Resin Rich between individual plys

[goyo0812]

This part is made by ATL machines using CFEP UD Tape
some parts have been rejected due to resin rich between individual plys after NDT inspection
I am trying to know how this issue happened though,
there was no any change in roller presure and No difference in bagging and cure process
Do you have any idea?
Someone told me that there would be some possibility that the contents of resin in raw material may cause this kind of resin rich

Thank you

 

[SWComposites]

How are resin rich areas being found by NDT? Where did the accept/reject criteria come from? Typically it takes actual voids or porosity to show up in NDT. Have you cut up parts and photo'd cross sections to verify the condition.

Resin rich areas can come from material variations, low pressure in local areas ( bag bridging, tooling mismatch), etc.

 

[goyo0812]

The defect was found as FO(Foreign Objective)by NDT. after doing section cut, i relaized that the defect was NOT FO BUT Resin Rich

 

[Compositepro]

If the issue is not actually a plastic film liner left in the part, the cause would be a high resin content. If this is in a radiused area it could be due to fiber bridging where the gap between plies filled with resin.

 

[berkshire]

Check the tightness of the bag as the vacuum is drawn down, sometimes this can be caused by the bag material not being free to move over the surface of the layup. Bridging across corners is common when this happens.
B.E.

You are judged not by what you know, but by what you can do.

 

[SWComposites]

so just how thick is this resin layer? what percent of nominal ply thickness? is it in a flat area, or highly contoured area? concave or convex area?

 

[goyo0812]

about 4times compare to nomal thickness of resin layer between plys, Yes it is in a flat area
this resin rich occured over certain area of the entire area

 

[Compositepro]

A picture is worth a thousand words. In cases like this a picture will often immediately lead to an answer.