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.
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3DUpfitters LLC20
