Cutting Insert Geometry for Hole-Making Without Pre-Drilling
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Solution Overview
Problem
Existing cutting inserts require a pre-formed hole in workpieces for boring and drilling, increasing the number of machining processes.
Innovation Solution
A cutting insert and tool design that allows for boring and drilling without a pre-formed hole, featuring a plate-like cutting insert with positive clearance angles and a cylindrical cutting tool body, enabling machining without rotating the workpiece by using the cutting insert's upper and lower cutting edges to create a machined hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a prepared hole is formed in advance in a workpiece for boring or drilling, then the machining process can be completed, but the number of machining processes increases
Solution Approach 1:
The patent combines the hole formation process and the boring/drilling process into a single integrated operation. The cutting insert is designed with specific geometry (positive clearance angles on both first and second flanks, and a rounded nose portion) that allows it to both create the hole and perform the finishing operation simultaneously, eliminating the need for a separate hole preparation step.
Solution Approach 2:
The cutting insert is designed to perform multiple functions: it can create the initial hole (drilling function) and simultaneously perform the boring/finishing operation. This multi-functional design allows a single tool to replace what would traditionally require multiple specialized tools or sequential operations, thereby reducing the total number of machining processes.
2Productivity
If a cutting insert with positive clearance angles is used for boring and drilling, then the number of processes can be reduced, but the cutting insert structure becomes more complex
Solution Approach 1:
The cutting insert applies the positive clearance angle feature specifically to the flank surfaces that contact the workpiece during cutting. This localized application of the clearance angle geometry ensures that the complex structural feature is only present where needed for cutting performance, rather than throughout the entire insert structure, thereby minimizing overall complexity while achieving the desired functionality.
Solution Approach 2:
The cutting insert employs asymmetric geometry with positive clearance angles on the flanks and a rounded nose portion, deviating from traditional symmetric or simpler insert designs. This asymmetric configuration is optimized for the dual function of hole creation and boring, allowing the insert to navigate and cut effectively in scenarios where conventional symmetric inserts would fail, thus enabling process consolidation despite increased structural complexity.
Data Source
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AI summary
There is provided a cutting insert capable of boring or drilling without the formation of a prepared hole in a workpiece. A cutting edge includes a cutting edge portion extending from the outer peripheral side to the center axis side of a cutting tool body when the cutting insert is attached to a mounting seat , reaching a first plane including the center axis, and traversing from one side to the other side of a second plane which is perpendicular to the first plane and which includes the center axis.