Applied Mechanics and Materials Vols. 37-38

Abstract: In order to avoid communication conflicts in DNC systems, the scheduling tactics adopting a modified guaranteed EDF algorithm to DNC systems’ numerical control (NC) programs transmission was proposed. A condition was given to guarantee all NC machines in DNC systems work continuously. A mathematic model based on the actual expending rate of NC program was established to decide the priority of NC program transformation of all NC machines. A constraint condition for two machines with neighbored priority was proposed to avoid the conflict in the scheduling times. A dynamic scheduling scheme was presented for DNC systems. The validity of the presented method is verified by the practical tests.

Abstract: On account of difficulties of squeeze casting die temperature control, squeeze casting process and factors influencing squeeze casting die were analyzed. On the basis of current heating and cooling ways of squeeze casting die, multiple factors and variability of die temperature influence were studied, a new squeeze casting die temperature control model was established. Fuzzy Control was chosen as the control system pattern. After designing the fuzzy controller, simulation model of die temperature control system was set up in the Simulink block of Matlab, and moreover, simulation was performed in it. The simulation results show that the system has good control performance compared with the traditional PID control mode.

Abstract: Traffic incident influences the security of people in the popularity of navigation. It is urgently necessary to develop intelligent vehicles by using new technologies and advanced methodologies. In this paper, a new approach based on holonic conception is presented to study the intelligent control in vehicle tool. The control structure in car is divided into three levels and is defined three holonary, the function of every holon level is discussed, then a distributed multilevel intelligent control architecture in car based on holon is developed. The cooperation relation is analyzed between different levels; the cooperative model is established to study cooperation mechanisms among different holon level, which will help to improve the intelligent control and vehicle security for car.

Abstract: Timely and accurate access to customer requirements is one of the vital elements of the customer-centric business strategy of modern enterprises. After comparisons of different methods of surveying product and market requirements, we propose to use the Internet information through well-constructed websites to utilize the techniques and methods of collecting customer needs and combining with actual cases in order to provide the basis for new product development in enterprises.

Abstract: The principles of jet electrodeposition orientated by rapid prototyping were introduced. The nanocrystalline nickel parts with simple shape were fabricated using jet electrodeposition. The microstructure and phase transformation of nanocrystalline nickel were observed under the scanning microscope and X-ray diffraction instrument. The results show that the jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The nickel parts prepared by jet electrodeposition own a fine-grained structure (average grain size 25.6nm) with a smooth surface and high dimensional accuracy under the optimum processing parameters.

Abstract: In conceptual design, a number of design concepts and alternatives would be generated. These concepts and alternatives usually need to be evaluated to reduce the search space. However, it is not easy for the designers to determine which alternative is better, especially in the design environment where multiple designers might be involved. Current researches mainly focused on the evaluation models, but rarely provide the integrated tools to assist the evaluation process. To address this problem, we propose a web-based collaborative design evaluation platform and two evaluation principles for different evaluation situations. A design case is used to illustrate the evaluation process, where it is necessary for the designers to select a working phenomenon for the “generate force” subfunction of a nailing machine.

Abstract: This paper proposes a novel three degrees of freedom parallel machine tool. The parallel machine tool consists of three serial chains and a fixed base and a moving platform which can be moved in a pose space corresponding to the three degrees of freedom. By using matrix methods, a error model of the parallel machine was developed. The explicit solution of the error of joint and the stroke error of telescopic link were solved for analysis of influence factors of error on the position of moving platform. It provided a theoretical foundation for error compensation of parallel machine tool.

Abstract: Complex equipment usually needs to be designed according to a working environment, for example Tunnel Boring Machine (TBM). But the environment can change in an unanticipated way, which usually leads to inferior performance for equipment and ultimately results in a great loss. Thus how to rapidly respond to unanticipated environment changes (UEC) is an important issue to be resolved for existing products. This paper discusses the adaptable redesign of existing equipment, which performs adaptation or adding new components in existing equipment, avoids redesigning or remanufacturing new equipment so as to quickly meet expected performance requirements. For a complex equipment with many interrelated parameters, there might exist couplings and even contradictions in the redesign. And it is difficult for engineers to determine how changes in certain parameters affect the system performance. The key issues of the redesign are discussed including function-structure analysis, structure change propagation prediction and contradiction resolving. The design issue is analyzed in an existing TBM responding to unanticipated ground changes.

Abstract: The air-lubricated pneumatic workbench introduced in this paper is used in rotary ultrasonic machining which are widely used to machine hard and brittle materials. It is necessary to use special ultrasonic machine tool for rotary ultrasonic machining in the traditional ultrasonic machining, limiting the application of ultrasonic machining. A new type of rotary ultrasonic grinding cutter is developed, which can be mounted on the general purpose machine tool used to machine the hard brittle materials. The air-lubricated pneumatic workbench on which the workpiece is fixed can be used to precisely control the force between the workpiece and rotary ultrasonic grinding cutter when machining. Based on the experimental results of the pneumatic workbench which has been manufactured we find that the force between the workpiece and rotary ultrasonic grinding cutter can’t be easily controlled for the rolling bearings used in such workbench and the rolling friction force between the rolling bearing and guide way. This paper describes a novel pneumatic workbench where we replace the rolling bearing with air bearing which introduces essentially zero friction between the air bearing and guide way. The stiffness of the air-lubricated pneumatic workbench has been calculated in this paper.

Abstract: The bed is a main component of the large precision linear rolling guide CNC grinding machine tool. Its thermal-structure characteristics affect on machine tool’s machining precision and stability directly. In this paper, boundary conditions on the bed of a machine tool factory’s production are analyzed; using FEA method, the bed finite element models for thermal-structure coupling analysis are established and then calculated. By analysis, the simulation of the CNC machine tool operating conditions can effectively obtain the distributions of the bed temperature, thermal deformation and thermal stress; and the results are closed to the true situation.