How to Make Carbon Fibre Foam Sandwich Panels
2021 ж. 18 Сәу.
109 994 Рет қаралды
Formula Student Oulu team members showing how to make carbon fibre sandwich panels that are both light and strong.
All of the fibre equipment, ie. epoxy, fibers, and the different layers were sponsored by Kevra / Kevytrakentajan verkkokauppa.
If you need any of the fiber manufacturing equipment used in the video go check out www.kevytrakentajanverkkokaup...
We get our core foam from Finnfoam, we currently use the XPS-400 type. www.finnfoam.fi/
The glass pane was provided by Lasi Lipponen www.lasilipponen.fi/
Our Instagram: instagram.com/fsoulu/?hl=en
Our website: fsoulu.fi/
Music by: instagram.com/jan1leva/?h...
I really love your foam cutting system.. the step that define the thicness is wonderful
Use rohacell for your core. Cut your fabric larger than you need. Pull a thread out along your cut line to give a cutting guide. You can get way better material properties/fiber resin content if you oversaturate your cloth with epoxy then prebag it for several minutes with peel ply on both sides which will pull out 100% of excess resin
Rohacell is wayyyy overkill for most applications and very expensive. Crosslinked PVC foam such as Airex will do the job at a much lower price. Keep Rohacell when you need temperature resistance above 120°C and best in class modulus / strength are necessary.
@@SuperYellowsubmarin in industry the cost of to manufacture a composite part treats the material costs as near negligible. When you’re making a multi thousand dollar part $100 of core cost doesn’t matter.
@@danielcockerspaniel I work in the aerospace industry and the cost of composite material can amount to near half the finished part cost !
@@SuperYellowsubmarin I also work in the aerospace industry and an entire roll of prepreg IM carbon is
@@danielcockerspaniel light aircrafts (FAR 23) are quite cost critical. Commercial aviation and military favor high performance and specifications over cost.
what is the bulk density of XPS? This feature is not listed on the manufacturer's website. The XPS commercially available in Russia often has an overestimated surface pressure, so it is better to navigate by bulk density.
In the last seconds the assembled frame of a wing is visible. How was it's surface made?
I saw this pizza cutter wheel-type cutter for carbon recently works so easily, just roll over the carbon once and snip the kevlar strip at the edge with scissors. It avoids putting kinks n the weave as you cut. Another trick is to paint the layer under the fiber black, this way anywhere there is a slight gap between fibers gets hidden.
What sealing tape are you using?
Great video! I use the same idea instead of buying over rated foam cores (can not believe the price on these things, and shipping). What tape are you using? It looks more economical to the yellow tape I'm familiar with. Epoxy is great! It will stick a ton to anything. Still, try to get release agents away from the intermediate layers. The effects of having silicone or wax in the mix may not be obvious, because, well, epoxy is great at sticking to things. However the bond is a lot weaker when release agents or wax are present. Wet layup is perfectly fine. As a matter of fact, it's probably better than infusion in this case, since it will limit epoxy seeping into all the cavities in the foam (I know it's closed cell). Someone suggested using microballoons. I think it's a great idea to level the surface of the foam before layup. Again, great video.
how strong can these panels be?
Doesn't the wax transfer from the glass to the bottom of the core foam and prevent epoxy from sticking to it?
Good point, so far we haven't experienced wax transferring from the glass to the foam but it might be a good idea to work on the panels on some other surface than the waxed glass as a precautionary measure.
Wax transfer isn't a huge deal unless you are literally rubbing the foam around that surface
what's the most efficient way to seal the edge so the PMI foam is not exposed to the air?
We are currently investigating that. So far we've considered, rubber u-profiles, wet carbon fibre cloth, duct tape, and just putting epoxy on there but we aren't sure about what is the best way quite yet.
How we do it on high end composite craft: cut out a given depth of core with a router bit , mask the outside edges of the skins, and backfill the rabbet with thickened epoxy.
Music was fine, can’t please everyone. cool video
What do I do if I want to cover the exposed bits of foam? Do I just cut a bigger piece of fiber?
So far it seems that a frequently recommended solution for this is to compress or carve away a bit of the core on the edges with for example a flat head screw driver and then apply some thickened epoxy into the resulting gap. Sand the result if needed. We haven't tested this yet and last year we got by by just using black duct tape to seal the edges, this wasn't a very good solution and we will definitely try the epoxy solution next time.
