Multi-Step Twist Drill Point With Variable Groove Pitch for Lower Wear
Find Innovative SolutionsGenerate Solutions
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, despite improvements in drilling performance and precision.
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 operation
If parallel step surfaces are used in conventional step twist drills, then positioning during layered drilling is improved, 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 spiral cutting edges create a curved geometry that eliminates machining overlap while maintaining positioning capability, directly resolving the contradiction between ease of operation and productivity
2Productivity
If spiral cutting flute with increasing pitch is used, then machining overlap is mitigated and cutting speed is increased, but cutting output increases and drill bit wear accelerates
Solution Approach 1:
The patent applies different pitch characteristics to different sections of the spiral flute. The pitch gradually increases from the drill tip to the shank, creating local variations in cutting output. This allows high cutting speed at the tip while reducing wear on upper sections, resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent creates a dynamic cutting process through the varying pitch spiral geometry. The changing pitch along the flute length allows the drill to adapt cutting conditions at different depths, optimizing both cutting speed and wear resistance throughout the drilling operation
3Productivity
If pitch of stepped groove decreases from tip to shank, then cutting speed is increased and drill bit wear is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent systematically varies the pitch parameter of the stepped groove from the drill tip to the shank. This controlled parameter change optimizes cutting speed while managing wear, and the gradual variation keeps manufacturing complexity manageable through a systematic design approach
Data Source
Figure 1~2
Figure 3
AI summary
A twist drill with a multi-step drill point includes a shank (1) and a cutting portion (2). The cutting portion is provided with a spiral flute (3) and a body clearance (4). A tip of the cutting portion is provided with a chisel edge (6) and a cutting edge (5). A flank face (7) connected with the cutting edge is provided with a stepped groove (8) 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.