Small part bed adhesion I am trying to print a model that has (at the start of the print) several small parts attached to the bed. Some of these parts have bed contact 2.5mm x 20mm.

After a few layers, if there are any imperfections in the previous layer, the hotend is bumping the imperfection and knocking the part loose.

I am using a genuine Prusa i3 Mk2s with Filaform PLA. I am slicing with PrusaControl and using the "Generic PLA" settings, which is giving me 215/210 degree hot end (first/other layers), and 55 degree bed. I have the fan enabled. The print bed is clean and dust free

How can I improve bed adhesion for these small parts, ideally without adding brims etc? 

Thanks
One technique is to add your own custom brims to the model. A couple of "Mickey Mouse ears", attached to each end of the piece, may be enough to keep it in place (and will also be easy to remove).