Flat surface 6mm thick

[O_Tiby]

Hi all,

I am an owner of a Wanhao Duplicator 4. For a project I make a model with a flat horizontal surface of 6mm thick. I tried first a little piece of 50x50x6mm and this was the result:
WP_20141028_006.jpg
WP_20141028_007.jpg

The first image is the top, it has holes and isn't quite well. The second image is the bottom, which I think is perfect. How can I improve the top?

My setup:
Wanhao Duplicator 4
Black PLA
nozzle temp: 195 C
bed temp: 50 C
Shells: 3
infill: 15%
Speed: 60-80

Thanks for your responses in advance!
Oscar

[Marm]

I'm not the most knowledgeable here, but personally, I'd increase the infill to give the surface more support to rest upon. 25%-35% is about where I can expect a fairly flat, if not smooth surface.

[Geoff]

I'm not the most knowledgeable here, but personally, I'd increase the infill to give the surface more support to rest upon. 25%-35% is about where I can expect a fairly flat, if not smooth surface.

Looking at the picture, there is no infill - it looks like solid layers.

The print is slowing down on the last layer, that's why that happens. You need to set the last layer to print faster or a little further off the plate, its just that little bit too close for printing slow.

[Marm]

I didn't see that in the photos, but he listed infill at 15%. But it may not have reached the wall thickness to start infill....

[curious aardvark]

well if it's only 6mm thick and 50mm square 15% infill should be fine.

What layer thickness was it printed at ?