Cisnerjo
Aerospace
- Nov 17, 2010
- 18
Hello,
We are experiencing some low results on our mechanical drum peel test coupon, our drum peel test coupon is made using two plies of epoxy prepreg (7781 style fabric) on each side of the core which is .210" thick. We noticed production people uses several ways to build them, customer specification does not specify anything related with plies orientation or core thickness so it was noticed that some people build the test coupons placing all plies (warp face up)on the same direction always making sure the prepreg plies with predominant fibers (7hardness weave) run against the core run ribbon direction, while some others run the top and bottom plies with the fill face up and only the warp face against the core ribbon direction, checking the lab results both are pretty much the same but does any of you know any real or valid procedure to build a test coupon for drum peel purposes. I found on the internet an example which it mentions the skins against the core must run with predominant fibers against ribbon direction but don't know what about the top and bottom ones, should they run the same as the plies that are located against the core? or should be balance and be run with certain orientation in order to obtain better drum peel results? How can I improve our results? test coupons are Oven cured.
I'll Appreciate any advice or support on this matter.
We are experiencing some low results on our mechanical drum peel test coupon, our drum peel test coupon is made using two plies of epoxy prepreg (7781 style fabric) on each side of the core which is .210" thick. We noticed production people uses several ways to build them, customer specification does not specify anything related with plies orientation or core thickness so it was noticed that some people build the test coupons placing all plies (warp face up)on the same direction always making sure the prepreg plies with predominant fibers (7hardness weave) run against the core run ribbon direction, while some others run the top and bottom plies with the fill face up and only the warp face against the core ribbon direction, checking the lab results both are pretty much the same but does any of you know any real or valid procedure to build a test coupon for drum peel purposes. I found on the internet an example which it mentions the skins against the core must run with predominant fibers against ribbon direction but don't know what about the top and bottom ones, should they run the same as the plies that are located against the core? or should be balance and be run with certain orientation in order to obtain better drum peel results? How can I improve our results? test coupons are Oven cured.
I'll Appreciate any advice or support on this matter.