The machine is being cleaned in preparation for a porcelain run. The machine has been stripped down completely and all the casings and augers and other parts have been washed and dried separately. These must be installed (in the main chamber, the vacuum chamber and in the nose). Clean-downs like this are an indicator of the quality delivered by the production crew.
The practice of removing air from clay as it is pugged. Deaired clay has better forming properties and produces a smoother fired surface.