Search results
1 – 10 of over 9000Javier Navarro, Matthew Din, Morgan Elizabeth Janes, Jay Swayambunathan, John P. Fisher and Maureen L. Dreher
This paper aims to study the effects of part orientation during the 3D printing process, particularly to the case of using continuous digital light processing (cDLP) technology.
Abstract
Purpose
This paper aims to study the effects of part orientation during the 3D printing process, particularly to the case of using continuous digital light processing (cDLP) technology.
Design/methodology/approach
The effects of print orientation on the print accuracy of microstructural features were assessed using microCT imaging and mechanical properties of cDLP microporous scaffolds were characterized under simple compression and complex biaxial loading. Resin viscosity was also quantified to incorporate this factor in the printing discussion.
Findings
The combined effect of print resin viscosity and the orientation and spacing of pores within the structure alters how uncrosslinked resin flows within the construct during cDLP printing. Microstructural features in horizontally printed structures exhibited greater agreement to the design dimensions than vertically printed constructs. While cDLP technologies have the potential to produce mechanically isotropic solid constructs because of bond homogeneity, the effect of print orientation on microstructural feature sizes can result in structurally anisotropic porous constructs.
Originality/value
This work is useful to elucidate on the specific capabilities of 3D printing cDLP technology. The orientation of the part can be used to optimize the printing process, directly altering parameters such as the supporting structures required, print time, layering, shrinkage or surface roughness. This study further detailed the effects on the mechanical properties and the print accuracy of the printed scaffolds.
Details
Keywords
Marek Pagac, David Schwarz, Jana Petru and Stanislav Polzer
Mechanical properties testing of the hyperelastic thermoplastic polyurethane (TPU) produced by the continuous digital light processing (CDLP) method of additive manufacturing…
Abstract
Purpose
Mechanical properties testing of the hyperelastic thermoplastic polyurethane (TPU) produced by the continuous digital light processing (CDLP) method of additive manufacturing. Primarily, this paper aims to verify that 3D printed TPU still satisfies commonly assumed volumetric incompressibility and material isotropy in elastic range. The secondary aim is to investigate the accuracy and reproducibility of the CDLP method.
Design/methodology/approach
Cylindrical samples were printed and subjected to a volumetric compression test to reveal their bulk modulus K and maximal theoretical porosity (MTP). Dog bone specimens were oriented along different axes and printed. Their dimensions were measured, and they were subjected to cyclic uniaxial tests up to 100% strain to reveal the level of stress softening and possible anisotropy. The hyperelastic Yeoh model was fitted to the mean response.
Findings
The authors measured the bulk modulus of K = 1851 ± 184 MPa. The mean MTP was 0.9 ± 0.5%. The mean response was identical in both directions and the data could be fitted by the isotropic third order Yeoh function with R^2 = 0.996. The dimensions measurement revealed the largest error (above 5%) in the direction perpendicular to the direction of the digital light projection while the dimensions in other two dimensions were much more accurate (0.75 and 1%, respectively).
Practical implications
The TPU printed by CDLP can be considered and modelled as isotropic and practically volumetrically incompressible. The parts in the printing chamber should be positioned in a way that the important dimensions are not parallel to the direction of the digital light projection.
Originality/value
The authors experimentally confirmed the volumetric incompressibility and mechanical isotropy of the TPU printed using the CDLP method.
Details
Keywords
João Maranha, Paulo Jorge Nascimento, Tomaz Alexandre Calcerano, Cristóvão Silva, Stefanie Mueller and Samuel Moniz
This study provides an up-to-date review of additive manufacturing (AM) technologies and guidance for selecting the most appropriate ones for specific applications, taking into…
Abstract
Purpose
This study provides an up-to-date review of additive manufacturing (AM) technologies and guidance for selecting the most appropriate ones for specific applications, taking into account the main features, strengths, and limitations of the existing options.
Design/methodology/approach
A literature review on AM technologies was conducted to assess the current state-of-the-art. This was followed by a closer examination of different AM machines to gain a deeper insight into their main features and operational characteristics. The conclusions and data gathered were used to formulate a classification and decision-support framework.
Findings
The findings indicate the building blocks of the selection process for AM technologies. Furthermore, this work shows the suitability of the existing AM technologies for specific cases and points to opportunities for technological and decision-support improvements. Lastly, more standardization in AM would be beneficial for future research.
Practical implications
The proposed framework offers valuable support for decision-makers to select the most suitable AM technologies, as demonstrated through practical examples of its utilization. In addition, it can help researchers identify the limitations of AM by pinpointing applications where existing technologies fail to meet the requirements.
Originality/value
The study offers a novel classification and decision-support framework for selecting AM technologies, incorporating machine characteristics, process features, physical properties of printed parts, and costs as key features to evaluate the potential of AM. Additionally, it provides a deeper understanding of these features as well as the potential opportunities for AM and its impact on various industries.
Details
Keywords
Wei-Ting Chang, Huang-Jan Hsu, Cho-Pei Jiang, Shyh-Yuan Lee and Yuan-Min Lin
The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake dye (TL…
Abstract
Purpose
The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake dye (TL dye) on thickness, flexural strength, flexural modulus and surface details of the 3D-printed resin.
