Applied Mechanics and Materials Vol. 289

Abstract: Micro and desktop factories are small-size production systems suitable for the manufacture of small products with micro and/or macro size features. The development originates in Japan, where small machines were developed in order to save resources when producing small products. In the late 1990’s, the research spread around the world, and since then multiple miniaturized production systems have been developed. However, the level of commercialization and industrial adoption is still relatively low and the breakthrough remains unseen. This paper discusses the potential application areas of micro- and desktop factory solutions. The research has been carried out as a mixed-method research combining extensive literature survey and 18 semi-structured interviews in Europe. The interviewees are both from academia and industry, including equipment and component providers, as well as users and potential users.

Abstract: Needle is one of the most common features in medical devices. A better understanding of needle tip geometry can lead to the creation of an optimized needle tip geometry which would greatly benefit the procedure of biopsy or insertion guidance. This study reviews the recent researches on needle cutting edge with high inclination angle, and applications in needle core biopsy and insertion guidance. The mathematical models of the inclination and rake angles for the needle with lancet point and enhanced cutting edge needles are developed. To improve the biopsy length, a novel approach to use the enhanced cutting edge needle to acquire the tissue sample is studied and the concept is experimentally validated. To reduce needle deflection and increase insertion accuracy, the effects of grid constraints, needle material, and insertion speed are analyzed. The knowledge gained from this study can be used to better understand needle tissue cutting mechanics and integrate these technologies for more efficient needle biopsy and accurate insertion guidance procedures.

Abstract: Among various kinds of carbon materials, two types of amorphous carbon were employed as a mold-die material for micro-forming. Diamond like carbon (DLC) has sufficient strength and toughness as a protective coating onto the steel and WC (Co) substrates. Glassy carbon is a solid material which also has high strength even at the elevated temperature under inert gas atmosphere. These two materials are selected to fabricate the micro-textured mold-die as a mother tool to duplicate this micro-textured pattern onto the metallic and polymer sheets via table-top CNC micro-forming systems. High density oxygen-plasma etching and pico-second laser machining were developed to make micro-texturing onto the above two mold-die materials. In the former, micro-groove and micro-grid patterns were formed on the DLC coating; table-top CNC stamping system with CNC-feeder and cropper was used to duplicate these patterns onto the aluminum sheets in dry and at the room temperature. In the latter, micro-wedge patterns were imprinted onto the glassy carbon substrate; table-top CNC mold-stamping system with heating equipment was utilized for duplication of these patterns onto thermoplastic polymer sheets above the glass transition temperature. Formation of micro-textures onto these amorphous carbon materials provides us a new tool to fabricate the micro-patterned parts and devices in mass production via cold and hot stamping processes.

Abstract: In this work, we demonstrate a simple yet convenient centrifugal microfluidics, or lab-on-a-disc (LOAD) platform for bead-based immunoassays. The disc contains a network of passive valves for sample manipulation and a bead-aggregating barrier structure to instead of commonly used immobilization method. The narrow-channel structure not only provides a geometric barrier for retaining the beads, but also significantly increased fluidic resistance which results in lower flow rate and longer reaction time for each reagent in the reaction chamber. Centrifuge-forced beads densification in the small junction area and signal concentrating allows high signal sensing capability. The acceleration speed is optimized for largest signal-to-noise ratio. The device uses different rotation speed to trigger a cascade of flow events. The integrated platform contains all the necessary functional elements for conducting one-step parallel assays through a sequential protocol. For our test device, the total time required to complete an immunoassay experiment is typically under 6 minutes. Through this work we have also shown that the use of a geometric barrier for the aggregation of signaling beads is an effective approach for the enhancement of optical signals in common immunoassays. This flexible design is suitable for a broad range of bead-based immunoassays with low-cost and high-speed operation.

Abstract: In this paper, Nanostructured Titania (NST) was fabricated by aging titanium film in hydrogen peroxide solution. NST was analyzed and characterized using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), nano-indentation method and the BET method. Results showed that NST was porous TiO2 with pore diameter of 90-133 nm, hardness of 1.35Gpa, and specific surface area of 37.26 m2/g. Gas sensors using NST film as sensitive material were presented in this paper too. Electrodes were deposited upon NST patterns to create electrical connections. Gas sensors with a simple package were successfully fabricated.

Abstract: we propose a micro varied-line-spacing (VLS) grating-lens hybrid component that integrates the collimation, dispersion and focus functions for use in a miniature spectrometer. We adopt the principle of least wave change to design and optimize the VLS grating pattern on the spherical lens surface, and then build a model in ZEMAX to simulate the spectral resolution performance. The best spectral resolution turns out to be 1nm at the center wavelength of the target wavelength range. The resolution across the wavelength range from 450nm to 650nm is better than 4nm.

Abstract: Multi-channel optical filter can separate the target light so that it can be integrated in the multi-spectral imaging system for collecting the images in different spectrum. However, conventional multi-channel optical filter cannot work in visible band and near-infrared band simultaneously. This paper will present a novel method for fabricating the multi-channel filter which can work for the two bands. The method combines pigment-based colorant photoresist microlithography with traditional multi-film vacuum deposition technologies so that the filter has a high integrated level. The results of test show that the filter can be used for the wavelength range from 400 to1200 nm. Because of its wide working wavelength range, this optical filter has a great prospect of being applied in the fields of day and night surveillance, medical imaging, and so on.

Abstract: The dynamic analysis and structural parameters optimization approach based on ADAMS for a parallel platform is presented in this paper. Firstly the parameterized modeling of the parallel platform is performed, which is composed of up and down platform, two linear motors and one support beam. And then the impact of the parameters on the performance of the platform is studied. After that the parallel platform is optimized via the optimization module of the ADAMS. Eventually the conclusions are obtained, which provide the guidance for the mechanical and control design of the parallel platform.

Abstract: In this paper, in order to reduce the external radiation of food refrigeration compressors noise, the main noise frequency analysis based on the theoretical calculation and practical experiment is carried out and the acoustic enclosure design is conducted. Conventional sound-absorbing material adopts rock wool and glass wool which have poor environmental protection. In the design process the environmental friendly melamine cotton is chosen as the sound-absorbing material that has not ever been massively adopted. Whats more, with a consideration of ventilation and heat dissipation, acoustic enclosure interior is designed with muffler air duct and the low-speed and low-noise fan. Therefore, both the normal operation of the compressor and the sound insulation of the acoustic enclosure are ensured in this way. Then with the sound level meter the noise A-weighted SPLs of the compressor with and without the enclosure are measured and are compared with each other. The results show that after covering the acoustic enclosure the compressors noise is less than 60 dB, which meets the design requirements of noise control. Therefore, it is easy to conclude that the sound insulation of the acoustic enclosure reaches the design standards and the acoustic enclosure design is feasible.