Twist Drill Tapering Core and DLC Coating for Aluminum Jamming
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Solution Overview
Problem
Conventional twist drills experience reduced useful life and often become jammed when machining wrought aluminum alloys, especially in automobile body part manufacturing where lubricants cannot be used due to cleanliness requirements.
Innovation Solution
A twist drill design with a drill shaft and cutting part featuring spiral chip flutes, a core thickness of (15±3)% of the drill diameter at the tip, tapering towards the shaft, primary and secondary clearance angles of (19±3)° and (26±4)° respectively, and a diamond-like carbon coating, along with internal cooling borings and precision-ground surfaces, to enhance cutting efficiency and prevent jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional twist drills are used for machining wrought aluminum alloys, then the drilling operation can be performed, but the tool useful life is significantly restricted and the drill becomes jammed or stuck
Solution Approach 1:
The patent applies parameter changes by optimizing the core thickness to (15±3)% of the drill diameter and setting specific clearance angles (primary: 19±3°, secondary: 26±4°). These parameter modifications prevent chip jamming in the flutes while maintaining structural integrity, thereby extending tool useful life and improving reliability when machining wrought aluminum alloys
Solution Approach 2:
The patent implements local quality by applying a diamond-like carbon coating specifically to the cutting part and chip flutes where chip removal occurs. This localized coating provides enhanced non-stick properties and wear resistance precisely where chips are generated and evacuated, preventing jamming without requiring coating the entire drill
2Duration of action of moving object
If oils or lubricants are used to extend tool useful life, then cutting performance may improve, but the workpiece surface becomes contaminated requiring additional cleaning processes
Solution Approach 1:
The patent applies self-service by using the diamond-like carbon coating on the chip flutes to create a non-stick surface that naturally prevents chip adhesion and facilitates chip evacuation without requiring external lubricants. The coated surface serves its own lubrication function, eliminating the need for oils that would contaminate the workpiece
Solution Approach 2:
The diamond-like carbon coating acts as an intermediary between the metal chip and the drill flute surface. This intermediate layer prevents direct contact and adhesion between the aluminum alloy chips and the drill, enabling smooth chip removal without lubricants that would contaminate the automobile body part surface
3Productivity
If the core thickness is reduced to improve chip evacuation, then drilling performance improves, but the structural strength of the drill may be compromised
Solution Approach 1:
The patent resolves this contradiction by precisely setting the core thickness parameter to (15±3)% of the drill diameter. This optimized parameter provides sufficient flute space for chip evacuation while maintaining adequate core thickness for structural strength, allowing high productivity without compromising drill integrity
Solution Approach 2:
The patent applies local quality by reinforcing the drill structure through specific geometry design - the core thickness tapers from the drill tip toward the shaft, providing maximum strength where needed while maintaining optimal chip evacuation space at the cutting end where chips are generated
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design allows for extended tool life and reduced wear, enabling series processing of wrought aluminum alloys without jamming, with a significant increase in cutting value and reduced machining time.
Implementation Method 1
a diamond-like carbon coating, along with internal cooling borings and precision-ground surfaces
Implementation Method 2
internal cooling borings and precision-ground surfaces
Implementation Method 3
spiral chip flutes along the cutting part that form a drill core
Data Source
AI summary
Twist drill with a drill shaft and a cutting part that extends to a drill tip, with spiral chip flutes along the cutting part that form a drill core, wherein the drill diameter and/or core thickness diminish or taper from the drill tip toward the shaft. The abstract of the disclosure is submitted herewith as required by 37 C.F.R. §1.72(b). As stated in 37 C.F.R. §1.72(b): A brief abstract of the technical disclosure in the specification must commence on a separate sheet, preferably following the claims, under the heading “Abstract of the Disclosure.” The purpose of the abstract is to enable the Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract shall not be used for interpreting the scope of the claims. Therefore, any statements made relating to the abstract are not intended to limit the claims in any manner and should not be interpreted as limiting the claims in any manner.