International Journal of Rapid Manufacturing (12 papers in press)
Additive Manufacturing of H13 Tooling Element with Conformal Cooling Channel Using MIG Cladding
by Fisseha Legesse, Sajan Kapil, Hari Vithasth, K.P. Karunakaran
Abstract: Hybrid Layered Manufacturing (HLM) is a synergic integration of additive and subtractive manufacturing processes. It takes the positive aspects of both the processes such as accuracy through subtractive and reduction of material through additive. In this work, The Metal Inert Gas (MIG) cladding has been used for addition and CNC milling machining is used for subtraction. The process parameters for MIG cladding of H-13 tool steel material was investigated using Taguchi DOE method. The effect of different process parameters such as current, torch speed and standoff distance, on weld bead width, height and penetration have been studied using ANOVA. This paper describes the methodology of analyzing and manufacturing of a die element using H13 tool steel material with a proper conformal cooling channel and in-situ preheating process using an induction heating system.
Keywords: Hybrid Layered Manufacturing; Baffle & Bubbler cooling; MIG Cladding; In-situ preheating.
Multi Objective Optimization of Fused Deposition Modelling process parameters using RSM and fuzzy logic for build time and support material
by Manu Srivastava
Abstract: Additive Manufacturing (AM) is around three-decade old technology and enables quick transition from concept to physical models in a matter of hours. Fused deposition modelling (FDM) is a promising and robust AM technique with proven ability to build prototypes of complex and intricate shapes using reasonable time and cost. Optimization of FDM process requires optimization of various qualitative and quantitative responses. This work presents multi-objective FDM optimization using RSM embedded fuzzy logic analysis. Six process parameters and two responses are considered for the current experimentation on Fortus 250mc modeller based on FDM technology.
Keywords: Additive manufacturing; Fused deposition modelling; Build time; Support material Volume; Response surface methodology; Fuzzy logic.
Digital Design Integrity for Additive Manufacturing: Examining reliability issues in the digital preproduction process
by Steven L. Brown, Harry A. Pierson
Abstract: Despite a literature base stretching over three decades, the digital pre-production process for additive manufacturing continues to lack integration and robustness. Current best practice relies on operators to identify potential issues to prevent scrap and rework. While most academic research focuses on systematic tessellation approximation errors, this paper offers a detailed investigation of nonsystematic translation errors and their root causes. All stages of the digital pre-production process (tessellation, slicing, and tool path generation) were found to be equally vulnerable, and no common commercial software tool was found to be superior in its ability to prevent translation errors. Given the improbability of completely eliminating digital translation problems under the current paradigm, this paper proposes an alternative with new feedback loops to ensure digital design integrity.
Keywords: additive manufacturing; 3D printing; additive manufacturing quality; meshing; slicing; toolpath generation; CAD; tessellation; translation verification.
Numerical and experimental analysis of product development by composite metal foil manufacturing
by Javaid Butt, Habtom Mebrahtu, Hassan Shirvani
Abstract: The paper presents a new additive manufacturing process for the production of high quality metal parts using metal foil and is termed as Composite Metal Foil Manufacturing. It is a blend of Laminated Object Manufacturing and soldering/brazing strategies. A calculated model of a machine in view of the new process has been outlined and its parts accepted for usefulness either by experimentation or recreations. The advantages of the process include simplicity and flexibility in operation combined with strong and high quality resulting metal parts. The product development has two stages -- the principles of Laminated Object Manufacturing for cutting and stacking of foils and brazing for joining. A 300W MIYACHI fibre laser is used for cutting of metal foils. The foils are coated with a special brazing paste, 80% zinc and 20% aluminium by weight, with the use of 710 applicator. The thickness is measured at every instance with two Microtrak 3 TGS on either side of the build platform. The cutting process produce heat that melts the brazing paste at the edges of the foils and allow them to stay in alignment. It makes moving the part onto the heating plates easy for final joining. The heated plates apply heat and pressure to ensure proper bonding of the foils. In this paper, the process is described as a whole with detailed explanation of every component and their functionality. Furthermore, some results of investigations on the sub-processes; laser cutting, final joining and transient thermal analysis are shown.
