1. A dialogue system for the examination of a processing operation which is carried out on a machine tool to establish a proposal for improving at least one quality feature of a subsequent processing operation, the dialogue system comprising: input means through which an operator can identify the quality feature that is to be improved; and a proposal module that is configured to access stored expert knowledge, and to provide at least one proposal for improving the quality feature, wherein, to provide the at least one proposal, the proposal module is further configured to read one or more of data provided from a machine tool sensor system and image data of a processed workpiece together with associated material and processing data.