In quality engineering there are three important subjects which are computer-aided integrated tolerancing, design for quality, and dynamic quality control of small-batch production. Their value and state-of-the-art were introduced. Their key technology, future research, and hot spot were analyzed.

In order to overcome superheating and burning loss of rolling bearings , several methods of selecting rolling bearing fit are discussed , and on the basis of practice experience , the proposal on selecting fit is put forward.

A new quality-oriented statistical tolerance and the representation of statistical tolerance zone are discussed on the basis of statistical dimensional tolerance standards of Germany and China as well as the exist ing representations of statistical tolerance zone. It is pointed that the new quality-oriented statistical tolerance technique and developed quality indices system, data bases and the standardized charts of statist ical tolerance zones have widely application value as it established a standardized interface among specifications, quality requirements and statistical quality control.

Some methods about fractal-based tolerancing are discussed in this paper. The engineering calculation on profile fractal dimension is presented in detail.

This paper elaborates on the change of conjugat ion tolerance caused by the real measurement error of part machined previously and the effect on conjugation quality of the conjugative part coming with jumbo size and the main origins of measurement error. And it also depicts the computational methods to conjugate tolerance and the potentiality that tolerance exceeds the fixed value in single or small volume product ion. Finally , in order to guarantee conjugate quality , it submit s the measure that should be taken in the cause of designing deployment and measuring the real dimension.

Relative requirement is a tolerancing method of boundary control. It gives the maximum material boundary or the least material boundary and the comprehensive tolerance to satisfy the requirement of assembly or strength, and can obtain the higher economic benefit in manufacturing . It should be applied in tolerancing positively.

Generat ing dimension chain is one of the components of computer-aided tolerance design based on assembly which also includes three other components, tolerance representation, tolerance analysis and tolerance synthesis. It is the base of tolerance analysis and tolerance synthesis. The algorithm of generating assembly dimension chain automat ically based on entity-relationship model and a new algorithm in 1D based on searching direction which can generate mating relation graph are proposed. In the new algorithms, the option of the direct ion of relation is added in order to reduce the complexity of mating relation graph. In addition, the algorithms can distinguish the redundancy in relations.

The feature ex pert system w hich services tolerance analysis and tolerance synthesis is int roduced.Applying it to design environment , the system supports tolerance design commendably . Finally,an example is given.

The optimal allocat ion of geometric tolerance values is represented as the combinatorial optimization problem, and Genetic Algorithm ( GA) is applied to solve the problem. The generation of geometric error accumulation function is analyzed, and the establishment of machining cost??geometric tolerance model is studied. According to the propert ies of this opt imization problem, coding , fitness and genetic operators are formulated. A gear pump example is illustrated to show the optimal allocation scheme to be effective.

This paper analyzed floating model, Virtual Boundary Requirement s ( VBRs) , Conditional Tolerances( CTs) and based on rules of ISO and national standards, and present some mathematically equivalent formulas for consistence test of slab and slot, designated as soft gauge. It provides theoretical
basis for evaluation of computer-aided tolerance design in Parametric CAD System based on constraint and facilitates the integration of CAD/ CAM. All in all, it has significant values in science and practice.

This paper presented a way based on CAD softw are to analyze assembling dimension chains automatically. And the corresponding software has been developed, applied in actual analysis of assembling dimension chains successfully.

At early stage of the product design, the required funct ional assembly tolerances are f irst allocated to the related component dimensions. Then these dimensions are represented as the process dimensions.Using process tolerance chains, the required funct ional assembly tolerances are direct ly represented as the process tolerances. Through formulating and solving the optimization model, the concurrent design of process tolerances can be made. Finally a practical example is given.

This paper adopted hypergraph to represent const raint-graph, and geometric reasoning was used to solve constraints, meanwhile, the computing of geometricentities was based on feature points.This method can realize parametric design with multi-constraint driven ( such as area constraint) . It is
proved to be efficient and has been used as a tool for parametric design in AutoCAD.

