I am having trouble exporting meshes as .stl files from blender, when I import the exported mesh into Slic3r nothing shows up. However when I import an already existing model into blender and then export that as a .stl, it works fine in Slic3r
For me to get this to work. I changed units to metric. To create a 2cm cube I had to create a cube and set the scale to 2cm. I made sure that I applied the scale to the cube so that it says:
scale x: 1 scale y: 1 scale z: 1
length: 2cm width: 2cm height: 2cm
Then I exported selected as *.STL and dragged into Slic3r. From there I applied a scale of "100,000" as "100" was default. YES you heard that right 100k. I'm not sure why this happening but it works for me and I measured my model after i printed it and it's 2cm square. Hope this helped.