scholarly journals An Open Source Framework for Integrated Additive Manufacturing and Level-Set-Based Topology Optimization

Author(s):  
Panagiotis Vogiatzis ◽  
Shikui Chen ◽  
Chi Zhou

Topology optimization has been considered as a promising tool for conceptual design due to its capability of generating innovative design candidates without depending on the designer's intuition and experience. Various optimization methods have been developed through the years, and one of the promising options is the level-set-based topology optimization method. The benefit of this alternative method is that the design is characterized by its clear boundaries. This advantage can avoid postprocessing work in conventional topology optimization process to a large extent and realize direct integration between topology optimization and additive manufacturing (AM). In this paper, practical algorithms and a matlab-based open source framework are developed to seamlessly integrate the level-set-based topology optimization procedure with AM process by converting the design to STereoLithography (STL) files, which is the de facto standard format for three-dimensional (3D) printing. The proposed algorithm and code are evaluated by a proof-of-concept demonstration with 3D printing of both single and multimaterial topology optimization results. The algorithm and the open source framework proposed in this paper will be beneficial to the areas of computational design and AM.

Author(s):  
Panagiotis Vogiatzis ◽  
Ming Ma ◽  
Shikui Chen ◽  
Xianfeng David Gu

In this paper, we present a computational framework for computational design and additive manufacturing of spatial free-form periodic metasurfaces. The proposed scheme rests on the level-set based topology approach and the conformal mapping theory. A 2D unit cell of metamaterial with tailored effective properties is created using the level-set based topology optimization method. The achieved unit cell is further mapped to the 3D quad meshes on a free-form surface by applying the conformal mapping method which can preserve the local shape and angle when mapping the 2D design to a 3D surface. The proposed level-set based optimization methods not only can act as a motivator for design synthesis, but also can be seamlessly hooked with additive manufacturing with no need of CAD reconstructions. The proposed computational framework provides a solution to increasing applications involving innovative metamaterial designs on free-form surfaces in different fields of interest. The performance of the proposed scheme is illustrated through a benchmark example where a negative-Poisson’s-ratio unit cell pattern is mapped to a 3D human face and fabricated through additive manufacturing.


Author(s):  
Panagiotis Vogiatzis ◽  
Shikui Chen ◽  
Chi Zhou

Since topology optimization has become an important part of the design procedure, various optimization methods have been developed through the years. One of the promising options is the use of level-set based topology optimization method. In this method, the design is the zero level of a one higher dimension level-set function Φ. The benefit of this alternative method is that the final design is characterized by its clear boundaries. This advantage is based on the fact that post-processing work is not needed on the final design and it can be directly sent to the manufacturing line. The designers, in order to visualize their innovative results, often build prototypes using 3D printers, given that the designs may have complicated features. Furthermore, cost permitting, 3D printing can also be considered for mass customization. Either way, the result of the optimization has to be translated to a file that 3D printers can recognize. In this paper, the authors have developed a MATLAB code that can be integrated in the topology optimization procedure and convert the design to an STL file (STereoLithography), which is the de facto format for 3D printing.


2021 ◽  
Vol 11 (13) ◽  
pp. 6086
Author(s):  
Nils Ellendt ◽  
Fabian Fabricius ◽  
Anastasiya Toenjes

Additive manufacturing processes offer high geometric flexibility and allow the use of new alloy concepts due to high cooling rates. For each new material, parameter studies have to be performed to find process parameters that minimize microstructural defects such as pores or cracks. In this paper, we present a system developed in Python for accelerated image analysis of optical microscopy images. Batch processing can be used to quickly analyze large image sets with respect to pore size distribution, defect type, contribution of defect type to total porosity, and shape accuracy of printed samples. The open-source software is independent of the microscope used and is freely available for use. This framework allows us to perform such an analysis on a circular area with a diameter of 5 mm within 10 s, allowing detailed process maps to be obtained for new materials within minutes after preparation.


2019 ◽  
Vol 14 (1) ◽  
pp. 111-124
Author(s):  
Roberto Naboni ◽  
Anja Kunic

Overconsumption of resources is one of the greatest challenges of our century. The amount of material that is being extracted, harvested and consumed in the last decades is increasing tremendously. Building with new manufacturing technology, such as 3D Printing, is offering new perspectives in the way material is utilized sustainably within a construction. This paper describes a study on how to use Additive Manufacturing to support design logics inspired by the bone microstructure, in order to build materially efficient architecture. A process which entangles computational design methods, testing of 3D printed specimens, developments of prototypes is described. A cellular-based tectonic system with the capacity to vary and adapt to different loading conditions is presented as a viable approach to a material-efficient construction with Additive Manufacturing.


2013 ◽  
Vol 5 (2) ◽  
pp. 194-201
Author(s):  
Michael Hansmeyer ◽  
Benjamin Dillenburger

Computational design allows for architecture with an extraordinary degree of topographical and topological complexity. Limitations of traditional CNC technologies have until recently precluded this architecture from being fabricated. While additive manufacturing has made it possible to materialize these complex forms, this has occurred only at a very small scale. In trying to apply additive manufacturing to the construction of full-scale architecture, one encounters a dilemma: existing large-scale 3D printing methods can only print highly simplified shapes with rough details, while existing high-resolution technologies have limited print spaces, high costs, or material attributes that preclude a structural use. This paper provides a brief background on additive manufacturing technology and presents recent developments in sand-printing technology that overcome current 3D printing restrictions. It then presents a specific experiment, Digital Grotesque project, which is the first application of 3D sand-printing technology at an architecture scale. It describes how this project attempts to exploit the potentials of these new technologies.


