Make Forged Carbon Fibre Parts Using Compression Moulding

hi paul here from easy composites and today i'm going to be revealing the secrets of the forged carbon fiber process and show you just how easy it is to make genuine lightweight high-performance forge parts like these one remarkable thing about this process is that it doesn't require really any specialist tools or equipment i'll just be using the materials from our development kit alongside some basic hand tools in the video i'm going to go through every step in the process starting out by looking at suitable mold design and construction we'll be looking at resin cast molds and directly 3d printed ones we'll then go on to apply a release agent and then load these molds with the fiber and resin before compression molding or forging them into these finished components so what is forged carbon fiber well forged carbon fiber is the term that's used to describe a randomly oriented short strand carbon that's been combined with a resin matrix and compression molded in a multi-part mold there are two fundamental ways you can go about doing this one is to take a chopped uni-directional prepreg load this into a mold and then cure it under pressure and heat or like we're doing today take a dry chopped toe combine this with an ambient curing epoxy and then cure this under pressure only without the need for heat what are the advantages of this process over a traditional composite molding method well this primarily comes down to the geometries that it allows you to produce as you've got a molded face on all sides it allows you to accurately control wall thickness and create features that you wouldn't normally be able to do it also lets you create solid structures these would normally be the reserve of a machined or a forged metal part or indeed an injection molding now being carbon fiber it is incredibly lightweight stiff and strong and will compare to or even outperform metals in many areas so let's take a look at some of the things that you'll need to consider when you're designing compression mold tools the first tool that we're going to look at is this resin cast tool now this is one that we've made in a previous video so if you do want to see how this was made in step-by-step detail do go and check that out but to summarize we've cast solid blocks of resin onto either side of a pre-existing injection molding to create this match tool it's very very strong and durable and should last for many many releases but for very high volume production it'd be most common to see tooling like this done in solid billet aluminium needless to say this would be incredibly strong and durable but along with that it would also be significantly more expensive to produce so for short batch runs or prototyping this is a really cost effective alternative and it also comes with the advantage that you don't need any specialist tools or equipment the other type of mold that we're going to be using in this video is one that's been directly 3d printed so this has come straight off our ultimaker printer and it's printed in pet g now if you have seen any of our other videos where we feature 3d printing you'll probably already know that petg is my favorite print material for composites projects the reasons for that are that it offers really good release from most resin systems it's also relatively strong stable and easy to print now i have used quite a high infill level of 75 on these and that's to make them strong enough to withstand the clamping pressure used in the compression molding process when you're designing moulds for compression molding there's really one major difference between this and a conventional mold tool and that's how the mold parts close together so if we take a look at the two-piece resin cast tool which is probably the easiest to understand we can see this so we've got the female tool and the male tool and this leaves a cavity where the part is formed but around the perimeter of both of these is a short near parallel section and this acts almost like a piston inside a cylinder and this needs to be long enough to allow us to compress that material because when we first load it into the mold it's going to be quite bulky because it's not being compressed so when the sort of piston meets the cylinder for the first point that's when the compression can start then as we close those molds parts together the fiber will move around in the mold and the resin will escape from the gap in between these two mold parts but the fiber won't because these are very very closely fitting now in the case of a two-piece mold you do need to have a slight draft on these of around two or three degrees if these were completely parallel you would have difficulty separating the two mold halves but if they were too shallow it would leave a gap during closure that some fiber might escape through and could cause problems with your closure but in the case of a three-piece mould like the 3d printed one that we've got here that male tool can be parallel or close to parallel because we've got this third part of the mould that can first be broken away and then we wouldn't have any draft angle release problems when we remove that male tool so this three piece mold will first be clamped together in the two lower halves so we've just got some bolt holes in the bottom there that can clamp those together this will then be loaded in with the reinforcement material and when we then clamp in the sort of male piston tool into that that will slide down inside and it will compress the material into the mold and as i say any excess resin will escape through the parting lines in the tool another feature that's really good to add on to any of your tooling are release features so in the case of this 3d printed part we've put a chamfer all the way around the side of one of these tools and that will give us just an area where we can drive a wedge and that will help us in the separation