Papers by Author: Yi Lin

Abstract: Small amounts of Mn have been used in order to modify the microstructure and thus improve the properties of the alloys. The effect of Mn addition on structure and properties of cold rolled Al-Mg-Si-Cu alloy at different annealed temperatures is presented in this paper. Both recrystallization temperature and activation energy of recrystallization are obtained from the hardness-temperature curves. The results show that Mn can have an inhibitive effect on recrystallization. Within a certain concentration of Mn in the alloy (<0.7 wt.%) both the activation energy of recrystallization and recrystallization start temperature increase with the addition of Mn content. The activation energy of recrystallization of the alloy which contains 0 wt.% Mn, 0.3 wt.% Mn and 0.7 wt.% Mn are respectively 134.4 kJ·mol-1, 137.4 kJ·mol-1 and 140.1 kJ·mol-1 and the recrystallization start temperature increases from 190 to 230 as Mn content increases from 0 to 0.7 wt.%.

Abstract: Nano-porous anodic alumina oxide (AAO) templates are fabricated by anodizing method. The average diameter of nano-porous anodic alumina is 200 nm. The molded plastic thin film (Polycarbonate, PC) with nano-structure is fabricated by AAO as mold insert for nanoimprint. This research discusses the surface property of molded plastic thin film for different processing parameters (embossing temperature, embossing pressure, embossing time, de-molding temperature) on nanoimprint. The original contact angle of PC material without nano-structrue is about 78.2°. The contact angle of molded PC with nano-structrue is about 115.5°. The contact angle of molded plastic film (PC) with nano-structure is larger than that without nano-structure. The hydrophilic property of PC material has changed to hydrophobic property. A significant advantage of the fabrication process employed in this work is that it can create the good surface modification of plastic thin film.

Abstract: In this work, skeletons of micro aerial vehicle are fabricated by precision injection molding. The Taguchi method is adopted to identify the important factors that govern the shrinkage of MAV skeletons. The results indicate that the most significant factor in the shrinkage of a skeleton formed by precision injection molding is the mold temperature.

Abstract: The process of micro-powder blasting is the high speed gas flow which mixed the micro-particle and gas to impact the brittle substrate by the specialized nozzle. This paper combined various diameters Al2O3 eroding particle with a novel masking technique to fabricate the pattern channels in soda glass with a width to 2000 μm and depth down to 1631 μm. The masking technology for fabricating microchannel is consisted by the combination of two polymers: 1) the elastic and thermal-curable poly-(dimethyl siloxane) (PDMS) for its erosion resistance and 2) the brittle epoxy resin SU-8 for its photosensitivity. This paper discusses the processing procedure by the different processing parameters (micro-powder impact pressure, the distance between nozzle and substrate, micro-powder size, and micro-powder impact time) to find the optimal process. The results show that the micro-powder size is the most important factor for the depth of microchannel of microfluidic chip. The surface roughness of microchannel of microfluidic chip is nearly 5-6μm.

Abstract: This study demonstrates the replication property and surface roughness for metal micro-mold that combines the replica molding (REM) and electroforming techniques. The micro-mold firstly uses the silicon wafer to fabricate the master mold by UV-LIGA method, and then uses the sputtering method to sputter the Ni element as the seed layer on the surface of master mold. The electroforming method manufactures the Ni mold insert from the master mold with seed layer. Finally, this study uses the PDMS material to replicate the micro-feature from the Ni mold insert by replica molding. This study indicates the replication property and surface roughness of different micro-feature shapes and sizes (concave and convex) for Ni mold insert and molded PDMS.

Abstract: This study succeeds to replicate a micro-feature by ultrasonic nanoimprint. The conjunction effect of the pressure and the ultrasonic vibration enables flowing of plastic into a more precise micro-feature of the metal mold. The longitudinal wave generated by an ultrasonic system of the frequency 35KMz and output power 900W. The micro-feature of the Ni mold insert used in the experiment is a groove shape. The groove’s width is 49 µm and its depth is 25 µm. The PMMA, PC and PP are chosen with the replication materials. This study also discusses the replication properties of plastic film by different processing parameters (delay pressure, fusion pressure, embossing pressure, delay time, fusion time and embossing time).

Abstract: This research first indicates the melt front delay of wedge-shaped lightguiding plate of backlight module on micro injection molding. This research fabricated the patterns of mold insert of lightguiding plate by photo etching process. The micro-facture of lightguiding plate was manufactured by micro injection molding. The lightguiding plate of backlight module was used for the PMMA material. The single parameter method was used to discuss the flatness and replication properties for different processing parameters (mold temperature, melt temperature, packing pressure, packing time and injection pressure). The results show that there are melt front delays due to the slow injection velocity, the low temperature induced by the little effect of shear heating, the high viscosity, the large flow resistance and the slow flow velocity. The mold temperature is the most important factor for the flatness and the replication of micro-feature of liughtguiding plate. Lower mold temperature induces better flatness properties. The surface roughness of micro-facture of lightguiding plate is 8.8 nm on micro injection molding for this work.

Abstract: This work used micro dispensing technology to fabricate the master of microlens array, then uses electroforming technology to replication the Ni mold insert of microlens array and finally used micro hot embossing to replicate the plastic microlens array. This work used the Si10 resin by AutoStrade Company for dispensing material. The resin material was exposed to 80W halogen light. The resin will be hardened and become convex by surface tension effect on exposition. It can be used as the master of microlens array. This work sputtered a silver layer of 150 nm thick on the master for conducting electricity layer. The electroforming technology replicateed on the Ni mold insert from the master of microlens array. Finally, the micro hot embossing technology was used to replicate the molded microlens array. The molding experiment used PMMA and PC optical film. The experiment studied the influence of processing parameters of hot embossing by processing temperature, embossing pressure, embossing time and de-molding temperature. This work used the Taguchi’s Method to search the best processing parameter for molded microlens array. This work used the microscope, surface profiler and SEM to measure the surface profile of master, mold insert and molded microlens array. This work also used AFM to measure the surface roughness of master, mold insert and molded microlens array. In addition, this work measured the optical strength and the focal length to discuss optical characteristics of molded microlens array.

Abstract: This paper discusses the research of optimal process for lightguiding plate of backlight module of liquid crystal display. The PMMA material was used on lightguiding plate. This paper indicates that the different processing parameters (mold temperature, injection temperature, first period injection speed, second period injection speed, third period injection speed, packing pressure and packing time) are important for optimal research for lightguiding plate of backlight module. This paper introduces the extension engineering, simulated annealing and genetic algorithm on soft computing for optimal process and compares the results with experiment. The results show that the optimal process group is A1 B1C2 D3 E2 F2 G3 for extension engineering, simulated annealing, genetic algorithm or experiment. The mold temperature is the most important processing parameter of the flatness of lightguiding plate for soft computing and experiment. The calculation times for extension engineering, simulated annealing and genetic algorithm are less than experiment’s time.