4.3. Wizard Step 2: Build Settings (for Thermal-Structural Simulations)

In the Build Settings step:

Simulation assumptions are set by default based on your chosen AM LPBF system.
Enter calibration factor(s) as determined from calibration experiments. Use default calibration factors if your goal is simply to examine trends, that is, the effects of variable changes on stress or distortion relative to each other.
Enter machine settings, which are process parameters that directly influence how the process deposits material. These include Deposition Thickness, Hatch Spacing, Scan Speed, and a number of other factors.
Enter build and cooldown conditions, which are settings pertaining to the environment around the part during the deposition process and during cooldown. These include Preheat Temperature and gas and powder boundary conditions.
Enter boundary conditions applied on the specified surface of the base, usually the underside surface, during the build and during cooldown. The wizard automatically selects the underside surface of the base by default.

Action buttons are described in the following table.

Action Button	Function	Action Button	Function
Apply Changes	Click to apply the actions for this wizard step, which updates the project tree. If you make changes, click Apply Changes again.	Help	Click to bring up help for this wizard step.
Read from Tree	Click to read the status of objects in the project tree and update the wizard input fields accordingly. Think of this as the opposite action of Apply Changes, which updates the objects in the project tree with inputs from the wizard.	Next	Click to move to the next wizard step. All required inputs on this step must be filled in to be able to move to the next step. If the button does not appear blue, not all required inputs are filled in. No actions are performed when you click Next. At times, you may want to fill out all the wizard inputs completely before applying any actions. Clicking Next without first clicking Apply Changes allows you to do that.
Advanced Options	Click to toggle on/off options related to gas and powder convection.	Back	Click to go back to the previous wizard step.
Advanced Options		Exit Wizard	Click to exit the wizard. Any actions you have performed using Apply Changes will be maintained in the project tree. No additional actions will be performed upon exit.

Input fields are described in the following table.

