Construction

The Construction


Built using both vacuum and conventional laminating techniques, the Kahu boasts the highest grade materials specifically for it’s design tasks. The composite core sandwich of the Kahu is at the leading edge of currently available products.

 

Here’s why we chose this advanced and Patented, core material…

 

The special core itself is the combination of light hollow microspheres with high-modulus fibers. Thermoplastic microspheres are embedded within the high-modulus fibers in form of a watery suspension at the unexpanded preliminary stage so that the individual particles are evenly distributed right into the interior area of the elementary fiber strands. These non-bloated filler particles are subsequently expanded through a thermal process. This causes the elementary fibers to expand, adding volume to the fiber strands in a definable form up to 100 times their basic volume. Through the unique combination of extremely light, tough-plastic microspheres and the superior strength characteristics of high-modulus fibers, the core laminates are imparted material characteristics, which are not generally achieved by the classic composite materials. The flat core products manufactured in this way are between 1-12mm thick. These material thicknesses can be adjusted as required through the construction of basic materials, quantity and quality of the thermoplastic microspheres and the production parameters. At the same time the strength characteristics can be adjusted to the desired application through the quality of the high-modulus fibers and high or low fiber contents. The weight characteristics and the resin absorption can also be modified as required through higher or lower concentrations of microspheres. These core products can also be adapted to the various further processing technologies through different material structures and quality of the microspheres.

With most of the known core materials (such as plywood, BALSA, foam materials, honeycomb, etc.) the achievable weight savings are at the expense of serious quality restrictions and manufacturing problems of the sandwich laminates manufactured from these materials. These are

Plywood:


  • High weight
  • Not drapeable
  • Bad bond strength = poor sheer strength
  • No laminate homogeneity
  • Hygroscopic = rotable = bad long term performance
  • High processing cost
  • Only available as panels with limited lengths and widths
  • Poor impact strength
  • Only suitable for limited processing methods
  • Difficult to repair

BALSA:


  • Poor drapeability: Can be shaped to a minor extent only through chessboard type “block structure”
  • Low bond strength = poor shear strength
  • No laminate homogeneity
  • Hygroscopic = rotable = bad long term performance
  • Complex and consequently expensive processing
  • Only available as panels with limited lengths and widths
  • Poor impact strength
  • Low compression strength
  • Only suitable for limited processing methods
  • Difficult to repair

Foam materials


  • Poor drapeability: Can be shaped to a minor extent only through chessboard type “block structure”
  • Low bond strength = poor shear strength
  • No laminate homogeneity
  • High processing costs
  • Only available as panels with limited lengths and widths
  • Very low compression stability
  • Low temperature resistance
  • Only suitable for limited processing methods
  • Difficult to repair

Honeycomb


  • Limited drapeability
  • Limited bond strength
  • No laminate homogeneity
  • Open honeycomb structures = susceptible to injury = water absorption
  • Very expensive to process
  • Only suitable for limited processing methods
  • Difficult to repair
The Patented CORE product used in the manufacture of the KAHU has…
  • Good drapeability = can be laminated even with extreme three-dimensional shaping
  • High bond strength = excellent sheer strength
  • Unique laminate homogeneity through wet in wet manufacture of the total laminate
  • Can be used in almost all popular working processes (hand lay-up, spray up, wet winding, pultrusion, wet pressing, vacuum process, RTM, injection process)
  • Print blocking = excellent surfaces
  • The best surface qualities of all currently known manufacturing processes for composite materials are possible with this product.