Shape Deposition Manufacturing With Microcasting: Processing, Thermal and Mechanical Issues

Shape deposition manufacturing (SDM) is a solid freeform fabrication (SFF) methodology for automatically building up material layers to form three-dimensional, complex-shaped, multi-material structures. Microcasting is a molten metal droplet deposition process which is able to create fully dense metal layers with controlled microstructures. SDM combines microcasting with other intermediate processing operations, such as CNC machining and shot peening, to create high quality metal parts. In this paper, a description is given of SDM and the microcasting process. An overview of thermal and mechanical issues associated with SDM and microcasting is presented, including the control of interlayer metallurgical bonding through substrate remelting, the control of cooling rates of both the substrate and the deposited material and the minimization of residual thermal stress effects. Thermal models are used to study the issue of localized remelting of previously deposited material by newly deposited molten droplets to achieve metallurgical bonding. Mechanical modeling provides insight into residual stress build-up during part manufacture and residual stress-driven debonding between deposited layers.

[1]  I. V. Samarasekera,et al.  Mathematical model of the thermal processing of steel ingots: Part II. Stress model , 1987 .

[2]  I. V. Samarasekera,et al.  Mathematical model of the thermal processing of steel ingots: Part I. Heat flow model , 1987 .

[3]  N. J. Grant,et al.  A mathematical model of the spray deposition process , 1989 .

[4]  A. Evans,et al.  A Test Specimen for Determining the Fracture Resistance of Bimaterial Interfaces , 1989 .

[5]  Modelling of heat transfer and solidification during splat cooling : effect of splat thickness and splat/substrate thermal contact , 1991 .

[6]  Owen Richmond,et al.  On the Calculation of Deformations and Stresses During Axially Symmetric Solidification , 1991 .

[7]  Fundamentals of Spray Deposition Via Osprey Processing , 1991 .

[8]  Michel A. Melkanoff,et al.  Laminated Object Manufacturing (LOM): A New Tool in the CIM World , 1992, PROLAMAT.

[9]  J. Szekely,et al.  Fluid flow, heat transfer, and solidification of molten metal droplets impinging on substrates: Comparison of numerical and experimental results , 1992 .

[10]  Lee E. Weiss,et al.  Thermal spray shape deposition , 1992 .

[11]  John O. Milewski,et al.  Directed light fabrication , 1994 .

[12]  D. Poulikakos,et al.  Solidification of Liquid Metal Droplets Impacting Sequentially on a Solid Surface , 1994 .

[13]  Fritz B. Prinz,et al.  THERMAL MODELLING AND EXPERIMENTAL TESTING OF MD* SPRAY SHAPE DEPOSITION PROCESSES , 1994 .

[14]  Chua Chee Kai.  Three-dimensional rapid prototyping technologies and key development areas , 1994 .

[15]  Fritz B. Prinz,et al.  Numerical and Experimental Investigation of Interface Bonding Via Substrate Remelting of an Impinging Molten Metal Droplet , 1996 .

[16]  Cristina H. Amon,et al.  Thermomechanical modeling of molten metal droplet solidification applied to layered manufacturing , 1996 .

[17]  J. L. Beuth,et al.  Residual stress-driven delamination in deposited multi-layers , 1996 .

[18]  J. Beuth,et al.  Axisymmetric delamination in deposited multi-layers , 1997 .

[19]  J. Beuth,et al.  Interfacial fracture testing of deposited metal layers under four-point bending , 1997 .