The
Speed
page covers parameters that control how fast various features of the object
are printed. The speeds are listed in mm per second, or as a percentage of a related speed
parameter.
The speed parameters are pretty
self-explanatory, especially if you've got
the
Show Help
check box set. However,
there's a couple of points I'd like to cover
about printing speed.
First of all, there is a relation
between your print speed and the
temperature you've set for the material
you're printing with. The basic rule is, the
faster you go, the hotter you print. This is
because as the hot end extrudes plastic,
it's constantly being cooled by the cold
filament that's coming in.
Setting the extrusion temperature
higher allows the hot end to melt the
incoming plastic at a faster rate. This
allows you to print more quickly. The
relation between print speed and
extrusion temperature is one of those
things you'll get a feel for as you gain
experience with your printer.
You'll quickly learn that the Eris® will “talk” to you if you're printing too rapidly for a given
temperature. The extruder will begin to “skip” periodically (or frequently, depending on how fast
you're going). A skipping extruder has a very distinct sound – it's kind of a light bump or
knocking. If you watch the manual feed knob on the extruder, you'll notice that it will briefly
rotate in the opposite direction at the same time you hear the skipping sound. The skip is
caused by the hot end's inability to melt the material is rapidly as is required. The pressure
builds up until the stepper motor can no longer generate the force required. At this point the
tension in the filament is released like a spring and the filament pushes back with enough force
to cause the stepper motor to skip steps, resulting in a short reverse rotation.
Secondly, there is also a direct relation between print speed and print quality. In the
image above, you'll notice that the speeds for print moves vary a bit. This is because some
features don't require a focus on surface quality.
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