Hi guys ! Thank's for this video, very technical. However, could be king and give me the name of the music record you use (very good). Thank's in advance. Have a nice week.
The artist's Instagram is linked in the video description.
The first coat on the foam should be with microbaloons added to the mix, otherwise you'll have pure epoxy filling the cavities of the foam, increasing the weight of the sandwich without adding strength. Working on the waxed surface is bad form. You'll contaminate the foam, causing tiny delaminations as well as scraping up the wax film.
If you're using vacuum anyway, you'll get a lot nicer results with infusion.
This sounds like a very good idea actually. I haven't tried this yet but I did have a hard time with epoxy seeping into the foam.
Did you use just one layer of fiber on the core? I'm trying to see if my smaller build can get away with 1 plain weave ply on each side, without including the unidirectional fiber layer on insider ply layer. It'll be a somewhat large speaker cabinet, with theoretical max weight on top of 500lb. In practice, much less weight.
It depends on what you use your panels for. We mainly subject our panels to bending loads and want them to be light so we tend to make them a bit thick and with only one ply of 200g fibre. For your application where weight is not an issue and you are putting a lot of weight on top of the panel like that you might want two or more layers. I suggest you do some strength calculations, see what cross section you need to keep the stress down with that 500lb.
@@formulastudentoulu3665 thanks. going one unidirectional for vertical strength with another weave on top for any theoretical shear, on both sides of 4lb density 1/2" foam. likely only 50lbs on top of it, but assuming if anyone sits on it sorta thing.
@@labrandons Yeah that sounds fine. Just make sure that you are able to bond the corners of that box together well since otherwise it'll just fold like a house of cards.
@@formulastudentoulu3665 thanks! I have a really nice and easy dovetail jig and considered dovetail together with adhesive. I know 3M makes a nice composite adhesive, and will probably also thicken up resin to bind corners along with brackets as a fail safe.
Always use perforated release film. Always make holes(or use perforated foam).
Hey, We are using the wet layup method so we don't need perforated or channeled foam like you would with the infusion method. Though admittedly there seems to be a fairly significant improvement in properties of the panel with perforated foam according to papers I've read. We also haven't really seen any need to use perforated release film since we already have the peelply layer. Though we do use the film for surfaces that need to look good.
@@formulastudentoulu3665 Hi! You will drastically improve the quality if your parts (first of all mechanical) if you use holes in foam. Try to peel the laminate from perforated foam and from not perforated. Perhaps I.m wrong, but anyway you can make a interesting video 😜 Release film helps you to obtain good ratio of resin/fiber first of all. With your method resin runs away to bleeder, making laminate too dry, release film regulates this ratio and helps to compress laminate. You can eliminate it during infusion, but it is mandatory with wet lay up.
@@user-fm1rh3ht4v It's totally true that the peel strength will be improved with perforated foam. Honestly there are so many different factors and force scenarios with these sandwich panels that it could make your head spin 😅 I wonder about the resin percentage part as well. So far we haven't noticed a very big difference in resin percentages between just peelply and bleeder film + peelply but that is certainly a thing we will keep an eye on in the future since you mentioned it.
@@formulastudentoulu3665 Hi! In real life the wet lay up is made with "applicator", axillary double film. We put carbon on film, soak it with resin, spread resin by spatula, then cover carbon by second film and squiz excessive resin by spatula. Then we remove one film, apply carbon and then remove second layer of applicator. It is quite convinient for biaxe. Especially on complicated surfaces. So we don't have too much resin in carbon layer. So if we apply enough (not too much) of resin on carbon and then apply dry bleeder, resin will spread evenly on all laminate (carbon+bleeder) so if carbon layer is thin, bleeder will make carbon too dry. You need pour much more resin in order it is enough too make wet either carbon and bleeder. Perforated film prevent this situation. And last, but surely not least😀 If you make complicated surface, use good resin and hot cure, you will never remove bleeder without release film. It will become a part of your work for ever😀.
How are you going to keep the fabric from having an inprint of the perforations? This might be okay if you use premade CF panels to bond to the foam.
Why didn't you guys just vacuum infuse it? Much better reinforcement to resin ratio it would seem.
