Self-Support Topology Optimization With Horizontal Overhangs for Additive Manufacturing

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Jikai Liu ◽  
Huangchao Yu
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Inclination Angle ◽  
The Self ◽  
New Method ◽  
Threshold Condition ◽  
Support Condition ◽  
Fused Deposition ◽  
Support Threshold ◽  
Overhang Length

Abstract Most of the existing self-support topology optimization methods restrict the overhang inclination angle to be larger than the self-support threshold value. However, for some additive manufacturing processes, such as fused deposition modeling, horizontal overhangs with zero inclination angle could be successfully printed while the overhang size plays a key role in determining the printability. Therefore, the self-support threshold condition should be re-developed to comprehensively consider the overhang size and inclination angle. At the same time, there raises the challenges of formulating the self-support constraints based on the new threshold condition. To address this difficulty, a novel method is proposed in this work to realize the design with horizontal overhangs. To be specific, the new method employs a skeleton-based structure decomposition approach to divide the structure into components based on the connectivity condition. Then, each component will be evaluated about its self-support status based on its overhang length and inclination angle. Finally, the self-support constraint will be activated only for those components that violate the threshold condition. An excellent feature of the method is that it can be adapted to address the only inclination angle self-support condition, or the comprehensive self-support condition that simultaneously considers the overhang length and inclination angle. Therefore, the new method serves for general applications to different additive manufacturing (AM) processes. Numerical examples will be studied to demonstrate the effectiveness of the proposed method.

scholarly journals Multi-solution nature of topology optimization and its application in design for additive manufacturing

2019 ◽  
Vol 25 (9) ◽  
pp. 1475-1481 ◽  
Author(s):  
Hassan Rezayat ◽  
Jared Richard Bell ◽  
Alex J. Plotkowski ◽  
Sudarsanam S. Babu
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Cantilever Beam ◽  
Mechanical Performance ◽  
Design Tool ◽  
Image Correlation ◽  
Content Type ◽  
Fused Deposition ◽  
Starting Point ◽  
Initial Starting

Purpose The purpose of this paper is to introduce the multi-solution nature of topology optimization (TO) as a design tool for additive manufacturing (AM). The sensitivity of topologically optimized parts and manufacturing constraints to the initial starting point of the optimization process leading to structures with equivalent performance is explored. Design/methodology/approach A modified bi-directional evolutionary structural optimization (BESO) code was used as the numerical approach to optimize a cantilever beam problem and reduce the mass by 50 per cent. Several optimized structures with relatively equivalent mechanical performance were generated by changing the initial starting point of the TO algorithm. These optimized structures were manufactured using fused deposition modeling (FDM). The equivalence of strain distribution in FDM parts was tested with the digital image correlation (DIC) technique and compared with that from the modified BESO code. Findings The results confirm that TO could lead to a wide variety of non-unique solutions based on loading and manufacturability constraints. The modified BESO code was able to reduce the support structure needed to build the simple two-dimensional cantilever beam by 15 per cent while keeping the mechanical performance at the same level. Originality/value The originality of this paper lies in introduction and application of the multi-solution nature of TO for AM as a design tool for optimizing structures with minimized features in the overhang condition and the need for support structures.

scholarly journals Innovative Joint for Cable Dome Structure Based on Topology Optimization and Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5158
Author(s):  
Wenfeng Du ◽  
Hui Wang ◽  
Liming Zhu ◽  
Yannan Zhao ◽  
Yingqi Wang ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Stress Distribution ◽  
Cast Steel ◽  
Utilization Rate ◽  
Integrated Manufacturing ◽  
Fused Deposition ◽  
Dome Structure ◽  
Cable Dome ◽  
Material Utilization

