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DETERMINING THE INFLUENCE OF LAYER THICKNESS FOR RAPID PROTOTYPING WITH STEREOLITHOGRAPHY (SLA) PROCESS
Raju.B.S,,Chandrashekar.U,Drakshayani.D.N,Chockalingam.K
International Journal of Engineering Science and Technology , 2010,
Abstract: Stereolithography is a Rapid prototyping technique, which allows direct transformation of CAD files into epoxy resin parts for building the physical models, these are built from photo-curable thermosetting resins. Part quality in the Stereolithography process is a function of the build parameters such as hatch cure depth, layer thickness, orientation and hatch file. This paper attempts to identify and study the various process parameters governing thestereolithography system, specifically the influence of layer thickness related to the part characteristics. The part characteristics can be divided into part physical characteristics and mechanical characteristics. The part physical characteristics are surface finish, dimensional accuracy and distortion where as mechanical characteristics are flexural property, ultimate tensile strength and impact strength. Thus paper proposes to study the influence of the layer thickness (build parameters) over the part quality. The study is conducted on the test samples of SL 5530, which were built on SLA5000 machine, under different sets of process parameters and tested under ASTM specified test conditions. The results have been analyzed to achieve an optimal layer at which the mechanical properties are high with minimum dimensional instability, which is found to be 100 micron layer thickness. To obtain an optimallayer thickness for the SLA parts is the end result of the paper.
Dimensional accuracy of the skull models produced by rapid prototyping technology using stereolithography apparatus
A. Nizam,R.N. Gopal,L. Naing,A.B. Hakim
Archives of Orofacial Sciences , 2006,
Abstract: The purpose of this study was to determine the dimensional accuracy of the skull models produced by rapid prototyping technology using stereolithography apparatus. Computed tomography images were captured from four dry normal adult human skulls. The resultant 2-D images were stored in Digital Imaging and Communications in Medicine (DICOM) format. The segmentation of the images was prepared in MIMICS software. The slice files were then exported to a stereolithography apparatus (SLA) to produce the replica of each skull. Eight linear measurements were repeatedly made between identified landmarks on each of the original skull and its replica model using an electronic digital calliper. Each of the linear measurements was repeated 5 times and the average was taken to determine the absolute difference and percent difference between the original skull and its replica model. The overall absolute difference between the four human adult skulls and its replica models was 0.23 mm with a standard deviation of 1.37 mm. The percent difference was 0.08% with a standard deviation of 1.25%. The degree of error established by this system seems affordable in clinical applications when these models are used in the field of dental surgery for surgical treatment planning.
Rapid manufacturing and rapid tooling of polymer miniaturized parts using Stereolithography
Salmoria, Gean Vitor;Lafratta, Fernando H.;Biava, Matheus M.;Ahrens, Carlos Henrique;Ferreira, Pedro Z.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2008, DOI: 10.1590/S1678-58782008000100002
Abstract: currently, miniaturization is a major trend in the manufacturing and commercialization of new industrial products. when small-sized objects should be manufactured with dimensions of only a few millimeters or less, many difficulties can appear using traditional processes. an alternative to study these new requirements is through the use of rapid prototyping technologies. stereolithography (sl) has established itself as one of the most popular and reliable process allowing the rapid manufacturing of complex parts. this paper investigates the sl process, which directly produces small parts by rapid manufacturing, and also indirectly by rapid tooling. the processability of small parts was investigated using two different shapes. the pom and abs materials were used in the indirect manufacturing. the dimensional accuracy, precision and tolerance of micro parts were evaluated using metrological techniques. results showed accuracy and precision greater than 97% when small-parts are manufactured directly by stereolithography.
Aplication of the stereolithography technique in complex spine surgery
Paiva, Wellingson Silva;Amorim, Robson;Bezerra, Douglas Alexandre Fran?a;Masini, Marcos;
Arquivos de Neuro-Psiquiatria , 2007, DOI: 10.1590/S0004-282X2007000300015
Abstract: many techniques have been proposed for surgical training as a learning process for young surgeons or for the simulation of complex procedures. stereolithograpfy, a rapid prototyping technique, has been presented recently as an option for these purposes. we describe the case of a 12 years old boy, diagnosed with ewing′s sarcoma in the cervical spine. after a surgical simulation accomplished in the prototype, built by stereolithography, the patient was submitted to a c4 corpectomy and to a c4 and c3 laminectomy with anterior and posterior fixation, a non intercurrence procedure. this technique is an innovative and complementary tool in diagnosis and therapy. as a result, it is easier for the surgeon to understand the complexity of the case and plan the approach before any surgical procedure.
