I have a sketch that I plan to export to .dxf or .dwg to be used for laser cutting. However, in order to work properly, I need to convert the many lines that make up my model into a single line for cutting purposes. I have tried DraftSight and converted each line into a polyline and joined them together but that has delivered some weird results where only some lines would join together and others were still seperate..I am wondering and/or looking for any input on what the best way to solve this would be..

I have attached a .dwg file of a test model that I created in SolidWorks and attempted to edit in DraftSight to create a single polyline of the border..