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This paper analyzes the reason why the polymer is melted on a non-forming surface during ultrasonic embossing and proposes a method to inhibit the polymer melting.On the basis of the heating mechanism of ultrasonic,it points out that the polymer melting phenomenon on non-forming surface is resulted by the friction in a horn-substrate interface.Then,it proposed the method"two interfaces of different friction coefficients"to inhibit the polymer melting and implemented the method by coatings surface protection films on the non-forming surface.To optimize the protection films,and the influences of the four coating film conditions on the softening time are examined through Taguchi method.The results show that the Sekisui#622E-50 film shortens the softening time by 3.4sandthe Sekisui#622WB film reduces the softening time error by 0.64 s.It demonstrates that surface protection films coated can avoid polymer melting on the non-forming surface,and improve the process replication ability and the process stability in ultrasonic embossing.

As nonlinear technology allows piezoelectric energy harvesting to obtain a wider vibration frequency and a higher output voltage, this paper proposed a piezoelectric energy harvester based on nonlinear vibration. The oscillation equation of the piezoelectric energy harvester was obtained based on testing Duffing mode and its vibration characteristics were simulated. With the various sinusoidal excitation frequencies and different magnet spacings, the opened output voltage was measured. The results show that when the excitation acceleration is 20 m/s2, the output voltage from the energy harvester has been improved to 208 V from 131 V, its maximum output power is 43.264 mV, and the resonance frequency region can range up to 18 Hz. The Duffing model structure can change the resonant frequency of the nonlinear piezoelectric energy harvester in small scope, and can increase the output voltage.

To reduce the system dividing error of a grinding machine in gear grinding and to improve the machining accuracy of gears,the relationship among the dividing error of grinding machine,gear eccentricity installation,and the pitch deviation was analyzed,and the calculation method for dividing errors of the gear was obtained.By adjusting the grinding machine according to the calculated dividing error,the dividing error of grinding machine and the cumulative pitch deviation of the gear were decreased and the manufacturing accuracy was enhanced.The method was verified by taking the flat-faced wheel grinding machine Y7125 as an example.Firstly,a mathematic model on gear eccentricity installation and profile deviation was established to figured out the amplitude and phase angles of gear eccentricity installation.Then,based on the relationship among gear eccentricity installation,the dividing error of grinding machine and the pitch error,the value of dividing error was obtained.Finally,the indexing plate of grinding machine was adjusted and calibrated according to the computed dividing error.The experiment demonstrates that the dividing error has been reduced from 17.7 μm to 3.3 μm,and the cumulative pitch deviation of the machined gear is lowered from 46.9 μm to 11.5 μm.Furthermore,the accuracy of pitch is up to grade three.The results prove that this method can be used to reduce the dividing error of grinding machine effectively,so as to reduce the cumulative pitch deviation.

To improve the bonding efficiency of microfluidic chips,an in-mold bonding method is researched by taking a Polymethyl Methacrylate(PMMA) microfluidic chip as an research object and a micro injection machine as a working platform.Clamping forces and bonding temperatures are provided by the micro injection machine and a mold temperature machine.Isopropanol is selected as assistant solvent to reduce the bonding temperature and bonding pressure with its solubility.At 30 ℃ to 70 ℃,a microscope and a step profiler are used to analyze the influence of assistant solvent on surface morphologies and micro channel structures of chips at different temperatures.An in-mold bonding experiment is operated with the assistant solvent,then the electric universal testing machine is utilized to measure the bonding strength and to optimize the process parameters.Experimental results illustrate that the influence of isopropanol on bonding quality is related with the bonding temperature and bonding period.The surfaces of chips chap and the micro grooves become deformed or block at higher temperatures.The surface quality and morphologies of micro grooves are correspondingly improved when the bonding temperature is 35 ℃,the bonding time is 5 min,and the bonding strength is no less than 2.64 MPa.

The slippage between discs and rail is one of important factors for the measurement accuracy of an involute.However,control of frictions effectively can modify the slippage of discs.In the paper,frictions between discs and rail are analyzed respectively when a cord and a belt are used to drive the discs to roll.According to the analysis and experiment,it shows that if measuring forces are 0.7 N and 0.2 N and the base discs is drived by the cord and belt,frictions are 0.02 N and 0.07 N respectively,for the base disc clockwise rolled;where the effect of the slippages of based discs on the involute measurement can be ignored.Moreover,the slippage can also be reduced by increasing the weight of base disc groups,and measurement difference of involute is 0.06 μm when the rolling directions of the base discs are different.

To establish the scientific principles and technical frameworks of the ultra-precision grinding technology,the research work was performed on the processing principles and methods of the ultra-precision gear-grinding to develop the ultra-precision master gears with class 1(ISO 1328-1:1995).Firstly,according to the optimal forming of an involute and the easy refinement and high structural rigidity of the machine,the gear grinder with flat-faced wheel Y7125 was chosen as the object machine tool.Then the ultra-precision gear-grinding processing was discussed and studied from the aspects of gear blank processing and datum renovation,optimal adjustment of grinder parameters and scientific gear-grinding operation.Finally,the medium module(m2 and m4) ultra-precision master gears with class 1 were developed by a scientific gear-grinding experiment.The research on ultra-precision gear-grinding processing plays a guiding role in the overall improvement of gear manufacturing technology in China.