Method of manufacturing ferromagnetic toroids used in ferrite phase shifters
AssigneeNorthrop Grumman Corporation
InventorsCynthia W. Berry, Deborah P. Partlow, Alex E. Bailey
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Abstract
A fabrication process for ferrite toroids which utilizes ferrite ceramic tape having an improved elongation characteristic. The process utilizes a set of rigid mandrels which are employed in the final lamination to support the rectangular cross section of the internal cavity of a respective ferrite tube, thereby reducing stress concentration and permitting the highest lamination pressure to be used in the final step. The mandrels are removed prior to panel densification. The tape and mandrels operate together to minimize cracks and pores in the toroids and provide an added advantage of maintaining high tolerances in the internal cavity dimensions as well as the cavity-to-cavity alignment.
Claims20
A method of forming a ferrite toroid, comprising the steps of:
- (a) forming a laminated center section of a ferrite tape having a predetermined elongation characteristic;
- (b) forming parallel elongated slots in the laminated center section;
- (c) locating the laminated center section on top of a laminated bottom section of ferrite tape;
- (d) laminating the center and bottom section in a second lamination step;
- (e) cutting off an end portion of the center section and exposing the ends of the slots in the center section;
- (f) placing a set of mandrels in the slots for reducing stress concentration in the ferrite tape;
- (g) placing a laminated top section of ferrite tape on top of the center section with the mandrels in place;
- (h) laminating the top, center and bottom section in a third lamination step to form a composite toroid structure;
- (i) removing the mandrels from the slots;
- (j) densifying the composite toroid structure;
- and
- (k) cutting the composite toroid structure to a selected size.
A method of forming a ferrite toroid, comprising the steps of:
- (a) laying up plural layers of ferrite tape on a laminate to form the top, center and bottom sections separated by respective layers of polyester film and including a layer of polyester film on top of the top section and a layer of polyester film between the bottom section and the laminate, said layers of ferrite tape having an elongation characteristic of between about 15% and 25%;
- (b) simultaneously forming matching tooling holes in the respective layers of polyester film and the laminated layers of ferrite tape of the top, center and bottom sections;
- (c) separating the laminated sections;
- (d) forming parallel elongated slots in the laminated center section;
- (e) locating the laminated center section on top of the laminated bottom section of ferrite tape;
- (f) laminating the center and bottom section in a second lamination step;
- (g) cutting off an end portion of the center section and exposing the ends of the slots in the center section;
- (h) placing a set of elongated mandrels in the slots;
- (i) placing the laminated top section of ferrite tape on top of the center section with the mandrels in place;
- (j) laminating the top, center and bottom section in a third lamination step to form a composite toroid structure;
- (k) removing the mandrels from the slots;
- (1) densifying the composite toroid structure by firing;
- and
- (m) dicing the composite toroid structure into a desired slab size.
Dependencies are inferred from the claim text.