The plugin for Inkscape on Windows can be downloaded here.
Some versions of Windows doesn't allow the plugin to be installed properly due to administration rights when adding files into other softwares. Please download the attached file to this post and extract it and then copy the two plugin files and add it under
32-bit: C:\Program Files (x86)\Inkscape\share\extensions
64-bit: C:\Program Files \Inkscape\share\extensions
You will then find Send to SignCut under export in the Extension menu in Inkscape.