Can't make an Anet A8 successfully print wide features

[blue68]

Hello everyone,

I own an ANET A8 and have great trouble solving a problem when printing wide features.
I print with default CURA 3.6.0 profile “Normal” with print speed reduced to 30mm/s.
My filament is SunLu PLA+ and print them at 220°C (When printing at 200°C I had under-extrusion problems) with retraction of 6,50 mm at 25mm/s.

Small object are printed pretty well: (can’t upload the image )

When I print big objects, it looks like:

And layers are not sticking to each other: (can’t upload the image )

I tried to print the test boat. It starts well and then at a certain height it gets bad:
(can’t upload the image )

After many attempts to solve the problem, I am running out of idea. Has someone any clue?

PS: the printing was fine before I made some changes:

• Used another filament brand (former one was Ice PLA)
• Added autoleveling probe (BLTouch)
• Changed printing bed surface (from glass to buildtak)
• Updated to MarlinFw - bugfix 1.X (from ANET FW)
• Enclosed the printer in a Plexiglass box.

[blue68]

Here are the missing pictures: