共查询到20条相似文献,搜索用时 31 毫秒
1.
《Measurement》2016
This study focuses on formulation of robust design for vapour smoothing, an advanced surface finishing technique for finishing ABS replicas where hot vapours tend to level the uneven surface asperities. The process parameters of combined Fused Deposition Modeling (FDM) and Vapour smoothing (VS) process are optimized for sustainability of ABS replicas for biomedical applications. Six input parameters have been investigated, two of FDM and four of VS processes while surface roughness and hardness of ABS part is taken as response. The vapour smoothing process ensue ultra smooth finish with negligible deterioration of upper surface deducing maximum contribution of smoothing time (51.07%) and number of cycles (40.08%) on surface roughness. Hardness of replica has been slightly increased by maximum impact of orientation angle (34.69%) and postcooling time (44.46%) of ABS replicas which endorsed the use of FDM replicas for investment casting of biomedical implants. 相似文献
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Chil-Chyuan Kuo Ci-Ming Chen Song-Xuan Chang 《The International Journal of Advanced Manufacturing Technology》2017,91(5-8):1473-1479
Fused deposition modeling (FDM) is a process of fabricating three-dimensional physical models by layered manufacturing. However, the surface quality of acrylonitrile butadiene styrene (ABS) built with FDM technologies is not acceptable and is not satisfactory for most general engineering purposes. In this study, a polishing system was demonstrated to enhance surface finish of ABS parts fabricated by FDM. Polishing mechanism for ABS parts was investigated. The features of this system include high polishing efficiency, no waste chemicals, ease of operation, with excellent dimensional accuracy, and low equipment costs. Improving surface roughness of ABS parts by the use of acetone vapor not only has required dimensional accuracy but also has high process stability. A great reduction in average surface roughness for ABS parts about 98% was obtained. The polishing mechanisms for ABS parts fabricated by additive manufacturing were investigated in this study. 相似文献
4.
《Measurement》2016
Fused deposition modeling (FDM) is one of the widely used additive manufacturing technologies because it has flexibility and ability to build complex parts. The accuracy of parts fabricated by FDM is greatly influenced by various process parameters. FDM process has a complex mechanism in building parts and often poses difficulty in understanding adequately how conflicting FDM parameters will determine part quality and accuracy. Sectors such as medical implant, telecommunication, electronics and aerospace require increasingly higher levels of dimensional accuracy. Thus, traditional methods of ensuring quality do not effectively address global markets and customer’s needs. This study proposes an I-optimality criterion for the optimization of FDM process parameters in order to address the limitations of the commonly used traditional designs. This study also aims to develop mathematical models in order to establish nonlinear relationship between process parameters and dimensional accuracy. The results show that I-optimality criterion is very promising technique in FDM process parameter optimization. Confirmation experiments show that the proposed method has great advantages in the aspect of both accuracy and efficiency compared with traditional methods proposed in previous studies. 相似文献
5.
In this study, a topological design sensitivity of the air bearing surface (ABS) is suggested by using an adjoint variable
method. The discrete form of the generalized lubrication equation based on a control volume formulation is used as a compatible
condition. A residual function of the slider is considered as an equality constraint function, which represents the slider
in equilibrium. The slider thickness parameters at all grid cells are chosen as design variables since they are the topological
parameters determining the ABS shape. Then, a complicated adjoint variable equation is formulated to directly handle the highly
nonlinear and asymmetric coefficient matrix and vector in the discrete system equation of air-lubricated slider bearings.
An alternating direction implicit (ADI) scheme is utilized for the numerical calculation. This is an efficient iterative solver
to solve large-scale problem in special band storage. Then, a computer program is developed and applied to a slider model
of a sophisticated shape. The simulation results of design sensitivity analysis (DSA) are directly compared with those of
FDM at the randomly selected grid cells to show the effectiveness of the proposed approach. The overall distribution of DSA
results are reported, clearly showing the region on the ABS where special attention should be given during the manufacturing
process. 相似文献
6.
