Heat transfer and material flow during laser assisted multi-layer additive manufacturing

The increased design space offered by additive manufacturing can inspire unique ideas and different modeling approaches. One tool for generating complex yet effective designs is found in numerical optimization schemes, but until relatively recently, the capability to physically produce such a design had been limited by manufacturing constraints. In this study, a commercial adjoint optimization solver was used in conjunction with a conventional flow solver to optimize the design of wavy microchannels, the end use of which can be found in gas turbine airfoil skin cooling schemes. Three objective functions were chosen for two baseline wavy channel designs: minimize the pressure drop between channel inlet and outlet, maximize the heat transfer on the channel walls and maximize the ratio between heat transfer and pressure drop. The optimizer was successful in achieving each objective and generated significant geometric variations from the baseline study. The optimized channels were additively manufactured using Direct Metal Laser Sintering and printed reasonably true to the design intent. Experimental results showed that the high surface roughness in the channels prevented the objective to minimize pressure loss from being fulfilled. However, where heat transfer was to be maximized, the optimized channels showed a corresponding increase in Nusselt number.

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Experimental and theoretical investigation of heat transfer in platform bed during polymer extrusion based additive manufacturing

Polymer Testing ◽

10.1016/j.polymertesting.2018.11.025 ◽

2019 ◽

Vol 73 ◽

pp. 439-446 ◽

Cited By ~ 6

Author(s):

Darshan Ravoori ◽

Christian Lowery ◽

Hardikkumar Prajapati ◽

Ankur Jain

Keyword(s):

Heat Transfer ◽

Additive Manufacturing ◽

Theoretical Investigation ◽

Polymer Extrusion

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Material Flow Rate Estimation in Material Extrusion Additive Manufacturing

10.51843/measure.13.1.5 ◽

2021 ◽

Vol 13 (1) ◽

pp. 46-56

Author(s):

G.P. Greeff

Keyword(s):

Additive Manufacturing ◽

Flow Rate ◽

Material Flow ◽

Fused Deposition Modeling ◽

Volumetric Flow Rate ◽

Cost Effective ◽

Fused Filament Fabrication ◽

Material Extrusion ◽

Fused Deposition ◽

G Code

The additive manufacturing of products promises exciting possibilities. Measurement methodologies, which measure an in-process dataset of these products and interpret the results, are essential. However, before developing such a level of quality assurance several in-process measurands must be realized. One of these is the material flow rate, or rate of adding material during the additive manufacturing process. Yet, measuring this rate directly in material extrusion additive manufacturing presents challenges. This work presents two indirect methods to estimate the volumetric flow rate at the liquefier exit in material extrusion, specifically in Fused Deposition Modeling or Fused Filament Fabrication. The methods are cost effective and may be applied in future sensor integration. The first method is an optical filament feed rate and width measurement and the second is based on the liquefier pressure. Both are used to indirectly estimate the volumetric flow rate. The work also includes a description of linking the G-code command to the final print result, which may be used to create a per extrusion command model of the part.

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A Computational Fluid Dynamics (CFD) Study of Material Flow in Pneumatic Microextrusion (PME) Additive Manufacturing Process

10.1115/1.0003806v ◽

2021 ◽

Author(s):

Ye Jien Yeow ◽

Mohan Yu ◽

James Day ◽

Roozbeh (Ross) Salary

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Additive Manufacturing ◽

Manufacturing Process ◽

Material Flow ◽

Computational Fluid Dynamics Cfd

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A Heat Transfer Finite Element Model for Wire-Arc-Additive-Manufacturing Process

Lecture Notes in Mechanical Engineering - Proceedings of the 8th International Conference on Fracture, Fatigue and Wear ◽

10.1007/978-981-15-9893-7_14 ◽

2021 ◽

pp. 201-215

Author(s):

Y. Ling ◽

J. Ni ◽

Magd Abdel Wahab ◽

J. Antonissen ◽

J. Vande Voorde

Keyword(s):

Heat Transfer ◽

Finite Element ◽

Additive Manufacturing ◽

Finite Element Model ◽

Manufacturing Process ◽

Element Model ◽

Wire Arc Additive Manufacturing

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Computational Investigation of Flow Over Geometry Compliant Lattice Structures

Volume 7: Fluids Engineering ◽

10.1115/imece2018-87846 ◽

2018 ◽

Author(s):

James J. Tinsley ◽

Gregory J. Vernon ◽

Kelly O. Homan

Keyword(s):

Heat Transfer ◽

Additive Manufacturing ◽

Integral Geometry ◽

Single Unit ◽

Unit Cell ◽

Lattice Structures ◽

Computational Investigation ◽

Enhance Heat Transfer ◽

Arbitrary Flow ◽

The U.S

With the increasing prevalence of additive manufacturing, geometries that would not have been possible to manufacture just a few years ago are becoming a reality. One example is the ability to create pipes with integral, geometry compliant lattice structures. These compliant lattice structures offer the potential to greatly enhance heat transfer in arbitrary flow passages. This preliminary paper will focus on the development of an isothermal simulation model in OpenFOAM, to model the nature of the flow for a single unit cell, a unit cell screen, and a series of unit cell screens. Honeywell FM&T is a contractor of the U.S. Government under Contract No. DE-NA0002839.

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Thermal Conductivity Testing Apparatus for 3D Printed Materials

Volume 2: Heat Transfer Equipment; Heat Transfer in Multiphase Systems; Heat Transfer Under Extreme Conditions; Nanoscale Transport Phenomena; Theory and Fundamental Research in Heat Transfer; Thermophysical Properties; Transport Phenomena in Materials Processing and Manufacturing ◽

10.1115/ht2017-4856 ◽

2017 ◽

Cited By ~ 5

Author(s):

Tiffaney Flaata ◽

Gregory J. Michna ◽

Todd Letcher

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Additive Manufacturing ◽

3D Printing ◽

Polymer Composite ◽

Heat Exchangers ◽

Fused Deposition ◽

3D Printed ◽

Printed Materials ◽

Metal Polymer

Additive manufacturing, the layer-by-layer creation of parts, was initially used for rapid prototyping of new designs. Recently, due to the decrease in the cost and increase in the resolution and strength of additively manufactured parts, additive manufacturing is increasingly being used for production of parts for end-use applications. Fused Deposition Modeling (FDM), a type of 3d printing, is a process of additive manufacturing in which a molten thermoplastic material is extruded to create the desired geometry. Many potential heat transfer applications of 3d printed parts, including the development of additively manufactured heat exchangers, exist. In addition, the availability of metal/polymer composite filaments, first used for applications such as tooling for injection molding applications and to improve wear resistance, could lead to increased performance 3d printed heat exchangers because of the higher thermal conductivity of the material. However, the exploitation of 3d printing for heat transfer applications is hindered by a lack of reliable thermal conductivity data for as-printed materials, which typically include significant void fractions. In this experimental study, an apparatus to measure the effective thermal conductivity of 3d printed composite materials was designed and fabricated. Its ability to accurately measure the thermal conductivity of polymers was validated using a sample of acrylic, whose conductivity is well understood. Finally, the thermal conductivities of various 3d printed polymer, metal/polymer composite, and carbon/polymer composite filaments were measured and are reported in this paper. The materials used are acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), stainless steel/PLA, Brass/PLA, and Bronze/PLA.

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