Core fit and resin flow through the core are also critical considerations in achieving superior cosmetics. To ensure consistent core fit and flow, producers can utilize a kit cutter – a pre-marked, ready-to-place reinforcement and core kit cut and shaped specifically for the mold they are to be used in.
Finally, additional layers of reinforcement fabrics should be added after the core and tucked into radiuses with minimal wrinkles. Knitted fabrics provide better flow in the z-direction and typically lay flatter than woven fabrics, which reduces resin usage and opportunities for bridging. When multiple layers are used, staggering the overlaps one to one-and-a-half inches helps reduce prerelease, shrinkage and resin-rich areas. This step is crucial when infusing thick laminates in vacuum infusion processing.
With the dry lay-up complete and the part ready to be infused, it is important to work through a final pre-infusion checklist. The temperature should be above 60 degrees Fahrenheit (mold, reinforcement and resin), and a second drop test should confirm less than two-inch mercury (inHg) loss over five minutes. All material should be tucked into place, and feed and vacuum lines should be in the proper layout.
Having an established preproduction process can make the difference between good and great results. From before material is loaded into the mold until the part is ready to be infused, attention to detail is key and these steps can lead to better, more efficient and highly cosmetic products.
Scott Phillips is marketing manager for Vectorply. Email comments to sphillips@vectorply.com.
For more information on mold release and preparation, visit www.compositesmanufacturingmagazine.com, click on the Tech Talk tab and search “mold release.”
Disclaimer: Opinions, statements and technical information within the Tech Talk column are that of the authors. ACMA makes no warranty of any kinds, expressed or implied, with respect to information in the column, including fitness for a particular purpose. Persons using the information within the column assume all risk and liability for any losses, damages, claims or expenses resulting from such use.
This boat hull has superior cosmetics.
Photo Credit: Cobalt Boats
