Cutting Insert Contact Surface Layout for Precise Tool Holder Positioning
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Solution Overview
Problem
Conventional cutting tools with knurled interfaces for small precision mechanical parts, such as those in the watchmaking industry, face challenges in stability and precision due to high load on screws and raw sintered structures, leading to reduced positioning accuracy.
Innovation Solution
A cutting insert with an elongate shape and laterally protruding elevation featuring multiple contact surfaces, including lateral, axial, and horizontal holder contact surfaces, which provide stable and precise contact with the tool holder, reducing the need for extensive grinding and allowing for a compact design with enhanced mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a grooved interface structure is used between cutting insert and tool holder, then the cutting insert can be attached to the tool holder, but the forces in axial direction are transferred via screws leading to high load on screws and reduced positioning accuracy
Solution Approach 1:
The interface is segmented into multiple flat contact surfaces (lateral, axial, and horizontal surfaces) distributed across the cutting insert body, rather than relying on a single grooved structure. This segmentation distributes the load paths and eliminates dependency on screws for force transfer, thereby improving positioning accuracy while maintaining attachment capability.
Solution Approach 2:
The screw fastening mechanism is extracted from the force transfer path. Instead of using screws to transfer axial forces, the invention uses direct contact between flat surfaces of the cutting insert and corresponding surfaces of the tool holder, removing the screws from the load-bearing function and eliminating their negative impact on positioning accuracy.
2Ease of manufacture
If a raw sintered grooved structure is used, then the interface can be manufactured, but the positioning accuracy is negatively affected
Solution Approach 1:
The interface surfaces are designed with specific local qualities - flat, precision-ground surfaces at critical contact points (lateral, axial, and horizontal surfaces) - while other parts of the cutting insert can remain as raw sintered structure. This localized precision processing maintains overall manufacturability while significantly improving positioning accuracy at the interface.
3Volume of moving object
If very small tool holder dimensions (6x6 mm or less) are used, then the tool is suitable for miniature parts production, but the interface stability and overall tool stability are compromised
Solution Approach 1:
The interface design utilizes multiple dimensions by providing contact surfaces in lateral, axial, and horizontal directions. This multi-dimensional contact approach maximizes the stable interface within the constrained small volume of the tool holder, achieving adequate stability despite the reduced size by exploiting spatial distribution of contact points.
Data Source
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AI summary
The invention relates to a cutting insert (12) for a tool (10) for machining a workpiece, comprising a cutting edge (22) and a cutting insert bore (32). The cutting insert (12) extends along a cutting insert longitudinal direction (18), and the cutting insert bore (32) extends along a bore axis (36) which runs orthogonally to the cutting insert longitudinal direction (18). The cutting insert (12) has a laterally protruding elevation (30). A lateral holder contact surface (40a), an axial holder contact surface (42), and a horizontal holder contact surface (44a) for bringing the cutting insert (12) into contact with a tool holder (14) are arranged on the elevation (30). The lateral holder contact surface (40a) runs orthogonally to the first bore axis (36), and the axial holder contact surface (42) and the first horizontal holder contact surface (44a) run orthogonally to the lateral holder contact surface (40a) and transversely to each other. The invention further relates to a tool holder (14) with a receiving area (54) for the cutting insert (12), said receiving area (54) being provided with a depression (56) which has contact surfaces (56, 58, 60) that correspond to the contact surfaces of the cutting insert (12), and to a tool (10) composed of the cutting insert (12) and the tool holder (14).