HELP! Warping on Large Parts!

[SnoShadow 0]

So, last Friday evening I started a 36 hour print. It's a fairly large part, being approximately 6" x 8" x 1/2". I checked after the first two layers had been printed, and everything seemed to be working fine. I must mention that that was the 4th attempt at starting the part. The first attempt, I applied the glue that came with the printer, evenly across the entire glass building plate, and the result was that the brim didn't seem to be sticking very well, and especially toward the back of the machine, where the filament feeder tube has the tightest bend to it. It appeared as if the filament would partially stick to the build plate, continue through it's arc and stick again, thus leaving a straight line of material between the two points where it had stuck.

What I ended up doing on the 4th attempt was increasing the build plate temperature to 70 deg. C, turning the temperature of the material to 215 deg. C, material flow rate up to 110%. My reasoning being that by increasing the temperatures and flow rates that it would print larger 'beads' with each pass, then melt more onto the build plate, thus allowing it to stick to the build plate a little better. I should also note, that I did not use glue on the build plate on this attempt.

Material: PLA

Print Speed: 110% of the default 60 m/s, so 66 m/s

Material Temp: 215 deg. C

Build Plate Temp: 70 deg. C

Here is what the part should look like:

And here is the disaster that commenced:

Any help is much appreciated!

[neotko 1,417]

I think this post might cover all the issues you have atm

https://ultimaker.com/en/community/21245-is-bed-adhesion-really-that-much-of-a-problem?page=last#reply-147975

[Yoter 14]

It sounds like your bed may be out of level if you're consistently not sticking at the back.

When I re-level my bed, I follow Ultimaker's instructions with the business card to get me in the rough area. Next, I start a print that is about 8" x 8" with a four line skirt, and run it very slow, like 20mm/s. I watch my first layer. I like it pretty firmly pressed into the glass. Some people like it smashed hard, I learned that's a little too much. While the skirt is printing, I adjust my three level screws until I see that first layer where I want it. Next, I cancel the print and start it again to make sure it ended up consistent and how I like. Then I cancel the print and get printing whatever I want.

With a well leveled bed and good first layer, print adhesion should never be an issue short of getting oil or contaminants on the build plate. I can't remember the last time I printed a birds nest right off the glass. Also, are you setting a lower first layer speed? I know Cura slows it down automatically, I like to lay that first layer down just as slow as I can tolerate.

[element7721 3]

I've used hair spray in the past.  In most of my prints, it actually did too good of a job holding the prints down, and it ended up being really hard to get them off the bed!  So if you want more stick in the future, that can be a good option.

As you would expect, it is flammable though, so make sure you take care when applying it

[korneel 176]

which glue stick are you using? there are good and bad ones.. i like the TESA ECO STICK.. works awesoeme for me..

take the glassplate out, clean it thouroughly.. then apply a thin layer of glue stick. take a towel, make it wet, dan gently smear theglue over the glass plate, so there is a super thin layer (not visible even).. that should work awesome.

[yellowshark 153]

Bear in mind that when your bed temp reaches 60 or whatever temp you set, that will probably be the centre of the bed and there of the bed will probably be at least 10 degrees cooler. The positioning of this probably differs between various makes of printer.

For a print covering most of the bed you need to wait for the outer areas to reach the temp. Not sure why you decided to leave the glue off, that can only make it more difficult to stick.

[LePaul 316]

Oh I feel your pain, I've made PLA-spaghetti a few times too.

As others said, glue stick helps a lot.

I'd be curious how you had it oriented to print, like a screen shot from Cura. Is there a lot of support material holding the base?

Give the glass a thorough cleaning. Remove all contaminants, even if you don't think there are any. I scrubbed my clean in the sink with dish soap, allowed to completely dry, then a once over with glass cleaner (windex).

I heat the bed to 60C manually then do a few swipes with the glue stick. I go quickly so you don't get those "chunks" on the bed