Cutting Tool Holder Groove Angles for Stable Chip Evacuation
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Solution Overview
Problem
Conventional cutting tool holders with inner and outer inserts for drilling processes face instability in chip flow due to differences in chip shape and direction, leading to potential damage to the machined surface and inaccurate results.
Innovation Solution
A cutting tool holder design featuring a bar-shaped main body with spirally extending grooves and pockets for inserts, where the first groove has a smaller angle with the outer peripheral surface compared to the second groove, stabilizing the flow of chips generated by the inner insert and preventing them from flying outward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional chip discharge grooves are used for both inner and outer inserts, then the structure is simple, but chip flow becomes unstable due to different chip shapes
Solution Approach 1:
The patent applies local quality by configuring different groove structures for different insert positions. The first groove (for inner insert) has a smaller angle θ1 with the outer peripheral surface, while the second groove (for outer insert) has a larger angle θ2. This localized differentiation addresses the different chip characteristics generated at each insert position, stabilizing chip flow without requiring complete structural redesign.
Solution Approach 2:
The patent employs asymmetry by making the groove angles asymmetric relative to the rotation axis. The first groove opens at angle θ1 and the second groove opens at angle θ2, where θ1 < θ2. This asymmetric configuration optimizes chip discharge for each insert's specific cutting conditions, preventing chip accumulation and flow instability that would occur with symmetric conventional grooves.
2Productivity
If inner insert generates long spiral chips, then cutting action is effective, but chips fly outward and damage workpiece surface
Solution Approach 1:
The patent changes the geometric parameter of the groove configuration to control chip flow. By setting the first groove's angle θ1 smaller than the second groove's angle θ2, the groove geometry is optimized to contain and guide long spiral chips generated by the inner insert, preventing them from flying outward and damaging the workpiece surface while maintaining effective cutting action.
Solution Approach 2:
The first groove acts as an intermediary structure between the inner insert and the workpiece environment. It captures and channels the long spiral chips generated by the inner insert, providing a controlled path for chip evacuation that prevents direct contact between chips and the workpiece surface, thus eliminating the harmful effect while preserving cutting effectiveness.
3Reliability
If chips flow unstably, then evacuation is difficult, but increasing groove angle may help, it complicates the groove design
Solution Approach 1:
The patent resolves this contradiction by applying local quality - different groove angles are assigned to different locations based on local chip characteristics. The first groove has angle θ1 optimized for inner insert chips, while the second groove has angle θ2 optimized for outer insert chips. This localized optimization achieves stable chip flow without requiring uniform complexity throughout the entire groove system.
Solution Approach 2:
The asymmetric groove angle configuration (θ1 < θ2) provides a straightforward design solution that achieves stable chip flow. Rather than complicating the overall groove design with additional components or mechanisms, the patent uses simple asymmetric angular differentiation to stabilize chip evacuation, maintaining design simplicity while improving reliability.
Data Source
AI summary
A cutting tool holder of the present disclosure includes a bar-shaped main body. The main body includes a first pocket to receive a first insert, a second pocket to receive a second insert, a first groove extending from the first pocket, and a second groove extending from the second pocket. The first groove includes a second opening located on a rear side in a rotation direction, and the second groove includes a fourth opening located on a rear side in the rotation direction in a cross section orthogonal to a rotation axis. An angle θ1 formed by the second opening and an outer peripheral surface of the main body is smaller than an angle θ2 formed by the fourth opening and the outer peripheral surface of the main body in a cross section orthogonal to the rotation axis.