Resin transfer method

[chil wilson]

We have a fiberglass manufacturing facility that used open molding for large parts. We are trying RTM to build some smaller items and it is our first attempt. My background is mechanical. I am trying to figure out the true pressure inside the space that is 30" OD and has a cavity 1.5" deep packed with Matt fiberglass as well as mat/cor-rove/mat stitched, 18 layer thick. we are using unsaturated 32% syyrine Arapol resin at 80 DEG F with a centipoise of 480. The pump is a 7:1 ratio putting out .08 gallons per stroke at 126 PSIG. Wouldn't it make sense that as the thick resin is injected the mold pressure would rise above 126 PSIG to penetrate all the layers. If so does anyone know how to calculate that? I can use my pressure vessel calculations for the top head but is seems we are getting flexion and loosing vacuum so the pressure must be higher than we think in the chamber.

Chil Wilson V.P.

 

[Compositepro]

Are you using an air driven pump, and your air pressure is 126 psi? Then your resin pressure will be seven times you air pressure or 882 psi. On a 30" diameter cavity you would have over 600,000 pound of force trying to open your mold. Air driven pumps should have a air pressure regulator on the air supply. This is used to control the maximum resin pressure (seven times the air pressure).

 

[chil wilson]

We are using 18 PSI on the 7:1 air powered pump with a regulator. It pumps .08 gpm per stroke both up and down. So it should be 126 psi at the inlet. The inlet is in the edge of the mold and vacuum in the center

Chil Wilson V.P.

 

[Compositepro]

I give up for now. I'm not going to play 20 questions with you to help you solve your problem. What do you think the problem is? You mold seal is not working. Why?.

 

[chil wilson]

What ever you haven said anything I don’t know anyway

Chil Wilson V.P.