Allan J. Lightman

Development of a curved layer LOM process for monolithic ceramics and ceramic matrix composites

A novel rapid prototyping technology incorporating a curved layer building style was developed. The new process, based on laminated object manufacturing (LOM), was designed for efficient fabrication of curved layer structures made from ceramics and fiber reinforced composites. A new LOM machine was created, referred to as curved layer LOM. This new machine uses ceramic tapes and fiber prepregs as feedstocks and fabricates curved structures on a curved‐layer by curved‐layer basis. The output of the process is a three‐dimensional “green” ceramic that is capable of being processed to a seamless, fully dense ceramic using traditional techniques. A detailed description is made of the necessary software and hardware for this new process. Also reviewed is the development of ceramic preforms and accompanying process technology for net shape ceramic fabrication. Monolithic ceramic (SiC) and ceramic matrix composite (SiC/SiC) articles were fabricated using both the flat layer and curved layer LOM processes. For making curved layer objects, the curved process afforded the advantages of eliminated stair step effect, increased build speed, reduced waste, reduced need for decubing, and maintenance of continuous fibers in the direction of curvature.

rapid Product Realization

Rapid product realization is a new method of manufacturing prototypes based on optical and laser systems. These techniques shorten product cycle times and reduce costs. They present a host of opportunities for the optics and photonics communities.

Measurements of the refractive-index variations with temperature of a photomonomer.

The temperature dependence of the index of refraction of CIBATOOL XB5081, a commercial photomonomer commonly used for stereolithographic part building, is measured at wavelengths of 632.8, 514.5, and 488.0 nm.