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Surface Quality Improvement in machining an Aluminum Honeycomb by Ice Fixation

Chinese Journal of Mechanical Engineering 2020年第1期33卷 162-169页

作者： Yongqing Wang Yongquan Gan Haibo Liu Lingsheng Han Jinyu Wang Kuo Liu key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of TechnologyDalian 116024China

A honeycomb structure is widely used in sandwich structure components in aeronautics and astronautics;however,machining is required to reveal some of its *** honeycomb structures,deficiencies,such as burrs,edge subsiding,and cracking,can easily appear,owing to poor specific sti ness in the radial *** e ective fixation methods based on a filling principle have been applied by researchers,including approaches based on wax,polyethylene glycol,iron powder,and(especially)***,few studies have addressed the optimization of the cutting *** study focused on optimizing the cutting parameters to obtain a better surface roughness(calculated as a roughness average or Ra)and surface morphology in the machining of an aluminum alloy honeycomb by an ice fixation method.A Taguchi method and an analysis of variance were used to analyze the e ects and contributions of spindle speed,cutting depth,and feed *** optimal cutting parameters were determined using the signal-to-noise ratio combined with the surface *** F-value and P-value were calculated for the value of the Ra,according to a"smaller is better"***,the optimum cutting parameters for machining the aluminum honeycomb by ice fixation were found at different *** results of this study showed that the optimal parameters were a feed rate of 50 mm/min,cutting depth of 1.2 mm,and spindle speed of 4000 r/*** rate was the most significant factor for minimizing Ra and improving the surface morphology,followed by spindle *** cutting depth had little e ect on Ra and surface *** optimization,the value of Ra could reach 0.218μm,and no surface morphology deterioration was observed in the verified ***,this research proposes optimal parameters based on ice fixation for improving the surface quality.

关键词： Honeycomb Ice fixation Cryogenic milling Surface roughness Surface morphology Optimal parameters

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Simulation and prediction in laser bending of silicon sheet

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Transactions of nonferrous Metals Society of China 2011年第A1期21卷 188-193页

作者： WANG Xu-yue XU Wei-xing XU Wen-ji HU Ya-feng LIANG Yan-de WANG Lian-ji key laboratory for precision and non-traditional machining technology of the ministry of education Dalian University of Technology Dalian 116024 China

The laser bending of single-crystal silicon sheet （0.2 mm in thickness） was investigated with JK701 Nd：YAG laser. The models were developed to describe the beam characteristics of pulsed laser. In order to simulate the process of laser bending, the FEM software ANSYS was used to predict the heat temperature and stress-strain fields. The periodic transformation of temperature field and stress-strain distribution was analyzed during pulsed laser scanning silicon sheet. The results indicate that the mechanism of pulsed laser bending silicon is a hybrid mechanism in silicon bending, rather than a simple mechanism of TGM or BM. This work also gets silicon sheet bent after scanning 6 times with pulsed laser, and its bending angle is up to 6.5°. The simulation and prediction results reach well agreement with the verifying experiments.

关键词： laser bending silicon sheet pulsed laser simulation

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New Mathematical Method for the Determination of Cutter Runout Parameters in Flat-end Milling

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 947-952页

作者： GUO Qiang SUN Yuwen GUO Dongming ZHANG Chuantai key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of TechnologyDalian 116024China

The cutting force prediction is essential to optimize the process parameters of machining such as feed rate optimization, etc. Due to the significant influences of the runout effect on cutting force variation in milling process, it is necessary to incorporate the cutter runout parameters into the prediction model of cutting forces. However, the determination of cutter runout parameters is still a challenge task until now. In this paper, cutting process geometry models, such as uncut chip thickness and pitch angle, are established based on the true trajectory of the cutting edge considering the cutter runout effect. A new algorithm is then presented to compute the cutter runout parameters for flat-end mill utilizing the sampled data of cutting forces and derived process geometry parameters. Further, three-axis and five-axis milling experiments were conducted on a machining centre, and resulting cutting forces were sampled by a three-component dynamometer. After computing the corresponding cutter runout parameters, cutter forces are simulated embracing the cutter runout parameters obtained from the proposed algorithm. The predicted cutting forces show good agreements with the sampled data both in magnitude and shape, which validates the feasibility and effectivity of the proposed new algorithm of determining cutter runout parameters and the new way to accurately predict cutting forces. The proposed method for computing the cutter runout parameters provides the significant references for the cutting force prediction in the cutting process.

