Advanced Materials Research Vols. 102-104

Abstract: As far as the controllability of turbulence flow field surface effect of the soft abrasive flow was concerned, to begin with the analysis of the motion of the particle in the flow field, the paper studied the motion law of particle in the flow field, especially in the boundary layer. Based on the fluid-solid two-phase flow coupling style, it established the single particle dynamics model. Then it established the realizable k-ε model, in the light of the numerical simulation of turbulent flow. With the adoption of the computational method of SIMPLEC, it asked for the velocity and the pressure of fluid in the U-shaped flow passage, the velocity and the motion law of particles with different granularities and velocity, in the boundary layer. Experimentation results tell us that the original velocity plays a leading role in the motion trajectory of particles. The diameter influenced the particles motion trajectory in some degree.

Abstract: The development and manufacturing speed of products have become the focus of competition, at the same time the manufacturing not only has to meet user’s constantly changing needs, but also has to have a relatively strong flexibility of manufacturing technologies. Additive processes can be defined as rapid prototyping, which generate parts (prototyping) in a layered way, is gaining progress by rapid tools (RT) and rapid manufacturing (RM) for production of functional parts in small quantity and even one product without adding the cost becomes more and more critical. The paper describes which mechanism of stereo lithography (SLA) rapid prototyping can be applied to rapid tooling for production complex geometries for long-term consistency. Moreover, the paper demonstrates the application examples of rapid tooling fulfilling the required physical, mechanical and geometrical properties in precision deformation and casting process. The most notable advantage is the integration of production design and digital manufacturing within the product development period.

Abstract: Modern cold extrusion technology has been from a traditional method developing into compound extrusion, multi-action extrusion, closed forming, divided flow extrusion and flow control forming as well as other forms. In this paper, basic principles of floating die extrusion and divided flow extrusion were analyzed. Tests and experimental practice and application of floating die and divided flow extrusion of gear were stated. Spur gear forming in application and forming processes based on exchange mandrel was detailed.

Abstract: Effect of lapping speed, plate material and crystal orientation on material removal rate and surface roughness were investigated by experiments and Taguchi Methods. Experimental results show both materials remove rate and surface roughness could be finished by using sythetic copper lapping plate with w3.5 cubic boron nitride abrasive than that for thin plate. Materials removal rate and surface roughness have no much difference for different crystal orientation as A-plane, C-plane and M-plane with experimental parameter conditions, lapping speed would be recommonded to not over 40rpm.

Abstract: The surface roughness of the hydraulic prop had an important effect on the wear resistance, fatigue strength and property of fit. The ultrasonic surface rolling extrusion (USRE) processing experiment was employed to improve the surface roughness of the hydraulic prop, some machine parameters such as the tools transfer magnitude, feed were studied in detail, the contact style roughness tester( Mahr S2) was used to test the surface roughness of the workpiece. The experiment results showed that the USRE could improve the surface roughness evidently, the Ra value from 0.976μm reduce to 0.105 μm by one-hit machining. The feed was linear with the surface roughness, and when the tools’ amplitude was 6.5~8.5, there were a better surface roughness Ra 0.090μm. USRE processing the surface time and again could improve the surface state.

Abstract: A manufacturing technology applying a special spiral-fluted electrode in traditional ECM (Electro-chemical Machining) is introduced, this method is provided with the advantages of both narrow-gap ECM and pulsed current ECM. It is a new technological method for expanding holes in hard metal materials parts. In this paper, a new type ECM electrode is proposed to solve hole expanding problem in carbide drill bush. The machining principles and the influence of some operating parameters of ECM on the machining precision and productivity are described. Experiments results indicate that the accuracy and quality of the machined surface and the machining efficiency could be improved greatly by applying spiral-fluted electrode in ECM. It is also showed that the inner surface of the carbide bush was finished easily by this method with the optimal operating parameters, at the same time, the surface roughness of a machined hole is improved to 1ess than 0.2m Ra, and the dimensional accuracy of hole can reach 0.02mm.

Abstract: In this article, we propose a tool wear image segmentation algorithm based on Markov Random Field model. In this algorithm, the wear area was divided into wear area, background area and body area, in terms of the MAP (maximum a posteriori) criterion, and we got the pre-segmentation image. Afterwards, the aiming area (region B) was segmented out from the wear area by using peak-band algorithm and the edges are integrated in mathematical morphology theorem. As a result, we obtained an integrated tool wear region. Experiments indicate that the segmentation algorithm can be used to evaluate the degree of tool wear and applied to synchronously monitor tool wear condition effectively.

Abstract: Performance-based parametric design method for improving the face milling cutter design efficiency and ensuring the use of performance has an important significance. Three kinds of parameter design method are described in this paper, and parametric design of series of layer milling cutter is completed by modeling parametric design method with UG software. Also, modal analysis is made with FEM. Therefore the study results provide examples for optimization of tool structural and analysis of restrain vibration.

Abstract: A methodology based on relax-type wavelet network was proposed for predicting surface roughness. After the influencing factors of roughness model were analyzed and the modified wavelet pack algorithm for signal filtering was discussed, the structure of artificial network for prediction was developed. The real-time forecast on line was achieved by the nonlinear mapping and learning mechanism in Elman algorithm based on the vibration acceleration and cutting parameters. The weights in network were optimized using genetic algorithm before back-propagation algorithm to reduce learning time.The validation of this methodology is carried out for turning aluminum and steel in the experiments and its prediction error is measured less than 3%.

Abstract: Based on the kinematics analysis and the cutting depth calculation of single abrasive grit, the mathematics models of the cutting deforming force and the average cutting deforming force were made by introducing the unit grinding force, Fu. And the formula of the average cutting force during the grinding zone was calculated. The experiments on the grinding force ratio were conducted under conventional grinding(CG) mode and normal ultrasonic vibration assisted grinding(NUAG) mode. The results showed that the unit grinding force in NUAG was lower than that in CG under the same machining condition; the grinding force ration was decreased due to the normal ultrasonic vibration of the workpiece. And it was helpful to improve the machinablity of the hard-brittle material.