Your question is a good question but somewhat difficult to answer due
to the fact that there is no one burnout cycle that will work for
every situation. Oven size, wax type (or plastic type), oven
packing, part thickness/volume, and plaster type can all be factors
that will influence the optimal burnout cycle.
As for the worry about the flask cooling when it is removed from the
oven, this may not be the most important factor. The flask takes a
while to cool. Even though it has been out of the oven for several
minutes, the core of the flask will have seen very little cooling.
The steel liner will cool faster than the plaster. The plaster is a
good insulator for keeping the core of the flask hot. In addition,
the felt liner material that is used to reduce plaster cracking and
make the plaster easier to remove from the flask is also an
To really answer this question to the technical level of detail that
some on this forum anticipate, thermal couples can be cast in the
plaster to monitor the temperature distribution throughout the flask.
Eddie Bell of Rio Grande/The Bell group has conducted such
measurements for other flask sizes and reported the results in the
proceedings of the Santa Fe Symposium. I do not know if he has made
measurements for the flask size of the Ti-Casting unit.