Tianjin MicroNano Manufacturing Technology Co.

Tianjin, China

Tianjin MicroNano Manufacturing Technology Co.

Tianjin, China

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Zhang Q.,Tianjin University | Fang F.,Tianjin University | Fang F.,Tianjin MicroNano Manufacturing Technology Co. | Xu Z.,Tianjin University | And 3 more authors.
International Journal of Nanomanufacturing | Year: 2014

A novel method for a novel type of surface enhanced Raman scattering (SERS) active substrate is proposed with high enhancement and strong sensitivity advantages. It is based on nanoscale Au film nanocracks coated on polydimmethyl siloxane (PDMS) substrate which forms gold/ polydimethylsiloxane (Au/PDMS) nanocomposites. The width of the coated nanocracks ranges from 10 nm to 45 nm by self-assembled. It is concluded that the ratio of main agent to firming agent of PDMS at 9:1 is optimum value for SERS due to its complicate texture of cracks. An enhancement factor (EF) as high as 3.14*108 is achieved for 4-Mercaptobenzoic acid molecules adsorbed on the Au/PDMS nanocomposite substrates.Copyright © 2014 Inderscience Enterprises Ltd.


Wang Y.,Tianjin University | Gong H.,Tianjin University | Gong H.,Tianjin Micro Nano Manufacturing Technology Co. | Fang F.Z.,Tianjin University | And 2 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2015

Compared with the conventional machining (CM), rotary ultrasonic machining (RUM) is generally believed to have many better cutting features, such as low cutting force, high material removal rate, and long tool life. But this paper presents an interesting observation on ultrasonic vibration-assisted drilling and milling with spiral cutting tools (SCT). Due to the special spiral structure of tools, ultrasonic vibration at the end of tool has more complex characters which may generate a negative effect on machining. In this paper, several RUM experiments were conducted, and we found that the cutting force is not always reduced when using SCT. Through the finite element method (FEM), we found that two kinds of vibrational direction are shown at the end of the SCT when the vibrational frequency changes. One is along the first and third quadrants, and the other is along the second and fourth quadrants. Since the vibrational direction affects the actual cutting angle and interference may occur, this change will greatly affect the cutting force and the surface quality. Therefore, a kinematics model of the vibration on the cutting edge will be proposed to understand the cutting mechanism of RUM deeply. © 2015 Springer-Verlag London


Gong H.,Tianjin University | Gong H.,Tianjin MicroNano Manufacturing Technology Co. | Wang N.,Civil Aviation University of China
CAD Computer Aided Design | Year: 2011

A new tool path generation method of flank milling considering constraints is proposed for ball-end cutters in this paper. It will not only reduce the machining error range but also meet the following two constraints: (a) The ball end of the milling tool is tangential to the constraint surface; (b) There is no overcut and the minimum error is zero, which is called nonnegative-error constraint. The two constraints are very useful in some situations of engineering applications, such as flank milling impeller blades. Based on the proposed method, two types of cutter will be used to generate tool paths for the same designed surface and constraint surface. The effectiveness and accuracy of the proposed method will be finally proved with some examples. © 2011 Elsevier Ltd. All rights reserved.


Gong H.,Tianjin University | Gong H.,Tianjin MicroNano Manufacturing Technology Co. | Fang F.Z.,Tianjin University | Fang F.Z.,Tianjin MicroNano Manufacturing Technology Co. | And 3 more authors.
CAD Computer Aided Design | Year: 2010

The Basic Curvature Equations of Locally Tool Positioning (BCELTP) are an accurate description of the relationships between the second order approximations of the cutter surface, the tool envelope surface and the designed surface, which was proposed in our previous paper [Gong Hu, Cao Li-Xin, Liu Jian. Second order approximation of tool envelope surface for 5-axis machining with single point contact. Computer-Aided Design 2008;40:604-15]. Based on them, for a given tool path with single cutter contact point, a new local optimization method of tool positions is presented to maximize the machining strip width by minimizing the relative normal curvature between the tool envelope surface and the designed surface. Since the BCELTP are accurate analytical expressions, the proposed optimization method of tool positions is accurate and effective in computation. Furthermore, another new optimization method of tool positions based on a dual-parameter envelope is subsequently proposed. The most interesting point is that it will result in the same results as the method based on the BCELTP. It also proves the correctness of the method based on the BCELTP from a different angle. Finally, several examples are given to prove its effectiveness and accuracy. © 2010 Elsevier Ltd. All rights reserved.


Gao T.,Tianjin University | Xu Z.,Tianjin University | Xu Z.,Tianjin MicroNano Manufacturing Technology Co. | Fang F.,Tianjin University | And 4 more authors.
Nanoscale Research Letters | Year: 2012

A novel method with high flexibility and efficiency for developing SERS substrates is proposed by patterning nanostructures on Si substrates using focused ion beam direct writing (FIBDW) technology following with precise thermal evaporation of gold film on the substrate. The effect of SERS on the substrate was systematically investigated by optimizing the processing parameters and the gold film thickness. The results proved that small dwell time could improve the machining accuracy and obtain smaller nanogap. The Ramanenhanced performance of the substrate was investigated with 10-6 mol/L Rhodamine 6 G solution. It was indicated that the elliptic nanostructures with 15-nm spacing on Si substrates, coated with approximately 15-nm thick gold film, have exhibited a high-enhanced performance, but dramatic performance degradation was found as the gold film thickness further increased, which most probably resulted from changes of the nanostructures' morphology such as elliptical tip and spacing. To avoid the morphological changes effectively after depositing gold film, optimization design of the nanostructures for FIBDW on Si substrates was proposed. Besides, a similar phenomenon was found when the gold film was less than 15 nm because there was little gold remaining on the substrate. The method proposed in this paper shows a great potential for the higher performance SERS substrates development, which can further reduce the spacing between hot spots. © 2012 Gao et al.