Design/methodology/approach
Influences of different concentrations of n-TiO2 and TL dye in light-cured resin formulations for 3D printing (3DP) application were evaluated, including curing thickness, flexural strength and surface details under scanning electron microscopy.
Findings
The polymerization thickness of samples containing both n-TiO2 and TL dye was lower compared to samples with TL dye solely. Samples containing more n-TiO2 and more TL dye exhibited lower flexural strength and modulus. Ramp models showed that for samples containing 1 per cent TL dye, when their n-TiO2 content increased from 1 to 5 per cent, surface laminate structures became sharper. However, when the TL dye content doubled to 2 per cent, the surface laminate structures were indefinite compared to 1 per cent TL dye-containing counterparts.
Originality value
In visible-light 3DP, light controlling system in cooperate dye with high refractive particles provides better energy distribution and scattering control. High refractive particles, dyes and light exposure time had influenced the surface resolution and mechanical properties of the 3DP products.
Details
Keywords
Sathies T., Senthil P. and Anoop M.S.
Fabrication of customized products in low volume through conventional manufacturing incurs a high cost, longer processing time and huge material waste. Hence, the concept of…
Abstract
Purpose
Fabrication of customized products in low volume through conventional manufacturing incurs a high cost, longer processing time and huge material waste. Hence, the concept of additive manufacturing (AM) comes into existence and fused deposition modelling (FDM), is at the forefront of researches related to polymer-based additive manufacturing. The purpose of this paper is to summarize the research works carried on the applications of FDM.
Design/methodology/approach
In the present paper, an extensive review has been performed related to major application areas (such as a sensor, shielding, scaffolding, drug delivery devices, microfluidic devices, rapid tooling, four-dimensional printing, automotive and aerospace, prosthetics and orthosis, fashion and architecture) where FDM has been tested. Finally, a roadmap for future research work in the FDM application has been discussed. As an example for future research scope, a case study on the usage of FDM printed ABS-carbon black composite for solvent sensing is demonstrated.
Findings
The printability of composite filament through FDM enhanced its application range. Sensors developed using FDM incurs a low cost and produces a result comparable to those conventional techniques. EMI shielding manufactured by FDM is light and non-oxidative. Biodegradable and biocompatible scaffolds of complex shapes are possible to manufacture by FDM. Further, FDM enables the fabrication of on-demand and customized prosthetics and orthosis. Tooling time and cost involved in the manufacturing of low volume customized products are reduced by FDM based rapid tooling technique. Results of the solvent sensing case study indicate that three-dimensional printed conductive polymer composites can sense different solvents. The sensors with a lower thickness (0.6 mm) exhibit better sensitivity.
Originality/value
This paper outlines the capabilities of FDM and provides information to the user about the different applications possible with FDM.
Details
Keywords
Abdul Wahab Hashmi, Harlal Singh Mali and Anoj Meena
The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the…
Abstract
Purpose
The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts.
Design/methodology/approach
There are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness.
Findings
In this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories.
Research limitations/implications
The review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy.
Originality/value
This paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts.
Graphical abstract of surface quality improvement methods
Details
Keywords
Jinghua Xu, Kunqian Liu, Zhi Liu, Fuqiang Zhang, Shuyou Zhang and Jianrong Tan
Most rapid prototyping (RP) relies on energy fields to handle materials, among which electricity has been much more utilized, resulting in distinctive responsiveness of…
Abstract
Purpose
Most rapid prototyping (RP) relies on energy fields to handle materials, among which electricity has been much more utilized, resulting in distinctive responsiveness of non-linear, overshoot, variable inertia, etc. The purpose of this paper is to eliminate the drawbacks of array nozzle clogging, stringing, melt sagging, particularly in multi-material RP, by focusing on the electrothermal response so as to adaptively distribute thermal more accurate, rapid and balanced.
Design/methodology/approach
This paper presents an electrothermal response optimization method of nozzle structure for multi-material RP based on fuzzy adaptive control (FAC). The structural, physical and control model are successively logically built. The fractional order electrothermal model is identified by Riemann Liouville fractional differential equation, using the bisection method to approximate the physical model via least square method to minimize residual sum of squares. The FAC is thereafter implemented by defining fuzzy proportion integration differentiation control rules and fuzzy membership functions for fuzzy inference and defuzzification.
Findings
The transient thermodynamic and structural statics, as well as flow field analysis, are conducted. The response time, mean temperature difference and thermal deformation can be found using thermal-solid coupling finite element analysis. In physical experimental research, temperature change, together with material extrusion loading, were measured. Both numerical and physical studies have revealed findings that the electrothermal responsiveness varies with the three-dimensional structure, materials and energy sources, which can be optimized by FAC.
Originality/value
The proposed FAC provides an optimization method for extrusion-based multi-material RP between the balance of thermal response and energy efficiency through fulfilling potential of the hardware configuration. The originality may be widely adopted alongside increasing requirements on high quality and high efficiency RP.
