Extrusion & Post
7 views
PMMA Extruded Sheet Stress Streaks
Problem Phenomenon
Sheets show stress streaks under polarized light, and crack along the streaks during hot bending or engraving.
Cause Analysis
Mismatched extrusion haul-off and cooling freezes orientation stress in the sheet; too-low roll temperature and too-fast haul-off both increase residual stress.; During on-site troubleshooting, verify item by item according to this mechanism to avoid blindly adjusting the machine based on experience alone.
Solution
①Optimize three-roll temperature matching; ②reduce haul-off stress; ③anneal sheets; ④test stress distribution before processing.; After adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability.
Key Takeaway
The internal stress of extruded sheets affects secondary processing safety; stress testing and annealing are necessary preparations before further processing.; After confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence.
Was this helpful?
0 people found this helpful
Thank you for your feedback!