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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. Source


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. Source


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. Source


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. Source


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. Source

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