Input Fields	Description
Calibration Settings	Enter Thermal Strain Scaling Factor. This is an optional input that scales the thermal strains in the structural portion of a Thermal-Structural simulation by a given value. It is usually determined from calibration experiments to account for differences in materials, machines, and other factors. Affects these tree objects: Build Settings
Machine Settings	Enter the Machine Settings, which are settings and process parameters that directly influence how the process deposits material. Heating Method is the simulation assumption related to how the material is heated for each new layer as it is added (made alive). Choose either Melting Temperature (default) or Power. For Power, additional inputs are required: Heating Duration is the amount of time the heat is applied, either Scan Time (default) or Flash. Scan Time means that heat is applied for the amount of time it takes to scan the volume of material in each element layer. This setting may give better temperature results at the end of the layer but may not yield a temperature spike above melting. Note that this Scan Time option will have a different end time of the simulation because the layer thickness adjustment for cooling will not be used. Flash means that heat is applied in a very short time increment resulting in a spike in temperature then cooling before the next element layer is added. Beam Power is the power of the laser. Absorptivity is a fraction that describes how much energy is absorbed by the material and contributes to the heating process. Value must be between 0 and 1. Hatch Spacing is the average distance between adjacent scan vectors when rastering back and forth with the laser. Hatch spacing should allow for a slight overlap of scan vector tracks such that some of the material re-melts to ensure full coverage of solid material. Deposition Thickness is the thickness of deposited material in every pass of the recoater blade. Specifically, use the amount the base plate drops between layers. Scan Speed is the average speed at which the laser spot moves across the powder bed along a scan vector to melt material, excluding jump speeds and ramp up and down speeds. Dwell Time is the span of time from the end of the laser scan of one layer to the start of the laser scan of the next layer. It includes the time required for recoater-blade repositioning and powder-layer spreading as well as deposition of other parts that may be part of the build but are not being simulated. Dwell Time Multiplier multiplies the scan time by the specified number to represent identical parts built at the same time, but not present in the simulation. If they are the same part arranged in the same orientation on the build plate, the multiplier is the number of parts. In the case of symmetry, the Dwell Time Multiplier is required to reconcile the reduced time to simulate the build and should be equal to the number of repetitions (or sectors). For example, the build time for a half symmetry model is ½ of the build time of the full model, so the Dwell Time Multiple should be 2. Similarly, for a quarter symmetry model, enter 4 for Dwell Time Multiplier, and so on. Number of Heat Sources is the number of lasers if using multiple-beam printers. This divides the amount of time it takes to scan a layer by the number of heat sources specified. Affects these tree objects: Build Settings
Build Conditions	Enter Build Conditions, which are settings pertaining to the environment around the part during the deposition process. In LPBF, heat loss to the powder is simulated as a convection boundary condition unless it is explicitly modeled as a body (see Advanced Options in the Model Setup step). By default, these conditions will be added as thermal boundary conditions with the default values for temperature and convection coefficients set by the wizard. Convection coefficients default to 10 W/(m)²(°C). Use Advanced Options to customize build conditions. Preheat Temperature is the starting temperature of the build plate. Affects these tree objects: Build Settings
Base Thermal Boundary Conditions	Select the face of the base where preheat temperature should be applied, usually the underside of the base. Then click Apply. Use Ctrl-click to select multiple faces. By default, the underside surface of the base is already selected. Affects these tree objects: Thermal boundary conditions and loads under Transient Thermal system
Base Structural Boundary Conditions	Select the face of the base where the fixed support should be applied, usually the underside of the base. Then click Apply. Use Ctrl-click to select multiple faces. By default, the underside surface of the base is already selected. Affects these tree objects: Fixed boundary condition under Static Structural system
Advanced Options
Build Conditions	Enter details about the Build Conditions, which are settings pertaining to the environment around the part during the deposition process. In LPBF, heat loss to the powder is simulated as a convection boundary condition unless it is explicitly modeled as a body. Convection coefficients default to 10 W/(m)²(°C). Preheat Temperature is the starting temperature of the build plate. Gas/Powder Temperature setting allows you to use either Preheat Temperature or user-specified. Gas Temperature is the temperature in the chamber during the build. Powder Temperature is the temperature of the powder surrounding the part. Gas Convection Coefficient is the convection coefficient from the part to the enclosure gas. The convection is applied only to the top of a newly laid layer. Powder Convection Coefficient is the effective convection coefficient from the sides of the part to the powder bed. To estimate, divide the conduction property of the powder by a characteristic conduction length into the powder (for example, a quarter of the distance from the part boundary to the build-chamber wall). Powder Property Factor is a knockdown factor used to estimate the powder properties. The Mechanical application applies the factor to the solid material properties to estimate the properties of the material in its powder state. The powder-state properties are used in the newly added layer during the heating of the new layer (before its subsequent solidification and cooldown) prior to the next layer being applied. The default value is 0.01. This powder knockdown factor is also used if powder is explicitly modeled in the build. Affects these tree objects: Thermal boundary conditions and loads under Transient Thermal system
Cooldown Conditions	Enter details about Cooldown Conditions, which are settings pertaining to the environment in the build chamber around the part in the cooldown step after the build is completed. Room Temperature is the ambient room temperature. Gas/Powder Temperature setting allows you to use either Room Temperature or user-specified. Gas Temperature is the temperature in the chamber during the cooldown. Powder Temperature is the temperature of the powder during the cooldown. Gas Convection Coefficient: Same definition as in build conditions. Powder Convection Coefficient: Same definition as in build conditions. Affects these tree objects: Thermal boundary conditions and loads under Transient Thermal system
Base Thermal Boundary Conditions	Enter details about the thermal boundary conditions applied on the specified surface of the base, usually the underside surface, during the build and during cooldown. Boundary condition options include temperature, convection, or an adiabatic condition (no heat transfer). Base Face Selection: Select the face of the base where preheat temperature should be applied, usually the underside of the base. Then click Apply. Use Ctrl-click to select multiple faces. By default, the underside surface of the base is already selected. Build Condition is the boundary condition applied to the selected surface during the build, either Temperature, Convection, or Adiabatic (no heat transfer). Build Boundary Temperature (default): Temperature applied on the specified surface of the base during the build. Build Convection Temperature: Temperature for convection applied on the specified surface of the base during the build. Build Convection Coefficient: Convection coefficient representing heat loss through the bottom of the base to the machine during the build. Cooldown Condition is the boundary condition applied to the selected surface during the cooldown, either Temperature, Convection, or Adiabatic (no heat transfer): Cooldown Boundary Temperature: Temperature applied on the specified surface of the base during the cooldown. Cooldown Convection Temperature (default): Temperature for convection applied on the specified surface of the base during the cooldown. Cooldown Convection Coefficient (default): Convection coefficient representing heat loss through the bottom of the base to the machine during the cooldown. Affects these tree objects: Thermal boundary conditions and loads under Transient Thermal system