Key Laboratory of Special Purpose Equipment and Advanced Processing Technology

Hangzhou, China

Key Laboratory of Special Purpose Equipment and Advanced Processing Technology

Hangzhou, China
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Lv B.,Hunan University | Wu Z.,Hunan University | Yuan J.,Hunan University | Fan H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Advanced Materials Research | Year: 2011

The dressing principle of a newly developed metal bonded superabrasive tool named porous self-generation superabrasive tool (PSST) is introduced. It is found that the 'soluble' filler added in the bond material can be dissolved by certain solution, and porous structure can be formed on the highly compacted surface layer of the metal-bonded superabrasive tool. The dressing process of PSST are investigated by a series of lapping experiments. Surface topography of PSST during lapping process is observed. It is found that the porous structure can be maintained on the PSST surface layer during the lapping process. There is little jam happened on the PSST surface. The generated porous binder on PSST surface layer is more susceptible to bond fracture, which is benefit to the self-sharpening of the metal bonded superabrasive tool. © (2011) Trans Tech Publications, Switzerland.


Lu C.D.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wang J.J.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wen D.H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Advanced Materials Research | Year: 2011

Proton exchange membrane fuel cell (PEMFC) has high power density and energy conversion efficiency. Bipolar plate is one of the key components of the proton exchange membrane fuel cell, not only affects the performance of the battery, but also affects the cost of the battery, which is become a bottlenecks. This paper introduces several common forms of the bipolar plate flow channel of the PEMFC, analyzes their advantages and disadvantages, and then some new type of flow channel type comes up after improvements on this basis, so the future development trend of fuel cells summed up is combined with bionics or using a complex flow field. An overview of the commonly used material and processing of the bipolar plate, respectively, graphite sheet, sheet metal and composite bipolar plates.


Wen D.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Qi H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Ma L.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Lu C.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Li G.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Precision Engineering | Year: 2016

The fixed abrasive lapping process is presented to investigate its ability and accuracy in machining of interdigitated micro-channels on bipolar plates that are used in the proton exchange membrane fuel cell. A kinematical equation to describing the relative movement between the fixed abrasive lapping plate and workpiece is developed and used to numerically simulate the trajectories of a single diamond abrasive and fixed diamond abrasives with 17 different arraying forms, respectively. It is shown that the lapping trajectory can be superposed periodically when the rotation ratio is a rational number. By assessing the uniformity of lapping trajectories and opening ratio of the bipolar plate the optimized rotation ratio is obtained which is 1:1, and the best arraying form of the fixed diamond abrasives on the lapping plate has been obtained as well that is the arraying form of C4. Then, a set of fixed abrasive lapping tests were conducted to explore its ability in machining of interdigitated micro-channels on bipolar plates. It is found that larger material removal rate can be achieved by employing bigger lapping pressure and higher rotation speed for both copper and stainless steel samples considered in this study. The maximum cell power density is found to be about 165 mW cm-2 by testing the performance of a single micro fuel cell with a bipolar plate characterized by interdigitated micro-channels that shows a good cell performance. © 2015 Elsevier Inc. All rights reserved.


Zhu F.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Li S.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Applied Mechanics and Materials | Year: 2012

Structure static testing is an important means to study the static characteristic of complex engineering structure. Electrohydraulic stactic loading system is the singnificant equipment of the testing. With its function of transfering low-power electrical singal to large-power hydraulic output quickly and precisely, the servo valve plays a key role in an electrohydraulic servo control system and dominates to a large extent the performance of the whole control system. Conventional electrohydraulic servo or proportional control is subject to the nonlinearites of their electro-mechanical interface, such as hysteresis, saturation and finite resolution. In this paper, a direct actuated digital servo valve was applied in electrohydraulic static loading system. It can be driven directly by computer needn't D/A and has the advantages of simple structure, high tolerance to contamination and high reliability. Practical load-experiment results show that the static loading system with a direct actuated digital servo valve can work steadily and reliably and possess high accuracy and fast response. © (2012) Trans Tech Publications, Switzerland.


Guan J.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Xu X.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Li G.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Peng W.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Applied Surface Science | Year: 2014

The inclusion complex of β-cyclodextrin (β-CD) and dialkyl pentasulfide (DPS), in which DPS was incorporated into β-CD cavities, was prepared by a co-precipitation method. The tribological properties of the complex used as lubricant additive in PEG 600 aqueous solution were investigated by a four-ball tester. The complex exhibited better tribological properties than β-CD under different loads, and also showed better anti-friction performance than DPS in the latter half of the test duration. The tribological action mechanism of the complex on a steel surface was studied according to the X-ray photoelectron spectroscopy (XPS) analyses. The β-CD molecules of the complexes were decomposed into various molecular fragments and the DPS molecules were released under the friction condition. It revealed that thiolate and ferrous sulfide (FeS) films formed by DPS played a major role, and iron alkoxide and carbon deposition films formed by the friction fragments of β-CD mainly exhibited anti-friction property on FeS-to-FeS interface. The interactions among different films led to the formation of a mixed boundary lubrication film. © 2013 Elsevier B.V.


