How to avoid PLA warping ? (plus question about temperature calibration)

[holoped 0]

Hi,

I'm printing some large flat PLA parts,

and they warp noticeably at the corners.

I'm using Cura at 0.1mm, 210c, 70mms and with Brim.

Printing on green painter tape applied on the original acrylic bed.

The part will warp and lift the tape with it.

Any ideas ?

Will blue painters tape work better ?

I tried printing at 200c, but I get jams so I suspect that the real temperature

is actually lower than what the thermsistor is reporting.

I have an IR temp gun, which reports 150c when I set the hotend to 220c.

I don't think that reading is correct though.

How do I calibrate or measure the hotend temperature ?

Thanks.

 

[corngolem 0]

If the corner is near the edge of the tape strip then it's going to warp a lot more than if it was in the middle of the strip. Masking tape is made to be removable, so it doesn't stick that well.

You could try printing anchors (helper disks).

Or get rid of tape and use hair spray (must contain vinyl) but in this case it will stick so well that you risk breaking your part during removal (talking about this I'm interested in solutions).

 

[illuminarti 18]

As CornGolem notes, the edges of pieces of tape are not your friend. I recommend using the widest tape that you can find, and wipe it down with isopropyl alcohol before you start printing. That seems to help with both the adhesion of the print to the tape, and tape to the bed.

I don't know about other types of tape - but 6"-wide Scotch 2090 Blue Tape treated with alcohol will hold down perfectly pretty much any PLA print that I try.

You may also want to not use the fan for these prints - just set a nice slow minimum layer time, such as 10s.

 

[valcrow 145]

If you don't need the bottom to be completely smooth/flat or you're going to mount it on something anyways. Boolean some pyramids out all along the bottom.

 

[holoped 0]

Thanks everyone. I'm going to find some 6" tape and alcohol and try it.

 

[SandervG 1,521]

i have a few other tips for you:

Print at a lowest possible temperature

Print with as less infill as possible

Put the tape over the entire build platform, and have it run over the bottom (so don't cut it on the engraved markings).

Make sure the tape is pressed on the platform

Make sure your first layer is pressed in the tape

Make the corners of your print round, if possible.

Print with a raft, so the raft will warp instead of your print

In Cura we also have a new setting called Brim, which is suppose to help against warping.

Use blue painters tape on the bed and to wipe the tape with isopropyl alcohol (aka rubbing alcohol - found at any drug store).

 

[gr5 2,265]

You were successful at getting part to stick to tape so now you need tape to stick to acrylic. Use wider tape as Illuminarti says.

 

[aaron 2]

I have found that it helps if you turn the object in such a way that the longest flat parts are 45 degrees offset from the seam lines of the masking tape.

 

[printedsolid 3]

You could also do away with the tape entirely. I use a piece of plate glass treated with either aquanet hairspray or dilute white school glue/glue stick.

I suspect a little bit of glue stick on top of the tape where the corners are peeling might also help.

 

[nick-foley 5]

Printing directly on the acrylic bed will solve your curling problems 100% - but you probably won't be able to remove the part in one piece when it's done!

What we do is remove the blue tape in patches wherever the corners are peeling. That way, you have the great adhesion of PLA on acrylic where you need it, and the ease of removal of PLA on blue tape for the rest.

 

[printedsolid 3]

@Nick, sounds like a neat trick!

 

[aaron 2]

has anyone tried to print pla on kapton tape?

 

[printedsolid 3]

I've tried it with fairly small objects.

Kapton + Glue stick. Heated to 55C. Seemed to stick really well. Needed pliers to remove the part.

Can't say how it would have worked for more challenging parts.

 

[illuminarti 18]

Would be interesting to try with Glue stick... I've printed straight on Kaptop tape before. Works really well for large flat parts that have a lot of contact area, provided they aren't very tall - because there's not enough adhesion to resist much warping. Gives a nice glassy smooth bottom surface though.

 

[gr5 2,265]

I've printed on cold kapton tape and it doesn't stick well but good enough for easy prints. On a heated bed at 70C with PLA it sticks quite well but at 60C it sticks no better than room temperature.

 

[peggyb 171]

what also works:

print with a brim, and tape some tape or duck tape over it when its done.

don't push too hard on the build plate!

 

[aaron 2]

I like the idea with taping the brim. May have to try it sometime.

 

[kochen 0]

what also works:

print with a brim, and tape some tape or duck tape over it when its done.

don't push too hard on the build plate!

 

 

That print looks good, could you please share the settings on this one?