Threshold conditions for thermocapillary formation of a deep cavity in the additive process for selective laser melting of a metal powder layer

2021 ◽  
pp. 1-10
Author(s):  
R.D. Seydgazov ◽  
F. Kh Mirzade
Keyword(s):  
Metal Powder ◽  
Selective Laser Melting ◽  
Powder Layer ◽  
Laser Melting ◽  
Additive Process ◽  
Deep Cavity ◽  
Threshold Conditions

A Powder Shrinkage Model for Describing Real Layer Thickness during Selective Laser Melting Process

2010 ◽  
Vol 97-101 ◽  
pp. 3820-3823 ◽  
Author(s):  
Dan Qing Zhang ◽  
Qi Zhou Cai ◽  
Jin Hui Liu ◽  
Rui Di Li
Keyword(s):  
Layer Thickness ◽  
Metal Powder ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Powder Layer ◽  
Laser Melting ◽  
Selective Laser Melting Process ◽  
Mathematical Explanations ◽  
Total Shrinkage ◽  
Initial Layers

Shrinkage tends to generate when loose metal powder melted in each processing layer along the direction of layer growing during selective laser melting process, resulting in an increased real layer thickness. The shrinkage model for layer shrinkage in SLM process is established. The variation of real layer thickness and the relevant mathematical explanations are discussed in this paper. The results show that the total shrinkage of metal powder layer sharply increases in the initial layers, and then reaches to a plateau value with the increased processing layers. This value is defined by the ratio of sliced layer thickness (h) to relative density (k) during selective laser melting process.

Determination of True Temperature in Selective Laser Melting of Metal Powder Using Infrared Camera

2015 ◽  
Vol 834 ◽  
pp. 93-102 ◽  
Author(s):  
Maria Andreyevna Doubenskaia ◽  
Ivan Vladimirovich Zhirnov ◽  
Vladimir Ilyich Teleshevskiy ◽  
Philippe Bertrand ◽  
Igor Yurievich Smurov
Keyword(s):  
Metal Powder ◽  
Selective Laser Melting ◽  
Molten Pool ◽  
Infrared Camera ◽  
Powder Layer ◽  
True Temperature ◽  
Laser Melting ◽  
Actual Problem ◽  
Ir Camera ◽  
Pool Surface

The objective of this study is to restore the true temperature in during the process of Selective Laser Melting (SLM) of metal powder (in the present case INOX 316L), that is the actual problem in laser assisted additive technologies. To meet this objective, at the first stage, the temperature was measured on the surface of metal substrate INOX 304L without a powder layer. Based on the results of studies the method of temperature measurementof the molten pool surface on metallic plates and during melting of metal powder layer, that were exposed to laser radiation, using an infrared camera (IR), in the present case FLIR Phoenix RDAS TM, was proposed. To restore the true temperature based on the brightness temperature values measured by IR camera, the results of temperature measurements were compared with the width of the molten track on the surface of the plate in the absence of powder. In case of SLM, the results of IR camera measurements were compared with the width of a welded track (bead). The true temperature profiles and temperature gradients values were determined along the axis of the laser beam for melting of plates without powder. In the case of powder melting, the developed method allows to determine the influence of several key SLM parameters on the molten pool shape.

Single Track Formation during Selective Laser Melting of Ti-6Al-4V Alloy

2019 ◽  
Vol 946 ◽  
pp. 978-983 ◽  
Author(s):  
R.M. Baitimerov
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Complex Shape ◽  
Powder Layer ◽  
Single Track ◽  
Laser Melting ◽  
Additive Manufacturing Technology ◽  
Geometrical Characteristics ◽  
Track Formation ◽  
Point Distance

Selective laser melting (SLM) is an additive manufacturing technology that allows to produce functional parts with extremely complex shape from metal powder feedstock. 240 single tracks with the length of 10 mm were fabricated using different SLM process parameters: laser power output, powder layer thickness, point distance and exposure time. Obtained single tracks were measured using optical microscopy. An influence of SLM process parameters on geometrical characteristics of obtained single tracks was investigated.

scholarly journals Numerical Simulation of Moving Heat Flux during Selective Laser Melting of AlSi25 Alloy Powder

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 877
Author(s):  
Cong Ma ◽  
Xianshun Wei ◽  
Biao Yan ◽  
Pengfei Yan
Keyword(s):  
Numerical Simulation ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Molten Pool ◽  
Laser Power ◽  
Scanning Speed ◽  
Powder Layer ◽  
Maximum Temperature ◽  
Three Dimensional Model ◽  
Laser Melting

A single-layer three-dimensional model was created to simulate multi-channel scanning of AlSi25 powder in selective laser melting (SLM) by the finite element method. Thermal behaviors of laser power and scanning speed in the procedure of SLM AlSi25 powder were studied. With the increase of laser power, the maximum temperature, size and cooling rate of the molten pool increase, while the scanning speed decreases. For an expected SLM process, a perfect molten pool can be generated using process parameters of laser power of 180 W and a scanning speed of 200 mm/s. The pool is greater than the width of the scanning interval, the depth of the molten pool is close to scan powder layer thickness, the temperature of the molten pool is higher than the melting point temperature of the powder and the parameters of the width and depth are the highest. To confirm the accuracy of the simulation results of forecasting excellent process parameters, the SLM experiment of forming AlSi25 powder was carried out. The surface morphology of the printed sample is intact without holes and defects, and a satisfactory metallurgical bond between adjacent scanning channels and adjacent scanning layers was achieved. Therefore, the development of numerical simulation in this paper provides an effective method to obtain the best process parameters, which can be used as a choice to further improve SLM process parameters. In the future, metallographic technology can also be implemented to obtain the width-to-depth ratio of the SLM sample molten pool, enhancing the connection between experiment and theory.

Sign in / Sign up

Export Citation Format

Share Document