Machining Center Workpiece Table Deformation Compensation
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Solution Overview
Problem
Machining centers face accuracy issues due to geometry deviations caused by workpiece loads, particularly in swiveling and rotating workpieces, which existing solutions struggle to address without additional external measuring and control devices, and are limited in applicability to uniaxial linearly movable workpiece-carrying assemblies.
Innovation Solution
A method that uses a deformation model adjusted via stiffness-relevant input variables to describe the complete deformation behavior of a swiveling and rotating workpiece table, implemented in the machine control system, allowing for automatic position corrections of elastic component deformations without external measuring devices, using electric servomotors to control the workpiece table's movement and calculate correction values based on workpiece mass and center of gravity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a swiveling and rotating workpiece table with large span bridge girder is used, then the machining center can handle heavy workpiece loading and multifunctional machining, but design-related deflections or deformations occur in the hundredths of a millimeter range that reduce processing accuracy
Solution Approach 1:
The patent applies parameter changes by implementing a deformation model with adjustable stiffness-relevant input variables that describe the complete deformation behavior of the workpiece-carrying assembly. The machine control system uses these parameters to calculate and apply position correction values that compensate for elastic component deformations, thereby maintaining manufacturing precision while preserving the multifunctional capability.
2Manufacturing precision
If additional piezoelectric actuators are added to adjust geometric errors, then position correction capability is improved, but device complexity and installation effort increase significantly
Solution Approach 1:
The patent replaces the mechanical piezoelectric actuator system with a computational approach. Instead of adding physical actuators to mechanically adjust geometric errors, the invention uses a deformation model implemented in the machine control system that calculates position correction values based on workpiece mass and center of gravity parameters, thereby achieving position correction without additional mechanical components.
Solution Approach 2:
The patent creates a virtual copy or model of the physical workpiece-carrying assembly in the form of a deformation model. This computational model replicates the deformation behavior of the actual assembly, allowing the control system to predict and compensate for deformations without physically measuring or interfering with the actual components during operation.
3Manufacturing precision
If existing workpiece-carrying assemblies are upgraded with external measuring and control devices, then deformation correction is possible, but the upgrading effort and cost increase greatly
Solution Approach 1:
The patent enables the machine control system to perform deformation correction autonomously using existing components. The deformation model uses parameters such as workpiece mass and center of gravity that are already available from the machine's measurement systems, allowing the system to self-correct deformations without requiring external measuring devices or additional control infrastructure.
4Manufacturing precision
If deformation correction is performed during operation, then machining accuracy is maintained dynamically, but calculation and control complexity increases
Solution Approach 1:
The patent performs preliminary action by calculating position correction values before the actual machining operation begins. The deformation model is adjusted using stiffness-relevant input variables obtained during setup, and correction values are pre-calculated based on the specific workpiece parameters, allowing the system to compensate for deformations throughout the machining process without requiring complex real-time calculations during operation.
Data Source
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AI summary
The method involves adjusting deformation model describing physical conditions of a workpiece-supporting assembly (2) of a machining center (1) based on deformation measurements. The model is implemented as non-variable computing model in a machine controller (11). Position correction values for the controller are calculated with the computing model. Position correction is automatically executed at the assembly by using the correction values such that elastic deformation of the assembly is determined and adjusted in spatial direction by using the controller.