The construction of machines consisting essentially of soft parts is a nascent and multidisciplinary research field between material science, machine engineering, and robotics. Soft silicones ...represent a promising class of materials for the creation of a vast multitude of biologically inspired entities. In the present work, a new type of mammalian vein‐inspired soft silicone pump is introduced and characterized, which is fabricated by virtual lost‐wax casting of 3D‐printed injection molds. These pumps can be actuated pneumatically or by internal gas combustion and preserve their functionality even after a freezing/unfreezing cycle. The possibility of using medical examination methods such as ultrasonic imaging to directly access flow information inside soft pumps is shown. Based on soda lime glass microspheres, a method is demonstrated to enhance contrast properties during such color online Doppler imaging for a detailed understanding of the inner fluid‐structure interactions.
There is a nascent research field on machines that are made essentially from soft materials. A new type of mammalian vein‐inspired soft silicone liquid pump is presented and characterized, that is based on lost‐wax casting of 3D printed injection molds. By functionalizing the material with contrast agents, inner workings can be visualized in real‐time by the use of medical ultrasonography.
To meet current demands, it is vital to blend new production technology with traditional ways. Additive manufacturing, often known as 3-Dimensional printing, is a rapidly expanding technology that ...has been widely adopted by various industries, and the foundry industry is one of them. Additive manufacturing (AM) is essential to the industry's fourth industrial revolution, which intends to bring about progressive improvements in business transactions by establishing a smart production system. Industry 4.0 has arrived in new markets that are focused on delighting customers by adding value to products and services. With its ability to produce parts with complex geometries that are otherwise difficult or impossible to create using other manufacturing processes, the foundry industry plays a significant role among other manufacturing industries. A new age for the foundry business can be ushered in by merging additive manufacturing technologies with the casting process. The traditional casting method is complicated, time-consuming, and requires expensive tooling. It is not cost-effective to make mould, cores, or patterns for small production runs. The combination of these two processes offers a new approach to investment casting, where 3D printing is used to create the wax patterns used in the investment casting process. This approach has several advantages, such as increased design flexibility, reduced lead time, and improved part quality. This study includes different AM technologies, materials, and their applications in casting industries. Recent developments, challenges, and future scope in the field of hybrid investment casting are discussed at the end of this paper.
Metal additive manufacturing of dental prostheses consisting of cobalt−chromium−tungsten (Co−Cr−W) alloys poses an alternative to investment casting. However, metal additive manufacturing processes ...like Laser Powder‐Bed Fusion (LPBF) can impact the elastic constants and the mechanical anisotropy of the resulting material. To investigate the phase compositions of mechanically different specimens in dependence of their postprocessing steps (e. g. heat treatment to relieve stress), the current study uses X‐ray Diffraction (XRD), Electron BackScatter Diffraction (EBSD), and Transmission Electron Microscopy (TEM) for phase identification. Our studies connect plastic deformation of Remanium star CL alloy with the formation of the hexagonal ϵ‐phase and heat treatment with the formation of the D024‐phase, while partially explaining previously observed differences in Young's moduli.
Abstract
Orthopedic implants had been widely used to treat bone fractures. One of the selected materials for an implant is austenitic stainless steel AISI 316L following the ASTM F138 standard. These ...implants had been produced locally in Indonesia using investment casting method. Even though the mechanical properties of local implant had met ASTM standards requirements, it was found to be lower in their properties as compared to the imported implant from developed countries. In order to compete with these imported products, local implant 316L was modified by reducing their grain size microstructures of about 83.17 µm on average to become finer grain through recrystallization mechanism. The mechanism can be triggered by thermal cycling treatment after 316L was subjected to cold rolling process. The cold rolling process will induce stored strain energy that affects the dislocation density. Different degrees of cold rolling reduction of 52%, 60%, 69%, 80%, and 90% will give different amounts of dislocation density that will affect the recrystallization stage during thermal cycling. It was found that after thermal cycling treatment at 900 C for 35 seconds with 4 cycles, homogenous full recrystallization was confirmed on 80% and 90% reduction degree samples. The average grain size of 80 and 90% reduction degree samples were decreased from 83.17 µm on average detected in the investment casting product to 3.26 µm and 2.87 µm, respectively. This had resulted also in increased average hardness from 159 HV
2
to 257 HV
2
and 267 HV
2
respectively. Conversely, only partial recrystallization was observed in the other degree of reduction samples. The obtained hardness provides lower value than 80% and 90% reduction degree with larger average grain size being detected on these samples.
