large rectangular part in ABS: all four corners bent upwards after about one day printing

[OliverO 0]

Hello,

I'm printing a large rectangular housing part in ABS. No matter what fill grade or wall thickness, the corners will always start to bend upwards from the built plate after about one day of printing. I assume that the high temperature gradient from the built plate to the current layer is causing this deformation. The adhesion is usually quite good even after the print cooling down at room temperature (before putting it into the freezing chamber).

Why is the built plate temperature not lowered to the surrounding air temperature after the completion of the first layers? 

Thanks for any hint and have a good day!

Oliver

 

[PizzaTijd 5]

Have you tried printing with a brim?

[JTMD 19]

I print exclusively in ABS and ASA.  Although Ultimakers are among the best of the consumer printers at ABS, it's still a challenge..  here's what I do:

if you have an air handler or something similar, set workspace temp to 50C so the fan wont come on and cover printer with a nice thick blanket.  Doing so I see workspace temps of about 140F..  it helps. I have a couple of small aux heaters that I add to get the temps up in the summer (air conditioned office).  high build space temp will make the biggest difference. (Check the commercial printers, they get so hot they have a locked door while running)
A wide and thick brim can help.  Thick since ABS can even pull a brim up if it's too thin.  I'll sometimes actually design the brim into the model so I can make it thin where it touches the part to make it easier to trim, but the rest is thick.
Lately I've been printing on a plastic-coated surface - no glue or hair spray - that's helped a lot.  I use the WamBam product but there are others.
If you're designing the part, avoid vertical walls meeting in square corners if possible.
 

[43915 16]

I'd try a thinner layer of glue. It looks like you have quite a lot of glue on the buildplate, and I've noticed that when I put too much of it it won't stick as well. I just run the gluestick in a zig-zag motion over the glass and then take a pretty wet paper cloth or similar and wipe it around until I don't see any solid glue left. Then I try to wipe the paper smoothly over the entire glass so that it leaves an even layer of moisture/gluey water. When that dries it will leave a nice thin layer of glue that works much better for me.

 

I also find that a slightly higher bed temp makes a big difference as well. It's been a while since I printed with ABS, but IIRC I used to put the bed temp at 105c. Just 5-10 degrees lower and the warping became much worse. High bed temp and as low as you can go on fan speed.

 

And like the others recommend, a big brim can work wonders. The experimental setting "Draft Shield" in Cura could also be something worth trying.

[OliverO 0]

Hello,

many thanks for all the suggestions! I thought that lowering the bed temperature after the first let's say 10 layers would help already, because the big temperature difference between bed and material would cause the deformation. If the temperature would be everywhere nearly the same then there should be only a minimum deformation, even if the part is not designed according to the rules for plastic parts (->  mainly minimizing of high temperature differences withing the structure during the cooling down phase, e.g. in corners).

 

I used different adhesion agents before and the result was always the same (I canceled some earlier builds after it started to bend in the corners). Now I use the glue stick, because I ran out of the other agent. The wet paper method is a really good idea.

 

Following the suggestions of both posts (can the solution be shared?), I'm trying now the following:

- increasing the bed temperature to 105°C

- closing all gaps with tape (doors)

- covering the rear fan (I didn't find the option to set the work space temperature higher)

- lifting the model 2 mm in z-direction, which creates a thick layer of breakaway support material, that prevents the direct contact of the part with the hot bed

 

Greetings and have a good day!

Oliver

 

 

 

 

 

[JTMD 19]

5 hours ago, OliverO said:

- covering the rear fan (I didn't find the option to set the work space temperature higher)

 

 

In Cura, under "Material"   look for: "Build Volume Temperature"   Its the first parameter, you might need to change the visibility setting in preferences to see it.

 

I set it for 50.0 C.  You can set it for 0 which is supposed to not try to control the build volume temperature but I'm able to get higher temps using 50.  I don't know what setting it to 0 actually accomplishes.

I don't think blocking the fan is a good idea.
I used to use a raft of breakaway material and hairspray on the glass (glue stick is SO neanderthal 🙂) But the plastic coated build surface works a LOT better for me without any other adhesion witchcraft.
WamBam PEX coated build plate system    ( fits the S5 - there are other sizes for other printers)

[OliverO 0]

On 8/25/2023 at 1:55 PM, JTMD said:

 

In Cura, under "Material"   look for: "Build Volume Temperature"   Its the first parameter, you might need to change the visibility setting in preferences to see it.

 

OK, thanks...there it is and it's now visible in my list of settings 😉 .

 

The next try stopped printing because of error84 after one day...and I found deformations like an overhang on vertical walls...and the corners lifted up again.

 

I start now another try with a slightly higher bed temperature (90°C) and the build volume temperature set to 50°C (the air manager fan doesn't turn). Additionally I wrapped bubble foil around the device in order to maintain a more uniform temperature.

In the end I think it is my design which creates the trouble (large volume). But as it is for a prototype I can deal with small defects.

 

I will search also for reseller in Europe and try the flexible build system from Wham bam.