Dynamic Generation of Machined Surfaces, Part 2: Construction of Surface Topography

In Part 1 of these two-part papers, a normal distribution model has been formulated to describe the random excitation system present during machining. Part 2 presents a methodology to dynamically generate the surface topography under the random excitation environment through computer simulation. The proposed methodology uses the tool vibratory motion along with the tool geometrical motion to construct the topography of a machined surface. Both experimental and simulation results confirm that when a small feed is used, the influence of the spiral trajectory of tool geometrical motion on the surface generation decays dramatically and the random excitation system, on the opposite, is strengthened playing a significant role in surface texture generation.

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A prediction model of the surface topography due to the unbalance of the spindle system in ultra-precision fly-cutting machining

Advances in Mechanical Engineering ◽

10.1177/1687814017747145 ◽

2018 ◽

Vol 10 (1) ◽

pp. 168781401774714

Author(s):

Dongju Chen ◽

Xianxian Cui ◽

Ri Pan ◽

Jinwei Fan ◽

Chenhui An

Keyword(s):

Prediction Model ◽

Surface Topography ◽

Rotation Speed ◽

Surface Generation ◽

Machining Accuracy ◽

Machined Surface ◽

Spindle System ◽

Fly Cutting ◽

Ultra Precision ◽

Aerostatic Spindle

In ultra-precision fly-cutting machining, the aerostatic spindle is the key component, which has significant influence on the machined surface quality. The unbalanced spindle directly affects the machining accuracy. In this article, a prediction model of machining surface topography is proposed which involves the effect of the gas film performance of spindle in microscale. With the Weierstrass function, unstable transient response of the aerostatic spindle system is derived by the motion model of the spindle, which response signal represents the surface profile in the ultra-precision machining. Meanwhile, the experiment is performed with different rotation speed of the spindle. And the effect of the unbalanced aerostatic spindle on the surface generation is discussed in time and frequency domain. The conclusion shows that the similar cyclical surface ripple of the workpiece is independent of the spindle speed, and the rotation speed of the spindle and unbalanced spindle directly affects the machining surface topography. This study is quite meaningful for deeply understanding the influence rule of spindle unbalanced error from the viewpoint of machined surface and vibration frequency.

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Correlating Surface Functionality with Machining Conditions in Precision Machining Processes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.471-472.112 ◽

2004 ◽

Vol 471-472 ◽

pp. 112-116

Author(s):

X.C. Luo ◽

K. Cheng ◽

R. Ward

Keyword(s):

Surface Topography ◽

Tool Path ◽

Surface Generation ◽

Force Model ◽

Generation Model ◽

Machining Processes ◽

Machined Surface ◽

Surface Functionality ◽

Precision Turning ◽

Machining Conditions

This paper attempts to correlate surface functionality generation with machining conditions by computer simulation and machining trials. The linear and nonlinear machining conditions, such as feed rate, built-up-edge, shear- localized chip formation, regenerative chatter are modelled in the light of their physical features. They are the inputs to the integrated surface topography generation model. The dynamic tool path is calculated through the dynamic cutting force model and surface response model. The surface is generated by transforming the tool profile onto the workpiece surface along the dynamic tool path. All of these models are integrated in a user-friendly Matlab Simulink environment. On the basis of the Simulink model, the dynamic simulation is performed to predict the 3D machined surface topography and its functionality. The simulation results have been validated by precision turning trials. The spectrum analysis of the machining dynamics and surface topography shows that surface generation is highly affected by the nonlinear factors in precision turning process. A case study shows the feasibility of generating some functional surface for some product/component through controlling machining variables.

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Theoretical prediction and experimental verification of the unbalanced magnetic force in air bearing motor spindles

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405419838656 ◽

2019 ◽

Vol 233 (12) ◽

pp. 2330-2344 ◽

Cited By ~ 1

Author(s):

Quanhui Wu ◽

Yazhou Sun ◽

Wanqun Chen ◽

Qing Wang ◽

Guoda Chen

Keyword(s):

