Idea of controlling chamber temperature by adding temperature-controlled exhaust vent
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?
