Michael Greulich, Matthias Greul and Theo Pintat
Rapid prototyping (RP) systems were designed to reduce the time taken to develop new products, and, today, available RP systems work with different techniques using paper…
Abstract
Rapid prototyping (RP) systems were designed to reduce the time taken to develop new products, and, today, available RP systems work with different techniques using paper, polymers and waxes. In order to fulfil the demand for the direct production of metallic prototypes for functional application and testing, the Fraunhofer Institute for Applied Materials Research (IFAM) has developed a new process, named “multiphase jet solidification (MJS)”, which is able to produce metallic or ceramic parts. The MJS process uses low‐melting alloys or a powder‐binder mixture which is squeezed out through a computer‐controlled nozzle. Parts are manufactured layer by layer and the “green parts” are debinded and sintered to reach final density. Presents experiences of using this new technique, along with some results.
Details
Keywords
Sunpreet Singh and Rupinder Singh
This paper aims to review the industrial and biomedical applications of state-of-the-art fused deposition modelling (FDM)-assisted investment casting (FDMAIC). Brief literature…
Abstract
Purpose
This paper aims to review the industrial and biomedical applications of state-of-the-art fused deposition modelling (FDM)-assisted investment casting (FDMAIC). Brief literature survey of methodologies, ideas, techniques and approaches used by various researchers is highlighted and use of hybrid feedstock filament-based pattern to produce metal matrix composite is duly discussed.
Design/methodology/approach
Pattern replica required for investment casting (IC) of biomedical implant, machine parts, dentistry and other industrial components can be directly produced by using FDM process is presented. Relevant studies and examples explaining the suitability of FDMAIC for various applications are also presented.
Findings
Researches to optimize the conventional IC with FDM solutions and develop new hybrid feedstock filament of FDM done by researchers worldwide are also discussed. The review highlights the benefit of FDMAIC to surgeons, engineers and manufacturing organizations.
Research limitations/implications
The research related to this survey is limited to the suitability and applicability of FDMAIC.
Originality/value
This review presents the information regarding potential IC application, which facilitates the society, engineers and manufacturing organizations by providing variety of components for assisting FDM. The information reported in this paper will serve doctors, researchers, organizations and academicians to explore the new options in the field of FDMAIC.
Details
Keywords
Mukesh K. Agarwala, Vikram R. Jamalabad, Noshir A. Langrana, Ahmad Safari, Philip J. Whalen and Stephen C. Danforth
Commercial solid freeform fabrication (SFF) systems, which have been developed for fabrication of wax and polymer parts for form and fit and secondary applications, such as moulds…
Abstract
Commercial solid freeform fabrication (SFF) systems, which have been developed for fabrication of wax and polymer parts for form and fit and secondary applications, such as moulds for casting, etc., require further improvements for use in direct processing of structural ceramic and metal parts. Defects, both surface as well as internal, are undesirable in SFF processed ceramic and metal parts for structural and functional applications. Process improvements are needed before any SFF technique can successfully be commercialized for structural ceramic and metal processing. Describes process improvements made in new SFF techniques, called fused deposition of ceramics (FDC) and metals (FDMet), for fabrication of structural and functional ceramic and metal parts. They are based on an existing SFF technique, fused deposition modelling (FDM) and use commercial FDM systems. The current state of SFF technology and commercial FDM systems results in parts with several surface and internal defects which, if not eliminated, severely limit the structural properties of ceramic and metal parts thus produced. Describes systematically, in detail, the nature of these defects and their origins. Discusses several novel strategies for elimination of most of these defects. Shows how some of these strategies have successfully been implemented to result in ceramic parts with structural properties comparable to those obtained in conventionally processed ceramics.
Details
Keywords
Nikolay K. Tolochko, Sergei E. Mozzharov, Igor A. Yadroitsev, Tahar Laoui, Ludo Froyen, Victor I. Titov and Michail B. Ignatiev
A comparison of selective laser sintering (SLS) and selective laser cladding (SLC) methods is presented. Loose single‐component, Ni‐alloy powder was used in this study. The powder…
Abstract
A comparison of selective laser sintering (SLS) and selective laser cladding (SLC) methods is presented. Loose single‐component, Ni‐alloy powder was used in this study. The powder feeding system formed the flow of powder particles directed into the zone of laser spot. The particles were deposited directly onto a substrate or onto the top of a pedestal. The powders were treated with a CW‐ Nd:YAG laser (λ=1.06 μm). The beam was motionless relative to the powder bed. As a result, the samples of sintered or remelted powders were built up as the vertical rods. The geometrical characteristics, structure and mechanical properties of samples were investigated.
Details
Keywords
P.M. Dickens, R. Stangroom, M. Greul, B. Holmer, K.K.B. Hon, R. Hovtun, R. Neumann, S. Noeken and D. Wimpenny
The Tooling and Casting subgroup of the European Action on Rapid Prototyping (EARP) has undertaken a project to investigate the problems associated with using rapid prototype…
Abstract
The Tooling and Casting subgroup of the European Action on Rapid Prototyping (EARP) has undertaken a project to investigate the problems associated with using rapid prototype models as sacrificial patterns for investment casting. The accuracy and surface finish of the models and the castings were also assessed so that a comparison could be made. Models from each process were manufactured by different members of EARP and then three foundries were each given a set of models to convert to castings. Observes that one of the oldest metal manufacturing techniques, which dates back to 4000‐6000 BC, is being used with one of the most modern ‐ rapid prototyping.
Details
Keywords
Munish Chhabra and Rupinder Singh
This paper seeks to review the industrial applications of state‐of‐the‐art additive manufacturing (AM) techniques in metal casting technology. An extensive survey of concepts…
Abstract
Purpose
This paper seeks to review the industrial applications of state‐of‐the‐art additive manufacturing (AM) techniques in metal casting technology. An extensive survey of concepts, techniques, approaches and suitability of various commercialised rapid casting (RC) solutions with traditional casting methods is presented.
Design/methodology/approach
The tooling required for producing metal casting such as fabrication of patterns, cores and moulds with RC directly by using different approaches are presented and evaluated. Relevant case studies and examples explaining the suitability and problems of using RC solutions by various manufacturers and researchers are also presented.
Findings
Latest research to optimize the current RC solutions, and new inventions in processing techniques and materials in RC performed by researchers worldwide are also discussed. The discussion regarding the benefits of RC solutions to foundrymen, and challenges to produce accurate and cost‐effective RC amongst AM manufacturers concludes this paper.
Research limitations/implications
The research related to this survey is limited to the applicability of RC solutions to sand casting and investment casting processes. There is practically no implication in industrial application of RC technology.
Originality/value
This review presents the information regarding potential AM application – RC, which facilitates the fabrication of patterns, cores and moulds directly using the computer‐aided design data. The information available in this paper serves the purpose of researchers and academicians to explore the new options in the field of RC and especially users, manufacturers and service industries to produce casting in relatively much shorter time and at low cost and even to cast complex design components which otherwise was impossible by using traditional casting processes and CNC technology.
Details
Keywords
Mukesh Agarwala, David Bourell, Joseph Beaman, Harris Marcus and Joel Barlow
Considers efforts to date to produce parts by direct selective laser sintering (SLS) of metals, including post processing to improve structural integrity and/or to induce a…
Abstract
Considers efforts to date to produce parts by direct selective laser sintering (SLS) of metals, including post processing to improve structural integrity and/or to induce a transformation. Provides a brief overview of the basic principles of SLS machine operation, and discusses materials issues affecting direct SLS of metals and the resultant properties and microstructures of the parts. Reviews results of past efforts on SLS of metal systems such as Cu‐Sn, Cu‐Solder (Pb‐Sn), Ni‐Sn, pre‐alloyed bronze (Cu‐Sn). Finally discusses more recent efforts on SLS of bronze‐nickel powder mixtures in greater detail.
Details
Keywords
Haihua Wu, Dichen Li and Nannan Guo
The purpose of this paper is to develop a novel process of integral ceramic molds for investment casting of hollow turbine blades.
Abstract
Purpose
The purpose of this paper is to develop a novel process of integral ceramic molds for investment casting of hollow turbine blades.
Design/methodology/approach
At first, a resin pattern of a hollow turbine blade prototype is fabricated by stereolithography (SL). And then aqueous gelcasting process is utilized to fill the resin pattern with ceramic slurry of low viscosity and low shrinkage, through in situ polymerization of the slurry a ceramic mold is formed. At last, the ceramic mold for investment casting of hollow turbine blade is obtained by vacuum drying, pyrolyzing and sintering.
Findings
An integral ceramic mold is successfully fabricated by combining SL and gelcasting process, cores and shell are connected with each other and thus high relative position accuracy is guaranteed. Properties of integral ceramic mold at room temperature and high temperature satisfy the requirements of directional casting for complex‐shaped thin‐walled blades.
Research limitations/implications
Because the integral ceramic mold is a close body, it is very difficult to directly measure its inner dimensions and the relative position accuracy of cores and shell, and the further research is needed.
Originality/value
This method enhanced the versatility of using SL prototype in the fabrication of integral ceramic mold for investment castings. Although this paper took a hollow turbine blade as an example, this method is also capable of fabricating integral ceramic molds for other complex investment castings.
Details
Keywords
Kamaljit Singh Boparai, Rupinder Singh and Harwinder Singh
The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition…
Abstract
Purpose
The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications.
Design/methodology/approach
The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated.
Findings
It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts.
Research limitations/implications
Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications.
Practical implications
Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry.
Originality/value
This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.
Details
Keywords
Neal K. Vail, Badrinarayan Balasubramanian, Joel W. Barlow and Harris L. Marcus
Reports that measurable amounts of polymer degradation occur during the fabrication of objects from polymer coated ceramic powders by selective laser sintering (SLS). Argues that…
Abstract
Reports that measurable amounts of polymer degradation occur during the fabrication of objects from polymer coated ceramic powders by selective laser sintering (SLS). Argues that because the binder is important in achieving strong green parts that can be handled with minimal breakage during post‐processing operations, it is essential to minimize the extent of binder losses. As the first step towards understanding the mechanisms of binder degradation, this paper presents a thermal model of the physical system, noting that the agreement between theory and experiment are good. The model is used to help determine the most influential parameters affecting binder losses during fabrication from polymer coated powders. Predicts that adjustments to laser beam diameter, laser scanning distance and gaseous environment will strongly affect polymer binder degradation during processing. Further predicts correctly that polymer degradation during SLS processing is not sensitive to the inherent degradation kinetics of the polymer.