Tang Y.J.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wang Y.Y.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Ji S.M.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Zhang X.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wen D.H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Advanced Materials Research | Year: 2011

Cutting forces generated in broaching have a direct influence on the generation of heat, tool wear or failure, quality of machined surface and accuracy of the work piece. In this paper not only a cutting forces test scheme has been proposed but also a cutting forces measurement equipment has been designed with PCB 740B02 dynamical strain sensor and LMS SCADA III test system, respectively. Dynamical strain sensor was pasted on the cylinder type sensitive elements with which table and work piece was connected. Experimental investigation on the dynamic cutting forces in the broaching direction of a hydraulic broaching machine had been carried out. Cutting forces measurement tests on Q235 steel work piece material during broaching had been performed. Broaching in a variety of velocities, namely, 3.3m/min, 5m/min and 8m/min and in a variety of cutting depth, namely, 0.03mm, 0.04mm, 0.05mm and 0.07mm, were investigated. Output signal was analyzed both in time and frequency domains and the key characteristics of the cutting forces signal was obtained. Correlation between the frequency of broaching forces and the broaching velocity was also studied.


Pan G.Q.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wang Z.W.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wen D.H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Advanced Materials Research | Year: 2011

This paper give some literatures for the technology of fluid polishing. Methods of fluid polishing using for optics curved surface, ultra-smooth plane and inner surface of non-circular curved surface. Each method is explained by above classifications, and some domestic cases which can produce ultra-smooth surface in different conditions, parts and technical parameters is listed and evaluated.


Yuan J.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Yao W.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Zhao P.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Lyu B.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | And 2 more authors.
International Journal of Machine Tools and Manufacture | Year: 2015

The both-sides lapping process in planetary motion type is proposed in this paper to lap and polish the cylindrical surface of bearing roller. The rolling speed of roller is the key kinematical parameter that affects the generation of cylindrical surface of roller. Through analysis of friction forces and pure rolling motion, it was discovered that the rolling speed of roller only depends on the rotation speed of lower plate rather than upper plate. Based on the above result, the geometry and kinematics of workpiece in this method is described, and the functions are proved valid by an experiment in which the rolling speed of roller is observed in video. By theoretical tests under different speed conditions, it is indicated that the roller's rolling speed varies with respect to time along a nonstandard cosine curve with an offset, its amplitude depends on the speeds of lower plate rotation and carrier circulation, and its offset depends on the speeds of lower plate rotation and carrier rotation. Based on geometry and kinematics, the trajectories on the cylindrical surface of roller and on the flat surface of plate are both described and simulated. The standard deviation and the range of path curve length distribution density are applied to numerically evaluate and analyze the trajectory distribution. The effect of speed parameters on the trajectory distribution, and the generation of trajectory with respect to time are investigated. © 2015 Elsevier Ltd All rights reserved.


Wang Z.W.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Pan G.Q.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wen D.H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Advanced Materials Research | Year: 2011

This keynote paper aims at introducing applications of ultrasonic radiation force in industry. The chosen focus is to understand how to use it. Since the phenomenon of acoustic levitation can reflect the exciting of ultrasonic radiation force directly. The paper starts with an analysis on the tungsten ball floating on a sound field and ultrasonic micro-manipulation study in micro Electronic Mechanical System (MEMS). And ultrasound has been successfully used to degrade wastewater as its cavitation. At the same time, different kinds of micro-ultrasonic machining were used to show how exciting machining and ultrasonic radiation combined. A view from the authors and the final Conclusions show future applications of ultrasonic radiation force.


Zhang J.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wang W.F.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology | Wen D.H.,Key Laboratory of Special Purpose Equipment and Advanced Processing Technology
Advanced Materials Research | Year: 2011

This paper reviews three methods used to evaluate the uniformity in the lapping process. The first one evaluates the uniformity in lapping process according to studying the uniformity of lapping trajectory. The second one, compared with the measurement pattern based on polar coordinate, explains the advantages of Cartesian -based coordinate pattern in evaluating the lapping uniformity. The last one develops a model to calculate material removal in the lapping process and indicates the uniformity by calculating the material removal. These methods evaluate the uniformity in lapping process from different views, respectively, but each method still has various drawbacks. Therefore, further researches must be carried out to improve the system used to evaluate the uniformity in the lapping process.

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