Apparatus, systems and methods for use in three-dimensional printing

A three-dimensional printing machine comprising:

• a powder presenter configured to repeatedly present a supply of powder;
• a build bed assembly configured to receive sequential layers of powder for building a product, the powder presenter and the build bed assembly being aligned in a working direction;
• and
• a roller assembly comprising:
• an elongated roller configured to spread powder from the powder presenter to the build bed assembly;
• and
• a pair of sliders coupled to the roller assembly and projecting from the roller assembly in the working direction, the sliders being spaced apart from each other by a distance selected to prevent powder from escaping laterally from the build bed assembly as the powder is spread from the powder presenter to the build bed assembly;
• wherein the build bed assembly comprises perimeter walls having top surfaces, and wherein the sliders are spaced to slide along the top surfaces of the perimeter walls of the build bed assembly during operation.

A roller assembly for a three-dimensional printing machine having a powder presenter configured to repeatedly present a supply of powder and a build bed assembly configured to receive sequential layers of powder for building a product, the powder presenter and the build bed assembly being aligned in a working direction, the roller assembly comprising:

• an elongated roller configured to spread powder from the powder presenter to the build bed assembly;
• a pair of sliders coupled to the roller assembly and projecting from the roller assembly in the working direction, the sliders being spaced apart from each other by a distance selected to prevent powder from escaping laterally from the build bed assembly as the powder is spread from the powder presenter to the build bed assembly;
• and
• a motor coupled by a flexible transfer member to the roller to controllably rotate the roller with respect to the roller assembly, and a tensioning member coupled to the motor and roller to adjust the tension of the flexible transfer member.

A roller assembly for a three-dimensional printing machine, the three dimensional printing machine having a powder presenter configured to sequentially present supplies of powder and a build bed configured to receive sequential layers of powder for building a product, the powder presenter and build bed being aligned in a working direction, the roller assembly comprising:

• a carriage configured to controllably move in the working direction with respect to the three-dimensional printing machine;
• a roller assembly having a roller movably coupled to the carriage to move with respect to the three-dimensional printing machine to change a vertical spacing between the roller and the build bed;
• a motor coupled by a flexible transfer member to the roller to controllably rotate the roller with respect to the roller assembly, and
• a tensioning member coupled to the motor and roller to adjust the tension of the flexible transfer member.