If the maximum internal temperature is the goal, then being airtight also doesn't help since the
main cause of heat loss is through conduction through the sides of the enclosure, not through
small amounts of air loss. A bottom doesn't help either since while heat doesn't rise, hot air
does, and thus almost all of the heat of an enclosure is at the top. A bottom is helpful,
however, if your table is too small for the enclosure.
Since airflow is key, all of our enclosures come with fans chosen for CFM ratings to match the
cubic size of the enclosures. This ensures that for cool-loving filament types like PLA there's
enough airflow to keep the temperatures in the safe zone.
Room Temperature
Passively heated enclosures are completely dependent on the room temperature as a starting
point. If you're trying to print ABS in an unheated garage in the winter the temperature inside
the enclosure is never going to get hot enough. The reason is the bed heater has only enough
energy to increase temps from the baseline. If that baseline is 22C, then you've got a good
chance of getting into the sweet spot. If the baseline is 13C, then you'll be lucky to warm the
interior of the enclosure hot enough to print materials such as ABS.
ABS and Nylon
You want the internal temperatures higher for filaments like ABS, which happens naturally
because the recommended bed temperatures are much higher. With the fans turned on we
shoot for internal temps between 35C and 40C for 3D printers that use E3D hot ends because
E3D recommends that temp range to avoid clogging. Keeping the temperatures in that range it
puts the least stress on the equipment and follows the manufacturer's guidelines.
This works great for people either interested mostly in air quality or those who are risk-averse
and don't want to take a chance of clogging their hot ends or decreasing the useful life of their
printers.
More experienced 3D printer owners though, those for whom a clogged nozzle is a known risk,
might want to run the temperatures higher for less chance warping of ABS parts or to print
nylon. In those cases, you can turn o
ff
the fans or even print one of the vent covers and just
not vent at all. For our internal print farm, we do the later on a couple of machines where the
temperature when printing ABS gets as high as 46C. They've been running like that for years
with no filament clogging. Even with no venting of the power supplies, we've never had a
power supply fail either. Obviously, your mileage may vary, as it depends on a lot of variables
such as filament quality and the quality of the power supply in that particular printer.
If you're looking for the highest temperature's possible, try turning the bed heater on for an
hour before you print.
Copyright 2020 3DUPfitters LLC
15