2021 ◽  
Vol 11 (4) ◽  
pp. 1437
Author(s):  
Evangelos Tyflopoulos ◽  
Mathias Lien ◽  
Martin Steinert

The weight optimization of a structure can be conducted by using fewer and downsized components, applying lighter materials in production, and removing unwanted material. Topology optimization (TO) is one of the most implemented material removal processes. In addition, when it is oriented towards additive manufacturing (AM), it increases design flexibility. The traditional optimization approach is the compliance optimization, where the material layout of a structure is optimized by minimizing its overall compliance. However, TO, in its current state of the art, is mainly used for design inspiration and not for manufacturing due to design complexities and lack of accuracy of its design solutions. The authors, in this research paper, explore the benefits and the limitations of the TO using as a case study the housings of a front and a rear brake caliper. The calipers were optimized for weight reduction by implementing the aforementioned optimization procedure. Their housings were topologically optimized, partially redesigned, prepared for 3D printing, validated, and 3D printed in titanium using selective laser melting (SLM). The weight of the optimized calipers reduced by 41.6% compared to commercial calipers. Designers interested in either TO or in automotive engineering can exploit the findings in this paper.


Author(s):  
Eric MacDonald ◽  
Edward Burden ◽  
Jason Walker ◽  
Jonathan Kelly ◽  
Brett Conner ◽  
...  

Process control in 3D printing (also known formally as Additive Manufacturing - AM) has largely been absent even in production systems. Simultaneously, computer vision has become more accessible with open source libraries (e.g. OpenCV, used successfully for traversing the state of California in an autonomous vehicle to win a DARPA Grand Challenge). 3D printing is particularly well suited to be enhanced by computer vision as fabrication is layer wise and predictable assuming correct operation. Big Area Additive Manufacturing (BAAM) — operating at significantly larger scales than traditional 3D printing — stands to benefit given the higher throughput of material (hundreds of pounds per hour) and the associated high costs of errant fabrication. Furthermore, minimum feature sizes in BAAM, such as individual layers, are sufficiently large to be analyzed with standard photography. With computer vision, sophisticated algorithms can be applied to identify problems early in the process that are not normally manifest until after process completion. Subtle and latent defects can be remediated before the onset of permanent damage or at a minimum the process can be aborted to avoid significant material loss. Fourier analysis can provide a useful perspective of the spatial periodicity of the layers of exposed surfaces during fabrication and this spectral information can inform the process of surface roughness, delamination, and deposition consistency in a data efficient manner. The large layer thickness of BAAM allow for Fourier analysis to be performed with standard photography. This paper explores the implementation and advantages of a low cost computer vision system that leverages OpenCV libraries operating on a Raspberry Pi Linux computer with simple yet high resolution photography — driven by the hypothesis that quality and yield of open source BAAM hardware can be dramatically enhanced.


Author(s):  
Long Jiang ◽  
Hang Ye ◽  
Chi Zhou ◽  
Shikui Chen

The significant advance in the boosted fabrication speed and printing resolution of additive manufacturing (AM) technology has considerably increased the capability of achieving product designs with high geometric complexity and provided tremendous potential for mass customization. However, it is also because of geometric complexity and large quantity of mass-customized products that the prefabrication (layer slicing, path planning, and support generation) is becoming the bottleneck of the AM process due to the ever-increasing computational cost. In this paper, the authors devise an integrated computational framework by synthesizing the parametric level set-based topology optimization method with the stereolithography (SLA)-based AM process for intelligent design and manufacturing of multiscale structures. The topology of the design is optimized with a distance-regularized parametric level set method considering the prefabrication computation. With the proposed framework, the structural topology optimization not only can create single material structure designs but also can generate multiscale, multimaterial structures, offering the flexibility and robustness of the structural design that the conventional methods could not provide. The output of the framework is a set of mask images that can be directly used in the AM process. The proposed approach seamlessly integrates the rational design and manufacturing to reduce the numerical complexity of the computationally expensive prefabrication process. More specifically, the prefabrication-friendly design and optimization procedure are devised to drastically eliminate the redundant computations in the traditional framework. Two test examples, including a free-form 3D cantilever beam and a multiscale meta-structure, are utilized to demonstrate the performance of the proposed approach. Both the simulation and experimental results verified that the new rational design could significantly reduce the prefabrication computation cost without affecting the original design intent or sacrificing the original functionality.


Author(s):  
N. Dresler ◽  
A. Ulanov ◽  
M. Aviv ◽  
D. Ashkenazi ◽  
A. Stern

The 4D additive manufacturing processes are considered today as the "next big thing" in R&D. The aim of this research is to provide two examples of commercial PLA based shape memory polymer (SMP) objects printed on an open-source 3D printer in order to proof the feasibility of such novel 4D printing process. To that purpose, a PLA based filament of eSUN (4D filament e4D-1white, SMP) was chosen, and two applications, a spring and a vase, were designed by 3D-printing with additive manufacturing (AM) fused filament fabrication (FFF) technique. The 4D-printed objects were successfully produced, the shape memory effect and their functionality were demonstrated by achieving the shape-memory cycle of programming, storage and recovery.


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