STAMPING AND WELDING METHOD AND APPARATUS FOR FORMING A HOLLOW OR TUBULAR MEMBER WITH HIGH TOLERANCES
A method of forming a hollow metal member may include stamping a metal blank to form half shell pieces that are configured to be approximately a half of a hollow metal member and stamping a another metal blank to form a half shell piece that is configured to be approximately the other half of the hollow metal member. The half shell pieces may be aligned to place the edges of the first and second half shell pieces in abutting contact. The half shell pieces may be welded together along seams that are defined at the abutting edges of the first and second half shell pieces. The attached half shell pieces may then be compacted to form the hollow metal member with reduced residual deformation from stamping and welding the half shell pieces.
This application claims benefit and priority under 35 U.S.C. § 119(e) of U.S. provisional application Ser. No. 62/635,220, filed Feb. 26, 2018, which is hereby incorporated herein by reference in its entirety.
TECHNICAL FIELDThis disclosure generally relates to forming methods and processes for hollow or tubular members and, more particularly, to stamping and welding processes for forming hollow or tubular members from metal sheet blanks.
BACKGROUNDMetal tubular members that are formed with a stamping process commonly provide half shells that, after striking, have a springback or residual elastic deformation that results in an imprecise final shape of the stamped half shells. One way that this imprecise final shape of the half shells may be accounted for in the forming a tubular member is to join the half shells together with a lap joint or other form of overlapping seam. These seams commonly provide inaccuracies that are difficult to control for continuously or repetitively forming a precisely shaped part or piece. Another known way to address the issue of springback in half shells is to shape a flange region of the blank and perform at least two strikes on a blank for a deep draw into the blank to avoid elastic deformation, whereby the flanges can be trimmed in a shear die, such as described in U.S. Pat. No. 8,296,922. However, upon welding together abutting edges of the resulting half shells, heat induced deformation may be provided at the seams, especially on thinner metals, so as to create inconsistencies and inaccuracies in the final shape of the part.
SUMMARYThe present disclosure provides a process for forming a hollow metal member or part that involves compacting or re-striking attached shell blanks to form the hollow metal member in a final shape that reduces residual deformation from intermediate stamping and welding processes. There may be residual deformation when forming shell pieces that are stamped from metal blanks, such as metal sheets, where the shell pieces may be configured to be approximately a half of a hollow metal member. Two shell pieces may be aligned to place the edges of the first and second shell pieces in abutting contact for welding the pieces together along the edge abutment seams. There may also be residual deformation or inaccuracies in the attached shell pieces from the welding process. Thus, the attached shell pieces may be compacted, such as at a compacting station, to form the hollow metal member with reduced residual deformation from stamping and welding the shell pieces.
According to one aspect of the present disclosure, a method of forming a hollow metal part includes stamping a first metal blank to form a first shell piece that is configured to be a portion of a desired hollow metal part and stamping a second metal blank to form a second shell piece that is configured to be a remaining portion of the desired hollow metal part. The first and second shell pieces are aligned to place the edges of the first and second shell pieces in abutting contact. The first and second shell pieces are welded together along seams that are defined at the abutting edges of the first and second shell pieces to provide a non-conforming hollow part with residual deformation from stamping and welding the first and second shell pieces. The non-conforming hollow part is then compacted in a die assembly to reduce the residual deformation and to form the desired hollow metal part. Further, the first and second shell pieces may be formed to have an oversized outside profile, such as at least 1 percent greater than a desired outside profile, so that compacting the attached shell pieces reduces the outside profile to the desired outside profile.
According to another aspect of the present disclosure, an apparatus for forming a hollow metal part may provide a stamping station that is configured to stamp at least one metal sheet blank to form first and second shell pieces that are configured to mate together to form a hollow metal part. A welding station may have a fixture configured to align the first and second shell pieces with edges of the first and second shell pieces in abutting contact. Also, the welding station has a welder that is configured to weld the first and second shell pieces together along seams defined at the abutting edges. The welding station forms the hollow metal part with a non-conforming shape due to residual deformation from stamping and welding the first and second shell pieces. A compacting station has at least two die pieces that together are configured to engage around an outside profile of the hollow metal part and apply inward pressure to form the hollow metal part with a desired shape. Optionally, the compacting station may include an internal mandrel that is disposed at a hollow area enclosed by the attached half shell pieces during the compacting of the attached shell pieces.
