An ultra-precision machine tool for machining of the roller has been designed and assembled, and due to the obvious impact which dynamic characteristic of machine tool has on the quality of microstructures on the roller surface, the dynamic characteristic of the existing machine tool is analyzed in this paper, so is the influence of circumstance that a large scale and slender roller is fixed in the machine on dynamic characteristic of the machine tool. At first, finite element model of the machine tool is built and simplified, and based on that, the paper carries on with the finite element mode analysis and gets the natural frequency and shaking type of four steps of the machine tool. According to the above model analysis results, the weak stiffness systems of machine tool can be further improved and the reasonable bandwidth of control system of the machine tool can be designed. In the end, considering the shock which is caused by Z axis as a result of fast positioning frequently to feeding system and cutting tool, transient analysis is conducted by means of ANSYS analysis in this paper. Based on the results of transient analysis, the vibration regularity of key components of machine tool and its impact on cutting process are explored respectively.
In this paper, a four-axis ultra-precision lathe for machining large-scale drum mould with microstructured surface is
presented. Firstly, because of the large dimension and weight of drum workpiece, as well as high requirement of
machining accuracy, the design guidelines and component parts of this drum lathe is introduced in detail, including
control system, moving and driving components, position feedback system and so on. Additionally, the weight of drum
workpiece would result in the structural deformation of this lathe, therefore, this paper analyses the effect of structural
deformation on machining accuracy by means of ANSYS. The position change is approximately 16.9nm in the
X-direction(sensitive direction) which could be negligible. Finally, in order to study the impact of bearing parameters on
the load characteristics of aerostatic journal bearing, one of the famous computational fluid dynamics(CFD) software,
FLUENT, is adopted, and a series of simulations are carried out. The result shows that the aerostatic spindle has superior
performance of carrying capacity and stiffness, it is possible for this lathe to bear the weight of drum workpiece up to
1000kg since there are two aerostatic spindles in the headstock and tailstock.