Why do black specks occur?

Why do black specks occur?

Black specks are one of the most stressful defects for injection moulding or extrusion technicians, as they may or may not have a pattern of behaviour. We know, without a doubt, that these black dots indicate a certain level of degraded material within the system. It...
PA to HDPE

PA to HDPE

Extrusion Blow Molding Material Change with EasyPurge Purging Compound PA to HDPE Goal: Material change and Black Specks Removal Summary:  Machine: Moretti  Extruder Diameter: 100 mm Material: PA to HDPE Colour: Black to Clear Industry: Automotive Factory Location:...