Design Guidelines - MakerBot Replicator 2X User Manual

DESIGN GUIDELINES

File Name: Massive Overhang Test
Design by: thingster
Thingiverse: 40382
File Name: Three 1:24 Windsor Chairs
Design by: PrettySmallThings
Thingiverse: 21999
OVERHANGS [Fig. 17.1]
As your MakerBot prints your object, each
layer of plastic rests on the one below. When
an object has straight sides, a new layer
will be fully supported by the previous layer.
But when an object has parts that angle
outwards (overhangs) some part of the new
layer is unsupported. If it's just a thin sliver of
the perimeter, the layer will still have enough
support, but if more than half of that outer
perimeter has nothing to rest on, you might
see drooping or dropped threads of plastic.
To make sure at least half of each layer's
Fig. 17. 1
outer perimeter is supported, avoid creating
overhangs that form an angle greater than
45° from the vertical.
BRIDGING [Fig. 17.2]
A thread of extruded plastic that crosses from
one supported area to another supported area
over an unsupported area is called a bridge.
Because the thread is supported at both
ends, the unsupported middle does not cause
problems. But if the unsupported section is too
long, you might see sagging in the middle. Your
MakerBot Replicator 2X should handle bridges
of 10 mm well, but you will probably see some
sagging on bridges of 20 mm.
DETAIL SIZE
There is no equivalent to pixel size on a
Fig. 17. 2 MakerBot. Layer height is used as a measure
of resolution, but it only measures resolution
in the Z-axis. Your MakerBot can produce its
finest detail on the Z-axis. The high quality
setting uses .1 mm layers, and it is possible to
produce layers that are even thinner. Design
with layer height in mind for even more
precision: a feature .2 mm tall will be two
layers tall when printed with .1 mm layers and
one layer tall when printed with .2 mm layers,
but will not be the correct height if printed
with .15 mm or .25 mm layer heights.
DESIGNING FOR 3D PRINTING 103