A. Boschetto L. Bottini 《The International Journal of Advanced Manufacturing Technology》2014,73(5-8):913-928
Fused deposition modeling (FDM) is a common additive manufacturing (AM) technology able to fabricate physical prototypes directly from virtual model without geometrical complexity limitations. Initially used to create concept models to help product design stage, FDM developed as regard materials, accuracy, and the overall quality of the output improved, becoming suitable for end use. At present, it is employed in process chains to significantly shorten product development times and costs and to produce parts in small and medium batch. A critical drawback which inhibits its diffusion is the obtainable accuracy. Only few indications, relating the dimensional deviations, exist, and they are conflicting each other, not allowing a reliable prediction. In this paper, a geometrical model of the filament, dependent upon the deposition angle and layer thickness, has been developed in order to predict the obtainable part dimensions. The model has been validated by an experimental campaign. The specimens have been investigated by means of profilometer analysis in order to study macrogeometrical and microgeometrical aspects. Finally, a case study highlighted the reliability of the model. The direct implication of this work is the capability, in process planning, to know in advance if the FDM part dimensions will satisfy the specification and the component will fit with others. Moreover, this model can be employed to choose the suitable manufacturing strategy in order to comply with industrial constrains and scopes. 相似文献
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Lütfi Taner Tunç Omer Mehmet Ozkirimli Erhan Budak 《The International Journal of Advanced Manufacturing Technology》2016,84(5-8):1483-1495
Fused deposition modeling (FDM) is one of the most popular additive manufacturing technologies for fabricating prototypes with complex geometry and different materials. However, current commercial FDM machines have the limitations in process reliability and product quality. In order to overcome these limitations and increase the levels of machine intelligence and automation, machine conditions need to be monitored more closely as in closed-loop control systems. In this study, a new method for in situ monitoring of FDM machine conditions is proposed, where acoustic emission (AE) technique is applied. The proposed method allows for the identification of both normal and abnormal states of the machine conditions. The time-domain features of AE hits are used as the indicators. Support vector machines with the radial basis function kernel are applied for state identification. Experimental results show that this new method can potentially serve as a non-intrusive diagnostic and prognostic tool for FDM machine maintenance and process control. 相似文献
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WANG Tianming XI Juntong JIN Ye School of Mechanical Engineering Shanghai Jiaotong University Shanghai China 《机械工程学报(英文版)》2007,20(1):100-106
To aim at prototype parts fabricated with fused deposition modeling (FDM) process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping (RP) process, the inherent characteristics of FDM process, and some micro-scratches on the surface of the extruded fiber. Based on the micro-characters of section shape of the FDM prototype, a physical model reflecting the outer shape characters is abstracted. With the physical simplified and deduced, the evaluating equations of surface roughness are acquired. According to the FDM sample parts with special design for experimental measurement, the real surface roughness values of different inclined planes are obtained. And the measuring values of surface roughness are compared with the calculation values. Furthermore, the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied. With the references of analytic conclusions, the measuring values of the experimental part surface are revised, and the revised values nearly accord with the calculation values. Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts, some concrete measures are proposed to reduce the surface roughness of FDM parts, and the applying effects are better. 相似文献
11.
