Siraya Tech’s New ASA-CF Core Filament Tackles Carbon Fiber’s Layer Adhesion Problem

Carbon fiber-filled filaments offer improved stiffness and dimensional stability, but research has shown that the fiber reinforcement can also weaken bonding between printed layers. Siraya Tech aims to address this trade-off with its new Fibreheart ASA-CF Core($49.99/kg), which confines the chopped carbon fibers to the core of the filament, which is surrounded by a fiber-free shell made from impact-modified ASA.

The filament contains a high level carbon fiber by weight, 20%, with the reinforced core providing rigidity while the outer shell promotes adhesion between successive layers, according to Siraya Tech.

The idea is to retain the mechanical advantages of carbon fiber without compromising Z-axis strength, traditionally a weak point for FDM-printed parts.

Although Siraya Tech did not invent the fiber core concept, there’s a similar carbon-fiber core ASA filament offered by QidiTech, but does offer it in more variety than the competition. This new ASA Core joins the company’s ABS Core and PPA Core.

According to Siraya Tech’s internal testing, ASA-CF Core achieves a Z-axis tensile strength of 33 MPa. That’s a promising figure for a reinforced filament, especially if you compare it to, say, Polymaker’s Fiberon ASA-CF08 with just 8% fibers that reports a Z-axis tensile strength of 25 MPa. Bambu Lab’s ASA-CF has a reported 30 ± 4 MPa Z-axis tensile strength, but the carbon fiber content is less than half that of Fibreheart ASA-CF Core. Interestingly, most makers of carbon-fiber ASA don’t report Z-axis tensile strength, only, XY-axis tensile strength.

Strength Comparison of Popular ASA Carbon Fiber Filaments