Self-Drilling Screw Tip Structure for Low-Resistance Chip Evacuation
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Solution Overview
Problem
Conventional screws face challenges in efficiently cutting through workpieces due to limited cutting effectiveness of the groove, leading to increased drilling resistance, chip accumulation, and potential workpiece cracking.
Innovation Solution
The screw design incorporates a drill portion with opposite groove regions and drilling regions, featuring cutting units with inclined cutting edge sections and slanted join walls, allowing for efficient cutting and chip removal while reducing drilling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional groove is used on the shank, then the screw can accommodate chips, but the cutting effect is limited and chips accumulate blocking the groove
Solution Approach 1:
The single groove is segmented into multiple grooves (first groove and second groove) positioned at different locations and orientations. This segmentation allows chips to be distributed and evacuated through multiple pathways rather than accumulating in a single channel, significantly improving chip removal efficiency while maintaining effective cutting action.
Solution Approach 2:
The grooves are positioned not only along the longitudinal direction but also in different transverse positions and orientations around the shank. This multi-dimensional arrangement creates three-dimensional chip evacuation pathways, preventing chip accumulation by utilizing spatial distribution rather than relying on a single linear groove.
2Object-generated harmful factors
If the groove area is increased to receive more chips, then chip capacity improves, but drilling resistance increases
Solution Approach 1:
Instead of creating one large groove that increases drilling resistance, the chip accommodation function is segmented into multiple smaller grooves. These distributed grooves provide sufficient total capacity for chip storage while maintaining smaller individual cross-sections that create less resistance during the drilling operation.
Solution Approach 2:
The grooves are strategically positioned at specific locations around the shank where they can effectively receive and evacuate chips without interfering with the primary cutting action. This local placement optimizes the balance between chip accommodation and drilling resistance by providing chip management capability exactly where needed rather than uniformly increasing groove area.
3Productivity
If the groove is made deeper to cut fibers more effectively, then cutting performance improves, but the groove becomes blocked more easily
Solution Approach 1:
The cutting and chip evacuation functions are segmented between multiple grooves at different depths and positions. Each groove can be optimized for its specific function without being compromised by the need to perform both deep cutting and extensive chip storage, preventing blockage by distributing the workload across multiple pathways.
Solution Approach 2:
Chip evacuation is achieved not only through longitudinal depth but also through transverse positioning and orientation of multiple grooves. This multi-dimensional chip evacuation strategy allows fibers to be cut effectively while chips are directed out through various spatial pathways, reducing the likelihood of any single groove becoming blocked.
Data Source
AI summary
A screw includes a head, a shank, a thread unit, and a drill portion. The drill portion includes a drill body with an end portion and opposite groove regions and opposite drilling regions respectively formed on the drill body. Regarding each drilling region, on one side of each groove region is formed a cutting unit which has a connecting section extending outwards from the groove region and a cutting edge section connected to the connecting section, and on the other side of the groove region is mainly formed a first join wall which has a slanted surface so that the drill body narrows gradually towards the end portion. A first distance defined between two junctions where respective connecting sections meet respective cutting edge sections is greater than an outer diameter of the shank. Accordingly, the screw reams, cuts quickly, removes chips, and attains a stable fastening effect.