Abstract: The strain in curing process of composite part would be influenced by curing compaction, resin flow, curing action and tool-part interaction, meanwhile these factors would also influence the final cured quality of composite part. In this paper, FBG(fiber Bragg grating) sensors are used to in-situ monitoring the strain of composite parts, which are cured in four different pressure situation by autoclave: 0.0Mpa,0.2Mpa,0.4Mpa,0.6MPa. by analyzing the strain change rule, the part quality is predicted, then the predictive result is compared with some verification method: measurement of part’s boundary dimension, ultrasonic phased array scanning, metallographic analysis. The result shows that, the prediction is consistent with verification, the in-situ monitoring method by using FBG sensor is available for predicting cured quality of composite parts accurately: increase curing pressure is benefit of part compaction, resin flow, and reduce delamination,pores in composite part, finally improving the part quality dramatically.
Abstract: This paper proposes a new filling material, fiber-reinforced ice (FRI), for tube bending. In tube bending, lead and low temperature melting alloys have conventionally been utilized as the filling medium to prevent defects and to alleviate flattening of the tube’s cross section. However, these alloys are usually harmful to the environment (e.g., Pb, Bi-Pb-Sn-In, or Pb-Cd system alloys) or are expensive (e.g., In-Sn system alloys). In this study, the author utilized ice reinforced with the fiber of wastepaper for 3-point bending of JIS G 3452 SGP 32A steel tubes. Compression tests were conducted to analyze whether these tubes have crushing strength comparable to that of conventional fillings and sufficient ductility in low-speed deformation. The filling medium with more fiber effectively yielded less flattening.
Abstract: An electroplated diamond wire tool is frequently used for the machining of hard and brittle materials such as silicon ingots, magnetic materials, ceramics, and sapphires. This study aims to examine the influence of brittle behavior of work materials on machinability (including tool wear); therefore, we conduct dynamic ultramicro hardness measurements and microgrooving experiments for three types of ceramics. The results indicate that the groove depth of a work material tends to increase with the processing time. Moreover, material properties of a work material, such as hardness and toughness, have a significant impact on the fluctuations in its groove depth. However, kerf width of a work material does not depend on the processing conditions and material properties. In addition, a faster relative velocity improves processing efficiency but also increases tool wear.
Abstract: The article is focused on the design of complex component to determine competence CNC milling machines designed to produce shapes with geometric tolerances by observing the shape, orientation and position of the standard EN ISO 1101. 3D model of a technological process for the production of complex components, it will contain the complete design of tools and cutting parameters for individual milling strategy, select clamping and workpiece material, a preview of the generated routing strategies and paths cut surface after each of their simulated. For milling machines with the so-called measurement system for machine OMM (On Machine Measurement), the proposal for a comprehensive parts serve as a reference in determining the accuracy of their measurements of geometric and dimensional tolerances. The main activity of systems OMM is the replace of the tool clamped in the spindle of milling machines with special touch probe which senses by the touch surface contours of produced parts.
Abstract: Both superalloy GH2135 and stainless steel 420J1 were used as test materials to be processed by LASERTEC 80 PowerDrill three-dimensional solid laser processing center. The microstructure of the hole was investigated by super depth of field microscope and laser scanning microscope. The front and back orifice diameter, orifice deposits and thermal effect of accumulation zone were studied. The single factor test method was used to study the influence of pulse energy, pulse width and repetition frequency on the quality of micro holes. The results showed that the front and back diameter of the holes all increase with the increase of pulse energy from 0.4J-3.9J. And the front and back aperture are increase with the increase of pulse width from 0.9ms-1.9ms. Meanwhile, the variation of the aperture and pore taper is more noticeable with the repetition frequency changed from 10Hz-60Hz. The results revealed that pulse energy is one of the biggest influence factors, large pulse energy can lead to small hole taper within a certain range, and short pulse width can reduce orifice debris and splash. Both the recast layer and microcrack were existed in the two kinds of metal materials. The quality of holes drilling in GH2135 is better than 420J1.
Abstract: In this study, a series of deep micro holes were machined on thick GH4169 super alloy by the trepan drilling, using a millisecond pulsed laser which equipped to the numerical control processing system. The microstructure of the holes including surface and longitudinal morphologies, diameter, taper, circularity, micro cracks and recast layer were systematically characterized. The surface morphology and the longitudinal section of the drilled holes were observed by Scanning Electron Microscope and 3D Laser Scanning Confocal Microscope. The method of Minimum circumcircle method was employed to evaluate the entrance and exit end circularity. The results showed that the melt and spattering accumulating around the holes decreased with the augment of laser power. The diameter of the entrance showed an increasing tendency with the growing of laser power, but the exit end was not seriously affected by the power. The micro cracks and recast layer could be found obviously, the micro cracks appeared in those zones which thermal stress concentrated, the thickness of recast layer is about 20μm and the taper and circularity were optimized at a laser power of 80-100W.
Abstract: This research is focused on the helical blades used in the reel mower machine which uses 5 to 10 helical blades. These blades are normally manufactured using the roll forming process which has certain tolerance. This research is to develop an iterative methodology to optimize the manufacture of blades using roll forming. To save cost, time and waste of material the computerized simulation process is being used. The design of the blade and the die for the roll forming and modification are done using software SolidWorks. Simulation is performed using software DEFORM-3D. The simulation result and the actual design are compared using software Geomagic. This study also shows the potential applications of computer aided engineering and its benefits in verifying and reinventing the part manufacturing process.
Abstract: Rolls are important tools in the steel industry. With the increase of the automobile and the mould, rolls are increasing rapidly. Hard rolls are very difficult to cut, almost all hard rolls are cut by only by grinding, and the grinding efficiency is relatively low, and it consumes a lot of cutting fluid. In this paper, the life and tool wear of ceramic tools in different cutting conditions were analyzed. Crack, chipping of cutting tools were analyzed. The experimental and theoretical analysis confirmed that the generation and expansion of the crack are the main wear mechanism of the tool failure, when the ceramic tools cutting cold rolls.
Abstract: During the forming of high-strength steels, edge cracks occur unexpectedly on sheared edges e.g. during collar forming. A non-contact measurement method based on the well-known tensile test was developed. It allows the investigation of the formation of edge cracks under tensile loads and determining general criteria to predict the formation of edge cracks during a specific forming process. The criteria are validated experimentally by means of the collar-forming test. In conjunction with the proposed line-fit-method these criteria can be implemented easily in FEM software in the near future for the prediction of edge cracks.
Abstract: In the hot forging process of TC4 Ti-alloy large die forging two beam, the dynamic recrystallization of α phase and recovery of β phase were happened. Using Deform-3D finite element analysis software, the evolution model of grain and phase is constructed and coupled simulation is carried out, on the foundation of simulation results, the evolution law of α phase dynamic recrystallization and β phase transformation in time and space was obtained, so the optimal control of grain and phase was realized. Thus the performances of TC4 Ti-alloy will be improved and optimized, and all this will provide theoretical basis for the forging of large Ti-alloy components.