共查询到20条相似文献,搜索用时 0 毫秒
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For stereolithography process, accuracy of prototypes is related to laser power, scan speed, scan width, scan pattern, layer
thickness, resin characteristics and etc. An accurate prototype is obtained by using appropriate process parameters. In order
to determine these parameters, the stereolithography (SLA) machine using neural network was developed and efficiency of the
developed SLA machine was compared with that of the traditional SLA. Optimum values for scan speed, hatching spacing and layer
thickness improved the surface roughness and build time for the developed SLA. 相似文献
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In the design of the roll forming process, design errors can be determined in advance by using an FE simulation tool such
as SHAPE-RF. In the case of a product such as a slide rail having a complicated shape and requiring high-precision forming,
a standard is necessary for quantitatively evaluating the quality of the formed shape. In the analysis of the roll forming
process of a slide rail, the pass having the largest deformation is designated as the target pass and the positions and shapes
of the rolls are set as design variables. A minimum number of simulations was performed by using the table of orthogonal arrays.
A cost function was obtained from the results by using the design of experiments such as the response surface method and it
was minimized for satisfying the design constraints. By improving the design of the target pass, the shape of the final product
approaches that intended by the designer. 相似文献
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Dr Leong Kah Fai Chua Chee Kai Tan Chee Hock 《The International Journal of Advanced Manufacturing Technology》1998,14(6):450-458
This paper describes an investigation of the effect of the microblasting process on the surface finish of jewellery models built using stereolithography apparatus (SLA). The layering process of SLA results in visible steps on the model surface. The investigation aims to determine the significant operating parameters of the microblaster deburring process that affect the surface roughness of the SLA jewellery model, to set a practicable range for these parameters for effective deburring and establish the optimum parameters for the best surface finish. A ring model based on the British Standards 28653: 1993 is designed using the Pro-Engineer software. The experimental strategy applies techniques including the full factorial and Yates' method together with the analysis of variance on the deburred samples. The surface roughness of the ring models before and after the deburring process are then measured with a Form Talysurf surface roughness measuring machine. The information obtained is used to identify the parameters for further study. Parameters identified are different nozzle types, blasting time and pressure variation. These parameters are tested for their optimum settings and the microblasting process is found to significantly improve the surface finish by approximately 30% on both the curvature and flat features of the ring model. 相似文献
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Huamin Zhou Dequn Li 《The International Journal of Advanced Manufacturing Technology》2006,28(1-2):53-60
Functional parts are needed for design verification testing, field trials, customer evaluation, and production planning. By
eliminating multiple steps, the creation of the injection mold directly by a rapid prototyping (RP) process holds the best
promise of reducing the time and cost needed to mold low-volume quantities of parts. The potential of this integration of
injection molding with RP has been demonstrated many times. What is missing is the fundamental understanding of how the modifications
to the mold material and RP manufacturing process impact both the mold design and the injection molding process. In addition,
numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection
molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type
of injection molds, mainly because the property of the mold material changes greatly. In this paper, an integrated approach
to accomplish a numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation
system is developed. Comparisons with experimental results are employed for verification, which show that the present scheme
is well suited to handle RP fabricated stereolithography (SL) molds. 相似文献
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S.H. Masood J.P. Singh Y. Morsi 《The International Journal of Advanced Manufacturing Technology》2005,27(3-4):415-420
This research paper addresses the issue of developing an efficient methodology to design and manufacture a complex scaffold
structure of desired porosity required for tissue engineering applications using a novel approach based on fused deposition
modelling (FDM) rapid prototyping (RP) technology. The scaffold provides a temporary biomechanical structure for cell growth
and proliferation to produce the required body parts. Conventional techniques of scaffold fabrication (such as fibre bonding,
solvent casting and melt moulding) generate scaffolds with unpredictable pore sizes due to their limitations in flexibility
and control of pore volume and distribution. Moreover, such scaffolds have poor mechanical strength and structural stability.
