Check In Assembly as Part (SOLIDWORKS)
You can check in an assembly (*.SLDASM or *.ASM) as a part (*.SLDPRT) to Windchill using the Check In Assembly as Part action.
From the SOLIDWORKS ribbon bar, click > 
Check In Assembly As Part to access the action.
Check In Assembly As Part to access the action.Check In Assembly as Part allows you to create a new part even if the assembly is locked or opened in the Lightweight mode.
Checking in an assembly as a part creates a source and image relationship between the assembly and the newly created part in Windchill.
New Part File Naming Rules
When you use Check In Assembly as Part, Windchill automatically generates a file name for the new part.
• SOLIDWORKS assembly: The file name of the new part is the assembly file name followed by _SLDASM.SLDPRT.
For example, for an assembly named CylinderBlock.SLDASM, the new part file name is CylinderBlock_SLDASM.SLDPRT.
• SOLIDWORKS assembly with family table instances and active unmanaged configuration: The new part file name includes only the generic name.
For example, if the generic name in an assembly is Retainer.SLDASM and its active unmanaged configuration name is FT_Config3, the new part file name is: FT_Retainer_SLDASM.SLDPRT.
• SOLIDWORKS assembly with family table instances and active managed configuration: The new part file name includes the managed configuration name along with the generic name.
For example, if the generic name in an assembly is Retainer.SLDASM and its active managed configuration name is FT_Config3, the new part file name is: FT_Config3_FT_Retainer_SLDASM.SLDPRT.
Limitations of Using the Check In Assembly as Part Action:
• The Check In Assembly as Part action applies only to assemblies that are unmodified and checked in to Windchill.
• Even when the assembly is unmodified, you must not check in that assembly as a part if its child components are modified.
• Any unsupported characters in the file name of the assembly configuration are replaced with an underscore (_).
• Even when the preference Include generic name with instance is set to Yes, the @ symbol is replaced with an underscore (_).