Study on Ultra-Precision Ball Surface Floating Polishing Kinematics Mechanism

The high precision balls are requested in national defense, astronautics and high-tech commercial domain urgently. Conventional precision machining methods are sensitive to uniformity of abrasives and machining environment. After precision machining, there are easily to produce thick damaged layer on the ball surface because of machining stress and chemical conversion. On the basis of the floating polishing mechanism, a new scatheless ultra-precision polishing method of ball surface can solve the problems of abrasives uniformity effectively and damaged layer. In order to ensure that the new polishing method polishes ball surface equally, the appropriate angular velocities of the ball should be selected. This paper sets up the mathematical model about the motion of ball. By analyzing and simulating the relationship of the angular velocities, the best processing parameters are acquired.

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Evaluation of Rotational Speed Control System for Water Driven Spindle With Disturbance Observer

Volume 11: Systems, Design, and Complexity ◽

10.1115/imece2015-51166 ◽

2015 ◽

Author(s):

Akio Hayashi ◽

Yohichi Nakao

Keyword(s):

Control System ◽

Rotational Speed ◽

Disturbance Observer ◽

Speed Control ◽

Precision Machining ◽

Feedback Control System ◽

Speed Control System ◽

Ultra Precision ◽

Rotational Speed Control ◽

The Mathematical Model

In ultra-precision machining to produce various precision products such as lenses or mirrors, the single-point diamond cutting is mainly carried out to achieve the high accuracy and high quality machined surfaces. Thus, the precise rotation accuracy is required to the spindle of the ultra-precision machining tool. The water driven spindle had been developed for the precision machining tool spindle. This spindle is driven by the torque of water flow power. Then, the rotational speed can be controlled by supplied flow rate of water. However, the rotational spindle speed during cutting operation is changed due to the influence of the cutting forces during the machining processes. The change in the rotational speed causes the change in the cutting speed, as a result, it degrades the machined surface quality as well. In order to reveal and reduce the influence of this phenomenon, the mathematical model of the rotational speed control system for water driven spindle was derived. This rotational speed control system consists of the water driven spindle and the flow control valve. From the simulation results using a derived transfer function of the rotational speed control system, it is clarified that the rotational speed changes depending on the external load torque. Then, based on the mathematical model, the feedback rotational speed control system with a conventional P-I controller is designed. The effectiveness of the proposed feedback control system is verified by the turning tests. Furthermore, a disturbance observer to minimize the influence of cutting forces on the rotational speed was added to the feedback control system. As a result, this paper shows the performance of the rotational speed control system.

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Mathematical Modelling of the Stress-Strain Curve for 31VMn12 Ecological Steel

Materiale Plastice ◽

10.37358/mp.17.3.4861 ◽

2017 ◽

Vol 54 (3) ◽

pp. 409-413

Author(s):

Carmen Otilia Rusanescu ◽

Cosmin Jinescu ◽

Marin Rusanescu ◽

Maria Cristiana Enescu ◽

Florina Violeta Anghelina ◽

...

Keyword(s):

Mathematical Modelling ◽

Strain Curve ◽

Torsion Test ◽

Processing Parameters ◽

Stress Strain Curve ◽

Stress Strain ◽

Hollomon Parameter ◽

Relationship Of ◽

The Mathematical Model ◽

The Relationship

In this paper, optimum hot formation processing parameters for 31VMn12 steel were established, the torsion deformation of 31VMn12 steel was investigated at temperatures from 900, 1000, 11000C and strain rates from 0.05 s-1 to 3 s. -1. There were studied the structural aspects of materials, in microstructures by electronic microscopy. The stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zenner-Hollomon parameter. The mathematical model presented in the paper describes the relationship of tension strain, voltage and temperature coefficient 31VMn12 steel at high temperatures. The stress-strain curves determined by the torsion test allowed the calculation of the Zenner-Hollomon parameter corresponding to the maximum stress. By using this parameter has established a set of equations that reproduce completely stress-strain curve, including the hardening, the restoration and dynamic recrystallization area. Comparisons were made between the experimental results and the predicted and confirmed that constitutive equations developed can be used for mathematical modelling and other attempts (forging, compression) and other types of steel.

