Carbon Fiber 3D printer

The MarkForged 3d printer prints Carbon Fiber. initially desgined to build F1 body parts. I am no way affiliated with Mark.

That's awesome! I would totally buy that. I wonder how he prints the CF, since typically it needs to be soaked with some kind of epoxy then vacuum sealed.

---

greghoge.com

HUGE 3D PRINTER PARTS SALE!!!

Looks like a nice dual extruder setup with the carbon fiber as the infill and nylon as the outer shell. I don't think the resolution would be good enough to use without a dual extruder. It's a pretty a unique approach, but I bet the carbon fiber filament is very proprietary. It's a shame, because it looks like most large nozzle extruders could probably handle it's extrusion.

Quote
gmh39
That's awesome! I would totally buy that. I wonder how he prints the CF, since typically it needs to be soaked with some kind of epoxy then vacuum sealed.

In mass production settings, carbon fiber comes in "prepreg" weave, where the manufacturer soaks the material in a special epoxy formulation that doesn't harden until heated in an autoclave (under vacuum) per a specified ramp temperature time/curve chart. Many need to be kept in a refrigerator for long-term storage. The benefit is that you can get the best carbon-to-resin ratio this way, and it is easy to lay out in molds.

From the cutaway picture, this printer appears to be laying down a continuous carbon fiber yarn/filament, like a filament winder for making CF tubes. With some sort of continuous prepreg CF yarn/filament being heat-triggered by the extrusion nozzle, it doesn't seem implausible to lay a *continuous* bead of CF yarn/filament down with a little tweaking to a 3D printer.....

Quote
vreihen

Quote
gmh39
That's awesome! I would totally buy that. I wonder how he prints the CF, since typically it needs to be soaked with some kind of epoxy then vacuum sealed.

In mass production settings, carbon fiber comes in "prepreg" weave, where the manufacturer soaks the material in a special epoxy formulation that doesn't harden until heated in an autoclave (under vacuum) per a specified ramp temperature time/curve chart. Many need to be kept in a refrigerator for long-term storage. The benefit is that you can get the best carbon-to-resin ratio this way, and it is easy to lay out in molds.

From the cutaway picture, this printer appears to be laying down a continuous carbon fiber yarn/filament, like a filament winder for making CF tubes. With some sort of continuous prepreg CF yarn/filament being heat-triggered by the extrusion nozzle, it doesn't seem implausible to lay a *continuous* bead of CF yarn/filament down with a little tweaking to a 3D printer.....

That makes much more sense. Im just used to using carbon tow that needs an epoxy resin for things like bamboo bikes.

---

greghoge.com

HUGE 3D PRINTER PARTS SALE!!!

Why is MarkForged not showing how it works, maybe there are bugs to work out?

The web site states that it's a Patented Continuous Filament Fabrication.
I didn't find a patent, maybe they have a licence.

I did find a reference to MIT on the aeromotions web site, and
Gregory Mark is a graduate of MIT, and MIT is big on patenting 3d printing.

It looks like a braid, maybe it's a tape, or is it printing a core, then wrapping the carbon fiber around it?

I don't see a reference to epoxy, so it's possible they are using some thing like a modified/filled cyanoacrylate.

Prepreg's are very expensive, need to be refrigerated, and have a limited shelf life.

The title says it's printing the support for a wing, not the wing.

From my quick perusal, it is using standard FDM with a special filament. this feels like a marketing ploy so that they can say "CARBON FIBER". sure, it will be stronger than typical pla or abs or whatever, but it's still got the same issues with inter-layer strength, i assume.

I feel like this is similar to mixing powdered steel into abs, and then saying you can print steel.

Who will be the first to mix soot into filament and sell it as nanotube filament?

Edited 2 time(s). Last edit at 01/29/2014 03:02PM by Buback.

From looking at the sample print, my eye is immediately drawn to the top right corner, right where the flat edge ends and the curve begins:



It looks to me like the printer put down a continuous yarn/string winding of CF and sandwiched it between a printed nylon core and printed nylon outer skin, and the spot that I'm seeing is the point where the yarn ended in the winding process. Perhaps the simplicity of the process is why there are no details on the web site?????

Quote
Buback
it will be stronger than typical pla or abs or whatever, but it's still got the same issues with inter-layer strength, i assume.

