Process for applying control variables having fractal structures

• US 5,486,280 A
• Filed: 10/20/1994
• Issued: 01/23/1996
• Est. Priority Date: 10/20/1994
• Status: Expired due to Fees

• Current Assignee: Martin Marietta Energy Systems, Inc.
• Original Assignee: Martin Marietta Energy Systems, Inc.
• Inventors: Lawson, Roger L., Bullock, Jonathan S. IV
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Mee, Brendan
• Application Number:
  US08/326,425
• Time in Patent Office: 460 Days
• Field of Search: 205/87, 205/102, 205/103, 205/104, 204/DIG. 9, 204/228
• US Class Current: 205/67
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C25D 1/00 Electroforming
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 5/605 Surface topography of the layers, e.g. rough, dendritic or nodular layers
• CPC Class Codes: Y10S 204/09 Wave forms

Abstract

A process and apparatus for the application of a control variable having a fractal structure to a body or process. The process of the present invention comprises the steps of generating a control variable having a fractal structure and applying the control variable to a body or process reacting in accordance with the control variable. The process is applicable to electroforming where first, second and successive pulsed-currents are applied to cause the deposition of material onto a substrate, such that the first pulsed-current, the second pulsed-current, and successive pulsed currents form a fractal pulsed-current waveform.

Claims

1. A process for applying a fractal pulsed-current waveform across a substrate and an electrode located in an electrolyte to cause the deposition of a material on the substrate, comprising the steps of:

applying a first pulsed-current waveform to cause the deposition of the material onto the substrate;

applying a second pulsed-current waveform to cause the deposition of the material onto the substrate;

the first pulsed-current waveform and the second pulsed-current waveform forming a fractal pulsed-current waveform.

2. The process according to claim 1, wherein the first pulsed-current waveform comprises a series of cathodic pulses followed by a first anodic pulsed-current.

3. The process according to claim 2, wherein the second pulsed-current waveform comprises the first pulsed-current waveform repeated a predetermined number of times followed by a second anodic pulsed-current distinct from the first anodic pulsed-current.

4. The process according to claim 3, wherein the second anodic pulsed-current has a longer duration than the first anodic pulsed-current.

5. The process according to claim 2, wherein the first pulsed-current waveform is repeated a predetermined number of times.

6. The process according to claim 5, wherein the second pulsed-current waveform comprises the first pulsed-current waveform repeated a predetermined number of times followed by a second anodic pulsed-current.

7. The process according to claim 6, wherein the second anodic pulsed-current has a longer duration than the first anodic pulsed-current.

8. The process according to claim 1, wherein the second pulsed-current waveform comprises the first pulsed-current waveform repeated a predetermined number of times followed by a secondary pulsed-current waveform distinct from the first pulsed-current waveform.

9. The process according to claim 1, further comprising the step of applying successive pulsed-current waveforms to cause the deposition of the material onto the substrate.

11. The process according to claim 5, wherein the first pulsed-current waveform comprises a series of cathodic pulses followed by a first anodic pulsed-current.

12. The process according to claim 11, wherein the second pulsed-current waveform comprises the first pulsed-current waveform repeated a predetermined number of times followed by a second anodic pulsed-current distinct from the first anodic pulsed current.

13. The process according to claim 12, wherein the second anodic pulsed-current has a longer duration than the first anodic pulsed-current.

14. The process according to claim 11, wherein the first pulsed-current waveform is repeated a predetermined number of times.

15. The process according to claim 14, wherein the second pulsed-current waveform comprises the first pulsed-current waveform repeated a predetermined number of times followed by a second anodic pulsed-current.

16. The process according to claim 15, wherein the second anodic pulsed-current has a longer duration than the first anodic pulsed-current.

10. A process for electroforming, comprising the steps of:

applying a pulsed-current waveform across a substrate and an electrode located in an electrolyte to cause the deposition of a material on a surface of the substrate;

the pulsed-current waveform having a fractal waveform selected to achieve a desired characteristic of the material deposited on the surface of the substrate,

wherein the fractal waveform comprises a first pulsed-current waveform and a second pulsed-current waveform.

17. The process according to claim 10, wherein the second pulsed-current waveform comprises the first pulsed-current waveform repeated a predetermined number of times followed by a secondary pulsed-current waveform distinct from the first pulsed-current waveform.