What Are Carbon Composites And How Are They Made?

Composites combine two different materials to generate a component with unique mechanical properties. This article introduces composites more broadly, covering key fiber types and use cases, before focusing on carbon fiber composites, particularly. It breaks down how carbon fiber parts are made and how Holy Technologies’ IFP system delivers recyclable, high-performance carbon components faster. The article ends with a checklist for you to assess if carbon composites are worth considering for your next component.

‍

What Are Carbon Composites?

Before we focus on carbon fiber, it is important to understand what composites are, and the different types that exist. Composites are engineered materials made by combining two or more distinct materials to achieve performance characteristics that are superior to those of the individual materials alone. When brought together, they do not blend; instead, they retain their separate identities within the structure, with each component playing a unique role.

‍

At their core, composites consist of:

• Reinforcement: This is the structure’s main load-bearing element, often in the form of fibers or particles. Reinforcements provide strength and stiffness.
  
• Matrix: This is the material that surrounds the reinforcement. It binds the structure, maintains its shape, and protects it from environmental and mechanical damage.

‍

Together, these two components form a composite with properties, like strength-to-weight ratio or fatigue resistance that are tailored for demanding applications across industries.

‍

Many Types, Many Applications

The diversity of composites begins with their reinforcement fibers. Each fiber type has distinct characteristics, mechanical properties, cost, processing requirements, and sustainability profile, all of which shape where and how the composite is used.

‍

‍

Aramid Fiber

Aramid fibers are organic polymers known for their excellent impact resistance and toughness. While not as stiff as carbon fiber, aramid is far more resistant to abrasion and does not splinter upon failure. It is often used when impact resistance is critical.

‍

Common applications include:

• Defense and security: ballistic protection, body armor
  
• Aerospace: radomes, fairings (where radar transparency matters)
  
• Sporting goods: helmets, protective gear
  
• Industrial: belts, ropes, gaskets

‍

‍

Glass Fiber

Glass fiber reinforced polymer (GFRP) composites offer a good balance of strength, flexibility, and cost-effectiveness. Though heavier than carbon fiber, they are much more affordable and easier to process.

‍

Industries using glass fiber composites include:

• Construction: panels, rebar, cladding
  
• Automotive: non-structural body parts, interiors
  
• Marine: hulls, decks, reinforcements
  
• Wind energy: turbine blades

‍

‍

Natural Fiber

Natural fibers such as flax, hemp, and jute are gaining traction due to their sustainability, low cost, and relatively low weight. While they cannot match the mechanical performance of synthetic fibers, they are sufficient for semi-structural and aesthetic applications.

‍

Used in:

• Automotive: interior panels, dashboards, trunk liners
  
• Consumer goods: furniture, packaging, design objects
  
• Construction: insulation panels, non-load-bearing structures

‍

Carbon Fiber

Carbon fiber is prized for its high strength-to-weight ratio, stiffness, and fatigue resistance. It is commonly paired with a polymer resin (epoxy or thermoplastic) to produce a composite that is both lightweight and mechanically robust.

‍

This makes it ideal for high-performance applications in:

• Aerospace: structural components, fairings, interior panels
  
• Automotive: lightweight body panels, structural parts
  
• Industrial machinery: precision components requiring stiffness and durability
  
• Consumer products: sports equipment, electronics, and performance gear

‍

In the remainder of this article, we will focus specifically on carbon fiber composites. Unless stated otherwise, all further references to “composites” will refer to this class of material.

‍

How Are Carbon Parts Made?

To understand how carbon fiber parts are made, it helps to break the process into five key elements: reinforcement, matrix, fiber deposition, impregnation, curing, and post-processing. Each of these can be configured in different ways, shaping the final part’s performance, cost, production speed, and sustainability.

‍

1. Reinforcement

Fibers that carry load and define mechanical properties. The choice of reinforcement affects how precisely fibers can be placed, how complex the geometry can be, and the ease of material recovery or recycling. Common formats include:

• Chopped fiber: Short strands, used in injection molding, sheet molding compound (SMC) or 3D printing.
• Continuous dry fiber: Long unimpregnated strands, allowing full control over fiber direction and placement.
• Prepreg (pre-impregnated) fiber: Sheets or tapes that come pre-loaded with resin, often used in high-performance industries for consistent quality.

‍

‍

2. Matrix

Surrounds and binds the fibers, transferring loads and protecting the structure. Matrix choice impacts toughness, chemical resistance, and recyclability. Most carbon fiber composites use polymer resins, typically:

• Thermosets like epoxy (commonly used, high strength, irreversible),
• Thermoplastics (recyclable, tougher, reshapable).

‍

3. Fiber deposition

How the reinforcement is shaped into the desired form.

• Manual methods:
  
  • Wet layup: Fibers placed by hand, liquid resin applied manually.
  • Prepreg layup: Pre-impregnated sheets placed by hand, ready for curing.
• Automated methods:‍
  
  • Automated Fiber Placement (AFP): Robots place narrow prepreg tows on complex molds.‍
  • Automated Tape Layup (ATL): Similar to AFP but with wider tapes for simpler shapes.‍
  • Tailored Fiber Placement (TFP): Dry fibers stitched into custom patterns on a carrier.‍
  • Infinite Fiber Placement (IFP): Holy Technologies’ method for placing dry fiber bundles along optimized paths around guiding pins.

