Could someone tell me the simple thing I'm doing wrong with this PLA print?

So as you can see everything prints beautilfully up until past the base. It's PLA. The extruder is run at 180. The bed is at 75. It was made in Slic3r. Do I need a fan or something to fix this?

Thanks

This just looks like the layers aren’t solid enough when the next layer are added. Have you tried printing a simple 10x10x50 calibration shape? Early on I was having some similar problems. A fan helped a bit but what really solved it was using the “cool” option in skeinforge. This option had the printer adjust print speed based on layer time to prevent going too fast on small layers. I’m fairly certain slic3r has it to. I fiddled with this until I could print a 1.5mm cylinder to 50mm tall.

I tried a few of those cooling options. The print quality got better but the filmanet was extruding so slow that the extruder jammed, I guess it's a PLA thing. I'm going to have to do some experimentation with that

thanks

i was printing at 180C all the way up before.. but then i found that the previous layers was too soft to form a good base for the new layer so now i print first layer at 170C and the rest at 160C and so far it has worked pretty well for me even without a fan.

there's an option in slic3r 0.7.1 that allows u to set first layer temperature different than the rest. u can give that a try.

All of my prints are in PLA and I’ve never had the extruder jam from print speed. What hot end are you using? Have you tried adjusting the temperature (I typically do slightly warmer then you)? Have you considered increasing the current to your extruder stepper?

Zarquon Wrote:
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> All of my prints are in PLA and I’ve never had
> the extruder jam from print speed. What hot end
> are you using? Have you tried adjusting the
> temperature (I typically do slightly warmer then
> you)? Have you considered increasing the current
> to your extruder stepper?

Buddaschnozzle 1.1 from Lulzbot. I'm starting to think Lulzbot hasn't done a whole lot of testing with PLA. The temperature change in midprint sounds like a good idea but I'd need it to change only on the layers that are having the problem. I don't think adding more torque to the extruder would help. When the extruder jams it seems to be because the filament is deformed at which point the hobbed bolt just starts grinding filament.

These are all good ideas though, thanks

> Buddaschnozzle 1.1 from Lulzbot. I'm starting to think Lulzbot hasn't done a whole lot of testing with PLA.

We run 2 (or more) PLA printers business days 7am to 3pm for about 6 months now.

Judging from your first photo, the problem is that it is too hot doing the "towers" you have there. That is why slic3r has the "Cooling" tab. If you print one small part where the nozzle basically never leaves a spot for very long, the layer doesn't cool enough before the next layer is put down. This is true regardless of which hot end you are using. To get around this there are at least three things you can do to prevent it: 1) use "cooling" in Slic3r. 2) Add a fan to cool the extruded plastic (not the hot end itself). 3) print multiple copies of the same thing all in one plate. That way the printer does the first layer of one copy, then goes to the 2nd, 3rd, etc. and the first one gets time to cool in the interim.

I don't recall a budaschnozzle clogging with PLA. Different types of PLA require different temperatures, so it may be related to that.

jebba Wrote:
-------------------------------------------------------
> > Buddaschnozzle 1.1 from Lulzbot. I'm starting to
> think Lulzbot hasn't done a whole lot of testing
> with PLA.
>
> We run 2 (or more) PLA printers business days 7am
> to 3pm for about 6 months now.


Hmm... it might have to do with the fact that I built a wooden enclosure around it. Maybe it's causing too much heat to build up in the extruder assembly. The budaschnozzle doesn't actually clog. Excess heat in the extruder assembly causes the pla filament that's in their to deform to the point when it gets kinked between the bottom of the gear housing and the top of the abs plate where the hot end is mounted. I think I might add a couple of fans, one for the print and one for the extruder.

crutonius Wrote:
-------------------------------------------------------
> Hmm... it might have to do with the fact that I
> built a wooden enclosure around it. Maybe it's
> causing too much heat to build up in the extruder
> assembly. The budaschnozzle doesn't actually
> clog. Excess heat in the extruder assembly causes
> the pla filament that's in their to deform to the
> point when it gets kinked between the bottom of
> the gear housing and the top of the abs plate
> where the hot end is mounted. I think I might add
> a couple of fans, one for the print and one for
> the extruder.

For printing PLA it's almost a requirement to have a fan blowing over the thermal break in the hot-end, especially if you are in a warm environment.

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