Laminated Object Manufacturing Research Articles

Laminated-Object-Manufacturing*/Laminated object manufacturing - A method for the production of topological optimization parts

Topologisch optimierte Bauteile gestatten maximale Steifigkeit bei minimalem Materialeinsatz. Für die Erzeugung solcher Topologien werden meist Algorithmen eingesetzt, die Fertigungseinschränkungen auf Kosten von optimalen Ergebnissen berücksichtigen und keine variablen Materialdichten zulassen. Dieser Fachartikel stellt ein additives Herstellungsverfahren zur Fertigung global optimaler Topologien vor. Als Ergebnis können mittels der ausgewählten Algorithmen Bauteile mit höherer Steifigkeit hergestellt werden.   The optimal topology of components leads to maximum stiffness with minimum material use. To generate these topologies, normally algorithms are employed that tackle manufacturing limitations at the cost of the optimum. This article introduces an additive manufacturing method to enable the production of global topology optimization results. The findings show that by implementing the selected algorithm the stiffness of the components are higher than what could have been produced by conventional techniques.

Effect of Laser Power on Component Strength in Laser Sintering

Prototyping or model making is one of the important steps to finalize a product design. It helps in conceptualization of a design. Before the start of full production a prototype is usually fabricated and tested. RP processes namely Stereo-lithography (SL), Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM) and Laminated Object Manufacturing (LOM) are described. In Selective Laser Sintering (SLS) process, fine polymeric powder like polystyrene, polycarbonate or polyamide etc. (20 to 100 micrometer diameter) is spread on the substrate using a roller. Before starting CO2 laser scanning for sintering of a slice the temperature of the entire bed is raised just below its melting point by infrared heating in order to minimize thermal distortion (curling) and facilitate fusion to the previous layer. The laser is modulated in such a way that only those grains, which are in direct contact with the beam, are affected. Once laser scanning cures a slice, bed is lowered and powder feed chamber is raised so that a covering of powder can be spread evenly over the build area by counter rotating roller. In this process support structures are not required as the un-sintered powder remains at the places of support structure. It is cleaned away and can be recycled once the model is complete. This research has examined the effect of Laser power as well as processing parameters on the mechanical properties of selective laser sintered parts from DURAFORM PA In this research tensile specimens of Polyamide (DURAFORM PA) material as per the test standard ‘ASTM D638’ are fabricated. This test method covers the determination of the tensile properties of unreinforced and reinforced plastics in the form of standard dumbbell-shaped test specimens when tested under defined conditions of pre-treatment, temperature, humidity, and testing machine speed. The effects of varying the Laser power, generated by the laser, on the physical and mechanical properties of produced specimens. The energy density is varied by changing the laser power at a fixed value of laser scan spacing. Knowing the relationship between SLS parameter settings and material properties will make it possible to manufacture parts with predetermined properties, customized for various applications.

Rapid prototyping by heat diffusion of metal foil and related mechanical testing

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.

3D 프린팅 방식의 적층방향에 따른 시제품의 기계적 특성 비교에 관한 연구

Article history: This paper summarizes the results of an investigation into the environmental factors that have an indirect impact on parts quality, as well as those process variables and modeling information that have a direct impact. The effects of strength, surface hardness, roughness, and accuracy of shape, that is, qualities that users generally need to know, were evaluated with laminating direction experimentally. The 3D printing methods used in this experiment were fused deposition modeling (FDM), stereolithography apparatus (SLA), selective laser sintering (SLS), 3D printing (3DP) and laminated object manufacturing (LOM). The goal was to achieve a high standard of quality control and product quality by optimizing the fabrication process.

