This is the precise reason why I dislike using RH for this. The RH has dropped, but the air is exactly 0% dryer just because the temperature is higher. There’s no less moisture present, and the hotter air does not inherently “draw” more moisture out of plastic. This is a major reason why we use dew point in industrial drying systems.
You need heat, airflow, and dry air. A lower RH at 80C is not at all dryer than it was at 25C. To that end, I made this chart the other day. This is based on the actual dew points needed to dry plastic, with PLA, PETG, and Nylon used as approximate examples.
In actuality, PLA can be “usable” at higher values than shown here, such as around 8-10C dew point, but the reason for this was to illustrate my belief that 3d printer owners would have success if they could manage to achieve a ~5% RH at “room temperature”.
To answer your question about factories, we use desiccant systems and pull the dew point down to -40 degrees or lower.
It would seem that Claude just converted these RH using dew point. I asked it to strictly convert air merely heated with nothing else. I get the reasoning about it being descriptively misleading.
If your color code is to be used a good dryer setup that dried filaments effectively per empirical testing is at least able to remove 15 dew points inside, vs. a sealed heated plastic box. Which aren’t too far off from the offerings of some “3d printing dryers” esp. older ones.
Modern dryers can purge moisture and they help reduce the dew point to some degree but all you need is good quality desiccant and you’re going to achieve nearly industrial quality drying.
I use alumina desiccant and it’s able to pull the RH of my AMS down to “0%” with ease.
It’s currently sitting at “4%” after having opened the AMS, swapped all 4 rolls, dried them, opened it again to fix a fault, and its been a week since I regenned it last. I just ran a 3 color print with sunlu PETG with no blobs, zits, stringing, or any other defects.
Happy with my first test - PETG Matte White. Default settings, .4mm, dried before use. Very happy with the color, a close match to the HF. Now I need to tune it for a .6mm nozzle.
