Abstract: One embodiment of a heated nozzle for extruding meltable material consists of an electrically conductive nozzle, comprised of an inlet, an outlet, and a passage connecting inlet and outlet. The nozzle fits into a hole or gap cut or formed through a loop of high permeability soft magnetic material such as ferrite or pressed iron powder. Electrically conductive wire is coiled around and through this magnetic loop to form a coil. A high-frequency alternating current is supplied to the coil, inducing a magnetic field in the magnetic core. The magnetic field, when passing through the electrically conductive nozzle, induces eddy currents that heat the nozzle to melt the material entering the inlet.

Abstract: An improved hybrid variable reluctance linear forcer design of the type known as a Sawyer motor forcer is provided with a 6-phase magnetic design. The 6-phase magnetic design has reduced force ripple compared to existing 2/4-phase and 3-phase designs providing smoother motion with lower velocity ripple. Three identical electromagnets each having four salient toothed poles with each pole being spaced at a unique 30 degree phase increment form a 12-pulse force function equivalent to a 6-phase motor. The electromagnets are provided with split-phase windings, which enable balanced 3-phase amplifiers to drive 6-phase coils.

Abstract: A digitally controlled, integrated Sawyer motor forcer consists of a rigid mechanical housing containing one or more linear motor segments, integrated control electronics, cooling means, and optional feedback sensors. The integrated control electronics include digital processing circuits, an external host communication interface, power conditioning and supply circuits, forcer phase amplifiers, input/output circuits and optional feedback sensor circuits. The integrated controller also provides control, amplifier, input/output, and sensor circuits for additional external motor axes that may be attached to the forcer as needed for specialized machines. The forcer may be operated in an open-loop mode without feedback sensors, or in a closed-loop servo mode using integrated feedback sensors of various types. Cooling means are included in the forcer to reduce the temperature rise caused by power dissipation in the forcer coils and the integrated electronic elements.

Abstract: An imaging system for a linear motor that provides information concerning movement of the same along a plurality of directions, with the information concerning motion along any one direction being substantially unaffected by motion of the motor in a differing direction. In this fashion, a plurality of detectors may be mounted onto the rotor of the linear motor to sense movement along a particular direction, with the detector being insensitive to motion of the motor along a differing direction. The system includes a substantially planar surface, such as a platen, having disposed thereon a pattern forming a two dimensional grid-like array.