Convex Cutting Insert Geometry for Lower Chatter at Cut Entry
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Solution Overview
Problem
Cutting inserts experience significant chatter vibration and increased cutting resistance when starting to cut into a work material, particularly due to the large impact and prolonged contact length, which can lead to tool damage.
Innovation Solution
A cutting insert design featuring a main cutting edge with an upwardly convex curved shape and paired linear portions, where the top portion is positioned closer to the first corner cutting edge contiguous to the work material, reducing the contact length and impact, and incorporating a bent part to reduce cutting angle and chip thickness, thereby controlling cutting resistance and suppressing chatter vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the cutting edge has a linear shape, then the total length of the cutting edge is short, but the contact length with the work material becomes long and chatter vibration increases
Solution Approach 1:
The cutting edge is designed with a curved shape instead of a linear shape. Specifically, the cutting edge includes a first curved portion and a second curved portion that are symmetric with respect to a reference line, creating a non-linear geometry that reduces chatter vibration while maintaining an appropriate total length. This curvature allows the cutting edge to engage the work material in a way that distributes contact more favorably, reducing the harmful effects of prolonged contact.
2Ease of operation
If the cutting edge has an upwardly convex curved shape, then chatter vibration is reduced, but the total length of the cutting edge becomes long and cutting resistance increases
Solution Approach 1:
The cutting edge employs a curved geometry with specific constraints on the total length. The curve is designed to reduce chatter vibration through its non-linear engagement with the work material, while the total length is controlled to prevent excessive cutting resistance. The curvature radius and overall dimensions are optimized to balance vibration reduction with acceptable cutting forces.
Solution Approach 2:
The design specifies particular parameter ranges for the cutting edge, including the total length and curvature characteristics. By controlling these geometric parameters within defined ranges, the invention achieves optimal performance where chatter vibration is suppressed without incurring excessive cutting resistance. The parameter optimization ensures that the curved shape provides vibration damping benefits while maintaining efficient material removal.
3Productivity
If the entire ridge of the cutting edge strikes the end surface of the work material, then cutting starts quickly, but large impact is applied and chatter vibration is generated
Solution Approach 1:
The curved shape of the cutting edge modifies the engagement pattern with the work material during the start of cutting. Instead of the entire ridge striking the end surface simultaneously, the curvature creates a progressive engagement where different portions of the cutting edge contact the work material at different times. This distributes the impact over a longer period, reducing peak forces and minimizing chatter vibration while still achieving rapid cutting initiation.
Data Source
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AI summary
This cutting insert is provided with a lower surface of polygonal shape including side parts and a pair of corner parts, an upper surface, a lateral surface situated between the lower surface and the upper surface, a pair of corner cutting edges located at the pair of corners at a line of intersection of the upper surface and the lateral surface, and a main cutting edge located in a side portion at a line of intersection of the upper surface and the lateral surface. The main cutting edge is upwardly convex in shape, and in side view includes an upwardly convex curving portion, and a pair of linear portions respectively extending toward the pair of corner cutting edges from the curving portion. The top portion of the curving portion is positioned more toward the one of the corner cutting edges which, of the pair of corner cutting edges, is that contiguous to the working surface of the work material during cutting of the work material.