AbstractTRIZ, also known as the theory of innovative problem-solving, has garnered attention from several proponents who advocate its merits as a systematic technique or toolkit that offers a rational framework for fostering creativity in pursuing innovation and creative problem-solving. The broad range of tools and procedures used in the TRIZ-based innovating enable the effective development of next-generation items while successfully enhancing existing ones. Using these tools and approaches may also facilitate the development of the necessary functionality and mitigate the costs associated with manufacturing processes, hence allowing the introduction of novel and enhanced products to be introduced into the market. This study aims to employ the TRIZ approach to develop an optimal laparoscopic chair design. The design of the laparoscopic chair was with a particular emphasis on ease and usability. The laparoscopic chair’s design demonstrated adherence to ergonomic principles despite the absence of actual ergonomic testing. This design has the chair’s adjustable components, which allow for height and level modifications, as well as customizable positioning to accommodate the preferences of the seated individual. The outcome of this design is comparable to laparoscopic chairs offered by medical corporations and preparing for the prototyping phase.
Abdelrahman Sakr, Ahmed Salih, Muhammed Hisham, Mohamed Elsherif, Andreas Schiffer, and Haider Butt
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Biosensors, colour vision deficiency, multifunctional contact lenses, tear pH sensing, neutral red dye, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTColour vision disorders, pose challenges in perceiving and distinguishing specific colours. To address these challenges, technologies such as colour-filtering glasses and contact lenses have been developed. However, customisation of eyewear for individual patients remains a challenge. This research aims to design multifunctional contact lenses combining colour filtering and pH sensing capabilities for personalised colour vision correction. A pH-responsive, Neutral red dye-doped hydrogel was developed and optimised for the vat photo polymerization-based 3D printing process. A novel in-house multimaterial 3D printing technique was employed for printing lenses exhibiting both colour filtering and pH sensing capabilities. 3D printed samples contained outer radial rings, made from porous and pH-responsive polymer. The optically tunable dye-doped resin was also applied to the central part of the lenses to achieve customised wavelength blockage. The lenses demonstrate potential for customised colour vision correction and pH monitoring of the tear film.
Abdulla Almesmari, Imad Barsoum, and Rashid K. Abu Al-Rub
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Lattice materials, topology optimization, additive manufacturing, energy absorption, metamaterials, testing, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTThis study investigates the mechanical behavior of a novel set of Cuboidal Spherical Plate Lattice (CSPL) materials. The procedure of constrained-domain topology optimization is implemented with the aim of enhancing stiffness. The micromechanical finite element homogenization approach is used to evaluate the effective elastic-plastic properties of the CSPLs and their topologically optimized counterparts, TOCSPLs (Topologically Optimized Cuboidal Spherical Plate Lattices). The TOCSPLs demonstrate higher uniaxial, shear, and bulk moduli compared to the CSPLs, with an increase of 31%, 14%, and 36% respectively. Moreover, there is an increase in the yield strengths under uniaxial, shear, and hydrostatic loading conditions, with enhancements of 103%, 55%, and 62%, respectively. The topologies are additively manufactured through Fused Deposition Modeling (FDM) out of ABS thermoplastic material. The quasi-static compression experiments demonstrate the superiority of TOCSPL 111+100 over the other topologies in terms of uniaxial modulus. The suffix 111+100 denotes the crystallographic planar orientations in which the solid plate-like disks were formed within a cubic system. The topologies proposed herein outperform certain types of Triply Periodic Minimal Surface, honeycomb, truss-, and plate-based lattice materials. The proposed topologies offer a compelling justification for their utilization in applications that require load-bearing and impact absorption capabilities.
