Cutting Tool Offset Threaded Projection Abutment
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Solution Overview
Problem
Existing cutting tool insert mounting arrangements face challenges with insert size variations leading to poor workpiece quality and complex, costly repairs due to the difficulty in achieving precise three-point contact and the limitations of current bottom locking and side abutment surface designs.
Innovation Solution
A toolholder with a projection having an internally threaded opening offset from its central axis and radial abutment members closer to the projection's central axis, combined with a cutting insert featuring recesses for the abutment members, minimizes the distance between the insert's cutting edge and abutment surfaces for accurate mounting and stability, allowing for easy replacement of damaged components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If three-point contact mounting is used between insert and toolholder, then insert stability is improved, but manufacturing precision deteriorates due to difficulty in achieving precise contact points
Solution Approach 1:
A spherical abutment member is introduced as an intermediary element between the toolholder and cutting insert. The sphere contacts the insert at a single point on its top surface and is supported by the toolholder, automatically achieving precise three-point contact geometry without requiring high-precision machining of the toolholder pocket. The spherical shape self-adjusts to provide the necessary contact points.
2Device complexity
If insert size variations are not compensated, then manufacturing complexity is reduced, but workpiece quality deteriorates due to cutting edge position variations
Solution Approach 1:
The mounting system changes the reference parameter from the insert's bottom surface to its top surface. The spherical abutment member contacts the insert at the top surface, which is closer to the cutting edge. This parameter change means that size variations in the insert body have less leverage on cutting edge position, automatically compensating for manufacturing tolerances without adding complexity.
3Manufacturing precision
If bottom locking arrangement with projection is used, then insert size variation impact is reduced, but insert support quality deteriorates due to poor support during cutting operations
Solution Approach 1:
The support point is moved from the bottom surface of the insert to the top surface by using a spherical abutment member that contacts the insert from above. This dimensional change allows the support force to be applied more favorably during cutting operations, improving insert support strength while maintaining the precision benefits of bottom locking.
4Ease of repair
If replaceable abutment members are used, then ease of repair is improved, but device complexity increases due to additional components
Solution Approach 1:
The abutment function is segmented into a separate replaceable spherical member rather than being integrated into the toolholder. This allows the abutment sphere to be independently replaced if damaged, significantly improving ease of repair. The segmentation adds only one simple component and one replacement operation.
Data Source
AI summary
A toolholder includes a bottom abutment surface, a projection extending upwardly from the bottom abutment surface, the projection including an internally threaded opening, having a central axis that is offset from a central axis of the projection in a first direction, and a clamping screw having external threads for mating with threads of the internally threaded opening and a head having a bottom clamping surface shaped as a truncated cone for contacting an insert clamping surface and urging an insert substantially in a first direction when the clamping screw is tightened relative to the toolholder and the insert. The toolholder also includes at least one abutment member extending from a side wall of the projection in a radial direction, each abutment member having an abutment point, at least which is closer to the central axis of the projection than to the central axis of the internally threaded opening.