Grain orientation control through hot pressing techniques

Abstract

Systems and methods for electrical component, e.g., brush, manufacture are provided that control grain orientation. The systems and methods utilize hot pressing techniques to enhance the properties and functionalities of the electrical components / brushes. An intermediate work product characterized by a grain orientation is initially formed through a conventional pressing technique. The conventionally-pressed intermediates are positioned within a cavity / die with the grain orientation in a predetermined orientation relative to the hot press force to be applied thereto. The hot pressed final product exhibits superior resistivity, strength and apparent density / durability. Surface features may be formed on the face(s) of the final work product during the hot pressing step that cannot be achieved in conventional processing techniques. Multi-layered assemblies are provided that may be cross-linked or inter-bonded along an interface therebetween. Advantageous articles of manufacture, e.g., brushes and brush assemblies, are also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application is a continuation-in-part application that claims the benefit of a co-pending, commonly assigned non-provisional patent application entitled “Grain Orientation Control Through Hot Pressing Techniques,” which was filed on Sep. 1, 2006 and assigned Ser. No. 11 / 515,467. The present application is directed to non-elected subject matter in the foregoing non-provisional application and is functionally a divisional application with respect to such non-provisional application, the subject matter of which is incorporated herein by reference.BACKGROUND [0002] 1. Technical Field [0003] The present disclosure is directed to systems and methods for brush manufacture and, more particularly, to systems and methods that control grain orientation in components, assemblies and other articles of manufacture. Exemplary systems and methods disclosed herein utilize hot pressing techniques to enhance the properties and / or functionalitie...

AI Technical Summary

Benefits of technology

[0009] According to exemplary embodiments of the present disclosure, a powder mixture is initially pressed in a conventional manner to form an intermediate work product. The conventional pressing step establishes a grain orientation within the intermediate work product that is perpendicular to the direction of the compression forces applied thereto during the conventional pressing process. Thereafter, the conventionally-pressed intermediate work product is further processed by a hot pressing technique, wherein the initial grain orientation of the intermediate work product is maintained while compression forces are applied in the hot pressing step. Through the hot pressing step, the density of the work piece is further increased, thereby enhancing the durability thereof, e.g., when employed as a brush or other electric component. Superior functional properties, such as specific resistivity and strength, are also imparted to the work piece through the disclosed hot pressing technique.

[0013] In addition to the advantageous fabrication techniques disclosed herein, the present disclosure is directed to advantageous electrical components, e.g., brushes and brush assemblies, that are formed, in whole or in part based on the disclosed fabrication techniques. Thus, the present disclosure provides brushes and brush assemblies that define a first axis, wherein the internal grains of the brush / brush assembly are substantially aligned with the first axis and wherein molded surface features are formed on at least one face that is traversed by such first axis. In a further exemplary embodiment of the present disclosure, a brush assembly is provided that is characterized by a plurality of distinct conventionally-pressed layers, wherein the layers are bonded to each other and wherein the grains of the individual layers can be controlled independent of each other. Bonding between respective layers may be facilitated by inter-bonding and / or cross-linking between constituents of the respective layers, e.g., cross-linking of resins present in each of the respective layers.

Problems solved by technology

Despite efforts to date, techniques for fabrication of brushes imposes significant limitations on the design, geometry, structural features and properties / performance.

Moreover, brushes and brush assemblies fabricated according to conventional processing techniques / methodologies are characterized by durability issues based, at least in part, on density limitations associated with conventional fabrication techniques.

Indeed, the disclosed fabrication techniques and methods may be employed to form press-to-fit brush members that are not achievable using conventional compression molding techniques.

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