Laminated fabrication of 3D queue micro-electrode and its application in micro-EDM

3D micro-electrode used in micro electrical discharge machining (micro-EDM) is difficult to be fabricated. Based on laminated object manufacturing (LOM) process, this paper superimposed multilayer 2D micro-structures together to fit out 3D micro-electrode and applied it in micro-EDM to process 3D micro-cavity mold. Firstly, 100-μm-thick Cu foils were cut by wire-electrical discharge machining (WEDM) to obtain multilayer 2D micro-structures, and then these 2D micro-structures were connected together to fit out 3D micro-electrode through vacuum pressure thermal diffusion welding. Secondly, under the effect of 80-V voltage, 0.2-MHz pulse frequency, 800-ns pulse width, and 4200-ns pulse interval, the 3D micro-electrode was applied in micro-EDM and 3D micro-cavity mold with high surface quality was obtained. Thirdly, in order to reduce the adverse impact of electrode wear on machining precision of 3D micro-cavity mold, 3D queue micro-electrode was used to process the same 3D micro-cavity mold, in which the first electrode is for rough machining and the others for fine machining. Finally, based on the above studies, two kinds of 3D queue micro-electrodes were fabricated, and the 3D micro-cavity molds with surface roughness Ra = 0.48 μm were obtained through micro-EDM. Compared with the scanning 3D micro-EDM process, the 3D micro-cavity mold can be obtained through up and down reciprocating method of the 3D queue micro-electrode, featuring simple machining process and high efficiency.

Laminated fabrication of 3D micro-electrode based on WEDM and thermal diffusion welding

3D micro-electrode which is used in micro-electrical discharge machining (micro-EDM) is difficult to be fabricated. This paper proposes a method of micro-double-staged laminated object manufacturing (micro-DLOM) to fabricate 3D micro-electrode, and verifies its feasibility through the fabrication of 3D micro-electrode. Firstly, under machining parameters of 10μs pulse width, 40μs pulse interval, 0.42A wire cutting current and 80V voltage, 100μm-thick Cu foils were cut to obtain multi-layer 2D micro-structures. Then, under the process parameters of 850°C thermal diffusion temperature, 10h thermal diffusion time and 100N forces, multi-layer 2D micro-structures were connected together by vacuum pressure thermal diffusion welding to fit the 3D micro-electrode. Finally, based on the above-mentioned studies, three kinds of 3D micro-electrodes were fabricated by micro-DLOM process and the 3D micro-electrodes were applied in micro-EDM to process 3D micro-structures. Compared with the scanning 3D micro-EDM process, 3D micro-electrode only requires up and down reciprocating method to process 3D micro-structure, which has high processing efficiency.

Laminated fabrication of micro-stepped gear mold based on WEDM and thermal diffusion welding

This paper presents a method of micro-double-staged laminated object manufacturing (micro-DLOM) for fabricating three-dimensional (3D) micro-molds and verifies its feasibility of fabricating of micro-stepped gear molds. First, under the action of 10 μs pulse width, 40 μs pulse interval, 0.28 A wire-cutting current, and 60 V discharge voltage, a 100-μm-thick Cu foil is cut by wire electrical discharge machining (WEDM) to obtain a multilayer two-dimensional (2D) microstructure. Under the technological parameters of 850 °C thermal diffusion temperature, 10 h thermal diffusion time, and 1.0 N/mm2 pressure, the multilayer Cu 2D microstructure is then connected by vacuum-pressure thermal diffusion welding to fit the gear molds with two- and three-stage steps. Finally, on the basis of ultrasonic powder molding, two- and three-stage step plastic gears are respectively obtained. Compared with the ultraviolet lithography (UV-LIGA) process, the new process can fabricate complicated 3D microstructure with free-form surfaces; compared with the femtosecond laser-layering flat-scanning ablation process, the new process cuts only 2D microstructure of each layer with high processing efficiency; and compared with the micro-electrical discharge machining (EDM) process, the new process omits the step of microelectrode fabrication. Moreover, because there is no loss in the course of the microelectrode process, micro-molds in which the depth-to-width ratio is beyond limitation can be fabricated.

Feasibility of preparing of silicon nitride ceramics components by aqueous tape casting in combination with laminated object manufacturing

Abstract Homogeneous green silicon nitride sheets consisting of 48.7 vol.% ceramic particles were prepared by tape casting. The slurry, used to prepared green tapes, own obvious shear-thinning behavior. No noticeable precipitation during tape casting process was found revealed by the result of energy dispersion spectrum analysis. Components with complex shapes were fabricated by stacking layer by layer of the green sheets and a subsequent pressureless sintering at 1800 °C for 1 h. All α-Si 3 N 4 has transformed into β-Si 3 N 4 indicated by the result of X-ray diffraction. Due to the high homogeneous packing of the ceramic particles in the green bodies, the ceramic components could be sintered to full density with no noticeable distortions. Good flexural strength for the ceramic samples was observed.

