SolidWorks supports STL CAD files for 3D printers, so should offer users all the tools needed to successfully convert sldprt to stl, i.e. export part design made using SolidWorks to STL format for 3D printing.
However, most users that are looking for sldprt to stl conversion actually do not have access to SolidWorks, in which case the situation is a little more tricky. Plenty of programs nowadays support SolidWorks formats, yet most of them are commercial and not available for free. Although some online sldprt to stl converter options exist, the results might not be perfect.
Open SLDPRT file Open STL fileA set of 3D modeling tools
An online CAD conversion service
A CAD converter with huge format support
A CAD visualizaton, analyzation and translating system
A commercial online CAD converter
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A dedicated CAD converter