Xu Z.W.,Tianjin University | Xu Z.W.,Tianjin MicroNano Manufacturing Technology Co. | Fang F.Z.,Tianjin University | Fang F.Z.,Tianjin MicroNano Manufacturing Technology Co. | And 6 more authors.
Optics Express | Year: 2010

A novel method is proposed to fabricate micro Diffractive Optical Elements (DOE) using micro cutting tools shaped with focused ion beam (FIB) milling. Micro tools with nanometric cutting edges and complicated shapes are fabricated by controlling the tool facet's orientation relative to the FIB. The tool edge radius of less than 30 nm is achieved for the nano removal of the work materials. Semi-circular micro tools and DOE-shaped micro tools are developed to fabricate micro-DOE and sinusoidal modulation templates. Experiments show that the proposed method can be a high efficient way in fabricating micro-DOE with nanoscale surface finishes. © 2010 Optical Society of America.


Fang F.Z.,Tianjin University | Fang F.Z.,Tianjin MicroNano Manufacturing Technology Co. | Xu Z.W.,Tianjin University | Xu Z.W.,Tianjin MicroNano Manufacturing Technology Co. | And 4 more authors.
CIRP Annals - Manufacturing Technology | Year: 2010

A novel nano-photomask fabrication method using focused ion beam direct writing (FIBDW) is proposed to normalize the dwell time of each pixel of the ion beam location with respect to the contrast of designed bitmaps. The removal mechanism is studied to develop the fabrication process. It has been confirmed that beam dwell time, astigmation and overlap are the most effective parameters for achieving the features in nanoscale. An approach for dot array milling is proposed also for inspecting and correcting the beam astigmatism. Photomasks with line width of 32 nm are employed for the purpose of successful application of this novel method in this study. © 2010 CIRP.


Gong H.,Tianjin University | Gong H.,Tianjin MicroNano Manufacturing Technology Co. | Fang F.Z.,Tianjin University | Fang F.Z.,Tianjin MicroNano Manufacturing Technology Co. | Hu X.T.,Tianjin University
International Journal of Advanced Manufacturing Technology | Year: 2012

An accurate spiral tool path generation method of ultraprecision three-axis turning free form surface is proposed based on symbolic computation in this paper. Many analytic optical free form surfaces often need to be machined to submicron in form error, such as optical nonaxisymmetric aspheric surfaces, but current mainstream CAM systems usually use nonuniform rational basis spline (NURBS) to describe the designed surface and generate tool path. If we want to use these systems, the analytical optical surfaces must be approximated using NURBS surfaces, but it will introduce approximation error and may be difficult to achieve the approximation error less than submicron. More importantly, there is no effective tool path generation method for the special three-axis turning machine tool in current mainstream CAM systems. In this context, we propose to calculate the tool path directly from these analytic surfaces by using symbolic math. The proposed method can be used to generate accurate spiral tool paths for zero/negative/positive rake angle in a unified way. Finally, several examples are given to prove its effectiveness. © 2011 Springer-Verlag London Limited.


Gong H.,Tianjin University | Gong H.,Tianjin MicroNano Manufacturing Technology Co. | Fang F.Z.,Tianjin University | Fang F.Z.,Tianjin MicroNano Manufacturing Technology Co. | Hu X.T.,Tianjin University
International Journal of Machine Tools and Manufacture | Year: 2010

Experiments are conducted to study the mechanism of side milling in rotary ultrasonic machining (RUM). The study shows that RUM has less tool wear than grinding at the lateral direction of the cutter under the same conditions. The kinematics of diamond grits is employed for the theoretical analysis. In addition, by using slim diamond cutters, two different machining strategies are used to side mill a microstructure and grooves on a semi-sphere. An improvement strategy of material removal rate (MRR) is also discussed based on the experimental study. © 2009 Elsevier Ltd. All rights reserved.


Zhao C.-Y.,Tianjin University | Gong H.,Tianjin University | Gong H.,Tianjin MicroNano Manufacturing Technology Co. | Fang F.Z.,Tianjin University | And 2 more authors.
Machining Science and Technology | Year: 2013

A comprehensive experimental study on the cutting force differences between rotary ultrasonic machining (RUM) and conventional diamond side grinding, drilling and face grinding is conducted on K9 glass. By analyzing the experimental results and the kinematics of diamond grits, it can be seen that the reasons for the cutting force differences between with and without ultrasonic vibration are not same for the three machining processes. The cutting force difference of conventional diamond side grinding and RUM can be explained by analyzing the trajectory of diamond grits, while the cutting force difference of conventional diamond drilling and RUM is mostly dependent upon the difficulty level of removing chips. As a transitive form, the cutting force difference between conventional diamond face grinding and RUM is affected by both the diamond grits' trajectory and the difficulty level for removing chips. In addition, it is also noticed that different cutting tools have different reduction percentages of cutting forces in RUM compared with conventional diamond grinding. The findings are helpful for researchers to have a further understanding in RUM. © 2013 Copyright Taylor and Francis Group, LLC.

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