Efficient joint identification and fluted segment modelling of shrink-fit tool assemblies by updating extended tool models

Abstract

In milling, the dynamic behavior of the tool center point is crucial for estimating surface quality of the workpiece as well as the process stability behavior. Experimental-analytical receptance coupling can be used for predicting the tool tip dynamics but requires accurate analytical modelling of the holder-tool assembly. This includes the reliable identification of the holder-tool joint properties as well as the correct modelling of the fluted segment of end mills. However, the modelling effort associated with accurately representing the dynamic behavior of the fluted segment is significant. In addition, the joint identification requires a reference tool tip frequency response function of the tool assembly clamped in the machine spindle. This is inefficient and can also lead to incorrect estimation of joint properties. This paper provides an efficient method for joint identification and fluted section modelling using an offline, free–free excitation approach. The objective of this paper is to enable a direct comparison of the dynamic behavior of the freely constrained analytical tool assembly model with that of the real freely constrained tool assembly. The comparison of displacement to force frequency response at certain points on the tool assembly allows for the identification of tool model parameters such as the joint properties and effective diameter of the fluted segment. The comparability is realized by extending the analytical holder-tool beam model to include the receptance model of the standard spindle-holder interface. In this study, as an example, a thermal shrink-fit holder-tool beam model is extended to include an HSK-A63 interface. Subsequently, frequency response functions at two points on the real freely constrained tool assembly are measured in order to identify the joint stiffness and effective diameter of the fluted segment using the corresponding proposed formulations. The updated holder-tool model is then coupled with a 4-axis milling machine and validated. Despite the reduced modelling effort, a good prediction accuracy could be achieved for different holder-tool combinations.

Single artifact inverse RCSA with improved cross compliance identification

“…The algorithm exhibits good accuracy in cross-sectional property calculations and is efficient compared to classical FEM calculations. Likewise, Brecher [25] proposed an algorithm to simplify complex tools into beam models, streamlining the computational process.…”

Effect of elastic couplings on the dynamic behavior of transmission systems

“…Many studies have set up diverse methods for investigation of coupling complex systems. The receptance coupling (RC) method is used to couple subsystems with a joint component based on the Frequency Response Functions (FRFs) in the machine tools application [3,4]. This approach was suggested by Renand Beards [5] and Ewins [6] to characterize the interface properties.…”