The Progress and Application of Rapid Prototying Technology

The principle and application of rapid prototyping technology were presented. Several typical rapid prototyping technology were introduced, such as the Stereo Lithography Appearance, Laminated object manufacturing, fused deposition modeling, selective laser sintering, three dimensional spray adhesive technology. The rapid prototyping technology was used in manufacturing, clinical surgical, defense technology, ceramics, dental, and so on. The choke point of rapid prototyping technology application was analyzed, such as molding materials, precision error, and the performance of data sharing software. The future development trend of rapid prototyping technology is prospected also.

Slurry-based additive manufacturing of ceramic parts by selective laser burn-out

Abstract This study proposes a novel process of slurry-based additive manufacturing of ceramic parts by selective laser burn-out (SLB). The process employs the slurry layer to replace the sheet material used in the process of laminated object manufacturing (LOM) and computer-aided manufacturing of laminated engineering materials (CAM-LEM). A part of binder and solution in the fresh slurry layer permeated into the dried green layers to achieve a good binding strength; then the green part was build with laser irradiation to burn out binder. Two scanning modes were used; the outline scanning traced out the outline of the predefined part slice geometry, and cutting scanning facilitated removal of excess material. Consequently, the new process benefits the fabrication of the large parts as LOM and CAM-LEM possessing. Many accessory facilities used in LOM and CAM-LEM are not required. The feasibility of the new process is verified through the fabrication of the alumina parts.

Ultrasonically driven molten resin bulge for the formation of metal micro-structures in laminated die cavity

This paper proposes the use of ultrasonic bulge-forming process to fabricate T2 copper foil micro-structures. This approach involves the ultrasonic plasticization of powder in a laminated die cavity and the subsequent formation of a molten resin bulge. The laminated die is fabricated by micro-double-staged laminated object manufacturing and is then used as a concave micro-cavity. This technique uses ultrasonic melt polymer powder as a soft punch. Then, T2 copper foils are extruded into the concave die cavity. Consequently, the replication of the micro-bulging parts to the concave micro-cavity is achieved. This study also determined the appropriate parameters for ultrasonic bulge-forming process. Finally, the micro-two-stage gear, micro-three-stage gear and micro-cone bulge-forming parts were manufactured with good quality. The proposed technology can be applied to effectively reproduce the fine complex structure of concave micro-cavities. In contrast to traditional techniques, this method avoids issues arising from the incorrect location of the concave–convex die.

Image-based adaptive crosshatch toolpath generation for laminated object manufacturing

The adaptive crosshatching concept has been introduced for better waste material removal process in Laminated Object Manufacturing. However, the existing approaches that involve a STereoLithography model require additional information from other sources for determining adaptive crosshatch patterns, and for determining the toolpath from intersection points between these customised patterns and cross-sectional contours on their associated layers. Visual representation, on the other hand, seems to be more logical in practice for generating an adaptive crosshatch toolpath. Therefore, the image processing technique has been applied in this research for ease of adaptive crosshatch toolpath generation. For this approach, a uniform crosshatch pattern is created first as a common platform for the entire model. The pattern is modified next for each layer before being mapped onto the layer to determine the toolpath. An algorithm has been developed, and successfully implemented in the LabVIEW program. Some examples are illustrated in this paper to demonstrate the proposed approach.

Application of Rapid Prototyping Technology on Development of Medical Equipment

The prototype of a production can be manufactured directly from its 3D CAD model data by using rapid prototyping technology, and can be renewed conveniently after modifying the CAD model. In this paper, the basic principle, typical prototyping systems are introduced, and rapid prototyping methods such as selected laser sintering of powder material, fused deposition modeling of threadlike material and laminated object manufacturing are presented. An application of rapid prototyping technology on design and development of first aid kit is described in detail. It is indicated that rapid prototyping technology is an effective means to lower the cost and shorten the period of development of medical equipment.

