Extension of the Stream-of-Variation Model for General-Purpose Workholding Devices: Vices and Three-Jaw Chucks

Abstract

Nowadays, advanced manufacturing models such as the Stream-of-Variation (SoV) model have been successfully applied to derive the complex relationships between fixturing, manufacturing and datum errors throughout a multi-stage machining process. However, the current development of the SoV model is still based on 3-2-1 fixturing schemes and, although some improvements have been done, e.g. N-2-1 fixtures, the effect of general workholding systems such as bench vices or 3-jaw chucks has not yet been included into the model. This paper presents the extension of the SoV model to include fixture and datum errors considering both bench vices and 3-jaw chucks as a fixturing devices in multi-stage machining processes. The model includes different workholding configurations and it is shown how to include the workholding accuracy to estimate part quality. The extended SoV model is validated in a 3-stage machining process by both machining experimentation and CAD simulations.