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RAPID prototyping, JEWELRY industry, PARAMETRIC modeling, 3-D printers, CASE studies, and STEREOLITHOGRAPHY

The new research and technologies that have ensured the digitalization of industries and the introduction of smart manufacturing are still characterized by poorly studied processes. In particular, communication and integration between different platforms, which form the ecosystem of smart manufacturing, are subject to various communication problems. The research conducted and propounded in this article is based on the implementation of an integrated manufacturing system that involves parametric modeling, optimization, and additive manufacturing. The ecosystem analyzed guarantees communication between IT platforms such as Rhino-Grasshopper, for parametric modeling, and PreForm, slicing software for Formlab's stereolithographic 3D printers. For this purpose, C# scripts have been implemented in order to solve optimization problems in 3D modeling of objects and to guarantee integration between the two platforms. The latter script is configured as a real add-in for Rhino whose advantages are easily demonstrated thanks to the large number of recursive operations that are automated. [ABSTRACT FROM AUTHOR]

RAPID prototyping, INVESTMENT casting, ELECTRIC metal-cutting, MANUFACTURING processes, ELECTRODES, FEASIBILITY studies, MACHINING, and FABRICATION (Manufacturing)

This study fabricates a roughing electrode of electrical discharge machining (EDM) using a rapid prototyping (RP) system and investment casting technology, which reduces the overall time that is required for fabrication and the cost of the manufacturing process for a selected electrode. Pro/E (3D CAD) software is used to design the electrode prototype, which has a complex appearance, and to transform the CAD model into stereolithography (STL) format. An RP machine (Zcorp 402 3DP) is used to construct a gypsum-based powder model. After a sealing process using the permeation of resin, the water resistance and strength of the gypsum-based material are increased. The manufacturing process then involves creating a wax model with a gypsum electrode that is strengthened by resin permeation by casting a vulcanized silicone molding. The brass electrode is fabricated using investment casting technology. The results of an EDM test show that the brass electrodes with RP that are manufactured perform well and the total time that is required to machine the EDM electrode using RP is 15.8% less than the time that is required for a CNC machining process. [ABSTRACT FROM AUTHOR]

DRAWING (Metalwork), SHEET metal, MASS production, METALWORK, RAPID prototyping, and SHEET metal work

Due to the change from mass production to mass personalized production and the resulting intrinsic product flexibility, the automotive industry, among others, is looking for cost-efficient and resource-saving production methods to combining global just-in-time production. In addition to geometric manufacturing flexibility, additive manufacturing offers a resource-saving application for rapid prototyping and small series in predevelopment. In this study, the FDM process is utilized to manufacture the tooling to draw a small series of sheet metal parts in combination with the rubber pad forming process. Therefore, a variety of common AM polymer materials (PETG, PLA, and ABS) is compared in compression tests, from which PLA is selected to be applied as sheet metal forming die. For the rubber pad forming process, relevant processing parameters, i.e., press force and rubber cushion hardness, are studied with respect to forming depth. The product batch is examined by optical evaluation using a metrological system. The scans of the tool and sheet metal parts confirm the mechanical integrity of the additively manufactured die from polymer and thus the suitability of this approach for small series in sheet metal drawing processes, e.g., for automotive applications. [ABSTRACT FROM AUTHOR]

CLOUD computing, THREE-dimensional printing, RAPID prototyping, MANUFACTURING processes, and RESEARCH & development

At present, some service platforms for 3D manufacturing encounter problems, including the low level of integration with digital design ability, the single character of cooperative printings, the uneven distribution of 3D printing resources, and the high 3D design requirements of users. To overcome these issues, a cloud service platform for the seamless integration of digital design and rapid prototyping manufacturing was established using ASP.NET, WebGL, WebSocket, and SQL Server in combination with C# language and JavaScript. The goals were to realize a design and rapid prototyping of mechanical equipment parts that are browser based and provide online digital design services, such as the parametric design of key parts, downloading of models, format conversion, and virtual assembly. The client application layer, server processing layer, database layer, and working machine end application layer of this cloud 3D printing platform were set up. The result of the design module could be printed remotely in 3D. Practical application showed that the platform could effectively improve the R&D and design speed of the parts and components of the mechanical equipment and reduce the effort of designers. In particular, this platform would be suitable for users without a 3D design background. The design and rapid prototyping parts of the platform satisfied the dimensional precision required by enterprises, which provides an important basis for the further verification of the design correctness for small- and medium-sized enterprises and has high application value. [ABSTRACT FROM AUTHOR]

