Multiple beams and nozzles to increase deposition rate

Abstract

A method has been developed to exploit the desirable material and process characteristics provided by a low powered laser material deposition system, while overcoming the low material deposition rate imposed by the same process. One application of particular importance for this invention is direct fabrication of functional, solid objects from a CAD solid model This method of fabrication uses a software interpreter to electronically slice the CAD model into thin horizontal layers that are subsequently used to drive the deposition apparatus. The apparatus uses a single laser beam to outline the features of the solid object and then uses a series of equally spaced laser beams to quickly fill in the featureless regions. Using the lower powered laser provides the ability to create a part that is very accurate, with material properties that meet or exceed that of a conventionally processed and annealed specimen of similar composition. At the same time, using the multiple laser beams to fill in the featureless areas allows the fabrication process time to be significantly reduced.

We claim:  
     
         1 . A direct material deposition method comprising the steps of: 
 a. providing a powdered material that can be melted by a laser beam;    b. providing a laser nozzle assembly having multiple laser beams coupled with said powdered material from a set of powder nozzles directed to approximately the same location;    c. positioning a deposition substrate adjacent to the laser deposition head outlets;    d. melting said powdered material with said laser beam; and    e. providing relative motion between the laser deposition apparatus and said deposition substrate.    
     
     
         2 . The method of  claim 1 , wherein said powdered material is melted with said laser beams, whereby the melted powdered material is fused to a substrate to create a thin layer of material.  
     
     
         3 . The method of  claim 1 , wherein said powdered material is vaporized with said laser beams, whereby the vaporized powdered material is deposited onto the substrate to create a thin layer of material.  
     
     
         4 . The method of  claim 1 , wherein said relative motion derives from a CAD model.  
     
     
         5 . The method of  claim 4 , wherein a single laser beam can be used to outline features defining surfaces of an object under construction.  
     
     
         6 . The method of  claim 4 , wherein said multiple laser beams are used to fill the featureless regions defining the surfaces of said object.  
     
     
         7 . The method of  claim 1 , wherein said laser beams are controlled individually, whereby one or more of the beams may be modulated on and off during any part of the deposition process to create one or more line deposits simultaneously.