| "High-end CNC machine tools and basic manufacturing equipment" is one of the 16 major projects from National long-term Scientific and Technological Development Plan(2006 to 2020),and also the paradigm of equipment manufacturing industry.However,due to the integrated non-linear effects of multiple factors,such as the structure,temperature,thermal deformation and so forth,there are a variety of errors produced on the machine which conversely causes some side effects on the quality of workpieces in the process.Therefore,the machine design process is required to do some research on its special characteristics,and employs the relevant theory and technology to effectively reduce or avoid the negative factors that may put adverse effects on the performance of machines.Coupled with more stringent requirements for the machine tool resulted from the new industry development,the international research strength is on the way to converge and integrate with the increasingly heated subject.In recent years,the techniques of thermal error compensation has become an important basis and necessary branch for the research of machine thermodynamics,and the spindle system is the key component to the CNC machining centers,also a main internal heating source,thus its thermal deformation will seriously affect the machining precision.At the same time,in terms of the complex,high-speed,sophisticated modern CNC machine tool and the future machine with the feature of high flexibility,ultra-high speed,ultra-precision and high intelligence,their thermodynamic characteristic parameters and compensation effect will be the key index which can evaluate its performance,quality of products and processing products.This thesis begins with the introduction of domestic and international situation and development trend of thermal error compensation technology,taking the spindle system of the TX1600G composite boring and milling machining center as the object of this research,analyzing its structure characteristics and the main internal heating source;The thermal parameters and boundary conditions of the spindle was discussed based on the heat-structural coupling related theory and the finite element theory for finite element analysis,thus a simplified three-dimensional entity model of the spindle system was established with the help of the Solidworks software,and the temperature field change was simulated by the ANSYS finite element analysis software,then the time when reaching to the steady state was determined after adopting thermal-structure coupling method to simulate the variation of thermal deformation;Based on three groups of experiments,three kinds of working conditions of temperature field and deformation situation,the temperature and thermal error measurement and acquisition system was developed independently,thus its inner relationship was analyzed and the rationality and validity of the finite element thermal analysis were verified;The compensation models of multiple linear regression and wavelet neural network were established to make a comparison of the compensate effect,the results showed that wavelet neural network could express the relationship between the temperature and thermal error more better.In conclusion,the thesis,which focuses on the topic of the thermodynamic characteristics and compensation technology of spindle system,was studied on finite element simulation,thermal experimental measurement and compensation systematically taking the spindle of TX1600G Boring-milling machining center as research object.It illustrates that the thermal error compensation techniques play a vital role in improving the processing and positioning precision of the spindle system,therefore,it is significant in engineering and have important reference significance to the innovation development of machine tool industry in the new circumstances. |
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