Measuring and modelling of process forces during tapping using single tooth analogy process
- PDF / 2,080,505 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 75 Downloads / 182 Views
PRODUCTION PROCESS
Measuring and modelling of process forces during tapping using single tooth analogy process F. Geßner1 · M. Weigold1 · E. Abele1 Received: 7 September 2020 / Accepted: 16 November 2020 © The Author(s) 2020
Abstract For machining internal threads, tapping is a commonly used process. However, due to the complex geometry of the tapping tool, each tooth has a unique geometry resulting in individual forces. Since the forces act synchronously during the process, they partly compensate each other. However, since resulting forces in tapping can cause undesired deflection of the tool which can lead to threads that are not true to gauge or tool breakage, the knowledge of the forces is crucial. To predict the occurring forces on each tooth, different modelling approaches can be used. An approach based on the chip load-cutting force relationship is the mechanistic modelling. Therefore, a suitable force model is of central importance. An empirical force model can be established using an analogy process. Within this work a single tooth analogy process is presented to measure the forces of each tooth separately. By means of a geometrical analysis of the real tool, the chip sizes, such as the cross-section area of the undeformed chip are calculated. Merging the measured process forces from the analogy process and the actual chip sizes, an empirical force model is set up using multivariate regression. The model is validated by implementing it in an existing framework and comparing the results to experimental data. Keywords Tapping · Modelling · Force · Torque · Analogy process
1 Introduction Threaded joints are widely used as detachable connecting elements. In addition to thread milling and thread forming, tapping is a common process for the machining of internal threads. In tapping, material is removed from the bore wall in a continuous cutting process, whereby the thread is cut successively by the tooth of the tap. Since the process is located at the end of the value-added chain, tool failure is associated with expensive rework or component scrap [1]. The industry is therefore constantly striving to increase process stability to reduce failures and the need for human intervention [2]. To achieve this, it is necessary to increase the understanding of the tapping process. This includes especially the forces acting during the process. Due to the * M. Weigold [email protected]‑darmstadt.de F. Geßner [email protected]‑darmstadt.de 1
Institute of Production Management, Technology and Machine Tools (PTW), Otto‑Berndt‑Str. 2, 64287 Darmstadt, Germany
individual geometry of each tooth the load distribution on the tap is not even, resulting in radial forces (see Fig. 1) that can lead to a lateral deflection of the tool. However, these forces act synchronously and are partly compensated by the complex contact conditions between tool and component, which means that they cannot be measured directly in the real tapping process. Therefore, an analogy process is necessary to measure the process forces on each tooth se
Data Loading...
