1,720,959 research outputs found
Filling balance optimization by best gate location
No full textThe quality of an injection molded part is strongly influenced by the filling balance of the mould cavity. This paper presents a method and the relevant software application to determine the best gate location for an injection molded part. The proposed optimization method automatically and iteratively calculates the gate position that maximizes the melt flows balance during the filling phase. The software is based on the Moldflow Plastics Insight®/Microsoft Visual Basic® interface and uses a non-linear optimization algorithm based on the Gauss-Newton and Conjugated Gradient techniques. The effectiveness of the developed method is demonstrated through some significant case studies
Polymer Injection Forming (PIF) Of Thin-Walled Sheet Metal Parts - Preliminary Experimental Results
No full textPolymer Injection Forming (PIF) is a new technology to manufacture sheet metal/polymer macro-composite components in a one-operation production process. During the process, a metal blank is shaped inside an injection mould by using the injection pressure of the molten polymer. In the same step the polymer is permanently bonded to the metal sheet creating a fully finished product in only one production step. Thus, the PIF technology is a combination of the injection moulding and sheet metal forming processes. In this paper, the influence of the main injection moulding process parameters on the sheet metal formability has been experimentally investigated. The results show that melt temperature and clamp force have a great effect on the sheet deformation since they affect respectively the ductility of the sheet metal and the degree of pure drawing. In order to maximize sheet metal formability avoiding the flash formation, the main process parameters have been optimized
Switchover control in the polymer injection forming process
No full textPolymer Injection Forming (PIF) is a new technology to manufacture sheet metal/polymer macro-composite components in a one-operation production process. During the process, a metal blank is formed inside an injection mold by means of the pressure of the molten polymer. Changing from velocity control to pressure control just before the mold is filled is a common practice in the traditional injection molding process. In this paper, different switchover strategies for the PIF process were investigated. Shot to shot consistency obtained by these methods was evaluated by means of process variations in terms of cavity melt pressure
Fluid Structure Interaction Analysis in Manufacturing Metal/Polymer Macro-Composites
No full textPolymer Injection Forming (PIF) is a new manufacturing technology for sheet metal-polymer macro-composites, which results from the combination of injection moulding and sheet metal forming. This process consists on forming the sheet metal according to the boundary of the mould cavity by means of the injected polymer. After cooling, the polymer bonds permanently to the metal resulting in a sheet metal-polymer macro-composite product. Comparing this process to traditional ones (where the polymeric and metal parts are joined together after separate forming) the main advantages are both reduction of production costs and increase of part quality. This paper presents a multi-physics numerical simulation of the process performed in the Ansys/CFX environment
Economical break-even analysis between steel and aluminium moulds by early cost estimation
No full textThis paper provides a systematic and quantitative method for the analysis of the economical break-even between steel and aluminium moulds used in the injection moulding process. The proposed approach takes into account both mould manufacturing (material purchase and machining) and injection moulding costs (cycle time). Thermoplastic material cost is not considered since it does not change in a comparative analysis. The total costs are estimated against the part life volume and the break-even point between steel and aluminium technological solution is determined. The proposed method is validated through an industrial case study
Filling Balance Optimization for Plastics Injection Molding
No full textThe quality of an injection molded part is strongly influenced by the filling balance of the mold cavity. Gate location is the principal balance factor and it heavily depends on designer’s experience and knowledge. In this paper, a three-step method is proposed which aims at determining the gate location that maximizes the filling balance of a mold cavity. First numerical simulations of the filling process are run changing gate position opportunely. Then third order regression surface method is applied to determine the gate location which minimizes the filling times standard deviation of the mesh nodes located along the cavity boundaries. The proposed method can be used for single gated mold cavities or multiple gated ones where the gates are positioned symmetrically. The results obtained from an industrial case study highlighted the effectiveness of the proposed approach in finding the optimal gate location by a restricted number of simulations
Calibration of the Filling Simulation of an Injection Moulding Process by Artificial Neural Networks
No full textThe reliability of numerical simulation of the thermoplastics injection moulding process by means of finite elements and finite differences methods strongly depends on the accuracy of the parameters that describe the material from both a rheological and a thermal point of view. Simulations are often un-calibrated due to the scarcity and inaccuracy of available data. The main objective of the paper is to calibrate the filling phase of numerical simulation of an injection moulding process through the use of pressure transducers placed in the mould cavity. The software calibration was formulated as an inverse problem, considering the numerical code as a direct model. The inverse problem aims at finding a set of viscosity parameters which minimises an objective function representing, in the least square sense, the difference between experimental and numerical pressure data. In order to minimise this objective function a feed-forward back-propagation artificial neural network (ANN) approach was used. The melt pressure developments estimated by the simulation using calibrated-viscosity data was very close to the measured ones
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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