Laminate Sample #30: 6mm (0.25") Infused Carbon "Tooling" Plate
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- Опубліковано 11 гру 2020
- This Laminate Sample is an example of infused carbon /epoxy that could be used for high-temperature tooling for prepreg parts. At 6mm / 0.25" it is about a minimum standard thickness for not-tiny carbon tooling and is stiff enough to require minimal support structure with parts that have some compound curvature. Flatter tooling would benefit from more thickness - or in some cases core.
The Proset INF 114 epoxy used here is a stand-in for a higher Tg tooling epoxy that would give the potential for a service temperature above 250F / 120C. This would require post-curing to this temperature or so, which could be on-tool or as a mix of on-tool and unsupported, to enable less stable masters or plugs.
The fiber volume fraction is quite low - about ideal for carbon laminates. The only time you'd want lower is with prepreg uni - but even then - 58% fiber by volume is pretty good. This is equal to approximately 30% resin by weight for a 70/30 fiber resin mix.
Of course this could also be an example of a part laminate if you need something very rugged and uniformly strong in all directions. There are probably better ways to do this than solid carbon though - core is usually good, or at least some more "directional" engineering.
I am working on an article on infused high-temperature tooling at explorecomposites.com, and will update this description with a link when it is complete.
In the mean time, check out all the other articles and useful composites info:
explorecomposites.com/ - Навчання та стиль
Nice ! Tooling prepregs are terribly expensive so I also keep them for complex projects or where more durability is required. Actually, I even go to fiberglass (fabric then multiaxial just like you did) when CTE is not an issue, even to mold carbon fiber prepregs. I just tried "bag ports" from Eldon James, they make wonderful infusion hose ports, inexpensive, ultimately reliable seal, and do not stick to resin at all. You may want to try those !
Thanks for the lead on those bag ports - just looked them up and they look ideal - and cheap!
I too have used glass for small stuff or parts where the geometry doesn't care about a little mold movement. But there's lots of carbon out there and sometimes you can pick up surplus stuff cheap that's perfect for tooling - that's what this slit material was.
How would forged chopped tow compare to this for hard point mountings ?
And those white lines in the cross-section, is that the stitching? Ive seen them on monocoques.
Any idea on the resin consumption (waste) of that Enkafusion? Also hard to tell from clock/timelapse how fast the enkafusion really filled compared to the laminate. How far can the Enkafusion carry the resin before needing another input port?. Looks like you had 3 inch wide (probably overkill for your plate), I've got 2". My part is 18' long (and likely will need zones). Plan to use INF-114 so same viscosity.
I threw out the Enkafusion or I'd weigh it - it uses a fair amount of resin - maybe a 1/16" thick "bar" or resin the width of the channel. Yes, the 3" stuff was way overkill here - filled in maybe 10 seconds. It flows fast and far - maybe 10' between ports is doable if you have bigger feed lines - maybe more. Unless you use a coated peel ply, it sticks like crazy to the laminate - with nylon peel ply I have had good luck putting strips of teflon coated peel ply just under the Enkafusion so it releases ok.
so this brings up a question about peel plys. Most seem to be nylon. I've been using some Airtech Econostitch and have some Bleeder Lease B, and some Porous Teflon to do some testing with. Also got some samples from Pro-Vac. Very similar look and feel to the Econostitch. One was nylon, the other polyester. Any idea about why you would use polyester vs. nylon? Nylon won't stick to the resin - the bag film is nylon and doesn't stick and neither does the peel ply. I haven't tried the Polyester peel ply yet, but if you used it with polyester resin, you would think it would bond in. ????? Pro-vac is west systems, so maybe they expect that you would use it with only epoxy.
Why is it necessary to use spray adhesive between layers if the lay-up is completely flat?
It isn’t really but for heavy material with some set from being rolled it can help. Also good practice to make test panels in the same way you’d make parts.
what is that wire type thing on middle of setup?
That's a thermocouple to monitor temperature. I was going to go over postcuring and Tg and more temperature stuff for dealing with higher temp tooling resins. The video got too long - and I got lazy - and it's not something you can cover in a minute without being even more confusing!
