A new measurement system to determine stiffness distribution in machine tool workspace

Abstract

This paper presents an innovative system determining machine tool quasi-static stiffness in machining space, so-called Stiffness Workspace System (SWS). The system allows for the assessment of the accuracy of a machine which has become a vital aspect over past years for machine tool manufacturers and users. Since machine tools static stiffness is one of the main criteria using to evaluate the machines' quality, it is crucial to highlight the relevance of experimental and analytical stiffness determination methods. Therefore, the proposed method is applied to estimate the spatial variation of static stiffness in the machine tool workspace. This paper describes the SWS system—its design, working principle, mounting conditions and signal processing. The major advantage of the system is the capability to apply forces of controlled magnitude and orientation as well as simultaneously measure the resulting displacements. The obtained results give possibility to estimate and evaluate static stiffness coefficients depending on the position and direction under loaded conditions. The results confirm the validity of the analyses of spatial stiffness distribution in the machine workspace.

Measurement and identification of generalised translational static stiffness in machining space of five-axis machine tool

“…All the modi cation mention in Section 2.2 contribute improvement to the results accuracy and reduce the total measurement time. Obtained results (Table 2) con rm the improvement in terms of uncertainty ranges in reference to outcomes reported in previous work [10]. In order to determine the static stiffness a new methodology was proposed which base on the model of rigid body motion and generalised coordinates (Section 2.1).…”

“…Due to the purpose of this article, it is crucial to point out changes made in the SWS system in comparison with the previous work [10]. All the modi cation mention in Section 2.2 contribute improvement to the results accuracy and reduce the total measurement time.…”

“…Then, it describes the technical solutions that have been implemented. This research work is a rst step towards expanding the prototype of the SWS; thus, some parts of this section are written in reference to [10].…”

“…The duration of each measurement cycle has been 80 seconds. This means that the measurement time was extended which is more appropriate for analyses in terms of quasi-static [10].…”

“…In a previous paper [10], the system determining machine tool static stiffness in workspace, so-called Stiffness Workspace System (SWS) was introduced; its design, working principle, mounting conditions and signal processing were described. In the present paper, further development of the SWS is discussed.…”