OOA – out of autoclave
OOA (out-of-autoclave) is a group of methods that give near-autoclave laminate quality without an autoclave. It includes prepregs cured only under a vacuum bag in an oven (VBO), prepreg compression moulding (PCM), SQRTM and moulding with an internal pressure bladder.
Key parameters
| Typical volume | from a prototype to a few thousand pcs/year |
| Pressure | VBO: approx. 1 bar (vacuum); press and SQRTM: higher |
| Porosity | typically approx. 1–2% with a good process |
| Part size | no autoclave chamber limit (VBO) |
| Investment | an oven and presses instead of an autoclave |
| At our plant | OOA oven, 160 t and 40 t hydraulic presses |
Typical, indicative values – they depend on the geometry, material and requirements.
What you can order from us
- VBO prepreg structures without the size limit of an autoclave
- Pressed prepreg parts (PCM, SQRTM)
- Prototypes and small series of prepreg structures
| Materials | VBO prepregs, compression moulding prepregs |
| Typical volumes | from a prototype to a few thousand pcs/year |
| At our plant | OOA oven, 160 t and 40 t presses |
| For a quote send | a 3D model or drawing – or a description and sketch, the requirements and annual quantity |
The OOA methods we use
| Method | How it works | Advantage |
|---|---|---|
| VBO prepreg | Special prepreg with degassing channels, cured under a bag in an oven | Large parts without an autoclave, low tooling cost |
| PCM | Prepreg pressed in a hot mould | Cycle of minutes, two finished surfaces |
| SQRTM | Prepreg in a closed mould + resin injection for hydrostatic pressure | Autoclave quality, porosity below 2% |
| RAT and prepreg – Reverse Autoclave Technology | Oven chamber under vacuum, infrared heating, pressure from a pressurised bag or bladder | More pressure than VBO without pressurising a whole chamber – more about RAT |
| Bladder-assisted moulding (BACM) | Pressure from inside the part through a flexible bladder | Closed parts and profiles; example: the Maserati MC20 roof with 50% lower energy use than in an autoclave |
Polish research confirms that OOA makes sense for smaller aerospace plants: a Warsaw University of Technology team made an aileron demonstrator from prepreg cured only under a vacuum bag, on low-cost polyurethane foam moulds.
When to choose it
- The part is too large for the available autoclave
- You want to cut investment and energy costs at near-autoclave quality
- A medium series where a press gives a shorter cycle than an autoclave
- A prototype or small series of an aerospace structure in VBO prepreg
When another process is better
- Certified aerospace quality on an existing autoclave standard is required
- A very large series of complex shapes – forged carbon or compression moulding
Questions and answers
Is OOA as good as an autoclave?
New generations of VBO prepregs and the SQRTM and PCM processes reach properties very close to autoclave ones. Porosity is usually slightly higher than in an autoclave (approx. 1–2% versus below 1%), which does not matter for many applications.
When is OOA cheaper?
When there is no need to invest in an autoclave, the part is large, or the series justifies a press with a short cycle. Savings also come from lower energy use and fewer consumables.
External data sources: Wikipedia – Out of autoclave composite manufacturing; Gardner – AirPower / BACM, Maserati MC20.
Other technologies
Need help choosing?
Send us a description of the part and the planned quantity – we will propose the process and explain why.
Have a drawing or just an idea? We will tell you how to make it.
Tell us what the part has to do, how many you need and what the requirements are. We will reply with a proposed process, material and next steps – with no obligation, under NDA if needed.