Materials Science Forum Vols. 471-472

Abstract: The effect of died-pressed binders, such as polyvinyl alcohol (PVA), butyl sodium rubber (BSR) and paraffin wax (PW), on green strength, green density, dimensional stability, residue, sintered compact density and mechanical properties of Ti(C,N)-based cermet was investigated. It was found that the types of the binder had a significant impact on the characteristics of the green compact. PVA improved dimensional stability of the green compact due to interaction between binder and particle. The glass transition temperature (Tg) of PVA influenced the forming behavior of Ti(C,N)-based cermet powders during died-pressed processing. Some residual moisture was needed to obtain high green strength. PVA had a gradual burnout with a low char residue in nitrogen. Compared with PVA, the influence of binders BSR and PW was also presented and discussed.

Abstract: In the present paper, the thrust cutting force model in ultrasonic elliptical vibration cutting is proposed based on the principle of ultrasonic elliptical vibration cutting, and the reason of the thrust cutting force reduced by applying ultrasonic elliptical vibration is clarified theoretically. The effect of ultrasonic elliptical vibration on the thrust cutting force is verified experimentally.

Abstract: The employment of ceramic material simulation design methods can eliminate the disadvantage of traditional ceramic material developing methods of being time-consuming, laborious and high cost. Three simulation methods of artificial neural network, regression analysis and pattern recognition, and their application to ceramic material simulation design were presented in this paper. The problems existing in ceramic material simulation were proposed finally.

Abstract: Aiming at the existent problems in the application of high efficiency grinding, some countermeasures are put forward to further exploit its potential, including the topography optimization design for high efficiency grinding wheel and cooling enhancement technology with jet impingement in grinding zone. The optimization model advanced here can be used to optimize the grinding wheel topography for different grinding processes with the minimum specific grinding energy. The cooling enhancement technology employed in creep feed deep grinding experiment of titanium alloy shows remarkable cooling capability. It is able to steadily control the temperature on workpiece surface at an extremely low lever under 100°C,when the workpiece is seriously burn with the conventional coolant supply. Further studies on the combination of these two countermeasures will not only enable us to increase the available material removal rate to a new lever but also solve the workpiece burn problem for those difficult-to-machining materials in high efficiency grinding.

Abstract: The purpose of this study is to develop a new kind of technology for the formation of an arbitrary gear tooth profile. In terms of spatial gear meshing theory, a universal transmission mathematical model for forming an arbitrary gear tooth profile has been constructed based on a standard involute gear hob. The coordinate relationship between an arbitrary point on hob cutting-edge curve and the generated point on workpiece has been deduced in detail. Hereby, an arbitrary gear tooth profile can be generated by means of computer flexible controlling each enveloped position on workpiece, and we do not need to spend so much money again to fabricate a special kind of gear cutting tool while cutting a special shape of gear tooth profile. So, this study has great economic importance, and has established the basis of generating an arbitrary gear tooth profile by means of an ordinary involute gear hob and a CNC (Computer Numerical Control) hobbing machine.

Abstract: The Mahalanobis distance feature proposed by P.C .Mahalanobis, an indian statistician. In this paper, we propose a new concept, Local Region Mahalanobis Distance feature –LRMD feature, we shall discuss the structure form, the obtaining methods of LRMD feature from an image and the relations between the LRMD feature and wearing and breakage states of cutting tools. The new research results indicate that the method of automatic on-line cutting tool condition monitoring based on LRMD feature can has better inspect result than the method of Mahalanobis Distance feature.

Abstract: A new type of non-chisel-edge shallow-drill is developed for machining high manganese steel, which is a typical hard-to-machine material. The marked characteristic of the drill is that the cutting edge is non-chisel-edge, consisting of a section of straight line and a part of curve nearby the center. The characteristics of machining performance of this drill are analyzed. Measures adopted in design for improving cutting performance and prolonging tool life are also presented. Applied example indicates that this new drill has good cutting performances and long life. Compared with common twist drill, the axial thrust cutting force of this tool is reduced 30~50 percent.

Abstract: In this paper, an experimental study was carried out to fabricate a new kind of ultra-fine diamond abrasive tools by means of sol-gel. The physical properties of the new diamond abrasive tools were evaluated in terms of the bulk density and hardness. The ultra-fine diamond tools were then used to polish granite on a vertical spindle grinding machine. SEM and optical microscope were applied to observe the surface morphologies of the diamond tools and granite. No obvious gathering of ultra-fine diamond grains were found in the new diamond abrasive tools, which exhibited a good wear-resistant ability in polishing. The granite surfaces polished by the new diamond tools were found to be basically smooth except few cracks originally existing in the granite.

Abstract: This paper reports experimental data on the wear of high-speed steel bimetal bandsaw blades cutting austenitic 17-7 stainless steel bars. Several different methods of assessing the wear modes and mechanisms are evaluated; Cutting and thrust force components, Set width, Kerf width, “Out-of-square” cutting, Wear modes and mechanisms and Chip characteristics. The wear mode established in the current work when bandsawing austenitic stainless steel with a bimetal blade is flank and corner wear together with formation of a cutting edge radius. The cutting edge radius increases as the wear progresses, reaching 25-50 mm after 300 cut sections. The established wear mechanism for the initial stages of wear is mild adhesive wear of the flank surface together with built-up edge formation and break-down. As the wear reaches steady-state the mechanism is adhesive wear of the flank surface with tempering/softening of high-speed steel layers. When the wear reached the steady-state region the level of thrust and cutting force were equal and relatively high. The kerf width appears to be less than the total set width of the blade, meaning that there is compression of the set teeth as they pass through the kerf. There is segmented chip formation with an increasing amount of vibration as the teeth wear, probably due to the increasing size of cutting edge radius. This work should be of great interest to the tool designer and user associated with bandsaws.