Patent Grant
11865603
The present disclosure relates to a method of reducing tool marks when incrementally forming a workpiece.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Incremental forming is a manufacturing technique that is used to form a workpiece without associated forming dies. Generally, a workpiece is formed incrementally by two opposing forming tools, as described for example in U.S. Pat. Nos. 8,302,442, 8,322,176, 8,733,143, and 8,783,078, which are commonly assigned with the present application and the contents of which are incorporated herein by reference in their entirety.
The opposed forming tools often generate hard marks along the surfaces of the workpieces being formed, which can result in insufficient surface quality. This surface quality issue of incremental forming is addressed by the present disclosure.
In one form of the present disclosure, a device for use in incrementally forming a plurality of workpieces includes a frame configured to receive a workpiece, at least one clamp configured to secure the workpiece to the frame, a first sacrificial material layer configured to be secured to at least one surface of the workpiece, and a first forming tool configured to impart a first force directly to the first sacrificial material layer and incrementally form the workpiece to a desired geometry based on a tool path of the first forming tool. In some variations, the frame, the at least one clamp, the first sacrificial material layer, and the first forming tool are configured to impart a first force directly to the first sacrificial material layer secured to at least one surface of a first workpiece with the first forming tool and incrementally form the first workpiece to a desired geometry based on a tool path of the first forming tool, for the first sacrificial material layer to be removed from the incrementally formed first workpiece and secured it to at least one surface of a second workpiece, and to impart a second force directly to the first sacrificial material layer with the first forming tool to incrementally form the second workpiece to another desired geometry based on another tool path of the first forming tool.
In some variations, the first sacrificial material layer is secured around a periphery of the first workpiece and around a periphery of the second workpiece.
In at least one variation, the device further includes at least one elastomeric material disposed between the first workpiece and the first sacrificial material layer.
In some variations, the first sacrificial material layer is a protective film.
In at least one variation, the first sacrificial material layer is metal sheet. In such variations, the metal sheet can be a low carbon steel sheet having a thickness between 0.1 mm and 1.0 mm.
In some variations, the device further includes a second sacrificial material layer secured to the frame and configured to conform to an opposite working surface of the workpiece, wherein the first and second sacrificial material layers form a space therebetween to receive the workpiece. And in at least one variations, the device further includes at least one elastomeric material disposed between at least one of the first workpiece and the first sacrificial material layer, and the first workpiece and the second sacrificial material layer. In some variations, the second sacrificial material layer is secured around a periphery of the first workpiece and around a periphery of the second workpiece, and a second forming tool opposed to the first forming tool is included. In such variations, the second forming tool is configured to impart a third force directly to the second sacrificial material layer. For example, in some variations, the second forming tool is configured to impart the third force directly to the second sacrificial material layer when the first forming tool imparts the first force directly to the first sacrificial material layer. Also, the first sacrificial material layer and the second sacrificial material layer can be each a metal sheet, for example, a low carbon steel sheet having a thickness between 0.1 mm and 1.0 mm.
In another form of the present disclosure, a device for use in incrementally forming a plurality of workpieces includes a frame configured to receive a workpiece, at least one clamp configured to secure the workpiece to the frame, a first sacrificial material layer configured to be secured to at least one surface of the workpiece and a second sacrificial material layer configured to be secured to an opposite surface of the workpiece, a first forming tool configured to impart a first force directly to the first sacrificial material layer and incrementally form the workpiece to a desired geometry based on a tool path of the first forming tool, and a second forming tool configured to impart a third force directly to the second sacrificial material layer. The frame, the at least one clamp, the first and second sacrificial material layers, and the first and second forming tools are configured to impart a first force directly to the first sacrificial material layer secured to at least one surface of a first workpiece with the first forming tool and incrementally form the first workpiece to a desired geometry based on a tool path of the first forming tool, remove the first sacrificial material layer from the incrementally formed first workpiece and secure it to at least one surface of a second workpiece, and impart a second force directly to the first sacrificial material layer with the first forming tool to incrementally form the second workpiece to another desired geometry based on another tool path of the first forming tool.
In some variations, the first sacrificial material layer and the second sacrificial material layer are secured around a periphery of the first workpiece and around a periphery of the second workpiece.
In at least one variation, the device further includes at least one elastomeric material disposed between at least one of the first workpiece and the first sacrificial material layer, and the first workpiece and the second sacrificial material layer.
