Machine Tool Positioning via Electrical Voltage Detection
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Solution Overview
Problem
Current methods for determining the position of a work piece and tool in machine tools are limited by inaccuracies caused by the exchange of automatic probing devices and deviations due to non-parallel spindle positioning and tilting, which can lead to damage and inaccuracies during machining.
Innovation Solution
A method involving the application of an electrical voltage between the work piece and tool, with the tool inserted into a rotatable spindle shaft, allowing for precise detection of contact and positioning determination through changes in voltage or current flow, enabling direct probing with the machining tool to avoid damage and ensure accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an automatic probing device is used to determine the position of the work piece, then the measurement precision is improved, but the device complexity increases and additional sources of error are introduced through tool holder exchange
Solution Approach 1:
The invention extracts the probing function from a separate automatic probing device and integrates it directly into the machining tool itself. The machining tool serves dual purposes: both for material removal and for position determination through contactless measurement, eliminating the need for separate probing equipment and the associated tool holder exchanges.
Solution Approach 2:
The machining tool is given multi-functionality by enabling it to perform both machining operations and position determination. The same tool that removes material also performs contactless measurements using electromagnetic radiation, eliminating the need for separate probing devices and reducing overall system complexity.
2Manufacturing precision
If the spindle is positioned exactly in parallel with the displacement direction, then the manufacturing precision is improved, but the ease of operation decreases due to stricter positioning requirements
Solution Approach 1:
The invention implements feedback by using the contactless measurement data to detect actual deviations from the ideal parallel positioning. The system measures the work piece geometry during machining and uses this information to identify and compensate for spindle positioning errors, allowing operation with less strict initial positioning while maintaining high precision.
Solution Approach 2:
The invention changes the measurement parameters by using contactless electromagnetic radiation-based measurement instead of mechanical contact. This allows for real-time detection of positioning deviations and enables dynamic compensation, transforming the rigid requirement for perfect parallel positioning into a flexible system that can adapt to actual positioning conditions.
3Measurement precision
If the length of the automatic probing device corresponds to the length of the machining tool, then the measurement precision is improved, but the adaptability decreases due to strict length matching requirements
Solution Approach 1:
The contactless measurement system provides feedback on the actual position and geometry of the work piece, allowing the system to compensate for differences in tool length. The measurement data is used to calculate correction values that account for varying tool lengths, enabling accurate positioning regardless of the specific tool used.
Solution Approach 2:
The invention changes the approach from fixed geometric constraints to dynamic parameter adjustment. Instead of requiring fixed tool lengths, the system uses electromagnetic radiation-based measurement to detect actual positions and automatically adjusts measurement and machining parameters to compensate for length variations, providing full adaptability across different tool lengths.
4Ease of operation
If minimal tilting of the spindle occurs, then the ease of operation is improved, but the manufacturing precision deteriorates due to offset between probing and machining procedures
Solution Approach 1:
The contactless measurement system continuously monitors the actual position and orientation of the work piece during machining. When minimal tilting or positioning deviations occur, the system detects these through electromagnetic radiation measurements and provides feedback for real-time compensation, maintaining precision even with relaxed positioning tolerances.
Solution Approach 2:
The invention replaces mechanical contact-based probing with electromagnetic radiation-based contactless measurement. This substitution eliminates the mechanical coupling between probing and machining procedures, allowing the system to tolerate minimal spindle tilting without creating offsets, as the electromagnetic field can detect positions without being affected by mechanical alignment constraints.
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 allows for accurate and damage-free probing of work pieces, eliminating inaccuracies from auxiliary devices and enabling continuous zero-point correction during machining, improving precision and efficiency by directly using the machining tool for position determination.
Implementation Method 1
applying an electrical voltage between the work piece and the tool and displacing the tool and the work piece with respect to one another. If a contact occurs between the tool and the work piece, the method further comprises determining a change in the applied voltage or a resulting current flow between the work piece and the tool
Data Source
AI summary
The invention relates to a method for determining a position of a work piece and of a tool in a machine tool, in which a work piece is clamped at the machine tool, in which the tool is subsequently inserted into a rotatable spindle shaft by means of a tool holder and the spindle shaft is set into rotation, in which an electrical voltage is applied between the work piece and the tool, in which the tool and the work piece are displaced with respect to one another, and in which a variation in the applied voltage is determined in the event of a contact between the tool and the work piece, and the respective position of the work piece and/or of the tool is determined and recorded in a computing program for control/regulation of the machining of the work piece.