Papers by Keyword: Micro Groove

Abstract: The effect of electrode wear is significant on machining quality, in order to ensure the processing precision of micro-EDM milling, need to give reasonable compensation for the tool electrode. In this paper, based on the model of fixed length compensation method to machining the micro groove with micro-EDM by layered milling experiment, moreover, adopted the orthogonal machining path and the machine vision technology to obtain the stable end of the electrode image after processing, and then determine the reasonable path of trajectory overlap. The experimental results show that, the electrode compensation model can availably compensate the electrode wear, and the processing time is shortened by 50% with the machining method of orthogonal trajectories, and the method can make the residual cut remove obviously, gained good machining precision. We observe the bottom section linearity of micro groove is very good and the processing error of the micro groove depth is about 2 μm by the optical microscope.

Abstract: Using high-speed oil-filled spinning and multi-pass drawing composite machining methods, a micro straight groove of copper tube(MSGCT) with an outer diameter about 3 mm~6 mm was obtained, and the forming mechanism of micro straight grooves was investigated. The key factors of process parameters influence the drawing were analyzed. The experimental results show that the values of drawing elongation increases with reduction and die angle increasing. However, drawing elongation increases firstly and then becomes smooth with drawing speed increasing. Stable-quality MSGCT can be achieved by controlling the drawing process parameters and the configurations of micro straight grooves were observed by scanning electron microscope(SEM). In addition, the high-speed oil-filled spinning and multi-pass drawing composite manufacturing can further improve the capillary force of the micro straight grooves of copper heat pipe.

Abstract: In this paper, a kind of one-dimensional steady-state model is used to analyze and simulate the capillary motion of the working material in micro heat pipe. The character of this model is that it includes the influence of the interface friction, and the influence of the friction to the micro heat pipe’s performance is also simulated and analyzed. The maximum heat transport capacity and the optimizing size of the grooves are calculated by this model. Some experiments have been carried out to evaluate the simulation results.

Abstract: Aiming at micro machining of 3D microstructure of brittle materials with a novel tiny-grinding wheel based on the electro-magneto-rheological (EMR) effect, five conical tools with different cone angles are designed to reveal the effect of the cone angle on the machining characteristics. The distribution of the magnetic and electric fields in the polishing area is simulated using the finite element analysis software, and the machining experiments of micro groove were conducted to confirm the simulation results. Experimental results indicate that the material removal rate increases first and decreases afterwards with the increase of the cone angle, and the section width of micro groove increases but the section depth of micro groove shows a fluctuation phenomenon within a certain range. The intensities of the electric and magnetic fields on the tip of the conical tool with the 45° cone angle are at a larger level in the five tools, which is helpful to form a stable tiny-grinding wheel based on the EMR effect and obtain a better machining effect, so the tool with the 45° cone angle is an effective and ideal machining tool for the machining of 3D microstructure.

Abstract: In order to fabricate micro geometrical shapes by EDM process, micro electrodes as tools are needed. At present, micro electrodes are generated by grinding and/or on-machine EDM operations and then it is well known that efficient productivity of micro electrodes cannot be realized. In this study, a new micro EDM method is proposed, in which, micro electrodes generated in turning operation controlling thrust forces to be zero are utilized. As the results of some experimental evaluations, productivities and availabilities of proposed micro EDM are confirmed.

Abstract: Ploughing technology has been applied in manufacturing micro grooves on the outer surface of copper tube. In order to study the formation of spiral grooves on the inner surface of tube, a FEM model operated on DEFORM is established. Two ploughing processes are simulated. At first, an initial groove is manufactured on the workpiece, and then a nearby groove, which will influence the initial groove's geometry, is manufactured with twelve feeds separately. The groove's geometries, including groove width, inclined angle and fin height, are detected. Geometry comparison between the two grooves show that different feed results in different groove shape. According to the geometry change tendency of grooves, the feed can be divided into three different intervals.

Abstract: A micro-grooving method by ultrasonic machining with a lamination tool has been devised. Thin walls on the tip of an ultrasonic tool can fabricate many grooves on a workpiece by one ultrasonic-machining process. Thinner wall for fabricating micro grooves, however, poses the lack of the stiffness of the tool, resulting in the difficulty of the grooving. Then the walls are enfolded with a soft material such as a polymer plastic to supplement the lack of the stiffness. Since soft material absorbs the energy of the ultrasonic vibration, the damage by the impacts of the abrasive particle on the workpiece surface under the soft material is little. Therefore multiple micro-grooves can fabricate efficiently by using of a lamination tool in which thin hard-materials and thin soft-materials are laminated alternately. In this paper, the lamination tools were developed with a thin shim-sheet as the hard material and an epoxy adhesive as the soft material. The fabrication experiments of the parallel grooves on alumina ceramics were conducted. This paper investigates the influences of the parameters of ultrasonic machining such as the grain size of the abrasive particle, the static machining load or static normal stress applied to the tool-workpiece contact region and the grooving time upon the characteristics of the micro-grooves. The results show that the grooving efficiency depends on the grooving time and the static normal stress. Finally, some applications are shown.

Abstract: The manufacturing process of micro-grooves inside thin-walled copper heat-pipe is always complicated and difficult. Separately adopted GCr15 and W18Cr4V multi-tooth mandrel, a series of experiments have been done to machine axially inner micro-grooves of micro-heat-pipe with oil-filled steel-ball spinning technology to analyze the mandrel effect and failure mechanism. It was studied how the tooth-shape of multi-tooth mandrel affects the inner micro-groove shape of the copper tube and how the working position of multi-tooth mandrel affects groove-wall surface morphology and groove path. The wear and fracture characteristics of multi-tooth mandrel are introduced. It is proved that the form of GCr15 mandrel failure in machining micro-grooves is tooth-broken or tooth-collapsed, and its service life is short. Differently, the form of W18Cr4V mandrel failure is felt wear, and its service life is long.

Abstract: This research aimed to develop a novel two-stage micro injection compression molding (μ-ICM) process for fabrication of plastic diffractive optic elements (DOE). The DOE was designed with the spherical coefficients and the Fresnel lens. A piezo actuator was installed inside the mold plate for activating the mold insert for the second compression motion for micro ICM of the DOE lens. The first experiment proceeded to find the operation window of Fresnel lens and then compare the product weight of flat spherical lens by injection molding (IM), injection compression molding (ICM) and μ-ICM. The second experiment was to investigate the effectiveness of micro compression activated by the piezo actuator by the transfer ratio of grooves (TRG) of the DOE lens with spherical lens and Fresnel lens. Results showed that the μ-ICM of the DOE can obtain the highest TRG than that of IM and conventional ICM processes. Therefore, results of this research can be explored to related aspheric optical elements with micro features, such as fine lens used in the zoom lens of camera.

Abstract: In this study, powder blasting techniques are applied for micro groove forming on the developed AlN/hBN composites. First, material properties of the composites are evaluated according to the variation of h-BN contents. And, a series of required experimental works are performed to determine optimum powder blasting conditions for micro groove forming. The experiments are performed for the prepared samples with masked patterns. As the results, it can be observed that the machiniability of the developed AlN/hBN composites increases as h-BN contents in the composites. Also, from the experimental results, it is possible to determine the optimum blasting conditions for micro groove forming on the developed AlN/hBN composites.