Comparative study of the microstructures and mechanical properties of direct laser fabricated and arc-melted AlxCoCrFeNi high entropy alloys

High entropy alloys (HEA) are a relatively new metal alloy system that have promising potential in high temperature applications. These multi-component alloys are typically produced by arc-melting, requiring several remelts to achieve chemical homogeneity. Direct laser fabrication (DLF) is a rapid prototyping technique, which produces complex components from alloy powder by selectively melting micron-sized powder in successive layers. However, studies of the fabrication of complex alloys from simple elemental powder blends are sparse. In this study, DLF was employed to fabricate bulk samples of three alloys based on the AlxCoCrFeNi HEA system, where x was 0.3, 0.6 and 0.85M fraction of Al. This produced FCC, FCC/BCC and BCC crystal structures, respectively. Corresponding alloys were also produced by arc-melting, and all microstructures were characterised and compared longitudinal and transverse to the build/solidification direction by x-ray diffraction, glow discharge optical emission spectroscopy and scanning electron microscopy (EDX and EBSD). Strong similarities were observed between the single phase FCC and BCC alloys produced by both techniques, however the FCC/BCC structures differed significantly. This has been attributed to a difference in the solidification rate and thermal gradient in the melt pool between the two different techniques. Room temperature compression testing showed very similar mechanical behaviour and properties for the two different processing routes. DLF was concluded to be a successful technique to manufacture bulk HEA[U+05F3]s.

Automatic acceptance test case generation from essential use cases

Requirements validation is a crucial process to determine whether client-stakeholders' needs and expectations of a product are sufficiently correct and complete. Various requirements validation techniques have been used to evaluate the correctness and quality of requirements, but most of these techniques are tedious, expensive and time consuming. Accordingly, most project members are reluctant to invest their time and efforts in the requirements validation process. Moreover, automated tool supports that promote effective collaboration between the client-stakeholders and the engineers are still lacking. In this paper, we describe a novel approach that combines prototyping and test-based requirements techniques to improve the requirements validation process and promote better communication and collaboration between requirements engineers and clientstakeholders. To justify the potential of this prototype tool, we also present three types of evaluation conducted on the prototpye tool, which are the usability survey, 3-tool comparison analysis and expert reviews.

Influence of fill gap on flexural strength of parts fabricated by curved layer fused deposition modeling

Rapid Prototyping Techniques (RPT) have evolved over the last decade. Novel RP techniques are being developed to improve the overall properties of parts manufactured using RPT. One such technique is the Curved layer fused deposition modeling (CLFDM) which has been developed based on the conventional Fused Deposition Modeling (FDM) technique. The CLFDM technique has gained significant amount of attention as a result of its advantages such as increased flexural strength, reduction of the stair-stepping effect and the reduction in the number of layers, especially for thin shell-like structures. This paper studies the effects of fill gap (FG) on flexural strength and bead dimension, middle-plane cross section profiles and the fracture surface and compares the results to parts made using the traditional planar layer-by-layer approach. Also, in the end some meaningful and interesting future study areas both in hardware design and software development for the CLFDM are proposed.

The making of geometry

Geometry has been a source of inspiration in the design of the manmade world for millennia; it also provides representational means enabling development of a concept into a built object. In the past three decades computing methodologies have provided the designer with unprecedented tools to explore highly complex forms, create digital models and fabricate them. This paper describes a computational methodology for the transition of forms from abstract geometric configurations to physical objects: a parametric design process assists from the initial ideation to the final prototyping with 3D printing technologies. The five regular polyhedra are used as a case study; this paper explores how parametric based procedures develop these geometric shapes into digital models of structures to be fabricated in different sizes and materials.

