Algorithm of Cutter Machining Position during Numerical Controlled Last Carving

Numerical control last making machine is a machine that is used to process shoe last. A new principle of numerical control machining shoe last is put forward aiming at the deficiency of current carving last system. On the basis of the principle, the algorithm of cutter machining position during numerical controlled carving last is analyzed in detail. The complex problem of the calculation of cutter machining positiion is resolved by applying spherical milling cutter that is often used in machining free_curve surface today and taking account of practical situation of the shoe last_making machine. At the same time, the calculation of cutter machining position is realized by program using Visual C++6.0. As a result, the calculation time of cutter machining position is reduced greatly and the efficiency of design is improved. Moreover, the process of carving last is agile and precision of carving last is ensured.     

Worm wheel grinding method of convex pitch line non-circular gear

To overcome the precision machining difficulty of non-circular gear, a convex pitch curve of non-circular gear and worm grinding method is presented. Firstly, worm wheel is reduced to rack cutter and a rack machining convex pitch curves of non-circular gears sport model is set up. Then based on the structure of CNC worm wheel grinding machine tools and machining principle, electronic gear box of machine tools is designed and active and following axes are planned. At the mean time, the synchronous coefficient of machine tools between synchronization is deduced by machining principle of equal arc-length, and interaction models of grinding are established. At last, the worm wheel manual presetting cutter methods with non-circular gear are given and worm grinding wheel mounting angle, axial position and axial location parameter can be adjusted along the gear.     

New Method of Machining Internal Spiral Groove of a Big Lift Angle

There exists muchinterference in machining internal spiral groove with big lift angle and small size, whichis a difficult problem. The design and calculation of tool section is analyzed in this paper while differentcutters are utilized to machine the groove when the tool axis is parallel or skew to that of the work piece. The approximating method of using circular-arc cutter is put forward, which is proved by the calculation and analysis to be a feasible method within range of the permissible error. The digital simulation of machining internal spiral groove which is finished by different methods, such as simulation of tool path, error analysis, verification of the cutter design and so on, has been done through typical software such as the Program files function of I-DEAS and the Manufacturing Module of UG.     

Path planning in 3-D space for robot based on ant colony algorithm

In this paper the ant colony algorithm is applied to path planning problem in 3-D space for robot. First of all, the space between the origin where the robot is located and destination was divided into a three dimensional grid, at the same time the valid path from origin to destination is defined, then all the ants will leave from the origin, selecting next vertex independently in three dimensional grid, to the destination on a valid path. The simulated experiment shows that the algorithm is efficient and has a great convergence rate.     

The key technology research of on-line surface inspection for hot heavy rail

To overcome the detection difficulties of the surface defects when milling a hot heavy rail,a suite of detection system for on-line surface defect is developed. To select optical environment according to radiation of heavy rail and characteristics of light,use multi-linear array CCD cameras to parallel multi-angle collect images of whole surface of hot heavy rail,and obtain images through an image adaptive preprocessing to meet requirements of defect detection. For the condition that the defects extracting causing by continuity of the surface defects of hot heavy rail is hard to realize through traditional image segmentation, an examining algorithm of image relevance between pixel lines is proposed, using pixel de-differentiation and statistical variance operations to extract defect. This algorithm is demonstrated to be better than traditional edge detection,and the system has achieved good results in the practical application of a rail beam plant.     

Applied Data Disposal Technology of Numerical Controlled Last Carving Machine

Necessary technical disposal methods of original last data before carving are introduced in turn.First,data interpolation and smoothness are adopted for removing absent dots and bug dots.Afterwards,all sections of last are rotated and central axis is adjusted because measurement axis and machining axis are not the same.Finally,head and tail of last are designed and appended in order to use clamp to fix last during the machining process.     

Full Aero-elastic Bridge Model Design of Long Span Arch Bridge

Aero-elastic model design is the precondition of full bridge aero-elastic model tunnel tests. The full aero-elastic bridge model design of long span arch bridge is discussed. The effect on the model design of different transverse rod space and bend stiff is analyzed in detail. Different scheme need to be designed according to the transverse rod stiff. Considering the changing section dimensional arches, the method of projecting the spatial arches to the plane arches, then designing the plane arches, at last projecting the plane arches to the spatial arches is proposed at first. The results show that the method is effective.     

Research on Machining Last by Numerical Controlled Last Carving Machine

System structure of last CAD/CAM is described. Then machining principle of system output device named numerical controlled Last Carving machine is introduced. Furthermore, we lay stress on analyzing machining programming method making use of direct numeric definition. Special disposal is taken on step error and working frequency of step motors so that not only error accumulation is avoided but also step motors always work in the best frequency range. As a result, machining precision and speed of last are both enhanced as well as step motors' working safety is guaranteed.     

Three dimensional temperature field visualization reconstruction of charge coupled device radiation image

Aiming at the questions of raceway section two dimension temperature distribution from two dimensional image accumulated by three dimensional radiation space and three dimensional temperature reconstruction error caused by limited charge coupled device (CCD) sensors for a sudden spread combustion chamber, the two dimension rectangle interpolation virtual CCD sensor installation algorithm is provided as a new technology for solving the difficulties of installing more CCD sensors and filtered back projection reconstruction error caused by limited projection numbers. The radiation intensity projection data got from flame image collected from the installed CCD sensors and computed virtual CCD sensors is interpolated for filtered back projection to computer intensity distribution and calibrated bi color method is used to calculation temperature in raceway depth direction. The results of experiments on a mini type coal gas furnace and practice test showed that the algorithm is accurate and credible and realized the on line monitoring for sudden spread combustion chamber raceway depth direction. At the same time, the useful information is provided for further studying combustion working state for the sudden spread combustion chamber.     

On line tool breakage monitoring method based on power information and cross-correlation algorithm

In order to reliably monitor unexpected tool failure and prevent workpiece or machine tool from possible damages in batch machining, a tool breakage on-line monitoring method based on power information and cross-correlation algorithm is proposed. In this method, wavelet coefficients of spindle-power signal are used as the characteristic vector of machining information, and then the vector sequence extracted from a normal machining process via Mallat wavelet is defined as the reference template for monitoring cutting tool condition. In batch machining, real-time characteristic vector of the workpiece in machining process is extracted via an improved real-time wavelet algorithm. The correlation of two vector sub-sequences within a sampling time window, which is described by generalized cross-correlation coefficient, decreases apparently when the tool is broken. The generalized cross-correlation coefficient is defined as tool condition index (TCI), and tool breakage can be detected by monitoring the TCI with a threshold value. Experiments show that the method can accurately identify tool breakage failures in normal machining condition, and thus it is practical.     

The Analysis of Bending Deformation of Cutter Tooth and Gear Tooth During Shaving Process

In this paper,the variation pattern of the contact point on cutter tooth and gear tooth is analyzed during gear shaving process. According to the shaving force measured by dynamometer, the deformation of cutter tooth and gear tooth at the contact point is calculated by appying the three dimension finite element method. The deformation curve of cutter tooth and gear tooth are obtained by analying deformation in shaving domain. It is the basis of studying relation between shaved amount and deformation.     

CONDENSATION HEAT TRANSFER ON THE THREE-DIMENSIONAL EXTENDED SURFACE TUBE ATTACHED BY A POROUS DRAINAGE STRIP

An experimental study was carried out for the condensation heat transfer on the three dimensional extended surface tube attached by a porous drainage strip. The results show that the combination of the three dimensional extended surface and the porous drainage strip is the effective method enhancing condensation heat tiansfer on the horizontal tube. The change of the shape arid depth of the axial grooves results in a 10% vaitation of condensation heal transfer coei ficienls. In the range of the experiments, for aocohol as the working fluid, the enhancement is up to 152%, and for water, 185% as compared with the horizontal low-finned tube.     

