The COVID-19 pandemic significantly increased demand for medical and protective equipment by frontline health workers, as well as the general community, causing the supply chain to stretch beyond capacity, an issue further heightened by geographical and political lockdowns. Various 3D printing technologies were quickly utilised by businesses, institutions and individuals to manufacture a range of products on-demand, close to where they were needed. This study gathered data about 91 3D printed projects initiated prior to April 1, 2020, as the virus spread globally. It found that 60% of products were for personal protective equipment, of which 62% were 3D printed face shields. Fused filament fabrication was the most common 3D print technology used, and websites were the most popular means of centralising project information. The project data provides objective, quantitative insight balanced with qualitative critical review of the broad trends, opportunities and challenges that could be used by governments, health and medical bodies, manufacturing organisations and the 3D printing community to streamline the current response, as well as plan for future crises using a distributed, flexible manufacturing approach.

In the past decade, 3D printing technologies have been adopted for the fabrication of microfluidic devices. Extrusionbased approaches including fused filament fabrication (FFF), jetting technologies including inkjet 3D printing, and vat photopolymerization techniques including stereolithography (SLA) and digital light projection (DLP) are the 3D printing methods most frequently adopted by the microfluidic community. Each printing technique has merits toward the fabrication of microfluidic devices. Inkjet printing offers a good selection of materials and multimaterial printing, and the large build space provides manufacturing throughput, while FFF offers a great selection of materials and multimaterial printing but at lower throughput compared to inkjet 3D printing. Technical and material developments adopted from adjacent research fields and developed by the microfluidic community underpin the printing of sub-100 μm enclosed microchannels by DLP, but challenges remain in multimaterial printing throughput. With the feasibility of 3D printed microfluidics established, we look ahead at trends in 3D printing to gain insights toward the future of this technology beyond the sole prism of being an alternative fabrication approach. A shift in emphasis from using 3D printing for prototyping, to mimic conventionally manufactured outputs, toward integrated approaches from a design perspective is critically developed.

No abstract

In response to shortages in personal protective equipment (PPE) during the COVID-19 pandemic, makers, community groups and manufacturers around the world utilised 3D printing to fabricate items, including face shields and face masks for healthcare workers and the broader community. In reaction to both local and global needs, numerous designs emerged and were shared online. In this paper, 37 face shields and 31 face masks suitable for fused filament fabrication were analysed from a fabrication perspective, documenting factors such as filament use, time to print and geometric qualities. 3D print times for similar designs varied by several hours, meaning some designs could be produced in higher volumes. Overall, the results show that face shields were approximately twice as fast to 3D print compared to face masks and used approximately half as much filament. Additionally, a face shield typically required 1.5 parts to be 3D printed, whereas face masks required 5 3D printed parts. However, by quantifying the print times, filament use, 3D printing costs, part dimensions, number of parts and total volume of each design, the wide variations within each product category could be tracked and evaluated. This data and objective analysis will help makers, manufacturers, regulatory bodies and researchers consolidate the 3D printing response to COVID-19 and optimise the ongoing strategy to combat supply chain shortages now and in future healthcare crises.

3D printing provides new opportunities to create devices used during radiotherapy treatments, yet little is known about the effect process parameters play on the proposed devices. This study investigates the combined influence of infill pattern, infill density and print orientation on surface dose, as well as on the mechanical properties of 3D printed samples, identifying the optimal infill patterns for use in radiotherapy devices including immobilisation. Fused deposition modelling (FDM) was used to produce sixty samples in two orientations for surface dose measurement, utilising ten different infill patterns. Surface dose testing was performed using a Varian Trubeam linear accelerator with a 6 MV photon beam. A further one hundred and twenty tensile test samples, designed according to ASTM D638 type I standards, were evaluated using a 50 KN Instron 5969. On average, horizontally printed samples had a lower surface dose measurement compared to the vertically orientated samples, with the Stars infill pattern recording the lowest surface dose values in the horizontal orientation, while the Hilbert Curve recorded the lowest surface dose in the edge orientation. Tensile tests revealed the 3D Honeycomb infill pattern to have the highest ultimate tensile strength (UTS) in both horizontal and edge orientations. Overall, the Stars infill pattern exhibited the optimal balance of low surface dose and above average UTS. This study shows how infill patterns can significantly affect dosimetry and mechanical performance of 3D printed radiotherapy devices, and the data can be used by design engineers, clinicians and medical physicists to select the appropriate infill pattern, density and print orientation based on the functional requirements of a radiotherapy device.

No abstract

Within the sport of cycling, aerodynamic efficiency is a fundamental criterion for equipment such as bicycle frames, wheels, clothing and helmets. Emerging technologies continually challenge the rules governing the sport, as designers, engineers, sports scientists and athletes attempt to gain the edge on their competition. This study compares the aerodynamic drag force of three 3D-printed bicycle helmet prototypes with three commercially available helmets via aerodynamic testing in a wind tunnel. One 3D printed helmet featured a mechanical mechanism, allowing two states of ventilation to be examined for aerodynamic efficiency, while another featured electronically adjustable ventilation tested at five different states of ventilation opening. A third 3D printed helmet acted as a control, based on a budget-level helmet design. Data was collected using an anthropometrically accurate mannequin sitting atop a bicycle in a road cycling position. The results found that the mechanically controlled prototype offered a 4.1% increase in overall drag experienced by the mannequin with ventilation in the open position compared to the closed position. The electronic prototype showed an increase in drag as ventilation opening increased through the five states, with an overall difference in drag of 3.7% between closed and the maximum opening. These experimental findings indicate the significant effect that helmet ventilation design can play on the drag forces experienced by a cyclist. This may provide new opportunities to modify athlete performance throughout varying stages of training and competition using sensors and autonomous control systems.

Purpose This paper aims to present new qualitative and quantitative data about the recently released “BigRep ONE” 3 D printer led by the design of a one-off customized stool. Design/methodology/approach A design for additive manufacturing (DfAM) framework was adopted, with simulation data iteratively informing the final design. Findings Process parameters can vary manufacturing costs of a stool by over AU$1,000 and vary print time by over 100 h. Following simulation, designers can use the knowledge to inform iteration, with a second variation of the design being approximately 50 per cent cheaper and approximately 50 per cent faster to manufacture. Metrology data reveal a tolerance = 0.342 per cent in overall dimensions, and surface roughness data are presented for a 0.5 mm layer height. Research limitations/implications Led by design, this study did not seek to explore the full gamut of settings available in slicing software, focusing predominantly on nozzle diameter, layer height and number of walls alongside the recommended settings from BigRep. The study reveals numerous areas for future research, including more technical studies. Practical implications When knowledge and techniques from desktop 3 D printing are scaled up to dimensions measuring in meters, new opportunities and challenges are presented for design engineers. Print times and material costs in particular are scaled up significantly, and this study provides numerous considerations for research centers, 3 D printing bureaus and manufacturers considering large-scale fused filament fabrication manufacturing. Originality/value This is the first peer-reviewed study involving the BigRep ONE, and new knowledge is presented about the practical application of the printer through a design-led project. Important relationships between material volume/cost and print time are valuable for early adopters.