Advanced Materials Research Vol. 797

Abstract: Coordinate transformation in robotic abrasive belt polishing system and the calculation method of robot working point by cutter-contact point data are analyzed in this paper. Calculation process of cutter-contact point data is given in this paper, the process mainly includes acquisition and discrete of polishing tool path and the associated vector calculation. Subsequently, detail of the process such as tool path pattern, row spacing, step distance and best contact conditions are analyzed and calculated. Finally, in visual studio environment, the cutter-contact point data of gun-receiver surface is generated by calling UG / Open API function.

Abstract: This paper provides an analysis of the processing status and the existing problems of leading and trailing edges, and proposes a new seven-axis linkage CNC grinding method. Whats more, the paper carries out the forging blade edge abrasive belt grinding experiment. Finally, on the basis of experimental result, grinding process parameters are optimized, and the improved scheme is put forward. Through the experiment, the feasibility of the seven-axis CNC abrasive belt grinding method is verified.

Abstract: An experimental investigation is reported on the grinding of a titanium alloy using electroplated CBN wheels with water-based grinding fluid and wheel surface cleaning fluid applied at high pressures. This work was motivated by applying grinding fluid and wheel surface cleaning fluid both at high pressures for avoiding wheel loading, which is commonly seen in titanium alloy grinding. The objective is to explore the feasibility to grind titanium alloys with electroplated CBN wheels and high pressure wheel surface cleaning fluid for enhancing material removal rates. Straight surface grinding experiments were conducted on titanium alloy blocks in both shallow depth of cut and creep-feed modes. Grinding power, forces, and surface roughness were measured. Specific material removal rates of 8 mm²/s in shallow cut mode and 3 mm²/s at a depth of cut as high as 3 mm in creep-feed mode were achieved without burning and smearing of ground surfaces. It was showed that it is feasible to grind titanium alloys with electroplated CBN wheels at enhanced removal rates by applying grinding and wheel cleaning fluid at high pressures.

Abstract: This paper introduces the micro-abrasive suspension jet polishing technology in precision machining technology. In order to understand the micro-abrasive suspension jet erosion morphology and material removal mechanism, the erosion experiments of micro-abrasive suspension jet on 40CrMnMo7 special steel work-piece were taken. We found that when the incident angles are 90°, 60°, 30°, the polishing area is respectively annular shape, horseshoe shape and blade shape. During the erosion process, as the incident angle becomes smaller, most amounts of abrasive particles impact angles will also be small, and these cause more material removal. When the particles impact the work-piece with small angles, most particles play shearing action on the work-piece and leave the work-piece nanoscale scratches; while the particles impact the work-piece at large angles, extrusion and blow are formed by the majority of the particles on the work-piece, leaving different small size pits.

Abstract: t is challenging to achieve good surface quality and high efficiency simultaneously when machining thin film solar panels. In this study the machining characteristics of a multilayered thin film structure were investigated using diamond wire sawing and grinding. It was found that the efficiency in sawing was significantly greater than that of the employed grinding process, but the machined surface quality was much worse. The results indicated that grinding could still be the solution for such processing and sawing must be improved before this technology could be further progressed for machining thin film multilayered structures.

Abstract: Grinding experiments were carried out in wet, with MQL, in dry, with a spray of dry ice particles and various gases to examine influence of grinding atmospheres on the grinding performance in the combination surface grinding of steel and WC with a diamond wheel. From the experimental results, it was found that the grinding with inert gas injection which reduces an oxygen concentration at the grinding point would proceed a processing at more stable grinding force, resulting in less wear of the diamond abrasives.

Abstract: Alumina is a material that is frequently used in high performance applications. Grinding of alumina is usually associated with micro-cracks which deteriorate surface quality. In order to get a deeper knowledge of the characteristics of material removal mechanisms in alumina during grinding with and without ultrasonic vibration of the workpiece, single grit scratch tests were performed in this research. The effect of the ultrasonic vibrations and cutting speed on the material removal mechanism of alumina was investigated in the chip thickness range of 0.53 μm which is common in precision grinding operations. It was shown that the material pile-up decrease with higher cutting speed. On the other hand, the transition from ductile to brittle mode of material removal occurs earlier in higher cutting speeds. The ultrasonic vibrations showed great influence in the cutting speed 30 m/s in reducing the pile-up values.

Abstract: According to the demand of precision machining for optical aspheric lens, especially large scale optical aspheric lens, this paper presents an error compensation technique for precision grindging. Based on precision surface grinding machine (MGK7160), grating-type parallel grinding method is put forward to realize grinding paths planning for optical aspheric lens. In order to obtain surface metrology and evaluation after grinding, an on-machine measurement system is built. On the basis of compensation principle, machining error is separated to achieve error compensation. Grinding experiments are carried out and show that it can meet the demand of precision grinding, and the accuacy after error compensation attains 6.5μm.

Abstract: t can particularly generate abundant cavitation bubbles in the processing of the power ultrasonic honing. The dynamics of cavitation bubbles in the grinding area are very vital to study the machining mechanism and the cutting chatter of power ultrasonic honing. Based on the Rayleigh-Plesset equation, a new dynamics model of cavitation bubble is established, considering the velocity of ultrasonic honing and honing pressure. With the superposition principle of velocity potential, the dynamics of double cavitation bubble is also established. Moreover, the dynamic characteristics of cavitation bubble also can be simulated numerically. The results show that cavitation bubble in the grinding zone begins to grow extensively and then undergoes collapse, and even subsequent rebound and then. The variation trend of radius change of double cavitation bubble in the grinding area is more than that of single cavitation bubble by an order of magnitude.

Abstract: High speed grinding technology has great help about high speed grinding in application to the grinding of titanium alloy. In order to search the efficiency way to grinding the difficult to grinding material, the high speed grinding tests of titanium alloy Ti6Al4V were systematically conducted by using three wheels: brazed CBN wheel, ceramic bond CBN wheel and electroplated CBN wheel. Different equations of the maximum undeformed chip thickness a_gmax are adopted for different wheels based on their topography. The experiment results revealed that the grinding forces are increasing following the increasing of a_gmax, and the forces decrease slightly while the grinding speed v_s rise, the specific energy decrease with an increase in undeformed chip thickness firstly then reduce slightly. Particllarly, the removal rate is highest for brazed CBN wheel when the same specific energy is consumed. These phenomena indicate that with adopting the reasonable a_gmax, high speed grinding with brazed CBN grinding wheel can improve the grinding efficiency and reduce the energy.