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MaterialsLOOP vs continuous-fibre 3D printing: what changes
Updated 15 October 2026
Continuous-fibre 3D printers lay fibre in flat layers in the XY plane, and the fibre never leaves its layer. LOOP lays fibre on up to 6 axes, on a tilting table or a rotary mandrel, following the loads in 3D, with thermoset towpreg and compaction and cure in a mould. The former are ideal for prototypes and tooling; LOOP for structural production parts.
By Valerio Di Pompeo, co-founder and CEO of Spherecube
How a continuous-fibre 3D printer works
A continuous-fibre 3D printer builds the part like any extrusion printer: one flat layer after another. In each layer a head deposits continuous fibre, usually embedded in a thermoplastic matrix, along paths that stay in the XY plane. When the layer is finished the bed moves down and the next one starts. It is an accessible, clean process suited to an engineering office, and it brings continuous fibre into parts that would otherwise be plastic only.
The limit is geometric. The fibre never leaves the plane of the layer: loads that run across the layers, or follow a surface curving in space, are carried by the matrix between one layer and the next. The part also consolidates during printing, without compaction in a mould after deposition.
How LOOP works
LOOP is Spherecube's system for automated composite manufacturing and it derives from AFP, not from extrusion printing. It lays a thermoset towpreg, impregnated in-house on LOOM, on up to 6 axes, on a tilting table or a rotary mandrel. The tow is laid perpendicular to the surface and follows the loads in 3D as well: on curves, tapers and closed shapes. It stops only where needed and restarts at exactly the right point, with fibre positioning to ±0.2 mm.
After deposition the part is compacted and cured in a mould: in a press, an autoclave or under vacuum. For 3K UD carbon/epoxy the Spherecube data sheet reports 2800 MPa tensile strength, a fibre volume fraction above 60% and a void content below 2%.
Side-by-side comparison
| Continuous-fibre 3D printing | LOOP | |
|---|---|---|
| Fibre direction | In the XY plane of each layer | Up to 6 axes, in 3D as well |
| Support | Print bed | Tilting table or rotary mandrel |
| Matrix | Usually thermoplastic | Thermoset towpreg from LOOM |
| Consolidation | During printing | Compaction and cure in a mould |
| Curved surfaces and closed shapes | Approximated by layers | Followed by the tow |
| Fibre positioning | Machine-dependent | ±0.2 mm |
| Working volume | Machine-dependent | 400 × 400 × 350 mm |
| Typical use | Prototypes, tooling, functional parts | Structural production parts |
LOOP data from the Spherecube data sheet for 3K UD carbon/epoxy and the LOOP specifications.
When to choose which
Choose a continuous-fibre 3D printer when you need a prototype quickly, a fixture, a jig or a functional part that works mainly in the plane of its layers, and when a thermoplastic matrix without compaction in a mould is good enough for the job.
Choose LOOP when the part is structural and the loads are three-dimensional, when the geometry is curved, tapered or closed, when co-cured metal inserts are needed and when every part must come out the same as the last. In the aerospace and defence bracket case study, moving from 7075 aluminium to carbon with LOOP gave −92% weight, −50% cost and −99% material waste.
The two technologies can also work together: the 3D printed prototype checks shape and fit, LOOP takes the same part into production with fibre oriented along the loads.
Frequently asked questions
Is LOOP a continuous-fibre 3D printer?
No. LOOP is an additive manufacturing system derived from AFP: it lays a thermoset towpreg on up to 6 axes, on a tilting table or a rotary mandrel, and the part is then compacted and cured in a mould. A continuous-fibre 3D printer builds the part from flat layers stacked in the XY plane.
Can a continuous-fibre 3D printed part replace a structural component?
It depends on the loads. If the part works mainly in the plane of its layers, it may be enough. If the loads are three-dimensional, or compaction and a controlled void content are needed, a process that orients fibre in 3D and consolidates the laminate, such as LOOP, is the better choice.
Can I start from a 3D printed prototype and move to LOOP?
Yes. All we need is the 3D model in STL: in LACE it becomes a set of fibre paths and the program for LOOP. With a feasibility study, in 10 working days we tell you whether and how it makes sense to produce the part with LOOP.
Have a part and not sure which process fits? A feasibility study takes 10 working days.
Request a feasibility studyMore comparisons: AFP vs hand lay-up · LOOP vs filament winding · Glossary · Publications