RAPID prototyping, METAL extrusion, METALWORK, METALWORKING machinery, and METAL industry

A rapid prototyping and high-precision technology for manufacturing a linear motion (LM) guideway is proposed in this paper. In this technology, a trough is laid on the die, and a ram is used to press the billet before extrusion to produce high hydrostatic stress on the cutting edge of the die. The punch diameter is designed to be larger than the die hole but smaller than the die diameter. Hence, the action of the punch traveling downward to extrude the billet can increase the hydrostatic pressure around the cutting edge of the punch and die, thereby eliminating product fracture. LM rails of linear guides were formed using an experimental test, in which all the product processes were completed in only a few minutes. The results indicated that this approach can extrude a part of the linear guide with an excellent burnished surface. The test range for the roughness of the burnished surface was R = 0.03-0.21 μm, and the tolerance band for the width and thickness ranged from IT1 to IT4. This novel approach provides a more rapid prototyping technology as well as precise sizes higher than those obtained using traditional manufacturing methods. [ABSTRACT FROM AUTHOR]

GLOBAL optimization, RAPID prototyping, ENGINEERING design, INJECTION molding, MANUFACTURING processes, GENETIC algorithms, and CHEMICAL molding

Injection molding (IM) is a versatile manufacturing process capable of rapid prototyping and mass-producing high-quality polymer parts. The present study mainly investigates the challenge of designing multiple molding gates on the complex arbitrary part surface in 3D. Currently, this problem is a challenge in mold design and engineering experience still plays an important role in designing the molding gates. To reduce the human intervention in the design process, the present study proposed a novel methodology with the following major steps: 1) using Poisson disk sampling (PDS) to preselect candidate gate locations automatically within the suitable gating region specified by designers; 2) using a space-filling initialization strategy and efficient global optimization to find the optimal gate locations. In the present setting, the molding gate design problem is formalized as a discrete optimization problem. The PDS is employed to construct the discrete solution space and EGO is used to efficiently search through a large solution space for the best design. To further promote optimization efficiency, a parallel implementation of EGO is also proposed. The effectiveness of the proposed methods is validated in two design cases. The results demonstrate the proposed EGO and Parallel EGO method is superior that the Genetic Algorithm (GA) and Surrogate Optimization (SO). Moreover, the proposed Parallel EGO converges faster than all other alternatives. [ABSTRACT FROM AUTHOR]

RAPID prototyping, METAL foils, MECHANICAL engineering, MECHANICAL behavior of materials, and APPROXIMATION theory

Rapid prototyping has made massive strides in the technological industries and is at the fore front of innovation. However, the majority of these methods use different types of plastic and other materials including resins and flour, for the production of prototypes. They can only be used as visual prototypes in most instances and do not provide sufficient information for direct material testing which is needed to understand the mechanical properties for large-scale production. The current methods employing powder metals have their limitations and are very expensive. There is an emphasis on the production of metal parts because they provide an environment for testing rather than approximations and usually give more insight into the design parameters. This research presents a new rapid prototyping process for the production of high-quality metal parts that can be used after production with minimal post-processing. The process is a combination of laminated object manufacturing and soldering techniques. The process is referred to as composite metal foil manufacturing, and its effectiveness is validated with lap-shear testing, peel testing, microstructural analysis and comparative studies. Specimens were produced using copper foils of 100-μm thickness. The results obtained have been promising demonstrating that the process is not only capable of producing metal parts efficiently but can also produce stronger parts compared to traditional methods. This shows that the proposed process has the capability to be a strong candidate in the field of metal prototyping. [ABSTRACT FROM AUTHOR]

RAPID tooling, RAPID prototyping, NICKEL-plating, INJECTION molding of plastics, EPOXY resins, and ALLOY plating

