Thermal error reduction based on thermodynamics structure optimization method for an ultra-precision machine tool

2016 ◽  
Vol 88 (5-8) ◽  
pp. 1267-1277 ◽  
Author(s):  
Lijian Sun ◽  
Mingjun Ren ◽  
Haibo Hong ◽  
Yuehong Yin
Author(s):  
Guo-Da Chen ◽  
Ya-Zhou Sun ◽  
Fei-Hu Zhang ◽  
Li-Hua Lu ◽  
Wan-Qun Chen ◽  
...  

Author(s):  
Hao Duan ◽  
Shinya Morita ◽  
Takuya Hosobata ◽  
Masahiro Takeda ◽  
Yutaka Yamagata

Abstract Aspherical or free-form optical surface machining using an ultra-precision machine tool is a common and effective method in precision optics manufacturing. However, this method sometimes causes waviness due to the machine’s motion in mid-spatial frequency (MSF) form deviations. This waviness lowers the quality of the optical surface. To address this problem, we use the waviness of the axial displacement of the ultra-precision machine tool. The waviness is obtained by a non-contact on-machine metrology (OMM) system that measures an optical flat as a correction reference curve, which is used to correct the surface of the workpiece to reduce the effect of waviness in advance. The OMM system consists of a displacement probe and a machine tool axis position capture device. The probe system uses a confocal chromatic probe on an ultra-precision machine tool to evaluate the form deviation of the workpiece with 1 nm resolution. The axis position capture system uses a signal branch circuit of linear scale on each axis from the ultra-precision machine tool. The OMM system is tested in terms of accuracy and repeatability. In comparison to the results of the shaper cutting of an oxygen-free copper (OFC) workpiece with feed-forward correction, we were able to reduce the profile error from 125.3 nm to 42.1 nm in p-v (peak to valley) and eventually also reduced the waviness.


2016 ◽  
Vol 874 ◽  
pp. 531-536 ◽  
Author(s):  
Hao Duan ◽  
Takuya Hosobata ◽  
Masahiro Takeda ◽  
Shinya MORITA ◽  
Yutaka Yamagata

This paper describes a development of a real-time position capturing method in which branched encoder signals are recorded in external data storage, to evaluate motion trajectories of the XYZ table on ultra-precision machine tool. The method allows the capturing with minimal modification to the machine: without any additional sensors. In the previous study we generated a non-axisymmetric aspherical optical element by XZC-axis simultaneous numerical controlled ultra-precision turning process with 2 μm form deviation, the reason of form accuracy degradation wasn’t identified. Using the developed system, motion accuracy of ultra-precision machine tool is confirmed. The machine tool moves along circular trajectory in three coordinate planes (XY, YZ and ZX) respectively. The rotation direction of circle is set clock wise and counter clock wise. The circle processing interpolation command by linear interpolation control code and circular interpolation control code. The results showed the effectiveness of the proposed method for performance evaluations of machine tools, by revealing the influence of trajectory parameters on the magnitudes of quadrant protrusions.


2014 ◽  
Vol 30 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Yingchun Liang ◽  
Wanqun Chen ◽  
Yazhou Sun ◽  
Nan Yu ◽  
Peng Zhang ◽  
...  

2020 ◽  
Vol 14 (3) ◽  
pp. 475-483
Author(s):  
Martin Mareš ◽  
◽  
Otakar Horejš ◽  
Jan Hornych

Achieving high workpiece accuracy is a long-term goal of machine tool designers. Many causes can explain workpiece inaccuracy, with thermal errors being the most dominant. Indirect compensation (using predictive models) is a promising thermal error reduction strategy that does not increase machine tool costs. A modeling approach using transfer functions (i.e., a dynamic method with a physical basis) has the potential to deal with this issue. The method does not require any intervention into the machine tool structure, uses a minimum of additional gauges, and its modeling and calculation speed are suitable for real-time applications that result in as much as 80% thermal error reduction. Compensation models for machine tool thermal errors using transfer functions have been successfully applied to various kinds of single-purpose machines (milling, turning, floor-type, etc.) and have been implemented directly into their control systems. The aim of this research is to describe modern trends in machine tool usage and focuses on the applicability of the modeling approach to describe the multi-functionality of a turning-milling center. A turning-milling center is capable of adequately handling turning, milling, and boring operations. Calibrating a reliable compensation model is a real challenge. Options for reducing modeling and calibration time, an approach to include machine tool multi-functionality in the model structure, model transferability between different machines of the same type, and model verification out of the calibration range are discussed in greater detail.


1999 ◽  
Vol 213 (1) ◽  
pp. 1-9 ◽  
Author(s):  
S R Postlethwaite ◽  
J P Allen ◽  
D G Ford

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