Method of and apparatus for machining ceramic materials

• US 4,559,115 A
• Filed: 05/30/1984
• Issued: 12/17/1985
• Est. Priority Date: 05/30/1983
• Status: Expired due to Term

• Current Assignee: Inoue-Japax Research Incorporated
• Original Assignee: Inoue-Japax Research Incorporated
• Inventors: Inoue, Kiyoshi
• Primary Examiner(s): Valentine, Donald R.
• Application Number:
  US06/615,416
• Time in Patent Office: 566 Days
• Field of Search: 204/129.1, 204/129.3, 204/129.5, 204/129.6, 204/129.46, 204/217, 204/224 M, 219/69 M, 219/69 R, 219/68
• US Class Current: 205/651
• CPC Class Codes: B23K 2103/52 Ceramics
• CPC Class Codes: B23K 26/12 in a special atmosphere, e.g. in an enclosure
• CPC Class Codes: B23K 26/127 in an enclosure
• CPC Class Codes: B23K 26/16 Removal of by-products, e.g. particles or vapours produced during treatment of a workpiece by a fluid stream B23K26/142
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23P 25/006 Heating the workpiece by laser during machining
• CPC Class Codes: B24B 1/00 Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
• CPC Class Codes: C25F 3/14 locally
• CPC Class Codes: C25F 7/00 Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects for both electrolytic coating and removal C25D; Servicing or operating

Abstract

Efficient, high-precision machining of ceramic materials is achieved by supplying onto a workpiece of a ceramic material a liquid electrolyte having components at least one of which is normally inert to but becomes chemically reactive with the ceramic material at an elevated temperature, and applying to a limited zone of interface between the liquid electrolyte and the workpiece, localized energy of a magnitude sufficient to heat the liquid electrolyte and the ceramic material there to the elevated temperature and to remove from the workpiece the locally heated ceramic material in a form at least partially chemically degenerated with that electrolytic component. The limited zone acquiring the localized energy is displaced in a scanning manner from one region to another on the workpiece along numerically programmed path to consecutively remove the ceramic material along the path from the workpiece.

Claims

1. A method of machining a workpiece of a ceramic material, comprising the steps of:

bringing into contact with the workpiece a liquid electrolyte having at least one component which is chemically reactive with the ceramic material at an elevated temperature;

applying to a limited zone of interface between said liquid electrolyte and said workpiece, localized energy of a magnitude sufficient to heat said liquid electrolyte and said material at said limited zone to said elevated temperature and to remove from the workpiece the locally heated material at said limited zone in a form at least partially chemically degenerated with said at least one component; and

displacing, in a scanning manner, said limited zone acquiring said localized energy from one region to another on said workpiece along a programmed continuous path to continuously remove said material along said path from the workpiece,

said localized energy being applied by irradiating said limited zone with an energy beam, said zone being displaced along said path by relatively displacing said energy beam and said workpiece along said programmed path, a portion of said localized energy being applied to said limited zone by disposing a pair of electrodes closely spaced apart from each other adjacent to said limited zone and effecting a succession of electrical discharges through said liquid electrolyte across said electrodes, said electrodes and said workpiece being also relatively displaced in a said scanning manner to displace said limited zone from one region to another on the workpiece along said programmed path.

2. The method defined in claim 1 wherein said energy beam is a laser beam.

3. The method defined in claim 1 wherein said energy beam is a microwave beam.

4. A method of machining of a ceramic material, comprising the steps of:

bringing into contact with the workpiece a liquid electrolyte having at least one component which is chemically reactive with the ceramic material at an elevated temperature;

applying to a limited zone of interface between said liquid electrolyte and said workpiece, localized energy of a magnitude sufficient to heat said liquid electrolyte and said material at said limited zone to said elevated temperature and to remove from the workpiece the locally heated material at said limited zone in a form at least partially chemically degenerated with said at least one component; and

displacing, in a scanning manner, said limited zone acquiring said localized energy from one region to another on said workpiece along a programmed continuous path to continuously remove said material along said path from the workpiece, said localized energy comprising at least two different forms of energy, a first of which is applied to said limited zone to heat it to said elevated temperature and a second of which is applied to said zone so heated by said first form of energy to mechanically facilitate removal of said locally degenerated ceramic material from the workpiece.

5. A method of machining a workpiece of a ceramic material, comprising the steps of:

bringing into contact with the workpiece a liquid electrolyte having at least one component which is chemically reactive with the ceramic material at an elevated temperature;

applying to a limited zone of interface between said liquid electrolyte and workpiece, localized energy of a magnitude sufficient to heat said liquid electrolyte and said material at said limited zone to said elevated temperature and to remove from the workpiece the locally heated material at said limited zone in a form at least partially chemically degenerated with said at least one component; and

displacing, in a scanning manner, said limited zone acquiring said localized energy from one region to another on said workpiece along a programmed continuous path to continuously remove said ceramic material along said path from the workpiece,

said localized energy being applied to said limited zone by disposing a pair of electrodes so that they are spaced apart across a small gap adjacent to said zone and effecting a succession of electrical discharges through said liquid electrolyte across said electrodes, said electrodes and said workpiece being relatively displaced along said programmed path to displace said limited zone from one region to another on the workpiece.

6. The method defined in claim 5 wherein said electrodes are forwardly inclined to approach each other toward said workpiece so as to form said small spacing adjacent to said workpiece.

7. The method defined in claim 5 or claim 6 wherein at least one of said electrodes is disk-shaped.

8. The method defined in claim 5 or claim 6, further comprising disposing a partition substantially composed of an insulating material between said electrodes so as to confine development of said electrical discharges through said liquid electrolyte adjacent to said limited zone.

