The direct metal deposition (DMD) process is suitable for functional rapid prototyping, rapid tooling and part refurbishment, and can be operated with CO2, Nd:YAG (neodymium-doped yttrium aluminium garnet) or high-power diode lasers. In this work, a quasi-stationary coaxial DMD system is modelled in terms of power balances. Novel modelling methods and matching to experimental results are used to derive a series of equations, from which the power distribution, melt pool length and mean melt pool temperature can be derived for different initial laser powers, system parameters and build material properties. The model is applied to a real system and predicts results in agreement with established values. The model highlights laser radiation reflection from the melt pool and conduction to the substrate as the major power distribution routes and reveals the importance of evaporation losses from the melt pool at higher laser powers. Application of the model is able to explain some of the differences in the process found when using alternative types of lasers as the power source.
PinkertonA. J.LiL.Rapid prototyping using direct laser deposition—the effect of powder atomisation type and flowrate. Proc. Instn Mech. Engrs, Part B: J. Engineering Manufacture, 2003, 217(B6), 741–752.
MazumderJ.DuttaD.GhoshA.KikuchiN.Designed materials: What and how. Proc. SPIE, 2003, 4831, 505–516.
4.
WohlersT.Wohlers Report—Rapid Prototyping and Tooling State of the Industry, 2002 (Wohlers Associates Inc., Colorado).
5.
LewisG. K.SchliengerE.Practical considerations and capabilities for laser assisted direct metal deposition. Mater. Des., 2000, 21(4), 417–423.
6.
MilewskiJ. O.DickersonP. G.NemecR. B.LewisG. K.FonsecaJ. C.Application of a manufacturing model for the optimization of additive processing of Inconel alloy 690. J. Mater. Processing Technol., 1999, 91(1-3), 18–28.
7.
MazumderJ.ChoiJ.NagarathnamK.KochJ.HetznerD.Direct metal deposition of H13 tool steel for 3-D components. J. Metals, 1997, 49(5), 55–60.
8.
BackesG.KreutzE. W.GasserA.HoffmannE.KetgenS.WissenbachK.PopraweR.Laser-shape reconditioning and manufacturing of tools and machine parts. In Proceedings of ICALEO '98, Orlando, Florida, 1998, pp. E48–56.
9.
PinkertonA. J.LiL.The effect of diode laser beam shape and traverse direction on the direct metal deposition process. In Proceedings of ICALEO '03, Jacksonville, Florida, 2003, CD.
10.
WilsonJ.HawkesJ. F. B.Lasers Principles and Applications, 1987, p. 167 (Prentice-Hall, Englewood Cliffs, New Jersey).
11.
LawrenceJ.The characteristics and feasibility of a two-stage ceramic tile grout sealing process using a high power diode laser. PhD thesis, UMIST, Manchester, 1999, p. 49.
12.
NowotnyS.RichterA.BeyerE.Laser cladding using high-power diode lasers. In Proceedings of ICALEO '98, Orlando, Florida, 1998, pp. G68–74.
13.
TuominenJ.LaurilaJ.VihinenJ.MantylaT.OlaussenL.PeltolaT.Comparison of CO2 and high power diode laser (HPDL) cladding. In Proceedings of ICALEO '02, Scottsdale, Arizona, 2002, CD.
14.
DykhuizenR. C.DobranichD.Scaling analysis for the LENS process. Sandia National Laboratories Internal Report, 1998.
15.
DykhuizenR. C.DobranichD.Scoping thermal calculations for the LENS process. Sandia National Laboratories Internal Report, 1998.
16.
HofmeisterW.GriffithM.EnszM.SmugereskyJ.Solidification in direct metal deposition by LENS processing. J. Metals, 2001, 53(9), 30–34.
17.
GeddaH.PowellJ.WahlstromG.LiW.-BEngstromH.MagnussonC.Energy redistribution during CO2 laser cladding. J. Laser Applic., 2002, 14(2), 78–82.
18.
GeddaH.PowellJ.KaplanA. F. H.A process efficiency comparison of Nd:YAG and CO2 laser cladding. Weld. in the World, Le Soudage dans le Monde, 2002, 46, 75–86.
19.
PinkertonA. J.LiL.Modelling powder concentration distribution from a coaxial deposition nozzle for laser-based rapid tooling. Trans. ASME, J. Mfg Sci. Engng, 2004, 126(1), 34–42.
20.
LinJ.Numerical simulation of the focused powder streams in coaxial laser cladding. J. Mater. Processing Technol., 2000, 105(1), 17–23.
21.
ColacoR.CostaL.GuerraR.VilarR.A simple correlation between the geometry of laser cladding tracks and process parameters. In Proceedings of the NATO Advanced Study Institute on Laser Processing: Surface Treatment and Film Deposition (Eds MazumderJ.), Sesimbra, Portugal, 1994, pp. 421–429.
22.
BeuthJ.KlingbeilN.The role of process variables in laser-based direct metal solid freeform fabrication. J. Metals, 2001, 53(9), 36–39.
McLeanM. A.ShannonG. J.SteenW. M.Laser direct casting high nickel alloy components. Adv. Powder Metallurgy and Particulate Materials, 1997, 3(21), 3–16.
25.
RosenthalD.The theory of moving sources of heat and its application to metal treatments. Trans. Am. Soc. Mineral Engrs, 1946, 68, 849–866.
