METHOD OF CREATING AN INTERIOR METAL FLOW OPENING IN A METAL SHEET DURING A FORMING OPERATION

Abstract

Segment openings are formed in a metal sheet separated by uncut sections at a first processing station, which define an inner blank portion of the metal flow opening. At a second processing station, the uncut sections and the inner blank portion initially transfer stress around the segment openings and across the interior flow opening during a forming operation. During the forming operation, a protrusion of one mold member contacts a first side of the inner blank portion of the interior flow opening. In addition, another mold member is contact the opposite side of the metal sheet so that the mold members cooperate to separate all but one of the uncut sections by which the inner blank portion remains attached to the metal sheet. In this way, the interior metal flow opening is completed without piercing the metal sheet at the second processing station during the forming operation.

Claims

1. A non-piercing method of creating an interior metal flow opening in a metal sheet during a forming operation to facilitate outward metal flow from the metal flow opening during the forming operation, the method comprising: at a first processing station, cutting a series of segment openings in the metal sheet separated by uncut sections, which together define an inner blank portion of the metal flow opening; transferring a portion of the metal sheet having the segment openings and the uncut sections to a second processing station; at the second processing station, forming the portion of the metal sheet by relative movement of two mold members; during an initial phase of the forming at the second processing station, the uncut sections and the inner blank portion transferring stress around the segment openings and across the interior flow opening; during a subsequent phase of the forming at the second processing station, causing a protrusion of a first of the mold members to contact a first side of the metal sheet at the inner blank portion of the interior flow opening and a second of the mold members to contact a second, opposite side of the metal sheet to separate all but one of the uncut sections by which the inner blank portion remains attached to the metal sheet; wherein the interior metal flow opening is completed without piercing the metal sheet at the second processing station during the forming operation.

2. The non-piercing method of claim 1, wherein the cutting the series of segment openings at the first processing station comprises laser cutting the series of segment openings.

3. The non-piercing method of claim 2, wherein the laser forming is part of a laser blanking operation at the first processing station.

4. The non-piercing method of claim 1, wherein the cutting the series of segment openings at the first processing station comprises die cutting the series of segment openings.

5. The non-piercing method of claim 4, wherein the die cutting is part of a die blanking operation at the first processing station.

6. The non-piercing method of claim 1, wherein the causing the protrusion of the first of the mold members to contact the first side of the metal sheet comprises a punch moving outwardly relative to the first of the mold members to contact a first side of the metal sheet.

7. The non-piercing method of claim 1, wherein the protrusion of the first of the mold members and the second mold member cooperate to separate the metal sheet along the uncut sections by tearing along the uncut sections.

8. The non-piercing method of claim 1, wherein the protrusion of the first of the mold members and the second mold member cooperate to separate the metal sheet along the uncut sections by cutting along the uncut sections.

9. The non-piercing method of claim 1, further comprising coating the protrusion with a diamond-like carbon (DLC) coating.

10. The non-piercing method of claim 1, wherein the metal sheet is an aluminum or steel metal sheet.

11. The non-piercing method of claim 1, wherein several series of segment openings separated by uncut sections are formed in the metal sheet at the first processing station, and a corresponding number of interior metal flow openings are completed in the metal sheet during the forming operation at the second processing station.

12. The non-piercing method of claim 11, wherein the corresponding number of interior metal flow openings are completed in the metal sheet at different times during the forming operation at the second processing station.

Description

DRAWINGS

[0017] The present invention will become more fully understood from the detailed description and the accompanying drawings.

[0018] FIGS. 1A and 1B are simplified cross-sectional views related to a prior art pierce-lancing method of creating an interior metal flow opening in a metal sheet during a forming operation.

[0019] FIG. 2 are simplified cross-sectional views of a first and a second processing station related to an example method of creating an interior metal flow opening in a metal sheet during a forming operation in accordance with the present disclosure.

[0020] FIG. 3 is a simplified top plan view of a portion of a metal sheet in the process between the first and second processing stations of FIG. 2.

[0021] FIGS. 4A and 4B are simplified cross-sectional views related to aspects of the example method occurring at the second processing station of FIG. 2.

DETAILED DESCRIPTION

[0022] Further areas of applicability will become apparent from the description, claims and drawings, wherein like reference numerals refer to like features throughout the several views of the drawings. It should be understood that the detailed description, including disclosed embodiments and drawings referenced therein are merely exemplary in nature, intended for purposes of illustration only, and are not intended to limit the scope of the present disclosure.

[0023] With reference to FIGS. 2-4B, one example of a non-piercing method of creating an interior metal flow opening 32 during a forming operation in a metal sheet 20 to thereafter facilitate outward metal flow from the metal flow opening 32 during the forming operation is described below. In this example the metal sheet is an aluminum metal sheet 20. Alternatively, the metal sheet is an steel metal sheet 20. This example process includes cutting a series of segment openings 24 in the metal sheet 20 separated by uncut sections 26 at a first processing station. Together, the segment openings 24 and uncut sections 26 define an inner blank portion 30 of the interior metal flow opening 32 at the first processing station 28 as well as the boundaries of a future interior metal flow opening 32. The segment openings 24 formed at the first processing station 28 operate as separation initiating openings 24 from which subsequent cutting, tearing or other separation action along the uncut sections 26 can be initiated to create the interior flow opening 32.

