Top Layer Bubbling

[officebitch 0]

Hello Friends,

I keep running into the problem of the last layer above the my infill will bubble/warp/look like crap.

I was wondering if anyone has had this problem and found a good solution.

 

 

Of all the forums I've read it seems that there is a "sweet spot" combo of temperature and fill speed, but I cant find it.

 

Thanks Everyone

 

 

[illuminarti 18]

Make sure that the fan is on, and is blowing air on the print, not sucking. That makes a huge difference. Then try move layers of solid (i.e., a thicker top/bottom thickness, as a multiple of layer height) - generally 5-10 depending on layer thickness you are using, and/or printing with denser infill, so that the gaps to be bridged are smaller.

 

[gr5 2,170]

That pattern of "bubbling" is common over 20% infill if the fan is off.

But your print looks like every layer is solid. Which is it? Solid or not solid lower layers?

 

[ltc 1]

I think my prints have the similar issue.http://imageshack.us/photo/my-images/853/1xuy.jpg/ is the head part of a miniature, about 60 mm tall, printed with PLA at 0.1 mm layer thickness and 0% infill. The other http://imageshack.us/photo/my-images/822/fjb9.jpg/ is a figurine. Its face looks seamed with a big wrinkle. It is also printed with PLA at 0.06 mm layer thickness and 0% infill.

The fan of my Ultimaker always keeps turning on and the problem occasionally happens. I suppose it might caused by the extruder leaking.

 

[illuminarti 18]

That wrinkle looks like it is due to insufficient cooling time per layer. You need to allow at least 5seconds per layer, with the fan on full, and blowing the right way, for the plastic to cool before you start the next layer.

With smaller parts that print quickly this can be hard to achieve without printing incredibly slowly. In those cases, printing multiple parts at once might help as it gives the head something to do while the first part cools.

[3dcase 37]

Hi,

Looks a lot like my last print, printed it without fan, due to a technical problem, because I stuck a screwdriver in it while levelling the platform :shock:.

And indeed you need the ten layers of solid top infill to straighten the top.

I do not hope it has something to do with the neat strong square infill, you might not have this problem (or less) with cura 13.04, doing a more open infill.

Ever thought of soldering or welding a pressurized tube or steam pipe. :???:.

But I hope it's the fan or a too high temp.

 

[officebitch 0]

OfficeB again. We're using pla, all layers at .3mm. We thought maybe the bubbling was happening because the infill wasn't high enuf--the last layer not sticking to the layer beneath--so we pushed infill to 80% from 40%, and the problem got worse. Looked like the fan was blowing up the top layer, and sure enuf, turns out most of the bubbling is caused by the fan running at 100%. 1st we reduced the fan to 50%, which helped some, then to 20%, which helped a lot more. Then put infill back at 50%, and turned off the fan--manually--on the top layer, which got the best results. Anyone had similar problems with too much fan on the last layer, causing the bubbling shown in the pics above?

 

[gr5 2,170]

That's a bit bizarre. Usually less fan is needed when you have shrinkage issues. Maybe you had some shrinkage/warping because the part cooled down to fast. I'd love to see a photo of your fan and fan shroud. Are they pointing at the part or the nozzle tip? (ideally you want not very much wind on the nozzle).

 

[broffey 0]

I had a similar problem. Based on illuminarte's insight about cooling between layers I reduced the room temperature to 15C and reduced the print temp to 205C. This seems to have solved the problem. Thanks for the help guys!