A rapid tooling approach is presented in this article to build an injection mould for low-volume production of plastic parts. This is an indirect tooling method using a rapid prototype model as a casting pattern. A layer of nickel-phosphorous alloy is plated on the casting pattern before it is cast in the aluminium-filled epoxy resin to form a cavity insert. After the removal of the casting pattern, the nickel-phosphorous alloy layer left on the wall of epoxy cavity insert acts as a protective layer to improve the tool life. The insert is installed in a mouldbase for injection moulding experiment. Three plastic parts are tried on the moulds built by this rapid tooling approach. This research has shown that manufacturing an indirect rapid tooling using electroless nickel plating for low-volume production of plastic injection mouldings is feasible for the rapid prototyping models. The cavity insert can be fabricated using commonly available low-cost materials within 48 h. More importantly, the tool life is longer under normal plastic processing conditions and quality mouldings are obtained. [ABSTRACT FROM AUTHOR]

FOCUSED ion beams, OPTICAL glass, MATERIALS science, RAPID prototyping, SEMICONDUCTOR materials, and OPTICAL fibers

Focused ion beam (FIB) milling is widely used in fields such as the semiconductor industry and materials science research. The direct writing and small feature size also make FIB milling attractive for rapid prototyping of novel photonic structures. In this manuscript, we describe in detail a FIB milling procedure which enables high-resolution fabrication of complex micro- and nanostructures with precise geometry control. Two different procedures (for 2D and 3D structures) are described and implemented on the tip of a glass optical fiber for fabricating diverse structures embedded on or below the tip surface. The procedures described here can be easily adjusted and implemented on any conductive or non-conductive substrate. [ABSTRACT FROM AUTHOR]

HIGH strength steel, CLAMPS (Engineering), and SHEET metal

Flexible Roll Forming (FRF) allows the forming of components with a variable cross section along the length of the component. However, the process has only limited application in the automotive industry due to wrinkling in the flange which currently prevents the forming of high strength steels and limits the part shape complexity. This paper presents a new forming technology, Incremental Shape Rolling (ISR), where a pre-cut blank is clamped between two dies, and then a single forming roll is used to incrementally form the material to the desired shape. The new process is similar to some Incremental Sheet Forming (ISF) approaches but with the difference that Incremental Shape Rolling (ISR) allows the manufacture of longitudinal components from high strength metal sheets. In this work, a numerical model of the ISR of a straight section is developed. Experimental prototyping trials are performed and are used to validate the numerical model which is then applied to analyse the new forming process. The results show that in ISR, tensile residual strains are developed in the flange. Flange wrinkling is observed and directly linked to the number of forming passes that are used in the process. [ABSTRACT FROM AUTHOR]

FUNCTIONALLY gradient materials, FINITE element method, MATHEMATICAL optimization, FOAM, PHENOMENOLOGICAL biology, and STRUCTURAL optimization

Weight reduction is one of the main concerns when designing any component as it reduces material cost and green house gas emissions, among other aspects. Several numerical approaches exist in the literature with the objective of having any component with known mechanical loading become optimized in terms of mass minimization and stiffness maximization. Thus, the objective of this work is the development of optimized structures maintaining the same geometry by means of cellular materials, namely the gyroid infill, and generating functionally graded cellular structures with higher stiffness-to-weight ratio. Remodelling algorithms based on biological phenomena, namely bone growth, as well as Bi-evolutionary structural optimization (BESO) were employed to obtain the density map allowing the material functional gradient distribution. Smoothing functions were tested as a possibility of enhancing stiffness as abrupt density changes are avoided. The gyroid infill was characterized in order to create a phenomenological law based on bone remodelling laws. The gyroid law was implemented on the analysis FEMAS (opens-source, academic and educational FEM and meshless method software) software which presented the density map as an output. Each gradient consisted on areas at a similar density being concatenated into one solid. The different solids, at different density levels, are assembled thus creating the material functional gradient. Lastly, simulations consisted on three distinct and benchmark flexural load cases. Specimens were printed using FFF technology in PLA (E = 3145 MPa, ν = 0.3) having then been tested experimentally according to the appropriate load case. Numerical results correlated with the experimental results in terms of accuracy between theoretical and experimental stiffness where there was a greater accuracy for the specimens subject to a Four-Point bending load case, where only a 16% gap was verified between numerical and experimental flexural stiffness. [ABSTRACT FROM AUTHOR]

