Super-high Speed Grinding Research Articles

A comparison between conventional speed grinding and super-high speed grinding of (TiCp + TiBw) / Ti–6Al–4V composites using vitrified CBN wheel

Comparative grinding experiments of (TiCp + TiBw) / Ti–6Al–4V composites were conducted using vitrified CBN wheel at the conventional wheel speed of 20 m/s and the super-high wheel speed of 120 m/s, respectively. The grinding behavior, i.e., grinding force and force ratio, grinding temperature, specific grinding energy, and ground surface morphology were analyzed. The results obtained indicate that the normal and tangential grinding forces at the super-high wheel speed are smaller than that at the conventional wheel speed. However, the force ratio, the specific grinding energy, and the grinding temperature show a contradictory trend compared to the grinding force between the conventional speed grinding and the super-high speed grinding. The main defects of the ground surface of (TiCp + TiBw) / Ti–6Al–4V composites are voids, micro-cracks, fracture or crushed, pulled-out, and smearing.

Development and Key Technologies of High-Speed Grinding

The mechanism and characteristic of high speed grinding and the technology and development of high speed grinding were introduced. High efficiency grinding including ultrahigh speed grinding, high efficiency deep grinding, creep deep grinding and abrasive belt grinding was analyzed. The technology about manufacturing the spindle system in super high speed grinding and the other main interrelated technology about grinding were also described.

Review of Quick-Point Grinding Technology

Quick-point grinding technology, suitable to be applied in automobile manufacturing, cemented carbide and ceramic material processing industry, was an advanced ultra-high-speed grinding technology. It is the integration of super-high speed grinding, CBN super-abrasive and CNC flexible manufacturing and so on. The characteristics of quick-point grinding were systematically illustrated. Applications of this technology to process hard-machining materials and shaft parts were also given in this paper. Some problems and solutions corresponding to quick-point grinding technology were presented finally.

High Speed Grinding of Nickel-Based Superalloy with Single Diamond Grit

Nickel-based superalloy plays an extremely important role in gas turbine engines in aerospace industry. To understand the high and super high speed grinding mechanism of nickel-based superalloy, the single-grit grinding mechanism is needed to be investigated. Previous studies on single grit were all carried out by mean of cutting or scratching. In this work, a novel experimental set-up of single-grit grinding had been developed to meet the reality of the complex kinematic grinding process. Grooves and collected chips were investigated in grinding of a typical nickel-based alloy GH4169 with wheel speed up to 150 m/s. The groove integrity is improved by increasing the grinding speed even though the chip thickness is kept constant. The typical serrated chips were observed and the frequency of chip segmentation increases linearly with the increasing of the grinding speed. Under high and super high grinding, the thermal softening due to the high temperature in adiabatic shear zone contributes to accelerate the chip formation and leads to decrease the grinding force.

Application and Development of High-Efficiency Abrasive Finishing

High-efficiency abrasive machining is one of the important technology of advanced manufacture. Combined with raw and finishing machining, it can attain high removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high efficiency abrasive machining technologies relate to high speed and super-high speed grinding, high efficiency deep-cut grinding, hard and brittle materials high-efficiency grinding, powerful grinding and belt grinding were summarized. The efficiency and parameters range of these abrasive machining processes were compared. The key technologies of high efficiency abrasive machining, including grinding wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and workpiece and safety defended, as well as intelligent monitor and NC grinding were investigated.

Optimization of Segmented Grinding Wheel Matrix Based on Super High-Speed Grinding

It is different from the traditional integrated super high-speed grinding wheel, the centrifugal force has greater impact on segmented grinding wheel in super high-speed rotation. In this paper, in order to ensure the safety of super high-speed grinding wheel, models for the connection between inner micro-unit’s displacement and stress of wheel matrix were established to optimize high-speed grinding wheel section form, reduce the centrifugal stress and control the radial displacement of grinding wheel. Consider the structural and mechanical characteristics of wheel matrix, strength check of the theoretical formula were also established. Taking into account the factors of aerodynamic and wheel connector effects, at last the design of segmented super high-speed grinding matrix was optimized with finite element method.

Simulation and Experiment on the Residual Stress in Super-High Speed Grinding

In this paper, effective finite element model have been developed to simulation the plastic deformation cutting in the process for a single particle via the software of ABAQUS, observing the residual stress distribution in the machined surface, the experiment of grinding cylindrical workpiece has been brought in the test of super-high speed grinding, researching the residual stress under the machined surface by the method of X-ray diffraction, which can explore the different stresses from different super-high speed in actual, and help to analyze the means of reducing the residual stresses in theory.