Farzad Rayegani Godfrey C. Onwubolu 《The International Journal of Advanced Manufacturing Technology》2014,72(1-4):509-519
This paper presents the research done to determine the functional relationship between process parameters and tensile strength for the fused deposition modelling (FDM) process using the group method for data modelling for prediction purposes. An initial test was carried out to determine whether part orientation and raster angle variations affect the tensile strength. It was found that both process parameters affect tensile strength response. Further experimentations were carried out in which the process parameters considered were part orientation, raster angle, raster width and air gap. The process parameters and the experimental results were submitted to the group method of data handling (GMDH), resulting in predicted output, in which the predicted output values were found to correlate very closely with the measured values. Using differential evolution (DE), optimal process parameters have been found to achieve good strength simultaneously for the response. The mathematical model of the response of the tensile strength with respect to the process parameters comprising part orientation, raster angle, raster width and air gap has been developed based on GMDH, and it has been found that the functionality of the additive manufacturing part produced is improved by optimizing the process parameters. The results obtained are very promising, and hence, the approach presented in this paper has practical application for the design and manufacture of parts using additive manufacturing technologies. 相似文献
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针对熔融堆积成型工艺中的加工时间、尺寸精度、翘曲变形3个指标,选择线宽补偿(A)、挤出速度(B)、填充速度(C)和层厚(D)4个工艺参数作为控制因子。首先,通过正交实验确定控制因子对单个指标的影响程度,然后进一步利用灰关联度分析确定控制因子对综合指标的影响程度及最佳工艺参数组合方案。结果表明对综合工艺指标影响的主次顺序为A、D、C、B,最佳制作参数组合为A1B3C3D3。 相似文献
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G. Thimm G.A. Britton 《The International Journal of Advanced Manufacturing Technology》2002,19(6):448-453
This paper presents a new matrix method for calculating working dimensions and offsets for tolerance charts. The method is
part of a more general datum hierarchy tree technique for tolerance planning and control. The matrix method is suitable for
both manual and computer-aided computation. It has been implemented in an industrial program, CATCH, and a prototype artificial
intelligence (AI) program for process planning. The method has been successfully taught to engineering students in New Zealand
and Finland. Worked examples are provided to illustrate the method. The examples show how to calculate working dimensions
without offsets, and how to calculate an offset working dimension and an offset resultant dimension. 相似文献
15.
Yuh-Chyun Chiang Hsin-Chung Cheng Chiung-Fang Huang Jeou-Long Lee Yi Lin Yung-Kang Shen 《The International Journal of Advanced Manufacturing Technology》2011,55(5-8):517-526
This study investigates warpage of electronic dictionary battery covers fabricated using thin-wall injection molding as a replacement for conventional insert molding. The primary concern is the molding window in thin-wall injection molding for acrylonitrile?Cbutadiene styrene (ABS) and polycarbonate (PC)+ABS plastics. Finally, the process parameters for thin-wall injection molding that eliminate warpage of electronic dictionary battery covers are identified. Experimental results demonstrate that the area of the molding window for ABS exceeds that for PC+ABS. Analysis of the molding window reveals that ABS is more appropriate than PC+ABS for battery covers. Low melt temperature, high injection speed, and high packing pressure eliminate battery cover warpage. Melt temperature is the most important process parameter for eliminating warpage when using both ABS and PC+ABS. 相似文献
16.
The tendencies of cylinder surface topography changes during “zero-wear” process are mentioned.It is proved that the assessment of amplitude parameter of worn cylinder surface is sufficient to monitor the shape of the amplitude distribution (material ratio curve). The information that the standard deviation height of fine part resulted from wear process is proportional to maximum height of worn surface is very important. It is possible to obtain simulated worn surface profiles when the horizontal parameters of their fine parts are known. The presented above technique can be extended into worn cylinder surfaces measured in three dimensions.The last part of paper is devoted to prediction of the local cylinder linear wear, determined as change of amplitude parameter. This procedure is based on the linear dependence between volumetric wear and initial material volume of the cylinder surface topography. The new models were successfully used for a large number of cylinder liners after ‘zero-wear’ process in internal combustion engines. 相似文献
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A. Noriega D. Blanco B. J. Alvarez A. Garcia 《The International Journal of Advanced Manufacturing Technology》2013,69(9-12):2301-2313
