Cutter Pocket Machining After Hardfacing for Precise Earth-Boring Tools
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Solution Overview
Problem
Conventional earth-boring tool manufacturing processes result in heat-induced deformation and inaccuracies in cutting element pocket position and orientation, leading to compromised performance and variability in drilling stability and durability.
Innovation Solution
The method involves forming 'inverted' cutting element pockets in the tool body before thermal processing, followed by precise machining after hardfacing to ensure accurate positioning and orientation of cutting elements, using materials like polycrystalline diamond compact (PDC) and applying specific hardfacing materials to maintain tolerances and reduce distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional manufacturing processes are used to form cutting element pockets, then the tool body can be produced efficiently, but heat-induced deformation causes inaccuracies in cutting element pocket position and orientation
Solution Approach 1:
The patent applies preliminary action by forming the cutting element pockets in the tool body before thermal processing and hardfacing operations. By establishing the precise pocket locations and orientations in advance, the invention ensures that subsequent heating and coating processes cannot distort these critical features, thereby maintaining manufacturing precision while allowing efficient thermal processing for productivity.
2Duration of action of stationary object
If hardfacing material is applied to the tool body to reduce wear, then durability is improved, but heat from the process causes distortion of the tool body
Solution Approach 1:
The invention applies preliminary action by completing all precision machining of cutting element pockets before applying hardfacing material. This sequence ensures that the tool body achieves its final precise dimensions and orientations before undergoing thermal processing for durability, thereby preventing heat-induced distortion of critical features while still allowing hardfacing to be applied for wear resistance.
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 manufacturing tolerances, enhancing drilling stability, durability, and consistency across earth-boring tools, allowing for a larger range of stable penetration rates and improved performance compared to conventionally manufactured tools.
Implementation Method 1
Hardfacing materials may be applied by welding processes, e.g., plasma-transferred arc welding, oxygen-acetylene welding, gas metal arc welding
Implementation Method 2
or other deposition processes that cause heating of the tool body
Implementation Method 3
The tool body may also undergo thermal processing steps such as heat treatment prior to use of the earth-boring tool in a downhole environment
Data Source
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AI summary
A method of forming an earth-boring tool includes forming a tool body (102, 120) including at least one inverted cutting element pocket (122), at least a portion of the at least one inverted cutting element pocket (122) having a profile substantially matching a profile of an actual cutting element (106) to be secured within a cutting element pocket (108) to be formed by subsequently machining the at least one inverted cutting element pocket (122). Hardfacing material (126, 128) may be applied to portions of the tool body (102, 120). The actual cutting element pocket (108) is formed by removing material of the tool body (102, 120) within the at least one inverted cutting element pocket (122) subsequent to applying the hardfacing material (126, 128) to portions of the tool body (102, 120). A cutting element (106) is affixed within the actual cutting element pocket (108).