Key Engineering Materials Vols. 392-394

Abstract: When using meshing creating method of FP (fiber placement) track, once the track point falls at some vertex point of mesh element, in the meantime the vertex point happens to be shared by several mesh elements, there needs a reasonable calculation method to select next mesh element which the FP track will pass through. Then it comes to the problem on linking of FP tracks. In order to solve it, in this paper, the author puts forward a new method, in which parallel projection theory is used, project need analytical mesh element and FP reference vector to a sound projective plane, on which the mesh element be selected and the FP track be calculated, then the FP track would be projected back to the placement surface. Program using this method realized a reasonable joint at the shared vertex point of meshing elements, which the FP direction has little change, and the mutation of track doesn’t come forth. So, the correctness of the method, which putted forward in this paper, is proved.

Abstract: Process Measurement is a measuring method which is accompanied with process of the manufacture of work piece. This paper puts forward a new concept of fluid process measurement, and provides four types of fluid process measurements, which are, pressure pneumatic process measurement, flow pneumatic process measurement, pressure hydraulic process measurement, and flow hydraulic process measurement, and establishes the mathematical and physical modal for them. This paper also provides an example of the application of this measurement method. This measurement has a good prospect, because it can deal with the work pieces with high-precision, complex shape and which are hard to be measured in the machining process.

Abstract: In this paper, a measurement system of temperature field in laser molten pool by CCD based on DSP is presented. The paper also presents the system of hardware, software process, and the method of image processing by DSP. To solve the real time problem in the processing of measuring the temperature field, the system uses DSP as the main CPU, processing the image without a computer. By this method, the system can become simple and efficient and measure the laser molten pool temperature field quickly and exactly. Gradient image of temperature field is displayed on LCD after real time processing by this system. The final picture of temperature field can be directly analyzed.

Abstract: A parameter equation based on cutting edge of ball-end mill is set up by analyzing the parameters of ball-end mill influence the milling force in virtual NC milling process. The relationship among elemental cutting force, instantaneous radial chip thickness and cutting edge length is analyzed, and the dynamic milling force of ball-end mill at arbitrary feed direction is established. The milling force parameter model by quadratic regression equation in different cutting conditions is built. Through experiments in NC machining center and using orthogonal combination and principal components analysis, the regression coefficients are calculated. The correctness of milling force model is testified by experiments. All these can provide theoretical basis for physics modeling and simulation of virtual numerical control milling.

Abstract: The hardware and software design method of reconfigurable embedded NC system which makes use of FPGA’s abundant logic resources and programmable characteristics is presented. It introduces the scheme of a embedded NC system which has regarded FPGA as the control center. It mainly represents the thought of reconfigurable design, the speed control of stepping motor, and the communication of FPGA and PC. As a result, this system has fast response and strong reconfiguration ability. It can reduce the number of peripheral interface devices and result in costreduction.

Abstract: It is an important performance for gyroscopes to read out the angle information of the gyroscope rotor accurately. There are few methods for measuring the deflection angle of gyroscopes, and they are only fit for the special rotors. A new method based on laser triangulation with position sensitive device (PSD), and the calculation theory of measuring the deflection angle are presented in this paper, which is designed for measuring the deflection angle of a new type gyroscope rotor, and can improve the precision of measuring by several reflections. It indicates by calculation that the method presented in this paper is feasible, and the precision can be improved several times by many reflections, furthermore, the more the number of reflection is, the higher the precision of measurement is improved.

Abstract: In order to research the relationship between grinding wheel wear and the signal of grinding strength and grinding vibration, the grinding strength signal and grinding vibration signal under different wear condition were carried on digital processing by time-domain, frequency-domain, and wavelet-pocket analysis, and characteristic signal reflecting grinding wheel wear condition was obtained. Grinding wheel wear was monitored by time-domain statistics average value of grinding strength and energy value of three layers wavelet-pocket decomposition frequency band. The method how to set design parameters of neural network is introduced, and their value in condition monitoring network is determined. Mapping model of grinding wheel wear and characteristic signal is established. Recognition effect is satisfied in the experiment of grinding wheel wear condition monitoring. It confirmed the model is reliable and effective. The result shows that the new intelligent monitoring method is effective on monitoring grinding wheel deactivation condition. One new method of diamond grinding wheel wear condition monitoring under precision and ultra-precision grinding is introduced.

Abstract: A semi-artificial thermocouple device is developed to explore the dynamic cutting temperature variation rules in high-speed milling of Al7050-T7451 aluminum alloy. Both the aluminum-constantan thermocouple calibration diagram and cutting temperature curves are obtained. The cutting temperature empirical formula is constructed by means of orthogonal experimental design and multivariate linear regression analyses. It shows a reasonable good match between the theoretical predicted values and the measured temperatures. This allows for the optimization of cutting parameters and the exploration of machining deformation induced by the cutting heat in high-speed milling of aerospace aluminum monolithic constructions.

Abstract: One main method of chip breaking is to use the grooves which can make chips be broken. 3D complex grooves meet the requirements of controllable chip breaking. It is too complicated to design 3D complex grooves using AutoCAD in short periods because each section of them is intricacy. Thus the author established the parametric model of the groove based on the advanced functions of Pro/Engineer, in which parameters can be obtained, transferred and modified through setting up parameter relations and compiling control programs. The combination of representative elements constituting the solid model of 3D complex grooves can be achieved by just inputting parameters, which can be directly transformed into 2D drawing accordingly; the heavy work of drawing complex surfaces using AutoCAD can be avoided; and the curvature of each normal profile of grooves are gotten. All such work lays a foundation for the groove design and optimization.

Abstract: According to the processed materials, characteristics of their shapes, process precision and other conditions, a fuzzy neural network (FNN) can be trained with experiment data. The trained network can automatically select process parameters by using the fuzzy neural network (FNN) technology, and the selected process parameters can be saved in the computer in file. In this way, the selected process parameters can enter into the process program during the programming and the automatic selection can be accomplished, so that full automatic achievement of NC process program is feasible.