Keywords: additive manufacturing; laminated object manufacturing; metal parts; metal foil; laser cutting; brazing; CFD analysis.
The performance of tool shape on efficiency and quality of forming in incremental sheet-forming process
by Bhavin V. Desai, Keyur P. Desai, Harit K. Raval
Abstract: Incremental sheet-forming process is an economical alternative of conventional sheet metal forming process to manufacture parts in small or medium batch size as well as to produce sheet metal prototypes. In the present investigation, to study the effect of tool shape on efficiency and quality of the formed component, two different kinds of tools of same diameter with hemispherical end and spherical end are employed. Forming time is considered as a measure of process efficiency and profile accuracy as a quality of forming. The Taguchi experimental design is applied for experimentation. ANOVA is performed to know the level of significance of the process parameters. It is found that incremental depth step is the most significant process parameter affecting forming efficiency followed by forming speed (feed). Forming speed, wall angle and incremental depth step are the most significant parameters that affect the forming quality.
Keywords: ANOVA; incremental sheet forming; profile accuracy; Taguchi.
Producing parts with multiple layer thicknesses by projection stereolithography
by Pekka Lehtinen, Matti Kaivola, Harri Korhonen, Jukka Seppälä, Jouni Partanen
Abstract: We present a novel method to increase the manufacturing speed and versatility in lithography-based additive manufacturing processes. Usually, a part made with additive manufacturing consists of equally thick layers that are fabricated upon one another. We use a projection stereolithography (PSL) system to manufacture parts containing several layer thicknesses, which reduces the manufacturing time and adds controllability to the system. The method is based on the possibility to control the cure depth by adjusting the operation wavelength. To demonstrate the applicability of the PSL system for this purpose, we used two different operation wavelengths to produce parts that include 50- and 300-µm layers. The method presented in this paper can be used in several PSL techniques to increase their performance by offering a new tool to control the layer thickness without affecting the manufacturing resolution.
Keywords: 3D printing; additive manufacturing; AM; cure depth; layer thickness; multiple layers; penetration depth; photopolymers; projection stereolithography; PSL; SL; SLA; stereolithography.
Friction and wear rate characteristics of parts manufactured by fused deposition modelling process
by Pavan Kumar Gurrala, Srinivasa Prakash Regalla
Abstract: The present research work aims at understanding the effect of fused deposition modelling process parameters on tribological properties such as friction and wear rate. Two pin-on-disc parameters, namely normal load and sliding speed have been chosen. Orientation angle of the part is chosen as the third varying parameter. Test specimens are manufactured as per the design of experiments set-up. Response surfaces and interaction effects of process parameters are studied through response surface methodology. Analysis of variance results indicate that there is substantial interaction effect of build orientation angle on comparison with the other two parameters on the tribological properties. Scanning electron microscope micrographs of the worn surfaces reveal the importance of part build orientation and its contribution towards surface strength properties. The tribological studies conclude that cracks are formed in the specimens when tested at high load, high speed and low part build orientation angle of the part.
Keywords: ANOVA; design of experiments; friction; fused deposition modelling; pin-on-disc; response surface methodology; wear rate.
Project InnoDino: additively innovative dinosaur design and manufacturing
by Nicholas A. Russell, Jacob Floyd, Joseph Caston, Manuel R. Villalpando, Ismail Fidan
Abstract: Additive manufacturing (AM) is a quickly growing field and promises to be revolutionary to the manufacturing industry and to society. One novel application of AM is the ability to recreate history and make the past come alive to present-day audiences. One of the major challenges that must be overcome for AM technologies to become ubiquitous in society is the joining of 3D printed parts. For many applications, parts must be able to move relative to each other which require the use of joints. Another challenger is the limited capacity of most printer beds on the market today. To make large scale, functional parts, 3D printed pieces must be joined or fused to make large, continuous parts. Both of these challenges are explored within the context of recreating a struthiomimus dinosaur by completely 3D printing and assembling the dinosaur. This current paper reports the milestones in making a struthiomimus dinosaur.
