Stepped Drill Insert Structure for Cooler Chip Transition Zones
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Solution Overview
Problem
Metal cutting inserts with stepped edges experience increased temperature in the transitional region, leading to reduced lifetime and surface finish issues during metal drilling due to chip compression.
Innovation Solution
Incorporating a step in the side view of the metal cutting insert, with a specific ratio of step distances in top and side views to reduce chip compression and temperature, and featuring a corner edge for continuous chip formation and efficient chip evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stepped cutting edge with transitional region is used to cut continuous chips, then chip control and evacuation are improved, but temperature increases in the transitional region reducing insert lifetime
Solution Approach 1:
The invention adds a third dimension to the stepped cutting edge geometry by defining step heights in both radial direction (h1) and axial direction (h2). This creates a three-dimensional stepped structure that redirects chip flow to reduce compression in the transitional region, thereby lowering temperature while maintaining effective chip evacuation.
Solution Approach 2:
The invention optimizes the geometric parameters of the stepped cutting edge by establishing specific ratio relationships between h1 and h2 (0.8 ≤ h1/h2 ≤ 1.2). This parameter optimization ensures that the chip compression is minimized in the transitional region, reducing temperature increase while maintaining continuous chip formation and evacuation capabilities.
2Stability of the object's composition
If chip compression occurs in the transitional region, then continuous chips are formed, but temperature increases reducing insert lifetime
Solution Approach 1:
By introducing axial step height (h2) in addition to radial step height (h1), the invention creates a three-dimensional chip path that reduces compression forces in the transitional region. This dimensional addition allows continuous chip formation while minimizing temperature increase that would otherwise reduce insert lifetime.
Solution Approach 2:
The invention optimizes the ratio between radial step height (h1) and axial step height (h2) within specific ranges (0.8 ≤ h1/h2 ≤ 1.2) to achieve the right balance between chip continuity and compression reduction. This parameter optimization ensures continuous chips are formed without excessive compression-induced temperature rise.
3Productivity
If increased temperature occurs in the transitional region, then chip evacuation is maintained, but surface finish deteriorates
Solution Approach 1:
By optimizing the ratio between radial step height (h1) and axial step height (h2) within specific ranges, the invention reduces temperature increase in the transitional region. This temperature control prevents thermal damage to the workpiece surface, improving surface finish while maintaining effective chip evacuation through the stepped geometry.
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 solution effectively decreases temperature in the transitional region, enhancing the lifespan of the insert and improving surface finish by minimizing chip compression forces.
Implementation Method 1
the increased temperature in the transitional region of the stepped edge is caused by compression of the chip in the transitional region
Data Source
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AI summary
A metal cutting drill insert 100,400 for a drill tool comprising: opposing top surface 101,401 and bottom surface 102,402 with a symmetry axis of the cutting drill insert extending there between, and a peripheral side surface 103,403 extends between said top surface and said bottom surface, wherein the top surface 101,401 comprises a rake face 104,404 and the side surface 103,403 comprises a clearance face 105,405. The metal cutting drill insert further comprises at least one stepped cutting edge 106,406 configured to cut a continuous chip along said at least one stepped cutting edge, wherein said at least one stepped cutting edge is formed at an intersection of a rake face 104,404 of the top surface 101,401 and an adjoining clearance face 105,405 of the side surface 103,403, wherein in a top view facing the top surface of the metal cutting insert, said at least one stepped cutting edge comprises a step formed by a transitional edge 107,507 between a first part edge 108,508 and a second part edge 109,509; characterized in that in a top view facing the top surface 101,401 of the metal cutting insert 100,400, said step extends in a radial direction relative the symmetry axis, a first distance h1; and in a side view facing the peripheral side surface 103,503 of the metal cutting insert 100,400, said step extends in a direction from the bottom surface towards the top surface, a second distance h2, wherein 0.8·h1 ≤ h2 ≤ 1.2·h1.