Non-cylindrical Polycrystalline Diamond Compacts Without Undercutting
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Solution Overview
Problem
Conventional polycrystalline diamond compacts (PDCs) often undergo significant undercutting during electro-discharge machining (EDM) to form non-cylindrical geometries, which depletes the cementing constituent and reduces brazeability, leading to suboptimal performance in applications like rotary drill bits.
Innovation Solution
The method involves forming non-cylindrical PDCs through a high-pressure/high-temperature (HPHT) process without substantial undercutting of the cemented carbide substrate, using a precursor PDC with a PCD table and a substrate having a non-cylindrical lateral periphery, and subsequent finish machining to achieve precise dimensions, thereby maintaining the integrity of the cementing constituent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If electro-discharge machining (EDM) is used to form non-cylindrical geometries in conventional PDCs, then the desired non-cylindrical shape is achieved, but significant undercutting occurs which depletes the cementing constituent and reduces brazeability
Solution Approach 1:
The invention performs preliminary shaping during the HPHT formation process itself, creating a precursor PDC with non-cylindrical geometry that closely matches the final desired shape. This preliminary action eliminates the need for subsequent aggressive EDM operations that would cause undercutting and deplete the cementing constituent, thereby preserving brazeability.
Solution Approach 2:
The invention replaces the mechanical EDM process with a controlled HPHT formation process that directly creates the non-cylindrical geometry. By substituting the mechanical removal process (EDM) with a formation process (HPHT), the harmful undercutting effect is eliminated while achieving the desired shape.
2Shape
If electro-discharge machining (EDM) is used to create non-cylindrical PDCs, then the desired shape is achieved, but the cementing constituent is depleted, leading to reduced performance
Solution Approach 1:
The non-cylindrical geometry is preliminarily formed during the HPHT process before any machining operations. This preliminary shaping action ensures that the cementing constituent is not subsequently removed by EDM, preventing depletion and maintaining the integrity of the PDC structure.
Solution Approach 2:
The invention substitutes the mechanical EDM process with an HPHT formation process that creates the non-cylindrical shape directly. This substitution prevents the mechanical removal of material that would deplete the cementing constituent, thereby preserving the substance and performance of the PDC.
3Productivity
If conventional PDC fabrication with subsequent EDM machining is used, then non-cylindrical PDCs are produced, but substantial undercutting occurs affecting substrate integrity
Solution Approach 1:
The HPHT process preliminarily forms the non-cylindrical geometry with high precision, creating a precursor PDC that requires minimal subsequent machining. This preliminary action ensures that the substrate integrity is maintained by avoiding the substantial undercutting that would occur with aggressive EDM operations.
Solution Approach 2:
The invention replaces the mechanical EDM machining system with an HPHT formation system that directly creates the non-cylindrical geometry. This substitution eliminates the harmful undercutting effect on the substrate while maintaining manufacturing productivity, as the shaping occurs during the formation process itself.
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 prevents substantial undercutting and maintains the brazeability of the cemented carbide substrate, enhancing the performance and durability of non-cylindrical PDCs in applications such as rotary drill bits and other mechanical apparatuses.
Implementation Method 1
The substrate(s) and volume of diamond particles are then processed under HPHT conditions in the presence of a catalyst material that causes the diamond particles to bond to one another to form a matrix of bonded diamond grains
Implementation Method 2
The diamond table is formed and bonded to a substrate in a high-pressure/high-temperature ("HPHT") process
Implementation Method 3
a constituent of the cemented-carbide substrate, such as cobalt from a cobalt-cemented tungsten carbide substrate, liquefies and sweeps from a region adjacent to the volume of diamond particles into interstitial regions between the diamond particles during the HPHT process
Implementation Method 4
The method further includes finish machining at least the substrate non-cylindrical lateral periphery to form the finished PDC
Data Source
AI summary
Embodiments of the invention relate to non-cylindrical polycrystalline diamond compacts (“PDCs”), and methods of fabricating such non-cylindrical PDCs without substantially undercutting a cemented carbide substrate thereof from an overlying polycrystalline diamond (“PCD”) table thereof. According to various embodiments, a PDC includes a PCD table including an upper surface and a table non-cylindrical lateral periphery. The PDC includes a cemented carbide substrate bonded to the PCD table. In an embodiment, the cemented carbide substrate includes a substrate non-cylindrical lateral periphery that is not substantially undercut from the table non-cylindrical lateral periphery of the PCD table. In an embodiment, the PDC includes at least one alignment feature positioned on the cemented carbide substrate and/or the PCD table.