How to set the fan speed for 0.06mm layer prints?

[weiin 0]

I've been trying to print at 0.06mm layers but I'm getting problems with the fan side of the print. At 0.06mm, the layers tend to "dry out" quite quickly on the fan side, causing scars on that side. See some pictures of my most recent print here:

 

I've tried turning off the fan, but as expected, the layers won't dry and gets all mushed up. For the latest print, I've set the fan to 60% max speed, printing at 220C 70mm/s. I've tried "high quality" setting in Cura 13.06, but the drying out is similar or worse.

 

I'm using a pretty stock setup, with the fan duct changed to the printed one by Daid. Anyone has any idea how to solve this? Os should this be expected for 0.06mm prints?

 

[illuminarti 18]

I'm not convinced that this is a fan problem. I think it's more to do with the model geometry. I've printed several things lately with 0.06mm layer heights with absolutely perfect results all around.

What wall thickness and infill settings are you using, and what speed are you printing at?

 

[gr5 2,004]

That "wind scar" looks like infill showing through. Did you have infill turned on? Hopefully you haven't re-sliced yet and you can go to the gcode view in cura and see if where the infill touches the edge matches the "scar".

You can probably fix this by setting your wall thickness thicker. So if you are at .4 go to .8. If at .8 go to 1.2. The latest Cura has a bug (a feature?, an issue?) where the infill can stick out through the wall. I have another post showing what's different in the new infill:

http://umforum.ultimaker.com/index.php?/topic/2501-is-this-slicing-settings-or-hardware-problem/?p=17683

That post was a week ago when Daid wasn't posting much so he might not have read it.

 

[weiin 0]

I have seen the infill protrusion issue, but I'm not referring to that. I have uploaded another two pictures of the um robot printed using the "high quality" setting: http://umforum.ultimaker.com/index.php?/gallery/image/868-um-robot-fan-sidebrightened/ and

http://umforum.ultimaker.com/index.php?/gallery/image/869-um-robot-non-fan-sidebrightened/

I've brightened the images to hopefully show how the colors are not uniform on the fan-side. Some layers appear "whiter" and "dry-er". On the non-fan-side, the print is much more uniform in color.

Also, if you look at the http://umforum.ultimaker.com/index.php?/gallery/image/867-head-top2/ print, you can see bands where the infill touched the perimeter. However, the non-fan-side of this print (right of picture) has a uniform blue, whereas the fan-side (left of picture) has a visible whitened surface.

The layers curling on the underside of the chin in http://umforum.ultimaker.com/index.php?/gallery/image/864-head-fan-side/ (the piece on the right) as compared to the smooth "face" in

http://umforum.ultimaker.com/index.php?/gallery/image/865-head-front/ also show the effect of the fan.

 

[gr5 2,004]

First of all, why post .2 megapixel pictures. Can't you upload higher res images? It's hard to see in these. I looked at them for a good long time the first time and don't see anything new this second time. Well except that the antennas on your UM robot are printed much too hot - they need more cooling - usually you can increase the "minimum layer time" in the "cool" section to at least 7 seconds to fix this. And make sure the fan is on. You get melty, droopy layers when you don't let a layer cool enough before the next layer goes down.

.06 thick layers is nice and thin and if you are going to print at a leisurely 70mm/sec (I would try 200) then you might as well lower the temperature to around 190C. That might help those antenna on the robot and other droopiness.

Anyway - to your issue...

I guess I've never paid attention to the color of the plastic. I guess it hasn't been an issue for me. I will pay more attention in the future.

It seems hard to believe this is related to the fan as while you are printing, the fan blows more on the top of the print than any particular side. Sure 10 layers later, the fan blows briefly on the "fan side" but not the other 3 sides. But it's hard to believe the color is changing many minutes after the layers have been laid down.

It really looks more like an issue with infill. When the head comes over to do infill it touches the outer edge and reheats it. Of course this should happen on all edges, not just the left side.

Maybe the fan is blowing on the nozzle? (it shouldn't be) That might cause one side of the nozzle to be cooler? Arrg - this seems unlikely to me. I mean across the 2mm area of the tip of the nozzle it should be all about the same temp no matter how hard the fan is blowing on the nozzle.

Anyway, hopefully someone else will look at these (tiny) pictures and recognize this issue. I certainly don't.