Pet Preform Injection Molding Colour Change with EasyPurge Purging Compound
Opaque White to Clear
Goal: Scrap and cleaning cost reduction
Summary:
Machine: Husky Hypet 300
Extruder Diameter: 120 mm
Mould: 48 x 44.0grs
Material: PET
Colour: Opaque White 10% T. Oxide to Clear
Factory Location: Spain
Colour change current standings:
High scrap rates during colour changes when using purging compound in pellets.
Long downtimes due to the presence of colour streaks.
Normal results using virgin material:
Time: 1:10 Hour
Scrap: 450 Kgs
Purging Compound consumed: 25 Kgs
Using EasyPurge Purging Compound:
Time: 30 Minutes
Scrap: 200 Kgs
Purging Compound used: 1950ml
Pet Preform Injection Process
1. Seven shots were done injecting Virgin PET resin to remove the bulk of the colour contamination.
2. The dosing of Easypurge started automatically through the premixer using the automatic dosing device while the machine was still injecting preforms.
3. Both screw and hot runners were cleaned using Easypurge at 1.5%.
4. The Easypurge Automatic Purging System stopped adding purging compound.
5. The cleaning colour changes procedure was finished using virgin material to remove the rest of the purging compound leaving the hot runners clear of colour contamination.
Summary:
Purging compound used | Colour Time Change | Scrap | |
Pellet Purging compound | 25 Kgs | 1:10 Hr | 450 Kgs |
Easypurge: | 1,9 Kgs | 0:30 Hrs | 200 Kgs |
Comment by the Plant Manager:
“I said before the cleanup that nothing would be able to clean this stubborn opaque white. Easypurge got the job done reducing scrap by half”.