Índice
Iberia Compositech operates three autoclaves at its plant in Calatayud (Zaragoza, Spain) for the manufacture of structural composite parts, with a curing capacity of up to 3,000 mm in diameter by 10,000 mm in length, at 15 bar and 300 °C.
That figure, the usable curing envelope, is the first question a programme engineer asks when qualifying a composites supplier. This article sets out the curing capacity actually available, the dimensional limits of each unit, and what autoclave processing means compared with alternative manufacturing routes.
What autoclave curing is, and why aerospace requires it
Autoclave curing subjects a prepreg laminate to a simultaneous cycle of pressure and temperature inside a pressurised vessel. External pressure consolidates the plies and drives out entrapped air, while temperature cures the resin matrix.
The result is a part with a high fibre volume fraction and very low porosity, typically below 2 %. That combination is what delivers the specific mechanical properties required by primary and secondary aerostructures, and the reason autoclave curing remains the reference process across aeronautics, defence and space despite the existence of cheaper alternatives.
Compared with infusion or compression moulding, autoclave curing offers greater repeatability and far tighter control of the thermal cycle. In exchange it requires substantial capital equipment and longer cycle times, which is why installed large-format autoclave capacity remains scarce across Europe.
Autoclave curing capabilities at Iberia Compositech
The Calatayud plant operates three autoclaves in different formats, allowing each part to be matched to the most efficient unit rather than tying up a large autoclave with short runs.
| Unit | Usable dimensions | Max. pressure | Max. temperature |
|---|---|---|---|
| Olmar OF 9563 | Ø 3,000 × 10,000 mm | 15 bar | 300 °C |
| Olmar AT-3000 | Ø 2,700 × 6,000 mm (57,000 L) | 8 bar | 250 °C |
| Maroso AMC | Ø 1,500 × 3,000 mm | 10 bar | 200 °C |
| Olmar (coming soon) | Ø 1,800 × 5,000 mm | — | — |
The Olmar OF 9563 is the largest unit and sets the plant’s dimensional ceiling: it accepts parts up to 10 metres in length, covering large structural elements such as spars, torsion boxes, fuselage sections and large-format radomes.
As part of its capacity expansion plan, Iberia Compositech expects to add a fourth Olmar unit in an intermediate Ø 1,800 × 5,000 mm format, aimed at medium production runs.
What actually fits: reading the dimensional limits
The autoclave’s usable volume is not the real limit on part size. Curing tooling has to be deducted — on large-format parts it can take up a significant share of the available diameter — and clearance must be left for hot air to circulate around the assembly.
As a practical benchmark, the Olmar OF 9563 comfortably handles parts up to roughly 2,500 mm in section and 9,000 mm in length once mounted on tooling. Dimensional validation is nonetheless carried out part by part during industrialisation, including tooling design and thermal cycle simulation.
From prepreg to autoclave: the clean room
Autoclave curing does not begin at the autoclave. The final quality of a structural part is determined during lay-up, which is why Iberia Compositech operates a 1,200 m² clean room dedicated to prepreg lay-up, within an 8,000 m² facility.
The clean room controls temperature, humidity and airborne particulates, and manages full prepreg traceability: freezer life, out-time and accumulated shop life. These parameters are audited in any aerospace supplier qualification, and their records form part of each part’s manufacturing file.
Materials and sectors
The plant’s autoclaves process carbon fibre, glass fibre and aramid prepregs.
Iberia Compositech manufactures composite parts for the aeronautics, defence, space and automotive sectors, and is registered with the Spanish Defence Industry Register (Registro de Industria de Defensa) of the Ministry of Defence.
Certifications
Iberia Compositech holds ISO 9001 and EN 9100 certification, the latter specific to the aerospace and defence sector, covering configuration management, traceability and special process control requirements.
ISO 14001 certification and NADCAP accreditation are both currently in progress, and neither has been obtained as at the date of publication of this article.
Frequently asked questions
What is the maximum part size Iberia Compositech can autoclave cure? The largest autoclave at Iberia Compositech accepts parts up to 3,000 mm in diameter by 10,000 mm in length, at 15 bar and 300 °C. Allowing for tooling, the practical limit is around 2,500 × 9,000 mm.
What is the difference between autoclave curing and infusion? Autoclave curing applies external pressure in addition to temperature, reducing porosity below 2 % and raising fibre volume fraction. Infusion is cheaper and needs no pressure vessel, but delivers lower mechanical properties and reduced repeatability, so it is generally not accepted for primary aerostructures.
What certifications does an autoclave composites manufacturer need for aerospace work? EN 9100 is the reference standard, incorporating ISO 9001 requirements plus aerospace-specific ones. Many programmes additionally require NADCAP accreditation for special processes. In defence, registration with the national defence industry register applies, and certain contracts require AQAP/PECAL certification.
Which materials can be autoclave cured? Carbon fibre, glass fibre and aramid prepregs, with thermoset epoxy or bismaleimide matrices. The unit’s maximum temperature determines which resin systems can be processed: the 300 °C rating of the Olmar OF 9563 allows high-temperature matrices.
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