Tool Arm Force Sensor Layout for Accurate Cutting Force Measurement
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Solution Overview
Problem
Existing cutting machines face inaccuracies in measuring tool force due to the placement of force transducers away from the cutting wedge, leading to indirect measurement of mechanical tension influenced by machine part dimensions and mass, resulting in less precise tool force measurement.
Innovation Solution
The placement of a force transducer within the tool arm, specifically between the upper and lower arms, allows for direct measurement of tool force with minimal damping, enabling precise alignment and movement of tools while maintaining the external dimensions of conventional cutting machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the force transducer is placed remotely in a machine component, then the measurement system is easier to install, but the measurement precision deteriorates due to indirect measurement of mechanical stress influenced by component dimensions and mass
Solution Approach 1:
The force transducer is extracted from the conventional remote mounting location and repositioned directly at the cutting wedge where the force acts. This extraction from the indirect measurement location eliminates the interference of machine component dimensions and mass, enabling direct measurement of the tool force with significantly improved accuracy.
Solution Approach 2:
The force transducer serves as an intermediary element placed between the cutting wedge and the tool holder, directly in the force transmission path. This intermediary position allows the transducer to measure the actual tool force without the distorting influence of other mechanical components, resolving the contradiction between easy installation and measurement precision.
2Measurement precision
If the force transducer is placed directly at the cutting wedge, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The force transducer is merged with the tool holder structure, integrating the measurement function into the existing tool changing mechanism. This merging approach allows direct measurement at the cutting wedge while avoiding additional complex mounting structures, thus improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The tool holder is designed to serve multiple functions: it holds the cutting wedge, enables tool changing, and now also houses the force transducer for measurement. This multi-functionality reduces the need for separate measurement infrastructure, thereby improving measurement precision while keeping the overall device complexity manageable.
3Productivity
If the tool holder is moved frequently for tool changes and alignment, then the productivity improves, but the measurement stability deteriorates due to repeated positioning and movement
Solution Approach 1:
The force transducer is pre-installed and calibrated in the tool holder before tool changes occur. This preliminary setup ensures that the measurement system is ready and stable, maintaining measurement stability even as tools are frequently changed and the tool holder is moved for alignment and positioning operations.
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 solution provides a precise and cost-effective measurement of tool force, reducing wear on cutting wedges and improving surface quality and dimensional accuracy of workpieces by accurately transmitting tool force through the tool arm.
Implementation Method 1
The machining machine has a drive unit, a machine arm, at least one force transducer. The force sensor is located inside a two-part tool arm, which saves space and is also cost-effective, as the predetermined external dimensions of a conventional tool arm are retained
Data Source
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AI summary
The invention relates to a cutting machine (1) for machining a workpiece (9), which machining is carried out in a temporal sequence of production steps by means of a plurality of required tools (14), the cutting machine comprising: a tool holder (13) for holding the required tools (14); a tool arm (11) for fastening the tool holder (13) to a drive unit (10), which drive unit (10) moves the tool arm (11), by means of which moving of the tool arm (11) one of the required tools (14) can be oriented on a workpiece (9) in each production step, the tool arm (11) having an upper arm (11.1) and a lower arm (11.2), the upper arm (11.1) and the lower arm (11.2) being separate units and being mechanically interconnected, the upper arm (11.1) being fastened to the drive unit (10), the lower arm (11.2) being fastened to the tool holder (13), and at least one force sensor (12.1, 12.2) being arranged spatially between the upper arm (11.1) and the lower arm (11.2), which force sensor (12.1, 12.2) can measure, in the direct line of force, a tool force (Kw) applied by one of the required tools (14) during the machining of a workpiece (9).