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.SLDASM File Extension

File Type	SolidWorks Assembly File
File Format	File
Common?	No
File Description	Three-dimensional assembly created with SolidWorks CAD software; typically contains several SolidWorks Part (.SLDPRT) files organized into a single assembly.
Program(s) that open sldasm files	Windows: Solid Concepts SolidWorks or SolidWorks Viewer; Adobe Acrobat 3D

Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/sldasm