Abstract
A fundamental understanding of how process variables relate to deposit characteristics is essential for solid freeform fabrication (SFF) process control. In this article, recent research into modeling and understanding solidification-related phenomena in laser-based direct metal SFF processes is summarized. A “process map” approach is outlined, which provides nonlinear thermomechanical model results for key deposit characteristics over the full range of relevant process variables. Process maps for predicting melt pool size, thermal gradients and maximum residual stress in thin-walled structures are presented, and process-related insights from them are described. Work underway to develop additional process maps, including those for microstructural control, is also summarized.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
D.L. Bourell et al., “Solid Freeform Fabrication Proceedings (Austin, TX: Univ. of Texas, 1999).
D.L. Bourell et al., editors, Solid Freeform Fabrication Proceedings (Austin, TX: Univ. of Texas, 2000).
S. Das et al., “Producing Metal Parts by Selective Laser Sintering/Hot Isostatic Pressing,” JOM, 50 (12) (1998), pp. 17–20.
T.R. Jackson et al., “Modeling and Designing Functionally Graded Material Components for Fabrication with Local Composition Control,” J. Materials and Design, 20 (2/3) (1999), pp. 63–75.
M.L. Griffith et al., “Freeform Fabrication of Metallic Components Using Laser Engineered Net Shaping (LENS),” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 1996), pp. 125–132.
M.L. Griffith et al., “Understanding Thermal Behavior in the LENS Process,” J. Materials and Design, 20 (2/3) (1999), pp. 107–114.
W.H. Hofmeister et al., “Solidification in Direct Metal Deposition by LENS Processing,” in this issue.
R. Merz et al., “Shape Deposition Manufacturing,” Proc. 1994 Solid Freeform Fabrication Symp., ed. H.L. Marcus et al. (Austin, TX: Univ. of Texas, 1994), pp. 1–8.
R.K. Chin, J.L. Beuth, and C.H. Amon, “Thermomechanical Modeling of Molten Metal Droplet Solidification Applied to Layered Manufacturing,” Mechanics of Materials, 24 (1996), pp. 257–271.
C.H. Amon et al., “Shape Deposition Manufacturing with Microcasting: Processing, Thermal and Mechanical Issues,” J. Manufacturing Sci. and Eng., 120 (3) (1998), pp. 656–665.
R.K. Chin, J.L. Beuth, and C.H. Amon, “Droplet-Level Modeling of Thermal Stresses in Layered Manufacturing Methods” (Paper presented at the ASME Int. Mechanical Eng. Congress and Exposition, Atlanta, November 1996).
R.K. Chin, J.L. Beuth, and C.H. Amon, “Successive Deposition of Metals in Solid Freeform Fabrication Processes Part II: Thermomechanical Models of Adjacent Droplets,” J. Manufacturing Sci. and Eng. (in print).
R.K. Chin, J.L. Beuth, and C.H. Amon, “Thermomechanical Modeling of Successive Material Deposition in Layered Manufacturing,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: University of Texas, 1996), pp. 507–514.
R.K. Chin, J.L. Beuth, and C.H. Amon, “Successive Deposition of Metals in Solid Freeform Fabrication Processes Part I: Thermomechanical Models of Layers and Droplet Columns,” J. Manufacturing Sci. and Eng. (in print).
N.W. Klingbeil, J.W. Zinn, and J.L. Beuth, “Measurement of Residual Stresses in Parts Created by Shape Deposition Manufacturing,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 1997), pp. 125–132.
N.W. Klingbeil et al., “Measurement and Modeling of Residual Stress-Induced Warping in Direct Metal Deposition Processes,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 1998), pp. 367–374.
N.W. Klingbeil et al., “Residual Stress-Induced Warping in Direct Metal Solid Freeform Fabrication,” submitted to the Int. J. Mechanical Sci.
R. Ong, J.L. Beuth, and L.E. Weiss, “Residual Stress Control Issues for Thermal Deposition of Polymers in SFF Processes,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 2000), pp. 209–218.
R.U. Vaidya et al., “Measurement of Bulk Residual Stresses in Molybdenum Disilicide/Stainless Steel Joints Using Neutron Scattering,” Acta Materialia, 46 (6) (1998), pp. 2047–2061.
M.A.M. Bourke et al., “Complementary X-ray and Neutron Strain Measurements of a Carburized Surface,” Materials Sci. & Eng. A, A257 (2) (1998), pp. 333–340.
P. Rangaswami and T.M. Holden, private communication (2001).
P.A. Kobryn, E.H. Moore, and S.L. Semiatin, “The Effect of Laser Power and Transverse Speed on Microstructure, Porosity and Build Height in Laser-Deposited Ti-6Al-4V,” Scripta Mater., 43 (2000), pp. 299–305.
P.A. Kobryn and S.L. Semiatin, “Laser Forming of Ti-6Al-4V: Research Overview,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 2000), CD-ROM.
P.A. Kobryn and S.L. Semiatin, “Laser Additive Manufacturing of Ti-6Al-4V,” in this issue.
A. Vasinonta, J.L. Beuth, and M.L. Griffith, “Process Maps for Laser Deposition of Thin-Walled Structures,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 1999), pp. 383–391.
A. Vasinonta, J.L. Beuth, and M.L. Griffith, “A Process Map for Consistent Build Conditions in the Solid Freeform Fabrication of Thin-Walled Structures,” J. Manufacturing Sci. and Eng. (in print).
A. Vasinonta, J.L. Beuth, and M.L. Griffith, “Process Maps for Controlling Residual Stress and Melt Pool Size in Laser-Based SFF Processes,” Solid Freeform Fabrication Proceedings, ed. D.L. Bourell et al. (Austin, TX: Univ. of Texas, 2000), CD-ROM.
D. Rosenthal, “The Theory of Moving Sources of Heat and Its Application to Metal Treatments,” Transactions of ASME, 68 (1946), pp. 849–866.
B.A. Boley and J.H. Weiner, Theory of Thermal Stresses (New York: John Wiley & Sons, Inc., 1960).
Author information
Authors and Affiliations
Additional information
For more information, contact Jack Beuth, Carnegie Mellon University, Department of Mechanical Engineering, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213-3890; (412) 268-3873; fax (412) 268-3348; e-mail beuth@andrew.cmu.edu.
Rights and permissions
About this article
Cite this article
Beuth, J., Klingbeil, N. The role of process variables in laser-based direct metal solid freeform fabrication. JOM 53, 36–39 (2001). https://doi.org/10.1007/s11837-001-0067-y
Issue Date:
DOI: https://doi.org/10.1007/s11837-001-0067-y