Design of injection nozzle in direct metal deposition (DMD) manufacturing of thin-walled structures based on 3D models

2016 ◽  
Vol 91 (1-4) ◽  
pp. 605-616 ◽  
Author(s):  
Jingyuan Yan ◽  
Ilenia Battiato ◽  
Georges Fadel
Keyword(s):  
3D Models ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Injection Nozzle ◽  
Thin Walled Structures ◽  
Thin Walled

Design of Injection Nozzle in Direct Metal Deposition (DMD) Manufacturing of Thin-Walled Structures Based on 3D Models

2016 ◽  
Author(s):  
Jingyuan Yan ◽  
Ilenia Battiato ◽  
Georges Fadel
Keyword(s):  
Laser Energy ◽  
3D Models ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Injection Nozzle ◽  
Thin Walled Structures ◽  
Nozzle Shape ◽  
Thin Walled ◽  
Manufacturing Techniques ◽  
Optimization Methodology

The Direct Metal Deposition (DMD) process is one of the most important metal based additive manufacturing techniques available today. In this study, a print head design optimization methodology is proposed based on the finite element modeling of powder distribution and substrate temperature distribution. The design methodology is applied to the deposition of Ti-6Al-4V powder in building thin-walled (≈ 0.7 mm) structures, which is also applicable to solid parts. The design objective is to find the optimal design of the injection nozzle shape that can maximize the powder usage and minimize laser energy needs, later defined as powder and laser energy efficiencies. A neural network is built to investigate the nozzle shape parameters based on the results from the 3D powder flow model. With the methodology proposed in this study, the optimal injection nozzle design can be found.

Laser direct metal deposition process of thin-walled parts using variable spot by inside-beam powder feeding

2018 ◽  
Vol 24 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Lifang Wang ◽  
Gangxian Zhu ◽  
Tuo Shi ◽  
Jizhuo Wu ◽  
Bin Lu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Laser Spot ◽  
Layer By Layer ◽  
Single Track ◽  
Content Type ◽  
Practical Applications ◽  
Thin Walled ◽  
Powder Feeding

Purpose The purpose of this paper is to improve the forming efficiency and quality of unequal-width parts fabricated by laser direct metal deposition technology, some experiments were designed. Design/methodology/approach A new method by varying laser spot was adopted to fabricate unequal-width single track using one scanning rather than multi-track overlapping in the way of the inside-beam powder feeding, and the thin-walled parts were fabricated layer by layer. The theoretical model among layer thickness of z-axis, height of single track and the section curve order of single track was established. Findings The top surface unevenness of the thin-walled parts could be compensated automatically within the laser defocusing ranges from −2.5 to −5 mm and from 0.5 to 2.5 mm. The growth rate with the large width/height ratio was more than the small ratio, while the set height of the single track was uniform. The problem of non-uniform growth rate could be solved based on a stepped single-track method. The thin-walled parts with the smooth top surface was fabricated layer by layer which had a continuously variable width from 1 to 3 mm by splicing the laser defocusing range. Practical implications The shapes of the to-be-fabricated parts affect variable laser spot process in practical applications. For example, it will be difficult to apply variable laser spot process on the parts with the hole features. Originality/value This paper provided a guidance for forming unequal-width parts by laser direct metal deposition based on the inside-beam powder feeding.

Frame-Monolithic Technology of Construction of Low-Rise Buildings Made of Foam Gypsum and Steel Thin-Walled Structures

2018 ◽  
Vol 762 (8) ◽  
pp. 36-39 ◽  
Author(s):  
B.G. BULATOV ◽  
◽  
R.I. SHIGAPOV ◽  
M.A. IVLEV ◽  
I.V. NEDOSEKO ◽  
...  
Keyword(s):  
Thin Walled Structures ◽  
Thin Walled

Significance of continuous wave and pulsed wave laser in direct metal deposition

2021 ◽  
Author(s):  
S. Pratheesh Kumar ◽  
S. Elangovan ◽  
R. Mohanraj ◽  
V. Sathya Narayanan
Keyword(s):  
Continuous Wave ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Wave Laser

scholarly journals Fracture Mechanical Analysis of Thin-Walled Cylindrical Shells with Cracks

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 592
Author(s):  
Feng Yue ◽  
Ziyan Wu
Keyword(s):  
Fracture Mechanics ◽  
Tensile Stress ◽  
Failure Modes ◽  
Cylindrical Shells ◽  
Crack Tip ◽  
Mechanical Analysis ◽  
J Integral ◽  
Thin Walled Structures ◽  
Circumferential Tensile Stress ◽  
Thin Walled

The fracture mechanical behaviour of thin-walled structures with cracks is highly significant for structural strength design, safety and reliability analysis, and defect evaluation. In this study, the effects of various factors on the fracture parameters, crack initiation angles and plastic zones of thin-walled cylindrical shells with cracks are investigated. First, based on the J-integral and displacement extrapolation methods, the stress intensity factors of thin-walled cylindrical shells with circumferential cracks and compound cracks are studied using linear elastic fracture mechanics, respectively. Second, based on the theory of maximum circumferential tensile stress of compound cracks, the number of singular elements at a crack tip is varied to determine the node of the element corresponding to the maximum circumferential tensile stress, and the initiation angle for a compound crack is predicted. Third, based on the J-integral theory, the size of the plastic zone and J-integral of a thin-walled cylindrical shell with a circumferential crack are analysed, using elastic-plastic fracture mechanics. The results show that the stress in front of a crack tip does not increase after reaching the yield strength and enters the stage of plastic development, and the predicted initiation angle of an oblique crack mainly depends on its original inclination angle. The conclusions have theoretical and engineering significance for the selection of the fracture criteria and determination of the failure modes of thin-walled structures with cracks.

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