Prints warping help

[Zaf]

Hey Guys,

I've had this issue for sometime now and only just thought to see if OcUK has a 3d Printing sub-forum lol

I'm printing with PLA and my bed temp is set to 50DegC

The bed is magnetic but I've had the same happen with metal and glass beds too.

Any suggestions to stop this from happening?

 

[Zeeflyboy]

- Clean it well (read instructions for your bed surface, but usually can’t go too far wrong with IPA).

- Leaving fan off for first 2-3 layers will help adhesion.

- go slower and/or slightly hotter extrusion temp on first layer

- go lower on first layer, or increase flow for first layer.

- for PLA you can try a cooler bed temperature somewhat counterintuitively. It softens a lot around 50-60c which can actually make issues like this worse where at cooler temperatures it would be rigid enough to resist it. On top of that part of the reason for the warping is the temperature gradient between top and bottom, so reducing temps (as they aren’t really needed for PLA to stick well to most surfaces) can reduce the gradient thus reduce warping tendency.

- for particularly troublesome geometries with little bed area in contact, consider a brim.

- if all else fails try a different surface. PEI coated spring steel plate will fit on your magnetic bed, or try print bite+ (Again ideally on a spring steel bed imo for ease of removal) which is excellent in my experience. Alternatively try an adhesion promoter like dimafix etc.

 

[Zaf]

Thanks for the informative reply mate, much appreciated.

I’ll try your suggestions on my next print and will see how I get on!

Thanks again

 

[Haze]

bed is too cold, try 60/70, i run my fan at 50% the whole print

 

[Rroff]

Sometimes I've found micro-adjustments of the bed height (even when it should be level) or increasing the temperature helps - but sometimes I've had to resort to using a good layer of Pritt stick - nothing else seems to work sometimes even the stuff intended for it like Dimafix.

(Just make sure you clean it up well before and after).

 

[Zaf]

Did another test print earlier and tried Haze's suggestion... It's better and wasn't rocking side to side while printing lol but it's still nowhere near perfect!

Think I'll try some decorators tape next

 

[RevBillyG]

Assuming your using Cura, try giving Cheps profiles a go.
https://www.chepclub.com/cura-profiles.html

 

[Zaf]

Thanks Rev but I'm already using Chep's profiles.

I think my bed is warped as when I move the print from centre, I get a much better print.

Still not perfect but much better. I've not tried using a Brim yet but I think that will help. I'm going to give Prusaslicer a go on my next print.

 

[bulb66]

Firstly as already said 50°c is too low for the bed temp 70°c would be my recommendation.

You don't say what temperature you printing at? For the first layer I would print 220°c, the 210-215°c for the rest.

This might seem an odd question, but have you sanded that bed? I can see you've printed to close before but I think the pictures above you aren't close enough.

 

[Zaf]

I've currently got the bed at 70°c and I'm printing at 210°c.

The bed hasn't been sanded it's a brand new magnetic bed.

I'm going to give Prusa slicer a go, as apparently the overall print time is quicker than Cura with no change in quality.

 

[RevBillyG]

Looks like the layers are cooling too fast.
No draughts near the printer? Is the room cold?

 

[Haze]

I had problems with the metal bed, it's normal for metal beds not to be perfectly flat, I invested in a glass bed about a week after buying my ender 3, tried tape on it, but glue sticks ftw

 

[Zeeflyboy]

Honestly with PLA it doesn’t need to be 70… that’s well above the glass transition temp and will make it super soft at the bottom and much easier for it to bend.

Normal max recommended for PLA is 60 on the bed (which is what I generally have used over the last decade or so without much issue!), and when I’ve had the rare issues with certain types/brands of PLA lifting I’ve had better success going colder rather than hotter. You can lay down the first layer a bit hotter at 215-220 and a tad slower which can also help. PLA doesn’t even need a heated bed at all in reality and can be printed onto cold

have you tried my suggestions in the first post?

I would also take the bed off and give it a really good clean with hot water, soap and a scrubbing sponge, then a wipe with IPA or streak free window cleaner…. Just to make sure there are no oils from your hands ruining the adhesion.

 

[bulb66]

Honestly with PLA it doesn’t need to be 70… that’s well above the glass transition temp and will make it super soft at the bottom and much easier for it to bend.

Normal max recommended for PLA is 60 on the bed, which is what I generally use, and when I’ve had issues with certain types/brands of PLA lifting I’ve had better success going colder rather than hotter. You can lay down the first layer a bit hotter at 215-220 which can also help. PLA doesn’t even need a heated bed at all in reality.

have you tried my suggestions in the first post?

Your assuming that the temp on the top of the print surface is at 70°c, adding a magnetic surface and then a metal plate and then the faketak on top.

 

[Zeeflyboy]

Faketak lol, love it.

I’m not assuming anything though, PLA glass transition is around 60-65c and already gets very soft and bendy well before that… putting the bed at 70 is going to make the PLA extremely soft even after losses through the bed which will generally only exacerbate any warping issues when already present. I myself currently print on a tool plate aluminium bed, magnetic plate, spring steel and printbite+ so I’m well aware of the thermal losses involved.

From past experience while most works great at a nominal 60c, when I’ve had the occasional troublesome PLA brand lifting I’ve tried going hotter and had it end up worse… dropping down to 45-50 (and upping the first layer extrusion temp) solved it almost every time. It's pretty counterintuitive and indeed the opposite of what you would do for many other materials, but remember one of the big selling points of PLA over ABS back when it first started gaining popularity was how it can be printed without even needing a heated bed...

It’s just a suggestion for something to try from my own experience over many, many years of printing countless materials and brands... Given he’s already tried the bed at 70 and still had it lifting off the bed I would suggest trying going the other way too (and trying the other suggestions).

Ultimately I never particularly loved buildtak, I think there are much better surfaces out there. That said PLA should be able to be printed without issues.

edit - can you take a picture of the first layer so we can see how it’s laying?

 

[Zaf]

Since changing the orientation it is printing a lot better, but there is still a slight rocking horse effect rather than being completely flat.

I've finished printing my speaker stands now but will try and do some test prints tomorrow and take a photo of the first layer.

 

[Dr Who]

I normally go with 70 degrees bed temp for first layer then 60 degrees for the rest of the print. Get yourself a digital infrared thermometer to check the bed temperature.

 

[Scougar]

P.s. when we say clean the plate... you should take it off and use hot water and dish washing detergent. PLA leaves slippery residue and you will see it as soon as you put hot water on it.

After that, alcohol to get off any residual grease and you should be good to go. Obviously PLA likes to be squished slightly.

Also. Use a brim.