Geomet ry precision of gear designed by aux iliary computer has accelerated the design process and improved the design quality, instead of the convent ional w ay of ex perienced design and artificial re-trieving by the method of the theory design and opt imal design. The softw are, resolving the problem of contact of Visual Basic and data bank successfully, accomplishing mutual data conveying, make it bat ter in ability of t ransplantat ion and ex pandat ion by modularity design.

On the basis of founding the relat ionship of tolerance cost , the opt imal design method of mechanical product's tolerances raised at least manufacture cost, and carring on an example. By this method, the notable economic benef it s can be obtained at large quant it ies of production.

With the development of Computer Aided Quality Control System, sig nificance test , as a necessary tool of quality management and quality control, is faced w ith the problem of program. In order to solve the problem, this paper analyzes the key methods of sig nificance test program and brings forward one method w hich adopt s numerical integrat ion and advanced & retreat method and dichotomy numerical methods to solve it . The F test , as a typical method of significance test, w as analyzed and programmed concretely. At last, satisfactory solut ion w as obtained throug h the test and verif icat ion of some examples.

The principal problem is that quality needs are transferred correctly, i. e. quality conversion equally in design for quality. The principle and model of quality conversion is discussed. The needs of customers are analyzed, reasoned and transformed by the theory of fuzzy set .

This paper introduces a new method for collect machining quality data. The device is a kind of portable electronic instrument . Through robust statistics, put forward a robust estimation algorithm to estimate measuring results and error. This paper applies fuzzy subset theory puts forw ard a new fuzzy logic controller and accomplish machining quality fuzzy automatic control.

The process and characteristic of group evaluation about design quality were studied. The description model of design evaluation was set forth. Then the possible used methods in each step were analyzed.The mapping from design variable space to performance variable space and from performance variable space to preference space, as well as the negotiat ion and trade-off during mapping w ere especially studied. At last the satisfied alternative was chosen.

The disadvantages of the present geometric tolerance theory and the associated standards are analysed systemat ically, and the stat istical tolerance concept is proposed. The characteristics of the statistical tolerance system are clearly ident ified as being advantageous. In the analysis, w e clearly point out that the stat istical tolerance means the tolerance of statist ical parameters, and the stat ist ical tolerance system w ill be the development direction after the geometric tolerance theory. The development of the process for surface roughness evaluat ion is used as an example to illust rate the finding s for the statistical tolerance.

This paper deals with the inference for uncertainty of precision instrument. It offers a suggestion on the inference. It also raises some questions about the data processing of the precision measurement introduced in some books on measurement technology.

The mathemat ical models of evaluat ing prof ile error of any surface take by CMMS are proposed, these methods has been proved fitting for the geometrical tolerances standard by using optimization edited in Turbo C.

A method of synchronous testing for long travel multi-cylinder is proposed in this paper. The new method with computer realizes real time detecting. It is proved in practice that the method is direct and reliable. It will have remarkable technical and economical value and broad application future.

On the basis of experience w ith measurement this paper discusses the concent ricity and roundness error measurements by three-coordinates measuring machine from the viewpoint of the author.

A high precise and effective measurement system of axis-straightness error of long-shaft based on virtual instrument interface is discussed in this paper.

The developments of coordinate measurement machine ( CMM ) and computer technology have raised new challenges in measurement, descript ion and mathemat ical def init ion etc. of tolerance.This paper at tempted to put forw ard the constant value principle based on the hypothesis of cont inuity of solid body in mechanics of materials; and stated the method of realizing the unity of dimensional tolerance, form tolerance and position tolerance etc. Through obtaining the ideal form feature of actual feature in the light of the constant value principle, and g et ting the tolerance zone which is convenient for its computer description based on the similar sw ee-l shrink of ideal form feature, as w ell as achieving the correct mathemat ical description of the tolerance zone through the t ranslation and rotation of coordinate axis. At last , some valuable conclusions in use are obtained in the evaluation of roundness tolerance according to them.

A novel method using grey theory to characterize the measurement uncertainty is proposed.The method permits an accurate est imat ion of the uncertainty under the condit ions that the measurement number is small and the probability distribut ion unclear. The feasibility of the method is validated by pract ical examples.

