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A tentative work from the perspective of cutting forces is carried out in this paper to analyse and assess the robotic belt grinding mechanisms. Firstly, a microscopic scale of cutting force model consisting of sliding, ploughing and cutting components is introduced, then the effects of force components on the machined surface roughness are explored based on the force control experiments, and finally a typical case on the robotic belt grinding of aero-engine blade with constant contact force is conducted to validate the practicality and effectiveness of force control. The results reveal two significant findings with respect to the high sliding force percentage and low cutting efficiency in comparison with the robotic belt grinding without force control. [ABSTRACT FROM AUTHOR]

Calibration in the robot-assisted belt grinding of complex blades is regarded as one of the key bottlenecks of measurement accuracy. To enhance the accuracy, a TCP-based (tool center point) calibration method is proposed in this paper to calibrate the relationship between the precalibrated 3D laser scanner and the robot end-effector by using criterion spheres as the calibration object. Based on the description of the robot-scanning system from the perspectives of coordinates and scanner measurement modes, the calibration strategies on translational and rotational motions of the robot are provided to determine the translation vector and the orientation matrix. Calibration experiments on the criterion sphere are performed, both the calibration errors (positioning error and orientation error) and sphere fitting error are calculated. A typical case on the robotic belt grinding of 84K-2R1 aviation blade is conducted to validate the calibration results. Finally, the key factors influencing the calibration accuracy are analyzed. It has been demonstrated that the TCP-based calibration method proposed is effective, concise, and time-saving, and can be widely applied in the robot-assisted belt grinding operation. [ABSTRACT FROM AUTHOR]

This work is motivated by the overestimation of chip formation contribution due to the unspecified proportion of ploughing and chip formation in previous studies on mechanisms of belt grinding. In this paper, a microscopic scale of ploughing force model is introduced, and the characterisation of cutting mechanisms generated by robot-assisted belt grinding of titanium alloys is provided from the energetic aspect based on experimental forces. It has been demonstrated that sliding is more predominant than ploughing and chip formation in robot-assisted belt grinding process, resulting in lower energy efficiency. Strategies for balancing energy consumption and energy efficiency are suggested. [ABSTRACT FROM AUTHOR]

This work is motivated by the fact that one key parameter of r, which is defined as the effective contact radius of grain, in grinding temperature calculation model (TCM) proposed by Marinescu et al. is usually assumed as a constant in the range of 5-20 μm in different grinding conditions, and this assumption often leads to poor prediction accuracy and limits the widespread application of this model. In this paper, an improved temperature calculation model (I-TCM) considering the grain geometry and distribution is proposed to further optimize the grinding temperature. In this new model, the convection heat transfer coefficient ( h) is modified considering the cone angle ( θ), grain size ( g), and grain concentration ( V) effects, and the 'workpiece-wheel' partition ratio ( R) is improved considering the cone angle effect. Theoretical analysis and experiments are carried out for verification in details. The results show that the I-TCM gives the better match with the experimental results than the existing TCM, in which the R values characterized by the cone angle and effective contact radius of grain are more sensitive to the grinding temperature than the convection heat transfer coefficient. Furthermore, the effects by the grain size and grain concentration on the grinding temperature could be negligible for the simplification of the calculation process. The I-TCM given in this paper is helpful to the optimization and control of temperature in a practical grinding process. [ABSTRACT FROM AUTHOR]

In order to estimate temperature distribution and the influence of grinding parameters on grinding temperature in the grinding zone, a theoretical model used for calculating and simulating the grinding process must be established. Many simplified heat source models developed previously have some errors compared with the actual heat flux to the workpiece. Therefore, based on the triangular heat flux distribution model and temperature distributions measured, an inverse method for the heat transfer mechanism in the grinding zone was investigated and a quadratic curve heat flux distribution model was developed to determine the heat flux distribution and predict the surface temperature of the workpiece. From the theoretical expression of heat flux to the workpiece, it has been found that the quadratic curve heat flux is the superposition of square law heat flux, triangular heat flux, and uniform heat flux in the grinding zone. By comparison of theoretical analysis with the experimental results, it has been demonstrated that the solution using a quadratic curve heat flux can improve the grinding model by decreasing the error, although the uniform and triangular heat fluxes can explain the condition of the heat flux to the workpiece along the grinding zone. [ABSTRACT FROM AUTHOR]