Keywords: additive manufacturing; assembly; design; dinosaur; joint; reverse engineering.
Surface roughness improvement using volumetric error control through adaptive slicing
by Mohammad Taufik, Prashant K. Jain
Abstract: This research presents the development of advanced adaptive slicing procedure to improve the surface roughness by adaptively selecting the layer thickness based on the user specified volumetric error (VE) value bound. However, most of the researchers have developed slicing procedures to improve the part surface quality under cusp height concept. Moreover, cusp height-based adaptive slicing procedures do not have any direct control on VE. It is possible that with very little variation in cusp height the large variation in VE may occur on shallow surfaces. In contrast, the advanced adaptive slicing algorithm has been developed and implemented to vary layer thickness directly under a specified VE value on the fused deposition modelling (FDM) part surfaces although this procedure can also be useful for all AM processes to control VE. In this work, different models have been used to estimate VE and surface roughness according to the layer thickness changes.
Keywords: 3D printing; adaptive slicing; additive manufacturing (AM); computer-aided design (CAD); fused deposition modelling (FDM); modelling; 3D visualisation; slicing algorithm; surface roughness; volumetric error.
Special Issue on: Additive Manufacturing in Architecture
The Current State of Autography
by Kostas Grigoriadis
Abstract: As the practice of using notations to translate from two to three-dimensions is gradually being replaced by the direct, autographic relaying of building information digitally, the separation between designing and building is diminishing. Key to lessening further this division are heterogeneous materials, the imminent use of which can instigate the gradual superseding of building components and effectively tectonic construction. Pre-empting their anticipated widespread application, a main point syntax is presented of the expected changes that will occur in architecture as a result. Following this, a novel design method of using particle system elements to simulate the fusion of materials is deployed in the redesign of a building facade element through a multi-material. The ensuing focus is the fabrication of the element, which is performed by converting material data from the CFD program into a 3D-printable format. The current technical limitations of architectural autography are discussed through this workflow.
Keywords: autography; allography; architecture; digital design; multi-materials; functionally graded materials; particle system elements; cfd; rapid manufacturing; 3d printing; design theory.
In and Out of Control: Latent Opportunities within an Additive Manufacturing Process
by James Kerestes, Alayna Davidson
Abstract: Technology can become an active participant in the design process when users refrain from dictating how a tool should operate and perform. When digital and physical mediums are given participatory roles or authorship in the production of objects, the accepted conventions and typologies of design can be challenged and pushed beyond what is conceived to be possible and plausible. The research described in this article will explore the latent capabilities found within the equipment and materials utilized throughout the additive manufacturing process, and will examine their potential to incite form generation, material behaviour and fabrication. The focus will be on production methodologies that utilize material extrusion for the fabrication of physical objects. A series of production trials will explore and expand the origin of tectonic aesthetics relative to construction means and methods.
Keywords: Tool autopsy; computation; behavioral logic; idiosyncrasies; emergence; post-digital; robotics; additive manufacturing; material; machine latency.
Mesh Optimization for Spatial Wireframe Robotic 3D Printing
by Lei Yu, Dan Luo
Abstract: Most of the polygon meshing system and related algorithm are developed for geometrical optimization with rarely any practical consideration such as material performance and fabrication process. This paper intends to propose a different approach for mesh optimization that took practical elements such as material quality, fabrication sequence, and technical restriction into the consideration, developing a novel meshing algorithm. Through our novel nonlinear optimization process, a data intensive smart polygon mesh network system is generated that are optimized for a highly efficient construction process in coordination with a robotic FDM 3D printing system. The mesh network developed from such process and algorithm is structurally rational, cost efficient with far less construction time
Keywords: Mesh Optimization; FDM; Robotic Fabrication; 3D Printing Framework; Spatial Extrusion; Digital Computation; Digital Fabrication; Rapid Prototyping.