Indexable Drill Flute Geometry for Spiral Chip Control
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Solution Overview
Problem
Existing metal cutting indexable drill tools face challenges in effectively controlling and evacuating chips, particularly spiral cone chips formed by center inserts, which can lead to entanglement and surface damage due to chip length issues, and existing drill flutes do not adequately address the problem of too long chips.
Innovation Solution
A metal cutting indexable drill tool with a drill flute design featuring a chip forming surface perpendicular to the insert seat, positioned at a specific distance from the peripheral corner of the center insert, forming a curve with an imaginary inscribed sphere, and optimized chip parameter ratios to control chip diameter and evacuation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drill flutes are provided for improved chip evacuation and control, then chip evacuation is improved, but the problem of too long chips is not addressed
Solution Approach 1:
The patent applies parameter changes by precisely defining the position of the chip forming surface using the chip parameter A (distance X divided by drill diameter Dc, where 0.3 ≤ A ≤ 0.5). This parameter control ensures chips are formed to optimal lengths - not too short to evacuate properly, not too long to entangle - thereby resolving the contradiction between chip evacuation and chip length control
Solution Approach 2:
The patent replaces conventional drill flute geometry with a mathematically defined chip forming surface position based on the intersection curve with an inscribed sphere. This substitution of geometric design approach enables precise control over chip diameter and length, transforming chip formation from a geometric approximation to a controlled mathematical relationship
2Reliability
If the chip becomes too long, then chip evacuation is maintained, but the chip may entangle the drill tool and result in poor process security and surface damages
Solution Approach 1:
By controlling the chip parameter A within the range 0.3 ≤ A ≤ 0.5, the patent ensures chips achieve sufficient length for proper evacuation while preventing excessive length that would cause entanglement. The upper bound of A=0.5 specifically prevents chip diameter from becoming too large, eliminating the root cause of entanglement while maintaining evacuation capability
3Object-affected harmful factors
If the chip becomes too short, then chip entanglement is prevented, but problems with chip evacuation from the drill tool occur
Solution Approach 1:
The lower bound of the chip parameter A (A ≥ 0.3) ensures chips are formed with sufficient length and diameter to evacuate properly from the drill flutes. This parameter setting prevents chips from being too short, which would cause evacuation problems, while the upper bound maintains control over chip dimensions
Data Source
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AI summary
A metal cutting indexable drill tool (100), comprising: an elongated drill body (101) having a boring shaft (102) and a mount shank (103); a center drill insert (104) mounted at a distal end (105) of the boring shaft (102) in an insert seat (106) configured to hold the insert against a bottom of the insert seat (106); a drill flute (107) of the boring shaft (102) configured to direct and form a chip from the center drill insert (104), wherein the drill flute (107) comprises a chip forming surface (108) at a distal end (109) of the drill flute (107); characterized in that the chip forming surface (108) is perpendicular to the bottom of the insert seat (106) for the center drill insert (104); and in that the chip forming surface (108) is arranged at a distance X from a peripheral corner (110) of the center drill insert (104) to a point (301) on a curve (302), which curve is formed by the intersection of the chip forming surface (108) and an imaginary inscribed sphere (302), wherein the center (303) of the imaginary inscribed sphere coincide with the center of the distal end (105) of the boring shaft (102), wherein the radius of the imaginary inscribed sphere is defined by the peripheral corner (110) of the insert (104); and wherein the distance X divided with the diameter of the drill tool Dc is equal to a chip parameter A which is indicative of the chip diameter to boring diameter ratio; wherein the chip parameter A is 0.3 ≤ A ≤ 0.5.