Mold-Masters Fusion G2, User Manual

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12.2 Moisture Related Issues
Many common molding issues can be directly attributed to moisture
contamination of the production resin.
Generally, manufacturing resin is supplied from the manufacturer in ready to
process pellets that are in sealed, airtight containers. Follow manufacturers
storage instructions, keeping containers sealed until ready to use.
Prior to using pellets, follow the drying instructions, as provided by the resin
supplier and molding machine manufacturer if applicable.
12.2.1 Resin Moisture Contamination
Moisture can be introduced into the resin in many ways:
• during transportation
• environmental exposure (aging)
• malfunctioning heater / dryer
• extreme humidity in atmosphere
• inadequate or malfunctioning facility HVAC
12.2.2 Resin Drying Issues
During the drying stage of the resin (if applicable), ensure that:
• the resin pellets are not overpacked
• adequate air circulation is present
• the drying system is properly sealed, according to manufacturers
instructions
12.2.3 Importance of Pre-Drying Resin
Thermoplastic resins can be hygroscopic, able to absorb moisture from the
air. Under normal processing conditions, this can lead to degradation of the
polymer during molding. Breakage of polymer chains changes the properties,
resulting in possible blisters, streaks, splay or other defects described in this
section.
Recycled resins can have higher hygroscopic properties due to greater
surface area and should be dried separately from fresh resins.
If moisture issues are ruled out, continue with the troubleshooting tables in
the following pages.
12-2
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TROUBLESHOOTING
FSG2 User Manual