No extrusion in the middle of print

Hi all,

I've been trying the print this using slic3r RC 3,0.35 nozzle at normal speed (60).It all started very good but in the middle this comes out.Nozzle is clean,filament goes trough nozzle with hand, i have a fan cooling upper part of barrel,and another one cooling the print when needed,i'm using arcol v4 hotend ..any thoughts on what might be the issue here?first 5 layers were great

What filamet and temp are you printing at?
You might try to increase the temp a bit. Or you may be off on the z calibration and your head is dragging through the print causing the jam. You could try a higher layer height to ssee if it jams.

Using white formfutura filament,and printing @200C,i checked z calibration and it seems fine.Due to 0.35 nozzle i read someware that the best results are with up to 80% of the nozzle diameter for layer hight.

Now im printing @ 205C and i reduced the number of polygons in the model ,we'll se how it goes in the middle

I noticed one thing and that could be the problem. I have two fans blowing,one all the time cooling upper part of hotend ,other is switched on when slic3r sends a command(auto fan on).The thing is when the second one goes on,temperature drops rapidly well below 205C,someware around 187C causing lausy extrusion.Why is that?and what does "T:205 @: 120" mean? (@120) part... now when i switch off this second fan printing is much better

Why is a fan blowing on your hotend causing the temp to drop? .. the better question is why doesn't your hotend stay at temp with a fan on it. Reason is your heating eliment cant keep up with air blowing on it. You can try to put some kind of duct on your fan to keep it off the hotend, or insulate the hotend with ceramic insulation.