Stepped Joint Cutting Insert for Heat-Resistant Brazing
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Solution Overview
Problem
Cutting inserts for high hardness material machining face issues with braze material softening due to high temperatures during machining, leading to potential separation or fracture of the sintered body from the base body, and the sintered body is expensive, necessitating size reduction.
Innovation Solution
A cutting insert design featuring a sintered body with a step-like joint surface configuration, where the leading side of the joint is lower than the trailing side, minimizing thermal softening of the braze material and increasing the joint area for enhanced strength, while allowing for a thinner sintered body and reduced material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sintered body is joined to the base body with a braze material in a conventional configuration, then the cutting insert can be assembled, but the braze material softens due to high temperature during machining under high load conditions, leading to separation or fracture
Solution Approach 1:
The patent introduces a step-like configuration to the joint surface, transforming it from a flat two-dimensional surface to a three-dimensional stepped structure. This dimensional change creates multiple levels (first and second joint surfaces at different heights) that redistribute the thermal and mechanical loads, preventing direct heat transmission from the cutting edge to the braze material while maintaining structural integrity.
Solution Approach 2:
The joint surface is segmented into multiple distinct surfaces (first joint surface, second joint surface, and intermediate connecting surface) rather than being a single continuous surface. This segmentation allows different portions of the joint to experience different temperature and stress conditions, with the stepped structure creating thermal barriers that protect the braze material from excessive heat.
2Strength
If the sintered body is made larger to increase joint area and strengthen the brazed joint, then the joint strength improves, but the cutting insert becomes more expensive due to increased material usage
Solution Approach 1:
By transitioning from a flat joint surface to a stepped three-dimensional structure, the patent increases the effective joint area without proportionally increasing the volume of the sintered body. The vertical dimension is utilized to create additional joint surfaces (first and second joint surfaces at different levels), allowing greater bonding area with minimal material addition.
Solution Approach 2:
The intermediate joint surface connecting the first and second joint surfaces features an upwardly convex curved shape. This curvature optimizes the stress distribution across the joint interface and maximizes the bonding area within the available space, enabling enhanced joint strength without requiring a larger sintered body volume.
3Strength
If the joint surface is positioned closer to the cutting edge for better structural support, then the structural support improves, but the braze material undergoes thermal softening due to proximity to the high-temperature cutting zone
Solution Approach 1:
The stepped configuration utilizes the vertical dimension to create multiple joint surfaces at different heights relative to the cutting edge. The first joint surface is positioned closer to provide structural support, while the second joint surface is positioned higher to be farther from the heat source, creating a thermal gradient that protects the braze material from excessive temperatures.
Solution Approach 2:
The stepped joint structure is designed in advance to anticipate and prevent thermal softening before it occurs. By positioning the second joint surface higher and farther from the cutting edge, the design preemptively creates a thermal barrier that prevents the braze material from reaching temperatures that would cause softening, rather than attempting to address the problem after thermal exposure begins.
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 step-like joint surface design effectively reduces thermal softening of the braze material, enhances brazing strength, and enables size reduction of the sintered body, thereby improving the durability and cost-effectiveness of the cutting insert.
Implementation Method 1
the braze material being softened by the heat conducted thereto from the cutting edge part of the sintered body that is heated to a high temperature during machining
Data Source
AI summary
A cutting insert that suppresses softening of joint material in a joint surface between a sintered body and a base body to improve the joint strength, and that enables size reduction of the sintered body, is provided. The cutting insert includes a sintered body having a cutting edge, and a base body having a leading end where the sintered body is joined via a braze material. The sintered body includes a front surface on a leading side, an upper surface connected to the front surface and forming the cutting edge with the front surface along a connecting edge with the front surface, a bottom surface opposite the upper surface, a back surface opposite the front surface, and two side surfaces. The sintered body and base body are joined together in a joint surface including the bottom surface and back surface of the sintered body. The joint surface in side view has a step-like shape with a leading side thereof being lower than a trailing side thereof.