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Purpose: Evaluate the difference in tablet press
compression dwell time as a function of D and B tooling and different
head styles such as domed and standard TSM. Additionally, compare
the dwell time computed as a function of the tangential velocity
and the head flat to that calculated from computer programs using
a 90% of peak force.
Method: Using a 10 station "B" and
an 8 station "D" Piccola tablet presses manufactured
by Riva and the Director data acquisition system from SMI a series
of tests were run. The tests were performed using materials considered
to be plastic, (MCC) and brittle, (di-calcium phosphate), on both
presses. On the "D" press two different types of head
geometry were used, the traditional TSM head and the TSM domed
style. The dwell times computer by the Director Program based
on the time at least 90% of the force was applied was graphically
compared to that computed based on the turret velocity and the
head flats.
Results: Dwell times for a domed "D"
head were virtually the same as for a standard TSM "B"
while the dwell times for a standard TSM "D" were much
longer. The results obtained were independent of the material.
Conclusions: Dwell times computed by the 90%
of peak force compare very well with the calculated dwell times
based on head flat and turret velocity and are independent of
material. "D" tooling with a domed head can be used
to approximate the dwell times of standard "B" tooling
while a standard "D" head will offer dwell times approximately
65% longer. A material sensitive to dwell times might be better
produced on a "D" tablet press utilizing standard TSM
head design. The same press could be used with a domed head to
project the performance of a press utilizing "B" tooling.
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