The use of3-D LCVD with volumetric rate feedback was investigated in the fabrication
ofmicromechanical wall structures. These were constructed by recursive laser scanning and
resulted in layered wall composed ofrecursive line deposition.
Experiments were designed to uncover the relationship between scan rate, volumetric deposition
rate, pressure and laser powerfor pyrolytic graphite from an ethylene precursor. Results point to
a conduction dominated heat transfer which greatly limits the volumetric deposition rate at the
wall. This also results in a highly unstable deposition process, since volumetric deposition
increases by orders ofmagnitude as soon as rod growth is initiated.
An unexpected results ofthis work is the ability to grow rods at an angle to the laser axis, with
good control ofthe linear growth rate. This is achieved by adaptive laser scanning during rod
growth.Mechanical Engineerin
