System and method for high power diode based additive manufacturing

#The present disclosure relates to Additive Manufacturing systems and techniques for making three dimensional articles and parts, and more particularly to a system and method for performing Additive Manufacturing using a high power diode system.

#The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

#Additive Manufacturing (“AM”), also referred to as 3D printing, is a manufacturing technique in which material is added sequentially, layer by layer, in order to build a part. This is in contrast to traditional machining, where the part starts as a block of material that is then whittled down to the final desired shape. With AM fabrication, a directed power source is used to agglomerate material (typically powder) into a final, near net-shape article. Three dimensional articles are manufactured one layer at a time as an assemblage of two-dimensional sections. One important advantage of AM fabrication is that complex shapes (e.g. parts with internal features) can be realized. Another important advantage is that the material required is limited to that used to form the final part. Thus, AM fabrication has the benefit of very little material loss. This is especially important for expensive/tightly controlled materials.

#The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In the drawings:

#FIG. 1 is a diagrammatic view of one embodiment of the present system and method for performing an Additive Manufacturing (“AM”) fabrication process using a high power diode array and a mask;

#FIG. 2 is a diagrammatic side view of the system of FIG. 1 showing how a portion of the optical rays from the diode array are reflected by a polarizing mirror during the fabrication process to prevent them from reaching the substrate;

#The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

#Referring to FIG. 1 a system 10 is shown in accordance with one embodiment of the present disclosure for performing an Additive Manufacturing (“AM”) fabrication process. The system 10 may include a high power diode array 12 and a computer controlled, selective area mask 14 (hereinafter simply “mask 14”). A suitable power supply 16 may be used for providing electrical power to the diode array 12. A computer 18 or other suitable form of processor or controller may be used for controlling the power supply 16 to control the on/off application of power to the diode array 12 as well as selectively (i.e., digitally) controlling the mask 14 and shaping or focusing the optical beam. Optionally, separate processors or computers may be used to control the diode array 12 and the mask 14. Selectively electronically controlling the mask 14 with the computer 18 allows the optical beam from the diode array 12 to be prevented from reaching specific selected portions of powder that forms a substrate 20 (i.e., powder bed) so that those portions are irradiated by the beam. In FIG. 1 portion 15 is cross hatched to represent a portion of the output from the diode array 12 that does not reach the powdered material of the substrate 20.

#In one preferred form the diode array 12 may comprise a single large diode bar. Alternatively a plurality of diode bars located adjacent one another may be used to form the diode array 12. In one preferred form the diode array may be made up of arrays of diode bars each being about 1 cm×0.015 cm to construct a 25 cm×25 cm diode array. However, any number of diode bars may be used, and the precise number and configuration may depend on the part being constructed as well as other factors. Suitable diode bars for forming the diode array 12 are available from Lasertel of Tucson, Ariz., Oclaro Inc. of San Jose, Calif., nLight Corp. of Vancouver, Wash., Quantel Inc. of New York, N.Y., DILAS Diode Laser, Inc. of Tucson, Ariz., and Jenoptik AG of Jena, Germany, as well as many others. The diode array 12 is able to provide a minimum power density of about 10 kW/cm2 and maximum>100 kW/cm2 at two percent duty cycle. This makes it feasible to generate sufficient optical power to melt a wide variety of materials. FIG. 3 provides a table of the average power flux that has been calculated to melt various types of materials. FIG. 4 shows a graph that illustrates the effectiveness of the diode array 12 on a variety of metal powders (i.e., Aluminum, Titanium, Iron and Tungsten), at a power flux sufficient to melt all the materials. The calculations to obtain the graphs shown in FIG. 4 were performed in MATLAB with conductive and radiative losses taken into account. A conservative 30% absorptivity was assumed along with a powder layer thickness of 100 μm.