RAPID prototyping, SLICING machines (Cooking), ALGORITHMS, ERROR analysis in mathematics, FABRICATION (Manufacturing), and REGRESSION analysis

Rapid prototyping fabricates physical prototypes from three-dimensional designing models using the additive process with layers. Aims at reducing the inevitable volumetric error induced in phrase of model slicing which impacts the shape accuracy of fabricated entity, a fast determining scheme of optimal slicing orientation for least volumetric error is proposed. The work analyses the staircase effect between two consecutive layers, then infers a direct computing formula of volume deviation of a whole model. Introduces the term of area weighted normal to express the significant effect of facet area on volumetric error and converts the optimal orientation determining problem to the least absolute deviation linear regression issue. Employs prominent components analysis on weighted normal set to obtain an approximate orientation efficiently, then optimizes the solution through few searchings in neighboring orientation space. The validity and efficiency of the algorithm are evaluated on several examples. Results demonstrate that proposed algorithm consumes less than 32 % of computation load and adaptively obtains the optimal slicing orientation. [ABSTRACT FROM AUTHOR]

GEOMETRIC modeling, RAPID prototyping, MANUFACTURING processes, GEARING machinery, LOGARITHMIC functions, CUTTING (Materials), and PRODUCTION (Economic theory)

The geometric analysis of a face-gear hob is introduced in this article. We examined the logarithmic spiral and the Archimedean spiral backward-turned curves in profile distortion aspect. The cutting edge of the hob defines the face-gear dentation, which is why the equations of the cutting edge have to be known for manufacturing. We worked out the mathematical analysis of the backward-turned curves, the cutting edge, the face surface, and the relief side surface of the hob in general case. Based on these, we designed a conical hob, working out its three-dimensional virtual CAD model. Using rapid prototyping technique, we produced the real physical model of this hob, and the hob was actually manufactured. We carried out three-coordination measuring analysis of the rapid prototyping model and the actually manufactured model. We analyzed the measured results and presented the evaluation of our results. [ABSTRACT FROM AUTHOR]

FUSED deposition modeling, RAPID prototyping, EXTRUSION process, RAPID tooling, MANUFACTURING processes, and FINITE element method

Additive manufacturing has evolved from a rapid prototyping tool to a set of manufacturing processes for functional parts. One of their most outstanding features is the ability to build complex geometry parts. However, their industrial application is limited because these parts exhibit heterogeneous and porous micro/mesostructures with anisotropic behavior. These structural characteristics, mainly porosity, are strongly related to the building parameters. In this work, a computational multiscale homogenization approach was implemented to determine the mechanical properties of unidirectional and criss-cross mesostructures generated by a material extrusion process (MEP). Representative volume elements (RVE) for simplified and real-like pore geometries were created to model the mesostructures and to perform the multiscale analysis. Stiffness tensor for each RVE was obtained and graphically represented to observe the mechanical properties as a function of the orientation. A great influence of the pore geometry on mechanical properties was observed. Finally, by comparing with experimental data, the results obtained were validated. [ABSTRACT FROM AUTHOR]

NUMERICAL control of machine tools, RAPID prototyping, CONTINUITY, GEOMETRIC modeling, THREE-dimensional modeling, MACHINING, and METAL cutting

Efficient and productive manufacturing of freeform shapes requires a suitable three-dimensional CAD model at the entrance to the CAM system. The paper deals with the impact of NURBS or B-spline CAD model geometric continuity on the accuracy and productivity of 5-axis ball-end milling of freeform surfaces. The relationship between a different order of CAD model geometric continuity and the quality of the toolpath generated in CAM system is analysed and demonstrated on an example of a Blisk blade profile. In order to reveal the effect of CAD geometry on the quality of the machined surface, linear interpolation of cutter location points, i.e. piecewise linear discrete toolpath, is considered. Also, no further smoothing of the toolpath is applied. The distance of the cutter location points is commonly used as the indicator of toolpath quality. In addition, the discrete curvature of a linear discrete toolpath is introduced here, and its dependence on the curvature and continuity of the underlying CAD model is demonstrated. In this paper, it is shown that increasing the order of CAD model geometric continuity significantly eliminates sharp changes in the distance of cutter location points, and smoothes the discrete curvature of the toolpath. Finally, it is experimentally verified that increasing the continuity of the CAD model from G0 to G3, while maintaining the same cutting conditions, leads to an increase in workpiece accuracy and a reduction in machining time, without the need to smooth the toolpath generated in the CAM system. [ABSTRACT FROM AUTHOR]