关键词： flat end milling cutter runout cutting force five-axis machining

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Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

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Journal of Materials Science & technology 2009年第3期25卷 319-324页

作者： Zhuji Jin Zewei Yuan Renke Kang Boxian Dong key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of Technology Dalian 116024 China

Dynamic friction polishing （DFP） is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost. By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere. However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality. In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying （MA） and spark plasma sintering （SPS）. The process of ball milling, composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed. The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix. The density of composite can be improved by mechanical alloying. The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sinterin8 in hardness, high-temperature oxidation resistance and wearability. These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.

关键词： CVD diamond film FeNiCr matrix-TiC composite Spark plasma sintering Mechanical alloying

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Remote-controlled flexible pose measurement system and method for a moving target in wind tunnel

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Chinese Journal of Aeronautics 2018年第1期31卷 89-98页

作者： Wei LIU Xin MA Ling CHEN Zhenyuan JIA Weixiao LIU Xiao LI Jiakun ZHANG Jiwen LU key laboratory for precision and non-traditional machining technology of the ministry of education Dalian University of Technology Dalian 116024 China

The measurement of position and attitude parameters for the isolated target from a highspeed aircraft is a great challenge in the field of wind tunnel simulation technology. This paper proposes a remote-controlled flexible pose measurement system in wind tunnel conditions for the separation of a target from an aircraft. The position and attitude parameters of a moving object are obtained by utilizing a single camera with a focal length and camera orientation that can be changed based on different measurement conditions. Using this proposed system and method, both the flexibility and efficiency of the pose measurement system can be enhanced in wind tunnel conditions to meet the measurement requirements of different objects and experiments, which is also useful for the development of an intelligent position and attitude measurement system. The position and the focal length of the camera also can be controlled remotely during measurements to enlarge both the vertical and horizontal measurement range of this system. Experiments are conducted in the laboratory to measure the position and attitude of moving objects with high flexibility and efficiency, and the measurement precision of the measurement system is also verified through experiments.

关键词： High-speed motion Machine vision Pose measurement Remote-controlled flexible Wind tunnel

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Redesigned Surface Based machining Strategy and Method in Peripheral Milling of Thin-walled Parts

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Chinese Journal of Mechanical Engineering 2010年第3期23卷 282-287页

作者： JIA Zhenyuan GUO Qiang SUN Yuwen GUO Dongming key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of Technology Dalian 116024 China

Currently, simultaneously ensuring the machining accuracy and efficiency of thin-walled structures especially high performance parts still remains a challenge. Existing compensating methods are mainly focusing on 3-aixs machining, which sometimes only take one given point as the compensative point at each given cutter location. This paper presents a redesigned surface based machining strategy for peripheral milling of thin-walled parts. Based on an improved cutting force/heat model and finite element method（FEM） simulation environment, a deflection error prediction model, which takes sequence of cutter contact lines as compensation targets, is established. And an iterative algorithm is presented to determine feasible cutter axis positions. The final redesigned surface is subsequently generated by skinning all discrete cutter axis vectors after compensating by using the proposed algorithm. The proposed machining strategy incorporates the thermo-mechanical coupled effect in deflection prediction, and is also validated with flank milling experiment by using five-axis machine tool. At the same time, the deformation error is detected by using three-coordinate measuring machine. Error prediction values and experimental results indicate that they have a good consistency and the proposed approach is able to significantly reduce the dimension error under the same machining conditions compared with conventional methods. The proposed machining strategy has potential in high-efficiency precision machining of thin-walled parts.

关键词： redesigned surface tool path part deflection error prediction finite element method

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Subsurface Damage in Scratch Testing of Potassium Dihydrogen Phosphate Crystal

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 15-20页

作者： WANG Ben WU Dongjiang GAO Hang KANG Renke GUO Dongming key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of Technology Dalian 116024 China

Potassium dihydrogen phosphate （KDP） is an important electro-optic crystal, often used for frequency conversion and Pockels cells in large aperture laser systems. To investigate the influence of anisotropy to the depth of subsurface damage and the profiles of cracks in subsurface of KDP crystal, an experimental study was made to obtain the form of subsurface damage produced by scratches on KDP crystal in [100], [120] and [110] crystal directions on （001） crystal plane. The results indicated that there were great differences between depth and crack shape in different directions. For many slip planes in KDP, the plastic deformation and cracks generated under pressure in the subsurface were complex. Fluctuations of subsurface damage depth at transition point were attributed to the deformation of the surface which consumed more energy when the surface deformation changed from the mixed region of brittle and plastic to the complete brittle region along the scratch. Also, the process of subsurface damage from shallow to deep, from dislocation to big crack in KDP crystal with the increase of radial force and etch pit on different crystal plane were obtained. Because crystallographic orientation and processing orientation was different, etching pits on （100） crystal plane were quadrilateral while on （110） plane and （120） plane were trapezoidal and triangular, respectively.

