Simulation Based Prediction of Compliance Induced Shape Deviations in Internal Traverse Grinding

Abstract

Internal traverse grinding (ITG) using electroplated cBN tools in high-speed grinding conditions is a highly efficient manufacturing process for bore machining in a single axial stroke. However, process control is difficult. Due to the axial direction of feed, changes in process normal force and thus radial deflection of the tool and workpiece spindle system, lead to deviations in the workpiece contour along the length of the bore, especially at tool exit. Simulations including this effect could provide a tool to design processes which enhance shape accuracy of components. A geometrical physically-based simulation is herein developed to model the influence of system compliance on the resulting workpiece contour. Realistic tool topographies, obtained from measurements, are combined with an FE-calibrated surrogate model for process forces and with an empirical compliance model. In quasistatic experimental investigations, the spindle deflection is determined in relation to the acting normal forces by using piezoelectric force measuring elements and eddy current sensors. In grinding tests with in-process force measurement technology and followed by measurement of the resulting workpiece contours, the simulation system is validated. The process forces and the resulting characteristic shape deviations are predicted in good qualitative accordance with the experimental results.

Improvement of Shape Error for Slender Parts in Cylindrical Traverse Grinding by Part-Deformation Modelling and Compensation

“…K is dependent on whether the section is in front (10) or behind (11) the load application point. First, every isostatic case, produced by every support and force, was solved, considering q, R F (reaction of the steady rest in the second diameter), R G (reaction of the steady rest in the third diameter), and R H (reaction of the steady rest in the fourth diameter).…”

“…Some research has been conducted to clarify and predict the deformation behavior of slender parts during the traverse grinding process, based on the radial force induced by the wheel pushing the workpiece, both in external [7,10] and internal [11] grinding processes. Having presented the prediction model, various solutions have been described to minimize the predicted shape error.…”

Application of the Coupled Eulerian Lagrangian method to the prediction of single‐grain cutting forces in grinding

“…In general, such kinematic models aim to approximate the interaction of each individual grain on the grinding wheel with the workpiece material but rely on simplified models for the interactions under consideration due to the large amount of grain engagements. We recently proposed a multi-scale simulation framework capable of simulating internal traverse grinding under consideration of elastic deflection between grinding wheel and workpiece, for which a model for the single-grain process forces was developed based on two-dimensional finite element cutting simulations [1]. The process forces could be predicted in good agreement with experimental observations, where the only experimental calibration was performed for the elastic compliance of the machining system.…”

“…A Lagrangian Finite Element scheme, based on the model presented in [5], was applied for the single-grain cutting simulations in [1]. Due to the large deformations during chip formation, a remeshing scheme is necessary for the simulations, which adds computational cost and introduces artificial diffusion of the solution variables.…”

“…Grinding tools, on the other hand, contain a large number of grains with varying geometric characteristics. We recently proposed a multi-scale simulation system for the simulation of ITG processes, where a geometric kinematic grinding simulation, based on a database of digitalised grains of a real grinding wheel, was used to determine the grain engagements [1]. The process forces were obtained from summation of the contributions of all active grains at any given time, based on a force model on the individual grain level.…”