Papers by Keyword: Internal Grinding

Abstract: This study has been conducted to optimize the dressing parameters to find the minimum surface roughness for internal grinding of hardened SKD11 steel using the Taguchi method. The input parameters used are coarse dressing depth, number of coarse dressing, fine dressing depth, number of fine dressing, non-feeding dressing, and dressing feed speed. The Analysis of Variance (ANOVA) and an analysis of the signal-to-noise (S/N) response are conducted to estimate the significance of each input parameter on the responses. It shows that the number of coarse dressing has the most decisive impact on Ra (88.28%). Furthermore, the discrepancy of the roughness average from the experiments and that from prediction are minor.

Abstract: The article presents the results of the study of the quality parameters of the precise hole, depending on the size, spatial location and condition of the contacting surfaces, the parameters of the state of the contact zone, during finishing grinding. The correlation between the processing modes and the current parameters of the contact zone during internal grinding is established. Dependencies describe the flow cross-feed for the i-th turn increment of the depth of micro-cutting, compensation of radial material removal previous turn, deterioration of the wheel, the increment of the elastic and thermal strains. At the same time, the depth of micro-cutting and the increment of elastic and temperature deformations affect the values of the radial wear of the tool and the radial removal of the material. The equation of displacement balance is developed for discrete processes of hole processing with abrasive tools, during which the analyzed surface area comes into contact with the abrasive tool periodically.

Abstract: This paper aims to analysis the effect of coolant parameters on surface roughness in internal cylindrical grinding of annealed 9CrSi steel. The concentration and flow rate of the coolant are investigated in thirteen experiments by central composite design and response surface method. The effect of each parameter and their interaction on the surface roughness are analyzed by their regression model. From that model, optimal parameters are determined to obtain the minimum surface roughness. The measured roughness matches with the predicted roughness from the regression model. This proposed is proven and it can be further applied for optimizing other machining processes.

Abstract: Different grinding parameters of silicon nitride ceramic are researched at the process of internal grinding. The influences on the roughness of surface by the linear speed of grinding wheel (v_s), radial feeding speed (f) and axial vibration speed (f_a) are studied in the uniformity testing. The experimental equation of silicon nitride ceramic internal grinding is optimized. The machined surface morphologies of the ceramic specimen are measured by roughness instrument of Taylor-Hobson Surtroni-25 and scanning electron microscope of S-4800. The results show that with the increasing of the linear speed of grinding wheel the roughness of surface get reduced, and with the increasing of radial feeding speed the roughness of surface get raised. It is also inversely proportional to the axial vibration speed. The linear speed of grinding wheel has the biggest impact on the roughness of surface of the silicon nitride ceramic internal grinding among the three grinding parameters. With the increasing of linear speed of grinding wheel, the value of roughness of surface declines from 0.4095μm to 0.1726μm. The influences on the roughness of surface of the silicon nitride ceramic internal grinding by different factors are found out in the research, and its removal mechanisms are cleared up under different linear speeds of grinding wheel.

Abstract: Grinding is a main method of silicon nitride ceramic in finish machining stage. The technical parameters had an important influence on the surface quality of silicon nitride ceramic. The silicon nitride ceramic spindle was ground by the high-speed cylindrical grinder MGKS1432-H. The relations between different speed parameters and surface roughness were researched. The cylindrical and internal high speed grinding experiments of silicon nitride ceramics spindle were carried out. The S-4800 scanning electron microscope was used to explore the roughness change rule of the grinded surface under the condition of only changed grinding wheel’s velocity. In the process of cylindrical and internal grinding on silicon nitride ceramic spindle, the roughness tended to decrease with the linear velocity increasing, and increased with the radial feed speed increasing and decreased with the wheel shaft’s oscillation speed increasing. The result indicated that the linear velocity of grinding wheel influenced the sample’s roughness most. The effect of radial feed speed on the roughness is next only to the effect from linear velocity. The effect of shaft’s oscillation speed on the roughness is the lowest of the three factors. In the process of internal grinding, with the linear velocity increasing, the ceramic material transformed from brittle rupture to plastic deformation and the roughness appeared one peak. These results were very helpful to optimize the grinding parameters and improve grinding efficiency.

Abstract: In order to better reveal the theoretical nature of internal ultrasonic grinding which is an efficient grinding technology, the characteristics of grits motion is analyzed under axial vibration and the grits kinematic equation is established. By using Matlab the single particles trajectory is simulated, then the displacement of a grit is given at any time they contact. Through the theoretical analysis and Matlab simulation, we can achieve that for axial ultrasonic vibration the influences of axial feed on the grits trajectory is too litter to be ignored. So when calculate the contact length of the grinding wheel and the work piece, the grinding wheels axial feed can be neglected. Then the contact length of the grinding wheel and the work piece is achieved. It has a significant value for simplifying the calculation of the grinding force and the analysis of internal ultrasonic grinding.

Abstract: The present work deals with the simulation investigation of chip formation in ultrasonically assisted grinding (UAG) of SiC ceramics with single diamond abrasive grain in order to reveal the material removal mechanism in UAG of SiC materials. In simulation, smooth particle hydrodynamic (SPH）method coupling FEM modeling is employed to overcome the large material distortions that occur in the simulation analysis of single point cutting process when only the finite element method (FEM) is used. The abrasive-grain is modeled with finite element while the target workpiece is modeled by SPH particles. The simulation results revealed that normal and tangential forces in UAG are smaller compared to those in conventional grinding (CG) without ultrasonic vibration. The scratch profiles shows that the cutting path appears to be sinusoidal when ultrasonic vibration is introduced in grinding process, which leads to a higher material removal rate than that without ultrasonic vibration.

Abstract: A cutting-tool-type single-point diamond dresser, the tip of which has a given rake angle, was developed and its dressing and grinding performances were investigated. It was found that the dressing mechanism changes its mode from a ductile mode to a brittle mode with increasing back rake angle in the negative direction and that the cutting-tool-type dresser exhibits good robustness owing to the fact that its ground surface roughness is not markedly affected by the dressing conditions.

Abstract: Based on the in-depth study of embedded systems technology and characteristics of the ultrasonic vibration internal grinding process, the new CNC system for ultrasonic vibration internal grinding based on ARM and μC / OS-II embedded was proposed in this paper. For this system, the kernel of hardware is the 32 -bit embedded CPU LPC2210 with characteristics of high performance and low power consumption. And it is also equipped with the required peripheral modules to extend itself to one whole hardware system and the interface Circuit. Its software is based on μC / OS -II real -time embedded operating system, and the required application software needs to be developed so as to turn μC / OS- II real -time embedded operating system into one practical embedded ultrasonic CNC internal grinding.

Abstract: In this paper, the background of ultrasonic vibration internal grinding (UIG) technology was described; the main parameters of the UIG technology were summarized. The recent development of the UIG mechanism, system and ultrasonic vibration internal honing technology was overviewed. The development trend and future prospect of the UIG technology were proposed based on above analysis.