Parameter Design for Machining Quenched Internal Helical Gears by EDM

Aiming at the problem of machining quenched internal helical gears, a method and its equipment are discussed and designed, which is used for machining quenched internal helical gears by EDM. Its characteristic and principle are proposed. The modifying design of the electrode gear and the calculating method of its modification coefficients is presented. Analyzing for the error of the machining equipment is done. The results show that this problem can be solved by EDM, the electrode gear is the modification gear of machined gear and the machining accuracy can be improved by controlling errors.     

Product ontology screening and its application in variant design

A product ontology screening method which can be used in variant design is proposed. With the support of complete ontology view of product resources, the product functional requirement and structural characteristics are converted to demand constraints, which are used to screen product ontology. For different screening hierarchies and objects, different screening rules such as pattern matching, case matching combined with manual decision and auto matching on the basis of case-based reasoning are adopted. The semi-automatic screening method with human-computer cooperation has impressive effectiveness on the improvements of the accuracy of design schemes and the flexibility and efficiency of design process. Finally, a variant design supporting system for building door and window is developed, which proves the feasibility and effectiveness of the method.     

正交试验设计中正交表的特点及正交的意义浅析

通过正交试验设计可以大大减少试验次数,得到不同因素水平的最优组合,从而确定合理的试验方案及工艺条件等,因此在科学研究中应用非常广泛。为了更深入地理解正交试验设计方法,以表和图的形式对正交试验设计的特点进行了详细分析;对正交性的意义、体现从向量信息不相关及向量内积计算的角度进行详细的分析及解释,以期为广大师生的学习及应用提供一定的帮助。     

Optimum Design of Individual Foundation and Its Application

On the basis of analysing the defaults occuring in normal design,a new method of optimum design for individual foundation is put forward in this paper.This method can solve some problems successfully such as the strengh and deformation can be considered at the same time,which cannot be done in the current specification.The optimal mathematical models of individual foundation design and the bottom surface dimension design under eccentric load are derived.The optimal solution is decided by method of optimization and the method selected is penalty function and complex method, and the programs of optimum algorithm have been compiled and design and drawing of individual foundation have been completed. The final result suggests that a fair-sized economic efficiency can be obtained by using optimum method for foundation design.     

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.     

Optimization of Structure Parameters in Ultra-precision Plane Honing

The structure parameters of honing wheel have effects on machining accuracy in ultra-precision plane honing. This paper put forward to the optimization of structure parameters. By calculating the machining accuracy coefficient and wear coefficient of triangle radial structure honing wheels, it is obvious that the suitable triangle radial structure honing wheel can improve machining accuracy of workpiece.     

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.     

A Practicable Engineering Algorithm ofParallel Machining System

Parallel machining system is a kind of typical production environment.Its scheduling algorithm has Np_Completeness if E/T is optimal criterion.In this paper,an advanced heuristic algorithm is developed.The new algorithm's property lies in simplified computation,low complexity and easy programming.It has been shown that the heuristicalgorithm can be used in engineering.     

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.     

Estimation of Earth Work Volume and Design Elevation in Large Earth Work

In this paper,the approximation calculation method based on calculation model of earthwork formula of tetragonal prism is described. The optimization design elevation in large earthwork can be determined by this method. Through introducing a set of different design elevations, the difference between and sum of the total excavation and the total fill can be calculated. An economical analysis is carried out on the design elevation chosen with little value for both cases by numerical values comparison. The elevation with the lowest cost is taken as the optimal design elevation.     

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.     

The Internal Force Calculation of the Whole-Raising-Scaffold

Because of the different configurations of buildings to be constructed, the arrangement of the whole-raising-scaffold used for practical construction is not always the same, which results in difference of the internal force of the whole- raising-scaffold in application. Based on the abovementioned, in this paper, the design method of the whole-raising-scaffold is investigated, a mechanical model based on the three-span continuous beam is set up, the mechanical characteristics due to the action of various load of the whole-raising-scaffold under the worst working condition is analyzed. Then the calculating method for the internal force of its main structure can be found. Combining the internal force calculated by this method, the security of the scaffold can be verified. The method introduced by this paper can be used as a general method for the scaffold design.     

