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Based on the taking sample by geological drilling, combined with the fractal principle, analysis on the cracked backfill particle size of its fractal features and strength correlation. Even each backfill sand specimen particle size is difference, but calculation data shows that the particle size of each sand specimen has preferable fractal feature, the sand specimen particle size distribution has remarkable fractal structure by the linear fitted results of the sand specimens. The fractal relationship of strength and particle size distribution shows that with the increased of fractal dimension, the strength of backfill is decreased, that is to say there is negative correlation, the main cause is that the higher parameter D of the fractal dimension, the higher fine-grained content and more non-uniform of the particle size distribution, especially for the thinner full tailings, if properly increasing the content of slightly crude particles, the strength of backfill will be certainly improved to some extent.

Optical glass is widely used as the most important material in optical field in recent years. Glass molding press (GMP) has been employed as a promising technique to manufacture optical components in mass production. Heating time and annealing time are the key factors which influence the production cycle. In this paper, an effective method of improving the heating or the annealing effectiveness is to increase the area exposed to the cooling or hot nitrogen by means of adding slots. In the same condition, four models with different slots were built. Based on the theoretical analysis of glass heating and annealing property in the molding process, finite element simulation was carried out. The results showed that the model with slots may decrease the heating and annealing time.

Glass molding is a high-volume fabrication method for producing optical components. Non-isothermal glass molding press (NGM) was proposed to fabricate optical glass, and its characteristics were studied by finite element method (FEM) simulation. The coupled thermo-mechanical analysis was carried out to analyze the key factors such as temperature distribution, stress distribution and strain distribution. The non-isothermal and isothermal glass molding (IGM) was studied, and optimal temperature match between glass and mold was obtained.

Glass forming process is a high-volume fabrication method for producing glass containers. In this paper, the mechanisms of glass forming process were analyzed. Combined the coupled thermo-mechanical analysis with the finite element method (FEM) simulation, it was carried out to analyze the key process factors such as forming temperature, forming pressure, friction coefficient. The results show that forming pressure has the greatest influence on the stress.

Glass lens molding is a high-volume fabrication method for producing optical components. In this paper, combined with the orthogonal test method and finite element method (FEM) simulation, the coupled thermo-mechanical analysis was carried out to analyze the key process factors. In order to reduce the testing time, an orthogonal test with three sets of level factors and three parameters is conducted to obtain the optimal molding process parameters. The result shows that the most significant parameter is molding velocity, the other effect parameters are molding temperature and friction coefficient. According to the previous analysis of orthogonal experiment, it is shown that the best optimal finishing process parameters were A2B1C1.

Car camera lens is widely used for the safety system of all kinds of vehicles. The car lens should have very wide field angle, strong ability to endure vibration and thermo-mechanical instability as well as erosion. According to these requirements, a new car lens is designed based on the aspheric glass lenses. The whole structure of car lens contains six separated glass lenses including two aspheric lenses. To reduce the cost, the aspheric lenses are made from low-Tg glass which is adaptable for mass production by glass molding press. The total track of lens is less than 30mm. For the enhancement of night vision, the F-number is set to be 2.4. The full FOV (field of view) of 160 is wide enough to capture all the dangerous information around the car. The imaging resolution is designed to be 3 Mega pixels. The designed result proves that the new car lens features high imaging quality. Its MTF (modulation transfer function) value is not less than 0.15 at the Nyquist frequency as for the field angle of 160. At the half Nyquist frequency, the MTF values of the most field angles are not less than 0.5. Therefore, the new lens could be used in the front of car to monitoring the dangerous cases around the corner.

