Patent Application
20120011915
The present invention relates to a method of incrementally forming a workpiece.
In at least one embodiment, a method of incrementally forming a workpiece is provided. The method includes incrementally forming a first monotonic wrap surface in a first direction and incrementally forming a second wrap surface in a second direction disposed opposite the first direction.
In at least one embodiment, a method of incrementally forming a workpiece is provided. The method includes incrementally forming a first monotonic wrap surface in a first direction with respect to an initial workpiece position and incrementally forming a second monotonic wrap surface completely within the first monotonic wrap surface in a second direction disposed opposite the first direction.
In at least one embodiment, a method of incrementally forming a workpiece is provided. The method includes incrementally forming a convex surface on the workpiece and incrementally forming a concave surface within the convex surface. No additional convex surface is formed in any area of the workpiece in which the concave surface is not formed.
a, 4b, 5 and 6 are exemplary side section views of the workpiece undergoing a sequence of incremental forming steps.
Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale, some features may be exaggerated or minimized to show details of particular components. In addition, any or all features from one embodiment may be combined with any other embodiment. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention.
Referring to
The system 10 may be used to incrementally form a workpiece. In incremental forming, a workpiece is formed into a desired configuration by a series of small incremental deformations. The small incremental deformations may be provided by moving one or more tools along or against one or more surfaces of the workpiece. Tool movement may occur along a predetermined or programmed path. In addition, a tool movement path may be adaptively programmed in real-time based on measured feedback, such as from the load cell. Thus, incremental forming may occur in increments as at least one tool is moved and without removing material from the workpiece. More details of such a system 10 are described in U.S. patent application Ser. No. 12/369,336, which is assigned to the assignee of the present application and is hereby incorporated by reference in its entirety. A brief summary of some components of such a system 10 is provided below.
The system 10 may include a plurality of components that facilitate forming of the workpiece 12, such as a fixture assembly 20, a first manipulator 22, a second manipulator 24, and a controller 26.
The fixture assembly 20 may be provided to support the workpiece 12. The fixture assembly 20 may be configured as a frame that at least partially defines an opening 28 (shown in
The fixture assembly 20 may include a plurality of clamps 30 that may be configured to engage and exert force on the workpiece 12. The clamps 30 may be provided along multiple sides of the opening 28 and may have any suitable configuration and actuation mechanism. For instance, the clamps 30 may be manually, pneumatically, hydraulically, or electrically actuated. Moreover, the clamps 30 may be configured to provide a fixed or adjustable amount of force upon the workpiece 12.
First and second positioning devices or manipulators 22, 24 may be provided to position first and second forming tools 32, 32′. The first and second manipulators 22, 24 may have multiple degrees of freedom, such as hexapod manipulators that may have at least six degrees of freedom. The manipulators 22, 24 may be configured to move an associated tool along a plurality of axes, such as axes extending in different orthogonal directions like X, Y and Z axes.
The first and second forming tools 32, 32′ may be received in first and second tool holders 34, 34′, respectively. The first and second tool holders 34, 34′ may be disposed on a spindle and may be configured to rotate about an associated axis of rotation in one or more embodiments.
The forming tools 32, 32′ may impart force to form the workpiece 12 without removing material. The forming tools 32, 32′ may have any suitable geometry, including, but not limited to flat, curved, spherical, or conical shape or combinations thereof.
The one or more controllers 26 or control modules may be provided for controlling operation of the system 10. The controller 26 may be adapted receive CAD or coordinate data and provide computer numerical control (CNC) to form the workpiece 12 to design specifications. In addition, the controller 26 may monitor and control operation of a measurement system that may be provided to monitor dimensional characteristics of the workpiece 12 during the forming process.