[0024] The first processing station 28 is a die blanking station that includes die components 36, 38 that operate to die cut the series of segment openings 24 in the metal sheet 20 as part of a die blanking operation. Alternatively, the first processing station 28 is a laser blanking station that includes laser cutting components 36, 38 that operate to laser cut the series of segment openings 24 as part of a laser blanking operation.

[0025] The portion of the metal sheet 20 having the segment openings 24 and the uncut sections 26 is transferred from the first processing station 28 to a second processing station 34. The second processing station 34 is a drawing or forming station. At the second processing station, the portion of the metal sheet 20 by relative movement of two mold members 36, 38 undergoes a forming operation. During an initial phase of the forming operation at the second processing station 34, the uncut sections 26 and inner blank portion 30 operate to transfer stress around the segment openings 24 and across the interior flow opening 32. Thus, outward metal flow from the interior flow opening 32 is restricted during this initial forming phase at the second processing station.

[0026] During a subsequent phase of the forming at the second processing station 34, a protrusion 40 of one of the mold members 44 contacts a first side of the metal sheet 20 at the inner blank portion 30 of the interior flow opening 32. The other mold member 42 contacts the opposite, second side of the metal sheet 20 outside the inner blank portion 30 to separate all but one of the uncut sections 26. In this way, the inner blank portion 30 remains attached to the metal sheet 20 with the interior flow opening 32 being fully formed or completed. In addition, the interior metal flow opening 32 achieves this completion without piercing the metal sheet during the forming operation at the second processing station.

[0027] In this example, the protrusion 40 of the mold member 44 is a punch that is movable outwardly relative to the mold member 44 to contact the metal sheet 20. Alternatively, the protrusion 40 of the mold member 44 is a part of the mold member 44 that is brought into contact with the metal sheet 20 solely due to relative movement of the mold members 44, 42 toward each other during the forming operation.

[0028] As shown in FIG. 2, the example includes the mold member 44 having several protrusions 40 so that several interior metal flow openings 32 are formed in the metal sheet 20 during the forming operation at the second processing station 34. For example, 2, 3, 4, 5, or more interior metal flow openings 32 are formed in the metal sheet 20 during the forming operation at the second processing station 34. Alternatively, a single interior metal flow opening 32 is formed in the metal sheet 20 during the forming operation at the second processing station 34.

[0029] As shown in FIG. 2, the different protrusions 40 are operable to engage the metal sheet 20 at different times during the forming operation so that the interior metal flow openings 32 are formed in the metal sheet 20 at different times during the forming operation at the second processing station 34. Thus, the initiation of outward metal flow from the different interior metal flow openings 32 occurs at different times during the forming operation at the second processing station 34. Alternatively, the different protrusions 40 operate to engage the metal sheet 20 at the same time to simultaneously form all of the interior metal flow openings 32 in the metal sheet 20.

[0030] As shown in FIG. 3, the uncut sections 26 of an interior metal flow opening 32 all have the same length, except for the uncut section 26 that remains uncut after the interior metal flow opening 32 is completed. Alternatively, the uncut sections 26 of an interior metal flow opening 32 have different lengths so that the order in which separation occurs along the different uncut sections 26 is controlled. Additionally or alternatively, each of several interior metal flow openings 32 in a metal sheet 20 have uniform length uncut sections 26 as noted above, but this uniform length for each interior metal flow openings 32 is different so that the different interior metal flow openings 32 are formed in the metal sheet 20 at different times during the forming operation at the second processing station 34.

[0031] As shown in FIGS. 4A and 4B, the protrusion 40 of the mold member 44 and the mold member 42 contact the opposite sides of the metal sheet in a way that they cooperate to separate the metal sheet 20 along the uncut sections 26 by tearing along the uncut sections 26. Alternatively, the protrusion 40 of the mold member 44 and the mold member 42 contact the opposite sides of the metal sheet in a way that they cooperate to separate the metal sheet 20 along the uncut sections 26 by cutting along the uncut sections 26.

[0032] Potential metal debris is reduced in view of the fact that the protrusions 40 of the example process have a flat, rather than a pointed, engagement surface with the metal sheet 20. A diamond-like carbon (DLC) coating can be applied to the protrusions 40 to also reduce potential debris from friction between the protrusion 40 and the metal sheet 20. Such DLC coatings typically include combinations of carbon and tungsten or carbon, tungsten and chromium nitride. Examples of DLC coatings are sold by IHI Ionbond AG under the tradename Tetrabond. Additional information about DLC coatings is provided in a presentation entitled Wear and Galling Behavior of Coated Tools Used in Pierce Punching of Automotive Aluminum Sheet by Shafiei et al. delivered at the International Deep-Drawing Research Group in June of 2018.

[0033] As used herein, non-piercing and without piercing means without having to simultaneously initiate an opening through the metal sheet in order to separate different portions of the metal sheet from each other. In other words, there is at least one pre-existing opening through the sheet metal from which separation along the metal sheet is initiated.

[0034] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.