Anwendung einer hauptnormalspannungs-orientierten Füllstrategie für Fused Layer Manufacturing Strukturen

2021 ◽  
Vol 1 ◽  
pp. 63-86
Author(s):  
Alexander Kißling
Keyword(s):  
Author(s):  
Chao-Yaug Liao ◽  
Jean-Claude Léon ◽  
Cédric Masclet ◽  
Michel Bouriau ◽  
Patrice L. Baldeck ◽  
...  

Based on the two-photon polymerization technique, an analysis of product shapes is performed so that their digital manufacturing models can be efficiently processed for micromanufacture. To describe microstructures, this analysis shows that nonmanifold models are of interest. These models can be intuitively understood as combinations of wires, surfaces, and volumes. Minimum acceptable wall thickness, wire dimension, and laser density of energy are among the elements justifying this category of models. Taking into account this requirement, a model preparation and processing scheme is proposed that widens the laser beam trajectories with a concept of extended layer manufacturing technique. A tessellation process suited for non-manifold models has been developed for computer-aided design models imported from standard for the exchange of product files. After tessellation, several polyhedral subdomains form a nonmanifold polyhedron. To plan the trajectories of the laser beam, adaptive slicing and global 3D hatching processes as well as a “welding” process (for joining subdomains of different dimensionality) have been combined. Finally, two nonmanifold microstructures are fabricated according to the proposed model preparation and processing scheme.


2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Ercan M. Dede ◽  
Shailesh N. Joshi ◽  
Feng Zhou

Topology optimization of an air-cooled heat sink considering heat conduction plus side-surface convection is presented. The optimization formulation is explained along with multiple design examples. A postprocessing procedure is described to synthesize manifold or “water-tight” solid model computer-aided design (CAD) geometry from three-dimensional (3D) point-cloud data extracted from the optimization result. Using this process, a heat sink is optimized for confined jet impingement air cooling. A prototype structure is fabricated out of AlSi12 using additive layer manufacturing (ALM). The heat transfer and fluid flow performance of the optimized heat sink are experimentally evaluated, and the results are compared with benchmark plate and pin-fin heat sink geometries that are conventionally machined out of aluminum and copper. In two separate test cases, the experimental results indicate that the optimized ALM heat sink design has a higher coefficient of performance (COP) relative to the benchmark heat sink designs.


Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 161
Author(s):  
Miranda Fateri ◽  
João Falcão Carneiro ◽  
Achim Frick ◽  
João Bravo Pinto ◽  
Fernando Gomes de Almeida

In this paper, endurance of peristaltic linear pneumatic actuators was studied using different hose geometries. Towards this goal, different hose geometries were additively manufactured using Fused Layer Manufacturing techniques of Thermoplastic Polyurethane Elastomer. Material properties of the elastomer were studied using Differential Scanning Calorimetry and the tensile test. The relations between the sample’s print temperature and build direction on the actuator endurance were investigated. Lastly, the relation between the geometry design of the PLPA actuator and its endurance is also discussed. Based on this methodology, authors present results showing that the use of a customized shaped hose with geometrical reinforcement at sides leads to a considerable rise in the hose endurance, when compared with the conventional circular design.


2021 ◽  
Author(s):  
Carlo Bruni ◽  
Luciano Greco ◽  
Tommaso Mancia ◽  
Massimiliano Pieralisi

The additive manufacturing technique represents a way to realize components or prototypes without the use of conventional tools.The research presented aims at proposing a methodology based on the use of three different techniques that are the poly-jet 3D using UV photo-polymerization, the FDM of polyamide materials and the FDM of PLA materials. The original data were used at the beginning with the first technique in order to detect the shape and the geometry by a 3D SCANNER. The objective was the re-building of a model shape made using a procedure in which the input file characteristics were updated starting from those got by the scanning device in order to respect the original requirements defined in the computer aided environment. It was found that the physical re-building of an object is depending the characteristics of the input file that needs to be digitally processed in order to get the desired shape and geometry. In that way also FDM using PLA and polyamide materials can be utilized to get components or prototypes from scanned digital data. The results are reported in details.


Author(s):  
Sagar H. Nikam ◽  
N. K. Jain

Prediction of residual stresses induced by any additive layer manufacturing process greatly helps in preventing thermal cracking and distortion formed in the substrate and deposition material. This paper presents the development of a model for the prediction of residual stresses using three-dimensional finite element simulation (3D-FES) and their experimental validation in a single-track and double-track deposition of Ti-6Al-4V powder on AISI 4130 substrate by the microplasma transferred arc (µ-PTA) powder deposition process. It involved 3D-FES of the temperature distribution and thermal cycles that were validated experimentally using three K-type thermocouples mounted along the deposition direction. Temperature distribution, thermal cycles, and residual stresses are predicted in terms of the µ-PTA process parameters and temperature-dependent properties of substrate and deposition materials. Influence of a number of deposition tracks on the residual stresses is also studied. Results reveal that (i) tensile residual stress is higher at the bonding between the deposition and substrate and attains a minimum value at the midpoint of a deposition track; (ii) maximum tensile residual stress occurs in the substrate material at its interface with deposition track. This primarily causes distortion and thermal cracks; (iii) maximum compressive residual stress occurs approximately at mid-height of the substrate material; and (iv) deposition of a subsequent track relieves tensile residual stress induced by the previously deposited track.


Procedia CIRP ◽  
2020 ◽  
Vol 93 ◽  
pp. 38-43
Author(s):  
Nico Helfesrieder ◽  
Armin Lechler ◽  
Alexander Verl

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