Twisted Gash Drill Geometry for Smooth Aluminum Chip Evacuation
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Solution Overview
Problem
Drills used for cutting aluminum alloys often experience poor chip discharge performance due to small and short chips getting caught at the corner portion connecting the R gash and discharge flute, leading to clogging issues.
Innovation Solution
A drill design featuring a gash portion connected to the discharge flute while twisting along the helix angle of the discharge flute, with a length between 0.5 to 1.4 times the drill diameter, and extending in a circular arc shape to connect with the body clearance, ensuring smooth chip discharge without clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a corner portion is formed at the section connecting the R gash and the discharge flute, then the drill structure is simple and easy to manufacture, but the chip discharge performance deteriorates as chips become caught on the corner portion
Solution Approach 1:
The patent applies curvature by forming the gash portion in a circular arc shape and connecting it to the discharge flute with a smooth curved transition rather than a sharp corner. This curved connection eliminates the corner portion that causes chip accumulation, allowing chips to flow smoothly into the discharge flute while maintaining manufacturing simplicity.
2Productivity
If the gash portion is extended to connect with the outer peripheral surface, then the chip discharge performance is improved, but the rigidity of the drill main body decreases
Solution Approach 1:
The patent applies local quality by providing the body clearance and gash portion connection to the outer peripheral surface only at specific locations, while maintaining the overall rigidity of the drill main body. The clearance is localized to where it is most beneficial for chip discharge, rather than uniformly reducing the entire structure's rigidity.
3Object-generated harmful factors
If a body clearance is provided in the outer peripheral surface, then the frictional resistance with work material is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent combines the body clearance formation with the circular arc gash portion, creating a smooth curved transition that reduces friction between the drill and work material. The curved geometry is formed in a single machining operation, avoiding the need for separate complex manufacturing steps.
Data Source
AI summary
A drill includes a drill main body to be rotated around a shaft center, discharge flutes provided in a helical shape in an outer peripheral surface, a cutting edge formed at a ridge section between an inner face, of the discharge flute, and a flank of the drill main body at a leading end portion, a thinning edge provided at the leading end portion of the drill main body, a thinning face being a rake face of the thinning edge, and connecting the thinning edge with the discharge flute, and a gash portion connected to the thinning face, a ridge line between the gash portion and the flank extending in a circular arc shape from an inner end of the thinning edge, and being connected to the discharge flute. The gash portion is connected to the discharge flute while twisting along a helix angle of the discharge flute.