cBN/PCD Cutting Tool Braze Joint for Stronger Tip Bonding
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Solution Overview
Problem
Existing cutting tools with cBN or PCD tips face challenges in achieving strong bonding with cemented carbide substrates, leading to limited tool life and performance in metal cutting applications.
Innovation Solution
A cutting tool design featuring a cBN or PCD cutting edge tip brazed to a cemented carbide supporting body with a specific braze joint composition, including a TiC layer, a Ni-Cu-Ti layer, and a Ag-Cu layer, providing enhanced bonding strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional braze material is used to bond cBN or PCD tip to cemented carbide supporting body, then the bonding strength is insufficient, but using a complex multi-layer braze joint structure improves bonding strength and tool life
Solution Approach 1:
The braze joint is divided into three distinct layers with specific functions: a first layer (10-400 nm) adjacent to the supporting body, a second layer (0.5-8 μm) in the middle, and a third layer (4-145 μm) adjacent to the cutting edge tip. Each layer has controlled thickness and composition to optimize bonding while managing complexity through functional segmentation.
Solution Approach 2:
The braze joint employs composite material structure combining different metallic elements (Ni, Cu, Ti, Ag) in specific layers. The supporting body contains WC grains with metallic binder (Ni, Fe, Co), while the braze joint layers contain specific combinations of these elements to create a composite structure that achieves superior bonding strength.
2Duration of action of stationary object
If the braze joint thickness is increased to improve bonding strength, then the tool life is extended, but the cutting tool geometry and precision are affected
Solution Approach 1:
The invention specifies precise thickness parameters for each braze joint layer: first layer 10-400 nm, second layer 0.5-8 μm, and third layer 4-145 μm. The total braze joint thickness is controlled at 5-150 μm. These parameter specifications ensure sufficient bonding strength while maintaining cutting tool geometry and precision by preventing excessive thickness that would compromise performance.
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 new braze joint configuration results in a cutting tool with improved bonding strength and extended tool life, capable of withstanding high cutting temperatures and forces, thus enhancing machining performance in metal cutting operations.
Implementation Method 1
a first layer of TiC situated next to the supporting body with an average thickness of 10-400 nm
Implementation Method 2
a second layer, with an average thickness of 0.5-8 μm, comprising in average at least 5 wt% metallic Ni, in average 25-60 wt% metallic Cu and in average 15-45 wt% metallic Ti
Implementation Method 3
a third layer, with an average thickness of 4-145 μm, comprising metallic Ag and metallic Cu
Implementation Method 4
the cBN, or PCD, cutting edge tip is attached to the supporting body via a 5-150 μm thick braze joint
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a cutting tool comprising a supporting body and a cBN, or PCD, cutting edge tip, wherein the cBN, or PCD, cutting edge tip is attached to the supporting body via a 5-150 µm thick braze joint, the supporting body is of cemented carbide comprising 3-25 wt% of a metallic binder, optionally up to 25 wt% of carbides or carbonitrides of one or more elements of group 4, 5, or 6 in the periodic table of elements, and rest WC, wherein the metallic binder comprises at least 40 wt% Ni, and wherein said braze joint comprises, in the order from the supporting body, a first layer of TiC situated next to the supporting body with an average thickness of 10-400 nm, a second layer, with an average thickness of 0.5-8 µm, comprising in average at least 5 wt% metallic Ni, in average 25-60 wt% metallic Cu and in average 15-45 wt% metallic Ti, and a third layer, with an average thickness of 4-145 µm, comprising metallic Ag and metallic Cu.