May I ask what resin system you are using?
Proset INF 114 infusion epoxy
How does carbon compare to basalt for thermal expansion?
Carbon is better (lower) than basalt, but basalt is better than glass. I think the effective CTE for basalt is around 2 x 10^-6
/ °C where carbon is around or slightly below zero and glass is about 5 x 10^-6
/ °C. I am not 100% on these figures but the general idea is basalt has about half the CTE of e-glass. Might be a good thing to test!
@@ExploreComposites thanks, I’m starting on a new plug for a skiff next week, and will be making a mold in late January. Will be doing be & epoxy builds out of it. Seriously looking into using basalt for the first 1/2 of the laminate in the mold. I know it’s a great insulator so it should reduce the glass from expanding and keep the heat where I need it.
would you use a gelcoat on a tool made this way?
You could use a polyester gelcoat but it wouldn't hold up, and bonding to the carbon/epoxy would be problematic. A vinylester gelcoat with a glass mat skincoat would probably work (for a while at least - and only at low-ish temperatures) but isn't standard/good practice.
Most tooling like this either gets left raw like this and release coated or gets a gelcoat-like epoxy mold surface coating that gives a very hard surface and reduces the likelihood of print-through. The coating is usually applied to the plug surface and the dry infusion layup is done once it is semi-cured. The postcure gives everything an all-epoxy primary bond and things are good.
@@ExploreComposites
Thanks alot for the reply!
Im looking to do most plugs/masters using polyurethane tooling board and a cnc router and coat polish gloss using something like easy composites
S120 Advanced Board & Mould Sealer.
So the plug will be pretty much perfect. Previously I have always used a brush on vinylester and polyester fiberglass tooling system but I get air bubbles in the gel and other cosmetic issues with that some times. I dont have a spray system for the gelcoat.
Would this be a decent alternative to do it, if I use a single block of tooling board to keep the air leaks down?
@@johndiedrichs6155 If you need the low CTE for cooking carbon parts this is a great way to get it. If you're not cooking prepreg then this is way overkill!
You don't need a gelcoat, but it does make things more forgiving in terms of surface quality. Generally if you need a gelcoat finished part then the tool should be gelcoated - if you're building parts that get painted then a raw carbon tool surface is fine. You can use the same primer/sealer/release coat type system that you use on tooling board. If you envelope bag or bag the tooling block to a table, the leaks are less of an issue.
Have you see the article on the EC! site about tooling boards? There is a list of products for finishing tooling block - similar to the S120:
explorecomposites.com/articles/tooling/machinable-tooling-boards/
There's also an article on gelcoated production poly/VE type molds - might help with gel issues:
explorecomposites.com/articles/tooling/building-open-molded-production-tooling/
When I look at what we get for heavy fiberglass truck canopies and solid tonneau covers versus how much they cost, it makes me highly disappointed that techniques like this aren't used in their construction. Even if this would be significant overkill for such a part, it probably weighs a third of what the fiberglass ones weigh and as expensive as they are I don't know where the money's going besides company profits.
A big component in composite construction is labor! Most truck canopies are E-glass and the worst possible laminate layup, chop layup. That's where roving is cut and sprayed into the path of the resin shot out of a spray gun. The weakest possible laminate, not uniform, and relatively cheap. Even chop strand mat (3/4oz or 1-1/2oz) would be much stronger but the time would go up substantially in the construction.
It is entirely false to think that composite parts are over-priced. Injection molding and thermoforming have warped our sense of value...these processes make a part in minutes, whereas a fiberglass or carbon fiber parts will occupy a mold for a full day. Manufacturers do everything they can to speed up the process to cut costs, but if anything they struggle to make a modest profit.
This might be overkill! And you'd be surprised how expensive a layup with all these plies can be. Labor is a huge consideration for composite manufacturing unless you are in the very high volume fully automated situation. The material in this sample alone is $35-45 per square foot - so over $1000 just in materials for a 30 square foot panel. And it'd weight 60+ lbs!
Can you machine this piece?
It would machine nicely with the right cutters. I have machined many similar pieces...