Rapid prototyping in Maxillofacial Surgery and Traumatology
Rosa, Everton Luis Santos da;Oleskovicz, César Fernando;Arag?o, Bruno Nogueira;
Brazilian Dental Journal , 2004, DOI: 10.1590/S0103-64402004000300015
Abstract: review of the literature from 1991 to 2002 on the use of rapid prototyping in the biomedical area emphasizes the applicability of this technique to aid diagnosis and planning in maxillofacial surgery and traumatology. a case report in which a tmj ankylosis relapse was treated using rapid prototyping (selective laser sintering) for surgery planning is presented. after one year, the patient's buccal opening was 45 mm. transitory paralysis of the facial nerve disappeared totally in six months.
The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts
Beal, V. E.;Ahrens, C. H.;Wendhausen, P. A.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2004, DOI: 10.1590/S1678-58782004000100007
Abstract: the utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. the use of this rapid tooling technique in powder metal injection molding is evaluated in this work. one of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. for example, steel molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. the discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. the optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. the dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).
The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts  [cached]
Beal V. E.,Ahrens C. H.,Wendhausen P. A.
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2004,
Abstract: The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. The discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. The optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. The dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. Moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).
Automated Tools for Rapid Prototyping
Pan,Jinping
计算机科学技术学报 , 1991,
Abstract: An automated environment is presented which aids the software engineers in developing data processing systems by using rapid prototyping techniques.The environment is being developed on VAX station.It can render good support to the specification of the requirements and the rapid creation of prototype.The goal,the methodology,the general structure of the environment and two sub-systems are discussed.
Critical Parameters Effecting the Rapid Prototyping Surface Finish
Journal of Mechanical Engineering and Automation , 2011, DOI: 10.5923/j.jmea.20110101.03
Abstract: A component can be manufactured in several ways. Rapid Prototyping technique is one among the material adding manufacturing process, building up its unique potential in the present scenario. This technique helps manufacture a product from the basic design of the component, thus optimizing the iterative product development process time and creating geometrically complex parts to precise dimensions. In the Rapid Prototyping process, surface finish is critical as it can affect the part accuracy, reduce the post-processing costs and improve the functionality of the parts. This paper presents an experimental design technique for determining the optimal surface finish of a part built by varying Build Orientation, Layer Thickness and keeping other parameters constant using the Fused Deposition Modeling (FDM) process. The design investigates the effect of these parameters on the surface finish. Experiments were conducted using a fractional factorial design with two levels for Layer Thickness and three levels for Build Orientation factor. The results are statistically analyzed to determine the significant factors and their interactions. The significant factors, their interactions and the optimum settings are proposed.
INTEGRATED USE OF RAPID PROTOTYPING AND METAL PLATING TECHNIQUES FOR DEVELOPMENT OF MICRO AIR VEHICLES
Dr. U. CHANDRASEKHAR,,Dr. K. VENKATESH,Dr. K. ELANGOVAN,,Dr. T. RANGASWAMY
International Journal of Engineering Science and Technology , 2011,
Abstract: This paper describes the synergistic application of rapid prototyping and metal plating technologies for development of micro air vehicles (MAV) with high strength-to-weight characteristic. Stereolithography and fused deposition techniques are employed to fabricate complex thermoplastic MAV prototypes with significant time-compression in production cycle. Electroless and electrolytic deposition processes are custom developed to deposit thin metallic foils of nickel and chromium over thermoplastic MAV prototypes. Plating plant with inherent provision for variation of process parameters is established and proof-of-concept studies are carried on plating of MAV prototypes. Experiments are conducted on metal plated thermoplastic test specimens for evaluating the mechanical behaviour and structural integrity properties. Present study is a conclusive demonstration of the use of layered manufacturing techniques in quick realisation of flight-worthy MAV systems.
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