The laser forming of metallic components using particulate materials

Keicher, David M; Smugeresky, John E.

doi:10.1007/bf02914686

Cited by 60 publications

(38 citation statements)

References 4 publications

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“…On the other hand, the system that supplies the feedstock material in wire form offers higher deposition efficiency, less expensive feedstock material and lower material wastage when comparing with powder. Nevertheless, unstable material feed rate control, reduced variety of materials, radiation absorption dependence on surface finish of wire and higher dilution of the deposited material with the substrate are some shortcomings of wire-based processes [12].…”

Section: Laser Metal Depositionmentioning

confidence: 99%

Additive Manufacturing of H11 with Wire-Based Laser Metal Deposition

2017

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Laser additive manufacturing (LAM) is a near-net-shape production technique by which a part can be built up from 3D CAD model data, without material removal. Recently, these production processes gained attention due to the spreading of polymer-based processes in private and commercial applications. However, due to the insufficient development of metal producing processes regarding design, process information and qualification, resistance on producing functional components with this technology is still present. To overcome this restriction further studies have to be undertaken. The present research proposes a parametric study of additive manufacturing of hot work tool steel, H11. The selected LAM process is wire-based laser metal deposition (LMD-W). The study consists of parameters optimization for single beads (laser power, travel speed and wire feed rate) as well as lateral and vertical overlap for layer-by-layer technique involved in LMD process. Results show that selection of an ideal set of parameters affects substantially the surface quality, bead uniformity and bond between substrate and clad. Discussion includes the role of overlapping on the soundness of parts based on the height homogeneity of each layer, porosity and the presence of gaps. For the conditions tested it was shown that once the deposition parameters are selected, lateral and vertical overlapping determines the integrity and quality of parts processed by LAM. Key-words:Laser additive manufacturing; Hot work tool steel; Parametric study; LMD-W. Manufatura Aditiva do Aço Ferramenta H11 por Deposição Metálica de Arame a LaserResumo: Manufatura aditiva a laser é uma técnica de produção por camadas na qual uma peça pode ser produzida a partir de um modelo 3D sem remoção de material. Recentemente, esses processos ganharam atenção devido à disseminação de processos com polímeros em aplicações privadas e comerciais. Entretanto, devido ao desenvolvimento insuficiente da manufatura aditiva com metais há uma resistência na produção de componentes funcionais com esta tecnologia. Portanto, para superar essa limitação, o presente artigo propõe um estudo nos parâmetros de processo de deposição metálica de arame a laser (LMD-W) do aço ferramenta para trabalho a quente, H11. O estudo consiste na otimização de parâmetros para cordões individuais (potência do laser, velocidade de deslocamento e de alimentação do arame), bem como sobreposição lateral e vertical para a técnica de camada por camada envolvida no processo. Os resultados mostram que a seleção de um conjunto ideal de parâmetros afeta substancialmente a qualidade superficial, a uniformidade dos cordões e a aderência entre o substrato e o cordão. A discussão ainda inclui a função da sobreposição na estabilidade do processo em relação à homogeneidade da altura de cada camada, porosidade e presença de falhas. Foi comprovado que após a seleção dos parâmetros de deposição, a sobreposição lateral e vertical determina a integridade e qualidade das peças manufaturadas aditivamente. Palavras-chave:M...

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Section: Laser Metal Depositionmentioning

confidence: 99%

Additive Manufacturing of H11 with Wire-Based Laser Metal Deposition

2017

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“…Equation [1] is used next to estimate the corresponding layerwise variation in cell spacing. For the estimation of yield strength, it is hypothesized that in a cellular structure, cell spacing, which is much finer than grain size, would correlate well with the material yield strength (or hardness).…”

Section: Estimation Of Cooling Rate Cell Spacing and Hardnessmentioning

confidence: 99%

“…[1][2][3] Powders are carried through an inert gas and delivered concentrically to the laser spot through suitably angled four nozzles placed in the deposition head. After deposition of each layer, the laser head and the powder delivery nozzles are moved upward to deposit the subsequent layers from bottom to top.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Melt Pool Dimensions, Thermal Cycle, and Hardness Distribution in the Laser-Engineered Net Shaping Process of Austenitic Stainless Steel

