Influence of the structure and injection moulding parameters on the maximum energy product (BH)max of the dielectromagnets
Lech Paszkowski, Andrzej Skalski, Dionizy Biało Politechnika Warszawska, Wydział Mechatroniki, Instytut Inżynierii Precyzyjnej i Biomedycznej, ul. św. A. Boboli 8, 02-525 Warszawa, Poland
Quarterly No. 3, 2008 pages 280-284
DOI:
keywords: dielectromagnets, magnetic powder, injection moulding, maximum energy product
abstract One of the production methods of dielektromagnets is injection moulding. This technology applied was in presented paper. Special moulded samples were prepared for analysis of maximum energy product, (BH)max. Samples with composite structure contained thermoplastic polymer and hardmagnetics powders. The flaky and spheroidal powder made from magnetic isotropic alloy Nd-Fe-B (Magnequench International USA) were used. As polymer matrix, the high impact polystyrene (DWORY S.A.) was used. Composites were made by the solvent method using toluene. Variable filling ratio of the flaky (40÷54%) and spheroidal (40÷64%) powder was used. Modernized injection moulding machine Arburg C4/b were apply to manufacture of samples. The temperature of feedstock during injection was 160, 200 and 240ºC. The pressure of injection was 80, 110 and 140 MPa. The commercial flaky and spheroidal powders are shown. The influence of flaky and spheroidal powders content on maximum energy product of injection moulded dielectromagnets in constant temperature (200ºC) and constant pressure (110 MPa) is shown. It was stated that the higher filling ratio (Vp) of the composites by the powder the higher (BH)max and the better are dielectromagnets. For the same value of Vp, composites filled by flaky powder have higher (BH)max. It was coused by better properties of flaky powder. But using spheroidal powder higher filling content Vp is possible, so magnetic properties may be compare to properties reached at maximum Vp for flaky powder. The influence the filling ratio with both kind of powder used for preparing the feedstocks on (BH)max of injection moulded dielectromagnets at constant pressure of 110 MPa and temperature of 160, 200 and 240ºC were shown. The investigation results of influence the volume fraction of magnetic powder in composites with both kind of powder on (BH)max injection in constant temperature of 200ºC and pressure of 80, 110 and 140 MPa were presented. The analysis of the received results showed, that the significant influence on the (BH)max had the kind of the powder used for prepared samples. The influence of the injection moulding parameters on (BH)max received dielectromagnets are limited.