Recently infused three test panels inside one vacuum bag. All three panels were four ply. First panel was 3K 6 oz twill. Second panel was 3k 12 oz flat tow plain weave. Third panel was 12K 18 oz flat tow plain weave. The first panel full infused but the other two did not. The question I have is did the vastly different architecture of the materials cause the incomplete infusion? What other factors might have been at fault. 

I have never had a problem infusing Uni directionals, bi-axials, tri-axials, quad-axials or even 3D woven stacks, normally the thicker the laminate the easier it is. And have done the same in have wildly differing stacks in the same infusion.  Without seeing a diagram of how you set up your infusion it would be difficult to say exactly what was wrong, my gut feeling is that you had a leak at some point or the resin made it to you vacuum point before it had fully wet out your stacks.

Far UK