Pultrusion - Dry reinforcement layers are typically wetted in a resin bath then pulled through a heated constant cross section die defining the part shape.  A continuous part is formed as the wetted reinforcement is consolidated and cured in the die section.  The pultruded shape is cut to desired part lengths after exiting the die.

 

Table Rolling - Hotmelt prepreg strips are layered and rolled around a male mandrel defining the part's inside shape.  A spiral overlapped wrap of heat shrink tape is tightly wrapped over the prepreg layup.  The wrapped part is placed in an oven or heated by other means to shrink the tape and consolidate the prepreg layers against the mandrel surface.  After cooling the shrink tape is removed and the mandrel is extracted (pulled) from the cured part interior.

Hollow Composite Part Manufacturing

 

Bladder Molding Advantage

       Sourcing

              Solutions

BIM allows composite designers and producibility engineers to consider complex hollow shapes either impossible or too expensive to produce by Pultrusion and Table Rolling

BIM supports hotmelt prepreg processing and resin infusion of dry fiber preforms (e.g., VARTM, RTM)

BIM is an affordable choice for high volume production of small to medium size parts

Prepreg strips are layered to form the general part shape around an inexpensive (single use) thermoplastic or elastomeric (reusable) bladder.  In the case of open preforms the bladder may be inserted after part layup.  The hotmelt preform and bladder are then placed in a female mold defining the part shape.  The mold is closed and heated while inflating (expanding) the bladder to consolidate the prepreg layers against the mold surface.  After demolding the part the bladder is removed or left in the part (Bladder Molding Case Study).

BIM produces parts with excellent OML surface quality

Dry reinforcement plies are layered to form the general part shape around an inexpensive (single use) thermoplasticor elastomeric (reusable) bladder.  The dry preform and bladder are then placed in a female mold defining the part shape.  The mold is closed and the bladder is inflated to consolidate (debulk) the preform against the mold surface.  Resin is introduced under vacuum or positive pressure through strategically located mold ports.  The part is cure at room temperature or at elevated temperature by heating the mold.  After demolding the part the bladder is removed or left in the part.

Limited to Straight

Constant Cross Sections

Variable Cross Sections

Non-Linear Geometries

Next Product Challenge?

Curved Mating Segments

Limited to Straight Constant or Tapered Cross Sections