The elastic instability of fountain flows

In order to elucidate the mechanism that causes flow mark surface defects, the stabihty of the fountain flow during injection molding is investigated numerically using a transient finite element method. Using a single mode extended Pom-Pom model we demonstrate that the fountain flow instabiUty is an elastic instability

Polyester powders and the use thereof in three-dimensional printing procesess

The present invention is directed to polyester powders suitable for use in 3D printing processes, methods of using such polyester powders in 3D printing processes, and processes for the manufacturing thereof. The polyester powders prepared in accordance with the present invention are easily recycled after such polyester powders have been subjected to 3D printing conditions. In addition, the present invention is directed to recycling processes that recondition waste polyester powders into polyester powders suitable for 3D printing

Compositions and methods for high-temperature jetting of viscous thermosets to create solid articles via additive fabrication

Described herein are methods and compositions for forming three-dimensional objects via material jetting processes, the methods including the repeated steps of selectively depositing a liquid thermoset material onto a surface from a nozzle of at least one jetting head in a first specified direction and exposing at least a portion of the liquid thermoset material to a source of actinic radiationin order to form a three-dimensional object from the cured thermoset material, wherein the jetting head is configured to eject droplets of o the liquid thermoset material from the nozzle at prescribed elevated operating temperatures, and wherein the liquid thermoset material is chosen so as to possessing prescribed viscosity and rheological characteristics.<br/