Optimally orient and position multiple solid objects for batch production in 3D printing

3D printing or layered manufacturing is a computer-aided manufacturing process that fabricates parts through layer-wise deposition of material(s). Even though its material deposition techniques exploit wide spectrum of process physics including fused model deposition, stereolithography, selective laser sintering, laminated object manufacturing and inkjet print, its process planning are largely universal: similar workflow steps (e.g., build tray stacking, slicing, tool-path/dot-map generation) and similar objectives (e.g., fast build time, high accuracy, reduced material consumption). The configurations of the print step encapsulate the heterogeneity of the process physics and the associative assistive procedures (e.g., compensation, support).This paper describes our ongoing research into developing an optimization solution to assist process planning to meet the multiple, oftentimes competing objectives. In particular, this paper focuses on batching multiple objects for simultaneous production within the same build tray. Even though throughout this paper we use Fused Deposition Modeling (FDM, [1]) as example to illustrate 3D printing production, our solution is printing technology agnostic and generally applicable to other printing technologies.

Technique Achievement of Glass Objects Using Kiln Casting Method

In the context of the competitive actual environment, the production need to adapt to the preferences of the consumers, this represents the essential goal for all manufacturers. The production flexibility can be achieved by designing and marketing of new products or/and modify existing products in short time and at low cost. The technique presented in these article addresses of manufacturers and designers who made glass products unique or small series, adapted to consumer demands. In recent decades, digital fabrication methods are developed in various fields (aeronautics, shipbuilding, automotive, construction, architecture, industrial design and so on) and gained great popularity due to relevant advantages over the traditional production methods. Sculptural surfaces (also called free form surfaces) of the product with aestethetic requirements and/or functional role can be achieved through various technologies RP & M (Rapid Prototyping and Manufacturing). The Rapid Prototyping technologies can be grouped unto two major categories. First one refers to additive processes RP. From this point of view there are over 40 different types such as: stereo lithography (SL), Laminated Object Manufacturing (LOM), Selective Laser Sintering (SLS), 3D Printing (3DP), Solid Ground Curring (GSC) and Fused Deposition Modelling (FDM). The second one consists of subtractive Rapid Prototyping. Subtractive Rapid Prototyping (SRP) is one of the methods used for processing digital models into physical objects used for RP and for Rapid Tooling (RT). It is difficult to say what method is the best RP/RT; every one of them has advantages and disadvantages. The choice of the appropriate method depends on many factors, such as: product geometry, material type, dimensional accuracy, surface roughness on finished product, and so on. The starting point of this work consists in three photographs that are digitally processed to achieve the expansion of 2D in 3D structure. The expanded model is imported into computer-aided manufacturing (CAM) software. The parameters required to processing on Computer Numerical Control (CNC) machine are set, in order to obtain the shape of the casting mold. The schedule of heat treatment for glass is adapted according to the characterics of glass, mold material and the type of kiln. Rheological behaviour of glass has a key parameter in processing glass. The steps of kiln casting process (temperature ramps, heat treatment time) are choose at some values of viscosity (also called viscosity points ) related with glass type and size of object. The presented method can be successfully used in the manufacturing process offering to companies the possibility of increasing the capacity of new product development.

A Variable-Impedance Prosthetic Socket for a Transtibial Amputee Designed from Magnetic Resonance Imaging Data

ABSTRACTThis article evaluates the design of a variable impedance prosthetic (VIPr) socket for a transtibial amputee using computer-aided design and manufacturing (CAD/CAM) processes. Compliant features are seamlessly integrated into a three-dimensional printed socket to achieve lower interface peak

Research on micro-electric resistance slip welding of copper electrode during the fabrication of 3D metal micro-mold

3D micro-mold fabricated by the micro double-staged laminated object manufacturing process (micro-DLOM) is formed via stacking and fitting of multi-layer 2D micro-structures. The connection of 2D micro-structures is related to forming accuracy and mechanical properties of 3D micro-mold. In this research, micro-electric resistance slip welding of copper electrodes was proposed to connect multi-layer 2D micro-structures. Firstly, the proper process parameters of slip welding were obtained through the welding experiment, and the temperature field of micro-electric resistance slip welding under such process parameters was simulated. Secondly, deposition effect of the copper bar electrode produced during slip welding was studied and the study results show that the copper element deposited in the slip welding area decreases as the surface roughness of copper electrode decreases. Finally, based on the above research, a square micro-cavity mold with micro-channel, a circular micro-cavity mold with cross keyway and micro gear cavity mold with two-stage steps were welded by the micro-electric resistance slip welding.

