Thanks, works perfectly for me - every component is on its own layer and CNC machine can read layers automatically for toolpaths.

I'm trying to use -Sketchup to DXF and STL convertor plugin- but it takes layer names from -Entity name-. What I need is it to create layer names from definition name (the same name you give to component at first).

I found that this part of code is related but dont know how to change it:
#Componentinstance entity
elsif( entity.typename == "ComponentInstance")
if entity.name==""
entity.name="COMPONENT"+$component_count.to_s
$component_count+=1
end

After some change I now have the code like that:
#Componentinstance entity
elsif( entity.typename == "ComponentInstance")
if entity.name==""
entity.name="LAYER NAME"
end

Can anybody tell how to change it and use definition name? Plugin can be found http://www.guitar-list.com/download-software/stl-dxf-converter