According to the actual state of the 1150 horizontal main haulageway of Tailai colliery is in the affected areas of many faults, both on the roof to floor and two sides convergences are about 1000mm,the YTJ20 strata structure detector was used to detect the strata structure character of the roadway roof, it showed the surrounding rock of 1150 horizontal main haulageway is very broken and the maximum failure depth reached to 6m; meanwhile we took 4 group of rock samples from the broken zone to carry out x diffraction, the results showed that the surrounding rock in the broken contained high expansibility rock, so measure of rock surrounding grouting reinforcement was proposed without changing the original supporting parameters. Comparative analysis of rock surrounding reinforcement effect before and after grouting was calculated by FLAC simulation soft. The result shows only supported “bolts + shotcrete layer + cables”, both the deformation speed and deformation amount are very obviously, the community of “rock-support” shows loose and breaking state; But using the combined supporting method of grouting reinforcement and “bolts + shotcrete layer + cables”, the surrounding rock deformation obtained effectively control with less stress release, the community of “rock-support” shows higher integrity degree, It can ensure the safe use of the roadway.

A compensation method was proposed for correcting wheel setting error and residual form error in nanogrinding of axisymmetric surfaces. In this method, profile data from on-machine measurement were used to obtain the setting error of grinding wheel, as well as the normal residual form error. Compensation model of single-point inclined-axis grinding was built up for generating new compensation path. Grinding test of aspheric tungsten carbide mould was conducted to evaluate performances of the compensation method. A profile error of 182 nm (peak to valley) and average surface roughness of 1.71 nm were achieved. These results indicated that the form error compensation method may significantly improve form accuracy of ground surface.

Optical glass is widely used as the most important basic material in optical field. In this paper, four different shape finishing tools are designed for polishing flat K9 glass by using magneto-rheological finishing process. Influences of the finishing tool’s shape on surface roughness are investigated and analyzed under different related parameters such as finishing time, rotational speed of tool and finishing gap. The result shows that the slotted tool could obtain better surface roughness than the non-slotted tool under the same conditions. Through changing the magnetic field intensity, finishing gap, rotational speed of tool and finishing time, an orthogonal experiment is conducted to obtain the optimal finishing process parameters.

The present authors proposed a new centerless grinding technique for the fabrication of microscale pin-shaped parts. The new technique uses an ultrasonic vibration shoe whose structure and dimensions was determined in detail by FEM analysis instead of a regulating wheel as in conventional centerless grinding. The workpiece is supported by the end face of the shoe and the blade, and the rotational motion is controlled by the micro elliptic motion generated on the end face of the shoe. a shoe was made and installed on an existing centerless grinder to perform actual microscale centreless grinding operations involving a tungsten carbide pin-shaped workpiece 0.6 mm in diameter and 15mm in length. The experimental result gave a microscale workpiece 75μm in diameter and 15 mm in length.

This paper reported an experimental study on ultra-precision grinding for micro aspherical lens mould. One-point grinding mode and inclined axis grinding mode are employed and investigated in grinding process. Grinding test of a micro-lens mould using form error compensation technique is conducted. The experimental results show that ground micro aspheric mould surfaces with form (PV) around 0.122 µm and a roughness (Ra) less than 2 nm is achieved successfully.

The lens molding technology has become a promising fabrication method for glass lens, especially for aspheric glass lens in batch. Because during the real compression molding, the error compensation for mold shape turns very difficult, the mold needs to be repaired repeatedly to meet the requirements of lens molding. To solve this problem, a cooperative design scheme is proposed. However, the scheme is not limited to solving the mold repairing; it also aims to providing the integrated and optimal design for aspheric glass-lens mold. In fact, the cooperative scheme is a collaborative software platform, which integrates with data processing, optical design, finite element analysis, error compensation and mechanical design for lens molding. On this platform, users only need to submit the (camera) lens parameters or measured data of aspheric lens, and then the platform can provide the final mold drawings, which will be input in the CNC software of ultra-precision machine and guide the mold fabrication. Meanwhile, the cooperative platform is Network-based PDM system, so designers could remotely communicate with it and help to finish the mold design jointly. In this case, the cooperative design could tremendously improve the efficiency and accuracy of lens molding.

