Electrochemical grinding with a conductivity-controlled wheel electrode

• US 4,013,526 A
• Filed: 04/14/1975
• Issued: 03/22/1977
• Est. Priority Date: 04/12/1974
• Status: Expired due to Term

• Current Assignee: Inoue-Japax Research Incorporated
• Original Assignee: Inoue-Japax Research Incorporated
• Inventors: Inoue, Kiyoshi
• Primary Examiner(s): Tung, T.
• Application Number:
  US05/567,527
• Time in Patent Office: 708 Days
• Field of Search: 204/129.2, 204/129.25, 204/129.43, 204/129.46, 204/129.5
• US Class Current: 205/663
• CPC Class Codes: B23H 5/08 Electrolytic grinding

Abstract

An electrochemical grinding wheel of substantially uniform conductivity along its contoured grinding surfaces is modified to reduce the conductivity at locations generally parallel to the tool-feed direction (perpendicular to the machine surface) so that electrochemical removal of material from the workpiece occurs substantially only at those surfaces which are transverse to the tool-feed direction. This prevents overcutting of the workpiece.

Claims

1. A method of electrochemically grinding a workpiece by a rotating electrically conductive, abrasive wheel electrode with a machining surface constituted by an electrically conductive matrix and a layer of electrically nonconductive abrasive protrusions projecting therefrom, said method comprising the steps of:

a. preparing said wheel electrode with the machining surface of a contour corresponding to a shape to be imparted to said workpiece,

b. treating said machining surface by electrochemically solubilizing said conductive matrix at said machining surface so as to impart thereto a conductivity which locally varies as a function of the shape of said machining surface, and

c. electrochemically grinding said workpiece with said treated machining surface.

2. The method defined in claim 1 wherein in step (b) electrically conductive material is removed from the surface region of said electrode and the thickness of said layer is thereby controlled so as to obtain the desired conductivity distribution in said machining surface.

3. The method defined in claim 1 wherein in step (a) said contour is formed on said wheel electrode by mechanically dressing the same.

4. The method defined in claim 3 wherein said steps (a) and (b) are carried out concurrently.

5. A method of electrochemical grinding which comprises the steps of:

a. forming an electrochemical grinding wheel with a contoured machining surface and a substantially uniform electrical conductivity along said surface;

b. selectively decreasing the electrical conductivity of portions of said surface extending generally parallel to a tool-feed direction by electrochemical solubilization of conductive material from said wheel;

c. rotating said wheel in contact with a workpiece while supplying an electrolyte to the region of contact of said wheel with said workpiece and passing an electric current through said wheel and said workpiece to anodically solubilize portions of said workpiece juxtaposed with relatively more conductive portions of said surface; and

d. feeding said wheel into said workpiece parallel to said direction by relatively displacing said wheel and said workpiece.

6. The method defined in claim 5 wherein said wheel is formed with said surface of substantially uniform conductivity in step (a) by chemically plating the wheel with metal.

7. A method of electrochemical grinding which comprises the steps of:

a. forming an electrochemical grinding wheel with a contoured machining surface and a substantially uniform electrical conductivity along said surface;

b. selectively decreasing the electrical conductivity of portions of said surface extending generally parallel to a tool-feed direction;

c. rotating said wheel in contact with a workpiece while supplying an electrolyte to the region of contact of said wheel with said workpiece and passing an electric current through said wheel and said workpiece to anodically solubilize portions of said workpiece juxtaposed with relatively more conductive portions of said surface; and

d. feeding said wheel into said workpiece parallel to said direction by relatively displacing said wheel and said workpiece, the conductivity of portions of said surface being reduced in step (b) by electrochemically solubilizing material from said surface.

8. The method defined in claim 7 wherein material is electrochemically solubilized from said surface by the steps of:

b₁. mechanically grinding a conductive body with said wheel to impart to said body a contour complementary to that of said wheel;

b₂. withdrawing said body as shaped in step (b₁) from said surface to form a gap therewith;

b₃. supplying an electrolyte to said gap; and

b₄. connecting said body and said wheel to an electrical source to anodically solubilize said material from said wheel with electrolyte supplied to said gap.

9. The method defined in claim 7 wherein material is electrochemically removed from said wheel by:

b₁. juxtaposing the surface of said wheel parallel to said direction with a stylus;

b₂. supplying an electrolyte to the stylus and the wheel in the region of juxtapose position thereof, and

b₃. electrically connecting said stylus and said wheel to anodically solubilize said material from said wheel.

10. The method defined in claim 9, further comprising the step of dressing said wheel with said stylus.

11. The method defined in claim 9 further comprising the step of displacing said stylus generally parallel to said direction and controlling the degree of anodic solubilization of said material in accordance with the particular position of said stylus in the displacement thereof.

12. The method defined in claim 7, further comprising the steps of measuring the electrical conductivity of portions of said surface and terminating the removal of material therefrom upon the measured conductivity attaining a predetermined value.