Use of a diamond layer doped with foreign atoms to detect the degree of wear of an undoped diamond function layer of a tool

Patent metadata

Field	Value
Publication number	US-10974360-B2
Application number	US-201916568883-A
Country	US
Kind code	B2
Filing date	Sep 12, 2019
Priority date	Mar 13, 2017
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A first diamond layer made of polycrystalline diamonds and doped with foreign atoms, is arranged on a metal surface of a machining tool, and is used to detect the degree of wear of an undoped polycrystalline second diamond layer, which is arranged on the doped diamond layer and forms a functional region of the machining tool, wherein at least one physical parameter is detected continuously or periodically during operation of the tool, and wherein a change in the parameter indicates the degree of wear of the undoped second diamond layer. The doped diamond layer forms an “intelligent stop layer” for the tool because as a result of change in the transition from the undoped to the doped layer, the conductivity of the system changes, for example, and this change can be used to form a stop signal for the machine drive before the tool and the machined workpiece are damaged.

First claim

The invention claimed is:

1. A machining tool comprising:
a metallic substrate layer having a cobalt-containing hard metal surface;
a first diamond layer, which is doped with foreign atoms and which is made of polycrystalline diamonds and which is arranged on the metallic substrate layer; and
an undoped polycrystalline second diamond layer, which is arranged on the first diamond layer and which forms a functional region of the machining tool, whereby detecting change in at least one physical parameter during operation of the tool indicates wear of the undoped second diamond layer.

2. The machining tool according to claim 1 , wherein the first diamond layer is an n-type doped or a p-type doped diamond layer.

3. The machining tool according to claim 1 , wherein the foreign atoms are selected from the group consisting of: aluminum, boron, silicon, tungsten, iron, molybdenum, cobalt, niobium, tantalum, rhenium, nitrogen, and phosphor, as well as mixtures thereof.

4. The machining tool according to claim 1 , wherein at least some of the foreign atoms are boron atoms.

5. The machining tool according to claim 1 , wherein at least some of the foreign atoms are nitrogen atoms or phosphor atoms.

6. The machining tool according to claim 1 , wherein the at least one physical parameter is/are selected from the group consisting of the electrical resistance, the electrical conductivity, the capacitive resistance, the Hall voltage and the Hall current of a Hall sensor.

7. The machining tool according to claim 1 , wherein the physical parameter is detected between the tool and a machined workpiece.

8. The machining tool according to claim 7 , wherein the at least one physical parameter is/are selected from the electrical conductivity, the electrical resistance, and the capacitance between machined workpiece and the tool.

9. The machining tool according to claim 1 , wherein the doped and the undoped diamond layer are applied to the metal surface by chemical vapor deposition (CVD) from a methane/hydrogen atmosphere.

10. The machining tool according to claim 1 , wherein the doping of the first diamond layer is created by supply of a doping gas, during a CVD method in a CVD chamber.

11. The machining tool according to claim 1 , wherein the undoped second diamond layer is created by interruption of the supply of the doping gas into the CVD chamber.

12. The machining tool according to claim 1 , wherein the first polycrystalline diamond layer is produced by CVD, and the obtained layer is irradiated with an ion beam of the desired foreign atom for doping the first diamond layer; and then a tempering step is carried out; and the undoped second diamond layer is then deposited on the doped first diamond layer.

13. A machining tool as recited in claim 1 , wherein the cobalt-containing hard metal surface has been subjected to at least one of an ion beam treatment and a chemical treatment to improve adhesion of the first diamond layer to the metallic substrate layer.

14. A machining tool as recited in claim 1 , wherein the cobalt-containing hard metal surface has been subjected to acidic etching to remove some cobalt from the cobalt-containing hard metal surface.

15. A machining tool as recited in claim 1 , wherein the machining tool further comprises at least one Hall effect probe.

