If you're searching "CPU casting defects", "bubbles in cast polyurethane", "vacuum degassing polyurethane elastomer", "pot life control", or "cast urethane curing temperature", you're already close to the key point: great CPU parts come from both good chemistry and correct processing.
CPU manufacturing basics (and why process matters)
Cast polyurethane elastomers are formed when prepolymers react with chain extenders, then the system cures into a 3D network structure. During production, the mixed liquid remains workable for a limited time (pot life) and then solidifies. In many systems, elevated temperature curing helps develop the final network strength and durability.
Four common casting issues and practical solutions
1) Air bubbles / voids
Symptoms: pinholes, internal voids, reduced tensile strength, early failure.
Solutions:
Use vacuum degassing after mixing (especially for thick pours)
Maintain correct viscosity and pouring temperature
Keep molds dry and preheated when needed
Vacuum degassing and timing within pot life are frequently emphasized in processing guidance.
2) Short pot life / premature gelling
Symptoms: poor flow, incomplete mold fill, weld lines.
Solutions:
Select a system/curative combination with workable pot life for your part size
Control material temperatures (too hot often shortens pot life)
Use proper mixing efficiency to avoid local hotspots
Processing literature discusses how curative choice impacts cure rate and pot life, especially in different prepolymer families.
3) Moisture-related defects
Symptoms: foaming, bubbles, inconsistent hardness.
Solutions:
Store raw materials sealed; use dry nitrogen blanket if possible
Dry fillers/pigments; keep molds clean and dry
Note that different systems may show different moisture sensitivity during processing
4) Under-cure or inconsistent hardness
Symptoms: tacky surface, low strength, unstable compression set.
Solutions:
Follow recommended curing temperature/time
Consider post-cure to maximize mechanical properties
Ensure accurate ratio control and proper mixing
Why these process controls translate into better ROI
Better CPU processing means:
More consistent Shore hardness
Higher tear strength and abrasion resistance
Lower scrap rate and fewer customer complaints
Longer service life in wheels, rollers, seals, and wear components
Work with a supplier who understands production
Shandong Beiqiao supports customers not only with CPU material supply, but also with practical guidance on casting variables-material temperature, mixing, degassing, and curing-so you can achieve stable quality at scale.
Contact (WhatsApp & Email)
WhatsApp: +86 18853364460
Email: greilyn@beiqiao.net