LulzBot TAZ 4, User Manual

Page: 39 / 133

2.3. FIRST PRINT
Fatter extrusion width. The more material touching the bed, the better
the object will adhere to it, and this can be achieved by increasing the
extrusion width of the first layer, either by a percentage or a fixed amount.
Any spaces between the extrusions are adjusted accordingly.
A value of approximately 200% is usually recommended, but note that
the value is calculated from the layer height and so the value should only
be set if the layer height is the highest possible. For example, if the layer
height is 0.1mm, and the extrusion width is set to 200%, then the actual
extruded width will only be 0.2mm, which is smaller than the nozzle. This
would cause poor flow and lead to a failed print. It is therefore highly
recommended to combine the high first layer height technique recommended
above with this one. Setting the first layer height to 0.35mm and the first
extrusion width to 200% would result in a nice fat extrusion 0.65mm wide.
Bed material. Many options exist for the material to use for the bed, and
preparing the right surface can vastly improve first layer adhesion.
PLA is more forgiving and works well on PET, Kapton, or blue painters
tape.
ABS usually needs more cajoling and, whilst it can print well on
PET and Kapton, there are reports that people have success by applying
hairspray to the bed before printing. Others have reported that an ABS
slurry (made from dissolving some ABS in Acetone) thinly applied can also
help keep the print attached.
No cooling. Directly related with the above, it makes no sense to increase
the temperature of the first layer and still have a fan or other cooling
mechanism at work. Keeping the fan turned off for the first few layers is
generally recommended.
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