It says in the technical datasheet of Easy Composistes out-of-autoclave Prepreg XPREG XC110, that for curing the "minimum vacuum pressure is 10mbar". This is a pretty low value. There are many vacuum pumps that can only achieve 50mbar, for example.

So my question basically is: why so low? To reduce the probability for pinholes? Because the relative gain in pressure when going from a 50mbar vacuum pump to a 10mbar vacuum pump is very small when you compare it to the outside pressure of a thousand mbar (well: 960mbar where I live).

Okay so lets assume I had an autoclave capable of generating an overpressure of 10bar (a whopping ten thousand mbar). Additionally the prepreg in its mould is vacuumed but now the difference between the mould pressure of 10mbar or 50mbar is even smaller: when the autoclave pressure is 10,000mbar, reducing the pressure in the mould from 50mbar to 10mbar results in a pressure increase of just 0.004 percent. So just from a pressure standpoint this gain is marginally. Is it still worth it to go for the 10mbar vacuum pump over the 50mbar pump in order get out that extra bit of air and thus decrease pinhole probability?

So in short: when using a 10,000mbar autoclave, does it matter if the pressure in the mould is 10mbar instead of 50mbar?