Self-Drilling Screw Chip Flute Connection for Smooth Chip Discharge
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Solution Overview
Problem
Conventional self-drilling screws face issues with chip flute misalignment during manufacturing, leading to incomplete communication between chip flutes, which causes chip buildup and increased wear on the drill tail due to the need for greater rotational force to discharge chips.
Innovation Solution
The self-drilling screw design incorporates two chip flutes at different positions that form a connection at the joint between the drill bit and drill tail sections, with the first chip flute width being less than or equal to half the screw rod diameter and the second chip flute width being greater, ensuring effective communication and chip discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single chip flute is formed on the rod body, then the structure is simple, but the chip flute cannot completely communicate with the chip flute of the drill tail due to alignment problems, causing chip discharge blockage
Solution Approach 1:
The single chip flute is divided into two separate chip flutes: a first chip flute on the drill tail and a second chip flute on the rod body. These two chip flutes are positioned at different locations and connect through the hollow interior of the drill tail, forming a complete chip discharge pathway. This segmentation eliminates alignment issues between overlapping flutes while maintaining effective chip removal.
Solution Approach 2:
The hollow interior of the drill tail acts as an intermediary channel that connects the first chip flute (on the drill tail) with the second chip flute (on the rod body). This intermediate space allows chips to be transported from the drilling location through the drill tail's interior to the rod body's chip flute, ensuring continuous chip discharge without requiring precise alignment of overlapping flutes.
2Productivity
If greater rotational force is applied to drive the drill tail, then chip discharge can be forced, but the drill tail wears down quickly due to increased external force
Solution Approach 1:
The chip discharge function is segmented into two parts: the first chip flute on the drill tail and the second chip flute on the rod body. This segmentation creates a more efficient chip ejection pathway that reduces resistance, allowing chips to be removed with less rotational force. Consequently, the drill tail experiences reduced mechanical stress and wears down more slowly, extending its service life.
3Quantity of substance
If the first chip flute width is made larger, then chip capacity increases, but the connection between chip flutes may be compromised
Solution Approach 1:
The chip flute widths are optimized with different characteristics at different locations. The first chip flute on the drill tail has a width designed to match the chip generation zone, while the second chip flute on the rod body has a width optimized for chip ejection. The connection between them through the drill tail's hollow interior ensures proper alignment and communication without requiring uniform width throughout, allowing each section to be optimized for its specific function.
Data Source
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AI summary
A self-drilling screw structure (100) comprises a screw head (10) and a screw rod (20) extending outwardly from the screw head (10). The screw rod (20) is sequentially formed with a drill bit section (21) at one end opposite to the screw head (10), a drill tail section (22) and a screw thread section (23). The drill bit section (21) comprises two first cutting edges (211) extending helically and intersecting at a chisel edge P, and two first chip flutes (212) located at the positions respectively between the two first cutting edges (211) and extending from the chisel edge toward the drill tail section (22). The drill tail section (22) comprises two second cutting edges (221) extending helically toward the screw thread section (23), and two second chip flutes (222) located at the positions respectively between the two second cutting edges (221) and extending helically toward the screw thread section (23). Each first chip flute (212) and the second chip flute (222) form a connection (24) at a joint between the drill bit sections (21) and drill tail sections (22).