Papers by Author: Yu Can Fu

Abstract: Heat transfer performance of the heat-pipe grinding wheel (HPGW) is mainly depended on the heat pipe in the wheel. In this paper, a basal body of HPGW was developed and a heat transfer experiment was performed to study the effect of the parameters of the heat pipe such as liquid filling ratio and rotating speed on the heat transfer performance of the HPGW. Results show that the heat transfer performance decreases if the liquid filling rate is too large or too small under the same heat source intensity and the optimal liquid filling rate is about 35% of the volume inside the heat pipe. The heat transfer performance of the HPGW is enhanced with the increasing of the rotating speed. The analysis of the results also shows that the heat pipe in the HPGW can play a great role on enhancing the heat transfer in the grinding zone with suitable processing parameters.

Abstract: Localized ultra-high frequency induction brazing is proposed to deal with the thermal deformation problem of brazed diamond tools. In order to investigate the temperature field distribution, the simulation model of induction brazing for solving the temperature field is described through the FLUX 2D software. The experiment is carried out to verify the numerical simulation result. Good agreement is observed between experimental value and simulation result. The influence factors on temperature field are investigated by the simulation software. Ultra-high frequency induction brazing with diamond grits is carried out based on the conditions given by simulation results. Good bonding between the diamond grits and the filler alloy is observed and the width of the brazed region is less than 3 mm.

Abstract: During dry grinding of titanium alloy, workpiece burn and chips adhesion phenomenon always takes place, which influences the surface quality of the machined components. In this paper, the solid lubricants, composed of graphite and polyvinyl butyral, are covered on the brazed cubic boron nitride (cBN) mounted wheels using the ultrasonic vibration method. Test of grinding of titanium alloy Ti6Al4V is carried out with the above tools. Comparative dry grinding tests are carried out to reveal the performance this new-type abrasive tools. Experimental study shows that the grinding temperature with the cBN grinding mounted wheels covered by graphite is lower than that of non-lubricant-covered wheels; the grinding surface with the cBN mounted wheels covered by graphite is remarkably improved with a roughness Ra lower than 1.5 μm. And graphite lubricant participates in grinding operation constantly.

Abstract: Titanium Matrix Composites (TMCs) parts usually requires high mechanical performance. The good workpiece surface quality and long tool life is the two target of finishing machining. In this paper, finishing turning tests are performed to investigate the workpiece surface roughness and tool life of machining TMCs with Polycrystalline Diamond (PCD) tools at the cutting speed range 60m/min to 120m/min. The results show that the workpiece surface roughness is obtained range Ra 0.44 to Ra 0.53m. tool life reaches about 10.6min, 7.9min, 7min and 5.5min at the cutting speed of 60m/min, 80m/min, 100m/min and 120m/min, respectively.

Abstract: High-speed milling tests were performed on SiC_p/2009Al composites in the speed range of 600-1200m/min using PCD tools to investigate the cutting temperatures and the influence factors. The results showed that the cutting temperature could reach 580°C under the given cutting conditions. Graphitization took place on the PCD tools under the high cutting temperature coupled with the effects of abrasive wear of SiC particles and catalysis of copper in the 2009 aluminum matrix. Cutting parameters, tool materials, workpiece materials and tool wear condition had significant effect on the high speed milling temperature while tool geometries had the minor effect. Among these influence factors, cutting speed was the most significant factor. Reinforcement volume fraction was the less significant factor and followed by radial depth of cut, feed rate and tool materials.

Abstract: This paper deals with an investigation of surface integrity of Ti6Al4V alloy with zirconia alumina and SiC belts. The experiments were conducted under dry grinding environments in milling machine XS5040 equipped with belt grinding device. Microcosmic geometry parameters were measured with TALYSURF5 instrument, the surface morphology machined workpiece and the phase structure was analyzed using 3D viewer microscope, surface hardness for ground surface was measured by HXS-1000A instrument. The results show that surface quality maintain better level during a long period, the grinding affected zone was small(≤15μm), zirconia alumina belt has excellent performance than SiC belt during dry grinding Ti6Al4V alloy.

Abstract: This paper was dedicated to elucidate an investigation of abrasive wear and surface topography of Titanium alloy TA15 on dry grinding with zirconia alumina belt. In the investigation, experiments were performed on milling machine XS5040 equipped with assembled belt grinding device. The wear abrasive, surface morphology of machined belt in different phase were analyzed using 3D viewer microscope. The results show that the wear of belt abrasive is mainly steady attritions wear since zirconia alumina belt was stable on dry grinding. At higher grinding force, the abrasive was found to undergo dislodging prior to being gradually worn. So zirconia alumina belt has excellent performance in the dry grinding titanium alloy.

Abstract: The dressing methods of monolayer diamond tool have recently been developed increasingly because a substantial improvement of the ground surface roughness could be achieved with the dressed monolayer diamond tools. In this paper, a new dressing method was proposed, namely chemical-mechanical dressing of the diamond grits. Dressing experiments were carried out on the monolayer brazed diamond grinding wheel. The grit-tip distances from the base of wheel substrate were measured before and after dressing. Grinding experiments were conducted on K9 optical glass after each dressing interval. The roughness parameters of the ground surfaces were measured. The outcome of this attempt appeared highly encouraging, and the dressing of monolayer brazed diamond grinding wheel is effective with the chemical-mechanical dressing.

Abstract: High speed milling tests were performed on the SiCp/2009Al composites to investigate the cutting forces by using PCD tools in the speed range of 600-1200m/min. The results showed that the peak value of the cutting force Fy (in the tool radial direction) was in the range of 700-1450N under the present cutting condition. The maximum amplitude of cutting force vibration in the tool radial direction can reach 700N. Cutting forces increased with increasing feed rate or radial depth of cut and decreased with increasing cutting speed. Negative rake angle and relatively large tool nose radius were recommended as far as cutting forces was concerned. Materials with higher volume fraction or smaller reinforcement particle size had the bigger cutting forces. T6 heat treatment can increase the cutting forces significantly but the using of coolant can decrease the cutting forces evidently.

Abstract: Cu-Sn-Ti brazing alloys are gaining importance as active brazing alloys for brazing diamond tools. The microstructure at the interface between diamond or Ti-coated diamond grits and Cu-Sn-Ti brazing alloy and bonding strength have been investigated in this paper. The results show that TiC layer forms between diamond and alloy matrix during the brazing process and Sn- and Ti-based intermetallic phase forms between TiC and the bonding matrix. And compound SnTi₃ forms between the Ti-coated diamond grits and Cu-Sn-Ti brazing alloy. Furthermore, the bonding strength between Ti-coated diamond grits and brazing alloy is higher than that between diamond grits and brazing alloy.