Magnum Venus Plastech DP-1000 (EPO3) - Manual (Page 25)

CHAPTER 7
RESIN INJECTION
Requirements
The RTM (Resin Transfer Molding) is identical to the spraying process with the exception of the lower
operating pressures. It may be possible to operate MAIN PRESSURE at the same pressure as recirculation
pressure, eliminating some procedures necessary for balancing startup pressures.
Resin injection also requires the use of a static-mixing tube attached to the standard gun-head to achieve
proper blending of tube components. Static mixing tubes are available in ¼”, 3/8”, ½” and ¾” sizes depending
upon flow rate requirements.
Caution: Mixing tubes are precision instruments and must be handled with extreme care.
Testing RTM Mix
To check proper mix for RTM, use the following procedure:

Lay a narrow strip of material across a piece of paper and check for pump pulsations during pouring
process.

Inspect material for full Barcol hardness or use other industry standard method to test for proper
hardness.

Any uncured area in this test strip indicates one or more of the following problems:

Accumulators are charged with either too little or too much pressure.

Accumulator volume is not properly matched to the pumping ratio or material viscosity.

Pump cavitation is occurring due to improper feeding of pump inlet or improper action of inlet ball.

Fluid restriction or blockage is occurring.

Pump pressures are fluctuating excessively during the switch from recirculation to the main operating
pressure.

Loose fittings on the inlet hoses (pump diving).
Caution: Flush the gun between resin injection operations to avoid ruining the static-mixing tubes.