Pick Tool Strike Tip Dome Interface and Apex Radius
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Solution Overview
Problem
Existing pick tools with super-hard tips face challenges in wear resistance and fracture, particularly due to the distribution of load across a greater surface area, leading to premature failure under impact energies.
Innovation Solution
A pick tool with a strike tip featuring a dome-shaped interface boundary and a strike structure comprising polycrystalline diamond (PCD) material bonded to a cobalt-cemented tungsten carbide substrate, where the strike end has a rounded apex with a specific radius of curvature and thickness, and includes filler material within the interstices of the PCD, enhancing wear resistance and fracture toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a sharper, more pointed apex is used, then the tool penetrates deeper into the body being degraded, but the load is distributed across a greater surface area causing the super-hard material to fail in shear/bending at lower impact energies
Solution Approach 1:
The patent applies parameter changes by optimizing the apex radius of curvature to a specific range (3.2-6.0 mm) and controlling the thickness parameter (2.5-10 mm) to achieve the optimal balance between penetration capability and fracture resistance. This quantitative parameter optimization resolves the contradiction by finding the precise values that maximize both penetration force and impact energy resistance.
Solution Approach 2:
The patent uses composite materials by bonding super-hard material (PCD or cBN) to a cemented carbide substrate, creating a composite structure that combines the high hardness and wear resistance of the super-hard material with the high toughness and impact strength of the carbide substrate. This composite construction allows the tool to achieve both deep penetration and high fracture resistance.
2Strength
If a blunter apex is used, then the tool provides better buttress support to the diamond substrate, but the tool breaks at much lower impact energies due to load distribution across greater surface area
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the apex radius of curvature parameter within 3.2-6.0 mm, which provides sufficient buttress support while avoiding excessive surface area that would cause premature failure under impact loading.
3Ease of manufacture
If the interface boundary is planar, then the manufacturing process is simpler, but the bond strength and load distribution are inferior compared to a dome-shaped interface
Solution Approach 1:
The patent applies spheroidality by forming a dome-shaped interface boundary with a specific radius of curvature (5-20 mm) between the super-hard material and the carbide substrate. This curved interface distributes mechanical loads more evenly across the bonding area compared to a planar interface, significantly improving bond strength and reducing stress concentration at the interface.
4Reliability
If filler material is added to the PCD material, then wear resistance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent uses composite materials by incorporating filler material (such as cobalt, iron, nickel, or manganese) within the polycrystalline diamond structure to create a composite PCD material. This composite construction improves wear resistance while the filler material serves multiple functions including strengthening the diamond grain boundaries and providing catalytic activity for diamond growth during synthesis.
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 solution significantly improves the working life of the pick tool by reducing the risk of fracture and wear, allowing for higher force requirements to break materials and maintaining efficiency in road milling and mining operations, while being easier to manufacture with reduced sinter defects.
Implementation Method 1
the strike structure comprising polycrystalline diamond (PCD) material... significantly improves the working life of the pick tool by reducing the risk of fracture and wear
Implementation Method 2
the interface boundary being dome-shaped and being free of a central depression... the distribution of the load across a greater surface area
Implementation Method 3
the strike end including a rounded apex having a radius of curvature in a longitudinal plane of at least 3.2 mm and at most 6 mm
Implementation Method 4
the strike structure may comprise PCD material comprising diamond grains having a mean size of at least about 15 microns... filler material within the interstices between diamond grains
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A strike tip for a pick tool, comprising a strike structure joined to a substrate at an interface boundary, the strike structure comprising super-hard material and the substrate comprising carbide material. The strike structure has a strike end opposite the interface boundary, the strike end including a rounded apex having a radius of curvature in a longitudinal plane of at least 3.2mm and at most 6mm.