In still another form of the present disclosure, a device for use in incrementally forming a plurality of workpieces includes a frame configured to receive a workpiece, a plurality of clamps configured to secure the workpiece to the frame, a first sacrificial material layer configured to be secured to at least one surface of the workpiece and a second sacrificial material layer configured to be secured to an opposite surface of the workpiece, at least one elastomeric material disposed between at least one of the first sacrificial material layer and the workpiece, and the second sacrificial material layer and the workpiece, a first forming tool configured to impart a first force directly to the first sacrificial material layer and incrementally form the workpiece to a desired geometry based on a tool path of the first forming tool, and a second forming tool configured to impart a third force directly to the second sacrificial material layer. The frame, the at least one clamp, the first and second sacrificial material layers, and the first and second forming tools are configured to impart a first force directly to the first sacrificial material layer secured to at least one surface of a first workpiece with the first forming tool and incrementally form the first workpiece to a desired geometry based on a tool path of the first forming tool, have the first and second sacrificial material layers removed from the incrementally formed first workpiece and secured to opposing surfaces of a second workpiece, and impart a second force directly to the first sacrificial material layer with the first forming tool to incrementally form the second workpiece to another desired geometry based on another tool path of the first forming tool.
In some variations, at least one of the first sacrificial material layer and the second sacrificial material layer a low carbon steel sheet having a thickness between 0.1 mm and 1.0 mm.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring to
Generally, in incremental forming, the workpiece 12 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 32 and 32′ along and against one or more surfaces 14 of the workpiece 12. 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 a sensor such as a load cell. Thus, incremental forming may occur in increments as at least one tool (e.g., 32, 32′) is moved and without removing material from the workpiece 12. More details of such a system 10 are described in U.S. Pat. Nos. 8,302,442, 8,322,176, 8,733,143, and 8,783,078 which have been incorporated herein by reference in their entirety.
The system 10 may include a plurality of components that facilitate forming of the workpiece 12, such as a frame 20, a plurality of clamps 30 disposed around a periphery of the workpiece 12, the forming tools 32 and 32′, at least one sacrificial material layer 70, and optionally at least one elastomeric material 72, among other layers as described in greater detail below. The forming tools 32 and 32′ should be construed as being generally synonymous with first and second forming tools throughout this specification.
The frame 20 and the clamps 30 are provided to support the workpiece 12. The frame 20 in this form is configured as a “picture frame” that at least partially defines an opening (partially shown in
The clamps 30 are configured to engage and exert a clamping or holding force on the workpiece 12 so that the periphery of the workpiece 12 remains stationary during incremental forming. The clamps 30 may be provided along multiple sides of the frame 20 and may have any suitable configuration and associated geometry for holding the workpiece 12 stationary. For instance, the clamps 30 may be manually, pneumatically, hydraulically, and/or electrically actuated. Moreover, the clamps 30 may be configured to provide a fixed or adjustable amount of force upon the workpiece 12. In still another form, mechanical fasteners (not shown) may be used instead of clamps 30, among other devices for securing the workpiece 12 during incremental forming.
First and second forming tools 32, 32′ have multiple degrees of freedom and are positioned according to the design specifications of the workpiece 12. The forming tools 32, 32′ are configured to move along a plurality of axes, such as axes extending in different orthogonal directions like X, Y and Z axes. Note the forming tools 32, 32′ may be positioned according to any coordinate system including Cartesian (X, Y, Z), cylindrical (ρ, φ, z), and spherical (ρ, θ,φ). The forming tools 32, 32′ may be disposed on a spindle and may be configured to rotate about an associated axis of rotation in one or more forms of the present disclosure.
The forming tools 32, 32′ impart forces to incrementally 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. For brevity, ball-shaped tools are depicted in the drawings and associated text. As the forming tools 32, 32′ incrementally form the workpiece 12, tool marks are sometimes left upon the surface of the workpiece 12 as shown in
As shown in
The sacrificial layer 70 should have a low coefficient of friction to reduce friction between the forming tools 32, 32′ and the sacrificial layer 70. The sacrificial layer 70 should have sufficient stiffness and rigidity to resist buckling due to friction. The sacrificial layer 70 may comprise more than one layer, as set forth in greater detail below, as it may be difficult to obtain the required combination of properties from only one sacrificial layer 70. The sacrificial layer 70 is “sacrificial” in that the sacrificial layer 70 is not incorporated into the formed workpiece 12 and is discarded or recycled after the workpiece 12 is formed. If recycled, the sacrificial layer 70 may be reused numerous times to incrementally form more than one workpiece 12 depending on the rigors of the incremental forming process to form a given workpiece 12. Sacrificial layer 70 has adequate thickness to redistribute force or pressure to the workpiece 12. However, as the thickness of the sacrificial layer 70 increases, the level of protection for the workpiece 12 increases while forming becomes more difficult and less precise.
