Optimization of Honing Surface Roughness of Carburized Holes Based on GRA-RSM

The carburized holes processed by ordinary internal grinding are prone to burn, crack, and low efficiency. Honing has a superior machining efficiency and cooling effect compared to traditional internal grinding. In this paper, we innovatively apply honing to carburizing hole grinding and propose an effective optimization scheme to enhance the surface finish of carburized holes. We set up an experimental system to explore the influence law of honing head rotation speed, axial reciprocating speed, grain size, and single grinding depth on surface roughness. Based on the grey correlation and response surface method, we propose a method to optimize the honing parameters of carburized holes and establish a prediction model, which has an R2 value of 0.9887, indicating that the model fits well. We verify the validity of the model by the root mean square error of 0.012 between the measured and calculated values. Based on the model, the optimal parameters of roughness (Ra) is obtained and verified by experiments. Compared with the original honing parameters, the surface roughness quality is improved by 25.8%. It shows that the optimized honing process based on the GRA-RSM method improves the surface quality of carburized holes significantly.

Determining the Optimum Set of Dressing Parameters Satisfying Minimum Surface Roughness when Conducting the Internal Grinding of Hardened SKD11 Steel

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.

The Correlation of Movements in the Technological System during Grinding Precise Holes

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.

Simulation of the stock removal in the contact zone during internal grinding of brittle non-metallic materials

Introduction. Finishing operations, in particular, cylindrical grinding, essentially form the quality parameters of products, its performance characteristics and functional suitability. At the same time, the cost of grinding work increases significantly in comparison with grinding metals, reaching an average of 20 ... 28% of the total cost of manufacturing products. The selection of the optimal parameters of the technological system based on the process simulation can improve the reliability, productivity and economic efficiency. To describe the processing of brittle nonmetallic materials, empirical dependences are mainly used, and the existing analytical models do not take into account the stochastic nature of the grinding operation and the combination of microcutting and brittle chipping when removing particles of brittle nonmetallic material and wear of the surface of the grinding tool. Purpose of the work: simulation of stock removal in the contact zone during internal grinding of brittle non-metallic materials. The task is to study the features and patterns of change in the probability of material removal when the treated surface comes into contact with an abrasive tool. In the work, the theoretical and probabilistic models are obtained, allowing to reveal the patterns of material removal in the contact zone. The models make it possible to trace the regularities of the interaction of cutting and piercing grains on the surface of the workpiece and the process of removing the allowance in the contact zone due to a combination of the phenomena of microcutting and brittle chipping, considered as a random event. The research methods are mathematical and physical simulation using the basic provisions of the theory of probability, the laws of distribution of random variables, as well as the theory of cutting and the theory of a deformable solid. Results and discussion. Data are obtained that provide a clear illustration of the patterns of material removal along the contact zone at various levels. Analysis of the results obtained shows that the peripheral speed of the tool and the rotation speed of the workpiece, which are directly included in the equation for calculating the probability of material removal, significantly affect the rate of material removal. The cross feed also has a significant effect on stock removal. A qualitative picture of the change in the probability of material removal in the contact zone during grinding of holes in brittle nonmetallic materials is obtained. The obtained patterns of change in the probability of material removal when the machined surface is in contact with an abrasive tool and analytical dependences are valid for a wide range of grinding modes, tool characteristics and other technological factors.

A High-Speed Precision Bearing Internal Grinding Machine and Grinding Process

In order to meet the requirement of grade P2 bearing grinding, we designed a high-speed internal grinding machine used for bearing raceway and inner circle grinding. The machine adopts T-type layout and 4-axis NC linkage. It is supported by hydrostatic pressure and driven directly by torque motor. Besides, it is equipped with high-speed hydrostatic grinding wheel spindle of ELKA. Our design includes hydrostatic workpiece shaft, hydrostatic turntable and hydrostatic guide rail. The design of this machine can ensure the high-speed grinding process and research has good engineering application value. Finally, the designed precision grinding machine is used to grind the P2 bearing raceway with reasonable processing technology.