Three-dimensional printer with cooled protective sheet separator

A three-dimensional printer for building a three-dimensional object by sequential deposition and heat treatment of a plurality of cross-sectional layers, the printer comprising:

• a material bed for supporting the plurality of cross-sectional layers;
• a print mechanism movably mounted in a print direction over the material bed, the print mechanism comprising:
• a temperature regulating element in thermal communication with the material bed to control the temperature of an uppermost layer of deposited material;
• a recoater for spreading a layer of flowable green material on the material bed, the recoater being located after the temperature regulating element in the print direction;
• and
• a print head arranged to transfer thermal energy by conduction to the layer of flowable green material on the material bed, the print head being located after the recoater in the print direction;
• a protective sheet located over the material bed in between the uppermost layer of material on the material bed and the temperature regulating element and in between the layer of flowable green material and the print head,
• wherein the print mechanism includes a separator located before the recoater in the print direction, the separator being arranged to separate the protective sheet from the uppermost layer of deposited material to provide access for the recoater to spread the layer of flowable green material on to the uppermost layer of material on the material bed,
• wherein the separator has a cooling surface in thermal communication with the uppermost layer of deposited material, the cooling surface being at a lower temperature than the temperature of the temperature regulating element;
• and
• a coolant distribution circuit arranged to deliver a supply of coolant into the separator.

A three-dimensional printer, comprising:

• a material bed to support a flowable green material;
• a print head arranged to transfer thermal energy by conduction to green material on the material bed;
• a protective sheet to protect the print head from direct contact with green material on the material bed;
• a separator arranged to separate the protective sheet from green material on the material bed, the separator having a cooling surface to cool green material on the material bed;
• and
• a cooling mechanism to actively cool the separator cooling surface.