Papers by Author: Shu Huang

Abstract: Considering the efficiency and microscale requirement of melting polymer in micro-injection process, we present an experimental analysis of the CO2 laser irradiating Polyamide 12 (PA12) based on the photo-thermal effect of laser-materials interaction. The orthogonal experiments of laser plasticizing were designed by Taguchi method of Minitab software, the influence of process parameters on PA12 plasticization was investigated, and the effect sequence rule of the experiment parameters to melting depth was analyzed. Accordingly，the optimal process parameters combination on PA12 plasticization were obtained，i.e. laser power 3 W, beam diameter 2 mm, scanning velocity 200 mm/min, scanning distance 0.5 mm and environment temperature 20°C.

Abstract: A silicone mould fabrication technique based on vacuum casting was developed and its reproducibility was demonstrated. Orthogonal DOE method was adopted to analyze the effects of vacuum casting process parameters, and the process parameters that had an influence on the quality of the micro-mould cavities were identified and optimized. Micro-casting experiments were carried out using the optimized process parameters and the replicated micro-gears were obtained, these silicone copies were subjected to thorough analysis for dimensional accuracy against the master pattern. The results showed that the fabricated micro-mould was capable of producing functional micro-parts that were able to replicate micro-features, and micro-gears were successfully transferred from the silicone rubber moulds into PU resin pieces under vacuum conditions.

Abstract: Laser peen forming is an emerging novel process of metal plate bending, which uses laser-induced shock wave pressure to generate an unbalanced residual stress field in the target, the moment of the residual stress causes metal plate to develop plastic bending deformation. The mechanism of laser shock induced residual stress was introduced firstly, then the deforming process of metal plate induced by residual stresses was discussed and the depth of the residual compressive stress was proposed. Effects of processing parameters on the residual stress distribution and plate bending deformation were numerical analyzed. The results indicated that the bending deformation of sheet was relative to laser peening numbers, peening coverage and thickness of plate, the magnitude and distribution of residual stresses could be precisely controlled by adjusting laser processing parameters.

Abstract: . Progressive dies are widely used for the mass production of sheet metal components due to the high productivity, high precision and low cost, but the design of progressive die is a complex and highly specialized procedure. In this paper, a design method of progressive die based on component was presented. Based on the technology of component object module, a number of key techniques in the design of progressive die design were addressed, the knowledge-based design frame system was developed, and the assembling model under UG environment was established. Finally, a practical design process for progressive die of complex panel was demonstrated, and the 3D integrated mould was realized.

Abstract: After the mechanisms of laser peen forming (LPF) were analyzed, the effect of sheet metal’s thickness on LPF was discussed in theory. The analysis model that residual stresses brought sheet bending was established, and the relationship between thickness and arc height of sheet metal was obtained. The process of laser shock wave loading during LPF was modeled, and then the residual stresses and deformation of the peened sheet were simulated by ABAQUS software. The results indicated that LPF use bending moments caused by residual stress to induce deformation, which was agreed with the theory analysis. The curvature of sheet metal induced by LPF decreased as the thickness increased, the arc height formed by bending was inversely proportional to thickness square of sheet metal on the whole. This research also has significance for the control of LPF and the investigation of further experiment

Abstract: As a new fabrication technique based on rapid prototyping, vacuum casting process can be especially used in the stage of products development. In this paper, a self-designed and made silicone mould was used to study process of vacuum casting panel part. ProCAST software was adopted to analyze the melt flowing behavior and effects of processing parameters. The key vacuum casting parameters, such as mould temperature, melt temperature, degree of vacuum and coefficient of heat transfer, on the effects of the filling rate of polymer melt were emphasized to be numerical studied. The results indicate that mould temperature and coefficient of heat transfer have the most important influence on quality of the formed panel.

Abstract: A silicone rubber mould was designed and fabricated to study the forming performance of micro-gear based on vacuum casting technique. The effects of process parameters, such as mould temperature, resin temperature, vacuum deaerating time and curing temperature etc, on vacuum casting quality of micro-gear were investigated. The results indicated that high precision micro-gear can be made in batches by means of vacuum casting of silicone rubber mould, and the vacuum deaerating time has the most important influence on the physical dimension of micro-components.

Abstract: An appropriate finite element analytical model for laser compound forming (LCF) was established with ABAQUS code, and then some key technical issues in the simulations were studied and solved. Numerical simulation of LCF for V-shape was carried out to study bending deformation, residual stress distribution and micro-profile of AISI-1008 steel plate. After the corresponding experiments of LCF, the bending deformation, forming precision as well as the variation of surface integrities were mainly measured and analyzed. The results indicated that anticipated shape of V-plate could be precisely formed, meanwhile distribution of surface residual stress and surface qualities on plate were under good control.

Abstract: A numerical analytical model for both-side laser shot peening (LSP) of specimen with center-hole was established, the influence of the center-hole on peening effect was investigated, and the 3D residual stress distributions of ZK60 specimen after one-side and both-side LSP were analyzed. The results showed that compressive residual stresses were obtained at the both sides of specimen after both-side LSP, with a stress value of -179.41MPa on the bottom surface, much larger than that of one-side LSP. The typical experiment of LSP for ZK60 specimen was carried out and the experimental data were well correlated with the simulated results.

Abstract: Microscale laser shock peening (μLSP) is a novel surface treating technology which oriented to microscale metal components in MEMS. Beneficial compressive residual stress is induced at the shocked region to improve the performance of microstructure based on wave-solid interactions. In this paper, the basic principle of μLSP and mechanism of wave-solid coupling were introduced, the influence factors on strengthening effects, such as micro-size effect, anisotropy, dislocation, stacking fault, grain boundary and surface energy were discussed from the microscopic point of view, the results provide theoretical guidance for further study.