Abstract: A method of 3D printing a part with an extrusion-based additive manufacturing system includes providing a filament having a semi-crystalline material as a majority component of a polymeric matrix to a liquefier having a liquefier tube having an overall length between an inlet end and an outlet end. An upper portion of the liquefier tube adjacent the inlet end has a first length and a first cross-sectional area substantially perpendicular to a longitudinal axis and a lower portion of the liquefier tube adjacent the outlet end has a second length and a second cross-sectional area substantially perpendicular to the longitudinal axis, wherein the first cross-sectional area is greater than the second cross-sectional area. The method includes driving the filament into a melt zone located within the upper portion of the liquefier tube at a selected rate based upon a desired extrusion rate. The filament is melted within the melt zone forming a melt pool in the liquefier tube to provide the selected extrusion rate.

Abstract: A method of 3D printing a part with an extrusion-based additive manufacturing system includes providing a filament having a semi-crystalline material as a majority component of a polymeric matrix to a liquefier having a liquefier tube having an overall length between an inlet end and an outlet end. An upper portion of the liquefier tube adjacent the inlet end has a first length and a first cross-sectional area substantially perpendicular to a longitudinal axis and a lower portion of the liquefier tube adjacent the outlet end has a second length and a second cross-sectional area substantially perpendicular to the longitudinal axis, wherein the first cross-sectional area is greater than the second cross-sectional area. The method includes driving the filament into a melt zone located within the upper portion of the liquefier tube at a selected rate based upon a desired extrusion rate. The filament is melted within the melt zone forming a melt pool in the liquefier tube to provide the selected extrusion rate.

Abstract: Disclosed is a modeling filament for use as feedstock in a fused deposition modeling liquifier, and a method for manufacturing the filament. The diameter and standard deviation of the filament are controlled to meet various tolerance requirements of jam resistance, slip resistance, model strength, liquifier overflow prevention and hysteresis-free transient response. Standard deviation of the filament diameter is matched to a filament target diameter. The resulting filament is used to form high-quality models.

Abstract: A microwave grain monitor determines grain density and moisture content without measuring the phase shift of the measurement signal in passing through the grain. A set of grain coefficients is determined and stored in a non-volatile memory. A microwave measurement signal is transmitted through the grain and the ambient temperature is sensed. The grain density and moisture content are determined from the attenuation of the measurement signal in passing through the grain, the sensed temperature and the set of grain coefficients.

Abstract: A microwave grain monitor determines grain density and moisture content without measuring the phase shift of the measurement signal in passing through the grain. A set of grain coefficients is determined and stored in a non-volatile memory. A microwave measurement signal is transmitted through the grain and the ambient temperature is sensed. The grain density and moisture content are determined from the attenuation of the measurement signal in passing through the grain, the sensed temperature and the set of grain coefficients.