Closed Loop Piezoelectric Core Compensation for Polymer Thermal Shrinkage
Dynamic piezoelectric core compensation applies localized physical packing during cooling to eliminate shrink voids and hold DIN 16742 TG3 tolerances.
Melt Phase Change
Meaning
The transition of a thermoplastic resin from a highly structured crystalline or amorphous solid to a flowing liquid happens in the extruder barrel. Driven by shear heating and heater bands, melt phase change allows the polymer chain network to flow through the nozzle and gate. Controlling this transition prevents un-melted pellets from blocking the nozzle or entering the mold cavity, which would cause physical cosmetic defects in the finished part.
Polymer Flow
Energy consumption during polymer processing depends largely on the latent heat of fusion required to melt the polymer. Achieving a complete melt phase change is necessary to ensure a homogeneous melt flow and prevent variations in part density.
Thermal Cycle
Barrel temperature settings must be managed to ensure that the resin melt transition occurs at the correct position along the screw. If the melting starts too early, the polymer can stick to the screw feed zone, which leads to erratic feeding and screw slippage. When melting is delayed, the resin leaves the barrel with solid core remains, causing severe weakness in the molded part.
Quality Outcome
Sourcing high-quality raw materials helps to minimize variations in the melt phase change of the polymer. Regrind resins often have different thermal histories, which can alter the melting point and viscosity of the blend. Measuring the transition of each incoming batch with differential scanning calorimetry prevents molding defects, because the process parameters can be adjusted beforehand.
This screening prevents the formation of cold slugs in the nozzle, protecting the aesthetic finish of the molded part.