CONTOURED AIR VENT HOLES FOR DIES
The present disclosure describes a die for forming sheet metal. The die includes a die body, an outer surface, and a sheet metal facing surface. At least one passage extends through the die body to form an escape route, purging an amount of air trapped in-between the die and a sheet metal during a sheet metal operation. The passage includes an entry port, an exit port, and a bore that connects the entry port to the exit port. Each port has a transition area between its respective surface and the bore. The transition area is configured to be other than a right angle.
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This application relates to the field of sheet metal stamping and, more particularly to air venting systems in dies during sheet metal stamping operations.
In conventional sheet metal stamping operations, with a reciprocating upper die plate moving in relation to a lower die plate, sheet metal is converted to a component of a desired shape. During such stamping operations, the presence of air trapped in-between the die and the sheet metal can cause a deformation in the sheet metal surface, leading to geometrical deviations from the intended shape and design. Such deformations, ranging from surface waviness, or burrs, to even surface distortions, in certain cases, can be observed visually. The resulting inconsistencies in component formations may affect the repeatability of such components in the stamping operation, altering the final quality of the work product.
In current practice, air vent passages are provided in dies to provide relief passages for the trapped air to escape from a sheet metal stamping region lying in-between the die and the sheet metal, during a stamping operation. Such passages are not just configured to purge out the trapped air during a downstroke of an upper die, but also to pull the air into the stamping region during an upstroke to avoid the creation of a vacuum, and to consequently avoid sheet metal deformities associated with such operations.
It may however be noted that during such upstrokes and downstrokes, the passage's design and profile may cause variations and/or restrictions in the flow of air, leading to decreased airflow rates during high output requirements. A design and profile for the passage is thus proposed in disclosure that aims to enhance the airflow rates, enabling better exchange of air between the stamping region and an outside environment.
SUMMARYOne embodiment of the present disclosure discloses a die for forming sheet metal. The die includes a die body, an outer surface, and a sheet metal facing surface. At least one passage extends through the die body, forming an escape route, purging an amount of air trapped in-between the die and a sheet metal during a sheet metal operation. The passage further includes an entry port on the sheet metal facing surface, a bore leading from the entry port, an exit port on the outer surface and extending from the bore, each of the ports having a transition area between its respective surface and the bore, and the transition area being other than a right angle.
Another embodiment of the present disclosure describes an air venting system in a die. The die has a die body with the system including at least one passage configured through the die body to form an escape route, purging an amount of air trapped in-between the die and a sheet metal during a sheet metal operation. The passage defines an entry port, an exit port, and a bore that connects the entry port to the exit port. The entry port and the exit port include a transition area between their respective surface and the bore. The transition area is configured to be other than a right angle.
Certain embodiments of the present disclosure discloses a method of stamping sheet metal, the method includes reciprocating an upper die plate in relation to a lower die plate, with at least the upper die plate having at least one passage configured through the upper die plate's body. The passage is configured to form an escape route for purging an amount of air trapped in-between the upper die plate and a sheet metal during a sheet metal operation. The passage has an entry port, an exit port, and, a bore that connects the entry port and the exit port.
The figures described below set out and illustrate a number of exemplary embodiments of the disclosure. Throughout the drawings, like reference numerals refer to identical or functionally similar elements. The drawings are illustrative in nature and are not drawn to scale.
The following detailed description is made with reference to the figures. Exemplary embodiments are described to illustrate the subject matter of the disclosure, not to limit its scope, which is defined by the appended claims.
OverviewDuring upstrokes and down strokes of a die body relative to a sheet metal, sharp edges of the air vent passages in the die body restrict the airflow, resulting in an inadequate exchange of air between the stamping region and its outside environment.
Inadequate exchange of air because of such sharp edges is observed to cause reduced strokes per minute (SPM) values during stamping operations. Improving the shape and profile of the relief passages enhances airflow. Accordingly, a redefined change in the shape and profile of the relief passage is proposed in the present disclosure.
In general, the present disclosure describes methods and systems for venting air through a die body from a sheet metal stamping region lying in-between the die body and a sheet metal. To this end, the disclosure discloses a passage extending through the die body, enabling air trapped in-between the die body and a sheet metal, to be purged out into an outside environment during a stamping operation. The passage configured with the die body has an entry port and an exit port, along with a bore that connects the ports to each other. Each port is adapted to have a transition area between its respective surface and the bore. The transition area is configured to reduce any restriction on airflow into the passage.
Exemplary EmbodimentsAccordingly, an entry port 118 is configured at a sheet metal facing surface 110, as part of the passage 108c, and an exit port 120, extending from a bore 126, is configured at an outer surface 112, also as part of the passage 108c. The bore 126, leading from the entry port 118, connects the entry port 118 and the exit port 120, forming the passage 108c.
The upper die plate 102 and the lower die plate 104, respectively, can be machined metal blocks. With the lower die plate 104 kept stationery, the upper die plate 102 reciprocates in relation to the lower die plate 104 during stamping operations in a press machine (not shown). The construction, components, and working of such stamping operations are well known in the art and are thus not described further in the disclosure.
