Magnetfabrik Bonn (Germany)

The results of studies of solid-state materials using AMD-methods are presented. It is shown that, regardless of the type of structure of the studied materials and their nature, acoustic waves provide subsurface images. The proposed methods allow measuring the velocity of surface acoustic waves and their level of attenuation. These characteristics and acoustic images make it possible to evaluate the parameters of ordering the structure of subsurface layers of materials.

Additive manufacturing of polymer-bonded magnets is a recently developed technique, for single-unit production, and for structures that have been impossible to manufacture previously. Also, new possibilities to create a specific stray field around the magnet are triggered. The current work presents a method to 3D print polymer-bonded magnets with a variable magnetic compound fraction distribution. This means the saturation magnetization can be adjusted during the printing process to obtain a required external field of the manufactured magnets. A low-cost, end-user 3D printer with a mixing extruder is used to mix permanent magnetic filaments with pure polyamide (PA12) filaments. The magnetic filaments are compounded, extruded, and characterized for the printing process. To deduce the quality of the manufactured magnets with a variable magnetic compound fraction, an inverse stray field framework is developed. The effectiveness of the printing process and the simulation method is shown. It can also be used to manufacture magnets that produce a predefined stray field in a given region. This opens new possibilities for magnetic sensor applications. This setup and simulation framework allows the design and manufacturing of polymer-bonded permanent magnets, which are impossible to create with conventional methods.

A new transformer produces magnetic field pulses up to 42 Tesla in field volumes of about 0.1 cm/sup 3/. The transformer combines the current pulses, I, of n (n=1...6) individual capacitor discharge circuits into a single current pulse n/spl middot/I. With n=6, peak currents of I/sub max/=16 kA lead to a secondary peak current of n/spl middot/I/sub max/=580 kA. Thus the product of the currents of the individual primary circuits is large, while each single current and the capacitor voltage remains low.