Stratasys FDM 2000 Manual page 111

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Tips can work loose during the modeling process. This alters the
seams. Clean the tips and check the filament seals in the head
before starting each model.
If the modeler is left idle for several hours with material loaded,
the material may back up and form a hard ring around the fila-
ment, or buckle, preventing further flow. This is called back
flow. To help prevent this, make sure your liquefier is at the
recommended modeling temperature before you load, and AL-
WAYS make sure the filament is loaded before you place a new
nozzle on the FDM head. When not using the modeler for more
than one day, it is best to unload the material and lower the tem-
perature.
If back flow buildup occurs, do not run pulleys for loading. The
pulleys might slip on the filament causing damage to the pulleys.
Unloading Material
There are two basic ways to unload filament from the FDM modeler. If
you are changing material because the spool is empty, press "UNLOAD"
on the keypad unload for 10 seconds, open the head, and immediately
pull the filament out from the front of the machine. Then press "UN-
LOAD" again. If you are removing filament for any other reason, press
"UNLOAD", open the head and immediately pull the filament out from the
rear of the machine. Then press "UNLOAD" again. Trim the filament and
put the spool back in a sealed bag with desiccant to keep it dry.
Do not pull filament out from the head with significant force.
Tips and Toolpaths
Although Insight is preset with default values for toolpath widths in both
regular and support materials the operator is free to change these settings to
suit the specific needs of the model. There are some things to keep in mind
when making that decision.
When creating models, better resolution and quality is normally achieved by
using the smallest possible tips. At Stratasys, our engineers run 90% of the
benchmarks using default road settings, and 99% using a 0.012" tip. They are
the most successful settings for creating a high quality model.
Increasing the tip size may reduce modeling time, but it can also lead
to clumping or burning. This is a problem when a large tip is used to
make small roads. Supports built with large tips and roads are more
difficult to remove than those made with smaller tips and roads. In
general, we suggest that you use a small tip whenever possible.
When running roads with a width very similar in size to the height of the Z-
Notes
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Reference
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