System for 3D printing

1. An additive manufacturing (AM) system comprising:

a carriage comprising:

a printing block comprising a plurality of slots for receiving a plurality of printing heads;

a pre-heating assembly comprising a plurality of pre-heating chambers, wherein the pre-heating assembly is mounted on the printing block and wherein the carriage includes more pre-heating chambers than slots; and

wherein the printing block is formed with a pair of reservoirs surrounding each of the plurality of slots and wherein each reservoir of the pair of reservoirs is configured to be in fluid communication with one of the plurality of pre-heating chambers and includes at least one outlet configured to direct material from the printing block to one of the plurality of printing heads installed in one of the plurality of slots;

wherein each of the plurality of printing heads that is configured to be installed in the slots includes two nozzle arrays and is configured to receive material from the pair of reservoirs and to dispense the material from each reservoir with a separate nozzle array; and

a building platform configured to receive material deposited from the carriage.

2. The AM system of claim 1 , wherein each of the plurality of pre-heating chambers is in fluid communication with one of the reservoirs formed in the printing block.

3. The AM system of claim 1 , wherein the pair is separated by a separating wall and wherein the separating wall is configured to allow selected flooding between the pair of reservoirs.

4. The AM system of claim 1 , wherein the plurality of printing heads is configured to simultaneously receive material from all the plurality of pre-heating chambers.

5. The AM system of claim 1 , comprising heating plates installed on two opposite facing surfaces of the printing block.

6. The AM system of claim 1 , wherein at least one of the plurality of pre-heating chambers includes a worm screw channel configured to direct material through the one of the plurality of pre-heating chambers and where the worm screw is formed from a heat conductive material.

7. The AM system of claim 1 , wherein the material is directed from a pre-heating chamber to a printing head reservoir via a dedicated block cover channel and wherein each of the plurality of pre-heating chambers includes a worm screw.

8. The AM system of claim 1 , wherein the carriage includes a hardening unit configured to harden a layer of material dispensed on the building platform.

9. The AM system of claim 1 , wherein the carriage includes a leveling device configured to level a layer of material dispensed on the building platform.

10. The AM system of claim 1 , where the AM system is a three dimensional ink-jet printer.

11. The AM system of claim 1 , wherein the pre-heating assembly is divided into a first section including a first pre-heating chamber and a second section including a second plurality of pre-heating chamber, wherein the first section is pre-heated with a first heating element and wherein the second section is heated with a second separate heating element.

12. The AM system of claim 1 , wherein the printing block includes a least one reservoir associated with each of the slots and wherein the printing block includes openings that are configured to thermally insulate material received in one of the reservoirs from material received in other reservoirs of the printing block.

13. The AM system of claim 1 , wherein the pre-heating assembly is divided into at least a first section and a second section, wherein the first section includes a first pre-heating chamber and the second section includes a second pre-heating chamber, and wherein the first section is pre-heated with a first heating element and the second section is heated with a second separate heating element.