According to yet another aspect of the present disclosure, a hollow metal part that is formed from two half shell stampings includes an outer wall that extends around a hollow interior area of the metal part and spans between a first end opening and a second end opening of the metal part. A section of the outer wall between the first and second end openings includes a curvature that offsets the first end opening relative to the second end opening. A pair of weld seams extend along opposing portions of the outer wall and between the first and second end openings. The pair of weld seams define an attachment interface of abutting edges of shell stampings that form hollow metal part. The outer wall has a desired shape with a consistent profile that is formed from a finishing compacting press, which reduces residual deformation at the pair of weld seams, such as a result of stamping and welding the shell pieces.
These and other objects, advantages, purposes, and features of the present disclosure will become apparent upon review of the following specification in conjunction with the drawings.
Referring now to the drawings and the illustrative embodiments depicted therein, a method and apparatus is provided for forming a tubular or hollow part or member that is made of metal. The process for forming the hollow metal member 10 (
A stamping station may be configured to stamp metal sheet blanks 14 to form half shell pieces that are configured to be approximately a half of a hollow metal member 10. As shown in
As another example of a process to form a half shell blank, as shown in
As shown in
The welding of the seams may be done with a manual or automated welder at the welding station, such as a laser welder or arc welder or the like. Further, such a welding operation may cause some deformation at the seam 16 between the abutting edges of the half shell blanks or pieces 12a, 12b, such as deformation induced or at least partially attributable to heat of the welding process. This may be more prominent in certain types of metals and with thinner thicknesses of metal pieces, which can create inconsistencies and inaccuracies that are difficult to predict or control. As shown in
To illustrate the combined potential effect of the springback and heat induced deformation,
To provide sufficient material for the compacting station 18 to engage and form the desired part, the half shell pieces 12a, 12b may be formed to have an oversized outside profile that is greater than a desired outside profile of the resulting hollow metal member 10 formed by the compacting station 18 (
Once welded together and compacted to or toward the nominal shape, the half shell pieces 12a, 12b of the hollow metal member 10 together provide an outer wall 48 that extends around the hollow interior area 46 of the metal member 10. The outer wall 48 may have a substantially constant thickness and a generally uninterrupted and continuous outer surface. As shown in
The openings 50a, 50b in the hollow metal member 10, such as shown in
With reference to
As further shown in
As further shown in
The openings 150a, 150b, 150c, such as shown in
There may be residual deformation when forming half shell pieces that are stamped form metal blanks, such as metal sheets, where the half shell pieces are configured to be approximately a half of a hollow metal member. Two half shell pieces may be aligned to place the edges of the first and second half shell pieces in abutting contact for welding the pieces together along the edge abutment seams. There may also be residual deformation or inaccuracies in the attached half shell pieces from the welding process. Thus, the attached half shell pieces may be compacted, such as at a compacting station, to form the hollow metal member with reduced residual deformation from stamping and welding the half shell pieces.
For purposes of this disclosure, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” “inner,” “outer,” and derivatives thereof shall relate to the concept as oriented in
Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law. The disclosure has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.
Claims
1. A method of forming a hollow metal part, said method comprising:
- stamping a first metal blank to form a first shell piece that is configured to be a portion of a desired hollow metal part;
- stamping a second metal blank to form a second shell piece that is configured to be a remaining portion of the desired hollow metal part;
- aligning the first and second shell pieces to place edges of the first and second shell pieces in abutting contact;
- welding the first and second shell pieces together along seams defined at the abutting edges of the first and second shell pieces to provide a non-conforming hollow part with residual deformation from stamping and welding the first and second shell pieces; and
- compacting the non-conforming hollow part in a die assembly to reduce the residual deformation and form the desired hollow metal part.
2. The method of claim 1, wherein the first shell piece is configured to be approximately a half of the desired hollow metal part and the second shell piece is configured to be approximately the other half of the desired hollow metal part.
3. The method of claim 1, wherein the first and second shell pieces are formed to have an oversized outside profile that is greater than an outside profile of the desired hollow metal part.
4. The method of claim 3, wherein the oversized outside profile has a diameter that is at least 1 percent greater than a corresponding diameter the outside profile of the desired hollow metal part.
5. The method of claim 1, wherein the die assembly that compacts the non-conforming hollow part includes at least two die pieces that contact substantially entirely around an outer surface of the non-conforming hollow part.
6. The method of claim 5, wherein an internal mandrel is disposed at a hollow area enclosed by the attached first and second half shell pieces during the compacting of the non-conforming hollow part by the at least two die pieces.
7. The method of claim 1, wherein the desired hollow metal part includes at least one opening that is configured to be press fit with a tubular component.
8. The method of claim 1, wherein the desired hollow metal part includes at least three openings.
9. The method of claim 1, wherein the desired hollow metal part includes a first end opening and a second end opening, and wherein a curved section of the hollow metal part is disposed between the first and second end openings.
10. An apparatus for forming a hollow metal part, said apparatus comprising:
- a stamping station configured to stamp at least one metal sheet blank to form first and second shell pieces that are configured to mate together to form a hollow metal part;
- a welding station having a fixture configured to align the first and second shell pieces with edges of the first and second shell pieces in abutting contact and a welder configured to weld the first and second shell pieces together along seams defined at the abutting edges;
- wherein the welding station forms the hollow metal part with a non-conforming shape due to residual deformation from stamping and welding the first and second shell pieces; and
- a compacting station having at least two die pieces that together are configured to engage around an outside profile of the hollow metal part and apply inward pressure to form the hollow metal part with a desired shape.
11. The apparatus of claim 10, wherein the desired shape of the hollow metal part has a consistent outside profile with reduced residual deformation.
12. The apparatus of claim 11, wherein the first and second shell pieces are formed to have an oversized outside profile that is greater than the consistent outside profile of the desired shape of the hollow metal part.
13. The apparatus of claim 12, wherein the oversized outside profile has a diameter that is at least 1 percent greater than a corresponding diameter the consistent outside profile of the desired shape of the hollow metal part.
14. The apparatus of claim 10, wherein the first shell piece is configured to be approximately a half of the hollow metal part and the second shell piece is configured to be approximately the other half of the hollow metal part.
15. The apparatus of claim 10, wherein the compacting station has an internal mandrel is disposed at a hollow area of the hollow metal part to prevent the inward pressure from collapsing the hollow metal part when forming the desired shape.
16. A hollow metal part formed from two shell stampings, said hollow metal part comprising:
- an outer wall that extends around a hollow interior area of the hollow metal part and spans between a first end opening and a second end opening of the hollow metal part;
- wherein a section of the outer wall between the first and second end openings includes a curvature that offsets the first end opening relative to the second end opening;
- a pair of weld seams extending along opposing portions of the outer wall and between the first and second end openings, wherein the pair of weld seams define an attachment interface of abutting edges of shell stampings; and
- wherein the outer wall has a desired shape comprising a consistent profile that is formed from a finishing compacting press that reduces residual deformation at the pair of weld seams.
17. The hollow metal part of claim 16, wherein outer wall near at least one of the first or second end openings includes a circular shape configured to be press fit with a tubular component.
18. The hollow metal part of claim 16, wherein the outer wall defines a third end opening, and wherein at least one of the pair of weld seams intersect the third end opening.
19. The hollow metal part of claim 16, wherein the shell stampings are formed to have an oversized outside profile with a diameter that is at least 1 percent greater than the consistent profile that is formed from the finishing compacting press.
20. The hollow metal part of claim 19, wherein the shell stampings defined by the weld seams are configured to be approximately a half of the desired shape of the outer wall of the hollow metal part.
Type: Application
Filed: Feb 26, 2019
Publication Date: Aug 29, 2019
Inventors: Robert L. Middleton, JR. (Middleville, MI), Gregory M. Sandborn (Alto, MI)
Application Number: 16/285,601