Aiming at the problems of a low material utilization rate and uneven stress distribution of cast-steel support joints in cable dome structures, topology optimization and additive manufacturing methods are used for optimization design and integrated manufacturing. First, the basic principle and calculation process of topology optimization are briefly introduced. Then, the initial model of the support joint is calculated and analyzed by using the universal software ANSYS Workbench 2020R2 and Altair OptiStruct, and the optimized joint is imported into Discovery Live to smooth the surface. The static behaviors of three types of joints (topology-optimized joints, joints after the smoothing treatment, and joints from practical engineering) are compared and analyzed. Finally, the joints are printed by using fused deposition modeling (FDM) technology and laser-based powder bed fusion (LBPBF) technology in additive manufacturing. The results show that the new support joint in the cable dome structure obtained by the topology optimization method has the advantages of a novel shape, a high material utilization rate, and a uniform stress distribution. Additive manufacturing technology can allow the manufacture of complex shape components with high precision and high speed. The combination of topology optimization and additive manufacturing effectively realizes the advanced design and integrated manufacturing of support joints for cable dome structures.

Additive manufacturing of an automotive brake pedal by metal fused deposition modelling

2021 ◽  
Author(s):  
M.I.M. Sargini ◽  
S.H. Masood ◽  
Suresh Palanisamy ◽  
Elammaran Jayamani ◽  
Ajay Kapoor
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modelling ◽  
Brake Pedal ◽  
Fused Deposition ◽  
Automotive Brake

scholarly journals 3D Printed Masks for Powders and Viruses Safety Protection Using Food Grade Polymers: Empirical Tests

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 617
Author(s):  
Ruben Foresti ◽  
Benedetta Ghezzi ◽  
Matteo Vettori ◽  
Lorenzo Bergonzi ◽  
Silvia Attolino ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Material Selection ◽  
Mechanical Resistance ◽  
Biological Safety ◽  
Fused Deposition ◽  
Industrial Grade ◽  
Safety Protection ◽  
3D Printed ◽  
Manufacturing Technologies

The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS-COV-2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet-based precision extrusion deposition (db-PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home-grade printing equipment have similar performances compared to the industrial-grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post-processing phases essential to assure human safety in the production of 3D printed custom medical devices.

scholarly journals A Shape Optimization Method for Part Design Derived from the Buildability Restrictions of the Directed Energy Deposition Additive Manufacturing Process

Designs ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 19
Author(s):  
Andreas K. Lianos ◽  
Harry Bikas ◽  
Panagiotis Stavropoulos
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Energy Deposition ◽  
Design Method ◽  
Current Trend ◽  
Internal Stresses ◽  
Material Distribution ◽  
Load Case ◽  
Design Elements ◽  
Industrial Sectors

The design methodologies and part shape algorithms for additive manufacturing (AM) are rapidly growing fields, proven to be of critical importance for the uptake of additive manufacturing of parts with enhanced performance in all major industrial sectors. The current trend for part design is a computationally driven approach where the parts are algorithmically morphed to meet the functional requirements with optimized performance in terms of material distribution. However, the manufacturability restrictions of AM processes are not considered at the primary design phases but at a later post-morphed stage of the part’s design. This paper proposes an AM design method to ensure: (1) optimized material distribution based on the load case and (2) the part’s manufacturability. The buildability restrictions from the direct energy deposition (DED) AM technology were used as input to the AM shaping algorithm to grant high AM manufacturability. The first step of this work was to define the term of AM manufacturability, its effect on AM production, and to propose a framework to estimate the quantified value of AM manufacturability for the given part design. Moreover, an AM design method is proposed, based on the developed internal stresses of the build volume for the load case. Stress tensors are used for the determination of the build orientation and as input for the part morphing. A top-down mesoscale geometric optimization is used to realize the AM part design. The DED Design for Additive Manufacturing (DfAM) rules are used to delimitate the morphing of the part, representing at the same time the freeform mindset of the AM technology. The morphed shape of the part is optimized in terms of topology and AM manufacturability. The topology optimization and AM manufacturability indicator (TMI) is introduced to screen the percentage of design elements that serve topology optimization and the ones that serve AM manufacturability. In the end, a case study for proof of concept is realized.

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