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Ultra-Precision Machining Technology Based on Dynamic Minimum Thickness of Cut for Machined Single Crystal Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.138-139.1246 ◽

2011 ◽

Vol 138-139 ◽

pp. 1246-1250

Author(s):

Ji Cai Kuai

Keyword(s):

Surface Roughness ◽

Friction Coefficient ◽

Single Crystal ◽

Surface Quality ◽

Cutting Parameters ◽

Precision Machining ◽

Minimum Thickness ◽

Single Crystal Copper ◽

Ultra Precision ◽

Relationship Of

The dynamic minimum thickness of cut for the ultra-precision machining surface quality is important influence. Between tool and the workpiece for the friction coefficient were analysised, the relationship of the friction coefficient and the MTC were discussed, and the MTC and its effects on surface roughness were a theoretical analysised and experimental verification with processed single crystal copper and single crystal aluminum by AFM’s diamond tip. The results show: the MTC of single-crystal copper (single crystal aluminum) is 5.2nm (8.2nm) in stable cutting conditions. Further processing single crystal copper (ingle crystal aluminum) with cutting thickness of 5.2nm (8.2nm), and the surface roughness Ra160nm (Ra110nm) is obtained. So the MTC is evolving with the friction coefficient and the force ratio, theoretical MTC tends to be minimal value then before the adhering effect to reach remarkable. Appropriate adjustments cutting parameters, the cutting process can always micro-cutting phase to reach the steady-thin chip, and no plowing phenomenon. So the surface residues highly were reduced and higher surface quality was achieved.

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An Investigation of Form Compensation in Fabricating Microlens Arrays by Ultra-Precision Fast-Tool-Servo Technology

Materials Science Forum ◽

10.4028/www.scientific.net/msf.532-533.689 ◽

2006 ◽

Vol 532-533 ◽

pp. 689-692 ◽

Cited By ~ 4

Author(s):

Tsz Chun Kwok ◽

Suet To ◽

Chi Fai Cheung ◽

Su Juan Wang ◽

Wing Bun Lee

Keyword(s):

Measurement Data ◽

Precision Machining ◽

High Tech ◽

Fast Tool Servo ◽

Form Error ◽

Microlens Arrays ◽

Ultra Precision ◽

Radius Compensation ◽

Critical Components ◽

Tool Compensation

Microlens arrays are widely used as critical components in a large number of photonics and telecommunication products. The increasing demand for high-tech products provides an expanding room for the development of the micro-fabrication technology. This study presents a tool compensation for correcting the form error of fabricated microlenses in ultra-precision machining with fast-tool-servo (FTS) system. After presentation of optimal cutting conditions deduced on the basis of cutting experiments of microlens arrays, a tool radius compensation method will be proposed and evaluated in this paper. This methodology makes use of form measurement data from a Form Talysurf system to modify the C program employed in the software of ultra-precision machining FTS system – SOP. The form error was successfully reduced after implementation of tool compensation.

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Simulation of Ultra-Precision Machining for Microstructured Surface Based on FTS

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.516.481 ◽

2012 ◽

Vol 516 ◽

pp. 481-486

Author(s):

Ming Zhou ◽

Lin Hua Hu ◽

Guo Jun Dong ◽

Hai Jun Zhang

Keyword(s):

Processing Parameters ◽

Simulation System ◽

Surface Generation ◽

Precision Machining ◽

Work Piece ◽

Vibration Machine ◽

Microstructured Surface ◽

Microstructured Surfaces ◽

Environmental Vibration ◽

Ultra Precision

Based on the ultra precision machine tool, using Matlab/Simulink and considering the linear and nonlinear factors of the processing such as environmental vibration, machine movement, servo control technology, work piece material, cutting force and built-up-edge, the simulation system of ultra precision machining for microstructured surface based on fast tool servo (FTS), which integrated machine control system, machine mechanical system and surface generation, was established and verified by processing sinusoidal microstructured surfaces. The experimental results showed the simulation output errors were 15 % or so, and the simulation system could predict the microstructured surface morphology, optimize the processing parameters and provide support for follow up studies.