A Simulated Annealing Arithmetic Based on Uniform Design

Some ideas of uniform design in the test design are introduced into Simulated Annealing Arithmetic and a new method of design based on uniform design is discussed. The global optimal solutions of nonlinear multi-peak function can be found by this method. A series of uniformly distributed points are generated by the principle of the uniform design in variable design space. These points are regarded as a series of start points of the optimization model. The Simulated Annealing Arithmetic is chosen to compute and a series of local minimum values can be gained. Before compared with each other, the best value of all local minimum values can be found out, the value is thought as the global minimum in some degree. According to the method, a program is compiled and an example of design is implemented. The result of the example testifies that the method is feasible.     

Study on A New Type of Soft Wheel for High Efficiency Grinding

The paper describes the design of high efficiency soft throw away wheel whose tension of abrasive belt is adjustable.With the airbag internal capsule and continuous spring ring structure,grinding vibration is decreased and machining accuracy is improved.     

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.     

用亚洲玉米螟测定苏芸金杆菌制剂毒力效价的研究

利用亚洲玉米螟对苏芸金杆菌的毒力效价进行了测定.供试虫以玉米螟二龄幼虫为佳.用候选苏芸金杆菌制剂与半人工混合饲料混合接虫感染的方法作毒力效价测定,结果准确,操作方便,完成一次测定需时三天,标准差为15.49%.     

Analysis on Three -Dimensional Numerical Controlled Last Machining Algorithm

On the basis of applying three dimensional discrete formative technology to describing last surface, working principle of numerical controlled last carving machine is briefly introduced. Then the algorithm of ascertaining milling cutter machining position during the machining process is analyzed in detail. We establish a three dimensional reference frame with spatial analytic geometry and obtain the spatial equation of milling cutter rotary surface. According to last machining character, we put forward a machining algorithm named Minimal Distance Method and is used to calculate the milling cutter machining position. Finally, the glabrous degree of last made by us has reached the conventional demand.     

Accurate mathematical models for relief grinding of gear hob cutters

A mathematical model for accurate relief grinding of gear hob cutters along radial directions is presented based on the analysis of grinding geometry. Both the design and manufacturing models of gear hob cutters are carefully derived and presented. By employing the plane envelope theory, the reference contour of the grinding wheel is determined in order to attain the design tool profile precisely. The tooth profile error model after regrinding is also given to confirm the grinding parameters. The model provides accurate solutions for both the tool profile and the sectional contour of the grinding wheel. It is simple and straightforward and can be used to produce high precision hob cutters systematically. Two numerical examples are presented to illustrate the effectiveness of the proposed method. The model computing results indicate that the proposed method is practical, precise and reliable. The method provides valuable reference for the design and machining of hob cutters.     

Application of Error Compensation Methods in High Precision Machining of Globoid Worm

鲜食葡萄始终占主导地位是我国葡萄产业发展的一个突出特点.长期以来,我国鲜食葡萄贮运保鲜业一直比较滞后,基本是季产季销,地产地销.因此,我国鲜食葡萄集中产区经常出现采后"运不出、贮不进、销不掉"的被动局面,阻碍了鲜食葡萄产业在适宜栽植区的快速发展.一些非适宜产区为了填补当地鲜食葡萄市场空白,也在积极发展鲜食葡萄生产,其结果必然导致生产成本提高,不利于我国鲜食葡萄的区域化种植和商品化生产基地的建设.     

Research on Error Automatic Revised Method of LSI Wafer Honing Process

A new automatic revised method of wafer profile error which uses CCD measuring error,sets up machining data base and carries out a wedge structure for stepless compensating error in honing process is described.Using this technology,a high precision LSI wafers can be obtained.