Unkown issue between the filament tube and printcore

[eKoh 0]

I was printing in ABS and I got the following issue:
 

s

 

This made the printer unable to retract and also unable to print.

 

---

 

This just happened after I reduced my Fan speed from 80% to 25% (this due to I am printing in ABS, and as it cools down quickly it also shrinks), I made several tests on a Build Plate Adhesion Torture Test, and I finally got that:
Regular fan speed: 25%

Maximum fan speed: 50%

Had the best results. Never faced this issue before

 

How can I solve this issue without changing the fan speed?

[values]
bottom_layers = 3
cool_fan_full_layer = 3
cool_fan_speed = 50
cool_fan_speed_max = 80
cool_fan_speed_min = 40
cool_lift_head = True
cool_min_layer_time = 15
infill_pattern = lines
infill_sparse_density = 10
retract_at_layer_change = True
roofing_layer_count = 1
skirt_line_count = 2
top_layers = 2
travel_compensate_overlapping_walls_enabled = False
wall_line_count = 2How can I solve it without increasing fan speed?

Here are my specs:
Ultimaker 2+
Nozzle = 0.8mm
Bed temp = 80ºC (I tried from 80 to 105 and 80ºC had the best results)

Print temp = 260ºC (From 230 to 260ºC the last one had the best results)

 

[values]
bottom_layers = 3
cool_fan_full_layer = 3
cool_fan_speed = 25
cool_fan_speed_max = 50
cool_fan_speed_min = 20
cool_lift_head = True
cool_min_layer_time = 15
infill_pattern = lines
infill_sparse_density = 10
retract_at_layer_change = True
roofing_layer_count = 1
skirt_line_count = 2
top_layers = 2
travel_compensate_overlapping_walls_enabled = True
wall_line_count = 2

Edited March 7, 2018 by eKoh

[gr5 2,230]

Three things.  It's probably one of these 3 things.

 

Make sure your third fan is working - the one on the back of the print head.

 

Check your retraction distance on your printer.  It should be 4.5mm.  If it's more than this you can get the issue you showed.

 

When inserting your bowden - it's very common for it not to go all the way into the white teflon part.  From the photo I can see you have a solid aluminium spacer above the white teflon so it's hard to see what's going on so you have to do it by feel.  The older printers have a spring instead of that metal spacer so you can see what's going on.  Also make sure the bottom of the bowden is cut "square".  Meaning perpendicular.  It's okay to cut 2mm off the end of your bowden twice to get it square.