Laminating system speeds repairs
of composite structures
Ken Cressy, Industry Manager Aerospace Products
Ciba-Geigy Formulated Materials Group, Los Angeles, CA
To respond to the increased need for fast, effective field repairs on the growing number of composite structures used on today's aircraft or other applications, Ciba has introduced a new laminating system. The product is formulated to provide easy handling, fast curing, and excellent performance.
Called Epocast® 52-A/B, the two-component epoxy laminating system is designed for use with either graphite or fiberglass fabrics. It features an easy-to-handle mixed viscosity of less than 4,000 cps at room temperature, and a 60-minute work life. The system also provides good cloth wet-out, and once the laminate is complete it cures quickly for either three hours at 150F (65C) or two hours at 200F (93C).
Cured Epocast 52-A/B produces composites with a high shear modulus and good hot/set properties. In addition, the system offers good resistance to moisture and aircraft-type fluids. The material is currently being qualified by Airbus, Boeing, and McDonnell Douglas, and is being tested for the CACRC composite repair specification.
To speak to a Ciba-Geigy applications engineer, call: (818) 247-6210.
Eliminate seals for ultra-low friction
Mark Gaberman, President Airpot Corp., Norwalk, CT
Ordinary air cylinders eliminate leakage via interference fits between the seal and piston rod, and between the piston and cylinder. The trade-off is higher starting friction, or stiction, and higher running friction.
However, a small air loss is not relevant for many applications. Instead, near frictionless operation is important. Airpel "Anti-Stiction" cylinders, therefore, offer ultra-smooth motion in exchange for a little air leakage.
Construction features a precision-fit graphite piston, which slides without lubrication inside a Pyrex® cylinder liner. A stainless-steel sleeve encases the glass liner, leaving an impact protection gap good enough to shield the glass even if the outside wall is dented.
A biaxially pivotable piston and air bearing principles also contribute to the air cylinder's extremely low starting and running friction. Rather than the rubber seals used in most air cylinders, the piston rides on air.
This feature, combined with the ability to handle forces from a few grams to 30 lbs or more, makes stictionless air cylinders particularly well suited to a) applications requiring smooth motion at ultra-low pressures, and b) moving lightweight objects or delicate loads at low or high speeds.
Other advantages of near frictionless air cylinders include:
* Accurate, repeatable force output.
* No change in performance over an operating temperature range of 85 to 302F.
* Clean operation and corrosion resistance. Exposed surfaces are stainless steel and nickel.
To speak with an Airpot applications engineer, call (203) 846-2021.
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