Ondřej Vaverka, Daniel Koutny and David Palousek
This paper aims to present the design process, manufacturing and testing of a prototype of an axle carrier for Formula Student race car. The axle carrier is topologically…
Abstract
Purpose
This paper aims to present the design process, manufacturing and testing of a prototype of an axle carrier for Formula Student race car. The axle carrier is topologically optimized and additively manufactured using selective laser melting (SLM).
Design/methodology/approach
The shape of the axle carrier was created in three design stages using topology optimization and four additional design stages based on finite element calculations and experimental testing. Topology optimization was performed on the basis of relevant load cases. The sixth design stage was manufactured by SLM and then tested on a loading device together with photogrammetry measurement to obtain the real deformation. Measured deformations were compared with deformation calculated by the finite element method (FEM), verified and experiences used in the last design stage.
Findings
An additively manufactured axle carrier has a minimal safety factor of 1.2 according to experimental testing. The weight and maximal deformations are comparable with the milled part, although the material has about 50 per cent worse yield strength. The topologically optimized axle carrier proved big potential in the effective distribution of material and the improvement of toughness.
Practical implications
This paper helps the Formula Student team to enhance the driving performance while keeping low weight. It also improves further development and upgrading of the race car.
Originality/value
The whole design of the topologically optimized part was investigated – from estimation of the loads to experimental verification of FEM analysis on real part.
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David Palousek, Martin Kocica, Libor Pantelejev, Lenka Klakurkova, Ladislav Celko, Daniel Koutny and Jozef Kaiser
Materials with a high thermal conductivity, such as Cu-alloys hold the most interest to the plastic moulding industry. Additive manufacturing (AM), especially selective laser…
Abstract
Purpose
Materials with a high thermal conductivity, such as Cu-alloys hold the most interest to the plastic moulding industry. Additive manufacturing (AM), especially selective laser melting (SLM) of metals, allows the production of parts with complicated internal cooling and increased production efficiency. The portfolio of alloys for metal AM is limited and still missing process parameters for the processing of copper alloys. This paper aims to preview the process parameters of high-strength alloy Cu7.2Ni1.8Si1Cr processed by SLM.
Design/methodology/approach
An experimental approach is adopted to investigate porosity and mechanical properties of SLM specimens and its comparison with standard material AMPCOLOY 944. Optimization of porosity was performed using line and cube specimens; mechanical properties and microstructure were evaluated by tensile testing and metallography.
Findings
Optimum processing parameters for fabrication of Cu-alloy specimens with a relative density of 99.95 per cent were identified, and no cracks were detected. Mechanical testing of SLM specimens showed the ultimate tensile strength, proof stress of 0.2 and elongation of 380, 545 MPa and 16.9 per cent. The alloy is suitable for laser AM, thanks to its processability at a relatively high laser scanning speeds and thus its promising price of part/costs ratio.
Research limitations/implications
The paper describes the initial state of research – the follow-up tests focussed on mechanical testing, fatigue and statistical evaluation need to be conducted. The process parameters are developed only for bulk geometry – optimal setup for lattice structures and thin walls has not been explored yet.
Practical implications
The research findings in this work could be used for production of 3D printed parts and after the tuning of additional parameters, e.g. for up- and down-skin zones, could be used for special application such as energy exchange.
Originality/value
This work produces the processing of new material suitable for laser AM. Cu7.2Ni1.8Si1Cr alloy could be the prospective material from the group of Cu alloys suitable for moulds manufacturing and thermal applications.
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David Palousek, Jiri Rosicky, Daniel Koutny, Pavel Stoklásek and Tomas Navrat
– The purpose of this paper is to describe a manufacturing methodology for a wrist orthosis. The case study aims to offer new approaches in the area of human orthoses.
Abstract
Purpose
The purpose of this paper is to describe a manufacturing methodology for a wrist orthosis. The case study aims to offer new approaches in the area of human orthoses.
Design/methodology/approach
The article describes the utilization of rapid prototyping (RP), passive stereo photogrammetry and software tools for the orthosis design process. This study shows the key points of the design and manufacturing methodology. The approach uses specific technologies, such as 3D digitizing, reverse engineering and polygonal-surface software, FDM RP and 3D printing.
Findings
The results show that the used technologies reflect the patient's requirements and also they could be an alternative solution to the standard method of orthosis design.
Research limitations/implications
The methodology provides a good position for further development issues.
Practical implications
The methodology could be usable for clinical practice and allows the manufacturing of the perfect orthosis of the upper limb. The usage of this methodology depends on the RP system and type of material.
Originality/value
The article describes a particular topical problem and it is following previous publications in the field of human orthoses. The paper presents the methodology of wrist orthosis design and manufacturing. The paper presents an alternative approach applicable in clinical practice.
