Explosion forming system

• US 9,737,922 B2
• Filed: 04/03/2013
• Issued: 08/22/2017
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: Magna International Incorporated
• Original Assignee: Magna International Incorporated
• Inventors: Zak, Alexander, Kotagiri, Seetarama S., Horton, Frank A.
• Primary Examiner(s): KATCOFF, MATTHEW GORDON
• Application Number:
  US13/855,896
• Publication Number:
  US 20130219980A1
• Time in Patent Office: 1,602 Days
• CPC Class Codes: B21D 26/08 generated by explosives, e.g. chemical explosives

Abstract

An explosion forming apparatus (10) that preferably utilizes a shock wave (42) directed along a work piece (12) to progressively conform the work piece to a contour die cavity (44).

Claims

1. An apparatus for modifying a work piece, comprising:

an ignition chamber for the generation of an explosion;

a die having at least one wall defining a die cavity for receiving the work piece, the die cavity having a pressure inlet at one end of the die cavity and a pressure outlet at another end of the die cavity and wherein, the ignition chamber is fluidly connectable to the die cavity for the transmission of a pressure wave resulting from the explosion through the die cavity from the pressure inlet to the pressure outlet such that, in operation, the pressure wave modifies the work piece to at least partially conform to the at least one die cavity wall; and

a pressure reducer disposed downstream of the die cavity pressure outlet that is configured to at least partially destroy the pressure wave.

2. An apparatus as claimed in claim 1, wherein the pressure reducer includes a plurality of reflective elements positioned to disrupt the shockwave.

3. An apparatus as claimed in claim 1, further comprising an incompressible fluid inlet valve positioned to transfer incompressible fluid into the die cavity pressure outlet, wherein the pressure reducer is positioned fluidly between the die cavity pressure outlet and the incompressible fluid inlet valve.

4. An apparatus for modifying a work piece having a longitudinal length, the apparatus comprising:

an ignition chamber configured for generating a shock wave that has a shock wave length that is less than the longitudinal length of the work piece;

a die having a die cavity for receiving the work piece, the die cavity having a pressure inlet at one end of the die cavity and a pressure outlet at another end of the die cavity;

a transfer structure configured to convey the shock wave from the ignition chamber into the die cavity;

wherein, in operation, the shock wave applies a localized pressure to the work piece in a direction that is transverse to the direction of travel of the shock wave, and wherein the die is holdable in the closed position by a selected die holding force; and

a pressure reducer disposed downstream of the work piece configured to at least partially destroy the shock wave.

5. An apparatus as claimed in claim 4, wherein the pressure reducer includes a plurality of reflective elements positioned to disrupt the shock wave.

6. An apparatus as claimed in claim 4, further comprising an incompressible fluid inlet valve positioned to transfer incompressible fluid into the die cavity pressure outlet, wherein the pressure reducer is positioned fluidly between the die cavity pressure outlet and the incompressible fluid inlet valve.

7. An apparatus for modifying a tubular work piece having a tubular wall and a tubular length, the apparatus comprising:

an ignition chamber configured for generating a shock wave that has a shock wave length that is less than the tubular length of the work piece;

a die having at least one wall defining a die cavity for receiving the work piece, the die cavity having a pressure inlet at one end of the die cavity and a pressure outlet at another end of the die cavity;

a transfer structure configured to convey the shock wave from the ignition chamber into the die cavity;

wherein, in operation, the shock wave applies a localized pressure to the tubular wall of the work piece in a direction that is transverse to the direction of travel of the shock wave so as to at least partially conform the tubular wall of the work piece against the at least one die wall; and

a pressure reducer disposed downstream of the work piece configured to at least partially destroy the pressure wave, the pressure reducer being disposed upstream of one or more valves fluidly connectable to the die cavity.

8. An apparatus as claimed in claim 7, wherein the pressure reducer includes a plurality of reflective elements positioned to disrupt the shock wave.

9. An apparatus as claimed in claim 7, further comprising an incompressible fluid inlet valve positioned to transfer incompressible fluid into the die cavity pressure outlet, wherein the pressure reducer is positioned fluidly between the die cavity pressure outlet and the incompressible fluid inlet valve.

10. A method for modifying a tubular work piece, comprising:

a) providing an ignition chamber;

b) providing a die having a die cavity for receiving the work piece;

c) transferring the work piece into the die cavity, the die cavity having a pressure inlet at one end of the die cavity and a pressure outlet at another end of the die cavity;

d) generating an explosion in the ignition chamber to generate a pressure wave in the ignition chamber;

e) transmitting the pressure wave from the ignition chamber to the work piece to modify the work piece;

f) transmitting the pressure wave out of the die cavity after step e);

g) at least partially destroying the pressure wave after step f); and

h) ejecting the work piece from the die cavity after step f).

11. A method as claimed in claim 10, wherein the pressure wave is a shock wave.