Because of the error in the measurement, there are misacceptance and misabandonment to the workpiece. The former impairs the quality of the part s, while the latter makes the production uneconomical. It is vital to cont rol both of them in a g iven limited area. By w ay of the analyzing the Taylor expanded formula of Loss function, we know that the loss of the quality or cost L ( x ) caused by measurement error is a funct ion of mean square α＾２. This paper gives an opinion on the calculating of the value of k in the equat ion Ｌ（ｘ）= ｋα＾２, which is not the same w ith Mr. Takuchi, who is a famous Japanese scient ist . Another aim of the paper is to compare the dif ferent measuring methods through the loss function and the cost accounting .

The measurement principle and method of run-out error by laser are int roduced, and error is analyzed. It indicates that the property of this method is realized simply and easily and has reliable measurement results and hig her measurement precision etc. It is applied to not only the practical measurement in lab and manufacture, but also providing reliable basis to the design and manufacture of the runout measurement device by laser.

Over the past eig ht years the subject of 3D surface met rology has developed from something of a novelty to a posit ion where it has now become a crucial tool in the characterisat ion of engineering surfaces across a broad rang e of applicat ions. It is widely accepted that the nature of the topography of a surface has a signif icant influence on the efficiency and functional performance of the surface include wear, frict ion, lubrication, corrosion, fatigue, coat ing, paintability , etc. It is also increasingly being recognised that in order to fully study and control surface manufacture to enhance the above applicat ions, studies need to be carried out from a 3D perspect ive. A number of key research groups have been working in this area in an effort to produce def init ive 3D surface roughness standards. This paper reviews the most recent work in the field of 3D surface characterisat ion and out lines the development tow ards a 3D surface roughness standard.

The act ive measurement instrument is developing tow ard the intellectual and multi-parameter measurement. T he measured signal is delayed by sensors, and it is also the main reason of dynamic errors.T he paper int roduces a method of integrated to process and cont rol intellectually for information
measured variable by sensors. The effects of the time consistent Tm delayed by sensor is compensated or corrected in measuring by. The delayed Tm can be diminished or eliminated. The information by sensors is being processed and cont rolled in measuring. It w ill be a method of measurement intellectually and automatically.

A new type of intelligent water meter is introduced in this paper. It s software and hardware implementation is given as well.

On the basis of introduct ion of the machine tool for pressing oil-bearings, a neural net model is established to develop a symbolized measurement system of oil-bearing in this paper.

This paper provided a method of multiview establishment. According to the 3D data model,geomet ric const raints and projective const raints among views was established. By driving dimension, the paramet ric design of complex engineering drawings has been effectively realized.

An algorithm that can automatically identify actual situation of entity from 2D orthog raphic views according to the relations of chains are proposed.

The idea of "surface direct interpolation (SDI) ”is introduced according to the characteristic of machining polygon non-circular surface ,and an interative CNC interpolation pattern for processing the tool path of that is presented. The principle of tool path generation automatically and the algorithms of real time interpolation are studied deeply.

In order to fulfil Shape Changed Design of CAD , methods of CAPP are applied into CAD technology to satisfy the automatic design process requirement . This paper analogizes the Variant Approach with Shape Changed Design in detail. And a product classify code system is int roduces based on nearness theory , plan of feature code mechanism is also presented.

In mechanical design many parameters have to be considered. The dependencies of these parameters are usually very complex . In order to get good solutions, the designer has to work iterative and rely on his know-how . A method to get opt imal solutions without relying on the designer has know-how is the optimization with evolutionary algorithms.

To improve the efficiency of internal and ex ternal business process chains a cont inuous and complete dig ital product and product ion descript ion is necessary. Using the feature technology as the informat ional backbone the integ rat ion of product specification and product modeling, simultaneous cost predict ion, process and resource description is possible.

In this paper the vibrat ional characterist ics of the earth surface collided by a free-falling hammer are first analysed. The dynamic model is established and the displacement , velocity and acceleration of the vibrat ion system are obtained. The self-pow er spectrum of the vibration system are disccused by
using FFT.

By replacing of Gaussian filters in split spect rum processing using RAC filters, a new split spect rum processing technique is presented in this paper. High performance reliability and great SNR improving ability of this technique are testified by some practical results.