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Rafael Moreno, Diego Carou, Daniel Carazo-Álvarez and Munish Kumar Gupta
3D printing is gaining attention in the medical sector for the development of customized solutions for a wide range of applications such as temporary external implants. The…
Abstract
Purpose
3D printing is gaining attention in the medical sector for the development of customized solutions for a wide range of applications such as temporary external implants. The materials used for the manufacturing process are critical, as they must provide biocompatibility and adequate mechanical properties. This study aims to evaluate and model the influence of the printing parameters on the mechanical properties of two biocompatible materials.
Design/methodology/approach
In this study, the mechanical properties of 3D-printed specimens of two biocompatible materials (ABS medical and PLActive) were evaluated. The influence of several printing parameters (infill density, raster angle and layer height) was studied and modelled on three response variables: ultimate tensile strength, deformation at the ultimate tensile strength and Young’s modulus. Therefore, statistical models were developed to predict the mechanical responses based on the selected printing parameters.
Findings
The used methodology allowed obtaining compact models that show good fit, particularly, for both the ultimate tensile strength and Young’s modulus. Regarding the deformation at ultimate tensile strength, this output was found to be influenced by more factors and interactions, resulting in a slightly less precise model. In addition, the influence of the printing parameters was discussed in the work.
Originality/value
The presented paper proposed the use of statistical models to select the printing parameters (infill density, raster angle and layer height) to optimize the mechanical response of external medical aids. The models will help users, researchers and firms to develop optimized solutions that can reduce material costs and printing time but guaranteeing the mechanical response of the parts.
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Steffan Daniel and Dominic Eggbeer
This paper aims to present novel techniques for designing maxillofacial prostheses using computer-aided design (CAD) and additive manufacture (AM), focusing on the integration of…
Abstract
Purpose
This paper aims to present novel techniques for designing maxillofacial prostheses using computer-aided design (CAD) and additive manufacture (AM), focusing on the integration of osseointegrated retention components. A fully computer-aided approach is considered as a major step towards reducing patient consultation time and an efficient workflow.
Design/methodology/approach
The workflow was illustrated through a phantom model. 3D laser scanning was used to capture the phantom anatomy and pre-fabricated geometric features, which enabled the implant positions to be precisely reverse engineered in the data. A novel CAD workflow was used to design the retention mechanisms and a mould. The individual components were fabricated using AM. A definitive silicone prosthesis that incorporated a bar/clip retention mechanism was then fabricated.
Findings
The research demonstrated that retention components can be integrated into prostheses using appropriate CAD and AM technologies.
Originality/value
This study demonstrates the feasibility of a computer-aided workflow for designing facial prostheses that incorporate osseointegrated retention mechanisms. Novel techniques were developed to: digitise abutment details using custom scanning locators; design retention components; manufacture retention components using AM; integrate retention components into a CAD and AM prosthesis mould. This overcomes limitations identified in previously published cases and demonstrated significant potential to reduce patient consultation time and create a clinically viable process.
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Siamak Ghadami-Badrlou, Mohsen Khajehzadeh and Mohammad Reza Razfar
This paper aims to study the elasto-dynamic behavior of additively manufactured metallic lattice implants and compare them with human lower-body bone. This work is a step toward…
Abstract
Purpose
This paper aims to study the elasto-dynamic behavior of additively manufactured metallic lattice implants and compare them with human lower-body bone. This work is a step toward producing implants with high similarity of material properties to bone by developing a dynamic design approach.
Design/methodology/approach
A suitable topology was selected and admissible design space was established. Implants were fabricated by selective laser melting. Material dynamics, including elastic modulus, damping and natural frequency, were analyzed with experimental and finite element method methodology.
Findings
Generally, porosity improves dynamic properties up to an optimum point, which depends on printability, that is, ∼70%. Regarding elastic modulus and natural frequency, it is possible to achieve enough similarity with bone. But, considering damping, the similarity is <23% and <12% with dry and fresh bone, respectively. Damping and strain rate sensitivity increase with porosity. The natural frequency decreases with porosity. Bone ingrowth into lattice implants improves damping substantially while increasing elastic modulus.
Originality/value
Designers, dominantly had quasi-static approach, which considered only elastic modulus. But, the human body is a dynamic structure and experiences dynamic loads; meanwhile, bone, with its damping and natural frequency, regulates dynamic events like shock absorption and elastic wave filtering. Importantly, bone cells sense no load in quasi-static loading and must receive impact loads near their natural frequencies and special accelerations to conduct optimum mechanotransduction. So, it is necessary to develop a dynamic strategy which is comprehensive and describes bone duties.