Composite Layups
Last updated
Last updated
Composite Layups are a great way to make extremely strong yet lightweight parts. The basic concept is binding high tensile strength woven fibers with high compressive strength epoxy resins to form extremely stiff, lightweight, and strong parts. Learning composite layups give you a lot of unexplored capabilities compared to all the other fabrications methods discussed previously. Composite projects are complicated (more or less a combination of craftsmanship, art, and science) but with sufficient research and a good understanding of the process, it should not be too hard for more experienced makers to get into.
Composites shine where your mass budget is very low, yet you need high strength parts. In layman's term, it's great for projects where you want the part to be light but strong. This is why composites are so heavily used in aerospace applications. Although composite material itself is often cheaper than many other materials, the manufacturing process is very time and labor consuming. Nearly all composite structures ranging from your small model rocket parts to full sized aircraft airframes requires intensive human labor (Minus some modern automation exceptions). This means the yielding part is generally very costly to manufacture.
Composites are also limited in application by temperature and durability. Although its strength may frequently exceed metal, it can neither be used near very high temperature components such as near engines (Minus exceptions where very advanced composites are produced, but this isn't available to you unless you work at Skunk Works), nor have the same level of durability as metal. Often in advertisement you will see the cliché statements such as “10 times stronger than steel” for composite parts. Although technically true, it practically is not a really valid statement. Composite and metals are totally different materials with totally different properties. Composites can only substitute metal parts when loading, temperature, and application are all carefully considered and applied.
The final factor we will mention is the direction of applied forces on the part. Obviously this applies to any mechanical component designed, but even more so for composites. The principles of composites rely on the tensile strength of the fibers with the compressive strength of the epoxy resin. Because fibers are regularly joined in the form of woven fibers, composite structures are incredibly strong when the fibers are running in the direction of the applied load, but incredibly weak when running perpendicular to the applied load (Think of it like 3D printer layer lines). Parts typically need to be designed with this in mind.
Deciding whether to utilize composites in your project is an equation of factoring in all the variables mentioned, along with manufacturing time and infrastructure. Objectively carbon fiber is actually relatively cheap, but the tooling infrastructure, time, skills, and complicated design required with larger scale composite parts is where the cost starts to add up exponentially. This is why often times in the enterprise space, composites are exclusively used only when the mass savings of composites is overall beneficial enough to justify the long expensive process (Or for the sake of making something luxurious and expensive just because)
Ensure you use proper PPE and responsibly operate in manageable environments! Composites can cause cancer and respiratory illness if handled improperly!
Recent studies have suggested that dust particles from Carbon Fiber and other composites can cause very similar effects as Asbestos. In short, you really do not want to breathe any of the fibers or dust in, they can lead to serious respiratory issues (And lung cancer). Not only are loose fibers and composite dust of concern, but epoxy fumes can also cause lung irritation and brain damage. Always wear a respirator when working with composites and do it in a well-ventilated area (Preferably outdoors where the dust particulates can be diluted into the environment naturally)
Composite fibers and dust can irritate the skin. Although less serious than lung damage, it is extremely irritating with the effect lasting for very long times (We had incidents where we had itchy skin for over a week, it's not fun, trust us!). Always wear disposable gloves when handling composites, and wear a full-body Tyvek coveralls during layup jobs!
Easy Composites is well known for their excellent composite layup videos! What's really awesome is how they cover techniques utilized in enterprise settings down to more hobbyist scale projects. If you're interested in getting into composites or would like to simply learn the basics, we highly recommend you to check out the playlist below.
The CLR is our universal documentation sheet to keep track of all the parameters of your composite layup. It allows your job to be recorded to be replicated in the future, or troubleshoot issues that may arise.
