PDC Cutting Elements With Curved Stress-Reduction Features

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Solution Overview

Problem

Conventional cutting elements for earth-boring tools, particularly those with polycrystalline diamond compact (PDC) materials, suffer from spalling and cracking issues due to impact damage, leading to reduced effectiveness and premature wear, necessitating frequent replacement.

Innovation Solution

The cutting elements incorporate a curved stress-reduction feature with an undulating edge and a waveform extending towards the center longitudinal axis, along with recesses defined in the stress-reduction feature, which helps in mitigating shallow spall propagation and inducing beneficial stress states, thereby enhancing durability and cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional PDC cutting elements are used with flat cutting faces, then manufacturing is simple, but impact damage causes spalling and cracking that reduce lifespan

Engineering Contradiction:

Improvelifespan of cutting elementVSAvoidcomplexity of cutting face geometry

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The cutting face incorporates a curved stress-reduction feature with undulating edges and waveforms instead of a flat surface. This curvature redistributes impact forces across the cutting element, reducing peak stresses that cause spalling and cracking, thereby extending lifespan while adding geometric complexity

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cutting face features localized stress-reduction zones with varying curvature radii and waveform amplitudes in specific regions. These localized geometric modifications target areas most susceptible to impact damage, providing enhanced durability where needed while maintaining simpler geometry in other areas

Inventive Principle:

Principle #3Local quality

2Reliability

If cutting elements are designed to resist impact damage, then durability improves, but cooling efficiency may be compromised

Engineering Contradiction:

Improveresistance to impact damageVSAvoidcooling efficiency

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The curved stress-reduction feature creates a controlled porous or hollow structure within the cutting element body. This internal geometry provides channels for cooling fluid circulation, improving heat dissipation while the overall curved external shape maintains impact resistance by distributing external forces

Inventive Principle:

Principle #31Porous materials

3Strength

If recesses are added to the cutting face to mitigate spall propagation, then chip damage is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improveresistance to chip damageVSAvoidease of forming cutting face features

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The recesses are formed with curved surfaces and rounded edges that follow the overall waveform geometry, rather than sharp angular features. This curvature simplifies the manufacturing process by allowing form tools to create the recesses in a single operation and reduces stress concentration at recess boundaries, maintaining strength while improving manufacturability

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS10570668B2Cutting elements configured to reduce impact damage and mitigate polycrystalline, superabrasive material failure earth-boring tools including such cutting elements, and related methods

Publication Date: 2020.02.25 BAKER HUGHES CO

AI summary

A cutting element for an earth-boring tool includes a substrate and a polycrystalline, superabrasive material secured to an end of the substrate. The polycrystalline, superabrasive material includes a curved, stress-reduction feature located at least on the first transition surface. The cutting element includes at least one recess defined in the curved, stress-reduction feature of the polycrystalline, superabrasive material. The at least one recess includes sidewalls intersecting with a front surface of the stress-reduction feature of the polycrystalline, superabrasive material and extending to a base wall within the polycrystalline, superabrasive material. The curved, stress-reduction feature includes an undulating edge formed proximate a peripheral edge of the polycrystalline, superabrasive material and a waveform extending from the undulating edge toward the center longitudinal axis of the cutting element.