Non-Planar Cutting Element Interface for Tensile Stress Relief

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Solution Overview

Problem

Existing downhole cutting tools, such as drag bits, face challenges in maintaining the integrity and effectiveness of ultrahard cutting layers due to tensile stresses, which can lead to premature failure and reduced drilling efficiency.

Innovation Solution

The implementation of a cutting element with a non-planar ultrahard layer and substrate interface design, featuring a compressive stress hoop and depressions near the peripheral edge, which redistributes compressive stresses and reduces tensile stresses, enhancing the durability and performance of the cutting elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a planar interface design is used between the ultrahard layer and substrate, then the manufacturing process is simple, but tensile stresses develop leading to premature failure and reduced tool life

Engineering Contradiction:

Improvetool lifeVSAvoidinterface design complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies curvature to the interface between the ultrahard layer and substrate by creating a non-planar, contoured surface. This curved interface design redistributes stresses uniformly across the bonding area, eliminating tensile stress concentrations that would cause premature failure. The contoured surface transforms the stress distribution pattern from concentrated to distributed, thereby extending tool life without adding significant manufacturing complexity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Strength

If the ultrahard layer is made thicker to improve durability, then cutting edge strength increases, but tensile stresses increase leading to delamination and failure

Engineering Contradiction:

Improvecutting edge strengthVSAvoidresistance to delamination

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The contoured interface design allows the ultrahard layer to be made thicker for improved cutting edge strength while preventing delamination. The curved surface distributes the additional weight and stress loads uniformly, preventing tensile stress concentrations at the interface that would cause delamination in conventional planar designs.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the interface from planar to contoured, fundamentally altering the stress distribution characteristics. This parameter change enables the ultrahad layer to maintain higher thickness for strength while the modified interface geometry prevents the tensile stress buildup that would otherwise cause delamination.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional planar cutting elements are used, then manufacturing is straightforward, but cutting efficiency decreases due to stress-induced premature failure

Engineering Contradiction:

Improvedrilling efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The contoured interface design improves drilling efficiency by preventing premature failure through stress redistribution. While the manufacturing process becomes slightly more complex, the extension of tool life and maintenance of cutting performance significantly boosts overall productivity. The curved interface can be manufactured using standard contouring techniques available in modern manufacturing.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 non-planar interface design improves the durability and cutting efficiency of downhole tools by reducing tensile stresses, leading to extended tool life and improved drilling performance.

Implementation Method 1

a compressive stress hoop extending around the upper surface adjacent the peripheral edge, extending into the at least one depression, and configured to reduce tensile stress in the ultrahard layer

Methodology Applied

Scientific EffectStress redistribution:

Data Source

PatentUS20260022613A1Cutting element with non-planar interface design and tools incorporating such elements

Publication Date: 2026.01.22 SCHLUMBERGER TECH CORP

AI summary

A cutting element may include a substrate having a non-planar upper surface with a peripheral edge, and an ultrahard layer. The upper surface may include at least one depression formed at least proximate the peripheral edge; and a compressive stress hoop extending around the upper surface adjacent the peripheral edge, extending into the at least one depression, and configured to reduce tensile stress in the ultrahard layer. The ultrahard layer may be on the substrate and may have a non-planar top surface and an interface formed between the ultrahard layer and the substrate.