EDM apparatus and method incorporating combined electro-erosion and mechanical sawing features

• US 6,737,602 B2
• Filed: 09/24/2002
• Issued: 05/18/2004
• Est. Priority Date: 09/24/2002
• Status: Expired due to Fees

• Current Assignee: Brian Stelter
• Original Assignee: Brian Stelter
• Inventors: Stelter, Brian
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US10/253,463
• Publication Number:
  US 20040056003A1
• Time in Patent Office: 602 Days
• Field of Search: 219/69.12
• US Class Current: 219/69.12
• CPC Class Codes: B23H 5/04 Electrical discharge machining combined with mechanical working
• CPC Class Codes: B23H 7/02 Wire-cutting
• CPC Class Codes: B23H 7/08 Wire electrodes

Abstract

A system and method for accomplishing combined electro-erosion and mechanical cutting of a workpiece which includes an outer metallic jacket and a non-metallic inner core. An elongated wire electrode is provided and is unwound from a supply spool through a pair of forming rollers, during which a specified polygonal and cross sectional shape with a textured outer surface is imparted upon the electrode. Pairs of feed rollers are located to each of supply and take-up sides relative the workpiece, and with the electrode being guidably extended between each of the pairs of rollers. Tensioning rollers are also located on each of the feed and take-up sides of the electrode. An electrical current generating and delivery component is provided in communication with the electrode which electro-erodes the outer metallic jacket of the workpiece. The textured surface of the electrode preferably exhibits teeth which mechanically abrade, when advanced longitudinally in relation to the workpiece, its inner core and in order to cut through and section the inner core.

Claims

1. A system for accomplishing combined electro-erosion and mechanical cutting of a workpiece having an outer metallic jacket and a non-metallic inner core, said system comprising:

an elongated wire electrode having a specified polygonal and cross sectional shape with a textured outer surface;

at least a first pair of feed rollers located to one side of the workpiece and a second pair rollers located to the other side, said electrode being guidably extended between each of said pairs of rollers;

an electrical current generating and delivery component in communication with said wire electrode, through at least one of said rollers, and such that said electrode exhibits current carrying and electro-erosive capability when arranged in proximity to the outer metallic jacket of the workpiece; and

said textured surface of said electrode further exhibiting mechanically abrasive properties when advanced longitudinally in relation to the inner core of the workpiece and in order to cut through and section the inner core.

2. The system as described in claim 1, further comprising a reel spool containing a wound quantity of said elongated wire electrode.

3. The system as described in claim 2, further comprising a pair of forming rollers such that, upon said wire electrode unreeling from said reel spool and passing through said forming rollers, said forming rollers imparting said specified polygonal cross sectional shape and said textured outer surface.

4. The system as described in claim 3, said specified cross sectional shape of said wire further comprising a triangular shape, said textured outer surface further comprising teeth imparted by said forming rollers upon said outer surface of said electrode.

5. The system as described in claim 3, said first pair of rollers further comprising feed rollers and said second pair of rollers further comprising take-up rollers.

6. The system as described in claim 5, further comprising a take-up spool for rewinding a used quantity of said wire electrode.

7. The system as described in claim 6, a pair of pulling pinch rollers being arranged between said take-up rollers and said take-up spool and through which wire electrode is guidably received.

8. The system as described in claim 7, further comprising tensioning members located on both feed and take-up sides of said wire electrode.

9. The system as described in claim 8, said tensioning members further comprising a first potentiometer roller arranged between said reel spool and said forming rollers, a second potentiometer roller being arranged between said take-up rollers and said pulling pinch rollers.

10. The system as described in claim 1, further comprising a fluidic and die-electric located between said wire electrode and the workpiece.

11. The system as described in claim 1, said system further comprising an advancing head mechanism for actuating said wire electrode in a direction substantially perpendicular to an extending length across a machining zone defined in relation to the workpiece.

12. The system as described in claim 11, said wire electrode further comprising an outer layer constructed of a first and softer metallic material and an inner layer constructed of a second and harder metallic material in relation to said outer layer.

13. The system as described in claim 12, said outer layer further comprising brass and said inner layer further comprising steel.

14. The system as described in claim 11, said advancing head mechanism having a specified shape and size, the workpiece further being an explosive shell filled with an RDX explosive aggregate, a detonator being located at an extending end of the shell.

15. A method for accomplishing combined electro-erosion and mechanical cutting of a workpiece having an outer metallic jacket and a non-metallic inner core, said method comprising the steps of:

unreeling a supply of an elongated wire electrode;

forming a specified polygonal and cross sectional shape of said electrode, said step of forming further comprising the step of texturing an outer surface of said electrode;

guidably advancing, in longitudinal fashion, said wire electrode across a machining zone defined between said wire electrode and the workpiece;

supplying an electrical current to said wire electrode to create an electrical arc within said machining zone, between said electrode and the workpiece, and in order to electro-erode the outer metallic jacket; and

sectioning the non-metallic inner core of the workpiece upon the advancement and abrading of said textured outer surface of said wire electrode against the inner core.

16. The method as described in claim 15, further comprising the step of tensioning said wire electrode on both of feed and take-up sides relative to said machining zone.

17. The method as described in claim 15, the step of forming a polygonal and cross sectional shape of said electrode further comprising a triangular shape.

18. The method as described in claim 17, said step of texturing said outer surface of said electrode further comprising forming a plurality of teeth thereupon.

19. The method as described in claim 15, further comprising the step of immersing said machining zone with a dielectric fluidic bath.

20. The method as described in claim 15, further comprising the step of advancing said wire electrode in a direction substantially perpendicular to an extending length across said machining zone and in relation to the workpiece.

21. A system for providing combined electroerosion and mechanical cutting of a workpiece having a first conductive layer and a second sandwiching and nonconductive layer, said system comprising:

an elongated wire electrode having a specified polygonal and cross sectional shape with a textured outer surface;

at least a first pair of feed rollers located to one side of the workpiece and a second pair rollers located to the other side, said electrode being guidably extended between each of said pairs of rollers;

an electrical current generating and delivery component in communication with said wire electrode, through at least one of said rollers, and such that said electrode exhibits current carrying and electro-erosive capability when arranged in proximity to the first conductive layer of the workpiece; and

said textured surface of said electrode further exhibiting mechanically abrasive properties when advanced longitudinally in relation to the second nonconductive layer of the workpiece and in order to cut through and section the second layer.