Indexable Drilling Insert Geometry for Better Chip Evacuation
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Solution Overview
Problem
Existing drilling tools face challenges in effective chip evacuation, particularly when using indexable cutting inserts, which can lead to reduced efficiency and tool wear due to inadequate design for chip removal and indexability.
Innovation Solution
A cutting insert with a pointed shape and acute wedge angles at both cutting edges, allowing for neutral or slight negative axial inclination, promoting chip evacuation and enabling indexability in the insert seat, along with features like protrusions and grooves for enhanced cutting performance and rotation symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a drilling tool uses indexable cutting inserts with conventional geometry, then the tool structure is simplified and insert replacement is easier, but chip evacuation becomes inadequate leading to reduced efficiency and increased tool wear
Solution Approach 1:
The patent applies parameter changes by modifying the wedge angle parameter to be acute (less than 90 degrees) instead of conventional right angles. This parameter change in the insert geometry fundamentally alters chip flow characteristics and enables effective chip evacuation while maintaining indexability, directly resolving the contradiction between ease of manufacture and productivity
2Ease of manufacture
If the cutting insert has a 90 degree angle between the nominal plane and relief face, then the insert geometry is conventional and easy to manufacture, but the length-diameter ratio is limited and chip evacuation is hindered
Solution Approach 1:
The patent changes the geometric parameter from a conventional 90-degree angle to an acute wedge angle. This parameter modification allows the insert to achieve a longer length-diameter ratio while maintaining manufacturability, as the acute angle geometry is still straightforward to produce but enables superior chip evacuation and longer tool life
3Productivity
If the cutting insert uses positive cutting geometry with acute wedge angles, then chip evacuation is promoted and cutting forces are reduced, but the insert design becomes more complex
Solution Approach 1:
The patent employs asymmetry by designing the insert with a specific acute wedge angle configuration that is not symmetric in the conventional sense. The asymmetric geometry optimizes chip flow paths and cutting forces, achieving superior chip evacuation while the design remains relatively simple to manufacture, thus resolving the contradiction between productivity and device complexity
Data Source
AI summary
A cutting insert for a drilling tool is disclosed includes an insert body having a longitudinal direction. A first axial side extends across the longitudinal direction on opposite sides of the insert body. The insert body has a first cutting edge extending along a rim portion at an intersection between a first rake face and the first axial side. The first axial side includes a first relief face and a second relief face. The first and second relief faces form obtuse angles with an imaginary centre plane of the insert body.