With the consolidation of the FFF technology, filaments with a high level of additives and fillers have started to be accessible for 3D printing. These fiber-filled materials count on improved mechanical properties and higher thermal resistance, which makes them ideal for engineering projects of all types.
This white paper will help you gain more knowledge on the properties of the different composite materials available in the market nowadays, and their applications in 3D printing.
Fillers have been used in the plastic industry since its beginning: the main purpose of fillers was initially to reduce the amount of costly polymer matrix in a blend, and so increase the economic yield of the manufacturing process.
Depending on the chosen combination of filler and polymer matrix, the consequent filled material can acquire much better properties, compared to the original polymer alone.
The addition of filler is know to impart one or more of the following benefits:
- Reduction of cost
- Improved mechanical properties (e.g. stiffness, hardness, impact resistance)
- Improved thermal resistance and thermal conductivity
- Reduce thermal expansion
- Fire retardancy
A special class of fillers is represented by fibres: contrary to spherical or irregular particles, fibres have a high aspect ratio. Tensile strength and modulus are properties that are normally enhanced by the addition of a fibre filler. The most common fibre fillers are glass fibre (cheap and stiff), carbon fibre (strong and heat resistant), aramid fibre (impact and heat resistant), acrylic (cheap and low density).
Polyamides such as PA are commonly blended with carbon fibres: the two materials are exceptionally compatible, and in the right proportion result in a very stiff and sturdy blend, with a strength comparable to that of a weak aluminium alloy, but for half the weight. Carbon fibre-filled polyamides largely find applications in the automotive industry, for parts in contact with oils and subject to loads in aggressive environment such as the engine bay of a car.
To better show the effect of the addition of carbon fibres to a polyamide matrix, we compared the properties of our two filaments PA (polyamide) and PAHT-CF15 (polyamide, 15% carbon fibre-filled). PA is characterised by being a flexible and durable material, ideal for moving parts, when sudden hits or falls are expected. The addition of 15% carbon fibre completely transforms the polyamide blend into a very stiff material, capable of withstanding heavy loads without flexing, even at high temperature.
An important advantage of the addition of fibres to thermoplastic is a generally improved thermal resistance, which is normally translated into better dimensional stability in hot environments, such as car engine bays, electric panels and in proximity of moving parts. PAHT-CF15 withstands temperatures 42% higher than what tolerated by unfilled PA (Figure 8). This makes PAHT-CF15 an ideal material for structural and supports element, designed to work in hot environments.
The addition of fibres in 3D printing filaments also affects the printability properties of the material. For example, in the molten state, the presence of rigid, solid particles greatly increases the melt viscosity of the blend, thus requiring higher printing temperatures to ensure an optimal flow.
Another aspect to take into consideration is the abrasive effect of solid particles/fibres. The use of carbon and (especially) glass fibres can result in a considerable wear of the classical brass nozzle over a relatively short period of time. For this reason, when working with fibre-filled materials, to ensure consistent printing performances a special hardened nozzle such as BCN3D Hotend X is highly recommended.
Get to know the BCN3D fiber-filled filaments
Our range of BCN3D Filaments include carbon and glass fibre-filled materials for the most demanding and technical applications. These filaments feature the mechanical benefits provided by fibre reinforcement, while maintaining a consistently good printability and surface finish.
Our range includes PAHT-CF15 (polyamide, 15% carbon fibre-reinforced) which we have extensively discussed and PP-GF30 (polypropylene, 30% glass fibre-reinforced).
PAHT-CF15 combines high temperature and chemical resistance with extreme mechanical properties. It allows to print parts able to withstand high temperatures (150 ºC for a prolonged period, peak temperatures of 180 ºC). In comparison with standard PA, the addition of 15% carbon fiber makes the final composite material stronger and stiffer thus introducing new possibilities of application for FFF 3D printing.
PP-GF30 is a high-solid composite filament, filled with glass fibre for chemically resistant, lightweight and dimensionally stable parts. It is amongst the most used filled materials in the automotive industry, characterised by a long service life and able to resist to all weather conditions.
Would you like to know more about 3D printing? Check out the following white papers:
- Anatomy of Sigma & Sigmax R19 extrusion system: Partnering with e3D™ & Bondtech™ manufacturers
- Introduction to FFF technology and its most important parameters
- Introduction to Fused Filament Fabrication (FFF) 3D printing technology
- Guide on how to choose a professional desktop 3D printer – White Paper
- Introduction to the Plastic Manufacturing Industry – White Paper
Ready to save time and cut costs with a BCN3D printer? Request a customized quotation for a BCN3D Printer.