3D SYSTEMS, INC.
75-D059 REV_A
14
CRACKING OF PRINT BED
Description:
The surface of the print bed cracks open as the roller
moves across it .
Theory of Cause:
Excessive heating rate or temperature from the
heaters causes partial melting of material on the print bed surface(s) .
Short feeds caused by uneven powder feeds .
Mechanical problems with the roller can also cause cracking of the print
bed . If you suspect mechanical problems, contact 3D Systems .
Visual Signs:
Cracks appear on the surface of the bed .
Consequences:
If the part is printed in the area that is cracking, the part
will crack too .
Corrective Action:
Decrease the Print Heater PID Setpoint in 2 °C
increments until the cracks disappear .
If cracking occurs during the Warm-up stage, you may have ramped up
the temperature too quickly. Do not ramp to the final setpoint until real
time calibration starts, (6mm into the warm-up stage) .
CRYSTALS AND CONDENSATION
Description: During a print, a thin layer of needle-like crystals and/or a
film of condensation forms on cool surfaces in the print chamber.
The N
flow across the IR sensor and the laser window will keep the IR sensor
and laser window clean, although the user should inspect them before
every build .
NOTE: A slight amount of condensation will probably form
on the laser window every print. If the condensation is
extremely heavy across the entire window, call 3D Systems
Customer Service; this may indicate a problem with the
SLS system.
CURLING DURING
Description:
Edges or corners of the print rise above the print bed
surface .
Theory of Cause:
During the print, temperature differences in different
regions of the print cause uneven shrinkage, which, in turn, causes
curling . This usually occurs when the print temperature dips too low
after the material is added . Curl during printing can also occur if the
print bed temperature is too low .
Visual Signs:
The edges of the print rise above the print bed surface
after a layer is scanned . Curling usually occurs immediately after a layer
of material is added, but a delay sometimes occurs between the addition
of the material layer and the observation of curling .
Consequences:
Parts (especially those with large surface cross-sections)
are not flat.
If curling is severe, the print may shift in the print bed when the roller
passes it .
Corrective Action:
For
minor curling
, changes during the print may help .
This includes adjusting the Part Bed Set point and/or the Inner/Outer
Ratios .
Once
moderate to severe curling
has occurred, the part will continue to
appear curled even after adjustments have been made .
Curling and Z- Inaccuracy
Cracking of Print Bed
Crystals and Condensation
