Stepped Reference Body for 3-Axis Machine Tool Error Compensation
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Solution Overview
Problem
Existing 3-axis machine tools suffer from significant geometric inaccuracies due to overlapping deviations in linear and rotational axes, leading to undesirable impacts on working accuracy, which existing measuring methods and tools are inefficient in addressing.
Innovation Solution
A measuring body with a square base plate and protruding triangular walls, featuring rows of holes and reference surfaces, is used to determine geometric deviations, allowing for precise compensation of linear and perpendicularity errors, and a control unit adjusts the machine tool's geometry based on target-actual comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measuring methods are used to check geometric deviations of 3-axis machine tools, then measurement accuracy can be achieved, but the measurement process is time-consuming and complex
Solution Approach 1:
The measuring body is pre-manufactured with precisely defined geometric features (holes, edges, surfaces) whose positions and dimensions are known in advance. This preliminary preparation of reference features enables rapid measurement without requiring complex setup or calculation procedures during the actual measurement process.
Solution Approach 2:
The measuring body creates a simplified geometric model or copy of the machine tool's working space with defined reference features. Instead of measuring the complex machine tool structure directly, the measurement is transferred to this simplified replica, reducing measurement complexity and time while maintaining accuracy.
2Manufacturing precision
If comprehensive geometric error compensation is implemented for all 21 possible deviations, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The 21 geometric deviations are segmented into two categories: linear deviations (18 errors from three linear axes) and perpendicularity deviations (3 errors between axes). The measuring body is designed to measure these separately, allowing systematic compensation of each category independently, thereby reducing overall system complexity while maintaining comprehensive error correction.
Solution Approach 2:
The measuring body extends measurement into the third dimension (Z-direction) with stepped features at different heights. This dimensional extension allows simultaneous measurement of multiple geometric parameters (linear deviations in X-Y plane and perpendicularity deviations involving Z-axis) in a single setup, reducing complexity compared to separate measurements.
3Reliability
If a rigid body model with 21 geometric error parameters is used, then measurement completeness is achieved, but the measuring body structure becomes complex and costly
Solution Approach 1:
The measuring body is designed as a universal artifact that can measure multiple types of geometric deviations (linear and perpendicularity errors) simultaneously using a single structure. The combination of holes, edges, and stepped surfaces enables the same measuring body to be used for comprehensive error measurement without requiring multiple specialized fixtures, thereby reducing complexity and cost.
4Productivity
If rapid error compensation is implemented, then productivity is improved, but measurement and correction accuracy may be compromised
Solution Approach 1:
The measuring body's reference features (hole positions, edge locations, surface heights) are pre-calculated and stored as target values. During measurement, the control unit simply compares actual measured values against these pre-stored targets and applies predetermined correction values, enabling rapid compensation without complex real-time calculations that would slow down the process.
Data Source
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AI summary
The invention relates to a measuring body for verifying geometrical deviations in a 3-axis machine tool (1), comprising a base plate (20), a first wall (21) which is arranged on the base plate (20) and projects perpendicularly from the base plate (20), a second wall (22) which is arranged on the base plate (20) and projects perpendicularly from the base plate (20), wherein a first row of holes (23) and a second row of holes (24) are formed in the base plate (20), wherein the first wall (21) has, at an upper, exposed region, a stepped region (25) with a plurality of steps (25a), and wherein the second wall (22) has, at an upper exposed region, a stepped region (25) with a plurality of steps (25a). The invention further relates to a 3-axis machine tool having a measuring body of this kind and to a method for verifying and compensating geometrical deviations of the 3-axis machine tool.