Quote ......Once the mold is filled, it is moved to the vibrocompaction area, where massive presses squeeze the material to roughly half its original thickness. At the same time, a vacuum is applied and the mold vibrated to evacuate the air."......
unquote
There has been a number of posts about vac/pressure, possibly started from the original posting partially quote above.
On my reading of it, the press in merely a mechanical press not air pressure in the mould.
So you have pressure and vacuum.
Regards
John
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