Force-Controlled Self-Sharpening of Machining Tool Cutting Elements
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Solution Overview
Problem
Machining tools require frequent replacement of cutting elements due to wear, leading to increased costs and material waste, as the cutting edge becomes dull and can no longer effectively remove material from workpieces.
Innovation Solution
A force-controlled self-sharpening method for cutting elements, where a sensor or elastic actuator maintains a constant orthogonal force on the cutting edge, allowing it to sharpen continuously by adapting to the workpiece material, thereby extending the tool's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cutting element is used continuously to machine workpieces, then productivity is maintained, but the cutting edge wears down and becomes dull, reducing manufacturing precision and eventually stopping material removal
Solution Approach 1:
The patent applies self-sharpening where the cutting element continuously removes material from itself through controlled rubbing against the workpiece, recovering its sharpness. The wear process is harnessed beneficially to maintain the cutting edge geometry, transforming the harmful wear effect into a useful self-sharpening mechanism that extends tool life while maintaining productivity and precision
Solution Approach 2:
The cutting element performs self-sharpening without external intervention. By applying a controlled rubbing force against the workpiece surface, the cutting edge automatically regenerates its sharp geometry through material removal, eliminating the need for external sharpening operations and enabling continuous productive use
2Manufacturing precision
If the cutting element is replaced frequently to maintain sharpness, then manufacturing precision is maintained, but productivity decreases due to replacement time and material waste increases
Solution Approach 1:
Instead of discarding the cutting element when it becomes dull, the patent recovers its sharpness through self-sharpening. The controlled wear process continuously regenerates the cutting edge geometry, eliminating the need for frequent replacements and reducing material waste while maintaining manufacturing precision
Solution Approach 2:
The self-sharpening mechanism ensures continuous useful action by maintaining the cutting edge sharpness throughout the tool's service life. The rubbing force continuously removes material from the cutting edge, ensuring it remains sharp without interruption to the machining process, thereby eliminating downtime for replacement and maximizing productivity
3Manufacturing precision
If a rubbing force is applied to sharpen the cutting edge, then the cutting element is resharpened, but the force increases orthogonally to the cutting edge, reducing chip thickness and material removal rate
Solution Approach 1:
The patent dynamically adjusts the rubbing force based on the cutting element's wear state. The rubbing force is applied only when needed for self-sharpening and is modulated to prevent excessive orthogonal force that would reduce chip thickness. This dynamic control maintains an optimal balance between sharpness recovery and material removal rate
Solution Approach 2:
The patent changes the parameters of the rubbing force, specifically controlling its magnitude and direction relative to the cutting edge. By adjusting the force parameters to act primarily in the direction that removes material from the cutting edge rather than orthogonally, the system maintains both sharpness and adequate chip thickness for productive machining
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method extends the service life of cutting elements, reducing the need for frequent replacements and resulting in significant cost savings by maintaining effective material removal until the cutting element can no longer be sharpened.
Implementation Method 1
The force Fo is constantly monitored by at least one sensor in the machining tool. When an increased force Fo' and thus a reduced chip thickness h' is reached
Implementation Method 2
If a force Fo' is increased compared to the force Fo and thus a chip thickness h' is reduced, this can be detected by at least one sensor in the machining tool. It is also possible to dispense with a sensor if an essentially elastic component is used as the actuator. For example, a spring element, such as a disc spring, a metal foam, or another resilient structure, can be used as the actuator
Implementation Method 3
In this case, this causes it to compress. A restoring force of the spring then acts against the force Fo'. If the restoring force of the spring element corresponds to the force Fo'
Implementation Method 4
The machining tool has at least one cutting element that removes the excess material. The at least one cutting element is guided with its cutting edge along a surface of the material to be machined. The force Fo is defined as a force perpendicular to the cutting velocity vector in the plane orthogonal to the tool and acting perpendicular to the cutting edge of the cutting element
Implementation Method 5
This effect is subsequently referred to as self-sharpening. This self-sharpening mechanism eliminates the need to replace a cutting element once it becomes dull, as the self-sharpening effect continuously resharpens it
Implementation Method 6
As the tool's service life increases, the cutting edge wears down (step 3). Due to this wear, the initial force Fo increases orthogonally to the cutting edge or cutting element
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
Device and method for force-controlled self-sharpening of a cutting element (3) of a machining tool (2).