Geometric Compensation for Drill Bit Sintering Shrinkage
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Solution Overview
Problem
Conventional earth-boring drill bits face challenges in maintaining accurate positioning of cutting element pockets due to shrinkage during the sintering process, leading to performance issues such as early failure and dynamic stability problems.
Innovation Solution
The use of geometric compensation techniques to non-uniformly scale features in less than fully sintered bit bodies, accounting for expected shrinkage, allows for precise placement of cutting element pockets to their desired final positions, ensuring accurate drilling profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If powder compaction and sintering techniques are used to form bit bodies, then manufacturing precision and material performance are improved, but positional accuracy of cutting element pockets deteriorates due to shrinkage during sintering
Solution Approach 1:
The patent applies preliminary action by pre-compensating for shrinkage in the green bit body dimensions and feature positions before sintering. Geometric compensation factors are calculated and applied to scale the green bit body geometry, so that after uniform shrinkage occurs during sintering, the final sintered bit body achieves the desired dimensional accuracy and feature positioning without requiring post-sintering adjustments.
Solution Approach 2:
The patent utilizes parameter changes by modifying the green bit body geometric parameters (dimensions and feature positions) based on calculated compensation factors. These parameter adjustments account for the predictable uniform shrinkage that will occur during sintering, ensuring that the final sintered bit body achieves the target dimensional accuracy and feature positioning.
2Manufacturing precision
If uniform shrinkage compensation is applied to green bit body dimensions, then overall dimensional accuracy is improved, but non-uniform shrinkage causes residual positional errors in features
Solution Approach 1:
The patent applies local quality by differentiating the compensation approach for different regions and features of the bit body. Rather than applying a single uniform compensation factor, the patent calculates and applies specific geometric compensation factors tailored to different portions of the green bit body geometry, accounting for local variations in shrinkage behavior and feature positioning requirements.
Solution Approach 2:
The patent utilizes segmentation by dividing the green bit body geometry into multiple regions or feature groups that may experience different shrinkage characteristics. Each segment or feature group receives appropriate geometric compensation factors, allowing for more precise control over final feature positioning while maintaining overall dimensional accuracy.
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 significantly reduces positional errors of cutting element pockets, enhancing drill bit stability and performance by ensuring that cutting elements maintain their intended positions and functionality during drilling operations.
Implementation Method 1
The term 'sintering,' as used herein, means the densification of a particulate component and involves removal of at least a portion of the pores between the starting particles, accompanied by shrinkage, combined with coalescence and bonding between adjacent particles.
Data Source
Figure 1
Figure 2A~2D
Figure 2E
AI summary
Geometric compensation techniques are used to improve the accuracy by which features may be located on drill bits formed using particle compaction and sintering processes. In some embodiments, a positional error to be exhibited by at least one feature in a less than fully sintered bit body upon fully sintering the bit body is predicted and the at least one feature is formed on the less than fully sintered bit body at a location at least partially determined by the predicted positional error. In other embodiments, bit bodies of earth-boring rotary drill bits are designed to include a design drilling profile and a less than fully sintered bit body is formed including a drilling profile having a shape differing from a shape of the design drilling profile. Less than fully sintered bit bodies of earth-boring rotary drill bits are formed using such methods.