Help with bubbles in Nylon parts

[atremblay]

We're seeing bubbles in our Nylon 12 parts. We're able to force most if not all of them out of the actual parts but they still always remain in the sprue. Any ideas of what's causing them? We're sure the material is well dried so it's likely not moisture.

[Pilot]

Hello,
the main question is what the bubble is - pressed air or vacuum? I suppose, that ithe bubble is based on vacuum. In the sprue it is "normal" because you have a thick material and during cooling you have a shrinkage. If the bubble is only in the sprue, is nothing to solve :-) or???

[Coryhoeppner]

A bubble in the sprue in your situation sounds like it is a void and not a bubble.

[Crabstix]

Post some pictures