Pet Preform Plastic Injection Molding Process: Color Change with EasyPurge Purging Compound
OPAQUE White to Clear
Goal: Color change time reduction
Summary:
Machine: Netstal 3500-3700
Extruder Diameter: 135 mm
Material: PET
Colour: Opaque White to Natural
Mould: 54 x 64 grs
Factory Location: USA
1. Original Prefrom Color: Opaque White.
2. First, once the barrel and the piston were cleaned with Easypurge purging compound, virgin PET started to be injected into the mold.
Easy purge was dosed into mixer using Easypurge’s Automatic Purging System (APS).
3. Easypurge emulsifies colour pigments injecting preforms in automatic.
4. The Easypurge Automatic Purging System stopped adding purging compound.
The process was finished using virgin PET to remove the rest of impurities and colour pigments emulsified by Easypurge.
5. Finally, the dosing of Easypurge was stopped, using virgin material to remove the rest of the purging compound leaving the hot runners clear of colour contamination.
Notes:
The machines parameters were adjusted due to an increase of the MFI.
24 hours later we confirmed there was no presence of White PET contamination during the next two shifts.
Color Change During Plastic Injection Molding Process: Final Results
Purging Compound used | Scrap | Colour Time Changes | |
Pellet Purging compound | 48 Kgs | 700 Kgs | 3:30 |
EasyPurge | 1050 Kgs | 300 Kgs | 1:30 |
Comment by the Process manager:
“Cleaning Hot Runners in automatic with Easypurge doser is helping us a lot, since we work with 18 different colours .”