|
Zeyad Gamal
|
|
|
Group: Forum Members
Posts: 17,
Visits: 118
|
We are infusing a small flat sheet as shown in the picture but we keep running into a problem with the infusion using a lot more resin than expected. We are using 2 layers of 200gsm CF with 10mm easycell infusion grooved foam in between. We estimate that for 1 sqm of the laminate, we will need 400 grams of resin (for the 2 layers of 200gsm CF) plus another 700 grams for the infusion mesh, with an extra 100 gm for the lines. The infusion starts nicely and at a decent speed, but the problem is that the resin runs out with 50% only of the part infused or even less. We eventually had to put 3 times more than amount we calculated until the resin finally reached the vacuum port. This resulted in the part weighing twice as much as expected which is unacceptable as this is a very weight critical application. What are we missing here ? this also happened with another part that was around 4 times bigger and we had the same issue. We did vacuum tests and by the time we opened the part the bag was very tight so we don't think it was a leak issue. We are using peel ply between the bag and the laminate at each side and a layer of infusion mesh on the top part of the laminate. 
|
|
|
|
|
leeks
|
|
|
Group: Forum Members
Posts: 7,
Visits: 3.7K
|
You're missing the resin uptake on the foam core.
I'd estimate that specific core to be around 500g m2 per side. Or 1kg m2 total.
200gsm carbon = 135g m2 /layer of resin
pvc core with infusion groove and holes 1kg m2 of resin
mesh 350-700g m2 of resin depending on type
hose 50-100g per metre depending on diameter
plus a little left in the pot!
|
|
|
|
|
Zeyad Gamal
|
|
|
Group: Forum Members
Posts: 17,
Visits: 118
|
+xYou're missing the resin uptake on the foam core. I'd estimate that specific core to be around 500g m2 per side. Or 1kg m2 total. 200gsm carbon = 135g m2 /layer of resin pvc core with infusion groove and holes 1kg m2 of resin mesh 350-700g m2 of resin depending on type hose 50-100g per metre depending on diameter plus a little left in the pot! It was stated on the product description page that the foam has almost no resin uptake, that's the main reason we are using it, so it's very surprising it would absorb that much resin. Also, the foam is grooved on the lower side only, does that affect your estimation?
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Yeh the foam itself does absorb very little resin, it is closed cell so it is only the open cells on the face of each side of the foam that absorb resin - which as the manufacturers claim is very little.
However the grooves and holes absorb a hell of a lot. Leeks is pretty bang on with his estimate, I would agree with him. Infusion with core materials just isn't a great option for really weight critical parts.
|
|
|
|
|
Zeyad Gamal
|
|
|
Group: Forum Members
Posts: 17,
Visits: 118
|
+xYeh the foam itself does absorb very little resin, it is closed cell so it is only the open cells on the face of each side of the foam that absorb resin - which as the manufacturers claim is very little. However the grooves and holes absorb a hell of a lot. Leeks is pretty bang on with his estimate, I would agree with him. Infusion with core materials just isn't a great option for really weight critical parts. Yup that's true but we had very little choice as most materials are shipped internationally so prepregs are a no go. We are planning to use 2mm Soric for an upcoming project, as I understand it should have about 1 kg of resin uptake per sqm, is that right ? I'm just worried we might end up with another surprise.
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Yes Soric is also heavy. About 550g per m² per mm thickness. So yeh, a 2mm thick core will consume about 1100g of resin per m².
I purchase pre-preg internationally from Easy composites, I believe they can supply most of the world without issue. Their XC110 has an out-life of 1 month (actually lasts longer in my experience) and they deliver to me in Australia within 3 days, so that's no issue.
Another option is to do it in a 2 or 3 shot process. Do you have to infuse it all in one go?
|
|
|
|
|
Zeyad Gamal
|
|
|
Group: Forum Members
Posts: 17,
Visits: 118
|
+xYes Soric is also heavy. About 550g per m² per mm thickness. So yeh, a 2mm thick core will consume about 1100g of resin per m². I purchase pre-preg internationally from Easy composites, I believe they can supply most of the world without issue. Their XC110 has an out-life of 1 month (actually lasts longer in my experience) and they deliver to me in Australia within 3 days, so that's no issue. Another option is to do it in a 2 or 3 shot process. Do you have to infuse it all in one go? From my experience shipping already takes 10 days to Egypt, and because this is a college project funding is not always consistent, so we have to buy the stuff much earlier than we need them. Doing the part in 3 shots is the only alternative, but it's time consuming, because we already have to infuse at least 4 times so we'll definitely run out of time for the competition.
|
|
|
|
|
MarkMK
|
|
|
Group: Forum Members
Posts: 338,
Visits: 2K
|
As the part looks fairly small, could you not infuse a flat panel big enough to cover both sides of your intended foam core and bond these around it? Shouldn't be overly time-consuming and the only excess resin would be that used to coat the back of the infused panels and/or the foam core. You could then look to use foam without the added channels
|
|
|
|
|
Zeyad Gamal
|
|
|
Group: Forum Members
Posts: 17,
Visits: 118
|
+xAs the part looks fairly small, could you not infuse a flat panel big enough to cover both sides of your intended foam core and bond these around it? Shouldn't be overly time-consuming and the only excess resin would be that used to coat the back of the infused panels and/or the foam core. You could then look to use foam without the added channels That would have been ok with this part for sure. For the remainder of the parts they are more complicated and larger, also, the remainder of the parts will include a mold and will require larger vacuum bags and mold preperation
|
|
|
|