A method and apparatus for applying a polymer coating on an elongated
substrate, preferably an elongate intracorporeal device in the form of a
guidewire. An extrudable polymer cartridge is moved by a cartridge
advancement mechanism into a guide chamber which is heated at an end with
a die or orifice through which a desired portion of a guidewire may pass
and be coated. Parameters such as guide chamber temperature, pull speed
and force exerted by the cartridge advancement mechanism may be controlled
with a computer program in order to achieve repeatable results. The guide
chamber, extrudable polymer cartridge, die, and push tube may all be made
from polymer components which can be reused or disposed of after a single
use. The extrudable polymer cartridge may have a variety of configurations
including multiple layers of different materials, eccentric shapes,
multiple lumens for multiple elements to be drawn through and coated and
asymmetric disposition of different materials with respect to the
longitudinal axis as viewed in a transverse cross section which can give
bending properties having a preferred direction in the coated guidewire or
device.