Implementation of soft processor based SOC for JPEG compression on FPGA

With the advent of semiconductor process and EDA tools technology, IC designers can integrate more functions. However, to reduce the demand of time-to-market and tackle the increasing complexity of SoC, the need of fast prototyping and testing is growing. Taking advantage of deep submicron technology, modern FPGAs provide a fast and low-cost prototyping with large logic resources and high performance. So the hardware is mapped onto an emulation platform based on FPGA that mimics the behaviour of SOC. In this paper we use FPGA as a system on chip which is then used for image compression by 2-D DCT respectively and proposed SoC for image compression using soft core Microblaze. The JPEG standard defines compression techniques for image data. As a consequence, it allows to store and transfer image data with considerably reduced demand for storage space and bandwidth. From the four processes provided in the JPEG standard, only one, the baseline process is widely used. Proposed SoC for JPEG compression has been implemented on FPGA Spartan-6 SP605 evaluation board using Xilinx platform studio, because field programmable gate array have reconfigurable hardware architecture. Hence the JPEG image with high speed and reduced size can be obtained at low risk and low power consumption of about 0.699W. The proposed SoC for image compression is evaluated at 83.33MHz on Xilinx Spartan-6 FPGA.

A framework for programmatically designing user interfaces in javascript

Purpose – The purpose of this paper is to investigate the feasibility of creating a declarative user interface language suitable for rapid prototyping of mobile and Web apps. Moreover, this paper presents a new framework for creating responsive user interfaces using JavaScript. Design/methodology/approach – Very little existing research has been done in JavaScript-specific declarative user interface (UI) languages for mobile Web apps. This paper introduces a new framework, along with several case studies that create modern responsive designs programmatically. Findings – The fully implemented prototype verifies the feasibility of a JavaScript-based declarative user interface library. This paper demonstrates that existing solutions are unwieldy and cumbersome to dynamically create and adjust nodes within a visual syntax of program code. Originality/value – This paper presents the Guix.js platform, a declarative UI library for rapid development of Web-based mobile interfaces in JavaScript.

MaramaAIC: tool support for consistency management and validation of requirements

Requirements captured by requirements engineers (REs) are commonly inconsistent with their client’s intended requirements and are often error prone. There is limited tool support providing end-to-end support between the REs and their client for the validation and improvement of these requirements. We have developed an automated tool called MaramaAIC (Automated Inconsistency Checker) to address these problems. MaramaAIC provides automated requirements traceability and visual support to identify and highlight inconsistency, incorrectness and incompleteness in captured requirements. MaramaAIC provides an end-to-end rapid prototyping approach together with a patterns library that helps to capture requirements and check the consistency of requirements that have been expressed in textual natural language requirements and then extracted to semi-formal abstract interactions, essential use cases (EUCs) and user interface prototype models. It helps engineers to validate the correctness and completeness of the EUCs modelled requirements by comparing them to “best-practice” templates and generates an abstract prototype in the form of essential user interface prototype models and concrete User Interface views in the form of HTML. We describe its design and implementation together with results of evaluating our tool’s efficacy and performance, and user perception of the tool’s usability and its strengths and weaknesses via a substantial usability study. We also present a qualitative study on the effectiveness of the tool’s end-to-end rapid prototyping approach in improving dialogue between the RE and the client as well as improving the quality of the requirements.

The parametric making of geometry: the platonic solids

Geometry is a source of inspiration in the design and making of the manmade world. Computing techniques provide tools to explore complex forms: the research question is how computational tool can be systemised to assist with the translation of geometric concepts into physical objects. The purpose is to describe computational/manufacturing methods for creating digital models and physical objects from regular geometric configurations. The methods are based on parametric design, assisting from ideation to the generation of digital models with material specifications – using the five regular convex polyhedra as a case study. The results are comprised of digital models used for prototyping with 3D printing technologies and hybrid fabrication processes: the products are built geometric shapes ranging from body ornaments to sculptures. These procedures can be extended to generate designs based on irregular geometric shapes. Parametric-based methods are recommended in the digital modeling and fabrication of any geometric form.

Fabrication of biocompatible enclosures for an electronic implant using 3D printing

A variety of different approaches have been employed to enableimplantation of electronic medical microdevices. A novel method of producing low-cost, rapidly fabricated implantable enclosures from biocompatible silicone is presented in this paper. This method utilises 3D computer-aided design software to design and model the enclosures prior to fabrication. The enclosures are then fabricated through additive manufacturing from biocompatible silicone using a 3D bioprinter. In this paper, four different implantable enclosure designs are presented. A prototyping stage with three different prototypes is described, these prototype enclosures are then evaluated through submersion and operation tests. A final design is developed in response to the obtained results, and then evaluated in a long term temperature controlled submersion test. The evaluation results are presented and discussed.Several areas of future works are identified and discussed.