of the mould tools in the case of the resin cast tool we included the same sort of ramp features cast into the resin and again that just gives us a location for wedges to be driven in the print can now be quickly cleaned up with a knife and have all of the supports removed when you're doing a clean up take a look over any of the sharp corners that you've got because the 3d printing process has a tendency to bulge in these areas so where we've got a flat face here it's just bulging slightly as it goes over that corner and so if you want your molds to close up really tightly it's a good idea to either sand these back or shave them back using a blade although not absolutely necessary i do find it can be helpful to just lightly sand with fine sandpaper some of the layer lines out of the areas in the closure and this will just make the release later on that bit easier so that's the moulds covered now let's get started forging some carbon for this project i'm going to be using the forged carbon fiber development kit although we do supply all of these exact same materials in bulk quantities to big industry i do hope this development kit will encourage a lot of you to give this highly effective process a go so from this point forward in the video all of the materials that you'll see me using are from that kit and you do get quite a lot of material so you've got enough chopped toe and resin to make over a kilo's worth of these components and to put that into some perspective that would be about 10 of these flywheel covers or 50 of the levers that we're going to make the first stage in the process is to apply the release agent the release agent that we're using today is the rw4 high build release wax the rw4 is a really easy release agent to apply it's simply done by spraying a thin film over the surface of the mold allowing this to dry and then repeating typically three times or until you've got the build thickness that you want in the case of multi-part molds you do need to ensure that you leave these molds separate and spray over all of the surfaces as this will ensure that the parting lines will also separate easily once they've got resin driven between them now typically i wouldn't use the rw4 for a composites application and that's because it doesn't provide the best surface finish and it's also only suitable for ambient temperature cures like we're doing today but because it builds a thick wax film over the surface of the mold it does do a particularly good job of separating rigid parts from rigid molds making it perfect for this process so with the wax all dried out we can now look at bolting these molds together now where the bolts run through the mold resin will squeeze in this gap and could lock the bolts in so i've treated these using some filleting wax and just filled in all of the thread and that will make the extraction much easier later on looking back now at the flywheel cover mold there are some features on here that i didn't mention earlier and that's ejection points for the part so you can see them sealed in here with the filleting wax and what these are are holes drilled all the way through the mold that allow me to insert some dowel pins in there and then once the part's been made we can drive those dowel pins out from the back and that will eject the component making the release much easier now even if you don't have obvious locations to put these such as bolt hole locations it can be worth doing this especially on two-part molds so if we look at the mold that we've got here for a paddle shifter again we've got these three holes and they'll be filled in with filleting wax and then once the parts made that just gives us a location that we can easily drive out or eject the component with the molds ready we can now look at the carbon fiber itself so we're using the ct-12 choppto carbon and when you're making forged parts it's absolutely essential that you get the right fiber loading in your part if you have too much fiber in your moulds you might not be able to close them properly and if you have too little it won't fully consolidate into all the features and contours to calculate the correct amount of carbon you need to first calculate the volume of the part or the cavity in your mold if you've worked from cad that's really straightforward just right click look at properties and it will tell you how many cubic centimeters or cc's you've got in the part if you've taken your mould from an existing component probably the easiest way to work out its volume is to weigh the component and then work out the volume of it from the density of the material that it's made from you could probably also use a water displacement method however you've worked out the volume of your part you can then go on and calculate the weight of the finished carbon fiber piece and the way that you do this is just take the density of carbon fiber which is 1.4 and multiply it by the volume of your part so if you had a part that was 100 cc's it would weigh 140 grams so in the case of this flywheel cover i've worked out that the finished part is going to weigh 100 grams and from there i can easily calculate the fiber that i'll need to load into it we're aiming for an optimal ratio of 60 fiber to 40 resin so 60 of 100 is 60 so 60 grams of fiber will need to be loaded into this once you know the amount of fiber that you're going to need this should then be weighed out into a separate container so when you're using it you'll know that once you've exhausted that you've got the right amount of material in the mold now that we've got the correct amount of fiber weighed out we can go on and mix the resin now you do need an excess of resin in this process this makes laminating easier and it also allows it to sort of flow around into all of the cavities during consolidation the easiest way i've found to calculate an appropriate amount of resin is to take whatever weight you have in fiber and increase