Earth-Boring Tool Bodies via Injection Molding and Sintering
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Solution Overview
Problem
Existing methods for fabricating earth-boring tools face challenges in achieving desirable dimensional tolerances and using materials with high wear and erosion resistance, limiting the use of certain composite materials and manufacturing techniques.
Innovation Solution
The method involves injecting a powder mixture of hard particles, metal matrix particles, and an organic material into a mold cavity, applying pressure to form a green body, which is then sintered to create a fully dense body of an earth-boring tool, utilizing techniques like injection molding or transfer molding to overcome material limitations and achieve precise dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional infiltration fabrication techniques are used to fabricate bit bodies, then the manufacturing process is relatively simple, but the dimensional tolerances cannot meet tight requirements and certain composite materials cannot be successfully fabricated
Solution Approach 1:
The invention applies preliminary action by forming a green body with precise dimensional tolerances through injection molding before sintering. The mold cavity is designed with predetermined dimensional tolerances, and the green body is formed to match these tolerances before the sintering process, ensuring final dimensional accuracy without requiring complex post-processing or specialized fabrication techniques.
Solution Approach 2:
The invention utilizes parameter changes by transforming the physical state of materials from loose powder to a densely packed green body through controlled injection molding parameters. By adjusting injection pressure, temperature, and mold design parameters, the process achieves tight dimensional tolerances that conventional infiltration techniques cannot accomplish.
2Reliability
If materials with high wear and erosion resistance are used, then the tool performance is improved, but the materials are not easily machined using conventional techniques
Solution Approach 1:
The invention replaces conventional mechanical machining with injection molding and sintering processes. Instead of attempting to machine hard, wear-resistant composite materials using traditional cutting tools, the process forms the final geometry through mold cavity definition and controlled material deposition, eliminating machining difficulties entirely.
Solution Approach 2:
The invention changes the physical and chemical parameters of the material during processing. By controlling injection temperature, pressure, and cooling rates, the process forms green bodies from powder mixtures that contain hard particles dispersed in a metal matrix. These parameters are optimized to achieve both high wear resistance and dimensional accuracy without requiring subsequent machining.
3Manufacturing precision
If injection molding or transfer molding is used to form green bodies, then tight dimensional tolerances and high packing density are achieved, but the process complexity increases
Solution Approach 1:
The invention applies local quality by designing the mold cavity with specific surface finishes and geometric features that directly impart the desired surface quality and dimensional tolerances to the green body. The mold structure incorporates localized features such as cooling channels, ejection systems, and precision machining zones that enable high packing density and dimensional accuracy without requiring complex processing throughout the entire system.
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 enables the fabrication of earth-boring tools with improved wear and erosion resistance, meeting tight dimensional tolerances and facilitating large-scale production, even with challenging composite materials, by increasing packing density and reducing inter-particle friction during the molding process.
Implementation Method 1
applying pressure to form a green body
Implementation Method 2
increasing packing density
Implementation Method 3
the green body is then sintered to create a fully dense body of an earth-boring tool
Implementation Method 4
reducing inter-particle friction during the molding process
Data Source
AI summary
Methods of fabricating bodies of earth-boring tools include mechanically injecting a powder mixture into a mold cavity, pressurizing the powder mixture within the mold cavity to form a green body, and sintering the green body to a desired final density to form at least a portion of a body of an earth-boring tool. For example, a green bit body may be injection molded, and the green bit body may be sintered to form at least a portion of a bit body of an earth-boring rotary drill bit. Intermediate structures formed during fabrication of an earth-boring tool include green bodies having a plurality of hard particles, a plurality of matrix particles comprising a metal matrix material, and an organic material that includes a long chain fatty acid derivative. Structures formed using the methods of fabrication are also disclosed.