Three dimensional printing system

A method of fabricating a three dimensional object with a three dimensional printing system, the method comprising:

• forming a layer of build material;
• with a moveable carriage comprising a print head, selectively depositing a printing agent on to the layer of build material as the moveable carriage is moved relative to the layer of build material, the printing agent controlling localized fusing of the build material on application of energy;
• with a print controller communicatively coupled to an array of laser modules, individually controlling the array of laser modules to selectively apply energy to sub-regions of the layer of build material in accordance with the selective deposition of the printing agent, wherein each laser module comprises a laser stack, the laser stack comprising a plurality of laser bars, each laser bar comprising a plurality of laser diodes, each laser bar being positioned between two metal parts that function as electrodes and dissipation heatsinks for each laser bar;
• and
• wherein the print controller is configured to control activation of individual laser modules of the array of laser modules so as to apply, selectively, energy to addressable sub-regions of the layer of build material on which printing agent has been deposited to control fusing together with the deposited printing agent;
• wherein the application of energy to the sub-regions enables localized fusing of build material where printing agent is deposited to fabricate a layer of the three dimensional object.

A non-transitory machine readable medium comprising instructions which, when loaded into memory and executed by at least one processor, cause the processor to:

• obtain data representative of a three dimensional object;
• generate, based on the data representative of the three dimensional object, print control data to control a print head of a three dimensional printing system, the print control data controlling the selective deposit of a printing agent at a plurality of locations on a layer of build material, the printing agent controlling localized fusing of the build material on application of energy;
• generate, based on the print control data, power supply signals for each laser module in an array of laser modules to apply, selectively, energy to addressable sub-regions of the layer of build material on which print agent has been deposited, wherein each laser module comprises a laser stack, the laser stack comprising a plurality of laser bars, each laser bar comprising a plurality of laser diodes, each laser bar being positioned between two metal parts that function as electrodes and dissipation heatsinks for each laser bar;
• and
• operate a moveable carriage comprising a print head arranged to selectively deposit a printing agent on to a layer of build material as the moveable carriage is moved relative to the layer of build material, the printing agent controlling localized fusing of the build material on application of energy;
• wherein the processor is communicatively coupled to the array of laser modules and configured to control activation of individual laser modules of the array of laser modules so as to apply, selectively, energy to addressable sub-regions of the layer of build material on which printing agent has been deposited to control fusing together with the deposited printing agent.