Abstract: The experimental modal analysis (EMA) applied in vibrating solidification and vibrating ageing of the cast iron elements has been discussed in this paper. The stimulating frequency、excitation area(wave crest)、supporting area and the way of excitation of this cast iron element can be chosen accurately according to the eigenvalue of vibration parameters and the dynamic display of the measurement. If multiple excitation is needed，the principle natural frequency can be adjusted according to the dynamic display as the partial differences and the characteristics change of the elements. The experiment shown that using EMA excitation parameters can get a better technical effect than those of static solidification、heat ageing or other experience excitation ageing. Vibrating solidification can make a fine crystalline and the hardness of the full section is relative high; Vibrating ageing can get a better stress distribution and raise the ability of anti-deformation.
Abstract: Unidirectional solidification is a method of producing slab ingot for special heavy plate, when compression radio is more than 2.5, internal soundness of slab ingot is assurance, and the nature of Z orientation and percent of pass through supersonic flaw detecting are increased. Products are used in oil drilling platform in ocean ,separator of steam turbo-alternator with more than 0.6 million kW, anchor gate of large-scale hydropower station, shell of nuclear power plant, armoured plate of aircraft carrier. According to dissection on 28t large-sized slab ingot, simulation experiment of crystal, and analogy calculation of heat transfer and coagulation with CFX software, histology features and key to manufacturing technology of large-size unidirectional solidification slab ingot were mastered.
Abstract: The three layers clad strip was fabricated by a vertical type tandem twin roll caster for clad strip (VTTCC). The effect of the casting conditions of the base strip and the overlay strip on the interface between the base strip and the overlay strip was investigated. The temperature of the molten metal and roll-load were investigated casting conditions. Base strip was AA8079 and overlay strip was AA6022. The proper melt temperature of the overlay strip was around the liquidus line of the base strip. The proper roll-load, which was smaller than rolling, was existed.
Abstract: The relationship between properties of BF-WPC and the content of BF were studied, when wood-plastics composite (WPC) was reinforced by 12 mm and 3 mm short basalt fiber (SBF). The results showed that there may have some uneven distributions of SBF in WPC, when the content of 12 mm BF exceeded 30%. Restricted to the uneven distribution and the quantity of “end weak’’, it formed the close comprehensive property of BF-WPC by the length of 12mm and 3mm BF. The comprehensive property of BF-WPC has a maximum range of 15%-30% of the content of 12 mm BF. Compared to pure WPC, the tensile and bending strength of BF-WPC have improved. However, the reinforce effect of BF-WPC is different and is dependent on the index of each property. The BF-WPC plate can be developed with different properties and be a cost-effective material by choosing different length and content of BF.
Abstract: To improve the measurement accuracy of the articulated coordinate measuring arm (ACMA), the measurement system’s parameters must be calibrated. The mathematical model and the disturbance of the kinematic parameters’ error are critical to the calibration precision. In this paper, product-of-exponential(POE) model is adopted to establish the kinematic model of the ACMA, and an error correction model which utilizes single-point versus multi-pose and the distance between every two points is used to take accuracy and repeatability into account. Then, genetic algorithm is utilized to optimize the error correction model in order to identify kinematic parameters. Experimental results reveal that the proposed calibration method is feasible.
Abstract: The solid-phase reaction experiment and principle were introduced. 1000# SiO2 micromist and CaO powder were used polishing sapphire, with polishing pressure 7.5kPa，polishing speed 60r/min and 40r/min. The process of polishing was separated every 120 minutes. The surface appearance and roughness will be survey in each part. Non-surface-scratch will be achieved after 600min of polishing. The roughness (Ra) was decreased from 395nm to 7nm. Rmax was decreased from 2.98μm to 0.05μm. Rt was decreased from 3.34μm to 0.05μm. Through the analysis of the experimental data of XRD, kyanite phase map and diffraction pattern fitting degree. The fact that quality of sapphire’s surface was improved by using this approach has been proved.
Abstract: Compared with conventional turning, ultrasonic assisted turning demonstrates many advantages in turning of quenched steel. Surface micro-geometry is an important evaluation index of surface quality. In the paper, through the comparative experimental study of surface micro-geometrical characteristics in conventional and ultrasonic turning of 45 quenched steel, it can be finally obtained that the surface micro-geometrical characteristics in ultrasonic assisted turning are better than that of conventional turning, especially when adopting lower machining speed; ultrasonic assisted turning of quenched steel is much easier to realize “turning instead of grinding”.
Abstract: The purpose of this paper is to estimate thermal deformation of machine tool model by using transfer function with time delay. The prediction method of thermal deformation based on frequency domain is constructed from transfer function between specified surface temperatures and the relative displacement in cutting area. The relative displacement in cutting area is predicted using two specified surface temperatures near heat source in machine tool model. As a result, the method can be predicted with enough certainty at what rate the temperature changes the most rapidly on machine's startup transient behavior. The method proposed in this paper is remarkably effective to estimate thermal deformation and confirm that the error between experimental and estimated values will be remarkably reduced.
Abstract: This paper reports a gasbag pressure (GBP) mechanism for soft UV-imprinting. With this mechanism, the pressure distribution over the whole non-planar surface is uniform. In addition, the curved surface and side-direction imprinting also can be achieved. The mechanism employs a gasbag inside a closed chamber, which upon inflation compresses the whole PDMS mold/substrate stack not only from the surface but also from all the sides. The microstructures on the PDMS mold are then replicated onto photoresist coated substrates. The result shows that the pressure mechanism can provide uniform pressure for imprinting. It also provides that fine patterns with good dimensional stability can be replicated with high fidelity from soft mold to photoresist on substrates. The accuracy of replication, even at the edge, has been experimentally verified.
Abstract: Highly accurate manufacture in machining industry cannot be achieved without precise temperature control of the cooling water. However, the machine tool coolers are facing the control hunting of coolant temperature and the dramatic variation of heat load in high-accuracy machining. In this study, experimental investigation on inverter driven compressor for capacity control has been proposed. Effects of using capillary tube and thermostatic expansion valve along with inverter driven control scheme have been investigated comprehensively. Cooling performance and power consumption of the cooler system have been measured at different frequency (hertz) of inverter under specific cooling water temperature. The experimental results reveal that the inverter driven cooler is cost-effective and energy-efficient for high-precision machine tool cooling.