The paper describes an FDM pre-processor that ensures the fabrication of scaffolds of desired porosity and inter-connectivity
on the FDM system. 相似文献
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熔融挤压快速成形特殊形状产品的工艺探讨 总被引:1,自引:1,他引:0
分析熔融挤压快速成形的工艺,针对三种特殊形状产品,从支撑、台阶效应、丝料特性等几个方面探讨了成形方向选择和壁厚控制对加工质量的影响,并成功加工出结构复杂产品、片状产品和薄壁半透明产品。 相似文献
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A. Krimpenis A. Fousekis G. Vosniakos 《The International Journal of Advanced Manufacturing Technology》2005,25(5-6):444-453
Product manufacturing on CNC milling machine tools involves a number of machining parameters and tool geometries. In the case of sculptured or free-form surfaces the number of these parameters can be significantly large and vary according to surface complexity. Minimising the number of parameters is carried out through statistical elimination. Design of experiments (DoE) along with the respective statistical analysis of variance (ANOVA) constitutes a low-cost useful tool in determining sub-optimum values for all parameters involved in each milling strategy as well as the most significant of those parameters. DoE was implemented for a particular sculptured surface assessing a variety of roughing and finishing strategies of a CAM simulation software. 相似文献
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Abdur Rahim Mehmood Khan 《The International Journal of Advanced Manufacturing Technology》2007,32(7-8):747-756
This paper presents a generalized model for the optimal determination of a production run and the initial settings of the
process mean and process variance for a deteriorating production process. It is assumed that the process deteriorates due
to tool wear-out. The probability that the process deterioration starts at a random point in time follows an exponential distribution.
Quality loss from the target values is measured using Taguchi’s quadratic loss function. The time dependent maintenance cost
and the salvage value of the equipment are included. The expressions for determining the optimal process mean and process
variance are developed. Numerical examples are provided to demonstrate the application of the proposed model. 相似文献
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Chil-Chyuan Kuo Hsueh-An Liu Chao-Ming Chang 《The International Journal of Advanced Manufacturing Technology》2020,106(9):3775-3785
Vacuum casting is one of the widely used methods for small-volume production of plastic parts. The main challenge of this method is to choose the optimal w 相似文献
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利用Moldflow分析软件,采用数值模拟的方法分析了料温、模具温度、注射时间、冷却时间和保压压力等工艺参数的变化对塑件产品翘曲的影响趋势及其原因。结果表明:对所选参数,保压压力对塑件翘曲的影响最为显著,且保压压力取注射压力的95%左右可使产品的翘曲量达到较小的程度;产品翘曲量随料温升高,注射时间减短而减小;冷却时间对翘曲量的影响甚微;模具温度对翘曲影响较为复杂。根据分析结果,优化了塑件的成型工艺参数,使得翘曲量进一步减小。 相似文献
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You-Min Huang Hsiang-Yao Lan 《The International Journal of Advanced Manufacturing Technology》2006,30(3-4):233-246
Stereolithography (SL) is one of the rapid prototyping (RP) systems that use liquid photopolymer resin as the raw material for building prototypes. The photopolymer type of the RP system employs lasers to selectively expose the surface of the liquid resin. The absorbance of energy leads to photo-polymerization that transfers the liquid resin into solid. Subsequently, the phenomenon of volume shrinkage is unavoidable, and the curl distortion changes with the different laser scan paths, even affecting the geometric profile of the final-parts. The volume shrinkage and curl distortion are the major causes that lead to poor accuracy of the built prototype. In order to understand and improve the curl distortion and the geometric profile, so as to find a simple and suitable laser scan path. This paper first of all uses simulation and experiment to explore the deformation and shrinkage during the process of photo-polymerization while the liquid resin uses a laser beam to carry out single line scanning or single layer scanning in liquid free surface, and further understands the final change of geometric profile. Secondly, it investigates into the curl distortion and changes of geometric profile occurred in the three-dimensional part by different scan paths. Finally, a simple, proper, and effective laser scan path planning is suggested to decrease the curl distortion, and promote the dimension accuracy and the profile of the final-parts. Besides, this paper also mentions the feasibility of multi-optical processing. 相似文献
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L. Gopalakrishnan K. Srihari 《The International Journal of Advanced Manufacturing Technology》1999,15(8):587-596
