Key Engineering Materials Vol. 667

Abstract: In order to ensure the medicinal efficacy and improve the production efficiency, design and production of a kind of microwave vacuum drying medicine extract new technical equipment. Through analyzing the principle of material characteristics of traditional Chinese medicine extract, drying, microwave vacuum drying, Design of microwave vacuum drying chamber, cylinder body, a door body, a material system. Based on the overall scheme, the main structure parameters were calculated, and the production of a set of test equipment, the dehydration rate test. The new process equipment efficiency, reduces the cost, the volume is greatly reduced, keep the efficacy, and has the functions of sterilization, especially suitable for the production of proprietary Chinese medicines industry.

Abstract: With the increase of welding thickness, Friction stir welding equipment (FSW) with traditional milling machine structure could not meet the requirements of stiffness which to support the huge axis load. Therefore, a FSW with serial-parallel mechanism based on 3-PRS platform was proposed. In order to complete real-time control and the actual and virtual axis control of the equipment, the positive solution and inverse solution (based on Newton-Euler method) of the FSW are analyzed. Then, based on the PA system, the open CNC of the equipment is designed, and the inverse kinematics and the numerical positive kinematics based on Newton-Euler method are embedded into the interpolation of NC system. According to the demand of the equipment, human-machiner interface (HMI) is developed to display the positions of actual and virtual axis for the equipment, and compiler and interpolation are designed. At the same time, online real-time 3D motion simulation is designed, space pose of spindle and whole for the equipment are deduced. In the paper, design method of CNC based on the serial-parallel mechanism is provided.

Abstract: The ring-involute tooth spherical gear with two degrees of freedom is considered as the research object. Through the combination of theory and experiment, a further study is conducted on it. According to the theory of rapid prototyping, comprehensive consideration of the ring-involute teeth spherical gear tooth profile surface forming principle and transmission features, traditional machining method, transmission error and the actual application, a fast processing method of the ring-involute tooth spherical gear is proposed. Spherical gear model is built in Solidworks surface modeling environment. Through the use of rapid prototyping equipment, the ring-involute tooth spherical gear is worked out. Tooth root thick, addendum thickness and transmission error of spherical gear is further measured on this basis with the method of rapid forming. Basic parameters meet the requirements. The rapid prototyping processing method is proved to be practical, effective and valuable.

Abstract: Frames are the main components of the flight motion simulator, which are the support for each shaft system, at the same time the rotating load for the external shaft, so the stiffness and dynamic characteristics of the frames in a large extent determines the final accuracy and dynamic performance of the flight motion simulator. For the cast aluminum alloy ZL114A frames of a 3-DOF flight motion simulator, using finite element analysis method, the dynamic characteristics are calculated and analyzed, and then the each order resonance frequency and mode of vibration are obtained. By using of the modal synthesis method and optimization algorithms, the structural dynamics of frames are designed optimally, so as to further reducing the moment of inertia, and improving the stiffness and dynamic characteristics of frames. This method has provided important reference for the reasonable design of the frame structure, and definitively established the foundation to further study the triaxial coupling dynamic characteristics and system mechanical optimization for the flight motion simulator.

Abstract: In order to respond to market rapidly, save design time, reduce the cost and particularly design the machine in a predictable and reliable manner, an approach based on the integration of virtual machine tool and workpiece material removal mechanism is proposed in this article for the investigation of centerless grinding process, the prediction of workpiece roundness generation and the evaluation of dynamic characteristics of grinding system. In this approach the machine structure model is firstly presented by incorporating the kinematic relationship of the feed drive system and the material dynamic parameters of the grinding system. Then the virtual machine tool model is built by the combination of the machine mechanical structure and the control loop. Finally the virtual centerless grinding is realized by integrating the virtual machine and the workpiece material removal mechanism through their coupled surface regeneration mechanism. The comparison of the experimental and theoretical results demonstrates that this virtual centerless grinding approach can investigate the workpiece roundness generation accurately.

Abstract: In this paper, the author constructs a dimensionless nonlinear dynamic model of Vibration cutting system described by nonlinear differential equations. The model is established on the relationship between cutting force and cutting speed and the relationship of cutting depth to the cutting resistance and the time. It is the nonlinear dynamic friction model of vibration cutting considering tool-chip friction. Based on the model and the method of chaotic identification, Lyapunov Exponent, the further research on the vibration cutting produce behavior and its classification are conducted.