Batch Machining Compensation Using Measured Piece Deviations
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Solution Overview
Problem
Machine tools in batch production face non-repeatability due to internal wear and external environmental factors, leading to quality inconsistencies in machined pieces, which existing control loops struggle to address effectively.
Innovation Solution
A batch production system and method that modify the volumetric compensation data of a machine tool based on real-time measurement data from machined pieces, allowing for continuous improvement of machining accuracy by adjusting compensation values for both intrinsic and extrinsic errors, without requiring changes to the NC program or tool compensation values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the NC program is modified to change d_Command to compensate for diameter deviations, then the machining accuracy is improved, but the system complexity increases due to the need to understand and automatically adjust multiple programming approaches
Solution Approach 1:
The patent extracts the compensation function from the complex NC program modification approach and isolates it into a dedicated tool compensation value (d_ToolComp). This single parameter can be adjusted independently without needing to understand or modify the entire NC program structure, thereby reducing control loop complexity while maintaining machining accuracy.
Solution Approach 2:
The patent changes the approach from modifying program parameters (d_Command) to modifying tool parameters (d_ToolComp). This parameter substitution simplifies the control loop because tool compensation values are standardized and machine-specific, whereas NC programming approaches vary significantly between manufacturers and applications.
2Manufacturing precision
If the tool compensation value d_ToolComp is reduced to increase the machining diameter, then the machining accuracy is improved, but this approach is limited by machine-specific configurations and wear states
Solution Approach 1:
The patent implements dynamic compensation by continuously updating the tool compensation value (d_ToolComp) based on real-time measurements of actual machining results. Instead of using a static compensation value, the system adapts the compensation dynamically to account for changing machine tool conditions such as wear and thermal expansion, thereby maintaining high adaptability and machining accuracy throughout the production process.
Solution Approach 2:
The patent introduces a feedback mechanism where the actual machining results are measured and used to automatically adjust the tool compensation value. This closed-loop control ensures that the compensation remains accurate despite variations in machine tool state, environmental conditions, and tool wear, significantly improving both adaptability and versatility across different machining scenarios.
3Adaptability or versatility
If volumetric compensation is configured to correct intrinsic machine errors, then the general validity of compensation is improved, but the process becomes cumbersome and expensive requiring specialized hardware
Solution Approach 1:
The patent enables the machine tool to perform its own volumetric compensation using standard, built-in measurement capabilities rather than requiring specialized external hardware. The system automatically measures its own machining accuracy and adjusts compensation values accordingly, making the compensation process self-service and eliminating the need for expensive specialized equipment while maintaining general validity across different machining operations.
Data Source
AI summary
A batch production system comprising a machine tool for consecutively machining a batch of workpieces into machined pieces, the machine tool comprising a workpiece support configured for supporting the workpieces, a cutting tool, a movement system configured for providing a relative movement between the cutting tool and the workpiece support with at least two degrees of freedom, a control unit configured for controlling the movement system based on numerical control data and compensation data for compensating volumetric positioning errors of the movement system. The numerical control data are based on nominal geometry data representing a target piece that is desired to be achieved when machining the batch of workpieces into the machined pieces.