๐ง๐ผ๐ฑ๐ฎ๐'๐ ๐๐ก๐ข๐ช๐๐๐๐๐ ๐ฆ๐ต๐ฎ๐ฟ๐ฒ : ๐ง๐ต๐ฒ ๐ฝ๐ฎ๐ฟ๐ ๐ณ๐ถ๐น๐น๐ฒ๐ฑ ๐ฐ๐ผ๐บ๐ฝ๐น๐ฒ๐๐ฒ๐น๐. ๐ก๐ผ ๐๐ต๐ผ๐ฟ๐ ๐๐ต๐ผ๐. ๐ก๐ผ ๐ณ๐น๐ฎ๐๐ต. ๐ก๐ผ ๐๐ถ๐ป๐ธ ๐บ๐ฎ๐ฟ๐ธ. ๐๐๐ฒ๐ฟ๐๐๐ต๐ถ๐ป๐ด ๐น๐ผ๐ผ๐ธ๐ฒ๐ฑ ๐ฝ๐ฒ๐ฟ๐ณ๐ฒ๐ฐ๐.
๐ง๐ผ๐ฑ๐ฎ๐'๐ ๐๐ก๐ข๐ช๐๐๐๐๐ ๐ฆ๐ต๐ฎ๐ฟ๐ฒ
๐ง๐ต๐ฒ ๐ฝ๐ฎ๐ฟ๐ ๐ณ๐ถ๐น๐น๐ฒ๐ฑ ๐ฐ๐ผ๐บ๐ฝ๐น๐ฒ๐๐ฒ๐น๐.
๐ก๐ผ ๐๐ต๐ผ๐ฟ๐ ๐๐ต๐ผ๐.
๐ก๐ผ ๐ณ๐น๐ฎ๐๐ต.
๐ก๐ผ ๐๐ถ๐ป๐ธ ๐บ๐ฎ๐ฟ๐ธ.
๐๐๐ฒ๐ฟ๐๐๐ต๐ถ๐ป๐ด ๐น๐ผ๐ผ๐ธ๐ฒ๐ฑ ๐ฝ๐ฒ๐ฟ๐ณ๐ฒ๐ฐ๐.
Then a small black charred mark appeared at the end of the flow path.
The defect wasn't caused by the plastic.
It was caused by the air.
When trapped air has nowhere to escape, it becomes highly compressed. The temperature rises rapidly, and the trapped air can ignite the surrounding polymer surface.
This phenomenon is known as the Diesel Effect — one of the most common causes of burn marks in injection molding.
Why does it happen?
① Trapped air at the end-of-fill region
② Poor or insufficient venting
③ Excessive injection speed
④ Vent locations that cannot evacuate compressed air effectively
How can it be prevented?
✓ Improve mold venting at critical end-of-fill zones
✓ Optimize injection speed to reduce air compression
✓ Design geometry that avoids air traps
✓ Validate air trap locations using Moldflow before tool steel is cut
✓ Maintain effective vent paths throughout mold life
Burn marks are not simply cosmetic defects.
They are evidence that the air inside the mold had nowhere to go.
๐ฌ Have you encountered burn marks caused by trapped air or the Diesel Effect during production?
What solved the problem—venting, gate relocation, speed optimization, or geometry changes?
Share your experience below ↓
source : IM Technologies
#InjectionMolding #BurnMarks #DieselEffect #PlasticDesign #DFM
#MoldflowAnalysis #PlasticDefects #Tooling
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