this by 25 for the lever i have 14 grams of fiber so i will need 17 and a half grams of resin the resin that we're using is the in2 infusion epoxy this is a high performance resin system and is particularly well suited to this process due to its low viscosity it offers rapid wet out of the fibre along with great flow in the mold cavity this is mixed as you would any epoxy by accurately weighing out the two parts and then thoroughly mixing ensuring that the sides and bottom of the container are properly scraped and mixed in the first thing you need to do is put a thin coat of resin all over the surface of your mold and this will do two things the first is it will hold the fiber in place it will tack the fiber down the other thing is it will ensure that the surface of the part has got good resin saturation with the resin coat down we can now start loading the fiber when you do this you need to just load a small amount at a time and stipple it to soak the resin through this will ensure that you don't get any dry spots in the core of your part for this process i've found that it's most practical to load the fiber and resin into the mold in a similar way to hand laminating and not to attempt to try and pre-combine the resin and fibre although this process is a bit of an inexact science and is generally very forgiving you should still try to load the fiber as evenly as possible you will find that it might seem like you have far too much fibre than will fit into the mold that's normal after all when this material gets compressed later on it needs to be under pressure for the process to work properly depending on the size and shape of your part you might find that you need to mix up a little bit more resin than the amount calculated in order to fully wet out the fiber it's okay if that is the case it will just mean that more will need to be squeezed out during compression sticks rods and other blunt tools can be helpful in order to get the material properly consolidated into the mold when loaded the fiber will feel quite firm and compacted with the fibre and resin loaded into the mould you can see just how important it is to have the extension on the mold because this material is yet to be consolidated it's taking a lot of volume and it's nearly coming out of the top of this mold if that feature was any shallower we'd really struggle to close those mould halves together without trapping the fibre when you close the mold there's likely to be a few odd fibers that get caught in the parting line if it's only a very small amount this shouldn't cause any major problems here i'm just using a portable vise to compress this small mold you will notice that i've used some metal spreader plates on either side of the mold to even out the clamping pressure but for something like this this could easily be made from wood i've also put a piece of film under the part to catch any drips of resin once positioned in the vise it's very important to exercise patience and clamp the mold progressively over a period of about five to ten minutes if you apply the clamping pressure too quickly the excess resin will not have time to flow out of the mold and the resulting pressure from hydraulic lock could easily damage a mold particularly if it's the more fragile 3d printed mould so it's simply a case of returning every minute or two and compressing a little further once the mould is bottomed out you'll be left with the correct geometry and optimal 60 to 40 fiber to resin ratio now moving on to the flywheel cover mold this is going to be done in much the same way as we did with the lever but because this is a thin wall part we do have to pay a bit more attention to the way that we're loading in the fiber so it needs to be reasonably evenly distributed and then just additional material in any of the thicker sections now this process is fairly forgiving in that the fibers will move around during the mold closure but the closer you can get it in the first place the better so we're going to mix the resin for this in just the same way as we did for the lever you will find that a slow stippling action with the brush will effectively wet out the fiber without disturbing it too much one thing that's worth mentioning on a more general note this forge process is generally not appropriate for large panels due to the surface area a large flat panel would require huge clamping pressure in order to consolidate the part properly which in the most part wouldn't be practical if i had to put a number on it i would say that around quarter of a square meter would be about the limit for conventional clamping or pressing methods panels larger than this would definitely fall into the domain of conventional vacuum bag composite processes like resin infusion or prepreg which of course we've previously covered many times whilst i have loaded most of the material into the female side of the mold tool there is one very thick section on this part where i'm going to laminate some of the material onto the male side of the tool because it would otherwise be quite difficult to get this very square block-like shape pre-loaded into just that tool alone so what i've done here is just filled this area in to chamfer it out and then in the female side of the mold i'll have a mirror of that and i'll just chamfer that area and it saves me trying to get to 90 degrees in either case on open thin section components like this don't be afraid to get in there with your hands it can be quite useful to press the fibers into the detailed areas and it gives a good feel for how evenly the material is loaded i'm clamping this mould with conventional g-clamps now i do have a heated pneumatic plan press which i certainly could have used for this but i'm using these clamps to demonstrate that the same excellent results can easily be achieved using only basic tools just like with the previous part the moulds are slowly and evenly clamped until they bottom out