Top part of a print always melts and deforms

Hi all,

I have been struggling with printing small parts for a long time.
It seems that the nozzle melts the layers that have already been printed which eventually leads to a catastrophic failure.

I use a prusa i3 rework and I don't have a fan to cool my print but it seems that most people can print "less challenging" objects very well without one.

Attached is a photo of the my prints of the "5mm calibration cube".
As shown in the photo, the bases were of acceptable quality but the top parts basically melt and collapsed under their own weight.

Here are some basic settings:

Nozzle = 0.5mm
Slicing engine: Slic3r (tried Cura but it didn't work neither)
Print layer = 0.3mm
Filament: PLA 1.75mm
Print temp: 180C
Print speed: ~40mm/s
Retraction: 4mm@60mm/s
Z-lift: disabled

Shall be very grateful if anyone could give me some pointers.

Thanks in advance,
MonkeyHead

you need to use fan for coling and slow down print in small areas or print more object same time

Edited 1 time(s). Last edit at 06/10/2014 01:21PM by premek.

As premek said ... You have a option in Slic3r. Under "Filament Settings", cooling. You need a fan and slow down the print or print multiple things at the same time

Edited 1 time(s). Last edit at 06/10/2014 01:45PM by ncq.