The bore 126, as part of the passage 108c, running through the die body 114 may be configured throughout with a constant cross-sectional area, such as circular, as shown in the illustrated embodiment, or elliptical, or polygonal or any other cross-section.
A primary aspect of the prior art depicted in the
According to
With the passage 108c being shaped and designed with a constant cross-sectional area all throughout, a condition such as vena contracta may develop during operational conditions requiring high strokes per minute (SPM). Conditions of high SPM values causing high airflow exchange rates between the stamping region 124 and the outside environment 128, may eventually cause the airflow to develop a cross-sectional area in the passage 108c lesser than the actual cross-sectional area of the bore 126. Vena contracta developed as a result will cause reduced air exchange rates when the passage 108c is configured, shaped, and intended, for a higher air exchange rates. Such a condition may become a limiting factor, and may cause the SPM values to be reduced to an undesirable upper limit, causing decreased product output on a shop floor during higher production requirements.
To exploit the full potential of the passage 108c, a change in the design of the passage 108c is thus proposed in the forthcoming disclosure.
Alternatively, the transition area may be inclined, funnel, or cone shaped, or may be configured to have a larger diameter than the bore 126′. It will be understood that all variations and contours at the entry port 118′ and the exit port 120′ in shape and/or design, configured to vary the quantity of flow of air, are within the scope of the present disclosure.
More particularly, it will be understood that die systems using singular or multiple passages, as described above, would also be covered under the scope of the present disclosure.
It will be understood that during an upstroke of the upper die plate 102, when outside air is pulled into the stamping region 124, the flow of air remains similar since the edges 106′ are similar in design and dimensions.
Machining an external radius at the entry port 118′ and the exit port 120′of the passage 108c′ can be accomplished with a specialized die machining tool. Alternatively, drilling tools can be provided with fixtures that machine rounded edges 106′ while a drilling operation is being carried out. Machining methodologies for similar configurations, along with variations, and alternatives are well known to a person skilled in the art and thus will not be discussed further in the disclosure.
As discussed above, vena contracta may be better understood through
On the other hand,
The specification has set out a number of specific exemplary embodiments, but those skilled in the art will understand that variations in these embodiments will naturally occur in the course of embodying the subject matter of the disclosure in specific implementations and environments. It will further be understood that such variations and others as well, fall within the scope of the disclosure. Neither those possible variations nor the specific examples set above are set out to limit the scope of the disclosure. Rather, the scope of claimed invention is defined solely by the claims set out below.
Claims
1. A die for forming sheet metal, the die comprising:
- a die body, an outer surface, and a sheet metal facing surface;
- at least one passage extending through the die body to form an escape route to purge an amount of air trapped in-between the die and the sheet metal during a sheet metal operation, the passage having: an entry port on the sheet metal facing surface; a bore, having a cross-sectional area, leading from the entry port; an exit port on the outer surface and extending from the bore, each of the ports having a transition area between its respective surface and the bore, the transition area being other than a right angle.
2. The die of claim 1, wherein the transition area is rounded.
3. The die of claim 1, wherein the entry port and the exit port have a larger cross-sectional area than the bore's cross-sectional area.
4. The die of claim 3, wherein the bore's cross-sectional area is configured to be circular.
5. The die of claim 1, wherein the die is a draw die.
6. The die of claim 1, wherein the die is at least one of the following:
- an upper die plate; and
- a lower die plate.
7. An air venting system in a die, the system comprising:
- at least one passage configured through the die to purge air trapped in-between the die and a sheet metal during a stamping operation, the passage defining: an entry port; an exit port; a bore, connecting the entry port to the exit port, the ports having a transition area between their respective surface and the bore, the transition area being other than a right angle.
8. The system of claim 7, wherein the die is a draw die.
9. The system of claim 7, wherein the die comprises at least one of the following:
- an upper die plate; and
- a lower die plate.
10. The system of claim 7, wherein the transition area is rounded.
11. The system of claim 7, wherein the bore includes a circular cross-sectional area.
12. The system of claim 11, wherein the entry port and the exit port have a larger cross-sectional area than the bore's cross-sectional area.
13. A method of stamping sheet metal, the method comprising:
- reciprocating an upper die plate relative to a lower die plate, with at least one passage configured at least through the upper die plate, the passage forming an escape route for purging an amount of air trapped in-between the upper die plate and a sheet metal during a sheet metal operation, the passage having: an entry port; an exit port; a bore, having a cross-sectional area, connecting the entry port and the exit port.
14. The method of claim 13, wherein the entry port and the exit port have a transition area between their respective surface and the bore, the transition area being other than a right angle.
15. The method of claim 14, wherein the transition area is rounded.
16. The method of claim 13, wherein the entry port and the exit port have a larger cross-sectional area than the bore's cross-sectional area.
17. The method of claim 16, wherein the bore's cross-sectional area is circular.
Type: Application
Filed: Feb 13, 2012
Publication Date: Aug 15, 2013
Applicant: FORD GLOBAL TECHNOLOGIES, LLC (DEARBORN, MI)
Inventor: Darryl Leigh Young (Canton, MI)
Application Number: 13/371,488
International Classification: B21D 37/00 (20060101); B21D 22/00 (20060101);