Mechanical Locking of Ultrahard Cutters in Carbide Matrix Bits

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Solution Overview

Problem

Conventional drilling systems face challenges in securely affixing ultrahard cutting elements to drill bits, as these materials are not brazable, leading to issues with durability and uptime during drilling through various formations.

Innovation Solution

A cutting assembly is created by mechanically connecting an ultrahard cutting device to a matrix using locking features, where the matrix is cured to apply compressive forces, providing a secure mechanical interlock that enhances retention and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ultrahard material is used for cutting elements, then cutting durability is improved, but the material cannot be brazed to the drill bit

Engineering Contradiction:

Improvecutting durabilityVSAvoidbrazability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

An intermediate material layer is introduced between the ultrahard cutting element and the drill bit body. This intermediate layer serves as a mediator that enables bonding: it is compatible with both the ultrahard material and the drill bit, allowing the cutting element to be securely attached without requiring direct brazing of the ultrahard material itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the thermal brazing process with a mechanical retention system. Locking features (such as recesses or protrusions) are formed on the lateral surface of the cutting element, which engage with corresponding features in the drill bit or matrix. This mechanical interlocking system substitutes for the brazing process, providing secure attachment while preserving the integrity of the ultrahard material.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If conventional affixing methods are used, then the cutting element can be attached to the drill bit, but retention and durability are insufficient during drilling

Engineering Contradiction:

Improveattachment capabilityVSAvoidretention durability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cutting element employs a composite structure combining multiple materials and retention mechanisms. The ultrahard cutting material is integrated with a matrix material that provides structural support and bonding. The combination of mechanical locking features and matrix embedding creates a composite assembly that achieves both ease of manufacture and high retention durability during drilling operations.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the cutting element is securely locked in the matrix, then retention is improved, but the structure becomes more complex

Engineering Contradiction:

Improveretention securityVSAvoidlocking structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is segmented into discrete, modular features formed on the lateral surface of the cutting element. These locking features (such as individual recesses or protrusions) are separate, well-defined elements that can be independently formed and engaged. This segmentation allows for reliable locking while maintaining manufacturing simplicity, as each feature can be created using standard machining or forming processes.

Inventive Principle:

Principle #1Segmentation

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

The solution improves the retention and durability of ultrahard cutting devices within the matrix, leading to increased drilling efficiency and extended tool life by translating thermal contraction into residual stresses that compress the cutting device, thereby enhancing its stability and performance.

Implementation Method 1

the matrix material may have a greater coefficient of thermal expansion than the ultrahard material. The thermal compression of the matrix during cooling from the curing process may apply a compressive force to a sidewall of the recess, thereby compressing the cutting device toward the matrix body

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentUS11492852B2Mechanical locking of cutting element with carbide matrix

Publication Date: 2022.11.08 SCHLUMBERGER TECH CORP

AI summary

A cutting device for use in a drill bit has a body including an ultrahard material. The body has a top surface, a front surface, and at least one lateral surface adjacent the top surface. The lateral surface is oriented at a surface angle relative to the top surface between 30 and 150 degrees. One or more locking features are located on the lateral surface.