scholarly journals Investigations on Temperature Fields during Laser Beam Melting by Means of Process Monitoring and Multiscale Process Modelling

2014 ◽  
Vol 6 ◽  
pp. 217584 ◽  
Author(s):  
J. Schilp ◽  
C. Seidel ◽  
H. Krauss ◽  
J. Weirather
Keyword(s):  
Process Monitoring ◽  
Manufacturing Process ◽  
Computation Time ◽  
Simulation Models ◽  
Process Models ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Transient Temperature Field ◽  
Laser Beam Melting ◽  
Simulation Based

Process monitoring and modelling can contribute to fostering the industrial relevance of additive manufacturing. Process related temperature gradients and thermal inhomogeneities cause residual stresses, and distortions and influence the microstructure. Variations in wall thickness can cause heat accumulations. These occur predominantly in filigree part areas and can be detected by utilizing off-axis thermographic monitoring during the manufacturing process. In addition, numerical simulation models on the scale of whole parts can enable an analysis of temperature fields upstream to the build process. In a microscale domain, modelling of several exposed single hatches allows temperature investigations at a high spatial and temporal resolution. Within this paper, FEM-based micro- and macroscale modelling approaches as well as an experimental setup for thermographic monitoring are introduced. By discussing and comparing experimental data with simulation results in terms of temperature distributions both the potential of numerical approaches and the complexity of determining suitable computation time efficient process models are demonstrated. This paper contributes to the vision of adjusting the transient temperature field during manufacturing in order to improve the resulting part's quality by simulation based process design upstream to the build process and the inline process monitoring.

Laser Welding Analysis and Experiments

1995 ◽  
Vol 11 (02) ◽  
pp. 102-110 ◽  
Author(s):  
Jon J. Yagla ◽  
Richard S. Haag ◽  
Matthew E. Scott
Keyword(s):  
Laser Welding ◽  
Carbon Dioxide Laser ◽  
Mechanical Design ◽  
Steel Plates ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Heating And Cooling ◽  
Transient Temperature Field ◽  
Welding Steel ◽  
Five Axis

A "seamless engineering" approach for mechanical design and laser welding manufacturing combines a method for welding analysis with a method for stress analysis through the development of radiant heating models for use in a nonlinear finite-element computer program. Experiments were performed welding steel plates, using a five-axis computer numerical controlled (CNC) workstation to translate welding specimens under a 5-kW CO2 (carbon dioxide) laser. Thermocouples installed near the weld seam were used to measure the transient temperature field during welding. The measured temperatures were compared with the analytical predictions, and the welds were sectioned so that predictions of properties in the heat-affected zone could be compared with experimental data. This paper presents analytical results using classical methods of analysis and includes solutions for temperature fields, heating and cooling rates, and metallurgical properties in heat-affected zones.

Thermal Characteristics Analysis of Aerostatic Direct Drive Rotary Stage

2013 ◽  
Vol 655-657 ◽  
pp. 287-291
Author(s):  
Cong Peng Zhang ◽  
Mei Bo Li ◽  
Xue Ke Luo
Keyword(s):  
Heat Dissipation ◽  
Thermal Structure ◽  
Thermal Characteristics ◽  
Simulation Models ◽  
Structural Deformation ◽  
Transient Temperature ◽  
Direct Drive ◽  
Rotary Stage ◽  
Transient Temperature Field ◽  
Characteristics Analysis

A precision air bearing rotary stage driven by direct-driven motor is proposed. The structural characteristic of the rotary system is introduced, and the mechanism of structural thermal deformation and heat dissipation of aerostatic direct drive rotary stage were analyzed. The simulation models of static and transient temperature field are built, and thermal-structure coupled filed is calculated. The internal steady thermal field diagram and key nodes temperature curve of the rotary stage are obtained. Based on the temperature analysis results, the rotary stage structural deformation is established. The cooling method is provided, and result shows that the cooling way is effective.

