Self-Drilling Screw Structure for Stable Chip Discharge
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Solution Overview
Problem
Conventional self-drilling screws have poor chip discharge capability and stability during hole-expanding due to directly stamped and molded chip discharge grooves, leading to displacement and drilling position deviations.
Innovation Solution
A self-drilling screw structure with discontinuous cutting edges formed through stamping and thread rolling processes, featuring a concave neck portion connected to both sets of cutting edges, enabling effective chip discharge and improved stability during hole-expanding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chip discharge grooves are directly stamped and molded on a flat surface, then mass production is enabled, but chip discharge capability is poor and drilling position deviation occurs
Solution Approach 1:
The cutting edge is segmented into two distinct parts: drill bit cutting edges formed by stamping and drill tail cutting edges formed by thread rolling. This segmentation allows each part to be optimized for its specific function while maintaining mass production capabilities through standardized manufacturing processes.
Solution Approach 2:
The patent merges two different manufacturing processes (stamping and thread rolling) to form a unified cutting edge structure. The drill bit cutting edges from stamping and drill tail cutting edges from thread rolling work together as an integrated system, combining the advantages of both processes.
2Ease of manufacture
If chip discharge grooves are stamped and molded on a flat surface, then manufacturing simplicity is maintained, but chip discharge efficiency is poor causing shaking and instability
Solution Approach 1:
The concave neck portion introduces a curved, three-dimensional structure to connect the drill bit and drill tail sections. This curvature creates a natural chip discharge pathway that improves chip flow efficiency while maintaining manufacturing simplicity through stamping and thread rolling processes.
Solution Approach 2:
Different sections of the screw are given different local qualities: the drill bit section has cutting edges optimized for initial hole formation, the concave neck provides chip discharge pathways, and the drill tail section has cutting edges optimized for hole expansion. Each local region is optimized for its specific function.
3Ease of manufacture
If conventional stamped self-drilling screws are used, then cost-effectiveness is maintained, but chip accumulation occurs resulting in shaking and reduced stability
Solution Approach 1:
The concave neck portion acts as an intermediary element between the drill bit cutting edges and drill tail cutting edges. It provides a dedicated chip discharge pathway that prevents chip accumulation, thereby improving drilling stability while maintaining cost-effectiveness through standardized manufacturing processes.
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
The invention provides a self-drilling screw structure and a manufacturing method thereof, wherein the manufacturing method includes: providing screw body, forming drill tail screw rod section, forming concave neck portion, forming drill tail cutting edge and forming thread. The self-drilling screw structure including a screw head portion (11) and a screw rod portion (12), the screw rod portion (12) is sequentially provided with a threaded screw rod section (121), a drill tail screw rod section (122) and a drill bit screw rod section (123), the drill tail screw rod section (122) has a rod diameter of drill tail (D2), a plurality of drill tail cutting edges (1221) and a plurality of drill tail chip discharge grooves (1222), the drill bit screw rod section (123) is provided with a concave neck portion (1231), and the drill bit screw rod section (123) is protruded to form a plurality of drill bit cutting edges (1234) and the plurality of drill bit chip discharge grooves (1235).