# Topology Optimized and 3D Printed Polymer Bonded Permanent Magnets for a Predefined External Field

## TL;DR

This paper combines topology optimization and 3D printing to design and manufacture polymer bonded permanent magnets with specific external field characteristics, enabling complex magnetic structures previously difficult to produce.

## Contribution

It introduces a simple, fast topology optimization framework for designing magnetic systems with specific properties, including reverse engineering from field measurements, and demonstrates its application with 3D printed magnets.

## Key findings

- Good agreement between simulations and measurements
- Minimized magnetic material volume while maintaining performance
- Designed magnets generate a linear external field

## Abstract

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.