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 designed with multiple cutting edges on each step section, where at least one cutting edge is formed in a multi-segment style and another in a one-segment style, allowing for a compound cutting effect that reduces cutting force per unit edge length and disperses heat, with each cutting edge segment having distinct angles and radial positions to enhance cutting efficiency.
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 cutting force is high and processing efficiency is low
Solution Approach 1:
The cutting edge is divided into multiple segments (first cutting edge segment and second cutting edge segment) with different geometric parameters. Each segment has distinct entering angles and auxiliary angles, allowing the cutting edge to engage the workpiece in stages, reducing instantaneous cutting force while maintaining overall cutting effectiveness.
Solution Approach 2:
Different segments of the cutting edge are given different local properties through varying geometric parameters. The first cutting edge segment has different entering and auxiliary angles compared to the second cutting edge segment, optimizing cutting performance at different stages of the cutting process and reducing overall cutting force.
2Temperature
If traditional step drill bit with one-segment cutting edge is used, then manufacturing is simple, but cutting sharpness is insufficient and heat dissipation is poor
Solution Approach 1:
The cutting edge is segmented into multiple sections with different geometric parameters. This segmentation creates multiple cutting surfaces that distribute heat generation across different zones, improving heat dissipation. The distinct entering and auxiliary angles of each segment facilitate better chip evacuation and heat management during cutting operations.
3Object-generated harmful factors
If traditional step drill bit design is used, then chip breaking is difficult due to high cutting forces, but simpler design would reduce processing capability
Solution Approach 1:
The cutting edge is divided into multiple segments that engage the material progressively. This segmentation reduces the instantaneous cutting force on any single point, making chip formation and breaking easier. The different geometric parameters of each segment help control chip flow and reduce chip entanglement, facilitating chip evacuation without compromising material processing capability.
Data Source
AI summary
The present invention relates to a step drill bit, characterized in that the step drill bit has 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, wherein, the at least two cutting edges on at least one of the step sections at least comprise a first cutting edge and a second cutting edge, wherein the first cutting edge and the second cutting edge are respectively constructed in at least two-segment style, and therefore respectively include at least two cutting edge segments, wherein the first cutting edge and the second cutting edge are at least partially different from each other in the structure of their cutting edge segments, or one cutting edge of the first cutting edge and the second cutting edge is formed in one-segment style, while the other cutting edge is formed in at least two-segment style, and thus includes at least two cutting edge segments. The present invention further relates to a method for drilling a workpiece by using a step drill bit.