LulzBot TAZ 4, User Manual

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Slic3r
The Important First Layer
Before delving into producing the first print it is worthwhile taking a little
detour to talk about the importance of getting the first layer right. As
many have found through trial and error, if the first layer is not the best it
can be then it can lead to complete failure, parts detaching, and warping.
There are several techniques and recommendations one can heed in order
to minimise the chance of this happening.
Level bed. Having a level bed is critical. If the distance between the nozzle
tip and the bed deviates by even a small amount it can result in either the
material not lying down on the bed (because the nozzle is too close and
scrapes the bed instead), or the material lying too high from the bed and
not adhering correctly.
Higher temperature. The extruder hot-end and bed, if it is heated, can be
made hotter for the first layer, thus decreasing the viscosity of the material
being printed. As a rule of thumb, an additonal 5° is recommended.
Lower speeds. Slowing down the extruder for the first layer reduces the
forces applied to the molten material as it emerges, reducing the chances
of it being stretched too much and not adhering correctly. 30% or 50% of
the normal speed is recommended.
Correctly calibrated extrusion rates. If too much material is laid down
then the nozzle may drag through it on the second pass, causing it to lift
off the bed (particularly if the material has cooled). Too little material
may result in the first layer coming loose later in the print, leading either
to detached objects or warping. For these reasons it is important to have
a well-calibrated extrusion rate as recommended in §2.3).
First layer height. A thicker layer height will provide more flow, and
consequently more heat, making the extrusion adhere to the bed more. It
also gives the benefit of giving more tolerance for the levelness of the bed.
It is recommended to raise the first layer height to match the diameter of
the nozzle, e.g. a first layer height of 0.35mm for a 0.35mm nozzle. Note:
The first layer height is set this way automatically in simple mode.
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