In this paper, a new method of improving uniformity of surface roughness through controlling feed rate was proposed. A CNC grinding software based on feed rate controlling and error compensation for aspheric surface was developed. The structure and function of the software system was described. An experimental test for grinding aspheric surface of WC mould was conducted for evaluating the performance of the compensation process by using this developed software. After compensation grinding for several times, form accuracy of PV 126 nm, roughness of Ra 3.4 nm can be obtained.

This paper clarifies the influence of the geometrical arrangement of the workpiece on workpiece roundness in the ultrasonic elliptic-vibration shoe centerless grinding, and determines an optimum geometrical arrangement for minimizing the roundness error of the workpiece. The influences of the geometrical arrangements of the workpiece on workpiece roundness were investigated by computer simulation and practical grinding operations involving pin shaped workpieces. The experimental results agreed closely with those obtained by the simulation, the results of simulation and grinding tests indicated that the final roundness error of the workpiece after grinding reaches a minimum at a particular angle number (= + =7) for various values of the blade angle.

This paper reports a study on oxide film formation mechanism in electrodeless ELID grinding. The formation mechanism of oxide film was analyzed based on electrochemical principles, its formation model was built and the growth process was also simulated. The simulation results showed that the oxide film thickness h and its growth rate g are nonlinear functions of time t, voltage and duty cycle are important factors which take effect on g and h, and the electrodeless ELID grinding is a process of weak electrolysis and suitable to use micro wheel.

This paper reports a systematic investigation of high speed grinding of hard-to-machining of titanium alloys. The ground surfaces were characterized using scanning electron microscopy, and the effects of different grinding parameters on roughness were discussed. A numerical model was established to predict surface roughness based on the evolutionary neural network optimized by Genetic Algorithm (GA). The modeled results were in good agreement with the experimental results.

This paper investigates the effect of horizontal vibration assistance on surface roughness in magnetic abrasive finishing, and the material removal mechanism associated. The experiments on vibration-assisted finishing have clearly indicated that the improvement of surface roughness is mainly attributed to the cross-cutting effect of abrasives.

ELID (electrolytic in-process dressing) grinding was proposed by one of the authors for automatic dressing the grinding wheel while performing grinding for a long time. It offers a high effective way and has been widely used for grinding hard and brittle optical materials. However, those surfaces produced by fixed abrasive grinding are characterized by considerable sub-surface damage, micro-crack. Magneto-rheological finishing (MRF) is a novel precision finishing process for deterministic form correction and polishing of optical materials by utilizing magneto-rheological fluid. In this paper, an ultra-precision synergistic finishing process integrated MRF and ELID grinding is proposed for shorten total finishing time and improve finishing quality. A lot of nano-precision experiments have been carried out to grind and finish some optical materials such as silicon, silicon carbide, etc. ELID grinding is employed to obtain high efficiency and high surface quality, and then, MRF is employed to improve further surface roughness and form accuracy. In general, form accuracy of ~ λ/20 nm peak-to-valley (P-V) and surface roughness less than 10 Angstrom are produced in high efficiency.

This paper proposed a viewpoint to explain why vibration assistance may increase material removal rate (MRR) in vibration-assisted magnetic abrasive finishing process. A series of experiments on vibration-assisted finishing have been carried out. On the basis of these experiments, the finishing characteristics are represented summarily. It was shown that the increase in material rate is mainly due to an increase in material removal per unit working distance.

Conventional stability analysis of slopes is established on vertical slices with a linear Mohr-Coulomb (MC) failure criterion. In this paper, the soil mass of slopes is assumed to follow linear and nonlinear failure criteria. A new procedure is proposed for determination of stability factors of slopes using triangular slices within the framework of limit analysis method under plane strain condition. The potential sliding mass is divided into a series of triangular slices, rather than vertical slices as usual. Using a generalized tangential technique, the nonlinear failure criterion is simplified as a set of straight lines according to the linear MC failure criterion. The straight line is tangential to the curve of the nonlinear failure criterion. With a linear MC failure criterion, solutions to stability factors are determined by limit analysis theory, which agree well with the published solutions. With triangular slices method, a study is carried out to investigate the influences of nonlinear parameter on stability of the soil slope.