Earth-Boring Tool Cutting Element Pockets via Plasma Gouging

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Solution Overview

Problem

The existing methods for forming earth-boring tools with cutting elements secured in cutting element pockets face challenges due to the difficulty in machining hardfacing materials, which can damage polycrystalline diamond compact (PDC) cutting elements during the application of hardfacing, and require pre-forming cutting element pockets before applying the hardfacing material.

Innovation Solution

The method involves using a plasma spray device to gouge recesses through the hardfacing layer and into the body of the earth-boring tool, followed by machining to form cutting element pockets, allowing for secure placement of cutting elements within these pockets, even after hardfacing has been applied.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If hardfacing material is applied to the bit body to increase wear resistance, then the bit body gains increased hardness and wear resistance, but the high temperatures required to apply the hardfacing material cause damage to the diamond portion of PDC cutting elements

Engineering Contradiction:

Improvewear resistanceVSAvoidthermal damage to cutting elements

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The cutting element pockets are formed in the bit body before the hardfacing material is applied. This preliminary action allows the pockets to be created when the material is more easily machinable, avoiding thermal damage to cutting elements during hardfacing application while still enabling subsequent cutting element installation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of installing cutting elements before hardfacing (which would expose them to damaging temperatures), the method inverts the sequence by first forming empty pockets, then applying hardfacing, and finally installing cutting elements in the hardened bit body. This reversal eliminates thermal exposure of the diamond cutting elements

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If cutting element pockets are formed in the bit body before applying hardfacing material, then the pockets can be formed more easily, but temporary displacement members must be used to prevent the pockets from being filled with hardfacing material

Engineering Contradiction:

ImprovemachinabilityVSAvoidtemporary displacement members

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The method extracts and removes the temporary displacement members after the hardfacing material is applied and the pockets are formed. This allows the pockets to be created when machining is easier, while the displacement members are simply removed afterward to leave clean pockets for cutting element installation

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The displacement members are placed in the pockets as a preliminary measure during hardfacing application to prevent filling, then removed afterward. This temporary preliminary action enables the pockets to be formed at the optimal time for machining without permanent complexity

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional machining techniques are used to machine hardfacing material, then the process is straightforward, but the increased hardness of hardfacing material makes machining difficult

Engineering Contradiction:

Improvemachining easeVSAvoidmachining difficulty

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The cutting element pockets are formed in the bit body before the hardfacing material is applied, when the base material is more easily machinable. This preliminary machining action avoids the difficulty of machining the hardened surfacing material while still achieving precise pocket formation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of attempting to machine the hardfacing material after application (which is difficult due to increased hardness), the method inverts the sequence by forming pockets in the softer bit body first, then applying the hardfacing. This reversal makes the machining operation much easier while still achieving the desired result

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the formation of earth-boring tools with securely positioned cutting elements, enhancing wear resistance and maintaining the integrity of PDC cutting elements by allowing their placement after hardfacing, thus improving the tool's durability and performance.

Implementation Method 1

a plasma spray device is used to gouge at least one recess through the hardfacing layer and into the body using a plasma emitted by the plasma spray device

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentUS10000974B2Methods for forming earth-boring tools having cutting elements mounted in cutting element pockets and tools formed by such methods

Publication Date: 2018.06.19 BAKER HUGHES CO

AI summary

Methods of forming earth-boring tools include using a plasma spray device to gouge at least one recess through a hardfacing material and into a body. At least a portion of the recess may define a cutting element pocket in which a cutting element may be received and bonded. The recess formed using the plasma spray device optionally may be further machined to form the cutting element pocket. Earth-boring tools are fabricated using such methods.