System and Method for Determining Beam Power Level Along an Additive Deposition Path

摘要

A power schedule calculation method utilizes an idealized geometry to predict laser power levels on an additive path during laser deposition. The method calculates beam power for any point along the path traveled to form a build having a geometry. Each point along the path has associated with it an idealized geometry comprising a melt pool, hot zone and bulk portion. The method comprises creating a geometric description representing the geometry of the build during the process, creating a path description representing the path of the beam source through space during the process, calculating the idealized geometry for the point on the path based upon the geometric description and path description, calculating an energy balance at the melt pool for the point on the path, calculating total energy needed at the point on the path and calculating optimum beam source power. In the calculations, build temperature is based upon a calculation of hot zone temperature derived from the idealized geometry.

主权项

1. A power schedule calculation method for an additive deposition process using a beam source that calculates optimum beam power for any point P(s) along an additive path that will be traveled to form a build, the build having a geometry and being formed from deposited material added to a structure, the point P(s) along the additive path having associated with it an idealized geometry comprising a melt pool, hot zone and bulk portion, the method comprising:
1) creating a geometric description representing the geometry of the build during the additive process; 2) creating a path description that represents the path of the beam source through space during the additive process; 3) calculating the idealized geometry for the point P(s) on the additive path based upon the geometric description and path description; 4) calculating an energy balance at the melt pool (EBmelt pool) for the point P(s) on the additive path, the energy balance calculation being based upon the following calculations:
a) a calculation of energy radiated from the melt pool (Hrad);b) a calculation of energy conducted from the melt pool to the hot zone (Hcond), the calculation of Hcond being based upon the calculated idealized geometry andc) a calculation of energy lost due to convection at the melt pool (Hconv); 5) calculating total energy (Htotal) needed at the point P(s) on the additive path according to the following equation
Htotal=Hdeposited material+Hremelt+EBmelt pool wherein Hdeposited material represents energy required to melt the deposited material and Hremelt represents energy required to remelt existing material; 6) calculating optimum beam source power Qsouce for the point P(s) according to the following equation
Qsource=min(Qmax, Htotal/αΔt) wherein Qmax represent maximum laser power, α represents a beam absorption coefficient and Δt represents a calculation interval.