Additive manufacturing in the cycling industry: mainstream or gimmick?

INTRODUCTION. Additive manufacturing (AM) for various industries has been trailed, prototyped and used in limited production runs (Gibson, 2015). But considering additive manufacturing with metallic materials has been around for over 15 years the penetration into an industry such as cycling that values customisation and progressive design techniques has been quite limited. This case study looks at the potential of and why additive manufacturing has not progressed from concept development and prototyping into production and mainstream. Selective Laser Melting (SLM) additive manufacturing systems mainly use Stainless Steel 316 (SS316) and Titanium 6Al.4V (Ti64) as a baseline material; both these materials are extremely common in the custom and high volume bike industries. For the purposes of this article we will focus on smaller custom bike manufacturers who are typically more agile and open to high levels of customisation in their products. The study finds that whilst a high number of companies will experiment and prototype with additive manufacturing there is little evidence that the design and development process translates to ongoing production for sale to the consumer, this could be due to knowledge of design and fabrication techniques.

Industry case study: rapid prototype of mountain bike frame section

The purpose of this study is to detail a virtual and physical prototyping process to overcome a design constraint in the mountain bike industry. Through a series of techniques, 3D scanning, developing detailed CAD models, then through additive manufacturing processes, a solution wasdeveloped. The challenge in the industry is the constant geometrical changes of components; the trend has been that bike cranks are becoming narrower due to biomechanical factors and tyres are becoming wider due to rider preferences and increased grip. This change in geometry results in metal tubes that can no longer be deformed without exceeding the minimum bend radius for the material. As such exceeding the minimum bend radius will induce early performance failure and geometrical (aesthetic) defects. The solution is an additivemanufactured part that can be substituted into the process without disrupting the entire conventional build process of a customised bike build.

Evolution of 3D printed soft actuators

Developing soft actuators and sensors by means of 3D printing has become an exciting research area. Compared to conventional methods, 3D printing enables rapid prototyping, custom design, and single-step fabrication of actuators and sensors that have complex structure and high resolution. While 3D printed sensors have been widely reviewed in the literature, 3D printed actuators, on the other hand, have not been adequately reviewed thus far. This paper presents a comprehensive review of the existing 3D printed actuators. First, the common processes used in 3D printing of actuators are reviewed. Next, the existing mechanisms used for stimulating the printed actuators are described. In addition, the materials used to print the actuators are compared. Then, the applications of the printed actuators including soft-manipulation of tissues and organs in biomedicine and fragile agricultural products, regenerative design, smart valves, microfluidic systems, electromechanical switches, smart textiles, and minimally invasive surgical instruments are explained. After that, the reviewed 3D printed actuators are discussed in terms of their advantages and disadvantages considering power density, elasticity, strain, stress, operation voltage, weight, size, response time, controllability, and biocompatibility. Finally, the future directions of 3D printed actuators are discussed.

Computation and fabrication of scaled prototypes

The formal, functional, and material attributes of design are routinely investigated through the construction of physical models and scaled prototypes. With the increasing adoption of computational workflows, the digital to physical translation process is central to the construction of scaled prototypes. However, the choice of methods, tools and materials for computational prototyping is a developing area. Therefore a systematic body of knowledge on the benefits and costs of multiple methods of computational prototyping for the construction of physical prototypes need to be identified. This paper addresses the prototyping process through the comparison of three computational methods of fabrication through the modelling, analysis and construction of a Gaussian Vault. It reports on the process of digital to physical construction using additive manufacturing, surface fabrication and structural component models. The Gaussian Vault offers a unique set of geometric, structural and physical characteristics for testing all three methods of prototyping. The size, shape and proportion of vault prototypes are rapidly generated and tested. The design geometry, material properties and physical construction of the Gaussian Vault are realised using commonly used practice workflows comprising parametric modelling and analysis of geometry, model rationalisation with material characteristics and finally the use of digital fabrication methods. Comparison of the results identifies the characteristics, benefits and limitations of the three approaches. Finally the paper discusses the digital to physical translation processes and summarises the characteristics, benefits and issues encountered in each.