26.
HofmeisterW. H.MacCallumD. O.KnorovskyG. A.Video monitoring and control of the LENS process. In Proceedings of the 9th International Conference on Computer Technology in Welding, Detroit, Michigan, 1999, pp. 187–196.
27.
LiW.-B.EngstromH.PowellJ.TanZ.MagnussonC.Redistribution of the beam power in laser cladding by powder injection. Lasers in Engng, 1996, 5(3), 175–183.
28.
KizakiY.AzumaH.YamazakiS.SugimotoH.TakagiS.Phenomenological studies in laser cladding. Part 1. Time-resolved measurements of the absorptivity of metal powder. Jap. J. Appl. Physics, 1993, 32, 205–212.
29.
LinJ.Temperature analysis of the powder streams in coaxial laser cladding. Optics and Laser Technol., 1999, 31, 565–570.
30.
Diniz NetoO. O.VilarR.Physical-computational model to describe the interaction between a laser beam and a powder jet in laser surface processing. J. Laser Applic., 2002, 14(1), 46–51.
31.
Diniz NetoO. O.VilarR.Interaction between the laser beam and the powder jet in blown powder laser alloying and cladding. In Proceedings of ICALEO '98, Orlando, Florida, 1998, pp. D180–188.
32.
PicassoM.RappazM.Laser-powder-material interactions in the laser cladding process. J. De Physique, 1994, 4(4), 27–33.
33.
SternG.Absorptivity of cw CO2, CO and YAG laser beams by different metallic alloys. In Proceedings of the 3rd European Conference on Laser Treatment of Materials, (ECLAT), 1990, pp. 25–35.
34.
BambergerM.GelerM.Energy coupling between CO2-laser irradiation and metallic substrates. Lasers in Engng, 1997, 6(3), 213–234.
35.
DuleyW. W.Laser material interactions of relevance to metal surface treatment. In Laser Surface Treatment of Metals (Eds DraperC. W.MazzsoldiP.), 1986, pp. 3–16 (Martinus Nijhoff Publishers, Dortrecht, The Netherlands).
36.
PantsarH.KujanpaaV.The absorption of a diode laser beam in laser surface hardening of a low alloy steel. In Proceedings of ICALEO '02, Scottsdale, Arizona, 2002, CD.
37.
XieJ.KarA.Laser welding of thin sheet steel with surface oxidation. Am. Weld. Soc. Weld. J. Res. Suppl., 1999, 343s–348s.
38.
BambergerM.On energy coupling between laser radiation and materials. Lasers in Engng, 1999, 9(2), 139–156.
39.
BloesW.GrunenvaldB.DausingerF.HugelH.Recent progress in laser surface treatment: I. Implications of laser wavelength. J. Laser Applic., 1996, 8, 15–23.
40.
FungC.-P.PengK.-P.DoongJ.-L.Study of surface temperature on laser cutting and welding power absorption. Int. Communs in Heat and Mass Transfer, 1990, 17(2), 147–154.
41.
KujanpaaV.MaaranenP.KostamoT.Effect of parameters in diode laser welding of steel sheets. Proc. SPIE, 2003, 4831, 38–43.
42.
CarslowH. S.JaegerJ. C.Conduction of Heat in Solids, 2nd edition, 1959, pp. 327–352 (Oxford University Press, Oxford).
43.
IncroperaF. P.DeWittD. P.Fundamentals of Heat and Mass Transfer, 5th edition, 2002, Appendix C, pp. 939–945 (John Wiley, New York).
44.
GeddaH.PowellJ.KaplanA. F. H.A process efficiency comparison of Nd:YAG and CO2 laser cladding. Weld, in the World, Le Soudage dans le Monde, 2002, 46, 75–86.
45.
YangL. X.PengX. F.WangB. X.Numerical modeling and experimental investigation on the characteristics of molten pool during laser processing. Int. J. Heat and Mass Transfer, 2001, 44(23), 4465–4473.
46.
ChoiM.GreifR.SalcudeanM.A study of the heat transfer during arc welding with applications to pure metals or alloys and low or high boiling temperature materials. Numer. Heat Transfer, 1987, 11, 477–489.
47.
LandramC. S.Measurement of fusion boundary energy transport during arc welding. Trans. ASME, Ser. C: J. Heat Transfer, 1983, 105, 550–554.
48.
SalcudeanM.ChoiM.GreifR.A study of heat transfer during arc welding. Int. J. Heat and Mass Transfer, 1986, 29(2), 215–225.
49.
MazumderJ.SteenW. M.Heat transfer model for cw laser processing. J. Appl. Physics, 1980, 51(2), 941–947.
VasinontaA.BeuthJ.GriffithM.Process maps for laser deposition of thin-walled structures. In Proceedings of the 10th Solid Freeform Fabrication Symposium, University of Texas, Austin, Texas, 1999, pp. 383–391.
52.
VasinontaA.BeuthJ.OngR.Melt pool size control in thin-walled and bulky parts via process maps. In Proceedings of the 12th Solid Freeform Fabrication Symposium, University of Texas, Austin, Texas, 2001, pp. 432–440.
PinkertonA. J.LiL.Direct metal deposition by laser—modelling the effect of increased beam coupling. In Proceedings of ICALEO '03, Jacksonville, Florida, 2003, CD.
