Prakt. Met. Sonderband 52 (2018) 247 
MICROSTRUCTURE AND MAGNETIC PROPERTIES OF 
En POLYMER BONDED MAGNETS PRODUCED BY ADDITIVE 
MANUFACTURING TECHNOLOGIES 
M. Brungko', I. AnZel’ 
University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, Si-2000 Maribor, 
Slovenia 
ACOust 
ity ABSTRACT 
“Muay Polymer bonded Nd-Fe-B magnets belong to the group of composite materials, which 
| consist mainly of two components: a polymer binder (PPS, PA) and magnetic particles of 
‘ Ky Nd-Fe-B alloy. The appropriate amounts of polymer binder, magnetic powder and additives 
oo are compounded by the twin screw extruder into a compound, that can be then injection 
LINO; ag moulded into a multi-cavity die in the final products of complex shapes in large series. The 
introduction of 3D printing using the method of Fused Deposition Modelling (FDM) as an 
And Diclecrsy alternative technology for the production of polymer bonded magnets is aimed at lowering 
413 costs of a small-scale production while preserving good magnetic and mechanical 
Astribution and properties, such as those obtainable by injection moulding. The purpose of the research 
I Bir Corp work was to identify: (i) the optimal composition and properties of compound (filament) used 
for 3D printing of polymer bonded magnets and (ii) finally the optimal processing parameters 
ng the effect of 3D printing, which would give printed polymer bonded magnets characteristics similar to 
Se those produced by injection moulding. The microstructures of polymer bonded magnets 
dL sures were examined by metallographic techniques, namely optical and scanning electron 
2. microscopy. Additionally, the influence of the processing parameters on the microstructure 
Sting ui dritt and subsequent magnetic properties of the prepared magnets will be discussed. 
2 Rectapor'r The research work has shown that the target properties of polymer bonded magnets are 
obtainable with the reduction of thickness of the printed layer. The hypothesis that the new 
sack Growth is production method FDM enables manufacturing of polymer bonded magnets with the 
properties appropriate for industrial needs has also been confirmed. The results of this 
eneralstabens research work encourage further investigation into the development of the technology of 3D 
printing of polymer bonded magnets on the industrial scale. 
Tests at Room 
AL ne 
1. INTRODUCTION 
re analysis of 
Nowadays, in the information age, the polymer bonded magnets play a vital role as 
RC Atormietid components in a wide range of devices (motors, sensors, actuators, acoustic transducers,). 
NEO: spot The demand in polymer bonded magnets is now the largest in the automotive, aviation 
industry and consumer electronics with an annual growth of sales in the global market of 
oa” over 30%. Originally, in the 70's the polymer bonded magnets were made from ferrite 
powder and elastomers as a binder in a flexible form. To date, the powder may be also made 
from Nd-Fe-B or Sm-Co alloys and the binder form thermosets (epoxy) or thermoplastics 
(PA. PPS). The bonded magnets are composed of NdFeB magnetic powder and polymer