Can anyone ID this for me?

[Qanalyist]

This is pbt/gf looks like the glass is present but not the PBT, anyone know what causes this?
102102

[Qanalyist]

Bigger view
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[Qanalyist]

Bigger view
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I should add this tubular part is about 12mm in diameter and 1.9mm wall thickness and is an elbow type fitting 50mm x 40mm approx.

[rickbatey]

I see two causes:1-Poor venting at end of fill. 2-Too cold mold/melt temp or too slow of a fill rate causing loss of melt pressure at the end of fill. This is in the as molded state? Correct? I guess I should have asked that question first!
Rick.

[Qanalyist]

I see two causes:1-Poor venting at end of fill. 2-Too cold mold/melt temp or too slow of a fill rate causing loss of melt pressure at the end of fill. This is in the as molded state? Correct? I guess I should have asked that question first!
Rick.

Yes, as moulded. The rest of the part is good quality, what we would expect, just this inner feature is failing. The mould core is used for this feature and is a dead end with no vents.
This is what it should look like. This was moulded by the makers of the mould, so they did it somehow.
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[rickbatey]

Do you have their process data sheet? I still suspect your too low on the melt and mold temps and possibly compounding the issue with a slow fill rate. The hotter mold will bring the PBT to the surface and help bury the glass. What's the actual melt temperature?
Rick.

[Suhas]

I think Rick is on the right track on this. Vents, Vents, Vents - there can never be too much venting.
Suhas