Thermal process simulation of droplet based metal printing with aluminium

Droplet based additive manufacturing is a branch of novel processes to build full dense metal parts by adding material droplet by droplet on a build platform. As each droplet solidifies individually upon contact, the quality of bonding to the existing material is determined by the adjacent surface temperatures and the temperature of the arriving droplet. To design a manufacturing process that ensures good bonds between all droplets, it is necessary to understand the relations between process parameters, the part’s geometry and thermal conditions for each arriving droplet. This paper presents a thermal simulation model that is based on Flow 3D software. By adding a user routine to the solver, it is possible to simulate the building process of a part consisting of several thousand droplets with an acceptable effort. This simulation is used to study the effect of production parameters (substrate temperature, droplet temperature and deposition frequency) as well as the parts geometry (layer size and height) on the resultant temperature field. The model was successfully validated with experimental data and can deliver valuable information during further development of this additive manufacturing process.

[1]  B. Lu,et al.  Numerical and experimental investigation of molten metal droplet deposition applied to rapid prototyping , 2016 .

[2]  Zhengying Wei,et al.  Numerical analysis of pileup process in metal microdroplet deposition manufacture , 2015 .

[3]  Zhaoxia Zhai,et al.  Effect of depletion layer width on electrical properties of semiconductive thin film gas sensor: a numerical study based on the gradient-distributed oxygen vacancy model , 2016 .

[4]  Tianjiao Wang,et al.  In-situ Droplet Inspection and Control System for Liquid Metal Jet 3D Printing Process , 2017 .

[5]  Edward P. Furlani,et al.  Drop-on-Demand 3D Metal Printing , 2017 .

[6]  Dimos Poulikakos,et al.  Heat transfer and fluid dynamics during the collision of a liquid droplet on a substrate—II. Experiments , 1996 .

[7]  Qi Lehua,et al.  3D Dynamic Simulation Analysis of Thermal-Mechanical Coupling during 7075 Aluminum Alloy Micro-droplet Deposition Manufacture , 2016 .

[8]  C. W. Hirt,et al.  Volume of fluid (VOF) method for the dynamics of free boundaries , 1981 .

[9]  Dimos Poulikakos,et al.  Experimental investigation of the transient impact fluid dynamics and solidification of a molten microdroplet pile-up , 2003 .

[10]  Eric F. Matthys,et al.  Melting and resolidification of a substrate in contact with a molten metal: operational maps , 1998 .

[11]  Wagner Enno,et al.  純FC‐84及びFC‐3284及びその二元混合物の核沸騰における高分解能測定 , 2009 .

[12]  Ampere A. Tseng,et al.  Design and Operation of a Droplet Deposition System for Freeform Fabrication of Metal Parts , 1999, The Science, Automation, and Control of Material Processes Involving Coupled Transport and Rheology Changes.

[13]  T. Lueth,et al.  A fast pneumatic droplet generator for the ejection of molten aluminum , 2017, 2017 Pan Pacific Microelectronics Symposium (Pan Pacific).

[14]  Jun Luo,et al.  Direct fabrication of unsupported inclined aluminum pillars based on uniform micro droplets deposition , 2017 .

[15]  Q Liu,et al.  On precision droplet-based net-form manufacturing technology , 2001 .

[16]  Hejun Li,et al.  Effect of non-isothermal deposition on surface morphology and microstructure of uniform molten aluminum alloy droplets applied to three-dimensional printing , 2015 .

[17]  T. Lueth,et al.  A novel piezoelectric printhead for high melting point liquid metals , 2016, 2016 Pan Pacific Microelectronics Symposium (Pan Pacific).

[18]  Yuanhai Xiao,et al.  Manufacturing of micro thin-walled metal parts by micro-droplet deposition , 2012 .

[19]  K. Mills.  Recommended Values of Thermophysical Properties for Selected Commercial Alloys , 2001 .

[20]  Jun Luo,et al.  Simulation on deposition and solidification processes of 7075 Al alloy droplets in 3D printing technology , 2014 .

[21]  Javad Mostaghimi,et al.  Deposition of tin droplets on a steel plate: simulations and experiments , 1998 .

[22]  Modelling of Uniform Micron-sized Metal Particles Production Using Harmonic Mechanical Excitation , 2014 .

[23]  Ain A. Sonin,et al.  Motion and arrest of a molten contact line on a cold surface: An experimental study , 1997 .

[24]  Frank Bernhard,et al.  Handbuch der Technischen Temperaturmessung , 2014 .

[25]  Hejun Li,et al.  Remelting and bonding of deposited aluminum alloy droplets under different droplet and substrate temperatures in metal droplet deposition manufacture , 2013 .

[26]  Chul B. Park,et al.  Building three‐dimensional objects by deposition of molten metal droplets , 2008 .

[27]  Lehua Qi,et al.  3D numerical simulation of successive deposition of uniform molten Al droplets on a moving substrate and experimental validation , 2012 .

[28]  Chul B. Park,et al.  Heat Transfer During Deposition of Molten Aluminum Alloy Droplets to Build Vertical Columns , 2009 .

[29]  Javad Mostaghimi,et al.  Interactions between molten metal droplets impinging on a solid surface , 2003 .

[30]  Wenbin Cao,et al.  Freeform fabrication of aluminum parts by direct deposition of molten aluminum , 2006 .