Allan Rennie

Electroforming of Rapid Prototyping Mandrels for Electro-Discharge Machining Electrodes

The process of creating injection mould cavities, possible by a variety of methods, can be a lengthy one. The most common technique to obtain complex cavities is by utilising electro-discharge machining. This allows for the production of cavities that could not normally be produced by conventional machining methods. However, some electrodes for use in the electro-discharge machining process can themselves be difficult, and sometimes impossible to machine. By applying electroforming to the relatively young technology of rapid prototyping, complex electrodes can be produced in fairly reasonable timescales. This paper explains the work being conducted in this area by the authors, and the use of differing RP technologies in the production of these electroforms. It has been found that thin walled (≤1.5 mm) copper electroforms backed up with suitable filler materials are ideal for use as electro-discharge machining electrodes.

SME application of LCA‐based carbon footprints

Following a brief introduction about the need for businesses to respond to climate change, this paper considers the development of the phrase ‘carbon footprint’. Widely used definitions are considered before the authors offer their own interpretation of how the term should be used. The paper focuses on the contribution small and medium sized enterprises (SMEs) make to the economy and their level of influence in stimulating change within organisations. The experience of an outreach team from the Engineering Department of a UK university is used which draws on the experience of delivering regional economic growth projects funded principally through the European Regional Development Fund. Case studies are used including the development of bespoke carbon footprints for SMEs from an initiative delivered by the outreach team. Limitations of current carbon footprints are identified based on this higher education‐industry knowledge exchange mechanism around three main themes of scope, the assessment method and conversion factors. Evidence and discussions are presented that conclude with the presentation of some solutions based on the work undertaken with SMEs and a discussion on the merits of the two principally used methodologies: life‐cycle analysis and economic input–output assessment.

Additive manufacturing technology and material selection for direct manufacture of products based on computer aided design geometric feature analysis

This paper presents research into the development of an algorithm developed in a Visual Basic programming environment that aids in the selection of materials processed using additive manufacturing (AM) technologies. AM technologies such as selective laser sintering (SLS) and fused deposition modelling (FDM) have limitations on the materials available to them and each system has factors that limit the geometric freedom of the components that they can produce. Thus, materials capable of being processed on these types of technology can be selected through a method of traversing the geometric features of a computer aided design (CAD) model and performing an analysis of each individual feature’s attributes. The algorithm developed for this research uses data based on minimum feature size and a model bounding box as criteria in the selection of suitable materials. Through integration with an existing commercially available CAD software package, a component can be automatically analysed for its geometric feature properties and attributes, returning suitable AM systems and material information for selection by the operator. A number of case studies are presented that highlight the successful operation of the AM technology and material selection tool that has been developed.

The Business Model for the Functional Rapid Manufacturing Supply Chain

Abstract The use of the Rapid Manufacturing (RM) technologies to manufacture end used product has become a more viable proposition these days than it was in the past. However, the characteristics of the technology allow for unconventional usage and subsequent supply chain support requirements. Therefore, it can be argued that the RM supply chain concepts have the potential room for further evolution. This research focuses on the possibility and structure of a business model tailored for the unconventional RM supply chain requirements. In this regard, the paper proposes the Virtual Trading System or VTS, which is an e-business platform that could potentially provide an alternative to the RM industry, in terms of supply chain functionality. The research outlines the structure of such a business model in detail, based on the requirements of the RM industry.

Rapid prototyping and flow simulation applications in design of agricultural irrigation equipment: Case study for a sample in-line drip emitter

In this study, a 3D CAD solid model of a sample agricultural irrigation emitter was created and the flow behaviour was simulated in its labyrinth channels by using a flow simulation technique. Referenced by the original design, the channel geometry was modified and the emitter was re-fabricated using rapid prototyping/additive manufacturing techniques. The flow behaviour is then re-investigated based on the re-shaped channel geometry of the labyrinth structure. The predetermined optimum pressure in the pipe was validated experimentally for both the original design and modified designs. As a result, the optimum pressure in the pipe and the flow characteristics for original both the design and modified designs of the emitter were validated. This study contributes to further research into the development of agricultural irrigation equipment aided through the utilisation of additive manufacturing and computer aided engineering tools.

Computer aided material selection for additive manufacturing materials

The ease at which products can be manufactured directly from digital data in one step removing the need for tool design or manufacturing set up leads to a scenario where highly individualised and complex products can be created that avoid cost and time penalties enabling products that are competitive with mass produced equivalents. The reality of this scenario is that, although additive manufacturing (AM) offers a real solution to the problem of producing complex or customised products that are competitive with mass produced equivalents, information regarding available AM material and process capability is fragmented and difficult to generate. This stands as a suitable barrier to adopting AM strategies. This paper presents a knowledge system contained within an existing CAD environment, in this case SolidWorks CAD software, which can be accessed within the existing graphical user interface, enabling the selection of appropriate AM materials and process technology from user generated model data.

