Method for the production of drill holes in difficult to machine materials

Patent metadata

Field	Value
Publication number	US-11471964-B2
Application number	US-201916534790-A
Country	US
Kind code	B2
Filing date	Aug 7, 2019
Priority date	Aug 9, 2018
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

The present invention relates to a method for the production of drill holes in difficult to machine materials, in which a removal of material takes place in order to produce a drill hole by electrochemical erosion of material by an electrode that is moved in the longitudinal direction of the drill hole being produced in the direction onto the material to be processed at a feed rate, wherein the drilling has at least two steps, wherein, in the first step, the electrochemical processing takes place, and wherein, in a second step, the further processing of the drill hole to the final diameter takes place by machining processing or by erosion or by an electrochemical processing.

First claim

What is claimed is:

1. A method for the production of drill holes having improved surface quality and dimensional accuracy in difficult to machine materials, in which a removal of material takes place in order to produce a drill hole by electrochemical erosion of material by first and second electrodes that are moved in the longitudinal direction of the drill hole being produced in the direction onto the material to be processed at a feed rate, wherein the drilling proceeds in at least two steps,
wherein, in the first step, the electrochemical processing takes place using the first electrode having an electrode tip on which at least one electrochemically active side wall is formed that runs obliquely to the longitudinal axis of the first electrode, in which the feed rate of the first electrode is less than or equal to 5 mm/min during the electrochemical material erosion and the drill hole is fabricated with a drill hole diameter that is 0.05 to 2 mm smaller than a final diameter of the drill hole,
wherein, in a second step, the further processing of the drill hole to the final diameter takes place by an electrochemical processing using the second electrode having at least one side wall that encloses an angle between 1 and 60° with the longitudinal axis of the electrode that runs along the direction of the electrode advance in which the feed rate of the second electrode is greater than 50 mm/min and less than or equal to 60 mm/min, and
wherein the difficult to machine materials are alloys based on Ti, Fe, Ni, or Mo, and the difficult to machine materials are alloys produced by powder metallurgy.

2. The method according to claim 1 , wherein, during the electrochemical processing in the second step, a gap is established between the second electrode and the material being processed, the gap being less than or equal to 75 μm.

3. The method according to claim 1 , wherein the first and/or second electrodes are rotated around the electrode longitudinal axis during the electrochemical processing in the first and/or second step.

4. The method according to claim 1 , wherein, after the second step of the processing, a third processing step takes place, wherein, in the third step, the further processing of the drill hole to the final diameter takes place by machining processing or by erosion.

5. The method according to claim 1 , wherein, during the electrochemical processing, the edge of the drill hole at an inlet and/or outlet side of the drill hole for the electrode is covered by a seal having an opening corresponding to the size of the drill hole, or a metal sealing element that is likewise to be drilled through.

6. The method according to claim 1 , wherein, during the electrochemical processing, an electrolyte necessary for processing is introduced in the direction of advance of the second electrode, during the electrochemical processing in the first step of the drilling, and/or is introduced counter to the direction of advance of the second electrode, during the electrochemical processing in the second step of the drilling.

7. The method according to claim 1 , wherein, during the electrochemical processing, an electrolyte is provided on the side of the material being processed, which is the outlet side of the drill hole for the first and second electrodes, prior to the withdrawal of the first and second electrodes.

8. The method according to claim 1 , wherein a plurality of drill holes is produced in parallel with a plurality of first and second electrodes running in parallel.

9. The method according to claim 1 , wherein the method is used for components of turbomachines or aircraft engines.

10. The method according to claim 1 , wherein the obliquely running side wall is the side wall of a cone or truncated cone.

Assignees

• MTU Aero Engines AG

Inventors

• Platz Albin
• Feiling Nicole
• Kuepper Anna Carina
• Huber Norbert

Classifications

• B23H2600/10

  Switching of machining conditions during machining · CPC title

• B23H3/00 Primary

  Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte · CPC title

• B23H7/26

  Apparatus for moving or positioning electrode relatively to workpiece; Mounting of electrode · CPC title

• B23H9/14

  Making holes · CPC title

• B23H3/04 Primary

  Electrodes specially adapted therefor or their manufacture (B23H9/00 takes precedence) · CPC title