Study on Thermal Properties of Hybrid Journal Bearing for Super High Speed Grinding Machine

As the high speed bearings, hybrid journal bearings are usually used in high and super high speed grinding machine spindle system. Since the bearing operates under high speed conditions, the excessive temperature rise of bearing is a key factor to lower the accuracy of the spindle system and limit the bearings working speed, so restrict the bearing applications. In this paper, the model of hybrid journal bearing is established to analyze the heat mechanism. In addition, the temperature field distribution for the certain hybrid journal bearing at high speed is studied by ANSYS considering the heat transfer characters between fluid and solid. The experiment of temperature for hybrid journal bearing system in super high speed grinding machine is also performed. The thermal properties and the measure for controlling temperature rise of such bearings are analyzed.

Study on the Correlative Mechanism of Super High-speed Point Grinding

By combining super high-speed grinding and point grinding technologies,a comprehension of super high-speed point grinding and its correlative technologies is given. Models of grinding wheel wear and loading are built. It is found that the point grinding wheel has more even loading,longer life and better grinding performance in comparison to the traditional cylindrical grinding. In the chip formation test of single abrasive grain under the condition of point grinding parameters,it is found that the actual cutting depth of abrasive grain is less than the theoretical one,and the reasonable explanation is given by the chip formation mechanism of single abrasive grain. From the analysis of successive chip formation mechanism of wheel and the motion trajectory of wheel relative to the workpiece,it is found that the workpiece axial feed speed should be lower than the critical value of the least rotary-cutting cycles for ensuring fine grinding surface. Point grinding is a superior rotary-cutting process which can realize large cutting depth,high material removal rate and good surface quality. As wheel spindle swivels,the grinding zone between wheel and workpiece is not closed,it is found in wet grinding experiment that there is larger grinding fluid passing though the grinding contact zone.

Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel

High-efficiency abrasive process with CBN grinding wheel is one of the important techniques of advanced manufacture. Combined with raw and finishing machining, it can attain high material removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high-efficiency abrasive machining technologies with CBN grinding wheel relate to high speed and super-high speed grinding, quick point-grinding, high efficiency deep-cut grinding, creep feed deep grinding, heavy-duty snagging and abrasive belt grinding were summarized. The efficiency and parameters range of these abrasive machining processes were compared. The key technologies of high efficiency abrasive machining, including grinding wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and workpiece and safety defended, as well as intelligent monitor and NC grinding were investigated. It is concluded that high efficiency abrasive machining is a promising technology in the future.

Investigation of Dynamic Performance of Super-High Speed CBN Grinding Wheel

The dynamic performance of the grinding wheel system is one of the key factors to affect the super-high speed grinding process The excessive centrifugal stress acted on the wheel body can make the wheel rupture due to the super-high rotary speed of the wheel. And the alternating centrifugal force caused by the wheel imbalance can not only make the spindle and bearings vibration and failure, but also lower the machining precision and the wheel life, as well as make against the safety. In this paper, the centrifugal stress of the high speed grinding wheel and its effect on machining process were analyzed by means of finite element analysis and simulation. The alternating centrifugal force and its effect on the wheel spindle system were investigated. Furthermore, the balance precision of super high speed grinding wheel and system was discussed for achieving the high precision, safety and efficiency machining process.

Experimental Study on Point Grinding Technical Parameters Affecting Coolant Jet Parameters

Point grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding force. Because of the lower grinding power, the grinding heat in point grinding process is much less than that of the conventional grinding process. Therefore, the less grinding coolant jet parameters can be used during point grinding process. That is very propitious to the environment and resource, as well as the green manufacturing. Based on the mathematic model of the edge contact area of point grinding, the simulations of the edge contact area with point grinding angles and depth of cut was performed to study the grinding power. In addition, the relations between the grinding power and the depth of cut and vertical grinding angle were investigated. The dynamic pressure and velocity distributions in the airflow layer around the wheel edge were analyzed more by means of experiment. The point grinding experiment for grinding coolant jet parameters was performed.

Simulation of Temperature Field of Oil Film in Super-High Speed Hybrid Journal Bearing Based on FLUENT

The hybrid journal bearing with the high rigidity and rotation accuracy has been used in super-high speed grinding machine in some cases. But the main shortcoming of hybrid journal bearing is the higher temperature rise in the oil film when bearing works, which can lower the bearing capacity and cause the bearing failure due to the drop of oil viscosity and the larger thermal deformation. Fluent is a special CFD soft to simulate and analyze the flow and the heat exchange of liquid in the complex geometrical field. In this paper, the simulations of the temperature field of the oil film in the super-high speed hybrid journal bearing were performed by Fluent based on the mathematical models. The simulation results can not only forecast the flow state and the thermal properties of the bearing oil, but also find the design limitation of the bearing for the more improvement of the bearing design.

