# Optimization for Achieving Part Quality and Minimum Energy

- Optimal Part Orientation to Achieve Geometric Tolerances
- Process energy analysis and optimization in selective laser sintering

Siemens PLM NX API is used to extract the GD&T callouts and associated geometric information of the CAD model. The mathematical relationships between build
orientation and GD&T Tolerances are developed as part of a combined optimization model to identify best build orientations for minimizing support structures
while meeting the design tolerances.

The feasible build orientations along with the corresponding support structures are depicted using a visual model. The regions requiring support structures
are identified and a Quadtree decomposition is used to find the volume of support structures.

The tolerances studied in this research are: Perpendicularity, Parallelism, Angularity, Conicity, Total Runout and Circular Runout.

** Figure: (a)Part CAD Model with GD&T callouts; (b)Representation of Support Structure and Tolerances for all part orientations;
(c)Verification of all GD&T callouts by graphical approach **

The laser energy expenditure of SLS process and its correlation to the geometry of the manufactured part and the SLS process parameters, however,
have not received much attention from AM/SLS researchers. This research presents a mathematical analysis of the laser energy required for manufacturing
simple parts using the SLS process.

The total energy expended is calculated as a function of the total area of sintering (TAS) using a convex hull based approach and is correlated to
the part geometry, slice thickness and the build orientation. The TAS and laser energy are calculated for three sample parts and the results are provided
in the paper.

Finally, an optimization model is presented which computes the minimal TAS and energy required for manufacturing a part using the SLS process.

** Figure: Test Part, a) Response Surface for Energy vs Part Orientation and b) Energy Contour Map **

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