Self-Tapping Screw Drill Bit Structure for Chipbreaking and Faster Drilling
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Solution Overview
Problem
Conventional self-tapping screws experience poor cutting efficiency and increased drilling time due to elongated chip formation that blocks the screw tip, leading to reduced drilling speed and potential damage.
Innovation Solution
The drill bit structure features two first cutting edges adjacent to third cutting edges, which extend concavely and are reinforced by a chipbreaker, along with arcuate grooves to break and remove chips, enhancing drilling capacity and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the conventional self-tapping screw uses protruded faces on the outer rims of cut faces, then the cutting edges are enhanced, but the conical tip abuts and drills into the workpiece causing poor cutting effect and slow screwing speed
Solution Approach 1:
The drill bit is segmented into distinct functional zones: a conical tip for initial penetration, first cutting edges for material removal, and second cutting edges for threading. This segmentation allows each zone to perform its specific function optimally without interference, resolving the contradiction between cutting sharpness and screwing speed.
Solution Approach 2:
The invention extends the first cutting edges along the central axis to heights not less than the conical face height, adding a vertical dimension to the cutting edges. This dimensional extension ensures that the first cutting edges engage the workpiece before the conical tip fully penetrates, preventing the poor cutting effect caused by tip abutment while maintaining cutting sharpness.
2Ease of operation
If the screw tip is drilled into the workpiece, then the conical tip penetrates the material, but chips elongate and twist around the screw tip blocking the threaded section
Solution Approach 1:
Arcuate grooves are extracted and defined on the peripheral side of the drill bit to create dedicated chip removal pathways. These grooves extract chips from the cutting zone and guide them away from the screw tip and threaded section, preventing chip entanglement while maintaining penetration capability.
Solution Approach 2:
The arcuate grooves act as intermediary channels between the cutting zone and the exterior environment. They provide a designated pathway for chip evacuation, mediating the removal of chips before they can twist and block the threaded section, thus resolving the chip entanglement problem.
3Productivity
If the first cutting edges are extended concavely to enhance drilling capacity, then the drilling speed increases, but the device complexity increases
Solution Approach 1:
The first and second cutting edges are merged into a unified continuous structure on the drill bit. The first cutting edges extend from the peripheral side toward the central axis, while the second cutting edges extend from the central axis toward the peripheral side, merging to form a complete cutting system that enhances drilling speed without requiring separate independent components, thus limiting complexity increase.
Data Source
AI summary
A drill bit structure of a self-tapping screw is rotated clockwise to screw with a workpiece or is rotated counterclockwise to remove from the workpiece, and the self-tapping screw contains: a head, a shank, and a drill bit. The head is configured to connect with a tool. The shank integrally extends from the head. A conical face has a tip, two arcuate grooves, and two first cutting edges. Each of the first cutting edges is formed on a connection portion of each arcuate groove and the conical face. The drill bit includes two third cutting edges, and each third cutting edge is adjacent to the tip, shapes of the two first cutting edges correspond to shapes of the two third cutting edges respectively, and heights of the two first cutting edges are not less than the conical face. Each first cutting edge has a reinforcement portion.