Segmented Step Drill Bit Geometry for Lower Cutting Force
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Solution Overview
Problem
Traditional step drill bits experience high cutting forces, insufficient sharpness, difficulty in chip breaking, and low processing efficiency due to their design, which results in excessive cutting heat and reduced material processing capabilities.
Innovation Solution
The step drill bit is redesigned with multiple cutting edges on each step section, featuring a combination of one-segment and multi-segment cutting edges, where each cutting edge segment can have different lengths and angles, allowing for a compound cutting effect that reduces cutting force and disperses heat, and the edges are arranged to merge their effects during rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional step drill bit design with single-segment cutting edges is used, then the structure is simple, but the cutting force is high and processing efficiency is low
Solution Approach 1:
The cutting edges are divided into multiple segments (first cutting edge segment and second cutting edge segment) with different entering/auxiliary angles. This segmentation allows each segment to engage the material at different angles, distributing the cutting force and improving material removal efficiency without requiring a complete redesign of the entire tool structure.
Solution Approach 2:
Different segments of the cutting edge are assigned different geometric properties (entering/auxiliary angles) to optimize their respective cutting functions. The first segment has one set of angles optimized for initial engagement, while the second segment has different angles optimized for continued material removal, creating local optimization along the cutting edge.
2Manufacturing precision
If traditional step drill bit with symmetrical single cutting edges is used, then the manufacturing is simple, but the cutting sharpness is insufficient
Solution Approach 1:
The cutting edge is designed with different segments having different entering/auxiliary angles to create varied local cutting characteristics. This local differentiation enhances the overall cutting sharpness by ensuring optimal angle engagement at different positions along the cutting path, while the segments are still formed on the same step section structure.
3Ease of operation
If traditional step drill bit design is used, then the tool structure is simple, but chip breaking is difficult
Solution Approach 1:
The segmented cutting edges create natural chip breaking points where the transition between segments causes chips to fracture. This segmentation effect facilitates chip evacuation without requiring additional chip breaking mechanisms or complex tool geometries.
4Temperature
If traditional step drill bit with single cutting edge per step section is used, then the heat generation is concentrated, but the structure is simpler
Solution Approach 1:
Dividing the cutting edge into multiple segments distributes the cutting action and heat generation across different segments. This segmentation allows heat to be dispersed over a larger area and duration, improving thermal management during the cutting process.
Data Source
AI summary
A step drill bit having a hole processing portion and at least two flutes extending on the hole processing portion, the hole processing portion comprising step sections, each step section and the at least two flutes forming at least two cutting edges distributed in a circumferential direction of the step section, each cutting edge having a tooth profile, wherein the first cutting edge and the second cutting edge are at least partially different from each other in the structure of their respective tooth profiles.