Magnum Venus Plastech Hypaject MK III - Manual (Page 13)

Hypaject MK III Instructions Issue 07: April 2001-04-23 13
9. Inject as per section 4.3
10. When the injection is complete, do not close the inject valve until the vacuum on the tool
has been switched off and allowed to decay. It is very important to finish the injection
with a slight positive pressure on the cavity.
11. Turn off pressure to the Dynamic Seal.
Note : When operating at temperatures above 100°C it may be necessary to remove the
pressure from the inner seal at the end of the injection. Tests have shown that at higher
temperatures, it is possible for small air bubbles to leak through the seal and create voids in
the laminate edge.
Never turn this seal off during the injection stage. When using standard
thermosetting resins at lower temperatures the inner seal should be left inflated
throughout the cycle.
12. Allow the part to cure according to the resin manufacturers recommendations.
13. It is very important that the mould temperature is constant and that it does not drop
throughout the injection and curing periods.
14. NOTE: Use of Pre-Heating Plate. When using injection resin that requires pre-heating
to a specific activation temperature (such as 3M- PR500) the back plate assembly can
be used. The back plate is located onto the back of the mould surface using the 6 X
M10 bolts provided with the Autosprue position at the opposite end to the injection point
into the mould. The Autosprue is clamped into position using the same clamping
mechanism. In this configuration the resin is forced through the pre-heat channel prior to
entry into the fibre pack, thus bringing it up to the same temperature as the mould
surface. The surfaces of the back plate and the back surface of the mould must be
maintained with the same release agent as the rest of the mould (see Mould Release
Agent Specification Sheet)