关键词： potassium dihydrogen phosphate (KDP) crystal scratch subsurface damage

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Effect of substrate curvature on thickness distribution of polydimethylsiloxane thin film in spin coating process

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Chinese Physics B 2018年第6期27卷 479-487页

作者： Ying Yan Ping Zhou Shang-Xiong Zhang Xiao-Guang Guo Dong-Ming Guo key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of Technology Dalian 116024 China

The polymer spin coating is critical in flexible electronic manufaction and micro-electro-mechanical system（MEMS）devices due to its simple operation, and uniformly coated layers. Some researchers focus on the effects of spin coating parameters such as wafer rotating speed, the viscosity of the coating liquid and solvent evaporation on final film *** this work, the influence of substrate curvature on film thickness distribution is considered. A new parameter which represents the edge bead effect ratio（re） is proposed to investigate the influence factor of edge bead effect. Several operation parameters including the curvature of the substrate and the wafer-spin speed are taken into account to study the effects on the film thickness uniformity and edge-bead ratio. The morphologies and film thickness values of the spin-coated PDMS films under various substrate curvatures and coating speeds are measured with laser confocal microscopy. According to the results, both the convex and concave substrate will help to reduce the edge-bead effect significantly and thin film with better surface morphology can be obtained at high spin speed. Additionally, the relationship between the edge-bead ratio and the thin film thickness is like parabolic curve instead of linear dependence. This work may contribute to the mass production of flexible electronic devices.

关键词： spin coating non-planar substrate film thickness distribution edge-bead effect

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Pre-Compensation for Continuous-Path Running Trajectory Error in High-Speed machining of Parts with Varied Curvature Features

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Chinese Journal of Mechanical Engineering 2017年第1期30卷 37-45页

作者： JIA Zhenyuan SONG Dening MA Jianwei GAO Yuanyuan key laboratory for precision and non-traditional machining technology of ministry of education Dalian University of TechnologyDalian 116024China

Parts with varied curvature features play increasingly critical roles in engineering, and are often machined under high-speed continuous-path running mode to ensure the machining efficiency. However, the continuous-path running trajectory error is significant during high-feed-speed machining, which seriously restricts the machining precision for such parts with varied curvature features. In order to reduce the continuous-path running trajectory error without sacrificing the machining efficiency, a pre-compensation method for the trajectory error is proposed. Based on the formation mechanism of the continuous-path running trajectory error analyzed, this error is estimated in advance by approximating the desired toolpath with spline curves. Then, an iterative error pre-compensation method is presented. By machining with the regenerated toolpath after pre-compensation instead of the uncompensated toolpath, the continuous-path running trajectory error can be effectively decreased without the reduction of the feed speed. To demonstrate the feasibility of the proposed pre-compensation method, a heart curve toolpath that possesses varied curvature features is employed. Experimental results indicate that compared with the uncompensated processing trajectory, the maximum and average machining errors for the pre-compensated processing trajectory are reduced by 67.19% and 82.30%, respectively. An easy to implement solution for high efficiency and high precision machining of the parts with varied curvature features is provided.

关键词： trajectory error dynamic error pre-compensation continuous-path running high-feed-speed machining,parts with varied curvature features

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Damage mechanisms during lapping and mechanical polishing CdZnTe wafers

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Rare Metals 2010年第3期29卷 276-279页

作者： LI Yan,KANG Renke,GAO Hang,and WU Dongjiang key laboratory for precision and non-traditional machining technology (ministry of education),Dalian University of technology,Dalian 116024,China key laboratory for precision and non-traditional machining technology (ministry of education) Dalian University of Technology Dalian China

CdZnTe wafers were machined by lapping and mechanical polishing processes,and their surface and subsurface damages were *** surface damages are mainly induced by three-body abrasive wear and embedded abrasive wear during lapping process.A new damage type,which is induced by the indentation of embedded abrasives,is found in the *** a floss pad is used to replace the lapping plate during machining,the surface damage is mainly induced by two-body abrasive and three-body abrasive wear,and the effect of embedded abrasives on the surface is greatly ***,this new damage type nearly disappears on the subsurface.

关键词： lapping mechanical polishing wafers surface subsurface abrasive

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