Fused deposition modelling (FDM) is the most extended additive manufacturing technique up to date. In FDM, a thermoplastic material is extruded through a nozzle to form layers, and the final geometry is the result of consecutive superimposed layers. However, it is difficult to obtain an adequate dimensional accuracy for some applications due to the characteristics of the process. This paper proposes a method for increasing accuracy of the distance between parallel faces on FDM manufactured prismatic parts, consisting in replacing the theoretical values of CAD model dimensions by new optimized values. For this purpose, a model has been developed for predicting the dimensions of the manufactured parts, based on design characteristics. Particularly, this work has used an artificial neural network combined with an optimization algorithm, to determine the optimal dimensional values for the CAD model. Subsequently, CAD model is redesigned according to the dimensions provided by the optimization algorithm, and the part is manufactured. The results show that the application of this methodology allows for a reduction in manufacturing error of approximately 50 % for external dimensions and 30 % for internal dimensions. 相似文献
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Ko-Ta Chiang Fu-Ping Chang 《The International Journal of Advanced Manufacturing Technology》2007,35(5-6):468-479
This paper presents a systematic methodology to analyze the shrinkage and warpage in an injection-molded part with a thin
shell feature during the injection molding process. The systematic experimental design based on the response surface methodology
(RSM) is applied to identify the effects of machining parameters on the performance of shrinkage and warpage. The experiment
plan adopts the centered central composite design (CCD). The quadratic model of RSM associated sequential approximation optimization
(SAO) method is used to find the optimum value of machining parameters. One real case study in the injection molding process
of polycarbonate/acrylonitrile butadiene styrene (PC/ABS) cell phone shell has been performed to verify the proposed optimum
procedure. The mold temperature (M
T), packing time (P
t), packing pressure (P
P) and cooling time (C
t) in the packing stage are considered as machining parameters. The results of analysis of variance (ANOVA) and conducting
confirmation experiments demonstrate that the quadratic models of the shrinkage and warpage are fairly well fitted with the
experimental values. The individual influences of all machining parameters on the shrinkage and warpage have been analyzed
and predicted by the obtained mathematical models. For the manufacture of PC/ABS cell phone shell, the values of shrinkage
and warpage present the reduction of 37.8 and 53.9%, respectively, using this optimal procedure. 相似文献
19.
Anhua Peng Xingming Xiao Rui Yue 《The International Journal of Advanced Manufacturing Technology》2014,73(1-4):87-100
Fused deposition modeling (FDM) is gaining distinct advantages because of its ability to fabricate the 3D physical prototypes without the restrictions of geometric complexities, while when it comes to accuracy and efficiency, the advantages of FDM is not distinct, and so how to improve them is worthy of study. Focusing on process parameter optimization, such parameters as line width compensation, extrusion velocity, filling velocity, and layer thickness are selected as control factors, input variables, and dimensional error, warp deformation, and built time are selected as output responses, evaluation indexes. Experiment design is assigned according to uniform experiment design, and then the three output responses are converted with fuzzy inference system to a single comprehensive response. The relation between the comprehensive response and the four input variables is derived with second-order response surface methodology, the correctness of which is further validated with artificial neural network. Fitness function is created using penalty function and is solved with genetic algorithm toolbox in Matlab software. With confirmation test, the results are obtained preferring to the results of the experiment 1 with the best comprehensive response among the 17 experiment runs, which confirms that the proposed approach in this study can effectively improve accuracy and efficiency in the FDM process. 相似文献
20.
Abdulrahman Al-Ahmari Mohammad Ashfaq Abdullah Alfaify Basem Abdo Abdulrahman Alomar Abdelnaser Dawud 《Journal of Mechanical Science and Technology》2016,30(1):345-352
Electron beam melting (EBM) has been found to be a promising technology for producing complex shaped parts from gamma titanium aluminide alloys (γ-TiAl). The parts produced by this process are projected to have dimensions very close to the desired final shapes. However, the surface roughness of the parts produced by EBM is excessively rough. In many applications, it is necessary to improve the quality of manufactured parts using a convenient post process. This paper determines process parameters of end milling when it is used as a post process for the parts produced by EBM. Design of experiments has been used to study the effect of the selected input parameters of end milling (spindle speed, feed rate, depth of cut and coolant type) on the surface roughness of γ-TiAl parts. Response surface methodology is used to develop a predictive model for surface roughness. Effects of the selected milling process are investigated. This paper also optimizes the selected process parameters to minimize the value of the obtained surface roughness. 相似文献