scholarly journals A simulation-based approach to identify bottlenecks in the bearing manufacturing process

2021 ◽  
Vol 12 (9) ◽  
pp. s843-s855
Author(s):  
Larissa Moreira Alves de Souza Souza ◽  
Adriano Maniçoba da Silva ◽  
Julio Maria de Souza ◽  
Regis Cortez Bueno ◽  
Sivanilza Teixeira Machado ◽  
...  
Keyword(s):  
Physical Environment ◽  
Manufacturing Process ◽  
Flexible Manufacturing ◽  
Simulation Models ◽  
Manufacturing Processes ◽  
Modeling Simulation ◽  
Simulation Based ◽  
Low Costs ◽  
Short Time

Flexible manufacturing processes improve profitability and competitiveness for the company through an efficient process, with quality in a short time, and contribute to achieving low costs. One of the approaches that have been currently developed to improve the flexible manufacturing process is simulation. Simulation models consist of an assertive and powerful tool in strategic planning.  It permits a controlled way of the company's reality so that it was possible to study and analyze the organization's current situation under several circumstances without altering the production's physical environment and involving low costs. Accordingly, this study's primary purpose was to develop a simulation model to verify bottlenecks' existence in the bearing manufacturing process. For this, a case study is presented, and it was used modeling/simulation with Arena Software as a research method. The results showed no bottlenecks in the manufacturing process.

Transient Temperature Field Analysis in Laser Cladding Processing

2012 ◽  
Vol 538-541 ◽  
pp. 1874-1877 ◽  
Author(s):  
Shuai Zhang ◽  
Yan Ling Tian ◽  
Fu Jun Wang
Keyword(s):  
Laser Cladding ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Field Analysis ◽  
Temperature Fields ◽  
Transient Temperature ◽  
3 Dimensional ◽  
Melt Pool ◽  
Transient Temperature Field ◽  
Temperature Filed

A 3-dimensional (3D) thermal distribution computational methodology for laser cladding is presented. Based on the developed model, which considers the latent heat and change of conductivity in different phase, the transient temperature fields for the preplaced laser cladding processing are performed. The effect of processing parameters including laser power, scanning speed and laser spot diameter on melt pool temperature filed was extensively discussed and some conclusions were drawn.

Study on Simulation of Temperature Field and Optimization of Structure to Grounding Resistor

2014 ◽  
Vol 986-987 ◽  
pp. 1864-1868
Author(s):  
Da Jiang He ◽  
Peng Fei Shao ◽  
Hen Ling Yang ◽  
Jing Xiao ◽  
Jun Qu
Keyword(s):  
Temperature Field ◽  
Cost Saving ◽  
Engineering Application ◽  
Structure Optimization ◽  
Simulation Models ◽  
Transient Temperature ◽  
Distribution Characteristics ◽  
Design Efficiency ◽  
Transient Temperature Field ◽  
The Cost

According to the structure of grounding resistor, the flow-current experiments of alloy materials which have different performance and specification have been done in the condition of simulation grounding fault. Based on the experiments, the simulation models of temperature field have been constructed; the distribution characteristics of the transient temperature field and the structure optimization of Grounding Resistor have been studied and discussed by the simulation models. The research results have a great engineering application value on the optimization of performance, the choice of the materials, the cost saving and the improvement of design efficiency to grounding resistor.

Experimental and Numerical Investigation of Temperature Fields in a Radial Turbine Wheel

2014 ◽  
Author(s):  
Mathias Diefenthal ◽  
Hailu Tadesse ◽  
Christian Rakut ◽  
Manfred Wirsum ◽  
Tom Heuer
Keyword(s):  
Temperature Distribution ◽  
Thermal Stresses ◽  
Commercial Vehicle ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Turbine Wheel ◽  
Numerical Investigations ◽  
Transient Temperature Distribution ◽  
Transient Temperature Field ◽  
Transient Operations