Abdullah Alhijaily, Zekai Murat Kilic, and Paulo Bartolo
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Cooperative printing, concurrent printing, 3D printing, multi-robot additive manufacturing, path planning, collision avoidance, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTIt is well known that Additive Manufacturing (AM) is a slow process when compared to conventional manufacturing processes. To address this problem, this paper explores the concept of cooperative printing due to its ability to significantly increase the printing speed. It discusses current cooperative printing systems and proposes a new multi-arm configuration to address current limitations such as reduced cooperative printing area. The proposed configuration allows printing parts that are impossible to print or inefficiently printed by other configurations. Moreover, to improve efficiency and reduce printing time, new algorithms are proposed, including the Intermediate Point Method for collision avoidance. This method is three times more effective at preventing collisions compared to the current state-of-the-art algorithms and generates paths with lower travel durations. The proposed system was successfully tested in printing several single and multi-layer objects, showing a significant speed increase, surpassing the maximum printing time reduction reported in the literature.
Amit Bandyopadhyay, Aruntapan Dash, Lile Squires, Ethan Roberts, Jose D. Avila, Haley R. Doude, Ryan Stokes, Victor K. Champagne, and Susmita Bose
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Maraging steel grade 250 (M250), directed energy deposition-arc (DED-arc), wire arc DED (WA-DED), additive manufacturing (AM), 3D printing, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTMetal additive manufacturing is rapidly growing as a new paradigm in on-demand customised production, where high-performance bimetallic structures demand increasingly high-performance materials such as maraging steel grade 250 (M250). The behaviour of advanced materials in additively manufactured systems requires comprehensive understanding before it is possible to move beyond their use in simplistic monolithic designs. This study demonstrates the use of M250 in radial bimetallic near-net representative structures based on a comprehensive study of M250 in wire-arc additive depositions. Monolithic structures are first produced with minimal defects, confirmed by X-ray imaging. Phase, microstructure, and tensile properties are compared for heat-treated specimens and as-processed counterparts. EBSD and Charpy impact testing is performed, fracture morphology is compared, and microhardness is determined. Representative radial bimetallic structures are produced and similarly investigated, revealing anticipated microstructure. Our results demonstrate that a comprehensive understanding of advanced additive materials allows complete design flexibility.
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Stainless steel 316L (SS316L), 17-4PH, laser-directed energy deposition (L-DED), Additive manufacturing (AM), 3D Printing, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTBalancing strength and ductility is crucial for structural materials, yet often presents a paradoxical challenge. This research focuses on crafting a unique bimetallic structure, combining non-magnetic, stainless steel 316L (SS316L) with limited strength but enhanced ductility and magnetic, martensitic 17–4 PH with higher strength but lower ductility. Utilising a powder-based laser-directed energy deposition (L-DED) system, two vertical bimetallic configurations (SS316L/17-4 PH) and a radial bimetallic structure (SS316L core encased in 17–4 PH) were fabricated. Monolithic SS316L, 17–4 PH, and a 50% SS316L/50% 17–4 PH mixture were printed. The printed samples’ phase, microstructure, room temperature mechanical properties, and fracture morphology were examined in as-printed conditions. Bimetallic samples exhibited both phases, with a smooth grain transition at the interface. Radial bimetallic samples demonstrated higher mechanical strength than other compositions, except 17–4 PH. These findings showcase the potential of the L-DED approach for creating functional components with tailored mechanical properties.
ABSTRACTAdditive manufacturing in construction typically consists of ground-based platforms. Introducing aerial capabilities offers scope to create or repair structures in dangerous or elevated locations. The Aerial Additive Manufacturing (AAM) project has developed a pioneering approach using Unmanned Aerial Vehicles (UAV, ‘drones’) to deposit material during self-powered, autonomous, untethered flight. This study investigates high and low-density foams autonomously deposited as structural and insulation materials. Drilling resistance, mechanical, thermal and microscopy tests investigate density variation, interfacial integrity and thermal stability. Autonomous deposition is demonstrated using a flying UAV and robotic arm. Results reveal dense material at interfaces and directionally dependent cell expansion during foaming. Cured interfacial regions are vulnerable to loading parallel to interfaces but resistant to perpendicular loading. Mitigation of trajectory printing errors caused by UAV flight disturbance is demonstrated by a stabilising end effector, with trajectory errors ≤10 mm. AAM provides a significant development towards on-site automation in construction.HighlightsAerial Additive Manufacturing (AAM) releases additive manufacturing (AM) for construction applications from ground-based and tethered restraints.Multiple self-powered flying Unmanned Aerial Vehicles (UAV) can deposit layers of polyurethane foam in planned trajectories.High-density polyurethane foam and low-density foam can be suitable for structural and insulating layers, respectively.Laboratory tests, including drilling resistance, demonstrate the high-density of interfacial boundary regions in relation to material located away from a boundary.The challenges of reducing lateral deformation of extruded material are evaluated, and improved flight stabilisation provided by an end effector keeping trajectory errors within 10 mm is demonstrated.