16. A method for detecting wear of an undoped diamond layer, which is arranged on a first doped diamond layer which is arranged on a metallic substrate layer, in which the undoped diamond layer forms a functional region of a machining tool, and is arranged on a diamond layer doped with foreign atoms, during operation of the tool, the method comprising:
a) detecting at least one measurement parameter, which results from the undoped and doped diamond layers, the tool, and a workpiece machined with the tool, continuously or periodically during operation of the tool; and
b) determining whether the measurement parameter passes a predefined threshold value that indicates a degree of wear of the undoped diamond layer.

17. The method according to claim 16 , wherein the measurement parameter is the Hall effect.

18. The method according to claim 16 , wherein the foreign atoms are selected from the group consisting of: aluminum, boron, silicon, tungsten, iron, molybdenum, cobalt, niobium, tantalum, rhenium, nitrogen, and phosphor, as well as mixtures thereof.

19. The method according to claim 16 , wherein the foreign atoms comprise at least one of boron, nitrogen and phosphorus.

20. The method according to claim 16 , wherein the doped diamond layer is applied to a cobalt-containing hard metal surface.

21. The method according to claim 16 , wherein the doped diamond layer and the undoped diamond layer are applied to a metal surface by chemical vapor deposition (CVD) from a methane/hydrogen atmosphere in a CVD chamber, wherein a coating temperature of between 800° C. and 1100° C. and a coating pressure of between 1 kPa and 100 hPa is set.

22. The method according to claim 16 , wherein the doping of the doped diamond layer is created by supply of a doping gas during chemical vapor deposition in a CVD chamber.

23. The method according to claim 16 , wherein the undoped diamond layer is created by interruption of supply of a doping gas into a CVD chamber.

24. A method as recited in claim 16 , wherein the method further comprises reducing a cutting speed of the machining tool upon determining that the measurement parameter passes the predefined threshold value.

25. A method as recited in claim 16 , wherein the method further comprises re-coating the machining tool with an undoped diamond layer after determining that the measurement parameter has passed the predefined threshold value.

26. A method as recited in claim 16 , wherein the method further comprises irradiating an undoped polycrystalline diamond layer with an ion beam to form the doped diamond layer.

27. A method as recited in claim 16 , wherein the method further comprises pre-germinating a surface of the metallic substrate layer by dusting the metallic substrate layer with diamond powder.

28. A method as recited in claim 16 , wherein the method further comprises irradiating a surface of the metallic substrate layer with an ion stream of nitrogen ions.

29. A method for continuously detecting the degree of wear of an undoped diamond layer, which forms a functional region of a machining tool, and which is arranged on a diamond layer doped with foreign atoms, during operation of the tool; wherein
a) the doped diamond layer is arranged directly on the substrate surface of the machining tool;
b) at least one measurement parameter, which results from both diamond layers, the tool, and a workpiece machined with the tool, is detected continuously or periodically during the operation of the tool;
c) predefined threshold value for the measurement parameter is specified; and wherein
d) a change of the measurement parameter above or below the predefined threshold value indicates the degree of wear of the undoped diamond layer, wherein:
the doped diamond layer and the undoped diamond layer are applied to a metal surface by chemical vapor deposition (CVD) from a methane/hydrogen atmosphere in a CVD chamber, wherein a coating temperature of between 800° C. and 1100° C. and a coating pressure of between 1 kPa and 100 hPa is set, and
a W-wire is used as a heating wi

Assignees

• Guehring Kg

Inventors

• Garrn Immo

Classifications

• C23C16/278

  doping or introduction of a secondary phase in the diamond · CPC title

• C23C16/277

  using other elements in the gas phase besides carbon and hydrogen; using other elements besides carbon, hydrogen and oxygen in case of use of combustion torches; using other elements besides carbon, hydrogen and inert gas in case of use of plasma jets · CPC title

• C23C28/044

  coatings specially adapted for cutting tools or wear applications · CPC title

• B23Q17/0995 Primary

  Tool life management · CPC title

• B23Q17/0952

  during machining · CPC title