Due to increasing demands on the efficiency of modern Otto and Diesel engines, turbochargers are subjected to higher temperatures. In consequence rotor speed and temperature gradients in transient operations are more severe and therefore thermal and centrifugal stresses increase. To determine the life cycle of turbochargers more precisely, the exact knowledge of the transient temperature distribution in the turbine wheel is essential. To assess these temperature distributions, experimental and numerical investigations on a turbocharger of a commercial vehicle were performed. For this purpose, four thermocouples were applied on the shaft and the turbine wheel. The measured temperatures are used to determine the boundary conditions for the numerical calculations and to validate the results. In the numerical investigations three methods are used to determine and to analyse the transient solid body temperature distribution in respect of the fluid. The methods are compared and evaluated using the measured data. Based on the calculations the transient temperature field is discussed and conclusions concerning to the thermal stresses are drawn.

scholarly journals Deep neural networks as surrogate models for time-efficient manufacturing process optimisation

2021 ◽  
Author(s):  
Clemens Zimmerling ◽  
Patrick Schindler ◽  
Julian Seuffert ◽  
Luise Kärger
Keyword(s):  
Evolutionary Algorithms ◽  
Manufacturing Process ◽  
Predictive Accuracy ◽  
Simulation Models ◽  
Relevant Information ◽  
General Purpose ◽  
Process Models ◽  
Process Optimisation ◽  
Dimensional Parameter ◽  
Usable Information

Manufacturing process optimisation usually amounts to searching optima in high-dimensional parameter spaces. In industrial practice, this search is most often directed by human-subjective expert judgment and trial-and-error experiments. In contrast, high-fidelity simulation models in combination with general-purpose optimisation algorithms, e.g. finite element models and evolutionary algorithms, enable a methodological, virtual process exploration and optimisation. However, reliable process models generally entail significant computation times, which often renders classical, iterative optimisation impracticable. Thus, efficiency is a key factor in optimisation. One option to increase efficiency is surrogate-based optimisation (SBO): SBO seeks to reduce the overall computational load by constructing a numerically inexpensive, data-driven approximation („surrogate“) of the expensive simulation. Traditionally, classical regression techniques are applied for surrogate construction. However, they typically predict a predefined, scalar performance metric only, which limits the amount of usable information gained from simulations. The advent of machine learning (ML) techniques introduces additional options for surrogates: in this work, a deep neural network (DNN) is trained to predict the full strain field instead of a single scalar during textile forming („draping“). Results reveal an improved predictive accuracy as more process-relevant information from the supplied simulations can be extracted. Application of the DNN in an SBO- framework for blank holder optimisation shows improved convergence compared to classical evolutionary algorithms. Thus, DNNs are a promising option for future surrogates in SBO.

Transient Temperature During the Vaporization of Liquid on a Pulsed Laser-Heated Solid Surface

1996 ◽  
Vol 118 (3) ◽  
pp. 702-708 ◽  
Author(s):  
H. K. Park ◽  
X. Zhang ◽  
C. P. Grigoropoulos ◽  
C. C. Poon ◽  
A. C. Tam
Keyword(s):  
Thin Film ◽  
Solid Surface ◽  
Elevated Temperatures ◽  
Bubble Nucleation ◽  
Transient Temperature ◽  
Specular Reflectance ◽  
Transient Temperature Field ◽  
Excimer Laser Pulse ◽  
Nanosecond Time Resolution ◽  
Laser Heated

The thermodynamics of the rapid vaporization of a liquid on a solid surface heated by an excimer laser pulse is studied experimentally. The transient temperature field is measured by monitoring the photothermal reflectance of an embedded thin film in nanosecond time resolution. The transient reflectivity is calibrated by considering a temperature gradient across the sample based on the static measurements of the thin film optical properties at elevated temperatures. The dynamics of bubble nucleation, growth, and collapse is detected by probing the optical specular reflectance. The metastability behavior of the liquid and the criterion for the onset of liquid–vapor phase transition in nanosecond time scale are obtained quantitatively for the first time.

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