To accurately evaluate the papermaking potential of pulps it is necessary t
o reproduce, as closely as possible, machine-made sheets in the laboratory.
A new laboratory sheet former, the MBDF, has been developed at Australian
Pulp and Paper Institute (APPI) for producing 220 by 220 mm handsheets that
reproduce certain features of commercial paper. This former uses headbox s
tock concentrations that are close to paper machine values, a commercial fa
bric, high frequency vacuum pulses and programmed vacuum profiles. This pap
er describes the forming process on the MBDF and discusses formation and st
rength properties of handsheets made on the MBDF.