Hand Lay-Up
“Hand lay-up is the simplest and oldest open molding method of the composite fabrication processes. It is a low volume, labor intensive method suited especially for large components, such as boat hulls. Glass or other reinforcing mat or woven fabric or roving is positioned manually in the open mold, and resin is poured, brushed, or sprayed over and into the glass plies. Entrapped air is removed manually with squeegees or rollers to complete the laminates structure. Room temperature curing polyesters and epoxies are the most commonly used matrix resins. Curing is initiated by a catalyst in the resin system, which hardens the fiber reinforced resincomposite without external heat. For a high quality part surface, a pigmented gel coat is first applied to the mold surface.”
Engineers Handbook, 9/21/2010
Recent US Patents
12/19/2010
7,807,005
Fabrication process for thermoplastic composite parts
Rubin, Fox and Wilkerson of the Boeing Company, Illinois formed a thermoplastic composite laminate material with tailored and varying thickness in a continuous process. Automated equipment or hand lay-up is used to collate parts or components into a multi-layer stack. The consolidation tooling contains all necessary part features and is coordinated to the customized multiple ply stacks to form a single integrated thermoplastic composite laminate potentially having areas of differing thickness from these multiple ply stacks. (RDC 12/19/2010)
12/19/2010
7,807,002
Verification of tow cut for automatic fiber placement
Englebart and Hannebaum of the BoeingCompany, Illinois monitor the tow cutters in an automatic fiber placement machine by a machine vision system. (RDC 12/19/2010)
8/3/2010
7,767,128
Apparatus and methods for forming composite stiffeners and reinforcing structures
Benson et al has developed a method for making curved composite stiffners by pressing preimpregnated plies over a curved mandrel. (RDC 9/14/2010)
7/20/2010
7,758,800
System and method for resin infusion
Cicci, Davie and Singleton of Comtek Advanced Structures have improved resin infusion by controlling the vacuum using sensors to monitor flow within the mold. (RDC 9/24/2010)
Recent Journal Articles
10/29/2010
Influence of core fillers on resin flow and fiber compaction of cocured skin-to-stiffener structures
(pages 1360–1368)Polymer Composites 31 #8 (2010)
Wang et al studied experimentally the integral technology of cocuring was of T-stiffened skins. A new application of transferring pressure film was carried out to measure the pressure distribution in T-stiffeners. The results indicated that nonuniform pressure in T-stiffeners, especially in the corners existed. Resin-rich defect and highest thickness developed in the stiffener corners. However, rolling unidirectional prepregs as fillers into the stiffener corners led to a significant increase in the fiber compaction and manufacturing quality of T-stiffeners. (RDC 12/15/2010)