this will take around 10 minutes allowing time for the resin to escape i will say that without the low viscosity and excellent flow characteristics of the in2 resin you would likely have difficulty with hydraulically locking the mold and may not be able to properly close them so we've left these to fully cure for 24 hours at room temperature so we can remove the clamps and de-mold them although the moulds almost immediately separate from the part in order to prevent damage to your tooling you need to slowly work from all sides to ensure that the molds remain close to parallel during separation the component will nearly always remain in the female side of the tool but as we have these ejection dowels a few light taps will easily extract it these areas you can see here that whiting that's just from the release wax and actually to give it a quick buff over you can straight away see that the molding underneath is is pretty good we can now look at separating the 3d printed mold it is worth bearing in mind that these are much more fragile than a resin cast mold so you do have to be a bit more careful i'm going to split this on the bottom part of the mold first because my 3d print orientation makes it stronger in that plane the bolts easily removed due to the coating and filleting wax that we have applied to them then in this case just a light blow from a mallet is all that's required to separate them no doubt helped greatly by the rw4 spray wax so here we have the part straight from the moulds you can see the molding has been very successful and we're just left with a few flashlights to clean up and some post machining to do in the case of the moulds these would now be ready to reuse in order to do that you would just clean them down with some mold cleaner reapply the release agent now the resin cast molds i would expect if properly treated these would be able to produce tens if not hundreds of components but the 3d printed ones being that bit more fragile it's only really best suited to small batch runs or almost treating them sacrificially in one-off prototyping first thing we're going to do is clean off the flash line that we've got here now that's really easily done it's just a case of either cutting it back with a knife or sanding it down with a block and then just dressing it in with some wet and dry paper we're going to clean off any of the residue that's been left by the release agent there is a thin film of sort of wax on here and that's easily wiped off just using a cloth and some mold cleaner then we'll go on and do any of the post machining so we'll drill the holes and counterballs that we need in these components leaving us with our mechanically serviceable components with the parts cleaned up these are now ready to fit and use but if you did want to take it one step further and really enhance that forged look like we've done here you could go on and apply a clear coat now clear coating carbon fiber does come with its difficulties and so it is something that we'll cover in a future video but to summarize i've keep the surface down with a 400 grit wet and dry before applying several coats of phantom clear which is a paint system specifically designed for carbon fiber before giving that a final flat out and a polish into the final finish that you see here now another option that you would have would be to brush apply an xcr coating resin and flat that out and polish it and that will give you that same gloss look but i actually quite like the raw finish that's come straight from the mold and of course for the purists out there this would be the lightest option with no finish at all now another thing that i'm sure many of you have been thinking throughout this video is just how strong are forged carbon fiber parts well i can tell you that these are incredibly lightweight and incredibly strong but that's hardly a scientific explanation so in the next video we're going to tackle that subject specifically and we're going to be mechanically testing forged carbon fiber against aluminium and also mark forge 3d printed carbon fiber so that's definitely going to be one to check out i do hope that this video has got you thinking of ways that you might use this process in one of your projects and i would love to hear your ideas in the comments section if you do want to give it a go remember we've made it really easy with the forged carbon fiber development kit available from the easy composites website as ever a huge thank you to all of our customers and subscribers for your support and we'll see you next time of course all of the equipment and materials that you've seen used in this video can be ordered online from the easy composites website if you're based in the eu you can now order directly from our netherlands warehouse on easycomposites.eu and for the uk and the rest of the world please visit easycomposites.co.uk

Channel: Easy Composites Ltd

Views: 2,004,047

Keywords: forged, carbon, fiber, fibre, mould, mold, compression, 3d printer, ultimaker

Id: 25PmqM24HEk

Length: 21min 44sec (1304 seconds)

Published: Thu Dec 09 2021

Reddit Comments

[u/asssnorkler]

Bushmaster made carbon AR receivers back in the day from what I’d assume is a similar process

[u/LabronPaul]

ha im not the only one that got recommended this video. they seem like a fantastic company btw

[u/LostPrimer]

Cool process, but all of the work shifts to the mold design, which if you're not an expert at, you just end up frustrated.

Ask me how I know... (fuggen HDPE...)

[u/Caligula-6]

Try it and let us know how it turns out

[u/contrabardus]

EDIT: Something is fucky with Reddit tonight.

I clicked on a different post from a completely different sub on my front page to comment on, and somehow it ended up here.

I am sure, because I read some other comments before adding mine.

I didn't have this thread, or even this sub, open in a different tab or anything like that.

[u/RootTootPrintNShoot]

Firebolt.