Thermomechanical models developed in this research address two experimental
observations made during the deposition of thin-walled structures by the LENSTM process. The
first observation (via thermal imaging) is of substantial increases in melt pool size as a vertical
free edge is approached under conditions of constant laser power and velocity. The second
observation (via neutron diffraction) is of large tensile stresses in the vertical direction at vertical
free edges, after deposition is completed and the wall is allowed to cool to room temperature. At
issue is how to best control melt pool size as a free edge is approached and whether such control
will also reduce observed free edge stresses. Thermomechanical model results are presented
which demonstrate that power reduction curves suggested by process maps for melt pool size
under steady-state conditions can be effective in controlling melt pool size as a free edge is
approached. However, to achieve optimal results it is important that power reductions be
initiated before increases in melt pool size are observed. Stress simulations indicate that control
of melt pool size can reduce free-edge stresses; however, the primary cause of these stresses is a
constraint effect which is independent of melt pool size.This research was supported by the National Science Foundation Division of Design,
Manufacture and Industrial Innovation, through the Materials Processing and Manufacturing
Program, award number DMI-0200270.Mechanical Engineerin
