The moving primary 2 or 4-phase dual-axis linear stepper
motor consists of a moving forcer and a stationary platen.
The forcer is made of four single-axis coil assemblies. Two
of the forcer assemblies are mounted in series to provide
a thrust in the X direction and the other two are mounted
orthogonal (at 90 deg.) to the first two assemblies to provide
thrust in the Y direction. The forcer assemblies are encapsulated
in a hard anodized aluminum housing. The motor’s surface
is lapped to provide a flat surface for the air bearing. The
floating height of the air bearing is less than 25 µm
[0.001 in]. The forcer is available in eight sizes, depending
on the application’s
force requirements.
The platen is a photo-chemically etched steel plate that
is filled with epoxy and ground. Standard mounting holes are
provided on forcer and platen. The platen is available in
sizes up to 0.24m x 0.34m [36 in x 59 in]. Preload for the
bearing system is provided by the magnetic-attractive force
between the forcer and the platen. The customer must bring
power to the forcer with a cable, and provide the bearing
air supply.