Superhard Wear Part Bonding With a Profiled Metal Interlayer
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Solution Overview
Problem
Ceramic, cermet, and superhard materials are difficult to machine, bond, and join due to their hardness, brittleness, and poor wettability, making it challenging to secure them within tool components with precise tolerances and at high temperatures, especially when used in abrasive applications.
Innovation Solution
A tool component design featuring a wear part covered by a connection member, where the connection member is pressed to follow the profile of the wear part, providing a thin layer that co-operatively shapes with the wear part to prevent relative movement, and can be bonded using methods like brazing or soldering, even for materials with high thermal instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional joining methods (welding, brazing, soldering) are used to attach wear parts to tool bodies, then strong bonding is achieved, but the process becomes difficult or impossible due to poor wettability and brittleness of ceramic/superhard materials
Solution Approach 1:
The patent introduces a metal connection member as an intermediary between the ceramic/superhard wear part and the tool body. This connection member has a first surface that mechanically engages with the wear part (through pressing to follow its profile) and a second surface that can be conventionally joined to the tool body, thereby mediating the joining process and avoiding direct contact between incompatible materials.
Solution Approach 2:
The joining system is segmented into three distinct components: the wear part, the connection member, and the tool body. This segmentation allows each component to be optimized independently - the wear part for wear resistance, the connection member for joining compatibility, and the tool body for structural function - thereby resolving the contradiction between bonding strength and ease of manufacture.
2Strength
If shrink fitting is used to secure wear parts, then strong mechanical attachment is achieved, but the brittle wear part may fracture during the process
Solution Approach 1:
The connection member acts as a cushioning element between the tool body and the brittle wear part. When mechanical attachment forces are applied, the connection member absorbs and distributes these forces, preventing concentrated stresses that would cause fracture of the wear part, while still providing strong overall attachment.
3Strength
If high temperature joining techniques are used, then strong bonding is achieved, but thermal instability of the wear part causes degradation
Solution Approach 1:
The connection member serves as a thermal buffer, allowing the tool body to be joined at high temperatures while protecting the thermally unstable wear part from direct exposure to these temperatures. The connection member withstands the thermal conditions that would degrade the wear part, enabling strong bonding without thermal degradation.
4Manufacturing precision
If machining and finishing operations are performed on wear parts to achieve tight tolerances, then precise fit is achieved, but the hard material becomes difficult and expensive to machine
Solution Approach 1:
The manufacturing process is segmented into two stages: first, the wear part is manufactured in near-net shape without expensive machining; second, the connection member is used to achieve the precise final fit and alignment. This segmentation avoids the need to machine the hard wear part to tight tolerances, reducing manufacturing difficulty and cost.
Solution Approach 2:
The invention changes the approach from achieving precision through material removal (machining) to achieving precision through a combination of near-net-shape manufacturing and a compliant connection member that can be pressed to follow the wear part's profile, thereby accommodating minor dimensional variations.
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 design effectively secures hard and brittle wear parts within tool bodies, ensuring operational stability and preventing damage, while allowing for bonding techniques that accommodate thermal expansion differences and surface irregularities, enhancing the durability and reliability of the tool components.
Implementation Method 1
at least part of the connection member having been pressed against at least part of the surface of the wear part such that a surface of the connection member that faces a surface of the wear part follows the profile of the said part of the surface of the wear part against which it has been pressed
Data Source
Figure 1~3
Figure 4a~4d
Figure 4e~4r
AI summary
A tool component comprising a wear part covered at least in part by a connection member, the wear part having a specified hardness and the connection member being a metal or alloy, and the wear part comprising a surface that includes one or more depressions or projections therefrom, and the connection member having been pressed against that surface so that at least the surface of the connection member that faces the wear part surface follows the profile of the wear part, whereby relative movement between the wear part and connection member is substantially prevented. The metal or alloy connection member may be readily attached to a tool body for example by brazing of the like. The wear part may comprise a material that is not readily brazeable, for example a ceramic material or a cermet or a superhard material or a composite of such materials.