Rapid Laminated Manufacturing for Metallic Parts Based on Resistance Welding Double-Station LOM

The adhesive strength between the metallic sheets and the way to remove the waste are the key problems of the laminated object manufacturing (LOM) for metallic functional parts. To solve these problems, a novel resistance welding double-station LOM was presented in this paper with its basic principles and implementation approach introduced. With 302 stainless steel sheets of 0.1mm in thickness as the model material, the rapid laminated manufacturing for metallic parts was conducted. As a result the plastic rapid injection mold shows its diffusion welding effect between sheets up to complete combination and its strength is more than 600MPa. The surface of plastic product injected according to the mold reaches the standard in dimensional accuracy and surface finish. The experiment has proved that the resistance welding double-station LOM is an effective method of the direct rapid manufacturing for metal parts of high strength.

Rapid prototyping: een veelbelovende methode

Rapid prototyping is a method which makes it possible to produce a three-dimensional model based on two-dimensional imaging. Various rapid prototyping methods are available for modelling, such as stereolithography, selective laser sintering, direct laser metal sintering, two-photon polymerization, laminated object manufacturing, three-dimensional printing, three-dimensional plotting, polyjet inkjet technology,fused deposition modelling, vacuum casting and milling. The various methods currently being used in the biomedical sector differ in production, materials and properties of the three-dimensional model which is produced. Rapid prototyping is mainly usedforpreoperative planning, simulation, education, and research into and development of bioengineering possibilities.

Selecting Digital Deposition Methods to Meet 2D and 3D Application Requirements

The paper outlines methods for effectively selecting digital deposition technologies for 2D printing and 3D deposition when there are dozens of technologies from which to choose. We present a matrix of parameters for comparing and evaluating the costeffectiveness, performance capabilities and characteristics of currently available digital print and deposition technologies against the performance requirements of applications. The paper specifically cites 2D and 3D applications including folding carton production and plastic parts manufacturing requirements. The matrix structure provides researchers and technology developers with a flexible tool for fine-tuning the print and deposition technology selection process. This paper also examines how developers can use the matrix for integrating digital deposition technology into complex manufacturing assembly processes. Due to the space limitations that this publication affords, we provide the matrix in outline form with a few examples. Our research group has compiled a comprehensive matrix.The digitally controlled deposition methods covered in this presentation include: the various forms of inkjet, inkjet-like methods, Inkjet Liquid Binding Powder (IJLBP), syringe deposit / Robo-casting (RC), aerosol deposit, pump dispensing, Electron Beam Freeform Fabrication (EB3F), Shape Deposition Manufacturing (SDM), and Fused Deposition Modeling (FDM)/Fused Filament Fabrication (FFF). We have focused for this presentation on methods where a digitally controlled process deposits material on a substrate or a particulate build material. In this report we do not cover spread-coating methods using radiation curing, such as laser electro-photography, stereolithography (SLA), selective laser sintering (SLS), Selective Laser Melting (SLM), Electron Beam Melting (EBM), and Solid Ground Curing (SGC). Nor do we cover laminating build methods, such as Laminated Object Manufacturing (LOM). Our group covers these other technologies in an upcoming report. The matrix structures of all these reports will facilitate comparison of print, deposition and build methods against application requirements.We focus on the characteristics of the deposition methods that address application requirements. These encompass both the way the deposition method performs and what it can deposit. Performance factors include the rate at which it can deposit amounts of specific materials, the accuracy and consistency of deposition placement, deposition resolution, the pH and deposit material device tolerances, material viscosity ranges necessary for deposition, system temperature controls and tolerances, operating, deposition material velocity, grey-scale capabilities, and device performance life. Users would also need capital and operation costs in selecting deposition systems. Operating costs will, however, vary greatly depending upon particular use. We therefore have not included operating costs in the current presentation matrix. Deposited material characteristics include viscosity, surface tension, and method to dry, solidify, polymerize, cure or fix. Performance requirements for deposited films and builds include abrasion and chemical resistance, tensile strength, and market acceptance of output appearance.