Gaps between outer and inner layers

[Dubs_only 0]

I am having a problem printing some of the files I've made. The models are very small (1:220) but the problem that I'm having is a gap between the outer and inner walls as you can see in the picture. I am using the newest version of cura and I have it set to .1 mm I have mainly the default settings the only thing I have changed is the printing speeds for the top and bottom layer I changed it to 15 millimeters per second this seems to be the main problem that I'm having printing my very small models hopefully the fix is simple I'd appreciate any help let me know if you need any more information.

[Dubs_only 0]

Here's my shell and quality settings. 

[gr5 2,172]

This is basic underextrusion.  There are many possible causes.  Is this a UM2?  Is this printer no longer brand new?  If "yes" to both questions then I'd guess it's the teflon part in the printer.  You need to replace that about every 500 hours or so.  More often if you print hotter than 220C.

 

I can give you a complete list of possible causes of underextrusion if you tell me what printer it is.