Shoulder Milling Insert Rake Geometry for Chip Evacuation
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Solution Overview
Problem
Chips formed during shoulder milling often get stuck or jammed between the cutting insert and the workpiece, leading to damage, particularly at small cutting depths, due to inadequate chip evacuation.
Innovation Solution
A trigonal cutting insert with a concave indentation in the corner and main rake surfaces, directing chips axially and promoting helical chip formation, reduces the risk of chip jamming by controlling the chip radius and evacuation path, especially at small cutting depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cutting inserts with flat rake surfaces are used, then the structure is simple and easy to manufacture, but chips get clamped between the clearance surface and the machined surface, causing damage
Solution Approach 1:
The patent applies curvature by forming a concave indentation in the rake surface that follows the natural curvature of the chip. This concave shape allows the chip to curl and flow smoothly along the rake surface into the chip pocket, preventing chip clamping and jamming while maintaining structural simplicity
2Reliability
If conventional cutting inserts without chip flow control are used, then the device complexity is low, but chips jam on inactive cutting edges, causing damage
Solution Approach 1:
The patent applies local quality by creating a localized concave indentation specifically in the region where chips are most likely to jam (near the inactive cutting edges). This localized modification directs chips away from vulnerable areas without requiring complex changes to the entire insert structure
3Productivity
If low feed rates are used to avoid chip jamming, then chip evacuation is improved, but productivity decreases
Solution Approach 1:
The patent applies preliminary action by pre-forming the concave indentation in the rake surface before machining begins. This pre-configured geometry proactively guides chip flow and prevents jamming from occurring in the first place, allowing high feed rates to be used without experiencing chip evacuation problems
Data Source
AI summary
A trigonal cutting insert for a shoulder milling tool includes an upper side, an opposite lower side and a peripheral side surface. A plurality of indexable cutting edges extend along corners of the cutting insert, each cutting edge having a main cutting edge, a corner cutting edge, and a surface-wiping secondary cutting edge. The upper side includes a recessed central surface, and a plurality of positively inclined rake surfaces having a main rake surface portion, a corner rake surface portion, and a secondary rake surface portion. A concave indentation is formed in the corner rake surface portion and in at least an initial part of the main rake surface portion adjacent to the corner rake surface portion, wherein the concave indentation has an elongated shape.