Cutting Insert Abutment Geometry for Retention Stability
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Solution Overview
Problem
Cutting tools experience abrasive wear due to chip engagement with jaws, leading to reduced retention of cutting inserts and increased maintenance, particularly in shaving tools made of HSS or cemented carbide, which are costly and require re-grinding.
Innovation Solution
A cutting tool design featuring a cutting insert with specific abutment surfaces and a retaining screw system that provides improved stability and ease of replacement, allowing for high position repeatability without the need for re-alignment or re-grinding, by using a through bore and threaded pocket configuration that ensures accurate seating and secure retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cutting insert is retained in an insert pocket between two generally opposing jaws, then the cutting insert can be held securely during cutting operations, but chip flow along the rake surface causes abrasive wear on the jaw adjacent to the rake surface, reducing retention ability over time
Solution Approach 1:
The patent extracts the harmful interaction between chips and the jaw by introducing a chip breaker element that intercepts and redirects chips away from the rake surface and jaw interface. This prevents chips from flowing along the rake surface and causing abrasive wear on the retention jaw, thereby preserving the jaw's retention ability over time.
Solution Approach 2:
The chip breaker serves as an intermediary element between the cutting insert and the jaw. It mediates the chip flow path, preventing direct contact between chips and the jaw surface, thus protecting the jaw from abrasive wear while maintaining secure insert retention.
2Duration of action of stationary object
If HSS or cemented carbide blocks are used for shaving tools, then tool life and hardness are improved, but maintenance and re-grinding requirements increase
Solution Approach 1:
The cutting tool is segmented into a reusable holder body and replaceable cutting inserts. This allows the expensive HSS or cemented carbide material to be concentrated only in the small insert portion that actually contacts the workpiece, while the majority of the tool (holder) can be reused indefinitely without re-grinding. When the insert becomes worn, only the small insert needs replacement rather than the entire tool.
Solution Approach 2:
The patent employs disposable or replaceable cutting inserts that can be quickly changed when worn. These inserts contain the expensive HSS or cemented carbide material and are designed for limited life, after which they are replaced rather than re-ground. This is more economical than re-grinding entire HSS or carbide blocks.
3Strength
If a cemented carbide flat plate is retained by a clamping arm, then tool hardness is improved, but alignment time and re-alignment after wear increase
Solution Approach 1:
The cutting insert is designed with specific local geometric features including angled surfaces (such as a 45-degree angled surface) and complementary mating surfaces that automatically align the insert with the holder pocket. These localized geometric qualities ensure precise positioning without requiring time-consuming manual alignment procedures.
Solution Approach 2:
The insert and holder pocket are pre-designed with complementary geometric features that automatically establish correct alignment when the insert is installed. The angled surfaces and mating features perform the alignment action automatically during insertion, eliminating the need for separate manual alignment steps before installation.
Data Source
Figure 1~2
Figure 3
Figure 3A~4A
AI summary
A cutting tool (10) has a cutting insert (14) retained within an insert pocket (16) of an insert holder(12) by a retaining screw(18). Spaced apart first insert rear abutment surfaces (42) abut 'spaced apart first pocket rear abutment surfaces (78), a second insert rear abutment surface (45) abuts a second pocket rear abutment surface (82), and' spaced apart insert lower abutment surfaces (56) abut spaced apart pocket lower abutment surfaces (88). The cutting insert (14) has a first dimension (Dl) taken between extremities of the insert side surfaces (28), a second dimension (D2) taken between extremities of the insert upper(30) and lower (32) surfaces, and, a fourth dimension (D4) taken between the insert lower abutment surfaces (56) and the insert upper surface (30). The size ratio between the fourth dimension (D4) and the second dimension (D2) is in the range of 0.2 to 1, and, preferably, in the range of 0.55 to 0.6. The size ratio between the first dimension (Dl) and the second dimension (D2) is in the range of 1 to 2.