Key Engineering Materials Vols. 392-394

Abstract: The different uses of NC grinding machine with ganged revolving spindle and the requirements to NC grinding machine for several special uses are discussed. A multifunctional three axes ganged NC grinding machine with patent right is introduced. Its ganged revolving spindle is changeable. Therefore it can meet the requirements of different uses. When the ganged revolving spindle works as headstock spindle, the NC grinding machine can be used for machining cylindrical cam, plate cam, noncircular shaft and so on. When the ganged revolving spindle works as a revolving spindle of dresser, the NC grinding machine can be used for dressing form wheels with multifarious curved generatrices accurately. With simple mechanism, wide flexibility and simple NC programming, it is especially fit for laboratory use. A new-style NC dresser with invention patent right is also introduced.

Abstract: Nanoindentation device has the ability to make the load-displacement measurement with sub-nanometer indentation depth sensitivity, and the nanohardness of the material can be achieved by the load-displacement curve. Aiming at the influence law of indenter tip radius to indentation hardness, testing on the hardness of single-crystal silicon were carried out with the new self-designed nanohardness test device based on nanoindentation technique. Two kinds of Berkovich indenter with radius 40nm and 60nm separately were used in this experiment. According to the load-depth curve, the hardness of single-crystal silicon was achieved by Oliver-Pharr method. Experimental results are presented which show that indenter tip radius do influence the hardness, the hardness value increases and the indentation size effect (ISE) becomes obvious with the increasing of tip radius under same indentation depth.

Abstract: In order to achieve higher product quality for sculptured surface productions, an advanced strategy are proposed for machining planning, namely a tool-posture-control strategy. In the tool-posture-control strategy, machining chatter is reduced by controlling the machine rigidity along cutting feed direction. This proposed strategy, which improved product quality of sculptured surface when subjected to both the part geometry and the machine rigidity constrains, is described in this paper. A new machining-planning aid called local stiffness index is developed to help tool posture planning. This proposed strategy subjected to multi-constrains help a part programmer to choice the optimum tool posture. In order to illustrate the application of stiffness index map and the proposed strategy, the applications of the proposed strategy to real three-dimensional complex surface (e.g. a turbine blade) are presented in this paper.

Abstract: Man-machine cooperative teleoperation and multi-control modes transfer in due time are the key problems that the telerobot system must deal with. That is the intelligence of the operator and the robot in the system should be distributed appropriately according to the current task state. The current task state of the telerobot system should be evaluated to solve these problems. So the telerobot control system is built with current task state evaluation after analyzing system control modes. For the control modes transfer in due time, its Petri Net (PN) model is built and it is simulated with the Stateflow module of Matlab. Simulation results show the validity and rationality of the model.

Abstract: According to the structure features of turbine blade, the analysis of the grinding motion has been done and, based on the restriction conditions, the structural configuration of belt grinding machine has been described. Then the configuration of the control axis of belt grinding motion and the machine tool structure has been determined. The kinematics model of the blade grinding has been built by the motion control chain of the machine tool. The tool path algorithm of belt grinding has been proposed with STL 3D data model of blade surface. Based on IPC and Programmable Multi-Axis Controller PMAC, the CNC system of turbine blade belt grinding machine has been designed. Finally, the prototype of Turbine Blade CNC Belt Grinding Machine has been made.

Abstract: Based on definitions of tissue engineering scaffold with defect bone, the constructing method for its exterior features was presented. First the pixels of picture at defect area were filled up and then the Boolean operations of filled pixels and original bone pixels were executed, and finally, all the area of filled pixels was 3D reconstructed to obtain the exterior features of scaffold. The 3D-reconstruction idea of the exterior features of scaffold and related projection and Boolean processes of model data for defect area were also analyzed.

Abstract: In this paper, we investigate the relationship of heating current in Electric Hot Machining with tool life, cutting parameters and machined surface roughness. Experimental results indicate that there is an optimal heating current in EMH in which the effect of hot machining is the best. A method of rapid determining the optimal heating current under various cutting conditions in EHM is proposed according to the conservation law of optimum cutting temperature. That is, for a certain combination of tool and workpiece, the heating current relative to optimal cutting temperature in different conditions can be found by changing heating current and measuring cutting temperature to meet the control object of temperature in EHM. The PID control principle and effect of computer monitoring system for realizing optimal heating current control in EHM is also introduced.

Abstract: The mathematic model for polymer extrusion has been established by using the penalty finite element method, and the analysis program has been coded. The driven and pressure flow of power-law fluid in compound shaped part of co-extrusion process of polymer with metal insert has been simulated. The velocity field and temperature field of polymer flow in die cavity are obtained though solving the momentum equation and energy equation, and the influence of various metal insert velocity on the polymer flow is studied. The potential defect is forecast, and the improved measure has been given further. It shows that the common rule of the compound shaped part of co-extrusion process of polymer with metal insert is given by the analysis of the example. The simulation results are very important for the process and die design of the polymer co-extrusion with metal insert.

Abstract: In this paper, the mathematical model with two associated coordinates is established for two-dimension ultrasonic vibration group system by impedance analysis, and natural frequency equation of 2D vibration system is deduced by which the influence of natural frequency change of individual components on the natural frequency of group system is analyzed. Amplitude-frequency characteristics of system were tested which verified the correctness of the theory. In simulation experiment on large plate under two-dimensional ultrasonic vibration grinding, superimposed tracks of a number of irregular ovals exist in vibrating plane, that is different from previous research that only one simply oval track exists in the vibrating plane apparently. The results supply a reliable theoretical and experimental basis for the further discussions on the abrasive removal mechanism under two-dimensional ultrasonic vibration.

Abstract: For carrying out real significant open with regardless of operation system platforms, the open CNC system based on quantum framework was established. The paper introduced principles, architecture and content of quantum framework. And the architecture of open CNC system based on quantum framework was designed. On the basis of architecture, parts of finite state machine modeling of CNC active objects and programs were given in this paper. The results show that quantum framework is a kind of software-bus which can achieve open characteristic of software and loosely coupled of CNC function modules. So the quantum framework carries out real significant open.