Basic idea of vacuum die casting

Basic idea of vacuum die casting

Vacuum industrial definition

「Pressure of specific space is lower than atmospheric pressure」(JISZ8126)

Image of basic idea

< Reference Vacuum unit >

P2(Specific space )<P1
(Atmospheric pressure)
‍
1atm=760Torr
=1.01325×105Pa=1.01325×102kPa
<Refer, Unit vacuum>

Low Vacuum 100kPa～ 100Pa
(Common vacuum die casting)
MidVacuum 100Pa ～ 0.1Pa
HighVacuum 0.1Pa ～10-5 Pa

Basic-P2

Vx S > V1x S1

Please refer to left picture, cross section of valve is decided by following condition.

Exhaust speed V=250 〜 280m/s (Sound velocity 340m/s)

V ： Exhaust speed
S ： Valve cross section
V1 ： Plunger speed
S1 ： Plunger cross section