In the selective electron beam melting approach an electron beam is used to partially melt the material powder. Based on the local high energy input, the solidification conditions and likewise the ...microstructures strongly deviate from conventional investment casting processes. The repeated energy input into the material during processing leads to the partial remelting of the already existing microstructure. To closer investigative this effect of partial remelting, in the present work the phase-field model is applied. In the first part the solidification of the referenced Ni–Al system is simulated in respect to selective electron beam melting. The model is calibrated such to reproduce the solidification kinetics of the superalloy CMSX-4. By comparison to experimental observations reported in the literature, the model is validated and is subsequently applied to study the effect of partial remelting. In the numerical approach the microstructures obtained from the solidification simulations are taken as starting condition. By systematically varying the temperature of the liquid built layer, the effect of remelting on the existing microstructure can be investigated. Based on these results, the experimental processing can be optimized further to produce parts with significantly more homogenous element distributions.
The casting of liquid metals to produce solid objects is a manufacturing process that has been practised for over 5000 years, with investment casting being one of the oldest known metal shaping ...methods. The technique itself has tremendous advantages in the production of quality components and the key benefits of accuracy, versatility and integrity. As a result the process is one of the most economic methods of forming a wide range of metal components. Environmental and economic pressures have, however, resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Optimisation of the mechanical and physical properties of the ceramic shell will be fundamental to achieving these aims. This paper sets out to summarise ceramic developments currently being implemented and to explore possible methods for the improvement of shell performance.
The microstructure of a cobalt-base alloy (Co-Cr-Mo) obtained by an investment casting process was studied. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of ...orthopedic implants owing to its high strength, good corrosion resistance, and excellent biocompatibility. This work focuses on the resulting microstructures arising from normal industrial environmental conditions. The characterization of the samples was carried out using optical microscopy, field emission scanning electron microscopy and energy-dispersive spectroscopy. In this study, the as-cast microstructure is an γ-Co (face-centered cubic) dendritic matrix with the presence of a secondary phase, such as M
23
C
6
carbides precipitated at grain boundaries and interdendritic zones. These precipitates are the main strengthening mechanism in this type of alloy. Other minority phases, such as the
σ
phase, were also detected, and their presence could be linked to the manufacturing process and environment.
Production of A6063/SiC–B4C hybrid composite using vacuum assisted block mould investment casting was investigated. Firstly, SiC–B4C hybrid preforms were fabricated in cylindrical shape. The ...preferred mean particle size of the SiC and B4C powders were 60 μm and 55 μm respectively. In early experiments, single powder ratio of 85% SiC and 15% B4C was selected to produce the tough preforms. Subsequently, the preforms were placed into the cylindrical shape gypsum bonded block investment moulds and A6063 alloy was infiltrated into the preforms using vacuum assisted (−105 Pa) casting machine. Porosity fraction of preforms was determined using Archimedes' test. The fabricated cast specimens were characterized using hardness tests, image analysis and SEM observations and EDX analysis. The result indicates that, by the vacuum assisted block mould investment casting technique, the infiltration of the preforms by molten metal was successfully realized.
A vibration technique is used in this study to explore the effect of low frequency vibration on the mechanical reliability of Al-7Si-Mg castings. The quality of castings is related to the number and ...the size of porosity and oxide film in thin wall investment casting. The quality of each method of casting (casting with and without vibration) was assessed by the density of the defects within the thin strips. Weibull distribution function is used to analyze the tensile strength data. The Weibull modulus is applied as a criterion to assess the mechanical reliability to identify the optimized casting condition. The results show that the effect of the vibration on the mechanical reliability is markedly dependent on acceleration of vibration, and the Weibull modulus is in the range of 12 to 12.7 when the acceleration is in range of 0 to 1
g
; however, in more than 1
g
, the range is 30–35.
The development of biomaterials, particularly metallic ones, is one of the focuses of the scientific community, mainly due to an increase of average life expectancy and an improvement of the casted ...materials combined with better mechanical properties and defect-free products. The use of cobalt alloys in applications, such as knee, hip, and dental prostheses, is the result of their good ability to maintain mechanical properties and biocompatibility over long periods of use. Numerical methods are becoming more important, as they help product improvement in a faster and economic way. This work focuses on the development of a numerical model in ProCAST®, comparing the shrinkage porosity and cooling curves with real castings. When correlating simulation results with available experimental data, it is possible to understand that the formulated model demonstrates an acceptable solution in terms of precision (shrinkage porosity and cooling curve). The alloy’s thermal properties and heat conditions were iteratively changed until the developed numerical model turned out a viable tool for this specific alloy when used in the investment casting process.
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