Review polyurethane durometer testing, Shore-scale selection, specimen conditioning and common measurement errors that affect reported hardness.
Jiacheng Dai 
Review graphite dosing in polyurethane production, including dry feeding versus slurry delivery, dispersion, abrasive wear and verification of material consistency.
Jiacheng Dai 
Understand the balance between polyurethane gelling and blowing, read reaction profiles, and trace defects through formulation and equipment variables.
Jiacheng Dai 
Explore gear-pump metering in polyurethane foaming machines, with sizing checks for viscosity, backpressure, recirculation and shot-weight consistency.
Jiacheng Dai 
Distinguish gel time from rise time in polyurethane foaming, review measurement methods, and interpret both values alongside material and equipment conditions.
Jiacheng Dai 
Understand functionality in polyurethane formulation and how changes in reactive-group count affect network structure, processing and material-data interpretation.
Jiacheng Dai 
Relate free-rise and molded density to polyurethane fill-weight calculations, and review the process variables that change density between a cup test and a molded part.
Jiacheng Dai 
Explore silicone surfactant effects on polyurethane foam cells, formulation compatibility and the interactions with metering, mixing and deaeration.
Jiacheng Dai 
Diagnose polyurethane flow marks by surface pattern, then review mold filling, material temperature, mixing and pressure controls as possible causes.
Jiacheng Dai 
Size polyurethane foaming-machine output from shot weight, cycle time and demolding needs, while accounting for metering accuracy and operating flow range.
Jiacheng Dai 
