Design of stirling engine operating at low temperature difference

There are many sources of free energy available in the form of heat that is often simply wasted. The aim of this paper is to design and build a low temperature differential Stirling engine that would be powered exclusively from heat sources such as waste hot water or focused solar rays. A prototype is limited to a low temperature differential modification because of a choice of ABSplus plastic as a construction material for its key parts. The paper is divided into two parts. The first part covers a brief history of Stirling engine and its applications nowadays. Moreover, it describes basic principles of its operation that are supplemented by thermodynamic relations. Furthermore, an analysis of applied Fused Deposition Modelling has been done since the parts with more complex geometry had been manufactured using this additive technology. The second (experimental) part covers 4 essential steps of a rapid prototyping method - Computer Aided Design of the 3D model of Stirling engine using parametric modeller Autodesk Inventor, production of its components using 3D printer uPrint, assembly and final testing. Special attention was devoted to last two steps of the process since the surfaces of the printed parts were sandpapered and sprayed. Parts, where an ABS plus plastic would have impeded the correct function, had been manufactured from aluminium and brass by cutting operations. Remaining parts had been bought in a hardware store as it would be uneconomical and unreasonable to manufacture them. Last two chapters of the paper describe final testing, mention the problems that appeared during its production and propose new approaches that could be used in the future to improve the project.

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Mechanical implementation services for rapid prototyping

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1243/095440502760272467 ◽

2002 ◽

Vol 216 (8) ◽

pp. 1193-1199 ◽

Cited By ~ 4

Author(s):

S H Ahn ◽

S McMains ◽

C H Séquin ◽

P K Wright

Keyword(s):

Machine Tool ◽

Computer Aided Design ◽

Tool Path ◽

Complex Geometry ◽

Numerical Control ◽

Open Architecture ◽

Fused Deposition Modelling ◽

Cnc Machine ◽

Fused Deposition ◽

Trade Offs

Inspired by the metal oxide system implementation service (MOSIS) project, CyberCut is an experimental fabrication testbed for an Internet-accessible, computerized prototyping and machining service. Client-designers can create mechanical components, generally using our web-based computer aided design (CAD) system (available at http://cad.berkeley.edu ), and submit appropriate files to the server at Berkeley for process planning. CyberCut then utilizes an open-architecture, computer numerical control (CNC) machine tool for fabrication. Rapid tool path planning, novel fixturing techniques and sensor-based precision machining techniques allow the designer to take delivery of a component machined from high-strength materials with good tolerances, e.g. ±0.002in (0.05 mm). There are also instances where the complex geometry of a component cannot be prototyped on our three-axis machine tool. For these components use is made of solid freeform fabrication (SFF) technologies such as fused deposition modelling (FDM) to build a prototype of the design. Based on experience with this testbed, a new characterization of types of relationship, or ‘couplings’, between design and manufacturing has been developed using the three classifications ‘loose and repetitive’, ‘stiff and one-way’ or ‘strong and bidirectional’. These three couplings represent different trade-offs between ‘design flexibility’ and ‘guaranteed manufacturability’.

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Animal orthosis fabrication with additive manufacturing – a case study of custom orthosis for chicken

Rapid Prototyping Journal ◽

10.1108/rpj-03-2021-0054 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Wiktoria Maria Wojnarowska ◽

Jakub Najowicz ◽

Tomasz Piecuch ◽

Michał Sochacki ◽

Dawid Pijanka ◽

...

Keyword(s):

Veterinary Medicine ◽

Additive Manufacturing ◽

Computer Aided Design ◽

Three Dimensional ◽

Fused Deposition Modelling ◽

Content Type ◽

Fused Deposition ◽

Secondary Objective ◽

Traditional Manufacturing ◽

Aided Design

Purpose Chicken orthoses that cover the ankle joint area are not commercially available. Therefore, the main purpose of this study is to fabricate a customised temporary Ankle–Foot Orthosis (AFO) for a chicken with a twisted ankle using computer-aided design (CAD) and three-dimensional (3D) printing. The secondary objective of the paper is to present the specific application of Additive Manufacturing (AM) in veterinary medicine. Design/methodology/approach The design process was based on multiple sketches, photos and measurements that were provided by the owner of the animal. The 3D model of the orthosis was made with Autodesk Fusion 360, while the prototype was fabricated using fused deposition modelling (FDM). Evaluation of the AFO was performed using the finite element method. Findings The work resulted in a functional 3D printed AFO for chicken. It was found that the orthosis made with AM provides satisfactory stiffen and a good fit. It was concluded that AM is suitable for custom bird AFO fabrication and, in some respects, is superior to traditional manufacturing methods. It was also concluded that the presented procedure can be applied in other veterinary cases and to other animal species and other parts of their body. AM provides veterinary with a powerful tool for the production of well-fitted and durable orthoses for animals. Research limitations/implications The study does not include the chicken's opinion on the comfort or fit of the manufactured AFO due to communication issues. Evaluation of the final prototype was done by the researchers and the animal owner. Originality/value No evidence was found in the literature on the use of AM for chicken orthosis, so this study is the first to describe such an application of AM. In addition, the study demonstrates the value of AM in veterinary medicine, especially in the production of devices such as orthoses.

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Use of polymer concrete for large-scale 3D printing

Rapid Prototyping Journal ◽

10.1108/rpj-12-2019-0316 ◽

2021 ◽

Vol 27 (3) ◽

pp. 465-474

Author(s):

Martin Krčma ◽

David Škaroupka ◽

Petr Vosynek ◽

Tomáš Zikmund ◽

Jozef Kaiser ◽

...

Keyword(s):

3D Printing ◽

Large Scale ◽

Mechanical Performance ◽

Construction Material ◽

Polymer Concrete ◽

Fused Deposition Modelling ◽

Cast State ◽

Content Type ◽

Fused Deposition ◽

3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

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