Method of manufacturing variable vane seal and washer materials
A multi-layer seal and washer that provide a seal between a vane stem and a casing in a turbine engine are disclosed. The seal and washer are fabricated from materials such as Teflon fibers and glass fibers and are impregnated with a polyimide resin. The seal and washer are durable and have a low coefficient of friction.
1. A method for manufacturing a bearing element comprising the steps of:
forming a plurality of layers from a combination of a first material and a second material, wherein a first of the layers includes an exterior surface and an interior surface, the first layer formed from a plurality of materials comprising polytetrafluoroethylene fibers, and at least one of glass fibers and carbon fibers, wherein the exterior surface includes a higher concentration of polytetrafluoroethylene fibers and the interior surface includes a higher concentration of the at least one of glass fibers and carbon fibers, and wherein a second of the layers is formed against the first layer and is formed from a material comprising at least one of glass fibers and carbon fibers, and wherein a third of the layers includes an exterior surface and an interior surface, the first layer formed from a plurality of materials comprising polytetrafluoroethylene fibers, and at least one of glass fibers and carbon fibers, wherein the exterior surface includes a higher concentration of polytetrafluoroethylene fibers and the interior surface includes a higher concentration of the at least one of glass fibers and carbon fibers;
forming the bearing element from the plurality of layers, wherein each layer is formed from at least one of weaving materials and braiding materials;
plasma etching each of the bearing element plurality of layers to facilitate enhancing bonding between adjacent layers; and
impregnating each of the bearing element plurality of layers with a polyimide resin comprising polytetrafluoroethylene powder.
2. A method in accordance with claim 1 wherein said step of forming the plurality of layers further comprises the steps of:
forming the first layer from a woven mat of the first material;
forming the second layer from a woven mat of the second material; and
forming the third layer from a woven mat of the first material.
3. A method in accordance with claim 1 wherein said step of forming the plurality of layers further comprises the steps of:
forming the first layer from a braid of the first material;
forming the second layer from a braid of the second material; and
forming the third layer from a braid of the first material.
4. A method in accordance with claim 1 wherein:
the first layer comprises polytetrafluoroethylene fibers and glass fibers;
the second layer comprises glass fibers;
the third layer comprises polytetrafluoroethylene fibers and glass fibers; and
the glass fibers are coated with an epoxy sizing.
5. A method in accordance with claim 4 wherein carbon fibers are substituted for the glass fibers.
6. A method in accordance with claim 4 wherein quartz fibers are substituted for the glass fibers.
7. A method in accordance with claim 4 wherein a silane sizing is substituted for the epoxy sizing.