Details
Keywords
Yihao Zheng, Yancheng Wang, Roland K. Chen, Sagar Deshpande, Noah S. Nelson, Steven R. Buchman and Albert J. Shih
To obtain a vascularized autologous bone graft by in-vivo tissue transformation, a biocompatible tissue transformation mold (TTM) is needed. An ideal TTM is of high geometric…
Abstract
Purpose
To obtain a vascularized autologous bone graft by in-vivo tissue transformation, a biocompatible tissue transformation mold (TTM) is needed. An ideal TTM is of high geometric accuracy and X-ray radiolucent for monitoring the bone tissue formation. The purpose of this study is to present the TTM design and fabrication process, using 3D reconstruction, stereolithography (SLA) and silicone molding.
Design/methodology/approach
The rat mandible, the targeted bone graft, was scanned by micro-computed tomography (CT). From the micro-CT images, the 3D mandible model was identified and used as the cavity geometry to design the TTM. The TTM was fabricated by molding the biocompatible and radiolucent silicone in the SLA molds. This TTM was implanted in a rat for in vivo tests on its biocompatibility and X-ray radiolucency.
Findings
SLA can fabricate the TTM with a cavity shape that accurately replicates that of the rat mandible. The bone formation inside of the silicone TTM can be observed by X-ray. The TTM is feasible for in vivo tissue transformation for vascularized bone reconstruction.
Research limitations/implications
Research of the dimensional and geometrical accuracy of the TTM cavity is required in the future study of this process.
Practical implications
The TTM fabricated in this presented approach has been used for in-vivo tissue transformation. This technique can be implemented for bone reconstruction.
Originality/value
The precision fabrication of the TTMs for in-vivo tissue transformation into autogenous vascularized bone grafts with complex structures was achieved by using SLA, micro-CT and silicone molding.
Details
Keywords
Benjamin Faro, Babak Abedin, Dilek Cetindamar and Farhad Daneshgar
The research aims to understand the co-existence of nimbleness and resilience in a continuous digital transformation, along with the dynamic capabilities needed to balance the…
Abstract
Purpose
The research aims to understand the co-existence of nimbleness and resilience in a continuous digital transformation, along with the dynamic capabilities needed to balance the challenges of their co-existence.
Design/methodology/approach
The current study draws on dialogical action design research (D-ADR) to investigate interactions among practitioners and executives. Data are collected from a major Australian financial services organisation (FSO) and many international experts.
Findings
The study presents a framework, the continuous transformation model (CTM), to describe digital transformation within an FSO context, emphasising nimbleness and resilience as its foundational pillars. This framework facilitates the identification of the critical role of organisational capabilities in managing continuous digital transformation, supported by dynamic IT capabilities. More importantly, the findings underscore how these capabilities enable managers to effectively balance the coexistence of nimbleness and resilience.
Research limitations/implications
The CTM contributes to the enterprise information systems literature by offering a coherent understanding of balancing resilience and nimbleness to succeed in digital transformation. In particular, the research model elucidates the relationship between dynamic capabilities and continuous digital transformations.
Practical implications
Digital transformations are not a one-off exercise. Managers in the FSO context must cultivate their organisational capabilities to achieve nimbleness and resilience during their digital transformation journey.
Originality/value
The relationship between dynamic capabilities and continuous digital transformation sheds light on establishing successful management processes within FSOs.
Details
Keywords
Zhufeng Yue, Ming Li, Lei Li and Zude Zhou
This paper aims to propose a new concept of product manufacturing mode which takes physical manufacturing theory as the basic starting point. In this work, the authors intend to…
Abstract
Purpose
This paper aims to propose a new concept of product manufacturing mode which takes physical manufacturing theory as the basic starting point. In this work, the authors intend to systematically define the basic connotation and extension of physical manufacturing, and sort out the typical characteristics of physical manufacturing, in order to propose the general concept of physical manufacturing.
Design/methodology/approach
How to study the combination of physics, mathematics, mechanics and other disciplines with the manufacturing disciplines, and how to elevate modern manufacturing science to a new height, has always been a problem for scientists in the field of manufacturing and engineering construction people to deeply think about. Therefore, on the basis of tracing the development of physics and combining the attributes and functions of manufacturing, the authors propose the basic concept of physical manufacturing. On this basis, the authors further clarify the connotation and extension, theoretical basis and technical system of physical manufacturing, reveal the basic problem domain of research and construct the theoretical foundation of physical manufacturing research, which are of great theoretical value and practical significance to adjust and optimize the manufacturing industry structure, improve the quality of manufacturing industry development and promote the green development of manufacturing industry.
Findings
The research on the basic theory and technical system of physical manufacturing will therefore broaden the way of thinking and make a better understanding of manufacturing science and technology, which will promote the development of manufacturing industry to some extent.
Originality/value
On the basis of continuous improvement of the basic theory and conceptual system of physical manufacturing, the physical manufacturing technology will become more and more perfect; physical manufacturing system and intelligent manufacturing system will become the mainstream of next-generation manufacturing system.
Details