FAQ on the evolution of AFP

LOOP is an additive manufacturing system for continuous-fibre composites, developed and patented by Spherecube, an Italian company. It lays a pre-impregnated continuous tow (carbon, glass, quartz, aramid, flax or hemp) on up to six axes, orients it in any direction and steers it through curves at constant width. It is the natural evolution of AFP (automated fibre placement) and brings automated composite manufacturing to small and medium structural parts with complex geometry.

Both. The principle is that of AFP: a machine lays continuous fibre along a programmed path. Traditional AFP cells, though, are built for large aerostructures. LOOP is compact, reaches up to 6 axes on small and medium parts, steers the tow at constant width and works on a table or on a rotating mandrel. That is why we see it as both the evolution of AFP and an additive manufacturing system.

No. It is an additive manufacturing system, but it is not 3D printing in the everyday sense. It does not extrude plastic layer by layer like a desktop 3D printer. LOOP places continuous structural fibre, pre-impregnated with thermoset resin, along the load paths on moulds, tools or mandrels. The part is then cured under pressure. What comes out is a structural composite part comparable to an industrial laminate, not a printed prototype.

LOOP ships with 4 axes and can be upgraded to 6, in two configurations: tilting table or rotary mandrel. Either way it has three translations (X, Y, Z) and three rotations and the tow is always laid normal to the surface, even where the shape curves, narrows or closes.

Only when it has to. Fibre carries load as long as it is continuous, so in LOOP it stays continuous. LOOP stops it and restarts it only where the part calls for it: a hole, a change in geometry, a clearance constraint. Every path starts and ends exactly where it should and there are no ply offcuts to throw away. With chopped fibre, by contrast, every fibre end interrupts the load path.

Yes. With the rotary mandrel, LOOP places hoop (90°), axial (0°) and any ±θ fibre on the same part, with local reinforcements and terminations where they are needed. Compared with filament winding, fibre orientation is more precise and 0° fibres reach even tapered ends, cones, ogives, nozzles, flanges and diameter transitions.

No, curing happens outside the machine. LOOP lays the pre-impregnated fibre, then the part goes into a press, an autoclave or an oven under pressure, depending on the resin system and the quality required. LOOM has already fixed the fibre-to-resin ratio, so curing always starts from a consistent laminate. In a press, with epoxy resin, the cure is fast.

LOOP positions the fibre within ±0.2 mm and finished parts reach geometric tolerances down to ±0.2 mm directly from the process. When a drawing requires tighter values, Spherecube finishes the part with CNC machining.

LOOP 00 has a working volume of 400 × 400 × 350 mm. That covers small and medium structural parts with complex geometry: brackets, housings, arms, shells, springs, sleeves and axisymmetric parts.

LACE is Spherecube's proprietary CAD/CAM software for LOOP. It takes a 3D model, works out fibre paths that follow the loads and writes the multi-axis program LOOP runs: head orientation, fibre stop and restart points, deposition speeds.

LACE imports models in STL and 3MF formats. The part is positioned on the mould, tool or mandrel, the material is selected and LACE computes the paths and the machine program.

Yes. LACE keeps several versions of the same part side by side and compares them by weight, material and production time. A timeline replays the deposition step by step before the machine moves, so you choose on screen, not through trials on the shop floor.

You decide, layer by layer. Fibre can run at 0°, 90°, ±θ or along curved paths and the inside of the part can be filled continuously, as a grid or as an isogrid with adjustable ribs. That puts stiffness and strength where the part is loaded. Generative design and topology optimisation are in development, in a closed-loop cloud software that will also monitor the process during deposition.

LACE runs on Windows, Mac and Linux and connects through cloud or NAS, so projects and programs are shared between engineering and production.

LOOM is the machine we use to impregnate continuous fibre. It meters resin at a controlled fibre-to-resin ratio and produces the towpreg that LOOP deposits. The material reaches LOOP ready to use, with the same amount of resin along every length of tow.

Because the fibre-to-resin ratio is what sets the stiffness, strength and porosity of the part. With LOOM we fix it before deposition and it stays the same along every metre of tow. No resin applied by hand, less variability, fewer voids. With 3K UD carbon and structural epoxy we reach over 60% fibre by volume and under 2% voids.

Continuous carbon, glass, quartz, aramid, flax and hemp fibres, with thermoset resins: structural epoxies, bio-based epoxies and high glass-transition systems, including flame-retardant ones. The condition is that the resin fits the viscosity window of the process. Unidirectional tape with structural thermoplastic matrices is in development.

Yes. We start from your specification and prepare a custom fibre–resin combination with LOOM, provided the resin fits the viscosity window of the process. We qualify the material on coupons before moving to the part.

