  Topology optimization offers great opportunities to design permanent magnetic
systems that have specific external field characteristics. Additive
manufacturing of polymer bonded magnets with an end-user 3D printer can be used
to manufacture permanent magnets with structures that have been difficult or
impossible to manufacture previously. This work combines these two powerful
methods to design and manufacture permanent magnetic system with specific
properties. The topology optimization framework is simple, fast, and accurate.
It can be also used for reverse engineering of permanent magnets in order to
find the topology from field measurements. Furthermore, a magnetic system that
generate a linear external field above the magnet is presented. With a volume
constraint the amount of magnetic material can be minimized without losing
performance. Simulations and measurements of the printed system show a very
good agreement.
