Great question, and no magic required. For any stent design, one can choose to laser cut the geometry at the constrained diameter, the expanded diameter, or any diameter in between. For stents with a very small constrained diameter (such as intracranial stents), it is often advantageous to laser cut the geometry from a larger diameter tube. This approach requires the designer to create CAD geometry that is matched to the desired tubing diameter, a step that may be aided by finite element analysis or other techniques.

Your question about feature dimensions is also an important one. It is important to plan for material removal after laser cutting, which means designing the laser-cut geometry with features that are larger than your intended final dimensions. The amount of material removal required depends on the specific material and processes that are used. As a starting point, it’s a good idea to assume removal of 20 to 40 µm from feature widths and as much, if not more, from wall thicknesses. This allows for removal of heat-affected zones or draw lines from the inner surface of the tube and results in an optimal surface finish.