Overhang Print Problem

Hi All

I am having a funny problem with my Prusa i3 printer lately, whenever I print any sort of overhang (45% or less) the filament seems to droop and creates a very untidy print.The top of the print is printing perfectly. Any suggestions as to what this could be? I used to print these items quite easily.

My print settings are as follows:

Nozzle Diameter: 0.40 mm
Layer Height: 0.2 mm
Extruder Temp: 190
Bed Temp: 60
Print Material: PLA
Slicer: Simplify3D

This is what it looks like:


Thanks

What's the extrusion width? It needs to be wide enough so that some of the perimeter is on top of the layer beneath or it may droop.

Do you have a cooling fan pointed at the PLA? This will help with droop.

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What's the extrusion width? It needs to be wide enough so that some of the perimeter is on top of the layer beneath or it may droop.

Do you have a cooling fan pointed at the PLA? This will help with droop.

My extrusion width was was set to 0.48 mm (From what I read this should give a good quality print?). I do not currently have a fan setup for my printer as I still need to get a fan duct printed. I will give it a try with a normal desktop fan to see if it makes a difference. I have also tried the same object in Slic3r (Similar settings) and had very similar results.

0.48mm is a little on the low side, with 0.2mm layers and overhangs.

As an example, if you have a 45 degree overhang, the perimeter will draft outward ~0.3mm for every 0.2mm the print gets taller, so less than half of perimeter width will be in contact with the previous layer.

You can still keep 0.5mm as perimeter width, you just have to go a bit lower on the height.

Edited 1 time(s). Last edit at 10/18/2014 04:11AM by Ralf.