Papers by Keyword: Process Parameter

Abstract: In this paper, a vacuum freeze drying equipment was developed for vacuum deacidification of paper relics. The relation between freezing velocity and sample mass was studied experimentally, so did the relation between freezing velocity and pre-freezing time. The results indicated freezing velocity is inversely proportional to sample mass as well as the time used with refrigerating capacity equal to mass fraction of frozen water. Problems like melting or disintegration can be overcome by heating gradually. Radiation heating combined with conduction heating make sure the sample is heated evenly. Moreover, vacuum deacidification is available to remove acid of paper relics, and paper relics are kept intact by means of vacuum freeze-drying.

Abstract: In the present work, the role of tool radius in suppressing forming defects in SPIF process is investigated. It is shown that a strong correlation exits between tool size and defect appearance. Moreover, there is a certain limit on choosing low limit of tool size for defect-free forming. A formula has been proposed to asses this limit under varied forming conditions.

Abstract: During graphene oxide separation process, the effects of the process parameters such as centrifugal separation time and ultrasonic treatment time on the particle size distribution of graphene oxide aqueous dispersion were studied. The results show graphene oxide has the narrower particle size distribution and the smaller nominal effective particle size with increasing the centrifugal separation time from 20 min to 160 min. And there is a critical time in the ultrasonic treatment to obtain the narrower particle size distribution and smaller nominal effective particle size of graphene oxide. Graphene oxide has the narrower particle size distribution and the smaller nominal effective particle size when the ultrasonic treatment time is 4 h.

Abstract: The deformation seriously affects the quality of the products, which is one of the common defects of plastic parts in the injection molding. Factorial design and CAE technology was used to study the product's warping rate influence in this paper. The minimum warping rate was obtained through the Minitab software and the optimized process parameters are verified with the Moldflow software. Experimental results show that the optimization design is effective and the warpage of the product is reduced.

Abstract: In recent years friction stir welding process has received a great deal of attention from the transport industry. During the process, heat generation and material stirring induce significant microstructural alteration in the base material, affecting the properties of the welded assembly. In this paper the influence of process parameters, namely rotating speed and welding speed, on mechanical properties of AA2024-T3 friction stir butt welds is experimentally investigated. An increase of the yield stress has been found decreasing the heat input, while an opposite variation was measured for the elongation.

Abstract: The non-smooth surfaces on 45 steel were prepared by laser cladding with KF-300A alloy powder on the basis of the bionic non-smooth morphology of shark scales. The rib-type coatings were composed of hot-rolled steel 45 and clad layers containing hard phases such as WC/W₂C. In this paper, the influence of laser power and defocusing distance on the quality of cladding layer were investigated. The microstructure of the coatings was analyzed by scanning electron microscopy, with attached energy dispersive spectroscopy microprobe, and by X-ray diffraction. SEM inspection of the samples showed that all coatings exhibited similar phases in their microstructure, but the phases presented differ in morphology, size and distribution. Dilution and interaction zone of the coatings were also discussed in this paper. The results showed that the non-smooth coatings were crack-free and had a good metallurgical bonding with 45 steel trenches with a low dilution under the optimum laser conditions (P=700 W, f =14 mm, V=3 mm/s, continuous powder feeding voltage 2.1 V, nitrogen protection).

Abstract: Friction stir welding (FSW) is a relatively new solid-state fastening method which is suitable for joining advanced lightweight metal sheets that are hard to weld. Latest literature relating to finite element analysis (FEA) of FSW process is reviewed in this paper. The recent development in FEA of FSW process is described with particular reference to three major factors that influence the performance of FSW joints: modeling technique, tool design and process parameters. The main FE methods used in FSW process are discussed and illustrated with brief case studies from the literature.

Abstract: This paper presents the original development of an experimental approach in studying the multiple tensile characterizations as key quality characteristics for several different plastic gear materials related to various parameters in injection moulding process. In this study, emphases are given on a new low-cost mechanism for the testing of the injection moulded plastic spur gear specimens with various teeth module. The testing fixture are developed and validated to provide uniform state of tension with series of plastic gear specimens produced in accordance with the systematically designed of experiment. The effects of changes in the process parameters including melt temperature, packing pressure, packing time and cooling time at three different levels on the elongation at break and ultimate strength of plastic gear is evaluated and studied through the proposed experimental approach.

Abstract: By the use of UG software，the solid model of the interior decoration board inside the automobile door was created and the molding behavior of the plastic product was simulated and analysis in the virtue of Moldflow．Based on the analysis of the effect of the mould parameter on the molding behavior ,the best gate location was achieved.We designed the L9(33) orthogonal experiment table of the parts injection molding,selected the mold temperature, melt temperature, injection pressure as the factores .Sink mark index, volume shrinkage, maximumwarping deformation and cavity residual stress are determined as the parts quality evaluation. We completed the orthogonal experiment and the range analyses of the results. We analyzed the influence of process parameters on evaluation of every optimal direction,developed evaluation for comprehensive quality of parts. Finally, we get the table showing the tendency on the assessment of the quality index influenced by various factors, which provides a foundation for the approaching research on the parameters of the injection molding process.

Abstract: Reducing vehicle weight and emissions by lightweight design is a major goal of the automotive industry. Magnesium as the lightest structural metal offers a significant weight saving potential compared to steel and aluminium. Cast magnesium components are widely used, e.g. as engine blocks or gear box housings. The application of magnesium sheets is currently hampered by the low formability of magnesium which means that a large number of rolling passes is required to roll a DC cast slab to final gauge sheet. This large number of rolling steps is the main reason for the high cost of magnesium sheets. Twin-roll casting (TRC) is an alternative, economic production process for the generation of fine-grained feedstock materials that subsequently can be warm rolled to thin sheets. It therefore receives attention in actual research and development projects for the application of magnesium alloys as prospective light metal solutions. This production process for thin strips combines solidification and rolling into one single production step and therefore saves a number of rolling and annealing passes in comparison to the conventional rolling process. The main goal of the activities at the Magnesium Innovation Centre MagIC of the Helmholtz-Centre Geesthacht (HZG) is the development of wrought magnesium alloys and their introduction into industrial, structural applications. The current focus of the research work is on alloy design and their processing for magnesium sheets produced by twin roll casting. In order to understand the influence of process parameters on the microstructure and texture the first twin roll casting experiments were performed with the alloy AZ31 (Mg-3Al-1Zn-Mn) as benchmark. As an example, the influence of melt temperature on the microstructure of the strip is presented and discussed with respect to arising material properties. Optimisation of process parameters of twin roll casting and the subsequent rolling of the sheets, offers the possibility to produce high quality sheet material.