Simulation of Dynamic Performance for Hydro-Hybrid Spindle-Bearing System of Superhigh Speed Grinder

Spindle-bearing system plays a crucial role in superhigh speed grinding, which directly affects machining precision, but it is complex and difficult to get the dynamic performance in experiment. This leads to study how to accurately simulate dynamic performance of spindle-bearing system. So a method which springs and damping units imitate bearing support is proposed in this paper. The proposed method can predict the regular pattern which bearing stiffness and damping ratio affect natural frequency and harmonic response. The research demonstrates that the method predicts well the dynamic performance of the spindle-bearing system and it is close to actual condition, therefore, it can be a reference for dynamic optimization design of spindle-bearing system in superhigh speed grinding.

A Study on Airflow Field of Super-High Speed Pectination Grinding Wheel Based on PIV

Adopting the method of PIV, systematical theory analysis and experiment research were made on the airflow field distribution of super-high speed pectination grinding wheel, as well as experiment design and data acquisition, the data processing was carried out through the software of FlowMap, Tecplot, and Matlab. By analysis and discussion focused on experiment results, the general rules of airflow field distribution in super-high speed pectination grinding wheel were preliminary drawn, which provides the research foundation with a view to find a new method for the effective supply of super-high speed grinding coolant.

Study on Effect of Grinding Fluid Supply Parameters on Surface Integrity in Quick-Point Grinding for Green Manufacturing

In high and super-high speed grinding process, there is an airflow layer with high speed around the circle edge of the grinding wheel that hinders the grinding fluid into contact layer, namely, the air barrier effect. The speed of airflow layer is directly proportional to the square of the wheel speed. Quick-point grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding power. The edge effect of the air barrier is weakened because the thin CBN wheel is applied in the process. By the analysis of dynamic pressure and velocity distributions in the airflow layer around the wheel edge, the mathematic models of the flow and jet pressure of grinding fluid for effective supply in the process were established and the process of optimization calculation of the jet nozzle diameter for green manufacturing was also analyzed based on the thermodynamics and the technical character of quick-point grinding process. The quick-point grinding experiment for surface integrity influenced by grinding fluid supply parameters was performed.

The Experiment Method of the Study on the Airflow Field around the Grinding Wheel in Super-High Speed Based on PIV

The investigation of the experiment method on airflow field around super-high grinding wheel by PIV (Particle Image of Velocity, PIV) instrument was introduced in the paper. The measure system and scheme were designed for the experiment with PIV applied in the super-high speed grinding wheel for the airflow. The processing method of experimental data was discussed and the experiment result validated the feasibility of the experiment method.

Theoretical Analysis and Simulation of Airflow of Super High-Speed Grinding Wheel

The airflow field of super-high speed grinding was analyzed in the paper and the method of computing and analyzing the distribution of the field has been brought forward by applying boundary layer theory. Adopting the method of finite element, the model of airflow field in the 3-D grinding zone has been built up by using software; the solving strategy and the boundary conditions has been defined, where artificial viscosity coefficient in the repetitive and continuous analysis and the method by applying inertia relaxation have been discussed, which helped to revolve stability. The results of simulation was given and analyzed, which can be validated with experiment by using the equipment of PIV (particle image of velocity).

Researches and Simulations on Hydrodynamic in Super High Speed Grinding Area

It analyzed the conditions in hydrodynamic action of coolant in super high speed grinding area and described the conception of lubricate induce force in the paper. Using fluid dynamical lubrication theory, theory analyses and mathematics modeling on lubricate induce force in plane grinding with non-porous grinding wheel were carried out, also the computer simulations were done, and the conclusion was theoretically verified by tests in interrelated material documents. On the bases of this, by analyzing the effects of parameters and pointing out grinding wheel speed, grinding wheel width significantly influences the max dynamic pressure in grinding area, thus the analyses indicated that it rises with the speed of grinding wheel increasing.

Model Establishment of Chip-Formation due to Shock under Ultra-High Speed Grinding

The theory model of the indent experiment of the brittle material was established, its specific energy was analyzed, and the calculation expression of the total specific energy for a single grain was given. Experiment process and results were given. Ultra-high speed grinding experiment was done, and its results were obtained. After the results were analyzed, the conclusions were gained that brittle materials could produce ductile-regime grinding under ultra-high speed shock. The model of mechanism of chip-formation due to shock in quasi-fluid phase on super-high speed grinding was established, and the chip formation hypothesis for the chip formation mechanism on ultra high speed grinding was produced.