Hello everyone 
I am new here. I have used other 3D printers in the past and I now run an H2D 24/7. It is an excellent machine and I appreciate the work behind it. I would like to share two observations that might help refine the user experience.
PLA drying in AMS 2 Pro at 45 °C without spool rotation
Observation
At 45 °C the humidity curve is flat for a long time. At 50 °C there is a clear initial rise of the sensor reading, which indicates moisture being driven out of the polymer, followed by a stable downward trend. This correlates with more consistent prints later.
Why 50 vs 45 matters. The drying rate depends on vapor pressure and diffusion in the polymer. Increasing air temperature from 45 to 50 °C increases saturation vapor pressure by about 29 percent. Diffusion below Tg also increases with temperature. With seated spools and a relatively stagnant boundary layer, the extra 5 °C makes a visible difference.
Workaround
If I need 50 °C with seated spools, I set my second AMS to a PETG preset and dry PLA at 50 °C there. Using the PLA preset at 50 °C with rotation also works but requires lifting the spools. PLA at 50 °C is still far from Tg, so the 5 °C increase is moderate.
Proposal
Add an expert option that allows 50 °C for PLA with seated spools. The current 45 °C feels too conservative for the no-rotation case.
PLA bed temperature vs speed
Observation
The default 55 °C works well for slow mode around 50 percent speed. At normal 100 percent I see occasional edge lift on complex parts. At sport and max the part can detach and the machine triggers a spaghetti error.
Workaround
First layer at 70 °C (sometimes even 75-80), then step down to 60 °C after a few layers (or not). This removed edge lift and prevented detachment for me at sport and max.
Proposal
For PLA on PEI: start at 70-80 °C for the first layer, then ramp down to 60 °C after layer 6-10 or after 1.2-2.0 mm height. Tie this to speed presets so the higher start temperature applies only when accelerations are high. At the highest speed, in my opinion, it should be 70-80 °C all the time, depending on the complexity and size of the model.
### Optional idea. Dew-point-aware drying target in AMS 2 Pro ###
Inputs. Ambient T and RH measured with both lids open and no spools.
Step 1. Compute dew point with Magnus.
Step 2. Compute ambient vapor pressure e = RH·es(T).
Step 2a. Empty-chamber check (optional). Close both lids, keep AMS empty, heat to a candidate Tc (e.g., 50 °C) for 30-35 min. RH should plateau near RHc_pred(Tc) within ±5 percentage points. If it is much higher, suspect weak airflow or sensor bias.
Step 3. For candidate drying temperatures Tc in 45 to 55, estimate in-chamber RHc = 100·e/es(Tc).
Rule. Pick the lowest Tc that gives RHc ≤ 20 percent. If spools do not rotate, do not set Tc below 50 °C for PLA.
Safety. Keep a default cap at 55 °C with an expert toggle to widen the range.
The above is a proposal that would solve the problem of different climates in rooms and thanks to this, each user would have a perfectly set drying temperature for some time (a week, a month)
Thanks for reading. I encourage you to discuss. Have a lovely day 