Tool Holder Shank Segmentation for Deep Internal Machining
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Solution Overview
Problem
Existing tool holders are not suitable for precise internal machining of workpieces with narrow dimensions and deep inner surfaces due to limited rigidity, leading to reduced machining accuracy.
Innovation Solution
A tool holder with an adjustable support that can be placed inside the workpiece, allowing precise positioning and force control of the tool, independent of the shank's rigidity, and featuring a rotatable tool mount and a mechanically relieved shank design for improved rigidity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional tool holder with fixed shank rigidity is used, then the structure is simple, but machining accuracy deteriorates on deep internal surfaces due to limited rigidity
Solution Approach 1:
The tool holder is segmented into a shank portion and a tool carrying portion connected by a resilient connection. This allows the tool carrying portion to deflect independently, maintaining contact force on deep internal surfaces while keeping the shank simple and rigid for accurate positioning.
Solution Approach 2:
The resilient connection between the shank and tool carrying portion allows dynamic adjustment of rigidity parameters. The connection can deflect to accommodate variations in internal surface geometry and maintain optimal contact force, improving machining accuracy on deep surfaces without requiring a completely complex structure.
2Manufacturing precision
If the tool holder shank is made more rigid to improve deep surface machining, then machining accuracy improves, but the tool holder cannot access narrow internal cross-sections
Solution Approach 1:
By separating the shank from the tool carrying portion through a resilient connection, the tool carrier can be made slender and flexible to access narrow passages, while the shank remains rigid for accurate positioning. The resilient connection acts as a flexible joint that allows the tool carrier to navigate tight spaces.
Solution Approach 2:
The resilient connection introduces dynamic flexibility to the tool holder system. The tool carrying portion can dynamically adjust its position and orientation to access narrow internal cross-sections, while the rigid shank maintains overall positioning accuracy for deep surface machining.
3Manufacturing precision
If the tool is pressed against the workpiece with high force to improve machining quality, then surface finish improves, but the tool holder shank experiences excessive mechanical stress
Solution Approach 1:
The resilient connection segments the load path, allowing the tool carrying portion to apply high contact force to the workpiece for improved surface finish, while the shank experiences reduced mechanical stress. The resilient connection absorbs and distributes the forces independently.
Solution Approach 2:
The resilient connection acts as a cushioning element between the shank and tool carrying portion. It beforehand absorbs and dampens mechanical stresses and vibrations generated during high-force machining operations, protecting the shank from excessive stress while maintaining high contact force at the tool-workpiece interface.
4Manufacturing precision
If axial tolerances of the machine tool are reduced to improve positioning accuracy, then machining precision improves, but the cost and complexity of the machine tool increases
Solution Approach 1:
The resilient connection changes the system from requiring high positional rigidity to allowing controlled deflection. This compensates for axial tolerances in the machine tool, maintaining machining precision without requiring excessively tight machine tool specifications or increased complexity.
Data Source
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AI summary
A tool holder (1, 22, 24) for internal machining, in particular internal honing, of a workpiece (2) is described, comprising a tool (6) having a geometrically undefined cutting edge, a spindle (7), a tool holder (5) connected to the spindle (7) for moving the mounted tool (6), and a device (9) for pressing the tool (6) against the workpiece (2) in the feed direction (10). To enable, among other things, the fine machining of non-circular internal surfaces, it is proposed that the device (9) include a support (11) that can be adjusted to the inside (8) of the workpiece (2) and that the distance between the support and the tool (6) is adjustable on the tool holder (1, 22, 24). The tool (6) is rotatably mounted on the tool holder (1, 22, 24) via the tool holder (5).