Correlating Surface Functionality with Machining Conditions in Precision Machining Processes

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.

A Framework of a Surface Generation Model in Fast Tool Servo (FTS) Machining of Optical Microstructures

2007 ◽  
Vol 364-366 ◽  
pp. 1274-1279
Author(s):  
Tsz Chun Kwok ◽  
Chi Fai Cheung ◽  
Suet To ◽  
Wing Bun Lee
Keyword(s):  
Surface Topography ◽  
Optimization Model ◽  
Tool Path ◽  
Rotational Frequency ◽  
Cutting Conditions ◽  
Surface Generation ◽  
Tool Geometry ◽  
Generation Model ◽  
Fast Tool Servo ◽  
Topography Model

In this paper, a framework of surface generation model in the fast tool servo (FTS) machining of optical microstructures will be described. The integrated model is totally composed of a tool path generator (TPG), a surface topography model (STM) and an optimization model (OM). To develop the tool path generator, two parts should be involved. The first part is the tool path generated based on cutting conditions such as the feed rate and spindle speed, the geometry of optical microstructures, and diamond tool geometry. Another part is the synchronized motion generated by the tool actuation of the FTS at a bandwidth higher than the rotational frequency of the spindle. The surface topography model will be generated based on the TPG and used to predict the technological aspects of FTS machining. It takes into the account the kinematic and dynamic characteristics of the cutting process. The former includes the tool path generated by the tool path generator. The later includes the relative vibration between the tool and the workpiece caused by the axial error motion of the spindle as well as the synchronized motion of the FTS system. The optimization model will be undertaken by an iterative algorithm, which will be developed based on the TPG and STM. The OM will be expected to output the verified tool path, the suggested optimum cutting conditions, and the diagrams with predicted cutting performance characteristic and process parameters being investigated. Eventually, the successful development of this surface generation model can contribute for the knowledge of ultra-precision machining with FTS and the further development of the performance of the machining system.

Predictive Surface Generation and Characterization for Cylindrical Turning Processes

2005 ◽  
Author(s):  
Yashpal Kovvur ◽  
Hemant Ramaswami ◽  
Sam Anand
Keyword(s):  
Process Parameters ◽  
Surface Characterization ◽  
Tool Path ◽  
Surface Generation ◽  
Generation Model ◽  
Machining Parameters ◽  
Machined Surface ◽  
Motion Error ◽  
Simulation Based ◽  
Manufacturing Errors

This paper presents a generalized simulation based approach for generation and characterization of turned surfaces based on process parameters and manufacturing errors. The presented model shows that with proper analytical modeling along with appropriate process monitoring system (force signals, vibration signals, spindle motion error signals etc.,) a comprehensive surface generation model can be developed. First, the tool nose geometry and cutting-force induced vibrations are superimposed to obtain the cutting tool path. Next, the information obtained from spindle motion errors is used to analytically formulate the position of each point on the machined surface. Regression models are fit to establish the relationship between form error / surface roughness and input parameters. The simulation-based approach presented here provides a quantitative bridge between process parameters/manufacturing errors and surface characterization metrics. Such a scheme would allow manufacturing engineers to pre-select processes, parameters, and capable machines to achieve design specification. This model will allow engineers to proactively control the influence of machining parameters on product quality through computer simulation, and, thus, “do things right the first time.”

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

1991 ◽  
Vol 113 (2) ◽  
pp. 145-153 ◽  
Author(s):  
G. M. Zhang ◽  
S. G. Kapoor
Keyword(s):  
Surface Topography ◽  
Random Excitation ◽  
Surface Generation ◽  
Distribution Model ◽  
Excitation System ◽  
Machined Surface ◽  
Spiral Trajectory ◽  
Vibratory Motion ◽  
Texture Generation ◽  
Simulation Results

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.

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

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.

scholarly journals Machinability and Surface Generation of Pd40Ni10Cu30P20 Bulk Metallic Glass in Single-Point Diamond Turning

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 4 ◽  
Author(s):  
Jie Xiong ◽  
Hao Wang ◽  
Guoqing Zhang ◽  
Yanbing Chen ◽  
Jiang Ma ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Tool Path ◽  
Single Point ◽  
Chip Morphology ◽  
Diamond Turning ◽  
Surface Generation ◽  
Workpiece Material ◽  
Machined Surface

Pd40Ni10Cu30P20 bulk metallic glass (BMG) is widely used in industrial fields due to its excellent oxidation resistance, corrosion resistance, and thermal stability. However, the lack of research on the machinability and cutting performance of BMG using single-point diamond turning (SPDT) limits its application for engineering manufacturing. In the present research, a series of turning experiments were carried out under different cutting parameters, and the machinability reflected by the quality of machined surface, chip morphology, and tool wear were analyzed. Based on the oxidation phenomenon of the machined surface, a molecular dynamics (MD) simulation was conducted to study the mechanism and suppression of the machined surface oxidation during the cutting. The results show that: (1) The Pd-based BMG had good machinability, where the machined surface roughness could go down to 3 nm; (2) irregular micro/nanostructures were found along the tool path on the outer circular region of the machined surface, which greatly affected the surface roughness; and (3) the cutting heat softened the workpiece material and flattened the tool marks under surface tension, which improved the surface quality. This research provides important theoretical and technical support for the application of BMG in optical mold manufacturing.

