Prints pulling up at corners

[naturalstate720]

Hi,
I'm new to 3d printing and am doing my best to get acquainted with everything, but am getting a little frustrated. We bought the makergear m2 fully assembled. I'm printing w/ PLA and have tried a lot of different bed temperatures from 40-80 degrees. Our nozzle is 215. I've tried setting first layer 5 degrees hotter and then reducing.

We're mainly printing architectural models that have a large solid base, but 20-30 minutes into the print, the corners are always pulling up. It's usually the same corner that is always the worst. We've always printed directly on glass. We've tried the fructis hairspray that is recommended, elmers purple glue and bare glass. The skirt always sticks, the first layers always stick, but it's way later in the print that the corners come up. Is this a bed adhession issue? It also seems to be realted towards larger prints. When we print smaller objects they usually stick fine.

The other thing is that our desk is a little shakey. Could this be the problem?

I've looked at the zstop and bed leveling. The bed appears to be very level, I've used feeler gauges at .006 and it seems like there is adequate resistance. I changed the extrusion multiplier to .92 based on caliper readings. I've tried printing rafts, but they eventually pop off at corners too.

I've attached two photos showing the corner warping. I have since figured out how to add supports that were not in these.

Can anyone help? I feel very overwhelmed with conflicting information, and stuff spread out everywhere.

[Jules]

Is the corner that is always pulling up the one that is farthest away from the fan?

Having an extreme difference in temperature from the front of a tall model, and the back of it, is probably what is causing the PLA to warp so much that the hairspray just can't hold on anymore.
(Or you have a low spot in the glass, but that's not likely.)

You'll need to do two or three things, I'll give you the easiest options:

1. Spray hairspray onto the cold glass until it puddles, then smear it around everywhere until you have a thick even layer on the plate. Let it dry completely. That is your base coat. You don't wash it off between prints, you just add to it. (When you remove the print, you are probably going to have to freeze it off, but it should hold with that base layer thick enough.)

2. Take the fan guard off of the bed fan. It shoots the cooling power of that fan up exponentially. (Don't stick anything in it while it's running though, it's easy to do.)

3. Buy another desk fan to point at the back of the print. You want to cool that PLA off as quickly as possible so that it doesn't warp and twist the print. I use this one and it kicks ass, with a very small footprint.

http://www.amazon.com/gp/product/B000MF ... detailpage

4. It's counter-intuitive, but don't take the bed temperature up too high. (No higher than 60C for PLA, and that's with full fans blasting and no fan guard.) The warping problem is being caused by a temperature differential, you actually want to try to keep the bed temp down low enough that the differential is reduced. (I used to print PLA very successfully on bare glass at 45C.)

Ultimately, you'll also want to consider:

PEI surface for the borosilicate. It holds beautifully, without adhesive, but you would need to reset everything, so get to know "what is what with what you've got", first.

(And you'll probably want to put it on a heftier table or a desk. They really do kick a lot at high speeds.)

Not to worry though, you're just seeing PLA at it's finest. (Needs LOTS of cooling, fast.)

[Pekish79]

i had that too best way to solve no matter temperature and bed (i actually use 40 degree on zebra plate and nozzle varies from 195-220 depending on PLA filament (i never printed ABS or PTEG)

add a brim 1 layer 8-10 outline or 2 layer 6-7 outline (depend on filament the PLA-wood one very brittle i use 2 layer as 1 easily break by itself but usually just 1 is enough)

[naturalstate720]

Thanks for all the suggestions!

I lowered nozzle to 205, tried 40 and 50 temps.
Removed fan enclosure.
Sprayed the crap out of glass w/ frutis utlra hold. Added a small fan level with the highest bed state.

Printed bracelet at 40 and it didn't come off completely, but when it got to the lettering and was going very fast it slightly lifted up on one corner but didn't come off and successfully printed.
Started to print bigfoot (without respraying hairspray) and the whole thing became unstuck after about 10 layers.

It's also kind of cold here in the office too.

Should I spray respray every time and maybe do 60 degrees on bed? Could the shaking of desk have much to do with this?

Thank you!

[Pekish79]

if you spay you dont need to heat the bed at all...

the bigger the delta between the bed and the room the most will bent so the more you heat the bed the more it will bent

heat help holding down (true) but at same time make object bent (if the room is very cold) so if u decide to hold the first layer with hairspray or with glue you don't need to heat the bed and it will bent the least...

I will sill try a brim
https://www.simplify3d.com/support/tuto ... and-brims/

another thing is if you do Thin wall in an empty box (like ur building) it will bent more that if you have it all filled with 5% or 10% fill but obviously you will use more material and it will take longer

[Jules]

Yes, add some more hairspray between prints if it needs it, especially if you are still being a little stinting with it. (Wasn't kidding when i said to puddle it on the glass. )

Yep, you can certainly try increasing the bed temp a little. 60 is okay if the fan guard has been removed.

Slow your print speed down to 4200 mm/min. Slow and steady is always going to give you the best results with PLA. Give it time to bond without jerking things around.

Don't know if the jolting is affecting it, i have mine on a built-in desk. It doesn't move. (But you should eventually get it onto something stable.)

[jimc]

i can see that your print is warped from the side view. give me a well lit pic of the bottom so i can see how the first layer is going down. i can tell by looking at the extrusions on that layer if your bed gap is too high or low.

[naturalstate720]

Thanks again
but now I'm hearing conflicting info. I don't need to heat the bed at all if using hairspray? I know I've read multiple places here that the bed needs to be heated w/ hairspray w/ PLA.

[Jules]

Thanks again
but now I'm hearing conflicting info. I don't need to heat the bed at all if using hairspray? I know I've read multiple places here that the bed needs to be heated w/ hairspray w/ PLA.

Welcome to the world of 3D printing. People have different methods of doing things. In order to not use heat, you have to have your gap perfect. But feel free to experiment to determine which method works best for you.

If you keep cratering your prints with no heat and no hairspray, start using them again. (I always got a better print with a little heat. It helps the first layer to adhere better.)

[naturalstate720]

Lowered print speeds to 4200. Set temp to 60. Nozzle to 205. Also lowered speed to 30% on support, because it seems like supports sometimes get knocked over when going fast.

And I already see the corner pulling up, but it's slight. And this is a model that has fairly small footprint, about the size of a pack of playing cards.

What can I do next? Taking a pic now of previous print on bottom.