LulzBot TAZ 4, User Manual

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2.5. EXPERT MODE
Figure 2.35 shows the strategy adopted by Slic3r. Reading from right
to left, when the minimum fan threshold (#2) is reached the fan is turned
on. This increases in intensity as the layer time decreases. The print
speed remains constant until the estimated print time drops below a certain
threshold (#1), this is when the print speed is reduced until it reaches it’s
minimum value.
Fans
Most electronics and firmware allow the addition of a fan via a spare
connector. These can then be instructed with G-code, from Slic3r, to turn
on or off as the model requires, and to rotate at different speeds.
Care should be taken with the positioning of the fan so that it does
not cool any heated bed more than necessary. It should also not cool the
heater block of the hot-end so as not to force it to do more work and waste
energy. The air movement should aim for the nozzle tip, flowing over the
freshly extruded material.
A duct may help in guiding the flow correctly, and there are several
designs available online, for a wide variety of printers.
Slowing Down
Slic3r can tell the printer to slow down if the estimated layer time is above
a certain threshold.
Care must be taken as the intended effect could be mitigated by the
nozzle not moving far enough away from the fresh extrusion, a problem
with small, detailed layers. For this reason it is usually recommended to
use a fan where possible.
Configuring
In simple mode Slic3r will attempt to choose the optimal settings for both
fans and speed. Expert mode gives more granular options.
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