# 3D Printing > General 3D Printing Discussion >  Idea of controlling chamber temperature by adding temperature-controlled exhaust vent

## Batabus

Over the last five or so years, ABS warping has always come back to me for certain models.

Having perfect bed adhesion fixes the problem most of the time. However, it is just solving the symptoms. The internal stresses are still in the part. Increasing the bed temperature causes drooping and will still not solve the internal stresses in the model, which can get very large, depending on the shape. In the end, there are still temperature gradients present.

That is why some parts print fine for me, but become bent after removing them from the build plate.

Apart from looking at software which can simulate warping before printing, which I am also looking into, I just got an idea which I am curious to hear your opinions about.

This is the idea:

1. You thermally insulate the printer as well as possible.
2. You add a vent at the top of the printer which allows hot air to flow out.
3. You add one or more temperature sensors mounted close to the bed (so they are  at the same height of the bed regardless of the layer which is being  printed) but thermally decoupled from it (spaced around 10-20 cm. from  the surface).
3. A arduino a similar device is connected to the mentioned temperature sensors and to a small servo motor (i.e. a micro RC servo) driving a valve inside the vent, allowing it to partially close and open.
5. The arduino is programmed to fully close the vent if the measured chamber temperature is below 50 deg. C. Once it exceeds this temperature, the vent is gradually opened until the temperature is maintained stable at 50 deg. C.
6. Before printing, you heat the chamber by turning on the heatbed and extruder heater to normal printing temperatures. Once the chamber is at 50 deg. C, you start the print.
7. No more warping?

Could this work?

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## Petercat

Would there be any benefit to mounting the sensors to the extruder so that they would move with it and get readings across the print surface? Maybe mount them an inch or so away from the nozzle?
I doubt if cooling is the problem as much as_ uneven_ cooling is, though. At least that's what causes stress in castings, especially in materials that don't conduct heat very well.
As I recall, cooling large glass telescope mirrors is a process that must be carefully controlled over a period of _years_ to prevent stress distortion.

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## airscapes

I have a home made enclosure with a small heater and an InkBird thermostat.  With the thermostat set at 100F the small heater and heated bed keep the enclosure at 100F without external venting.  I put the sensor near my rambo board.. probably hotter up on the build platform.

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## Petercat

You could take care of that with a small recirculating fan somewhere in the case. I have an oil-filled heater in my bedroom, when I stand up my head is hot and my feet are cold. Adding a fan solved that problem!

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## Roberts_Clif

> I have a home made enclosure with a small heater and an InkBird thermostat.  With the thermostat set at 100F the small heater and heated bed keep the enclosure at 100F without external venting.  I put the sensor near my rambo board.. probably hotter up on the build platform.


I Too have a home Made enclosure, with a outdoor thermometer behind each 3D Printer and the temperature stays pretty close to 100F .
I do not have to do anything, however I have a bathroom vent with a light dimmer switch to vent smells outside. 

Have not had any problems with venting the smelly air outside.
Here is a sample of an ABS Print.

XY_C_Burly.jpg

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## curious aardvark

I can see going to this trouble for polycarbonate or nylon - but why do you still bother with abs ?

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## airscapes

For my purposes I find ABS to be much more rigid than any of the Nylon I have used (6xx, 910, EPA) or PETG.  Also the ABS MakerGear sells prints very nicely and is easy to print especially with the enclosure.  I have also not been able to stop the nasty warp of larger Nylon parts like I have with ABS.  It was actually not much work adding at $15 thermostat and a $30 heater.  Enclosure was built to keep the cats out of the mix :-)

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## -Will-

Maybe you could have the vent double as a fume filter. I don't know about you, but the fumes always get to me.

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## airscapes

My printer is in an extra bedroom.. with my home built enclosure, there is no need to vent anything. it does not smell, and it stays at 100F with heat and heated bed.. youi all make this much more complicated than it needs to be

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## Roberts_Clif

Every filament I have printed with has its indiviual smells.

Do not know why you can not smell it but they all smell.

https://ultimaker.com/download/13079/SDS%20ABS.pdf

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## airscapes

> Every filament I have printed with has its indiviual smells.
> 
> Do not know why you can not smell it but they all smell.
> 
> https://ultimaker.com/download/13079/SDS%20ABS.pdf


Sorry, what I meant was with the enclosure, the room does not smell..  Of maybe I have become nose blind..

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## Roberts_Clif

> Sorry, what I meant was with the enclosure, the room does not smell..  Of maybe I have become nose blind..



You must have a really good enclosure. 
My enclosure allows the smell even with the vent fan going an as soon as I open the door of the enclosure the smell increases.
Especially when printing with ABS.

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## airscapes

> You must have a really good enclosure. 
> My enclosure allows the smell even with the vent fan going an as soon as I open the door of the enclosure the smell increases.
> Especially when printing with ABS.


No, not really sealed.. probably nose blind ..

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## djprinter

As someone else mentioned, buy a cheap inkbird temperature controller and use it to drive a heating element (I use a cheap hair dryer set to low).

In my setup I also have an exhaust fan hooked to the cool side of the inkbird, in case it gets too hot.

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