Fiber-reinforced resin prints - how much STRONGER are they?

Can we create DIY fiber-reinforced parts on a normal resin printer? What materials other than carbon fiber cloth and glass fibers can we use? Does it make the parts we produce actually stronger? Let's find out!

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[nerdicorgi]

Concerned about the methodology here... There is a huge difference between Tensile Strength and Flexural Strength, and this test (which is purely flexural) is kind of a worse-case scenario for the orientation of the layers and the direction of force, mechanically speaking. I'll ramble a bit but don't want one wall of text so...




If I could recommend one improvement it would be to print two eyelets in your test pieces and do a Pull Test in a similar orientation to your scale. This would be testing Tensile strength instead of Flexural, and I suspect you'd find the overall tensile strength greatly improved over the default resin. When working with material composites, orientation is everything. To put into other terms: imagine a wet rope gets frozen all the way through. The newly rigid rope might, under the right circumstances, break if set parallel to the ground and force is applied to one end, as it's being attacked in it's thinnest/weakest dimension. If, however, the frozen rope was used to lift a load (as a rope realistically might be asked to do), failures in the ice may be more numerous, but they should be overall smaller, more evenly dispersed, and overall less impactful on the rope itself or it's ability to lift the attached load.

[JossWhittle]

Please wear a respirator when working with glass fibre, especially when you have frayed edges and you are making cuts.

[PaulDominguez]

CNC Kitchen should repeat this. We need multi site validation of results. Also the standardized test machine with replicates and standard deviation appeal to my inner scientist

[laukan]

I liked the print head bouncing in sync with the beat of the music 😁

[soliduslabs]

We add 10% milled 1/64" glass fibers to the resin by weight, it works great.

[IEleMenTIx]

Truly, a great idea! And definitely something to keep an eye on. Below I gave you some suggestions, based on my composites experience:

I think there were two main possible problems:
1.) Compatibility between the UV-resin and the glass fibres might be very poor. You would need to check the compatibility between the applied glass fibre silane-sizing and your matrix material. Sizing compositions are usually proprietary, so this is really hard to find out. I suspect that most UV-resins cure by radical mechanism, so a vinylsilane or methacrylsilane (or even Volan cloth) might work best. If, for example the fabric had an aminosilane applied, there is a chance that it would not react with the UV-resin.
2.) Impregnation quality could be poor. We do not know if the resin has fully wetted the reinforcement. There might be large voids within the fibre bundles, since no pressure was applied to compact the reinforcement layer and push air out. Looks like it at 7:32. Usually the individual fibre-bundles should appear almost invisible when properly impregnated. Maybe your cleaning agent at 6:27 has soaked into the fibre-reinforced parts prior to curing, which could cause a lot of problems.

10:50 and 14:06 The main failure mode looked like debonding and delamination, rather than fibre fracture - which would strongly agree with my theory. Therefore, the potential of the fibre reinforcement was not even closely exhausted. A continuous fibre-reinforced part must be both stiffer and a lot stronger than pure resin (thats common knowledge). A well-engineered fibre-reinforced composite usually fails in catastrophic manner. Here, the roving-reinforced composite failed by gradual delamination/debonding

[Hunterstoneking]

Maybe it would also be good to test the orientation of the fiber weave as well? Alternate the layup 45° each layer perhaps? Great work as always!

[Rob_]

Great video. I actually use reinforced fibers a lot, we build bicycle frame, velomobiles (sometimes called "banana bike") and special bicycle components. We use glass, carbon and kevlar for this. Strength depends on the type, thickness and weave of the material but even more important are the resin/fiber ratio and how compact the end result is.
Carbon is way stiffer than glass and kevlar is almost like a rubber band. Kevlar is mostly used in combination with carbon to prevent it from shearing apart on impact.
When using fibers, we always apply pressure to the end product either mechanically (by pressing the resin/fiber product in a 2-part mold), using vacuum (by placing the resin/fiber product in a bag and vacuuming all the air out or by applying pneumatic pressure (the product is made in a mold and the core is a balloon that is blown up to a few Bars of pressure). In this way the weave is pressed together and the layers are pressed on top of, partly into, each other. For us a 70% fiber ratio works best, so the product contains about 30% resin, but sometimes we make carbon sheets of 8-10mm thick that contain even more fiber. If you tap on that material with a hammer it sounds like a ceramic tile and it is very hard (does not flex at all) whereas for most things (like a bicycle frame, a steering bar or a front fork) you do want some flex.
The type of resin is also very important. Some resins are very brittle whereas other resins have more flex. A brittle resin with too few fiber content will result in the resin cracking up and the fibers shifting with tears and cracks in the fibers as a result. A more tenacious resin with a carbon/kevlar mix will end up like spring steel; hard to break, very flexible and very durable - this is even used as spring leaves by some companies.

I like to see what happens when you use short cut up fibers as suggested by another user too. We use 0.1 - 0.3mm glass and carbon fibers as fillers and those are mostly used in combination with glass bubbles and cotton fiber. The carbon or glass will add strength, the glass bubbles make it flow more easy and the cotton fiber make it thixotropic.Cotton is not suitable for 3D resin printing but mixing small fibers or glass bubbles is something that could be worth a try

[joeldriver]

I think 3D printing a mold and just making an epoxy/glass part would be easier at this point. Very cool tests!

[pablo]

Nice video! Another reason why the strenght of the reinforced samples is not very high could be the fact that the printing resins do not adhere to the glass fibers like epoxi or polyester resins do. To transfer the external load that is applied on the resin to the fiber, a chemical bond between resin and fiber is needed. A specific resin designed for fiber reinforcement could get better results.

[rdIsBest]

Interesting application towards engineered composites. Generally fiber composites have a resin volume fraction of 30% or less, and you'll only see improved strength and stiffness if the raw fibers are themselves stiffer and stronger than the matrix (maybe why the random orientation drywall fibers failed)

[christopherenoch]

This was a great idea! I've not seen anyone else on YouTube do this. Great video and I can see this technique gaining popularity. Thanks Tom.

[Trenchoat]

I think the reason the more coarse weave works is that those layers have holes/gaps where the resin can connect between layers. With the glass fiber paper, you create a total break inbetween each resin layer. So you loose some of the effect of it being a composite material?

So trying the paper again with holes or lines cut in would be very interesting.

[aronrad]

Looove the editing! @3:15 printer disco? Yes please!

[chicoriver]

I was FRP inspector for years use the RTP1 book as a guidance and astm for pipeping will give you the right amount layers of material to have the desirable strength. Roll out the material first make sure that air is out for max strength with the same resin then 3d print on top of that. Do a tensile test, barcole test and a burn out to see how strong is your compositive. Like your show I do 3d print as a hobby. Thanks for your dedication.

[scottre]

I have thought of doing this for some time but I was thinking of mixing the separated fibers into the resin so the print would just run with no pauses. Would be interesting to see this if you can do it (may be messy?).

[jlucasound]

Thank You for performing these experiments. Reinforcing resin prints is what is on my mind.

[MakenModify]

Hm... on plastic (and filament) shredded fibers are often used. You could try those, but should be a similar result i guess. Great video 👍

[_djengis]

Better than any netflix documentary. Nice editing. Nice shots. Nice music sync. Deep and experementary infos. Really gread vid.

[t_c]

Could you try unidirectional fiberglass strands knowing your bending load.

Also could you try small chopped fiber just mixed into the resin?