Using Additive Manufacturing Effectively: A CAD Tool to Support Decision Making

Additive manufacturing (AM) describes the use of layer manufacturing technologies (LMT) to directly produce end use parts. More commonly, LMT have been used as a method to accurately and quickly produce prototype models sometimes referred to as rapid prototyping or 3D printing. Presently, however, LMT is utilised to produce polymeric and metallic parts directly from computer aided design (CAD) model data. While advancements in machine and material technology are reasons for the ability to directly manufacture components using LMT over producing only models and prototypes, the lack of available and reliable data concerning these advancements limits the effective adoption of the technology as a substitute for other manufacturing methods. To decide when AM can be used effectively, data needs to be at the disposal of designers so that they may make decisions about manufacturing of the parts they design. Current trends in CAD software development bring design support tools into the CAD environment, as a method to increase effectiveness into the design process. A support system to guide effective use of LMT would follow this trend and give instant access to information and support decision making for designers in a CAD environment. This research collates, through information gathering and experimentation, process and material data for layer technologies and aims to develop a CAD tool for the support and guidance in decision making about appropriate and effective use of AM.

Horizon 2020 TWEETHER project for W-band high data rate wireless communications

The outstanding demand of high data rate in wireless network is exceeding the actual capacity making the microwave region of the spectrum inadequate for the future needs. The millimeter wave region has been demonstrated suitable for multi-gigabit transmission. Unfortunately, technological issues still prevent its adequate exploitation. The Horizon 2020 TWEETHER project “Traveling wave tube for W-band wireless networks with high data rate distribution, spectrum and energy efficiency” aims to respond to this challenge. A novel W-band traveling wave tube will be the core of the system.

An investigation into the use of additive manufacture for the production of metallic bipolar plates for polymer electrolyte fuel cell stacks

The bipolar plate is of critical importance to the efficient and long lasting operation of a polymer electrolyte fuel cell (PEMFC) stack. With advances in membrane electrode assembly design, greater attention has been focused on the bipolar plate and the important role it plays. Although carbon composite plates are a likely candidate for the mass introduction of fuel cells, it is metallic plates made from thin strip materials which could deliver significant advantages in terms of part cost, electrical performance and size. However, there are some disadvantages. Firstly, interfacial stability of the metal interconnect is difficult to achieve. Secondly, and the issue addressed here, is the difficultly and cost in developing new plate designs when there are very significant tooling costs associated with manufacture. The use of selective laser melting (SLM: an additive manufacturing technique) was explored to produce metallic bipolar plates for PEMFC as a route to inexpensively test several plate designs without committing to tooling. Crucial to this was proving that, electrically, bipolar plates fabricated by SLM behave similarly to those produced by conventional manufacturing techniques. This research presents the development of a small stack to compare the short term performance of metallic plates made by machining against those made by SLM. Experimental results demonstrate that the cell performance in this case was unaffected by the manufacturing method used and it is therefore concluded that additive manufacturing could be a very useful tool to aid the rapid development of metallic bipolar plate designs.

Design for Manufacture Using Functional Analysis and CAD Mould Simulation for Rapid Prototyping and Rapid Tooling

The pressure of time, quality and cost, together with increasing product variety, more customised products and worldwide competition is driving technology development and implementation in the area of Rapid Manufacturing (RM). Traditionally, the manufacture of tooling for both prototype parts and production components represents one of the longest and most costly phases in the development of most new products. The cost and time implications of the tooling process are particularly problematic for low-volume products aimed at niche markets, or alternatively for rapidly changing high-volume products. Rapid Prototyping (RP) and Rapid Tooling (RT) have the potential to dramatically shorten the time required to produce functional prototypes or products. Functional Analysis (FA) plays a key role in the design process of the actual tools, allowing for innovative solutions that can be achieved with RP and RT. This paper presents a FA methodology to design for manufacture (DFM) based on RP- and RT-specific characteristics, aimed at improving process efficiency, streamline energy consumption, use of volume material, usage of structural innovative lightweight materials, decrease overall costs and improve product quality. Design for Rapid Manufacturing (DFRM) allows for geometric freedom, leading to changes of the overall design process, thus enhancing the FA process. FA begins with stating the need, in a DFRM case that translates into diagnosis, the determination of the manufacturability of the present product and comparison with similar products on the market. Setting objectives, in terms of production costs, quality, flexibility, risk, lead-time, efficiency, and environment are other milestones in FA. Actual function definition involves defining the main functions of the product and their interactions. Clarifying the evaluation parameters, setting criteria levels and technical dimensioning is done for each of the main product functions. The conceptual design process then follows a top-down sequence: corporate, family, structural and component levels. Evaluation and selection of the optimal concept resulting from the FA consists of assessing the manufacturability of the proposed concepts in terms of the DFM objectives. The selected best fit concept is translated to design in the last stage, when the chosen concept is communicated to the development team. The detailed design is carried out in parallel to marketing and product development. Targeted FA is shown to enable generation of innovative solutions, while improving manufacturability. The present research stands as a starting point in the development of product design methodologies that use RP and RT applications for manufacturing physical products.