Extruded tube generates static charges while cooling. A water bath will act as an earth neutralising charges on the outside only, while drying and machining will regenerate greater charges.
Swarf and environmental contamination will be attracted to the surface of the product.
Contaminated material will cause problems when printing, laminating & finishing. Storage damage due to swarf abrasion is also a manufacturing problem.
Neutralising charges on the tubes will remove the risk of electrostatic attraction to the product from the local area. The example shows a Meech 957 air curtain which promotes additional cooling and static neutralisation.