Papers by Author: Hai Guang Zhang

Abstract: To solve vacuum casting process exist two-component polyurethane difficult to uniform mixing problems. A non-symmetric eccentric large blade agitator was proposed and the speed was period changed to strengthen the mixed effects. A fluid dynamics of variable speed agitator tank was proposed to numerical simulation flow behacior with Euler - Euler two-fluid model and the dynamic mesh (SM) method. Though numerical simulate to study flow field characteristics of variable speed agitator tank.. The experiment results show that the proposed method can not only achieve high viscosity polyurethane resin with uniform mixing, and shorten the processing time. Effectively solve the polyurethane resin materials difficult to uniform mixing problems.

Abstract: In the process of vacuum casting, non-uniform flow front velocity about pouring material will lead to casting non-uniform shrinkage and warping deformation. Ideal filling pattern should make pouring material fill into the mold cavity with uniform flow front velocity. Give an optimization method of vacuum casting process, optimize the filling velocity in the filling process by combining numerical simulation and optimization method, and make the flow front velocity of pouring material uniform in the filling process, further reduce the warping deformation of casting. The example shows that the optimal model and the given solution algorithm is feasible.

Abstract: Considering that the problem of traditional process parameters setting in vacuum casting machine is of long period, high cost and inferior quality stability, a kind of hybrid intelligent decision model which combined with case-based reasoning, neural network and fuzzy reasoning were established. First, use the case-based reasoning technology to extract the similar case from the case database. Then, use the initial parameters to run the mould trial. Finally, use the fuzzy reasoning technology to optimize the initial parameters according to the product defects. Based on the above-mentioned intelligence model, the related hardware and software system was established. The actual practice proved that the system is effective and can be used in practical production.

Abstract: Bubbles and craft parameters in vacuum casting are the key factors to the quality of products. How to eliminate bubbles and set optimal parameters are the key technical problems to the automation development of vacuum casting. This paper advances a new vacuum casting automatic control system based on configuration software. Dynamic data exchange（DDE） among control module, detection module and execution module is realized based on the strong capability of communication and human-machine interface in configuration software. The realization of this control system can effectively eliminate bubbles and provide corresponding optimal craft parameters automatically and intelligently. In a word, the efficiency and quality of the products can be improved and the dependency of experience parameters can be reduced in vacuum casting.

Abstract: Based on the analyzing for strengths and weaknesses of the rapid prototyping (RP) and electrospinning technique in the manufacturing of three-dimensional bone scaffold, the defects including RP’s low precision and electrospinning’ low intensity has been found. Accordingly, composite structure forming (CSF) has been proposed. This approach integrates the advantage of rapid prototyping and electrospinning. Furthermore, the modeling method of Scaffold for composition forming has been proposed .At the end, the method of controlling process has been given.

Abstract: As one key technology of Rapid Tooling (RT), Indirect Nonmetal Rapid Tooling (INRT) has been used widely, so this paper analyzed the modeling process of INRT and concluded that the velocity of stirring and casting are key factors which affect products quality and production efficiency. In nature, just need to control the speeds of driving motors. In order to resolve problems of existing modeling equipments, such as strong dependency on operators experience and low control precision, this paper studied an intelligent controller model based on Fuzzy Wavelet Network (FWN) which integrated wavelet analysis and fuzzy neural network technologies. The structure and implementation algorithm of FWN are introduced in detail. After considering the advantages of Permanent Magnet Synchronous Motor (PMSM), the INRT equipments use it as driving motors. Because it is nonlinear, uncertain, coupled, sensitive and multivariable system, this paper made improvement on traditional IP controller, FWN acted as error compensator which can compensate for disturbance influence and trace expected speed in real time. The IP intelligent controller based on FWN can strengthen interference ability. The robustness of this control system has been verified by simulation experiment. This controller realized closed loop control of stirring and casting motor and improved the products quality and control precision of INRT.

Abstract: Bubbles in the manufacturing process are common. The bubbles often lead to the decrease of the product’s surface quality and internal performance. This paper summarized the published researches and applications of the detection and processing for bubble images, of which the advantages and disadvantages were also presented. Based on the above mentioned results, this paper then proposed a new bubble image processing algorithm for vacuum casting process, in which the characteristics of the bubbles in vacuum casting process and the problems possibly caused in detail were analyzed. According to the characteristics of bubbles in vacuum casting process, an image processing algorithms was designed using Matlab. The simulation result showed the efficiency of the proposed algorithm.

Abstract: This paper proposed a new method of automated eliminating bubbles based on vision sense technology because detection and elimination of bubbles of injection materials is key factor which influences the quality of products and hinders realization of full automatic control for the vacuum casting. This method uses vision sensor to replace artificial visual measurement, and adopts processing of the bubbles images to judge the effect of eliminating bubbles instead of experiences of operators. This paper developed a bubbles monitoring control system to realize the automated eliminating bubbles method. The system adopts two-level distributed structure which is consisted of host and slave computers. The slave computer is composed of image acquisition module, controller module and execution module. It is responsible for controlling operation devices to finish vacuum casting. The host computer is responsible for supervisory control which includes human-machine interface module, camera control module and images analysis and processing module. The function of every module is described in detail. The operator is just needed to set relative parameters, and then the system will implement automatically. In a word, the controlling system based on this new method possesses some advantages such as high precision, efficiency and flexibility.