Papers by Keyword: Micro Gear

Abstract: In recent years there has been a considerable interest in microsystems, named as MEMS (Micro Electromechanical Systems). Its continuing expansion is expected, derived from the trend towards miniaturization of components and the increasing applications for these micro devices. To overcome this, the technology to produce these products known as microsystem technology (MST), has been improving in order to allow the manufacturing of this type of parts becoming of growing importance over the past years. Micro gears are commonly used in electronics industry where the miniaturization process follows a constant evolution with multiple use advantages despite their small size. In this work the study and analysis of the existing verification techniques for micro gears together with the definition of a double flank rolling test focused on these gears is presented.

Abstract: The development of microsystems and related products has caused an upsurge in the mass production of micro components. In the paper, fabrication of zirconia micro gears of 700μm, 800μm, 900μm based on water-soluble binder were investigated. The water-soluble binder system consists of 30%PEG-4000+10%SA+30%PVB+30%EVA components. Experimental results show that zirconia micro gears are successfully fabricated using the in-house feedstock. And the decrease of the molecular weight of water-soluble component is beneficial to the quality of the molded part.

Abstract: Micro gears with different dimension were fabricated by micro metal injection molding and sintering behavior of the micro gear was investigated. For this, ultraprecision micro molds were prepared by micro electroforming. The sintered micro gears had outer diameter of 470μm and 250 μm, respectively. From the sintering results at 1200°C and 1250°C, the grain growth and the degree of thermal etching depend dominantly on the size of micro part rather than micro feature size. The sintering temperature of micro parts should be lower than that of macro components.

Abstract: With advantages of high efficiency and stable quality, UV-LIGA technology is regarded as an important developmental direction of micro forming technology. In the paper, the UV-LIGA production procedure and the processing parameters on fabrication of micro gear were determined through manufacturing experiments. The involute profile micro gear samples and the cases were fabricated based on UV-LIGA technology. The micro gears with parameters of modular m=0.04mm, tooth number z =18 were made of Nickel. The size, elastic modulus and the indentation hardness of the micro gear were measured. The results indicate that the structure of the micro gear is clear, the surface and the curve of tooth profile are smooth, and the sidewall is vertical. Micro gear transmission device was assembled by micro gear and micro case, and it can transmit continuously. The work provided some reference for the fabrication of micro gear transmission device.

Abstract: A Micro Wire Electrical Discharge Machining (MWEDM) prototype is developed for fabricating micro complex parts. It mainly includes granite basement, micro energy pulse generator, precise servo mechanics, detection and servo control system, constant tension winding systems. Experiments are done on the prototype. Experimental results show that: the peak current and pulse duration have obvious influence on surface roughness and machining time, and they also have an optimum value for the highest cutting speed. The servo reference voltage also influences the surface roughness and machining time. Utilizing micro wire electrode with diameter in 30m, the MWEDM can machine micro slot with minimum size of 38m, which proves that the discharge gap width can be controlled not more than 4um, and so small discharge gap is beneficial for part’s machining accuracy. All kinds of complex micro part (such as micro gear, micro bearing bracket, micro shaped holes, etc.) can also be machined by this prototype.

Abstract: Micro hobbing technology is an extension of traditional technology in small scale for processing micro gear. The micro gear shaft which module is 0.175mm is processed by micro hobbing technology. The tooth profile of the micro gear shaft is perfect and the tooth is divided evenly, the burr of the edge is small and the surface roughness is high enough to achieve the requirements of the micro gear shaft. In paper, the design of micro gear hob and the micro hobbing technology is the key factor to the manufacture of micro gear and is presented detailed. The result shows micro hobbing is a good way to process micro gear and it has some advantages including the high efficiency, accuracy in tooth profile, lower cost and widely range of suitable materials. micro-hobbing technology has significance value to research and can be applied in manufacturing the micro gear.

Abstract: WEDM (Wire Electrical Discharge Machining) is an effective method for machining micro gears. In this paper, aiming at WEDM characteristics, the gear design method is discussed. Based on gear meshing theory, the gear tooth profiles are generated. Mesh interference and wire path for WEDM algorithms are presented. Micro gear CAD/CAM software is developed whose functions include gear modeling, interference judgment and wire path generation. Finally a pair of micro gears is manufactured to verify the work in this paper. With the above method, the constraints on some gear parameters can be eliminated and the micro gear design is made more flexible.

Abstract: A new micro-forming method, combining a metal’s super-plastic behavior with hot extrudsion technology, has been developed for manufacturing micro-gear from brass H62. The micro-gear, which modulus m = 0.125mm, pressure angle α = 20°, number of teeth z = 6, tip diameter d = 1mm, was selected and its dies were designed with a better die approach angle based on the DEFORM-3D FEA simulation results of the hot extrusion process. Finally the micro-gear was successfully hot extruded at 650°C from blank Φ3mm×3mm with extrusion ratio about 17. A good dimensional accuracy for micro-gear was obtained by using this hot extrusion technology. In the special die set, the split die structure was designed, and the special die materials were chosen, such as the pressure ram was made of tungsten carbide, and the other dies were made of mold materials 4Cr5MoSiV1.

Abstract: Microfabrication is a kind of critical technology for the development of Micro Electro-Mechanical Systems (MEMS). The frequently-used microfabrication technologies are electric discharge machining, photoetching, LIGA and laser fabrication, et al. Micro structures may be fabricated by these technologies. The polymerization principle of two-photon of femtosecond laser is different from that of single-photon. Photoinitiator of photosensing material absorbs two photons simultaneously to accomplish energy level transition and to induce the material to occur photochemical reaction. For the material absorbing two photons, the energy of each photon is equivalent to half of the energy that needed by the material transiting from ground state to excited state. It is also equal to half of the energy needed by the material occurring single-photon absorption. Therefore, the photonic frequency of two-photon excitation light source is half of the single-photon light source. According to two-photon fabrication principle, machining system of two-photon of femtosecond laser is set up. Which includes light path transmission equipment, three dimensional micro displacement scanning stage and control software, et al. Involute micro gear is fabricated by two-photon of femtosecond laser generated by the system.

Abstract: A bio-etching method using Thiobacillus ferrooxidans (T.f.) for processing micro-gear has been developed. The principle of bio-etching method is that certain microorganisms in nature consume some metal ions to be energy during their growth. The strain of Thiobacillus ferrooxidans consume elemental ferric and cooper ions as its energy source, so T.f. is selected as bio-etching tool, Leathen culture medium is selected as culture medium of T.f., and the thin copper sheet is used as the processed material. During the micro-gear is processed, firstly, thin copper sheet of 0.05mm is cleaned in the acid liquid and some materials such as dirt and grease are cleaned away, then, the anti-erode film is applied to the surface of thin copper sheet, then the surface of thin copper sheet is irradiated by ultraviolet under the condition that the surface is covered by mask film and developed, the anti-erode film that not covered by mask film will be dissolved and cleaned away, after that, thin copper sheet is put into the T.f. liquid and agitating, after the 3h, micro-gear is obtained. The result is showed that micro-gear can be processed by bio-etching method.