Bo Yin, Meiguang Cao, Jin Huang, Long Shu, Hao Yi, Zhenhua Li, Liquan Jin, Chengheng Cai, and Changchang Yang
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Wire-arc additive manufacturing, droplet oscillation momentum, control strategy, molten pool fluctuation, surface-forming quality, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTIn feedback control systems of wire-arc additive manufacturing (WAAM), timely adjustments before the occurrence of deviations (feedforward control) would reduce excessive requirements on the sensitivity and accuracy of characteristic parameters of control systems. However, the search for characteristic parameters suitable for feedforward control is extremely rare in the WAAM field. Herein, based on ‘mass-spring' theory, a model of droplet oscillation momentum (DOM) is developed to describe the dynamic behavior of a pendant droplet and its influencing mechanism on surface roughness. The model combines the contribution of wire movement to droplet displacement with experimental correction of the spring/damping coefficients. The results show that the predictions of the model are in good agreement with the experimental values, and DOM is quadratically correlated with the surface roughness. Therefore, the model can be expected as a characteristic parameter to elucidate the development of surface-forming quality of WAAM-fabricated components.
Chaojiao Lei, Song Ren, Cunhong Yin, Xixia Liu, Mingfei Chen, Jiazhu Wu, and Changjun Han
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
Laser-based directed energy deposition, spatial laser intensity profile, thermofluidic transport, melt pool, numerical simulation, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTA three-dimensional thermofluidic coupling transport model is proposed to investigate the influences of different spatial laser intensity profiles (SLIPs), including circular super-Gaussian profile (C-SGP), transverse elliptical Gaussian profile (TE-GP) and longitudinal elliptical Gaussian profile (LE-GP), on the thermofluidic transport characteristics within the melt pool. The results demonstrate that the SLIPs dramatically influence the melt pool geometries, temperature gradient (both in magnitude and direction) at the solidification interface, and fluid flow dynamics. Under the TE-GP strategy, the highest average temperature gradients are observed at the solidification interface. The LE-GP strategy yields the smallest magnitudes and narrowest variation range of the temperature gradient direction angles. The heat transport of the melt pool under the C-SGP and TE-GP strategies are jointly dominated by convective and conductive heat transfer, while those under the LE-GP strategy are dominated by convective heat transfer. Marangoni convection is strongest in the LE-GP strategy and weakest in the TE-GP strategy.
Virtual and Physical Prototyping, Vol 19, Iss 1 (2024)
Subjects
3D printing, sub-microscale, electrodeposition, cold, metals, Science, Manufactures, and TS1-2301
Abstract
ABSTRACTLocally confined electrodeposition of precursors in liquid is one of the most effective approaches for additive manufacturing of metal microstructures. However, reported data were overwhelmingly obtained at the micrometer scale, whereas sub-microscale and nanoscale microstructures are of interest in electromagnetic or optical fields. In this paper, we propose a cold-constrained local electrodeposition (CCLE) technique to address the issue that locally confined electrodeposition of precursors in liquid is challenging in the fabrication of sub-microscale three-dimensional microstructures. Microstructure printing is conducted via locally confined electrodeposition by a pipette with a sub-microscale opening to deliver electrodeposition electrolyte in a supporting electrolyte. The electrolytes are cooled to 5 °C, which constrains the large-scale diffusion of the electrodeposition electrolyte and significantly reduces the electrodeposition area. It is found that the proposed CCLE technique can print sub-microscale (minimum size is low to 290 nm) structures, which have highly uniform deposits, smooth surfaces and high strength.