Surface Topography ◽

Surface Quality ◽

Magnetic Force ◽

Research Work ◽

Diamond Turning ◽

Surface Generation ◽

Air Bearing ◽

Machined Surface ◽

Spindle Shaft ◽

Ultra Precision

Dynamic vibrations of air bearing motor spindles have significant influence on the surface quality in ultra-precision machining. In this article, the influence of the vibration caused by the unbalanced magnetic force on the diamond turning is investigated on the basis of the theoretical and experimental method. A permanent magnet motor model (10 poles and 12 slots) is built and then simulated to gain a periodic unbalanced magnetic force. The effects of unbalanced magnetic force on the inclination of the spindle shaft is analyzed, which would affect the surface quality of the workpiece, and the surface topography of the workpiece is predicted during an unbalanced magnetic force acting on air bearing motor spindle. The theoretical analysis and experimental turning results validate that the angle between the direction of unbalanced magnetic force and the feed direction has a certain relationship with the profile of the machined surface. Also, under different turning speeds and directions, the surface topography of the machined workpiece shows a 10-cycle-per-revolution pattern, which has good agreement with the simulations of periodic unbalanced magnetic force. This research work provides a theoretical foundation for the fault diagnosis of air bearing motor spindle caused by motor rotor eccentricity and its effect on surface generation in turning.

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Simulation of Surface Topography Formed During the Intermittent Turning Processes

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2896375 ◽

1991 ◽

Vol 113 (2) ◽

pp. 273-279 ◽

Cited By ~ 7

Author(s):

G. M. Zhang ◽

S. Yerramareddy ◽

S. M. Lee ◽

S. C.-Y. Lu

Keyword(s):

Surface Topography ◽

Quantitative Estimate ◽

Qualitative Evaluation ◽

Turning Process ◽

Machined Surface ◽

Workpiece Surface ◽

Vibratory Motion ◽

Intermittent Turning ◽

Geometric Motion

This paper presents a methodology which employs computer simulation to dynamically generate the topography of a surface machined during an intermittent turning process. The methodology is based on a mathematical model that characterizes the intermittent turning process as an alternating sequence of forced and free vibratory motion. The simulation of machining workpieces, with discontinuous geometries of arbitrary shape, is facilitated by representing the workpiece surface as a two-dimensional grid, with an index for each cell in the grid accounting for the feature boundaries. The tool vibratory motion is integrated with the tool geometric motion to form a basis for the construction of surface texture produced during machining. The simulation model not only provides for a qualitative evaluation of the surface accuracy through a graphic visualization of the surface topography, but also provides a quantitative estimate of the roughness quality of the machined surface.

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Modelling of machined surface topography and anisotropic texture direction considering stochastic tool grinding error and wear in peripheral milling

Journal of Materials Processing Technology ◽

10.1016/j.jmatprotec.2021.117065 ◽

2021 ◽

Vol 292 ◽

pp. 117065

Author(s):

Chongyan Cai ◽

Qinglong An ◽

Weiwei Ming ◽

Ming Chen

Keyword(s):

Surface Topography ◽

Peripheral Milling ◽

Machined Surface ◽

Tool Grinding

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Generation mechanism modeling of surface topography in tangential ultrasonic vibration-assisted grinding with green silicon carbide abrasive wheel

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211040609 ◽

2021 ◽

pp. 095440542110406

Author(s):

Yutong Qiu ◽

Jingfei Yin ◽

Yang Cao ◽

Wenfeng Ding

Keyword(s):

Surface Roughness ◽

Surface Topography ◽

Ultrasonic Vibration ◽

Generation Mechanism ◽

Surface Generation ◽

Depth Of Cut ◽

Abrasive Wheel ◽

Grinding Parameters ◽

Conventional Grinding ◽

Ultrasonic Vibration Assisted Grinding

Tangential ultrasonic vibration-assisted grinding (TUAG) has a wide prospect in machining difficult-to-machine materials. However, the surface generation mechanism in TUAG is not fully recovered. This study proposes an analytical model of the surface topography produced by TUAG. Based on the model, the surface topography and roughness are predicted and experimentally verified. In addition, the influence of the grinding parameters on the surface topography is analyzed. The predicted surface topography well coincides with experimental measurements, and the prediction error in surface roughness Ra by the proposed model is less than 5%. Compared with conventional grinding, TUAG produces a surface with more uniform scratches and surface roughness Ra was reduced by up to 27% with the proper parameters. However, the improvement of surface roughness in TUAG is weakened when grinding speed or depth of cut increases. Moreover, the influence of the ultrasonic vibration amplitude on the surface roughness is not monotonous. With the grinding parameters selected in this study, TUAG with an ultrasonic amplitude of 7.5 μm produces the minimum surface roughness.

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