Experiments on Convective Heat Transfer for Various Media Flowing Turbulently in Tubes with Three Dimensional Internally Extended Surface

This paper presents the experimental results of convective heat transfer performance in 5 copper tubes with three dimensional internally extended surface, with flow of various test fluid in the Reynolds number range of 8,000 to 80,000. Water and mixture of ethylene glycol with water (the ethylene glycol weight content equals 55%) are chosen as test fluid. The effect of the physical properties for test fluid on heat transfer performance in the tubes with three dimensional internally extended surface is discussed. The heat transfer correlation is obtained by the experimental data.     

OPTIMUM ARC APPROXIMATION OF COMPLEX PLANE CURVES

Arc approximation method is widely used in machining those parts contoured by various complex plane curves. In this paper, several arc approximation methods are reviewed, and the algorithm of the optimum arc approximation, which ensures the continuity of derivatives, is established. The algorithm presented can be used to precisely machine the parts with complex plane curves and the revolving body with a curved surace. In addition, it can also be used in part-programming of CNC machining.     

Application of Multidimensional Scaling in the Analysis of Spatial Ground Motion

In order to search for a tool to test whether the earthquakes is reasonable for the design, a method based on multidimensional scaling (MDS) and the dynamic time warping distance (DTW) was proposed, which represents the dissimilarities of earthquake in a low dimensional space in a visualized way and uncovers hidden structure of earthquake. The analysis of record from the seismic array shows that the proposed method can be a powerful tool in detecting the correlation structure of spatial ground motion as well as verifying whether the algorithm is producing properly correlated motions in space.     

The Geometric precision and Performance Analysis for machining Surface based on Fractals

A new analysis method for machining surface profile error is presented in this paper.The linear regression and nonlinear regression are first applied respectively,and then the Weierstrass Mandebrot fractal function is used to obtain the fractal parameters of machining profiles.A minimal parameter set which depicts the machining surface geometric precision is set up,and the surface profile can be reconstructed using these parameters,and an analysis method for part performance and its tolerance structure is proposed.Examples are provided to illustrate the method is feasible and effective.     

Constant Scallop-height tool-path Planning for Surface Interpolation and the Evaluation of Errors

The calculative precision of the cutting breadth has a significant effect on the machining precision and the machining efficiency for free-form surface machining. For traditional arithmetic, there are two oppositional approaches to calculate the path interval. One approach is very simple, but its veracity is not enough for complex surface. The other approach is very complicated, so its calculative efficiency is low. A new approach is presented to calculate the path interval. A spline of circle is adopted to approach the transversal of surface. Then the arithmetic based on the spline is proposed to calculate the path interval. In the proposed methodology, the calculative efficiency is fully improved on the condition of meeting the need of machining precision. Furthermore, the algorithm''s time needed by calculating path interval is steady. So it is suitable for periodic interpolation. Two study cases verify the applicability of this new approach of Constant Scallop-height tool-path planning.     

Three Dimensional Eddy-current Field computation by Edge Finite Element Method of Mixed Elements

The edge finite element interpolation function of 1-forms for prism is derived.The electrical field intensity is used as the unknown variable.If the tangential component of electrical field intensity is an enforcing condition on the interface of eddy-current region and non-eddycurrent region,the tangential component of magnetic field intensity is a natural continuous condition.At last,the mixed elements of prism and hexahedron are used to compute a three dimensional eddy-current problem.     

ERRORS AND COMPENSATION OF FORM CUTTING HELICAL

A method which uses computer to model the form cutting of helical is presented and quantitatively analysed the errors of the ptofile shape and its position from the deviations of manufacturing and installing of the forming cutter and helical movement of the machine tools are quantitatively analysed, the optimum technique is used to revise the adjustable parameters for compensating the error. It is valuable in engineering application.     

Improvement of TSP and Application to Oriented Path Optimization for PCB NC Machining

The fast developments of electrical information industry bring electrical manufacture technology the rigorous challenges and the drastic market competitions. This text aiming at the problem, which is instantly solved in the PCB hole sit machining, proposes an oriented path optimized technology for PCB hole sit machining. And the technology uses Greedy algorithm and Ant System Algorithm to solve the problems that more holes and empty runs make machining time longer. The actual applied effect is better and machining efficiency increases 23.9%. Obtain good economic performance.