Introducing fibres into materials make them stiffer not stronger, any extra strength comes from the fibre itself not the base polymer, for them to be successful you have to "wet" the material, which is quite difficult to do in thermoplastics ABS or PLA because of their viscosity, but easier to do with thermosets, the key to solving interlayer adhesion could be to print cross layers as they do with aircraft wings etc, this is nothing new and I can see 3d printers could be adapted to do it small scale easily. You can buy both CF and GF in various sizes it looks like shiny string. I am wondering if its possible to just feed it through an enlarged nozzle and let it be drawn through with the melt flow, or would it need to be coated in the thermoplastic first, like electrical wire, where the copper is the CF/GF with a Nylon, or ABS sheath.

Regarding patents, i don't think MarkForged will get a patent granted, its all been done before, certainly I will be objecting to it, see Ron Hawley's US Patent number: 4439387 explains it well, and you can clearly see the similarity to a 3D printer head.

See Neil Cogswell of ICI and Ron Hawley of Polymer Composites Inc who developed long-fibre reinforced nylon and PP in thermoplastics.

See The Drostholm continuous pipe process developed in the 50's if you study this patent it will show you filament winding where a continuous fibre, coated with synthetic thermoset resin, is laid down onto a mandrel.

---

# 500

I am wondering if there is a cutter of some sort built in to cut the CF and allow transition to the nylon extruder head.

---

# 500

hi guys please tell me that for using a carbon fiber for 3d printing ,what kind of extruder must be used if anything please suggest me guys, thanks in advance

Well, 8 months later and the printer is still in pre-order... I don't think anyone would know since there haven't been any printers sold yet.

I would wait until people get this printer and open it up to see how it exactly works

---

http://www.marinusdebeer.nl/

I would'nt hold your breath what they are attempting would test NASA.

Their problem is not with the printer development, its with the materials, in order to get maximum stiffness out of the CF you have to make sure each strand of the CF is coated properly with the base polymer in this case nylon-its called wetting in the industry. If you don't do this then the CF strands will not stick together when they are printed, in fact the picture shows they are not wetted at all, basically you have a load of loose string inside a nylon case, which is next to useless. Obviously the hype generated by this idea is just that- hype, the technical issues to make a printer actually do what they say would take a huge amount of money and R&D to solve the wetting problem, way beyond kickstarter funding.

---

# 500

i think it would be worth trying to feed the fibre into standard extruder with filament (nylon?) where the temperature and presurre of the melted material would soak the fiber like a resin and push it through nozzle (perhaps bigger diameter)... this shouldn´t be a problem i guess.. perhaps designing some cutting tool ... don´t have an idea how hard/easy is to cut CF/GF... any1 have a GF or CF sample to try this?

Quote
rm2014
I am wondering if there is a cutter of some sort built in to cut the CF and allow transition to the nylon extruder head.

even i am curious about the mechanism he uses to cut a yarn at the end of a layer.

Quote
arnab05
even i am curious about the mechanism he uses to cut a yarn at the end of a layer.

Me too. Depending on the technique, this approach for strengthening prints might be applicable beyond CF reinforcement of nylon.

If it can scale up, it might be a useful way of increasing the strength of printed concrete walls. Possibility even using renewable materials like hemp rope. Vertical rebar could still be inserted to increase the shear strength.

guys what do you know about the chopping mechanism in spray gun used in spray lay up of composites?could that be used?

I saw one run up close last spring. It has a 'dual' extruder and runs filament through one side then fibre through the other off the little spools you can see in the back(the filament spool is mounted on the OUTSIDE on the back).

The slicer software that comes with the printer will lay each per layer(or not). I was also told the support of either material is configurable so you can setup different ratios of material to fibre in different patterns/fills.

CF can be cut with a knife/shear its just rough on the blade. the setup to cut it doesn't need to be fancy, and in this case it's small enough to fit on the gantry... exacto blade on a pivot? dunno... took a peek... didn't take it apart.

Epop nice to hear they are moving on with the project

Next time you see them tell them:


We need to see Stiffness test data on printed v layup peices, the mechanical process is fairly easy but getting reasonable adhesion of base polymer to the cf is very difficult in small printer heads. The residence time required to wet the cf strands is crucial and a way of seperating them as they move through the extruder necessary to efficiently coat them. In large production machines this is done by side feeding the cf into the melt flow through a series of 90 degree bends see us patent 4439387. I have built a head which dose this but its so large it will not fit on a home printer i was getting 50-60% stiffnes v layed up parts, only way i see to increase this would be to increase melt flow and pressure which will increase the size and weight even more, i need to build a printer powerfull enough to carry the print head first.

Edited 1 time(s). Last edit at 09/22/2015 05:45AM by rm2014.

---

# 500