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A Self-Established “Machining-Measurement-Evaluation” Integrated Platform for Taper Cutting Experiments and Applications

Micromachines ◽

10.3390/mi12080929 ◽

2021 ◽

Vol 12 (8) ◽

pp. 929

Author(s):

Xudong Yang ◽

Zexiao Li ◽

Linlin Zhu ◽

Yuchu Dong ◽

Lei Liu ◽

...

Keyword(s):

Three Dimensional ◽

Precision Machining ◽

Two Dimensional ◽

Dimensional Image ◽

Two Dimensional Image ◽

Integrated Platform ◽

Hard And Brittle Materials ◽

Ultra Precision ◽

Cutting Experiments

Taper-cutting experiments are important means of exploring the nano-cutting mechanisms of hard and brittle materials. Under current cutting conditions, the brittle-ductile transition depth (BDTD) of a material can be obtained through a taper-cutting experiment. However, taper-cutting experiments mostly rely on ultra-precision machining tools, which have a low efficiency and high cost, and it is thus difficult to realize in situ measurements. For taper-cut surfaces, three-dimensional microscopy and two-dimensional image calculation methods are generally used to obtain the BDTDs of materials, which have a great degree of subjectivity, leading to low accuracy. In this paper, an integrated system-processing platform is designed and established in order to realize the processing, measurement, and evaluation of taper-cutting experiments on hard and brittle materials. A spectral confocal sensor is introduced to assist in the assembly and adjustment of the workpiece. This system can directly perform taper-cutting experiments rather than using ultra-precision machining tools, and a small white light interference sensor is integrated for in situ measurement of the three-dimensional topography of the cutting surface. A method for the calculation of BDTD is proposed in order to accurately obtain the BDTDs of materials based on three-dimensional data that are supplemented by two-dimensional images. The results show that the cutting effects of the integrated platform on taper cutting have a strong agreement with the effects of ultra-precision machining tools, thus proving the stability and reliability of the integrated platform. The two-dimensional image measurement results show that the proposed measurement method is accurate and feasible. Finally, microstructure arrays were fabricated on the integrated platform as a typical case of a high-precision application.

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An Investigation of the Cutting Strategy for the Machining of Polar Microstructures Used in Ultra-Precision Machining Optical Precision Measurement

Micromachines ◽

10.3390/mi12070755 ◽

2021 ◽

Vol 12 (7) ◽

pp. 755

Author(s):

Chen-Yang Zhao ◽

Chi-Fai Cheung ◽

Wen-Peng Fu

Keyword(s):

Precision Measurement ◽

Detection Algorithm ◽

Surface Generation ◽

Precision Machining ◽

Tool Geometry ◽

Depth Of Cut ◽

Machining Parameters ◽

Ultra Precision ◽

Transition Points ◽

Cutting Strategy

In this paper, an investigation of cutting strategy is presented for the optimization of machining parameters in the ultra-precision machining of polar microstructures, which are used for optical precision measurement. The critical machining parameters affecting the surface generation and surface quality in the machining of polar microstructures are studied. Hence, the critical ranges of machining parameters have been determined through a series of cutting simulations, as well as cutting experiments. First of all, the influence of field of view (FOV) is investigated. After that, theoretical modeling of polar microstructures is built to generate the simulated surface topography of polar microstructures. A feature point detection algorithm is built for image processing of polar microstructures. Hence, an experimental investigation of the influence of cutting tool geometry, depth of cut, and groove spacing of polar microstructures was conducted. There are transition points from which the patterns of surface generation of polar microstructures vary with the machining parameters. The optimization of machining parameters and determination of the optimized cutting strategy are undertaken in the ultra-precision machining of polar microstructures.

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