Films, foils, or adhesives may be interleaved while fiber-placing composite material structures.
An automated apparatus has been designed and constructed that enables the automated lay-up of composite structures incorporating films, foils, and adhesives during the automated fiberplacement process. This apparatus, denoted a film module, could be used to deposit materials in film or thin sheet form either simultaneously when laying down the fiber composite article or in an independent step. Examples of materials that may be processed with this device include structural core and joining adhesives, permeation barrier films/foils, surfacing films, lightning-strike materials and IVHM (Integral Vehicle Health Monitoring) arrays. The use of this technology will reduce composite fabrication time and will allow for new concepts/ designs to be considered for fiber-placed composite structures.
The film module may be easily designed to fit existing fiber-placement machinery or may be integrally designed into new machines. The film materials may be placed either simultaneously with the fiber composite material as with the case of embedded materials, or in an independent operation as with application of exterior structural core adhesives, as shown in the figure. The device is designed such that it may be made to operate by use of existing fiber-placement lay-up program files. This eliminates the need for additional computer program files to be generated, saving both time and expense.
The film module includes a material supply and feed system, a material preheating system for the tackifying of incoming and substrate materials, and a film-cutting system. The preheating system utilizes an infrared quartz-halogen lamp with a focused parabolic reflector to provide radiant heating of the substrate and incoming materials at the point of application. All prototype device actuators are pneumatic; however, digital servo/stepper motors may be employed for additional control and accuracy.
The prototype device was designed to supply material of width identical to that of the composite material typically processed by the machine that was used as the test-bed during the course of module development. By thus setting the width of the film, use may be made of the same placement files as written for the composite. The device is designed to be portable and easily removed from the host machine. A simple switch allows for the disabling of the device when placement of composites alone is being performed.
This work was done by A. Bruce Hulcher of Marshall Space Flight Center. For further information on this technology, contact A. Bruce Hulcher at (256) 544-5124.