shifting electromagnetic field the temperature and the microstructure of the casting material near the shot chamber are further controlled and perturbed by at least one high frequency electromagnetic field to minimize the temperature difference or the growth of dendritic microstructure to ensure the efficiency of the electromagnetic fields the shot chamber is made of non magnetic material and its wall thickness is less than three times the penetration depth of the electromagnetic fields the shot chamber is surrounded by at least one solenoid coil a conducting shield and at least one electric motor stator the conducting shield which that only allows the low frequency electromagnetic field to penetrate protects the stator from being over heated by the high frequency electromagnetic field application_number US 29377802 A description the material handling and injection chamber for the novel die casting machine of the preferred embodiment is indicated generally at 10 fig1 the die casting machine 10 includes a shot chamber 12 into which casting material is charged a sleeve 14 heat transfer fluid u201c htf u201d passages 16 which are embedded inside the sleeve 14 a ram 18 and electric motor stators 20 surrounding the chamber sleeve 14 the ram 18 has a frontal face 22 that is directed to.