What is a sldprt file? can it be converted to a .stl file?

sldprt is a Solidwork (CAD Designing Software) file extension means if u save solidwork file in your computer it will be saved as "filename.sldprt" format.
Yes, u can convert sldprt file into .stl format by using solidwork software by selecting save as and select stl format to save.

I hope this will help.

Is a SOLIDWORKS Part File, and yes , can be converted into a STL File, i'm Solidworks user if you want send me the file and i do the file conversion.

Hi, This is a good question many people who works on the 3D printing industry face.

Firstly,
The .sldprt file is the standard of the origin file created using the software called SOLIDWORKS, which is an advanced CAD-CAE software.

A SOLIDWORKS user could straightaway save the .sldprt as a .STL file, where as following the procedure of;

File>>Save as>> (select .STL) as shown on the Image.

Apart from that, there are many third party converters, which could be used in converting .sldprt files to .STL file.

If not you could try GrabCAD Print for it. https://grabcad.com/print?locale=en