FDM is currently the most well-known and widespread 3D printing technology which melts a plastic spool and a nozzle applies it on a build platform.

CFF is a technology patented by the Markforged company. It allows to strengthen the basic plastic material by layering continuous kevlar, glass or carbon fibres. It creates composite products with extremely high strength.

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Why is FDM/CFF unique?

With a combination of the FDM and CFF techniques, it is possible to make composites suitable for the most demanding applications while keeping the strength of the pieces comparable with aluminium. The products are also significantly lightened at the same time thanks to the internal filling and material density. This technology is a low-cost alternative to CNC machining because the process does not produce waste and requires low operating and technological demands.

Produce extremely resistant and strong parts with perfect precision
  • Combined properties of composite materials
  • Reduced production costs and weight
  • Consistent output quality
  • Strength comparable to aluminium
  • High precision of production

When is FDM/CFF the most suitable?

  • Measuring and welding jigs features
  • Shaped jaws and parts of jigs for CNC machining
  • Production of functional finished parts with high mechanical strength
  • Prototyping of functional parts as a replacement of machining

With composite printers, you produce without compromises and limitations.

Technical parameters

Parameter Value
Avarage lead time Already from 24 hours, depending on the size and number of components and amount of finishing works
Print accuracy In XY direction ± 125 mikrometers
In Z direction ± thickness of a single layer height
Layer thickness 100 micrometers
Minumum wall thickness 0,8 mm
Print volume 320 x 132 x 154 mm
Surface quality Parts after printing have gentle rought surface. Quality highly depends of part orientation in the printer (relative to surface bed) and layer thickness


Onyx – technical thermoplastic. A specifically developed material which can be used only in Markforged printers. It is nylon filled with carbon fibre particles with high strength, excellent heat and chemical resistance and great surface quality. 

Continuous glass fibre – parts strengthened with continuous fibre. Basic and affordable fibre. It is 2.5 times stronger and 8 times stiffer than Onyx. In a combination with Onyx, you can produce stiff and resistant products. 

Continuous HSHT glass fibre – strength at high temperatures. Very strong and heat-resistant glass fibre as strong as aluminium. It is 5 times stronger and 8 times stiffer than Onyx. It is suitable for extremely mechanically- and thermally-taxed parts.

Continuous carbon fibre – strength of aluminium, half its weight. Among all the other fibres, it has the highest strength-to-weight ratio. It is 6 times stronger and 18 times stiffer than Onyx. It can be used as a replacement of machined aluminium parts.

Continuous kevlar fibre – high strength and toughness. With an excellent toughness, it can be used for repeated or intermittent load. Its applications thus include various types of grippers and jigs which are cyclically or intermittently loaded.

Download datasheet

Measured parameter Test (ASTM) Carbon Kevlar® Fiberglass HSHT fiberglass
Tensile Modulus (GPa) D3039 800 610 590 600
Tensile Stress at Yield (MPa) D3039 60 27 21 21
Tensile Strain at Break (%) D3039 1,5 2,7 3,8 3,9
Flexural Strength (MPa) D7901 470 190 210 420
Flexural Modulus (GPa) D7901 51 26 22 21
Flexural Strain at Break (%) D7901 1,2 2,1 1,1 2,2
Compressive Strength (MPa) D6641 320 97 140 192
Compressive Modulus (MPa) D6641 54 28 21 21
Compressive Strain at Break (%) D6641 0,7 1,5 - -
Heat Deflection Temp (°C) D648 B 105 105 105 150
Izod Impact - notched (J/m) D256-10 A 960 2000 2600 3100
Density (g/cm3) - 1,4 1,2 1,5 1,5

1  - Measured by a method similar to ASTM D790. Thermoplastic-only parts do not break before end of Flexural Test.

How does the FDM/CFF technology work?

Markforged printers combine FDM technology with layering of continuous kevlar, glass or carbon fibres (CFF technology).

Basic material, also called a “matrix”, has a high proportional ratio of lengthening. However, on its own, it is not strong and stiff enough. This drawback is compensated by the integrated fibre in certain cross-sections of the model. The distribution and amount of the fibre is very precisely calculated by integral Eiger software with the possibility of manual setting.

This creates a very strong and resistant composite product whose properties can be compared to machined aluminium (when using kevlar and carbon fibres).

The principle of composite materials in 3D printing is explained in the video below: