Among the most pressing problems in molecular manufacturing
research today is devising means to construct atomically precise
moving parts under programmable control, in other words, building
the components essential to the operation of an assembler.
Several strategies for doing this have been proposed, including
protein engineering, scanning probe microscope (SPM) placement of
building blocks via antibody grippers, and ambient or vacuum
placement of surface bonded building blocks or individual atoms.
Construction not only of static three dimensional structures is
required, but also that of tight, non-reactive sliding interfaces
to make up bearings, actuators and other articulating components.
A prime constraint in constructing atomically precise
interfaces is the limitation to the operations of a single
sub-angstrom positioning device. Unlike conventional
manufacturing where multiple arms can fit objects into interfaces
in three dimensions, products made by SPM must be mostly
layer-by-layer constructions. A similar constraint can be seen in
autofab laser resin curing, where a scaffolding must be built up
around moving parts to immobilize them. To produce interfaces
where the space between parts is measured in tenths of an
angstrom it seems necessary both to be able to continuously add
and remove small interface joiners or spacers during the
construction process, and to fit intermediate parts into holes
and bond them using these joiners. Schemes for addition and
removal of joiners in ambient and vacuum conditions will be
presented, as well as methods for fitting components with only
one positional device, while retaining imaging capability. These
considerations are discussed in a proposed construction of a
double tripod positional device by SPM based mechanosynthesis.
James R. Von Ehr II, 251 West Renner Parkway, Suite 166,
Richardson, TX 75080, ph: 972-235-7881, fax: 972-235-7882, email: