Magnum Venus Plastech Flex Molding Process MKVI Mix - Manual (Page 55)

MKVI Mix Meter System Operations Manual
Rev. 08/2013 Page | 55
Mould Pressure Guard (MPG):
The machine features a Mould Pressure Guard (MPG), which is used to control the
maximum allowable pressure at the mixing head. This can be utilized to provide line
pressure control during an injection, or as a safety mechanism to prevent the line pressure
from exceeding the maximum working pressure of the injection line to the mould.
The MPG block is shown below. The blue air-line supplies air from the MPG pressure
regulator on the control panel. When fluid pressure at the injection head exceeds the
MPG preset level, shown on the MPG pressure gauge, the internal diaphragm moves
and leaks air from the red air line connected to the control circuit. This causes the
machine to slow and stop.
MPG Operation:
1. Set the maximum injection pressure on the MPG preset level gauge using the MPG
regulator. (Suggested initial setting
– 2 bar)
2. If the resin pressure is below the preset pressure, then the automatic regulator will
remain fully open allowing full main pressure to the resin pump regulator.
3.
If the resin pressure exceeds the preset level, the ‘MPG signal pressure’ will reduce
proportionally closing the automatic regulator and limit air pressure to the resin pump
regulator. This slows or stops the resin pump, reducing resin pressure until it
matches the preset level. During operation, a small leak of air will occur from the
MPG sensor block. This is normal.
4. The MPG preset level may be adjusted during an injection to achieve optimum pump
output speed at the safest injection pressure.
5. Several factors will affect the optimum setting of the MPG regulator, e.g. fiber volume
fraction, mould size and rigidity, resin viscosity, required resin delivery rate etc.
Blue Air Line – MPG
set pressure
Red Air Line – MPG
leak signal