Step-Cutting Twist Drill for Accurate Positioning and Lower Reaction Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional twist drills are difficult to position and operate efficiently, requiring significant arm strength and power, leading to low drilling speed and efficiency, and are prone to damage due to high reaction forces and burr generation.
Innovation Solution
A twist drill design featuring a shank portion with a cone and cylinder portion, equipped with a spiral flute for chip evacuation and composite cutting blade groups that increase in diameter, providing a top blade for positioning and dispersing cutting forces across multiple blades, reducing reaction forces and burr formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two symmetrically distributed linear cutting edges are used to complete metal cutting, then the cutting function is achieved, but relatively large power is required and reaction forces damage the cutting edges
Solution Approach 1:
The single linear cutting edge is segmented into multiple composite cutting blade groups with step surfaces, creating multiple cutting edges that work simultaneously. This segmentation distributes the cutting load across multiple edges, reducing the power required per edge while maintaining overall productivity.
Solution Approach 2:
Different step surfaces (first step surface and second step surface) create cutting edges with different local properties. The major cutting edge and minor cutting edge have different flank surfaces and back portions, allowing optimized local quality for different cutting zones, reducing overall power consumption.
2Reliability
If two symmetrically distributed linear cutting edges are used, then cutting is achieved, but relatively large reaction forces are applied onto cutting edges causing damage
Solution Approach 1:
The cutting function is segmented into multiple composite cutting blade groups, distributing the reaction force across multiple cutting edges. Each group handles a portion of the total reaction force, preventing any single edge from being overloaded and damaged.
Solution Approach 2:
The first and second step surfaces provide different local quality characteristics for the major and minor cutting edges. This allows each cutting edge to have optimized properties for its specific function, improving durability under reaction forces.
3Measurement precision
If conventional twist drill structure is used, then drilling function is achieved, but positioning of drill hole is difficult
Solution Approach 1:
The top blade at the tip performs preliminary positioning action before the composite cutting blade groups engage in cutting. This preliminary action establishes accurate drill hole position, making positioning easier and more precise.
Solution Approach 2:
The top blade has distinct local quality different from the composite cutting blade groups, optimized specifically for positioning function. This specialized local quality improves positioning accuracy without compromising cutting performance.
4Speed
If conventional twist drill with two cutting edges is used, then cutting is achieved, but drilling speed is low
Solution Approach 1:
The cutting function is segmented into multiple composite cutting blade groups that can operate simultaneously at different radial positions. This increases the effective cutting width and drilling speed while maintaining high productivity through distributed cutting action.
Solution Approach 2:
The cutting action transitions from a single linear edge to multiple step surfaces arranged in three-dimensional space. The first and second step surfaces create cutting edges at different heights and radial positions, utilizing another dimension to increase cutting efficiency and speed.
Data Source
AI summary
The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.