3-D Printed Protective Equipment during COVID-19 Pandemic

While the number of coronavirus cases from 2019 continues to grow, hospitals are reporting shortages of personal protective equipment (PPE) for frontline healthcare workers. Furthermore, PPE for the eyes and mouth, such as face shields, allow for additional protection when working with aerosols. 3-D printing enables the easy and rapid production of lightweight plastic frameworks based on open-source data. The practicality and clinical suitability of four face shields printed using a fused deposition modeling printer were examined. The weight, printing time, and required tools for assembly were evaluated. To assess the clinical suitability, each face shield was worn for one hour by 10 clinicians and rated using a visual analogue scale. The filament weight (21-42 g) and printing time (1:40-3:17 h) differed significantly between the four frames. Likewise, the fit, wearing comfort, space for additional PPE, and protection varied between the designs. For clinical suitability, a chosen design should allow sufficient space for goggles and N95 respirators as well as maximum coverage of the facial area. Consequently, two datasets are recommended. For the final selection of the ideal dataset to be used for printing, scalability and economic efficiency need to be carefully balanced with an acceptable degree of protection

A level set based method for fixing overhangs in 3D printing

3D printers based on the Fused Decomposition Modeling create objects layer-by-layer dropping fused material. As a consequence, strong overhangs cannot be printed because the new-come material does not find a suitable support over the last deposed layer. In these cases, one can add some support structures (scaffolds) which make the object printable, to be removed at the end. In this paper we propose a level set method to create object-dependent support structures, specifically conceived to reduce both the amount of additional material and the printing time. We also review some open problems about 3D printing which can be of interests for the mathematical community

From 3D Models to 3D Prints: an Overview of the Processing Pipeline

Due to the wide diffusion of 3D printing technologies, geometric algorithms for Additive Manufacturing are being invented at an impressive speed. Each single step, in particular along the Process Planning pipeline, can now count on dozens of methods that prepare the 3D model for fabrication, while analysing and optimizing geometry and machine instructions for various objectives. This report provides a classification of this huge state of the art, and elicits the relation between each single algorithm and a list of desirable objectives during Process Planning. The objectives themselves are listed and discussed, along with possible needs for tradeoffs. Additive Manufacturing technologies are broadly categorized to explicitly relate classes of devices and supported features. Finally, this report offers an analysis of the state of the art while discussing open and challenging problems from both an academic and an industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and Innovation action; Grant agreement N. 68044

Towards Zero-Waste Furniture Design

In traditional design, shapes are first conceived, and then fabricated. While this decoupling simplifies the design process, it can result in inefficient material usage, especially where off-cut pieces are hard to reuse. The designer, in absence of explicit feedback on material usage remains helpless to effectively adapt the design -- even though design variabilities exist. In this paper, we investigate {\em waste minimizing furniture design} wherein based on the current design, the user is presented with design variations that result in more effective usage of materials. Technically, we dynamically analyze material space layout to determine {\em which} parts to change and {\em how}, while maintaining original design intent specified in the form of design constraints. We evaluate the approach on simple and complex furniture design scenarios, and demonstrate effective material usage that is difficult, if not impossible, to achieve without computational support

Additive Manufacturing for Nautical Design An Automated Approach to Marine Manufacturing

How can additive manufacturing (AM) technology be applied to automate the production of small marine vessels? For the past 50 years small (below 40 meters) marine vessel manufacturing has been dominated by moulded fiber-reinforced plastics (FRP). There are several shortcomings to this manufacturing method that affect both the formal outcome and the manufacturing process of boats built in FRP: 1) manufacturing requires the use of expensive moulds, 2) formal geometric freedom is limited by moulds which reduce the potential for customization, and 3) special assemblies and structural reinforcements must be moulded separately and joined using a time-consuming hand lay-up process. The use of AM may reduce cost of production by eliminating need for moulds, allow greater ease of customization, and improve worker safety by limiting exposure to harmful materials and chemicals. The purpose of this research project is to evaluate existing AM technology and assess its potential for application to small marine vessel manufacturing. The project aims to investigate new methods for generating novel AM tool paths and demonstrate through proof of concept that it may be possible to produce the complex topological surfaces and assemblies that are common in marine vessels using multi-bias additive manufacturing (MBAM). However, AM is a broad term that describes a variety of different ways to manufacture objects. As such, AM can be applied to marine manufacturing in a variety of different ways, in different phases of the manufacturing process, and to different extents. At the same time, building boats is a complex process that presents specific problems that must be addressed in any automation solution. Several marine vessel construction projects have already been completed using AM which can serve as case studies for understanding the opportunities and challenges for applying AM to the marine sector. A review of the current state of the technology and qualitative analysis (QA) of case studies provides a set of guidelines for designing a manufacturing method that may prove effective for producing small marine vessels using AM. The project relied on design-based research (DBR) to develop a series of experimental extruder prototypes for novel toolpath testing on excerpts from a small reference vessel. The combination of QA and DBR experimentation point to a manufacturing solution using articulated robotic manipulators and a continuous fiber thermoset plastic extruder using a modified version of the fused filament fabrication process. This kinematic solution can be extended with external linear or rotational axes and/or by mounting robotic manipulators within a large gantry. This will allow the extruder to approach the work using a wide range of orientations that will be optimal for both the geometry of marine vessels and the requirements of MBAM extrusion. Meanwhile, toolpath generation using the software Grasshopper with KukaPRC plugin demonstrated a proof of concept for creating MBAM toolpaths optimized for small marine vessels. While the method proved feasible for smaller excerpts there remain significant challenges to successful deployment of this manufacturing method that can only be addressed with additional research