‍

For full insight on what each technology can do and which technology is right for your part, consult our production comparison article here.

‍

4. Impregnation

This step introduces the resin to the dry fibers. Impregnation quality affects void content, consistency, and processing time.

• Wet layup: Resin applied manually during placement.
• Vacuum-assisted-resin-infusion (VARI): Vacuum draws resin through a dry stack in a sealed mold.
• RTM: Resin injected into a closed mold containing dry fibers.
• Prepreg: Resin is added during fiber production; ready for layup.

‍

5. Curing

After injecting the resin it can be cured by applying heat and pressure to ensure high quality components

• Autoclave processing: Uses high pressure and heat for aerospace-grade quality.
• Oven curing: No external pressure, common and simple method to induce heat into any component.
• Induction heating: Direct heating of metallic moulds allows fast heating cycling and high energy efficiency.
• Heated press: Hydraulic or electric force is able to apply high pressure closed molds and ensure high throughput rates.

‍

6. Optional: Post-Processing
Final steps to meet part tolerances, performance, or aesthetic requirements. Post-processing affects surface quality, cost, and production speed, and may be minimized in near-net-shape or automated processes. For IFP, post-processing is not needed, because of built-in design features, such as holes and inserts.

• Trimming and cutting: Removal of excess material or flash from molding.
  
• Drilling and machining: Used for inserts, holes, or final dimensional adjustments.
  
• Surface finishing: Painting, coating, or polishing to improve durability or appearance.

‍

The choices made across reinforcement, matrix, deposition, impregnation, curing, and post-processing determine part quality, production speed, and recyclability.

‍

Common Production Trade-Offs

In traditional composite manufacturing, improving one factor, like part quality, often means compromising on cost, speed, or sustainability. Manual layups offer flexibility but are slow and hard to scale. Automated systems improve throughput but are often very expensive. We built Holy Technologies to eliminate these trade-offs. By rethinking every layer, from materials to software to robotics, we created a system that delivers high-performance, scalable, and fully recyclable carbon fiber parts without compromise.

‍

Holy Technologies’ Production Approach

At Holy Technologies, we rebuilt the composite manufacturing stack from the ground up. Our system integrates software, hardware, and material science into one tightly controlled process, delivering high-performance carbon fiber parts with less waste, faster turnaround, and full recyclability.

• Reinforcement: We use continuous dry carbon fibers for precise placement, minimal waste, and full end-of-life recovery.
  
• Matrix: A recyclable epoxy resin provides strong bonding and durability, optimized for closed-mold processes like RTM.
  
• Deposition: Our proprietary IFP system places continuous dry fibers robotically along optimized paths, tailoring mechanical properties like stiffness or flexibility with precision.
  
• Impregnation & curing: RTM allows us to impregnate and cure the part in one step, producing net-shape components directly in the mold.
• ‍No post-processing needed: Design features such as holes, cut-outs, and inserts are integrated directly into the mold and fiber paths, eliminating the need for trimming, machining, or secondary operations.

‍

It all begins in a virtual environment, where we simulate loads and geometries to compute ideal fiber paths. These simulations drive the IFP system directly, placing material only where it matters. The result: stronger, lighter parts with ~97% average fiber property retention after per recovery cycle, and a process that scales from prototype to production. Currently, IFP works best for parts ranging from ~100 mm to ~1500 mm in size. Highly complex double-curved geometries may require segmentation or custom tooling.

‍

For a full deep dive into our IFP technology and workflow, read this article.

‍

‍

‍

‍

How To Get Started With Carbon Composites?

In order to figure out if carbon fiber is a material you should consider for your next component, you can ask yourself the following questions:

1. Do I need a high strength-to-weight ratio?

2. Does my part experience significant mechanical loads or fatigue?
3. Is space or volume limited in my design?
4. Do I have tight performance or dimensional tolerances to meet?
5. Am I optimizing for lifetime performance, not just upfront cost?
6. Would lighter parts help me meet emissions, energy, or speed goals?


‍

For a practical print-out of this checklist, download our our free PDF which you can find on top of this article.

‍

At Holy Technologies we are passionate about helping businesses innovate with carbon fiber and to make innovation as easy and fast as possible. Curious to find out your innovation potential? Book a free part assessment with our tech below.

‍

Appendix: Glossary

Composite: An engineered material made by combining two or more distinct materials to achieve enhanced mechanical properties.

Reinforcement: The load-bearing element in a composite, typically in the form of fibers.

Matrix: The material that surrounds and binds the reinforcement. Maintains shape, transfers loads, and protects against damage.

Carbon Fiber: A high-performance reinforcement material known for its exceptional strength-to-weight ratio, stiffness, and fatigue resistance.

Prepreg: Fiber that has been pre-impregnated with resin. Offers consistent quality and is used in high-performance applications.