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

2019 ◽  
Vol 233 (12) ◽  
pp. 2330-2344 ◽  
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.

scholarly journals A Study of Nanometric Surface Generation on Tungsten Carbide Using a Micro Polycrystalline Diamond End Mill

2012 ◽  
Vol 6 (4) ◽  
pp. 547-553 ◽  
Author(s):  
Kazuo Nakamoto ◽  
◽  
Tojiro Aoyama ◽  
Kazutoshi Katahira ◽  
Peter Fonda ◽  
...  
Keyword(s):  
Tool Wear ◽  
Tungsten Carbide ◽  
Value Added ◽  
Micro Milling ◽  
Surface Generation ◽  
End Mill ◽  
High Quality ◽  
Machined Surface ◽  
Machining Conditions ◽  
Custom Made

The demand for high quality micro-scale molds for the production of high value-added miniature parts is rapidly growing. The fabrication of such molds requires highly productive and high quality micro milling of hard and brittle materials, such as tungsten carbide (WC). Such micro milling processes have not yet been studied well, however, so their fundamental nature is not yet well understood. This paper reports the results of a study on the basic nature of the micro milling process when WC is machined with a custom made PCD (poly-crystalline diamond) micro tool. The study includes the design and fabrication of a custom micro end mill tool with a single cutting edge, experimental procedures to find the optimal machining conditions for high quality surface generation, and an evaluation of the quality of the machined surface in relation to tool wear. The results of the experimental study indicate that machining conditions exist for the generation of a surface with nanometer-level roughness. Normal tool wear is maintained over long cutting lengths while tool wear grows continuously on the axial clearance face of the end mill.

scholarly journals Theoretical and Experimental Investigation of Surface Topography Generation in Slow Tool Servo Ultra-Precision Machining of Freeform Surfaces

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2566 ◽  
Author(s):  
Duo Li ◽  
Zheng Qiao ◽  
Karl Walton ◽  
Yutao Liu ◽  
Jiadai Xue ◽  
...  
Keyword(s):  
Surface Topography ◽  
Tool Path ◽  
Tool Path Generation ◽  
Surface Generation ◽  
Precision Machining ◽  
Path Generation ◽  
Freeform Surfaces ◽  
Ultra Precision ◽  
Slow Tool Servo ◽  
Radius Compensation

Freeform surfaces are featured with superior optical and physical properties and are widely adopted in advanced optical systems. Slow tool servo (STS) ultra-precision machining is an enabling manufacturing technology for fabrication of non-rotationally symmetric surfaces. This work presents a theoretical and experimental study of surface topography generation in STS machining of freeform surfaces. To achieve the nanometric surface topography, a systematic approach for tool path generation was investigated, including tool path planning, tool geometry selection, and tool radius compensation. The tool radius compensation is performed only in one direction to ensure no high frequency motion is imposed on the non-dynamic axis. The development of the surface generation simulation allows the prediction of the surface topography under various tool and machining variables. Furthermore, it provides an important means for better understanding the surface generation mechanism without the need for costly trial and error tests. Machining and measurement experiments of a sinusoidal grid and microlens array sample validated the proposed tool path generation and demonstrated the effectiveness of the STS machining process to fabricate freeform surfaces with nanometric topography. The measurement results also show a uniform topography distribution over the entire surface and agree well with the simulated results.

Investigation of the tool-tip vibration and its influence upon surface generation in flycutting

2013 ◽  
Vol 228 (12) ◽  
pp. 2162-2167 ◽  
Author(s):  
Yingchun Liang ◽  
Wanqun Chen ◽  
Chenhui An ◽  
Xichun Luo ◽  
Guoda Chen ◽  
...  
Keyword(s):  
Flat Surface ◽  
Dynamic Performance ◽  
Machining Process ◽  
Surface Generation ◽  
Dominant Factor ◽  
Generation Model ◽  
Machined Surface ◽  
Workpiece Surface ◽  
Surface Machining ◽  
Machining Force

Flycutting is a major machining process for flat-surface machining, which is a typical intermittent-machining process. This paper is dedicated to study the influence of the intermittent-machining force on the workpiece surface generation. In the present study, some defects are identified on the machined surface and found to be corresponded to the tool-tip vibration by the dynamic analysis and the surface-generation simulation. A theoretical model is proposed to capture the dominant factor based on the characteristic. It reveals that the defects are attributed to the changing period of the intermittent-machining force and the dynamic performance of the machine tool. Hence, a surface-generation model is proposed to take account of the tool-tip vibration and the changing of the cutting locus. The simulation results have been found to agree well with the experimental results.

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