ABS warping on edges

[gabrielwong1991]

Printer Model

Voron 2.4

Extruder Type

Orbiter

Cooling Type

Other

Hi I have a Voron 2.4 r2 300mm and recently added Ellis bed fan mod https://mods.vorondesign.com/details/28xgztUufAtAfV4XUL5l4w .

I find that if i use the ellis bed fan mod, my model warps on the edges.

Just want to understand if anyone have this problem?

My guess is that when the fans are on, the build plate edges are colder due to air blowing on the edges of the plate.

If I turn it off during print it does not warp at all.

Could it be I am using 250mm heating mat but then it is standard size for 300mm build?

Just want to know how to approach this problem. It is good to have it as it makes reaching the chamber temperature faster...

Thanks.

 

[NoGuru]

Are you preheating the chamber?

Do you have the fans reduce speeds when you get your target chamber temp?

You only need very low fan speeds to circulate the air. ANY breeze will be colder then the filament and cause warping.

 

[gabrielwong1991]

Are you preheating the chamber?

Do you have the fans reduce speeds when you get your target chamber temp?

You only need very low fan speeds to circulate the air. ANY breeze will be colder then the filament and cause warping.

Hi, I am preheating the chamber as with the Ellis mod macro.

Basically the fan speed is at low until the bed temp reaches temperature of 100 degrees. Then the fan speed will be high until the chamber probe detects 50 degrees. It then sat there for 5 minutes with high.

When the print starts the macro set fan to low (40%), chamber temp stays roughly the same.

Interestingly, if I set the fans off, the chamber temp gradually falls to around 43 degrees while it is printing but it does not warp at all.

How do you set your fan speed low? at what percentage?

 

[lord-carlos]

Just for a quick test you could swap the 40% out with 20%.
Also might throw a blanket / quilt / cover over the printer to isolate it.

Not necessary as the final solution, but just to see how this affects your ABS prints.

There is a thread on the voron discord that specializes in isolating the print chamber for higher temps. Might want to check that out if the blanket "hack" works out for you.

Another idea is to remove the bed fans on the edges and just keep the center ones. Or drive them individually and just power the outer ones during pre-heat.

 

[NoGuru]

You can go in and edit the macro. For example change the variable from .6 to .3 after target is reached and see how it goes.