Question

bj: post-processing
use the information below to answer the question.
with binder jetting, many of the post - processing procedures are done at the facility
that did the printing.
the first thing that happens after printing is that the print must remain in the powder
bed so that it hardens. once it is taken out of the bed, the excess powder is removed
with a high - pressure air hose.
sand
if the object is a full - color sand print, the process is complete when the excess powder
is removed. however, a dye can still be added for additional color. an
infiltration process can also be added to the post - processing to add more mechanical
structure to the print. this is done by adding a clear coat to the print which can help it
feel smoother and protect it. when a sand print is to be used as a mold, there are
secondary heat treatments to give it a better binding as well.
metals
sintering is a requirement for metal prints. this sintering is done with the use of an
oven for binder jetting (bj) metal prints. once this has been done, the process is
complete. the process can be continued with a bronze infiltration to give it better
mechanical properties.
what can be added to a binder jetting (bj) sand print to
make it feel smoother and protect it?
a clear coata dyea bronze additivea powder covering

Explanation:

The text clearly states that for a sand print, adding a clear coat can make it feel smoother and protect it. A dye is for additional color, a bronze additive is for metal prints (not sand prints in this context), and a powder covering is removed in the process.

Answer:

a clear coat