian fractals and time series are used as the basis for three-dimensional characterization and the animation is achieved using the standard morphing techniques provided by Autodesk 3D Studio. 相似文献
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Qiang Yang Zhongliang Lu Jiangping Zhou Kai Miao Dichen Li 《The International Journal of Advanced Manufacturing Technology》2017,93(5-8):1537-1544
Stereolithography apparatus (SLA) is one of the most famous and versatile additive manufacturing techniques and has been widely used in many industrial fields. However, the surface quality of SLA parts is unsatisfactory for the precise parts due to stair stepping caused by the layered manufacturing process. In this study, the stair stepping of SLA parts was relieved by ultrahigh pressure atomizing coating with the polyethylene wax emulsion using a group of optimum coating parameters. The experimental results showed that polyethylene wax film with the thickness less than 0.1 mm bonded to the SLA parts adequately and the surface roughness of the SLA parts can be significantly reduced; the Ra of SLA parts was decreased to less than 2.5 μm. This method can be applied to improve both the outer surface and the inner surface of complex SLA parts with good dimensional accuracy and no damage to SLA parts, implying potential for fabrication of precise components. Expected advantages of this method include economical, operator-friendly, and time-saving for the manufacturers. 相似文献
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Hasan Öktem Tuncay Erzurumlu Mustafa Çöl 《The International Journal of Advanced Manufacturing Technology》2006,28(7-8):694-700
The objective of this paper is to develop a Taguchi optimization method for low surface roughness in terms of process parameters
when milling the mold surfaces of 7075-T6 aluminum material. Considering the process parameters of feed, cutting speed, axial-radial
depth of cut, and machining tolerance, a series of milling experiments were performed to measure the roughness data. A regression
analysis was applied to determine the fitness of data used in the Taguchi optimization method using milling experiments based
on a full factorial design. Taguchi orthogonal arrays, signal-to-noise (S/N) ratio, and analysis of variance (ANOVA) are used
to find the optimal levels and the effect of the process parameters on surface roughness. A confirmation experiment with the
optimal levels of process parameters was carried out in order to demonstrate the effectiveness of the Taguchi method. It can
be concluded that Taguchi method is very suitable in solving the surface quality problem of mold surfaces. 相似文献
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研究了1种在普通电火花加工机床上实现金属工件表面改性的新方法。它是在传统电火花加工方法的基础上,采用WC烧结体电极和普通煤油工作液,在工件表面形成1层硬质陶瓷层,从而达到改善工件表面性能的目的。系统地对放电沉积原理进行了探讨,在大量试验的基础上,总结了放电沉积的工艺方法。通过扫描电镜、电子探针、X射线衍射分析、摩擦磨损等一系列试验手段,对形成的沉积层特性进行了定量和定性的分析。试验与分析表明,用电火花加工的方法进行表面处理是1种极具潜力的改性方法。 相似文献
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Non-contact methods are ideal for in-process monitoring of surface finish. In this context, the application of microwave reflection for the assessment of roughness assumes significance. It is well known that surface roughness affects the reflection of microwaves, and the energy loss in their transmission is considerably influenced by the finish of the wave guides. Experimental investigations were conducted with a sweep oscillator and reflectometer to find the feasibility of this technique in monitoring the roughness of manufactured surfaces. A number of surface specimens produced with different machining operations were measured for the return loss, and these compared with the normal roughness values. This paper deals with the experiments conducted and results obtained in these investigations. 相似文献
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C. Bohosievici 《Precision Engineering》1986,8(1)
The power spectral densities (psd) of surface profiles of milled steel samples have been determined by analogue measurement techniques, ie by a spectral analyser. The recorded psd curves indicate the presence in the surface profiles of some periodic components. Increase of cutting speed during milling causes the spectral density values to decrease. By psd measurement it was possible: to distinguish between surface profiles with the same Ra value, but milled under different cutting conditions; and to detect axial run-out of the milling cutter, which results in waviness of machined surfaces. 相似文献
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