Yes. LOOM meters resin onto the fibre instead of spreading it by hand, so fewer solvents and less waste. LOOP then places fibre only where it is needed. Together, according to a life-cycle assessment published in a peer-reviewed journal, the Spherecube process cuts CO₂ emissions by 80% compared with traditional manufacturing. Source: Procedia CIRP, 2024 · DOI 10.1016/j.procir.2024.01.143

We work with continuous carbon, glass, quartz, aramid, flax and hemp fibres, which we impregnate ourselves with LOOM. The resins are thermosets: structural epoxies, bio-based epoxies and high-temperature systems, including flame-retardant ones. Unidirectional fibres with structural thermoplastic matrices are in development. The material depends on what the part needs: stiffness and strength, electromagnetic transparency, service temperature or environmental impact.

With 3K unidirectional continuous carbon and structural epoxy, Spherecube coupons reach 2800 MPa tensile strength, 151 GPa modulus, 1100 MPa flexural strength, 90 MPa ILSS and a Tg of 130 °C, with over 60% fibre by volume and under 2% voids verified by electron microscopy. These are the values in the technical data sheet (TDS) for this material: other fibre–resin combinations have different values.

QZ-400 FR is our unidirectional continuous quartz fibre material with a very-high-Tg flame-retardant resin. Quartz is transparent to electromagnetic waves and has a low dielectric constant, which is why it is used for radomes, antenna covers and sensor windows. The resin has a Tg above 400 °C after post-cure, is rated UL94 V-0, complies with FAR 25.853 and is low-outgassing to ASTM E595. The material suits aerospace, space and defence parts exposed to high temperatures. Mechanical tests on Spherecube UD laminates are in progress.

Yes. LOOP deposits fibre on a mould, a 3D tool or a rotating mandrel and the part is cured under pressure. What disappears is manual lamination: the fibre is placed by the machine along the load paths, with a repeatable program.

Often, yes, if the part is loaded in known directions. On one of our aerospace projects, a metal structural component redesigned in continuous carbon/epoxy and made with LOOP came out 93% lighter and 50% cheaper to produce, with the required performance maintained. A feasibility study tells you whether your part is a good candidate.

With hand lay-up everything depends on the operator: resin content, compaction and fibre angle change from part to part. At Spherecube, LOOM fixes the fibre-to-resin ratio and the LACE program fixes the fibre path, so LOOP lays every part the same way. On an aerospace component the full cycle dropped from 125 hours to 51; case studies report up to 90% fewer defects, 80% less scrap and 75% less process time.

Filament winding lays a continuous helix under tension on a rotating mandrel: it is excellent for tubes and vessels, but it cannot place 0° fibres, cannot interrupt the fibre and struggles on tapered or closed ends. LOOP uses the same kind of mandrel but combines 0°, 90° and any ±θ angle, interrupts the fibre where the part requires it and adds local reinforcements, with more precise orientation.

Most continuous-fibre 3D printers embed the fibre in a thermoplastic filament and build flat layers, which limits fibre content and leaves voids. LOOP places pre-impregnated continuous fibre with thermoset resin, at a fixed fibre-to-resin ratio, on up to six axes and on curved surfaces. The part is then cured under pressure. The target is structural, production-grade parts.

Yes, automated manufacturing at high rate is the goal. The process is a program, the fibre-to-resin ratio is fixed and the machine repeats the same paths part after part. You start from a first validated part, move to a production cell and then to lines with several machines.

Send us a drawing or a 3D model through the contact page. In 10 working days the Spherecube team delivers a feasibility study: fibre layout, expected weight and a path to production. Then we redesign the part in LACE, validate a prototype and industrialise it up to high-rate production.

For R&D teams there is an early-access release of LOOP: an open machine, with process parameters, deposition paths and materials all accessible. In the long term the offer is the platform in-house: LOOP, LACE and LOOM materials. Contact the Spherecube team for availability and conditions.

Yes. The Spherecube additive manufacturing system is protected by a patent granted in Italy, with extension to Europe and the United States. The process LOOM uses to prepare the material is also patented.

Spherecube's continuous fibre is used where lightness, stiffness and repeatability matter: aerospace, space, defence, drones and UAVs, motorsport, automotive and e-mobility, robotics and automation, industrial and packaging machinery, energy, marine, rail, biomedical and orthopaedics and sport.

Spherecube is based in the Marche region, Italy and works with customers across Europe. The team also brings LOOP to trade fairs, contests, exhibitions and workshops with live demonstrations.

Yes. We bring LOOP, LACE and LOOM to trade fairs, innovation contests and technical events and we run workshops for engineering teams on designing with continuous fibre. Write to info@spherecube.eu or use the contact form.