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The initial configuration of the workpiece 12 may define a reference configuration or reference plane from which subsequent incremental forming steps may be described or referenced. For instance, for a workpiece 12 having a substantially planar initial configuration a reference plane 40 may be a plane in which the workpiece 12 is disposed. For a non-planar workpiece, a reference configuration or reference plane may be a surface of the workpiece 12 that has not been preformed prior to incremental forming. In addition, a reference configuration may be a mathematically defined surface or datum that does not intersect the workpiece 12. For example, such a reference surface may be a plane or surface that is disposed parallel to but spaced apart from at least a portion of the workpiece 12 when in an initial configuration, such as reference plane 40′. Alternatively, a point, line or other surface may be used as a reference point or datum in various embodiments.
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A wrap surface may be defined in different ways. For instance, a wrap surface may be defined as a surface or contour that is incrementally formed on the workpiece 12 in a monotonic manner or as a monotonic surface. A monotonic wrap surface may be defined in different ways. A first definition of a monotonic wrap surface from a section view perspective as (1) an incrementally formed surface of the workpiece (2) that is formed in a common direction with respect to a reference plane or datum (3) in which a line that connects any two points on the incrementally formed surface that are located at a common distance from the reference plane or datum (4) is located within the surface or surface volume that has been incrementally formed. A second definition of a monotonic wrap surface from a section view perspective may be (1) an incrementally formed surface of workpiece (2) that is formed in a common direction with respect to a reference plane or datum (3) in which the incrementally formed surface is at least partially concave but not convex or at least partially convex but not concave with respect to the reference plane. A third definition of a monotonic wrap surface from a section view perspective may be (1) an incrementally formed surface of workpiece (2) that is formed in a common direction with respect to a reference plane or datum (3) in which the incrementally formed surface is completely concave or completely convex with respect to the reference plane. A wrap surface may satisfy one or more of the previous definitions.
Successive wrap surfaces may be incrementally formed on the workpiece 12. The forming of successive wrap surfaces may be described in terms of different levels or as a parent-child hierarchy in which a child wrap surface may be incrementally formed inside or completely within a parent wrap surface. For example, a parent wrap surface may be incrementally formed, then a child wrap surface may be incrementally formed within the parent wrap surface. If desired, a grandchild wrap surface may then be formed within the child wrap surface and so on. Successive wrap surfaces may be formed in alternating directions. For instance, if a parent wrap surface is at least partially convex, then a child wrap surface may be at least partially convex or vice versa. Similarly, if a child wrap surface is at least partially convex, then a grandchild wrap surface may be at least partially concave or vice versa.
A workpiece 12 may have multiple wrap surfaces at the same level or generation in a parent-child hierarchy. For instance, there may be multiple child-level wrap surfaces formed in a parent wrap surface. Such child-level wrap surfaces and their offspring may be incrementally formed in various sequences. For instance, all child-level wrap surfaces may be formed before forming grandchild-level wrap surfaces (e.g., first and second child-level wrap surfaces may be formed before first and second grandchild-level wrap surfaces, if provided). Another sequence would include forming a complete sequence or branch of wrap surfaces before forming another branch in the parent-child hierarchy. For instance, a first child-level wrap surface and its descendents (if any) may be incrementally formed, then a second child-level wrap surface and it descendents (if any) may be incrementally formed, and so on. The present invention also contemplates that wrap surfaces may be formed using combinations of the above.
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b is another example of a monotonic first wrap surface. In
In
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In
Additional wrap surfaces may be formed subsequent to forming a third wrap surface 70 by continuing to alternate the directions in which the workpiece 12 in incrementally formed. In addition, each subsequent wrap surface may be formed within an immediately preceding wrap surface. For instance, a fourth wrap surface may be formed within the third wrap surface, a fifth wrap surface may be formed within the fourth wrap surface, and so on until the final configuration of the workpiece 12 is obtained. Moreover, in one or more embodiments, no wrap surface may be formed in the second direction in any area of the workpiece 12 that has not already had a wrap surface formed therein in the first direction.
Incremental forming in accordance with the method and wrap surfaces described above may help precisely control execution of tool paths during incremental forming and may help improve the resultant workpiece geometry. As such, the final workpiece geometry may more precisely reflect or match the desired or design intent geometry of the workpiece. In addition, tool paths may be more readily or easily calculated or programmed, thereby improving throughput and manufacturing logistics.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
