Autoclave Technology

In compos­ite tech­no­logy, auto­claves are pres­sure vessels used to process parts and mater­i­als which require expos­ure to elev­ated pres­sure and temper­at­ure for the curing. The pres­sure is neces­sary to reach a suffi­cient level of fiber content and to reduce the resid­ual poros­ity in the compos­ites. Parts processed in an auto­clave are often vacuum bagged to enable the pres­sure to oper­ate isostat­ic­ally on the work­pieces. In simplest form, the work­load is fully contained inside a loosely-fitting bag made of resi­li­ent plastic. When vacuum is drawn, the bag is compressed by atmo­spheric pres­sure and compacts the compon­ents inside. Between the parts and the bag, an absorb­ent mater­ial (bleeder) provides a chan­nel for the evac­u­ation of the air and wicks up the excess resin squeezed out during curing.

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The compos­ite depart­ment of AAC oper­ates an auto­clave from the company “Scholz GmbH” to manu­fac­ture molded compos­ite struc­tures. Rated at 10 bar and 300°C, the auto­clave allows us to process high temper­at­ure epoxy, prepregs and ther­mo­plastic mater­i­als.

An autoclave process sequence is performed as follow:
  • Prepare plies
  • Stack plies in tool
  • Add dry mater­ial to absorb excess resin and remove volat­iles
  • Apply vacuum bag & cure in auto­clave
  • Oven post-cure for envir­on­mental durab­il­ity
  • Trimming
  • Inspection

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Autoclave prop­er­ties:

  • Length: 1 m
  • Diameter: 50 cm
  • Maximal temper­at­ure: 300°C
  • Maximal pres­sure: 10 bar
  • Vacuum connec­tions for bagging
  • Cooling system for temper­at­ure control