RAPID prototyping, LASERS, PROTOTYPES, MANUFACTURING processes, and DEFORMATIONS (Mechanics)

“Step effect” is one of the major concerns for engineers because it affects the surface quality in layer manufacturing. Instead of constant thickness, adaptive slicing procedures use slices of variable thickness that are governed by the model geometry, manufacturing process, material, and rapid prototyping system. The RP system has the capability of fabricating the layer between a minimum and maximum thickness with certain intermediate thickness during the model making and is indispensable. Due to agglomeration of powder and upward deformation of the layer, the layer’s thickness in powder-based rapid prototyping processes is restricted. To improve surface quality, the current study constructs a paving system to minimize the layer thickness. Based on a wet process-ceramic laser rapid prototyping technique, a paving system, which can fabricate ultra-thin layers to a thickness of 20 μm and can achieve instant layer drying, was successfully constructed. A strategy of compensative layer was induced to improve accuracy of the Z-axis. Due to the ultra-thin layers, a plane surface finishing of Rz = 15∼24 μm was obtained. [ABSTRACT FROM AUTHOR]

MANUFACTURING processes, RAPID prototyping, ALGORITHMS, PRODUCTION engineering, and INDUSTRIAL engineering

The hollowing process plays an important role in some rapid prototyping technologies such as stereo lithography apparatus (SLA), fused deposition modelling (FDM) and select laser sintering (SLS). This paper introduces an efficient two-dimensional hollowing algorithm. The principles of algorithm and implementation are presented. In addition, a detailed analysis is used to study the effect of the scanning path and online character in the actual fabricating process. [ABSTRACT FROM AUTHOR]

RAPID prototyping, PROTOTYPES, RAPID tooling, MANUFACTURING processes, FLEXIBLE manufacturing systems, and SURFACE roughness

As the race to launch a product successfully into the market increases in speed, the drive to reduce metal tooling lead time will become more important. Time reduction for fabricating metal tools depends on fast, efficient, and flexible manufacturing processes that dramatically reduce lead times while not sacrificing mechanical properties. A novel process of rapid tooling, non-baking of ceramic moulding, was studied. It uses a casting mould made from ceramic slurry and rapid prototyping to form a metal tool. It provides a quick, accurate, and relatively cost-effective route for producing metal parts or tools. The process and key technologies are analysed in detail. The process has been used in the automotive, consumer products, casting, and toy industries. Applications show that the total costs for new products can be reduced by as much as 40–60%, and lead times can be reduced by 50–60%. The surface roughness is approximately Ra = 3.2, and it can be improved to better that Ra = 1.6 by polishing. The dimensional accuracy relative to size is about ±0.1 mm for dimensions less than 200 mm. [ABSTRACT FROM AUTHOR]

RAPID prototyping, FUNCTIONALLY gradient materials, MANUFACTURING industries, BIOMEDICAL materials, ALGORITHMS, MATHEMATICAL models, and PERFORMANCE evaluation

In this paper, research on developing adaptive rapid prototyping/manufacturing (RP/M) algorithms for functionally graded material (FGM)-based biomedical models is reported. Non-uniform rational B-spline and FGM-based features have been proposed to present the models. Innovative algorithms for tool path optimization in RP/M have been developed, including: (1) a mixed tool path algorithm to generate contour/offset tool paths to represent varying material composition along the boundary of each sliced layer of a model and zigzag tool paths to present the internal area of a single material to simplify computing and processing and (2) adaptive algorithms to control the RP/M nozzle/print head to minimize the build time of each sliced layer according to the geometrical characteristics of the model. Case studies of FGM-based biomedical models have been used to verify and demonstrate the performance of the research in terms of algorithm effectiveness. [ABSTRACT FROM AUTHOR]

POROUS materials, RAPID prototyping, PROTOTYPES, TISSUE engineering, and MANUFACTURING processes

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. [ABSTRACT FROM AUTHOR]