9. An apparatus for machining a workpiece of a ceramic material, comprising:

means for supplying onto the workpiece a liquid electrolyte having at least one component which is chemically reactive with the ceramic material at an elevated temperature;

means for applying to a limited zone of interface between said liquid electrolyte and said workpiece, localized energy of a magnitude sufficient to heat said liquid electrolyte and said material at said limited zone to said elevated temperature and to remove from the workpiece the locally heated material at said limited zone in a form at least partially chemically degenerated with said at least one component; and

means for displacing, in a scanning manner, said limited zone acquiring said localized energy from one region to another on said workpiece along a programmed continuous path to continuously remove said material along said path from the workpiece,

said means for applying comprising a pair of electrodes juxtaposed with each other across a small gap spacing adjacent to said zone, and a power supply for energizing said electrodes to produce thereacross a succession of electrical discharges through said liquid electrolyte.

10. The apparatus defined in claim 9 wherein said means for applying further includes a beam gun for irradiating said limited zone of interface with an energy beam.

11. The apparatus defined in claim 10 wherein said electrodes are forwardly inclined to approach each other towards said workpiece so as to form said small spacing adjacent to said workpiece.

12. The apparatus defined in claim 11 wherein said electrodes are axially elongated to form said small gap spacing at their forward end portions.

13. The apparatus defined in claim 10, claim 11, claim 12, further comprising a partition member substantially composed of an insulating material between said electrodes so as to confine development of said electrical discharges through said liquid electrolyte adjacent to said successive limited zones.

14. The apparatus defined in claim 10, or claim 9, further comprising means for abrading said at least partially chemically degenerated zone to mechanically facilitate dislodgement thereof from said workpiece.

15. A method of machining a workpiece of a dielectric material, comprising the steps of:

flushing onto the workpiece a fluid having at least one component to which said dielectric material is normally inert but with which it becomes chemically reactive at an elevated temperature;

irradiating a limited zone on said workpiece traversed by said flushing fluid, with an energy beam with localized energy of a magnitude sufficient to locally heat said dielectric material at said limited zone to said elevated temperature;

applying to said limited zone further localized energy of a magnitude sufficient to mechanically dislodge from the workpiece the locally heated dielectric material at said zone in a form at least partially chemically degenerated with said at least one component and to permit the dislodged material to be carried away with said flushing fluid; and

relatively displacing said energy beam and said workpiece automatically in a predetermined scanning manner to shift said limited zone of irradiation of said energy beam progressively over a programmed region of the workpiece so that the workpiece is selectively machined in said region.

16. The method defined in claim 15 wherein said fluid is flushed in contact with said workpiece at a velocity ranging between 10 and 100 meters/second.

17. The method defined in claim 15 wherein said component includes a strong acid.

18. The method defined in claim 15 wherein said component includes a strong base.

19. A method of machining a workpiece of a dielectric material which becomes electrically conductive at an elevated temperature, comprising the steps of:

flushing a conductive fluid in contact with the workpiece;

irradiating a limited zone on said workpiece traversed by said flushing fluid, with an energy beam with localized energy of a magnitude sufficient to locally heat said dielectric material at said zone to said elevated temperature, thereby rendering said material at said limited zone selectively electrically conductive;

disposing a pair of electrodes so that they are spaced apart from each other across a small gap adjacent said zone and effecting a succession of electrical discharges through said conductive fluid and said dielectric material rendered conductive at said zone adjacent said gap to erosively dislodge said material at said zone from the workpiece; and

relatively displacing said energy beam and said electrodes on the one hand and said workpiece on the other hand in a predetermined scanning manner to shift said zone of localized heating and material dislodgment progressively over a programmed region of the workpiece so that the workpiece is selectively machined in said region.

20. An apparatus for machining a workpiece of a dielectric material, comprising:

means for flushing onto the workpiece a solution having at least one component to which said dielectric material is normally inert but with which it at an elevated temperature becomes chemically reactive;

means for irradiating a limited zone on said workpiece through said flushing solution with an energy beam with localized energy of a magnitude sufficient to locally heat said dielectric material flushed with said solution at said limited zone to said elevated temperature;

means for applying to said limited zone further localized energy of a magnitude sufficient to mechanically dislodge from the workpiece the locally heated dielectric material at said zone in a form at least partly chemically degenerated with said at least one component and to permit the dislodged material to be carried away with said flushing solution; and

numerically controlled drive means for relatively displacing said energy beam and said workpiece automatically in a predetermined scanning manner to shift said limited zone of irradiation of said energy beam progressively over a programmed region of the workpiece so that the workpiece is selectively machined in said region.

21. An apparatus for machining a workpiece of dielectric material which becomes electrically conductive at an elevated temperature, comprising:

means for flushing a liquid electrolyte in contact with the workpiece;

means for irradiating a limited zone on said workpiece through said flushing liquid electrolyte and said workpiece with an energy beam with localized energy of a magnitude sufficient to locally heat said dielectric material at said limited zone to said elevated temperature, thereby rendering said material at said zone selectively electrically conductive;

means including a pair of electrodes disposed spaced apart across a small gap adjacent said zone and a power supply for effecting a succession of electrical discharges through said liquid electrolyte and said material rendered conductive at said limited zone to remove said material at said zone from the workpiece; and

numerically controlled drive means for relatively displacing said beam and said electrode on one part and said workpiece on the other part in a predetermined scanning manner to shift said zone of localized heating and material removal progressively over a programmed region of the workpiece so that the workpiece is selectively machined in said region.