Manvatkar

Gokhale

Reddy

et al. 2011

Metall Mater Trans A

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Laser engineered net shaping (LENS) and other similar processes facilitate building of parts with freeform shapes by melting and deposition of metallic powders layer by layer. A-priori estimation of the layerwise variations in peak temperature, build dimension, cooling rate, and mechanical property is requisite for successful application of these processes. We present here an integrated approach to estimate these build attributes. A three-dimensional (3-D) heat transfer analysis based on the finite element method is developed to compute the layerwise variation in thermal cycles and melt pool dimensions in the single-line multilayer wall structure of austenitic stainless steel. The computed values of cooling rates during solidification are used to estimate the layerwise variation in cell spacing of the solidified structure. A Hall-Petch like relation using cell size as the structural parameter is used next to estimate the layerwise hardness distribution.The predicted values of layer widths and build heights have depicted fair agreement with the corresponding measured values in actual deposits. The estimated values of layerwise cell spacing and hardness remain underpredicted and overpredicted, respectively. The slight underprediction of the cell spacing is attributed to the possible overestimation of the cooling rates that may have resulted due to the neglect of convective heat transport within the melt pool. The overprediction of the layerwise hardness is certainly due to the underprediction of corresponding cell spacing. The application of Hall-Petch coefficients, which is strictly valid for wrought and annealed grain structures, to estimate the hardness of as-solidified cellular structures may have also contributed to the overprediction of the layerwise hardness.

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“…[6,7] The total heat content absorbed by the substrate (E cal ) was determined by integrating the resultant output voltage vs time signal and then multiplying that quantity by the calorimeter calibration constant (0.598 W/V). Laser energy transfer efficiency ( a ) was then calculated by [1] where E cal ϭ total energy absorbed by the workpiece (J), P ϭ laser output power (W or J/s), and t ϭ laser "on time" (s). In order to examine the effects of surface roughness on laser beam absorption, the H-13 tool steel substrates were prepared by first performing a grinding step with 120-grit sandpaper to remove mill scale, surface scratches, and any other irregularities that were present on the outer extremities of the material in the as-received condition.…”

Section: A Laser Energy Transfer Efficiency Measurementsmentioning

confidence: 99%

“…[1,2,3] However, a fundamental investigation of laser material interaction in the LENS process is still needed to fully understand the laser deposition process. In order for this to occur, it is essential to conduct research on the effects of processing parameters on heat flow and solidification behavior of the LENS process.…”

Section: Introductionmentioning

confidence: 99%

Process efficiency measurements in the laser engineered net shaping process

Unocic

DuPont

2004

Metall Mater Trans B

125

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A study of laser energy transfer efficiency, melting efficiency, and deposition efficiency has been conducted for the laser-engineered net-shaping process (LENS) for H-13 tool steel and copper powder deposits on H-13 tool steel substrates. This study focused on the effects of laser deposition processing parameters (laser power, travel speed, and powder mass flow rate) on laser beam absorption by the substrate material. Measurements revealed that laser energy transfer efficiency ranged from 30 to 50 pct. Laser beam coupling was found to be relatively insensitive to the range of processing parameters tested. Melting efficiency was found to increase with increasing laser input power, travel speed, and powder mass flow rate. A dimensionless parameter model that has been used to predict melting efficiency for laser beam welding processing was investigated for the LENS process. From these results, a semiempirical model was developed specifically for the LENS processing window. Deposition efficiency was also investigated and results show that under optimum processing conditions, the maximum deposition efficiency was approximately 14 pct. A semiempirical relation was developed to estimate deposition efficiency as a function of process efficiencies and LENS processing parameters. Knowledge of LENS process efficiencies measured in this study is useful to develop accurate heat flow and solidification models for the LENS process.

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The laser forming of metallic components using particulate materials

Cited by 60 publications

References 4 publications

Additive Manufacturing of H11 with Wire-Based Laser Metal Deposition

Additive Manufacturing of H11 with Wire-Based Laser Metal Deposition

Estimation of Melt Pool Dimensions, Thermal Cycle, and Hardness Distribution in the Laser-Engineered Net Shaping Process of Austenitic Stainless Steel

Process efficiency measurements in the laser engineered net shaping process

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