General discussion  - 
First impression of that Faberdashery 3mm PLA:
+ More accurate then my old one.
0 Warps just as badly.
- Comes without spool and silica.
Jason Gullickson's profile photoThantiK's profile photoMarcus Wolschon's profile photoargh c's profile photo
PLA?...WARP? -- do you not have a fan on it? (a strong one?)

I don't ever think I've had PLA warp.  Even the crappy stuff.  Only thing that warps on me, ever, is ABS - and largely it stops after a little ways up the print.

Seriously, with PLA...the stronger the fan, the better, as long as your system can keep up with it.
I tried a very strong fan at CCCongress and it made the warping much worse.

185-190°C instead of 2xx°C and turning the heated bed up usually helps.
What temperatures and speeds are you using?
Heated bed?

I don't see warping on small parts but a solid 100x100mm square is a problem. (Had do give up printing a 100x80mm case for a camera flash during CCCongress due to warping.)
185C for PLA, all sorts of kinds.  Got stuff from years ago, months ago, different suppliers, china, USA, all over the place.  Both heated (55c) bed and non-heated bed work for me, for PLA I always print on 3M blue painters tape (not the smooth kind, the textured kind) - I can't ever seem to get PLA to stick to straight glass for me any more.
190 works much better now. Visible but very low warping.
Will have to wait a few more layers to know for sure.
Hated cenveyor belt at 135°C, holds that temperature fine. Betwen 134 and 136°C. Titanium instead of the original plastic belt makes all the difference.

185°C ment the actual meassured temperature would drop as low as 180°C/181°C and the layers where too thin and didn't stick.
Yeah, if you're bouncing between 180/185 that's a huge problem too.  I don't go more than a 1 degree +/- because my software (marlin) has the PID tuning set up.
Also, PLA has a glass transition temp of around 60-65C, running the bed at 135C is way overkill, and likely to make your part sink/melt.
It keeps the temperature difference between top and bottom low and should thus reduce warping.
Would a lower bed temperature be better and why?

Currently printing at 5mm height. One edge has risen about 1-2mm but not more. Looks okay.

Had to give up the 200/120°C print at half this height.
Yeah that hot for a heatbed and PLA is causing your warping but thats not warping in the ABS sense is more or less melting. PLA needs to cool down soon after printing where ABS generally wants to stay warm.
I see.
I'll try a lower temperature and the fan next print.

Didn't know that it would expand at temperatures so low.
Everybody just talks about the temperature in the extruder, not that the bed can cause problems at all.

It's strange that the strong fan had a negtive effect at CCCongress. (We blew up a PC power supply and thus where left with a working fan that the power supply would no longer need.)

Thanks a lot!
55C for heated bed on blue painters tape (3M brand), or even no heated bed...and 185C extrusion temp is generally the recommended starting point.
My bed is an 0.025mm titanium belt covered in kapton tape.
Will experiment with the temperature to see if it still sticks.
But will stay below 65°C and try to hit 55°C.

Can't use blue painters tape on the conveyor belt as I can't exchange it for fresh tape.
I've had PLA warp badly, but only on large items.  The Shofar horn on Thingiverse was a bear - I had to print a solid raft with a 15mm brim to hold it down - WITH a heated bed.
I'm surprised you're still using the conveyor belt - As far as I'm aware, most ToM users replaced that piece of junk ages ago.
This conversation is very interesting to me :)

I get warping (maybe theres a better/more correct term?) using PLA on a cold glass bed covered with blue tape when I print larger parts, especially parts that are thin in the x/y dimensions.

Part of my problem is due to trouble getting the tram of the bed right (which I should be able to resolve soon, got a nice big piece of AL in the mail today :).  I think mine is essentially an adhesion problem because the nozzle is too far away from the build surface at some points but I'm not sure fixing this will solve all my warping problems.

...I'll let you know how it turns out :)
+Anthony Morris With a MBI plastic belt it's a piece of junk.
But disassembling it and replacing it with a good conveyor belt made out of titanium and with a tightening-mechanism it works like a charm.
I've been printing stuff like this in PLA, at nearly my bed extents: - 100mm high.  Strong fan, no heated bed, blue tape, all sorts of strange PLA from all over the problems. :)
Heating up to try 55°C, strong fan, 190°C now at 64mm/s....
+Marcus Wolschon yeah, with kapton, you'll need to be heated (55C is fine).  PLA doesn't really like sticking to kapton without it.
I'm waiting for a Makibox HT. Will try blue painters tape on that one. (Before I convert it to a conveyor belt too. ;) )
With 55 at the bed, the thin belt above it is only slightly above body temperture due to the strong fan. Trying 65°C...

65°C bed =>32°C belt
76°C bed =>36°C away from th fan, 32°C in the fan, nothing sticks

now 55 and blocking the fan...
The biggest thing is that your PLA gets cooled off quickly.  Even if it's a light breeze, if you can keep 55c at the bed, and get the PLA cooled down before the extruder comes back around, you should be good.  You may end up needing some sort of small fan shroud that directs cool air to the freshly printed PLA, but nowhere else.
I disabled the fan and am trying 55 without fan,
Will look for a smaller fan next week.
Yeah, my strong fan recommendation was without the realization of how weak your heater is.  I'm so used to my crazy overpowered bed heater I didn't take into account that not everyone has that setup. -- completely my fault. :(
Heating for 75°C with no fan gives me an actutal belt-temperature (infrared) of 40-45°C rising to 52°C in the center during the first layer. PLA sticks.
Trying to print...

One edge is rolling up slightly. May be due to poor adhesion instead of real warping.
There is too much insulatiion between bed and belt. The actual belt is hardly getting above 45°C on average. Will go with bed=100°C to see if that is a good compromise to fix first layer adhesion.

then stabilizing at 54-57°C. Looks okay.
I guess I've found my settings. Nearly no warping despite nearly all of the build surface filled with 3 solid layers of plastic.
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