In various forms, the sacrificial layer 70 is secured to at least one surface 14 of the workpiece 12, a plurality of sacrificial layers 70 are secured to at least one surface 14 of the workpiece 12, and a plurality of sacrificial layers 70 are secured to opposed sides of the workpiece 12, where the sacrificial layers 70 in the plurality of sacrificial layers 70 may have different thicknesses and may be different materials. For example, in one form, the sacrificial layer 70 is a low carbon steel having a thickness between 0.1 mm and 1.0 mm for a workpiece 12 thickness of between 0.5 mm and 4 mm.
In one variation as shown best in
The elastomeric materials 72 and 72′ are similarly operable to transmit forces from the forming tools 32, 32′, through the first and second sacrificial material layers 70, 70′, and to the workpiece 12. The elastomeric material 72 is secured to at least one surface of the workpiece 12, and thus the illustration of the second elastomeric material 72′ is merely exemplary. Similarly, the sacrificial layer 70 and the elastomeric material 72 may be used on only one side of the workpiece 12 while remaining within the scope of the present disclosure. Further, it should be understood that any number of materials and layers may be employed according to the specific workpiece 12 material and geometry being incrementally formed while remaining within the scope of the present disclosure.
Because forming tools 32, 32′ impart forces to the sacrificial layers 70/70′ and the elastomeric materials 72/72′, the formed workpiece 12 has an improved surface quality, which is more suitable for certain applications. The elastomeric material 72 may comprise more than one layer as it may be difficult to obtain the required combination of properties from one elastomeric material 72. The elastomeric material 72 should be compressible and have a Young's modulus sufficient to redistribute the compressive force and the associated contact pressure to a larger area. Elastomeric material 72 has adequate thickness to redistribute force or pressure from the forming tools 32 and 32′ to the workpiece 12. However, as the thickness of the elastomeric material 72 increases the level of protection for the workpiece 12 increases while forming becomes more difficult and less precise. In various forms, the elastomeric material 72 is secured to at least one surface of the workpiece, a plurality of elastomeric materials 72 are secured to at least one surface of the workpiece, and a plurality of elastomeric materials 72/72′ are secured to opposed surfaces of the workpiece, where the elastomeric material 72 may have different thicknesses, and the plurality of elastic materials may be different materials. For example, in one form, the elastomeric material 72 is a rubber having a thickness between about 0.2 mm and about 5 mm.
Lubricant may be applied to the workpiece 12, the forming tools 32 and 32′, the sacrificial layer 70, and the elastomeric material 72, and combinations thereof, to improve sliding, reduce friction, and reduce shear stresses, among other benefits. Therefore, lubricant is applied to improve the incremental forming of workpiece 12 and its surface quality.
In another form, a polymer material may be used as the sacrificial layer 70, and in another form, a protective film is the sacrificial layer 70. Further, an adhesive (not shown) may be applied to the workpiece 12, the sacrificial layer 70, or the elastomeric material 72 in order to prevent slippage/movement between the workpiece 12, the sacrificial layer 70, and/or the elastomeric material 72. In one form, the adhesive is a low tack pressure sensitive adhesive.
Referring to a
Referring to a
These methods can be carried out in any order of steps and are not limited to those shown herein. Also, the methods are carried out using the various materials and components (e.g., sacrificial material layers, elastomeric materials, lubricant, adhesive) as described herein with reference to
The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.
This application is a divisional of and claims priority to U.S. patent application Ser. No. 15/660,271 filed on Jul. 26, 2017. The disclosure of the above application is incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5151277 | Bernardon | Sep 1992 | A |
| 7997891 | Gallagher | Aug 2011 | B2 |
| 8783078 | Ren | Jul 2014 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20210331228 A1 | Oct 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15660271 | Jul 2017 | US |
| Child | 17372696 | US |
