Learning Forum

[Amunyasia]

I intend to run single bead simulation in Additive Science using already available experimental data and compare the simulation results to experimental results. nThe User Interface allows one to input a minimum scan value of 350mm/s but the experimental scan speeds used are lower than that.n1)Is it possible to input speed values that are less than 350mm/s? and if so,n2)What is the procedure?nThanks.n

[John Doyle]

With regards to the Additive Science Single Bead Simulation Scan Speeds, we document that it "…Must be between 350 and 2500 mm/sec. Defaults to 1000 mm/sec."nThe reason for this is related in part to the limitations of the approach in the Additive Science Simulation. From the Additive Users Guide (Print and Science),Overview of the Thermal Solver: ...The solver can predict lack-of-fusion porosity via the powder-solid state tracking but does not predict balling or keyhole phenomena. Other physical phenomena that are not explicitly modeled include:latent heat, surface tension effects, vaporization, plasma, and spatter.nWhile the doc does not specifically say it, there is potential at lower scan speeds for some of these issues that are not currently taken into account to begin to dominate.n

[John Doyle]

It has also been pointed out to me that by going below 350mm/s, if you don?t simultaneously lower laser power (below the minimum limit of 50W), then the meltpool will grow too large for the solution domain, throwing an error or making the solution invalid. nBut lowering the 50W limit is not necessarily the solution to this, because if we go slower and with less power, then we have a lower cooling rate which will make our material property assumptions less accurate, which speaks to the first comments I made earlier.n