Powder density determined after mechanically tapping a container holding the sample.
Also called: tap density; tapping density.
What does tapped density measure?
Tapped density is powder mass divided by the volume occupied after a defined mechanical tapping sequence. The powder bed can settle into a smaller volume without the solid material itself becoming denser. It is a packing-state measurement, not a true-density measurement.
The tapping method is part of the result. Apparatus motion, cylinder arrangement and the selected measurement procedure need to be identified. A number labelled only “tapped density” is an incomplete basis for comparison.
Is any volume read after tapping the final result?
No. An intermediate reading records the bed volume at that stage. The selected method’s volume-change endpoint determines whether further tapping is needed.
Information needed beside a tapped-density number
Report field
What it clarifies
Method and container
Which measurement configuration was used.
Tapping motion and sequence
How the bed was mechanically settled.
Reading stage and endpoint basis
Whether a volume is intermediate or the method-defined result.
Mass, volume and units
How the reported density can be checked.
Can tapped density predict capsule fill weight?
It can support density-based comparison, including Hausner ratio and Carr index, but it does not reproduce every dosing mechanism. Neither the poured nor the tapped value alone establishes the effective density inside a filled capsule. A fill-weight estimate still needs a justified density for the filling situation.