Multi-Step Twist Drill Point for Overlap-Free Cutting and Wear Control
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Solution Overview
Problem
Conventional twist drills with parallel step surfaces suffer from machining overlap, reduced cutting efficiency, and accelerated wear, leading to shorter service life due to increased cutting output.
Innovation Solution
A twist drill with a multi-step drill point featuring a spiral flute, a chisel edge, and a stepped groove with a decreasing pitch from the tip to the shank, which divides the cutting edge into sections and reduces the slope angle from 17° to 8°, enhancing cutting speed and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If parallel step surfaces are used in conventional twist drills, then the structure is simple and easy to manufacture, but machining overlap occurs and cutting efficiency is reduced
Solution Approach 1:
The patent applies spiral curved surfaces instead of parallel flat step surfaces. The spiral flutes and stepped grooves create curved cutting paths that eliminate machining overlap between steps, thereby improving cutting efficiency while maintaining manufacturability through standard spiral flute formation processes.
Solution Approach 2:
The patent transitions from two-dimensional parallel step surfaces to three-dimensional spiral stepped grooves. By adding the spiral dimension along the drill length, the cutting edges engage the workpiece in a progressive manner without overlap, resolving the efficiency problem while keeping the structure manufacturable.
2Speed
If spiral cutting flute with increasing pitch is used, then cutting speed is greatly increased, but cutting output increases and accelerates wear reducing service life
Solution Approach 1:
The patent applies different pitch characteristics to different sections of the spiral flute. The pitch gradually increases from the tip toward the shank, creating local variations in cutting output. This allows high cutting speed at the tip while distributing wear more evenly along the length of the drill, extending service life.
Solution Approach 2:
The patent changes the pitch parameter of the spiral flute along its length rather than maintaining a constant pitch. This gradual parameter change optimizes the balance between cutting speed and cutting output, preventing excessive wear while maintaining high efficiency.
3Duration of action of moving object
If stepped groove with decreasing pitch is used, then wear is reduced and service life is extended, but cutting speed may be limited
Solution Approach 1:
The patent divides the cutting edge into multiple sections using stepped grooves with decreasing pitch. This segmentation creates multiple cutting zones that work in sequence, allowing the drill to maintain high cutting speed while distributing the cutting load to reduce wear on any single section, thereby extending service life.
Data Source
AI summary
A twist drill with a multi-step drill point includes a shank and a cutting portion. The cutting portion is provided with a spiral flute and a body clearance. A tip of the cutting portion is provided with a chisel edge and a cutting edge. A flank face connected with the cutting edge is provided with a stepped groove which divides the cutting edge into several sections. A pitch of the stepped groove gradually decreases along a direction from the tip of the cutting portion to the shank.