The conventional criteria for mixer control actions are mixing time, batch temperature
and mixing energy [26]. Mixing time is entirely ‘open-loop’ in that there is no
compensatory action for variation of material input or mixer temperature. Both batch
temperature and mixing energy are influenced strongly by the progress of mixing and
provide some closed-loop control, shortening or extending the mixing time in response
to changes in material input and mixer temperature. Mixing to target temperatures gives
better control of the chemistry of mixing (cure behaviour) than target energy but the
latter is preferable when control of the physics of mixing (filler dispersion) is paramount.