We use wet layup due to the somewhat lower costs and because it's a process we have experience on. We have considered moving on to infusion but haven't yet. Also, isn't there just something beautiful about how simple wet layup is 😉
What is the process name ?
The object you created looks like some type of chassis, is that correct?
In picture there is our rear wings 1st element inner structure containing ribs and spars, so kind of a chassis. We have also used this method on multiple different places like floor, dashboard and steering wheel.
@@formulastudentoulu3665 I wanted to build something similar to a Velomobile and the F1 monocoque method seemed like my best way to do it but I'm barely grasping the basics. How do you use ribs and spars in your Floor?
@@olivercarlin2650 We use ribs and spars only for wings, I meant we use panels cut to shape for our floor. We have a tubular space frame.
wouldn't Gator Board be a better substrate?
Hello, It could be, but XPS board is cheap and it works for us because it's very lightweight. If you are making your own project use what's available for you and suits best your needs. There's all kinds of fancy core materials, but they are quite expensive.
@@formulastudentoulu3665 I get it, budget is a big factor in engineering. Not sure what the brown exterior top and bottom layer are in Gator board but that are way stronger than the paper in foam coar and still very lite weight. Sadly Gator board is pricey.
@@othoapproto9603 One thing to consider also is that the paper on top of that sort of board probably doesn't do a whole lot since we are adding carbon fiber there anyhow which is way stiffer than any paper. Foam characteristics are the important thing.
@@formulastudentoulu3665 Have you used Gator Board before?
@@othoapproto9603 I haven't, I just googled it and it's a wood fibre backed foam board, right? Seems like a pretty smart idea for an easy to produce, inexpensive, and easy to dispose of light weight but still fairly rigid foamboard. They use extruded polysterene as their core foam, just like we do so our boards are kind of like Gator boards but with carbon fiber instead of wood.
good music
Why do the vast majority of you tubers believe that technical videos need aggressive music that’s loud. The music might be acceptable if it was extremely low. However, the vast majority of viewers are tuning in to learn and the music is just a mental barrier. I would much rather hear a narrator explaining: development thought processes, issues to avoid, problem-solving, pricing issues, quality issues, Along with other applications etc. Just some thoughts my friends… Good job on the project.
Thanks for the feedback. This was our first "how to" style video so it might be a bit rough around the edges with stuff like audio levels and whatnot. However we are already planning our next video and we are considering adding narration to that so stay tuned!
Good thing your device has volume control
Tend to agree , less aggressive background music. Can’t fault people for trying though . In my experience of rear aero foils a good way to make them is us pultruded grp tubes down the length one on the leading edge and maybe 2 at the thickest profile / another near the mounting points . Their very light and strong . Wire cut foam cores then wet lay / vac bag . Not forgetting that stresses on the top / bottom skin will be the opposite of one another and this need to be taken into account when laminating . Nice to see people having a go , hats off to you , good luck 👍
Feel free to turn down the volume and comment on their content instead...
Heu what is the material used for panels is it m.d.f
Hi, It's XPS insulation foam board, we currently use finnish brand finnfoam, but there's many similar products available all around the world.
look at that fookin link at the end
What's wrong with the link? All links are in description also
@@formulastudentoulu3665 I think he means that to non-Finnish it looks like a massive crazy string of random letters
luky if all went on first atempt.
We have tested many different methods of making carbonfiber panels and this has been the best. After many hours of testing and reading online we have gotten to satisfying level with our work so we decided to share it to everyone! But definatly not our first attempt ;)
Ditch the music. After a few minutes of listening, I felt like buying a wig and becoming a head banger.
Thanks for the reply. We appreciate that you checked our video!
watch on mute while listening to your own tunes
@@SuperDodoe Sound advice!
In the text you say you use twice the resin to cloth by weight, at the end you have 65/35% glass/resin. It would seem like a very expensive way of producing a panel wasting that much resin. Why not use resin infusion?
I haven't had to mute a video in a long time. So long, in fact, took a second to figure it out. Great job on everything EXCEPT the music.
These methods produce really heavy panels.
background music, you need to fuckin chill bro
Uhh, you can use cheap paper towels layered two to three deep as absorption material! Save money live better.
overly load music contributes nothing
Pointless video if you don’t explain what you’re doing.