The focus of this work was to develop a robust assembly process for low and high input/output (I/O) ball grid arrays (BGAs). The test vehicles considered had a wide variety of components including full and perimeter array BGAs, and ultrafine pitch peripheral leaded devices. Experimental design techniques were applied in order to identify, screen, and control the parameters that affect the stencil printing process. The factors that affect the process were screened using Tagu-chi-based methodology. These significant factors and their interactions were then further analysed using full factorial designs. The volume and the quality of the solder paste deposits were considered as the response variables. Response surface plots were developed to provide process windows for paste deposition. Process capability studies were performed to evaluate the capability of the solder paste deposition process. Boards were assembled using optimal settings obtained from the experiments. No process-induced defects were found, and 100% yield was obtained. 相似文献
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Palash Kumar Maji P. S. Banerjee A. Sinha 《The International Journal of Advanced Manufacturing Technology》2008,36(5-6):510-515
In today’s competitive world, the life-style of the average human being has become very fast. This causes a huge number traffic
accidents resulting in various types of injuries. In India, most of these accidents take place during bike riding and this
causes different types of fracture of bones. One of these injuries is head injury. For the proper treatment of such patients,
demands for patient-specific craniofacial bio-implants are increasing day by day. This kind of ‘tailored’ implant development
through near net shape manufacturing is a highly challenging task since the developmental time and cost has to be as low as
possible. At the Central Mechanical Engineering Research Institute (CMERI), one such process of implant development was explored
taking one case of head injury. The implant was developed through the “3D CAD-rapid prototyping (RP)-rapid tooling (RT)-investment
casting (IC)” route. For achieving the task, only the facilities available at CMERI were utilized. 相似文献
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A common issue in the design of measurement instruments is the comparison between different solutions in terms of components of the measurement chain, data processing or even measurement principles; the predicted instrumental uncertainty is the driving parameter for such a comparison. While in many situations the linearization of the measuring model allows using the standard ISO GUM procedure, in complex cases it might be necessary to proceed with Monte Carlo simulations as per ISO GUM supplement 1. This paper describes a method that combines the factorial design of experiments (DOE) and the ISO GUM supplement 1 uncertainty evaluation method to guide the instrument designer in the instrument configuration optimization. The proposed approach allows estimating, in the design phase, the overall instrumental uncertainty for different configurations, the instrument sensitivity to the accuracy in the measurements of its inputs and the effects on systematic and random measurement errors deriving from the choice of all instrumental variables. The use of data populations selected with the DOE criteria allows recovering valuable parameters equivalent to the sensitivity factors of the GUM linearized approach. The data analysis allows separating the critical factors that must be accurately controlled from those only weakly affecting the measurement uncertainty. The method has been applied to a case study where the metrological performances of a system devoted to the measurement of the acoustic radiation emitted by a vibrating panel in a reverberant enclosure had to be assessed. 相似文献
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Design of experiments approach to the study of tribological performance of Cu-concentrate-filled PPS composites 总被引:1,自引:0,他引:1
The tribological performance of copper-concentrate (CC) mineral deposit as the filler in polyphenylene sulfide (PPS) was studied as a function of the filler proportions and sliding test variables. CC is a complex mixture of CuS, FexOy, SiO2, Al2O3, and other trace materials. The design of experiments based upon L9 (34) orthogonal arrays by Taguchi was used. Sliding tests were performed in the pin-on-disk configuration against a hardened tool steel (55-60 HRC) disk. The improvement in wear resistance of PPS was considerable with the use of fillers. The lowest steady state wear rate of 0.0030 mm3/km was obtained for PPS+20%CC+15%PTFE composition. It was two orders of magnitude lower than that of unfilled PPS. The variations in steady state coefficient of friction with the changes in filler proportions and sliding test variables were small. The transfer film was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). X-ray photoelectron microscopy (XPS) was used to detect chemical reactive species developed during sliding, especially in the interface between transfer film and its counterface. Wear particles and the polymer worn surfaces were analyzed by energy dispersive spectroscopy (EDS) for elemental distribution. 相似文献